extent_io.c 141.1 KB
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#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/bio.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/page-flags.h>
#include <linux/spinlock.h>
#include <linux/blkdev.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/pagevec.h>
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#include <linux/prefetch.h>
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#include <linux/cleancache.h>
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#include "extent_io.h"
#include "extent_map.h"
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#include "ctree.h"
#include "btrfs_inode.h"
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#include "volumes.h"
19
#include "check-integrity.h"
20
#include "locking.h"
21
#include "rcu-string.h"
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#include "backref.h"
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static struct kmem_cache *extent_state_cache;
static struct kmem_cache *extent_buffer_cache;
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static struct bio_set *btrfs_bioset;
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static inline bool extent_state_in_tree(const struct extent_state *state)
{
	return !RB_EMPTY_NODE(&state->rb_node);
}

33
#ifdef CONFIG_BTRFS_DEBUG
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static LIST_HEAD(buffers);
static LIST_HEAD(states);
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static DEFINE_SPINLOCK(leak_lock);
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static inline
void btrfs_leak_debug_add(struct list_head *new, struct list_head *head)
{
	unsigned long flags;

	spin_lock_irqsave(&leak_lock, flags);
	list_add(new, head);
	spin_unlock_irqrestore(&leak_lock, flags);
}

static inline
void btrfs_leak_debug_del(struct list_head *entry)
{
	unsigned long flags;

	spin_lock_irqsave(&leak_lock, flags);
	list_del(entry);
	spin_unlock_irqrestore(&leak_lock, flags);
}

static inline
void btrfs_leak_debug_check(void)
{
	struct extent_state *state;
	struct extent_buffer *eb;

	while (!list_empty(&states)) {
		state = list_entry(states.next, struct extent_state, leak_list);
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		pr_err("BTRFS: state leak: start %llu end %llu state %u in tree %d refs %d\n",
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		       state->start, state->end, state->state,
		       extent_state_in_tree(state),
70
		       atomic_read(&state->refs));
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		list_del(&state->leak_list);
		kmem_cache_free(extent_state_cache, state);
	}

	while (!list_empty(&buffers)) {
		eb = list_entry(buffers.next, struct extent_buffer, leak_list);
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		printk(KERN_ERR "BTRFS: buffer leak start %llu len %lu "
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		       "refs %d\n",
		       eb->start, eb->len, atomic_read(&eb->refs));
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		list_del(&eb->leak_list);
		kmem_cache_free(extent_buffer_cache, eb);
	}
}
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#define btrfs_debug_check_extent_io_range(tree, start, end)		\
	__btrfs_debug_check_extent_io_range(__func__, (tree), (start), (end))
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static inline void __btrfs_debug_check_extent_io_range(const char *caller,
88
		struct extent_io_tree *tree, u64 start, u64 end)
89
{
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	struct inode *inode;
	u64 isize;
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93 94
	if (!tree->mapping)
		return;
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	inode = tree->mapping->host;
	isize = i_size_read(inode);
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	if (end >= PAGE_SIZE && (end % 2) == 0 && end != isize - 1) {
		printk_ratelimited(KERN_DEBUG
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		    "BTRFS: %s: ino %llu isize %llu odd range [%llu,%llu]\n",
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				caller, btrfs_ino(inode), isize, start, end);
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	}
}
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#else
#define btrfs_leak_debug_add(new, head)	do {} while (0)
#define btrfs_leak_debug_del(entry)	do {} while (0)
#define btrfs_leak_debug_check()	do {} while (0)
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#define btrfs_debug_check_extent_io_range(c, s, e)	do {} while (0)
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#endif
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#define BUFFER_LRU_MAX 64

struct tree_entry {
	u64 start;
	u64 end;
	struct rb_node rb_node;
};

struct extent_page_data {
	struct bio *bio;
	struct extent_io_tree *tree;
	get_extent_t *get_extent;
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	unsigned long bio_flags;
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	/* tells writepage not to lock the state bits for this range
	 * it still does the unlocking
	 */
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	unsigned int extent_locked:1;

	/* tells the submit_bio code to use a WRITE_SYNC */
	unsigned int sync_io:1;
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};

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static noinline void flush_write_bio(void *data);
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static inline struct btrfs_fs_info *
tree_fs_info(struct extent_io_tree *tree)
{
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	if (!tree->mapping)
		return NULL;
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	return btrfs_sb(tree->mapping->host->i_sb);
}
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int __init extent_io_init(void)
{
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	extent_state_cache = kmem_cache_create("btrfs_extent_state",
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			sizeof(struct extent_state), 0,
			SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
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	if (!extent_state_cache)
		return -ENOMEM;

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	extent_buffer_cache = kmem_cache_create("btrfs_extent_buffer",
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			sizeof(struct extent_buffer), 0,
			SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
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	if (!extent_buffer_cache)
		goto free_state_cache;
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	btrfs_bioset = bioset_create(BIO_POOL_SIZE,
				     offsetof(struct btrfs_io_bio, bio));
	if (!btrfs_bioset)
		goto free_buffer_cache;
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	if (bioset_integrity_create(btrfs_bioset, BIO_POOL_SIZE))
		goto free_bioset;

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	return 0;

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free_bioset:
	bioset_free(btrfs_bioset);
	btrfs_bioset = NULL;

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free_buffer_cache:
	kmem_cache_destroy(extent_buffer_cache);
	extent_buffer_cache = NULL;

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free_state_cache:
	kmem_cache_destroy(extent_state_cache);
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	extent_state_cache = NULL;
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	return -ENOMEM;
}

void extent_io_exit(void)
{
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	btrfs_leak_debug_check();
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	/*
	 * Make sure all delayed rcu free are flushed before we
	 * destroy caches.
	 */
	rcu_barrier();
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	if (extent_state_cache)
		kmem_cache_destroy(extent_state_cache);
	if (extent_buffer_cache)
		kmem_cache_destroy(extent_buffer_cache);
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	if (btrfs_bioset)
		bioset_free(btrfs_bioset);
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}

void extent_io_tree_init(struct extent_io_tree *tree,
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			 struct address_space *mapping)
200
{
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	tree->state = RB_ROOT;
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	tree->ops = NULL;
	tree->dirty_bytes = 0;
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	spin_lock_init(&tree->lock);
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	tree->mapping = mapping;
}

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static struct extent_state *alloc_extent_state(gfp_t mask)
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{
	struct extent_state *state;

	state = kmem_cache_alloc(extent_state_cache, mask);
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	if (!state)
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		return state;
	state->state = 0;
	state->private = 0;
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	RB_CLEAR_NODE(&state->rb_node);
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	btrfs_leak_debug_add(&state->leak_list, &states);
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	atomic_set(&state->refs, 1);
	init_waitqueue_head(&state->wq);
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	trace_alloc_extent_state(state, mask, _RET_IP_);
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	return state;
}

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void free_extent_state(struct extent_state *state)
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{
	if (!state)
		return;
	if (atomic_dec_and_test(&state->refs)) {
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		WARN_ON(extent_state_in_tree(state));
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		btrfs_leak_debug_del(&state->leak_list);
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		trace_free_extent_state(state, _RET_IP_);
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		kmem_cache_free(extent_state_cache, state);
	}
}

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static struct rb_node *tree_insert(struct rb_root *root,
				   struct rb_node *search_start,
				   u64 offset,
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				   struct rb_node *node,
				   struct rb_node ***p_in,
				   struct rb_node **parent_in)
243
{
244
	struct rb_node **p;
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	struct rb_node *parent = NULL;
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	struct tree_entry *entry;

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	if (p_in && parent_in) {
		p = *p_in;
		parent = *parent_in;
		goto do_insert;
	}

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	p = search_start ? &search_start : &root->rb_node;
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	while (*p) {
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		parent = *p;
		entry = rb_entry(parent, struct tree_entry, rb_node);

		if (offset < entry->start)
			p = &(*p)->rb_left;
		else if (offset > entry->end)
			p = &(*p)->rb_right;
		else
			return parent;
	}

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do_insert:
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	rb_link_node(node, parent, p);
	rb_insert_color(node, root);
	return NULL;
}

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static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
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				      struct rb_node **prev_ret,
				      struct rb_node **next_ret,
				      struct rb_node ***p_ret,
				      struct rb_node **parent_ret)
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{
279
	struct rb_root *root = &tree->state;
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	struct rb_node **n = &root->rb_node;
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	struct rb_node *prev = NULL;
	struct rb_node *orig_prev = NULL;
	struct tree_entry *entry;
	struct tree_entry *prev_entry = NULL;

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	while (*n) {
		prev = *n;
		entry = rb_entry(prev, struct tree_entry, rb_node);
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		prev_entry = entry;

		if (offset < entry->start)
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			n = &(*n)->rb_left;
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		else if (offset > entry->end)
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			n = &(*n)->rb_right;
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		else
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			return *n;
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	}

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	if (p_ret)
		*p_ret = n;
	if (parent_ret)
		*parent_ret = prev;

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	if (prev_ret) {
		orig_prev = prev;
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		while (prev && offset > prev_entry->end) {
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			prev = rb_next(prev);
			prev_entry = rb_entry(prev, struct tree_entry, rb_node);
		}
		*prev_ret = prev;
		prev = orig_prev;
	}

	if (next_ret) {
		prev_entry = rb_entry(prev, struct tree_entry, rb_node);
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		while (prev && offset < prev_entry->start) {
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			prev = rb_prev(prev);
			prev_entry = rb_entry(prev, struct tree_entry, rb_node);
		}
		*next_ret = prev;
	}
	return NULL;
}

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static inline struct rb_node *
tree_search_for_insert(struct extent_io_tree *tree,
		       u64 offset,
		       struct rb_node ***p_ret,
		       struct rb_node **parent_ret)
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{
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	struct rb_node *prev = NULL;
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	struct rb_node *ret;
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334
	ret = __etree_search(tree, offset, &prev, NULL, p_ret, parent_ret);
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	if (!ret)
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		return prev;
	return ret;
}

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static inline struct rb_node *tree_search(struct extent_io_tree *tree,
					  u64 offset)
{
	return tree_search_for_insert(tree, offset, NULL, NULL);
}

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static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
		     struct extent_state *other)
{
	if (tree->ops && tree->ops->merge_extent_hook)
		tree->ops->merge_extent_hook(tree->mapping->host, new,
					     other);
}

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/*
 * utility function to look for merge candidates inside a given range.
 * Any extents with matching state are merged together into a single
 * extent in the tree.  Extents with EXTENT_IO in their state field
 * are not merged because the end_io handlers need to be able to do
 * operations on them without sleeping (or doing allocations/splits).
 *
 * This should be called with the tree lock held.
 */
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static void merge_state(struct extent_io_tree *tree,
		        struct extent_state *state)
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{
	struct extent_state *other;
	struct rb_node *other_node;

369
	if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
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		return;
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	other_node = rb_prev(&state->rb_node);
	if (other_node) {
		other = rb_entry(other_node, struct extent_state, rb_node);
		if (other->end == state->start - 1 &&
		    other->state == state->state) {
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			merge_cb(tree, state, other);
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			state->start = other->start;
			rb_erase(&other->rb_node, &tree->state);
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			RB_CLEAR_NODE(&other->rb_node);
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			free_extent_state(other);
		}
	}
	other_node = rb_next(&state->rb_node);
	if (other_node) {
		other = rb_entry(other_node, struct extent_state, rb_node);
		if (other->start == state->end + 1 &&
		    other->state == state->state) {
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			merge_cb(tree, state, other);
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			state->end = other->end;
			rb_erase(&other->rb_node, &tree->state);
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			RB_CLEAR_NODE(&other->rb_node);
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			free_extent_state(other);
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		}
	}
}

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static void set_state_cb(struct extent_io_tree *tree,
399
			 struct extent_state *state, unsigned *bits)
400
{
401 402
	if (tree->ops && tree->ops->set_bit_hook)
		tree->ops->set_bit_hook(tree->mapping->host, state, bits);
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}

static void clear_state_cb(struct extent_io_tree *tree,
406
			   struct extent_state *state, unsigned *bits)
407
{
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	if (tree->ops && tree->ops->clear_bit_hook)
		tree->ops->clear_bit_hook(tree->mapping->host, state, bits);
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}

412
static void set_state_bits(struct extent_io_tree *tree,
413
			   struct extent_state *state, unsigned *bits);
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/*
 * insert an extent_state struct into the tree.  'bits' are set on the
 * struct before it is inserted.
 *
 * This may return -EEXIST if the extent is already there, in which case the
 * state struct is freed.
 *
 * The tree lock is not taken internally.  This is a utility function and
 * probably isn't what you want to call (see set/clear_extent_bit).
 */
static int insert_state(struct extent_io_tree *tree,
			struct extent_state *state, u64 start, u64 end,
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			struct rb_node ***p,
			struct rb_node **parent,
429
			unsigned *bits)
430 431 432
{
	struct rb_node *node;

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	if (end < start)
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		WARN(1, KERN_ERR "BTRFS: end < start %llu %llu\n",
435
		       end, start);
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	state->start = start;
	state->end = end;
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439 440
	set_state_bits(tree, state, bits);

441
	node = tree_insert(&tree->state, NULL, end, &state->rb_node, p, parent);
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	if (node) {
		struct extent_state *found;
		found = rb_entry(node, struct extent_state, rb_node);
445
		printk(KERN_ERR "BTRFS: found node %llu %llu on insert of "
446 447
		       "%llu %llu\n",
		       found->start, found->end, start, end);
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		return -EEXIST;
	}
	merge_state(tree, state);
	return 0;
}

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static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
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		     u64 split)
{
	if (tree->ops && tree->ops->split_extent_hook)
458
		tree->ops->split_extent_hook(tree->mapping->host, orig, split);
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}

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/*
 * split a given extent state struct in two, inserting the preallocated
 * struct 'prealloc' as the newly created second half.  'split' indicates an
 * offset inside 'orig' where it should be split.
 *
 * Before calling,
 * the tree has 'orig' at [orig->start, orig->end].  After calling, there
 * are two extent state structs in the tree:
 * prealloc: [orig->start, split - 1]
 * orig: [ split, orig->end ]
 *
 * The tree locks are not taken by this function. They need to be held
 * by the caller.
 */
static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
		       struct extent_state *prealloc, u64 split)
{
	struct rb_node *node;
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	split_cb(tree, orig, split);

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	prealloc->start = orig->start;
	prealloc->end = split - 1;
	prealloc->state = orig->state;
	orig->start = split;

487 488
	node = tree_insert(&tree->state, &orig->rb_node, prealloc->end,
			   &prealloc->rb_node, NULL, NULL);
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	if (node) {
		free_extent_state(prealloc);
		return -EEXIST;
	}
	return 0;
}

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static struct extent_state *next_state(struct extent_state *state)
{
	struct rb_node *next = rb_next(&state->rb_node);
	if (next)
		return rb_entry(next, struct extent_state, rb_node);
	else
		return NULL;
}

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/*
 * utility function to clear some bits in an extent state struct.
507
 * it will optionally wake up any one waiting on this state (wake == 1).
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 *
 * If no bits are set on the state struct after clearing things, the
 * struct is freed and removed from the tree
 */
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static struct extent_state *clear_state_bit(struct extent_io_tree *tree,
					    struct extent_state *state,
514
					    unsigned *bits, int wake)
515
{
516
	struct extent_state *next;
517
	unsigned bits_to_clear = *bits & ~EXTENT_CTLBITS;
518

519
	if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
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		u64 range = state->end - state->start + 1;
		WARN_ON(range > tree->dirty_bytes);
		tree->dirty_bytes -= range;
	}
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	clear_state_cb(tree, state, bits);
525
	state->state &= ~bits_to_clear;
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	if (wake)
		wake_up(&state->wq);
528
	if (state->state == 0) {
529
		next = next_state(state);
530
		if (extent_state_in_tree(state)) {
531
			rb_erase(&state->rb_node, &tree->state);
532
			RB_CLEAR_NODE(&state->rb_node);
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			free_extent_state(state);
		} else {
			WARN_ON(1);
		}
	} else {
		merge_state(tree, state);
539
		next = next_state(state);
540
	}
541
	return next;
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}

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static struct extent_state *
alloc_extent_state_atomic(struct extent_state *prealloc)
{
	if (!prealloc)
		prealloc = alloc_extent_state(GFP_ATOMIC);

	return prealloc;
}

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static void extent_io_tree_panic(struct extent_io_tree *tree, int err)
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{
	btrfs_panic(tree_fs_info(tree), err, "Locking error: "
		    "Extent tree was modified by another "
		    "thread while locked.");
}

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/*
 * clear some bits on a range in the tree.  This may require splitting
 * or inserting elements in the tree, so the gfp mask is used to
 * indicate which allocations or sleeping are allowed.
 *
 * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
 * the given range from the tree regardless of state (ie for truncate).
 *
 * the range [start, end] is inclusive.
 *
570
 * This takes the tree lock, and returns 0 on success and < 0 on error.
571 572
 */
int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
573
		     unsigned bits, int wake, int delete,
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		     struct extent_state **cached_state,
		     gfp_t mask)
576 577
{
	struct extent_state *state;
578
	struct extent_state *cached;
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	struct extent_state *prealloc = NULL;
	struct rb_node *node;
581
	u64 last_end;
582
	int err;
583
	int clear = 0;
584

585
	btrfs_debug_check_extent_io_range(tree, start, end);
586

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	if (bits & EXTENT_DELALLOC)
		bits |= EXTENT_NORESERVE;

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	if (delete)
		bits |= ~EXTENT_CTLBITS;
	bits |= EXTENT_FIRST_DELALLOC;

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	if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
		clear = 1;
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again:
	if (!prealloc && (mask & __GFP_WAIT)) {
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		/*
		 * Don't care for allocation failure here because we might end
		 * up not needing the pre-allocated extent state at all, which
		 * is the case if we only have in the tree extent states that
		 * cover our input range and don't cover too any other range.
		 * If we end up needing a new extent state we allocate it later.
		 */
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		prealloc = alloc_extent_state(mask);
	}

608
	spin_lock(&tree->lock);
609 610
	if (cached_state) {
		cached = *cached_state;
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		if (clear) {
			*cached_state = NULL;
			cached_state = NULL;
		}

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		if (cached && extent_state_in_tree(cached) &&
		    cached->start <= start && cached->end > start) {
619 620
			if (clear)
				atomic_dec(&cached->refs);
621
			state = cached;
622
			goto hit_next;
623
		}
624 625
		if (clear)
			free_extent_state(cached);
626
	}
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	/*
	 * this search will find the extents that end after
	 * our range starts
	 */
631
	node = tree_search(tree, start);
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	if (!node)
		goto out;
	state = rb_entry(node, struct extent_state, rb_node);
635
hit_next:
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	if (state->start > end)
		goto out;
	WARN_ON(state->end < start);
639
	last_end = state->end;
640

641
	/* the state doesn't have the wanted bits, go ahead */
642 643
	if (!(state->state & bits)) {
		state = next_state(state);
644
		goto next;
645
	}
646

647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663
	/*
	 *     | ---- desired range ---- |
	 *  | state | or
	 *  | ------------- state -------------- |
	 *
	 * We need to split the extent we found, and may flip
	 * bits on second half.
	 *
	 * If the extent we found extends past our range, we
	 * just split and search again.  It'll get split again
	 * the next time though.
	 *
	 * If the extent we found is inside our range, we clear
	 * the desired bit on it.
	 */

	if (state->start < start) {
664 665
		prealloc = alloc_extent_state_atomic(prealloc);
		BUG_ON(!prealloc);
666
		err = split_state(tree, state, prealloc, start);
667 668 669
		if (err)
			extent_io_tree_panic(tree, err);

670 671 672 673
		prealloc = NULL;
		if (err)
			goto out;
		if (state->end <= end) {
674 675
			state = clear_state_bit(tree, state, &bits, wake);
			goto next;
676 677 678 679 680 681 682 683 684 685
		}
		goto search_again;
	}
	/*
	 * | ---- desired range ---- |
	 *                        | state |
	 * We need to split the extent, and clear the bit
	 * on the first half
	 */
	if (state->start <= end && state->end > end) {
686 687
		prealloc = alloc_extent_state_atomic(prealloc);
		BUG_ON(!prealloc);
688
		err = split_state(tree, state, prealloc, end + 1);
689 690 691
		if (err)
			extent_io_tree_panic(tree, err);

692 693
		if (wake)
			wake_up(&state->wq);
694

695
		clear_state_bit(tree, prealloc, &bits, wake);
J
Josef Bacik 已提交
696

697 698 699
		prealloc = NULL;
		goto out;
	}
700

701
	state = clear_state_bit(tree, state, &bits, wake);
702
next:
703 704 705
	if (last_end == (u64)-1)
		goto out;
	start = last_end + 1;
706
	if (start <= end && state && !need_resched())
707
		goto hit_next;
708 709 710
	goto search_again;

out:
711
	spin_unlock(&tree->lock);
712 713 714
	if (prealloc)
		free_extent_state(prealloc);

715
	return 0;
716 717 718 719

search_again:
	if (start > end)
		goto out;
720
	spin_unlock(&tree->lock);
721 722 723 724 725
	if (mask & __GFP_WAIT)
		cond_resched();
	goto again;
}

726 727
static void wait_on_state(struct extent_io_tree *tree,
			  struct extent_state *state)
728 729
		__releases(tree->lock)
		__acquires(tree->lock)
730 731 732
{
	DEFINE_WAIT(wait);
	prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
733
	spin_unlock(&tree->lock);
734
	schedule();
735
	spin_lock(&tree->lock);
736 737 738 739 740 741 742 743
	finish_wait(&state->wq, &wait);
}

/*
 * waits for one or more bits to clear on a range in the state tree.
 * The range [start, end] is inclusive.
 * The tree lock is taken by this function
 */
744 745
static void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
			    unsigned long bits)
746 747 748 749
{
	struct extent_state *state;
	struct rb_node *node;

750
	btrfs_debug_check_extent_io_range(tree, start, end);
751

752
	spin_lock(&tree->lock);
753 754 755 756 757 758
again:
	while (1) {
		/*
		 * this search will find all the extents that end after
		 * our range starts
		 */
759
		node = tree_search(tree, start);
760
process_node:
761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780
		if (!node)
			break;

		state = rb_entry(node, struct extent_state, rb_node);

		if (state->start > end)
			goto out;

		if (state->state & bits) {
			start = state->start;
			atomic_inc(&state->refs);
			wait_on_state(tree, state);
			free_extent_state(state);
			goto again;
		}
		start = state->end + 1;

		if (start > end)
			break;

781 782 783 784
		if (!cond_resched_lock(&tree->lock)) {
			node = rb_next(node);
			goto process_node;
		}
785 786
	}
out:
787
	spin_unlock(&tree->lock);
788 789
}

790
static void set_state_bits(struct extent_io_tree *tree,
791
			   struct extent_state *state,
792
			   unsigned *bits)
793
{
794
	unsigned bits_to_set = *bits & ~EXTENT_CTLBITS;
J
Josef Bacik 已提交
795

796
	set_state_cb(tree, state, bits);
797
	if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
798 799 800
		u64 range = state->end - state->start + 1;
		tree->dirty_bytes += range;
	}
801
	state->state |= bits_to_set;
802 803
}

804 805
static void cache_state_if_flags(struct extent_state *state,
				 struct extent_state **cached_ptr,
806
				 unsigned flags)
807 808
{
	if (cached_ptr && !(*cached_ptr)) {
809
		if (!flags || (state->state & flags)) {
810 811 812 813 814 815
			*cached_ptr = state;
			atomic_inc(&state->refs);
		}
	}
}

816 817 818 819 820 821 822
static void cache_state(struct extent_state *state,
			struct extent_state **cached_ptr)
{
	return cache_state_if_flags(state, cached_ptr,
				    EXTENT_IOBITS | EXTENT_BOUNDARY);
}

823
/*
824 825
 * set some bits on a range in the tree.  This may require allocations or
 * sleeping, so the gfp mask is used to indicate what is allowed.
826
 *
827 828 829
 * If any of the exclusive bits are set, this will fail with -EEXIST if some
 * part of the range already has the desired bits set.  The start of the
 * existing range is returned in failed_start in this case.
830
 *
831
 * [start, end] is inclusive This takes the tree lock.
832
 */
833

J
Jeff Mahoney 已提交
834 835
static int __must_check
__set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
836
		 unsigned bits, unsigned exclusive_bits,
837 838
		 u64 *failed_start, struct extent_state **cached_state,
		 gfp_t mask)
839 840 841 842
{
	struct extent_state *state;
	struct extent_state *prealloc = NULL;
	struct rb_node *node;
843 844
	struct rb_node **p;
	struct rb_node *parent;
845 846 847
	int err = 0;
	u64 last_start;
	u64 last_end;
848

849
	btrfs_debug_check_extent_io_range(tree, start, end);
850

851
	bits |= EXTENT_FIRST_DELALLOC;
852 853 854
again:
	if (!prealloc && (mask & __GFP_WAIT)) {
		prealloc = alloc_extent_state(mask);
855
		BUG_ON(!prealloc);
856 857
	}

858
	spin_lock(&tree->lock);
859 860
	if (cached_state && *cached_state) {
		state = *cached_state;
861
		if (state->start <= start && state->end > start &&
862
		    extent_state_in_tree(state)) {
863 864 865 866
			node = &state->rb_node;
			goto hit_next;
		}
	}
867 868 869 870
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
871
	node = tree_search_for_insert(tree, start, &p, &parent);
872
	if (!node) {
873 874
		prealloc = alloc_extent_state_atomic(prealloc);
		BUG_ON(!prealloc);
875 876
		err = insert_state(tree, prealloc, start, end,
				   &p, &parent, &bits);
877 878 879
		if (err)
			extent_io_tree_panic(tree, err);

880
		cache_state(prealloc, cached_state);
881 882 883 884
		prealloc = NULL;
		goto out;
	}
	state = rb_entry(node, struct extent_state, rb_node);
C
Chris Mason 已提交
885
hit_next:
886 887 888 889 890 891 892 893 894 895
	last_start = state->start;
	last_end = state->end;

	/*
	 * | ---- desired range ---- |
	 * | state |
	 *
	 * Just lock what we found and keep going
	 */
	if (state->start == start && state->end <= end) {
896
		if (state->state & exclusive_bits) {
897 898 899 900
			*failed_start = state->start;
			err = -EEXIST;
			goto out;
		}
901

902
		set_state_bits(tree, state, &bits);
903
		cache_state(state, cached_state);
904
		merge_state(tree, state);
905 906 907
		if (last_end == (u64)-1)
			goto out;
		start = last_end + 1;
908 909 910 911
		state = next_state(state);
		if (start < end && state && state->start == start &&
		    !need_resched())
			goto hit_next;
912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931
		goto search_again;
	}

	/*
	 *     | ---- desired range ---- |
	 * | state |
	 *   or
	 * | ------------- state -------------- |
	 *
	 * We need to split the extent we found, and may flip bits on
	 * second half.
	 *
	 * If the extent we found extends past our
	 * range, we just split and search again.  It'll get split
	 * again the next time though.
	 *
	 * If the extent we found is inside our range, we set the
	 * desired bit on it.
	 */
	if (state->start < start) {
932
		if (state->state & exclusive_bits) {
933 934 935 936
			*failed_start = start;
			err = -EEXIST;
			goto out;
		}
937 938 939

		prealloc = alloc_extent_state_atomic(prealloc);
		BUG_ON(!prealloc);
940
		err = split_state(tree, state, prealloc, start);
941 942 943
		if (err)
			extent_io_tree_panic(tree, err);

944 945 946 947
		prealloc = NULL;
		if (err)
			goto out;
		if (state->end <= end) {
948
			set_state_bits(tree, state, &bits);
949
			cache_state(state, cached_state);
950
			merge_state(tree, state);
951 952 953
			if (last_end == (u64)-1)
				goto out;
			start = last_end + 1;
954 955 956 957
			state = next_state(state);
			if (start < end && state && state->start == start &&
			    !need_resched())
				goto hit_next;
958 959 960 961 962 963 964 965 966 967 968 969 970 971 972
		}
		goto search_again;
	}
	/*
	 * | ---- desired range ---- |
	 *     | state | or               | state |
	 *
	 * There's a hole, we need to insert something in it and
	 * ignore the extent we found.
	 */
	if (state->start > start) {
		u64 this_end;
		if (end < last_start)
			this_end = end;
		else
C
Chris Mason 已提交
973
			this_end = last_start - 1;
974 975 976

		prealloc = alloc_extent_state_atomic(prealloc);
		BUG_ON(!prealloc);
977 978 979 980 981

		/*
		 * Avoid to free 'prealloc' if it can be merged with
		 * the later extent.
		 */
982
		err = insert_state(tree, prealloc, start, this_end,
983
				   NULL, NULL, &bits);
984 985 986
		if (err)
			extent_io_tree_panic(tree, err);

J
Josef Bacik 已提交
987 988
		cache_state(prealloc, cached_state);
		prealloc = NULL;
989 990 991 992 993 994 995 996 997 998
		start = this_end + 1;
		goto search_again;
	}
	/*
	 * | ---- desired range ---- |
	 *                        | state |
	 * We need to split the extent, and set the bit
	 * on the first half
	 */
	if (state->start <= end && state->end > end) {
999
		if (state->state & exclusive_bits) {
1000 1001 1002 1003
			*failed_start = start;
			err = -EEXIST;
			goto out;
		}
1004 1005 1006

		prealloc = alloc_extent_state_atomic(prealloc);
		BUG_ON(!prealloc);
1007
		err = split_state(tree, state, prealloc, end + 1);
1008 1009
		if (err)
			extent_io_tree_panic(tree, err);
1010

1011
		set_state_bits(tree, prealloc, &bits);
1012
		cache_state(prealloc, cached_state);
1013 1014 1015 1016 1017 1018 1019 1020
		merge_state(tree, prealloc);
		prealloc = NULL;
		goto out;
	}

	goto search_again;

out:
1021
	spin_unlock(&tree->lock);
1022 1023 1024 1025 1026 1027 1028 1029
	if (prealloc)
		free_extent_state(prealloc);

	return err;

search_again:
	if (start > end)
		goto out;
1030
	spin_unlock(&tree->lock);
1031 1032 1033 1034 1035
	if (mask & __GFP_WAIT)
		cond_resched();
	goto again;
}

1036
int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1037
		   unsigned bits, u64 * failed_start,
1038
		   struct extent_state **cached_state, gfp_t mask)
J
Jeff Mahoney 已提交
1039 1040 1041 1042 1043 1044
{
	return __set_extent_bit(tree, start, end, bits, 0, failed_start,
				cached_state, mask);
}


J
Josef Bacik 已提交
1045
/**
L
Liu Bo 已提交
1046 1047
 * convert_extent_bit - convert all bits in a given range from one bit to
 * 			another
J
Josef Bacik 已提交
1048 1049 1050 1051 1052
 * @tree:	the io tree to search
 * @start:	the start offset in bytes
 * @end:	the end offset in bytes (inclusive)
 * @bits:	the bits to set in this range
 * @clear_bits:	the bits to clear in this range
1053
 * @cached_state:	state that we're going to cache
J
Josef Bacik 已提交
1054 1055 1056 1057 1058 1059 1060 1061 1062
 * @mask:	the allocation mask
 *
 * This will go through and set bits for the given range.  If any states exist
 * already in this range they are set with the given bit and cleared of the
 * clear_bits.  This is only meant to be used by things that are mergeable, ie
 * converting from say DELALLOC to DIRTY.  This is not meant to be used with
 * boundary bits like LOCK.
 */
int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
1063
		       unsigned bits, unsigned clear_bits,
1064
		       struct extent_state **cached_state, gfp_t mask)
J
Josef Bacik 已提交
1065 1066 1067 1068
{
	struct extent_state *state;
	struct extent_state *prealloc = NULL;
	struct rb_node *node;
1069 1070
	struct rb_node **p;
	struct rb_node *parent;
J
Josef Bacik 已提交
1071 1072 1073
	int err = 0;
	u64 last_start;
	u64 last_end;
1074
	bool first_iteration = true;
J
Josef Bacik 已提交
1075

1076
	btrfs_debug_check_extent_io_range(tree, start, end);
1077

J
Josef Bacik 已提交
1078 1079
again:
	if (!prealloc && (mask & __GFP_WAIT)) {
1080 1081 1082 1083 1084 1085 1086
		/*
		 * Best effort, don't worry if extent state allocation fails
		 * here for the first iteration. We might have a cached state
		 * that matches exactly the target range, in which case no
		 * extent state allocations are needed. We'll only know this
		 * after locking the tree.
		 */
J
Josef Bacik 已提交
1087
		prealloc = alloc_extent_state(mask);
1088
		if (!prealloc && !first_iteration)
J
Josef Bacik 已提交
1089 1090 1091 1092
			return -ENOMEM;
	}

	spin_lock(&tree->lock);
1093 1094 1095
	if (cached_state && *cached_state) {
		state = *cached_state;
		if (state->start <= start && state->end > start &&
1096
		    extent_state_in_tree(state)) {
1097 1098 1099 1100 1101
			node = &state->rb_node;
			goto hit_next;
		}
	}

J
Josef Bacik 已提交
1102 1103 1104 1105
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1106
	node = tree_search_for_insert(tree, start, &p, &parent);
J
Josef Bacik 已提交
1107 1108
	if (!node) {
		prealloc = alloc_extent_state_atomic(prealloc);
1109 1110 1111 1112
		if (!prealloc) {
			err = -ENOMEM;
			goto out;
		}
1113 1114
		err = insert_state(tree, prealloc, start, end,
				   &p, &parent, &bits);
1115 1116
		if (err)
			extent_io_tree_panic(tree, err);
1117 1118
		cache_state(prealloc, cached_state);
		prealloc = NULL;
J
Josef Bacik 已提交
1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133
		goto out;
	}
	state = rb_entry(node, struct extent_state, rb_node);
hit_next:
	last_start = state->start;
	last_end = state->end;

	/*
	 * | ---- desired range ---- |
	 * | state |
	 *
	 * Just lock what we found and keep going
	 */
	if (state->start == start && state->end <= end) {
		set_state_bits(tree, state, &bits);
1134
		cache_state(state, cached_state);
1135
		state = clear_state_bit(tree, state, &clear_bits, 0);
J
Josef Bacik 已提交
1136 1137 1138
		if (last_end == (u64)-1)
			goto out;
		start = last_end + 1;
1139 1140 1141
		if (start < end && state && state->start == start &&
		    !need_resched())
			goto hit_next;
J
Josef Bacik 已提交
1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162
		goto search_again;
	}

	/*
	 *     | ---- desired range ---- |
	 * | state |
	 *   or
	 * | ------------- state -------------- |
	 *
	 * We need to split the extent we found, and may flip bits on
	 * second half.
	 *
	 * If the extent we found extends past our
	 * range, we just split and search again.  It'll get split
	 * again the next time though.
	 *
	 * If the extent we found is inside our range, we set the
	 * desired bit on it.
	 */
	if (state->start < start) {
		prealloc = alloc_extent_state_atomic(prealloc);
1163 1164 1165 1166
		if (!prealloc) {
			err = -ENOMEM;
			goto out;
		}
J
Josef Bacik 已提交
1167
		err = split_state(tree, state, prealloc, start);
1168 1169
		if (err)
			extent_io_tree_panic(tree, err);
J
Josef Bacik 已提交
1170 1171 1172 1173 1174
		prealloc = NULL;
		if (err)
			goto out;
		if (state->end <= end) {
			set_state_bits(tree, state, &bits);
1175
			cache_state(state, cached_state);
1176
			state = clear_state_bit(tree, state, &clear_bits, 0);
J
Josef Bacik 已提交
1177 1178 1179
			if (last_end == (u64)-1)
				goto out;
			start = last_end + 1;
1180 1181 1182
			if (start < end && state && state->start == start &&
			    !need_resched())
				goto hit_next;
J
Josef Bacik 已提交
1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200
		}
		goto search_again;
	}
	/*
	 * | ---- desired range ---- |
	 *     | state | or               | state |
	 *
	 * There's a hole, we need to insert something in it and
	 * ignore the extent we found.
	 */
	if (state->start > start) {
		u64 this_end;
		if (end < last_start)
			this_end = end;
		else
			this_end = last_start - 1;

		prealloc = alloc_extent_state_atomic(prealloc);
1201 1202 1203 1204
		if (!prealloc) {
			err = -ENOMEM;
			goto out;
		}
J
Josef Bacik 已提交
1205 1206 1207 1208 1209 1210

		/*
		 * Avoid to free 'prealloc' if it can be merged with
		 * the later extent.
		 */
		err = insert_state(tree, prealloc, start, this_end,
1211
				   NULL, NULL, &bits);
1212 1213
		if (err)
			extent_io_tree_panic(tree, err);
1214
		cache_state(prealloc, cached_state);
J
Josef Bacik 已提交
1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226
		prealloc = NULL;
		start = this_end + 1;
		goto search_again;
	}
	/*
	 * | ---- desired range ---- |
	 *                        | state |
	 * We need to split the extent, and set the bit
	 * on the first half
	 */
	if (state->start <= end && state->end > end) {
		prealloc = alloc_extent_state_atomic(prealloc);
1227 1228 1229 1230
		if (!prealloc) {
			err = -ENOMEM;
			goto out;
		}
J
Josef Bacik 已提交
1231 1232

		err = split_state(tree, state, prealloc, end + 1);
1233 1234
		if (err)
			extent_io_tree_panic(tree, err);
J
Josef Bacik 已提交
1235 1236

		set_state_bits(tree, prealloc, &bits);
1237
		cache_state(prealloc, cached_state);
J
Josef Bacik 已提交
1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257
		clear_state_bit(tree, prealloc, &clear_bits, 0);
		prealloc = NULL;
		goto out;
	}

	goto search_again;

out:
	spin_unlock(&tree->lock);
	if (prealloc)
		free_extent_state(prealloc);

	return err;

search_again:
	if (start > end)
		goto out;
	spin_unlock(&tree->lock);
	if (mask & __GFP_WAIT)
		cond_resched();
1258
	first_iteration = false;
J
Josef Bacik 已提交
1259 1260 1261
	goto again;
}

1262 1263 1264 1265
/* wrappers around set/clear extent bit */
int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
		     gfp_t mask)
{
J
Jeff Mahoney 已提交
1266
	return set_extent_bit(tree, start, end, EXTENT_DIRTY, NULL,
1267
			      NULL, mask);
1268 1269 1270
}

int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1271
		    unsigned bits, gfp_t mask)
1272
{
J
Jeff Mahoney 已提交
1273
	return set_extent_bit(tree, start, end, bits, NULL,
1274
			      NULL, mask);
1275 1276 1277
}

int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1278
		      unsigned bits, gfp_t mask)
1279
{
1280 1281 1282 1283 1284 1285
	int wake = 0;

	if (bits & EXTENT_LOCKED)
		wake = 1;

	return clear_extent_bit(tree, start, end, bits, wake, 0, NULL, mask);
1286 1287 1288
}

int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
1289
			struct extent_state **cached_state, gfp_t mask)
1290 1291
{
	return set_extent_bit(tree, start, end,
1292
			      EXTENT_DELALLOC | EXTENT_UPTODATE,
J
Jeff Mahoney 已提交
1293
			      NULL, cached_state, mask);
1294 1295
}

1296 1297 1298 1299 1300 1301 1302 1303
int set_extent_defrag(struct extent_io_tree *tree, u64 start, u64 end,
		      struct extent_state **cached_state, gfp_t mask)
{
	return set_extent_bit(tree, start, end,
			      EXTENT_DELALLOC | EXTENT_UPTODATE | EXTENT_DEFRAG,
			      NULL, cached_state, mask);
}

1304 1305 1306 1307
int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
		       gfp_t mask)
{
	return clear_extent_bit(tree, start, end,
1308
				EXTENT_DIRTY | EXTENT_DELALLOC |
1309
				EXTENT_DO_ACCOUNTING, 0, 0, NULL, mask);
1310 1311 1312 1313 1314
}

int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
		     gfp_t mask)
{
J
Jeff Mahoney 已提交
1315
	return set_extent_bit(tree, start, end, EXTENT_NEW, NULL,
1316
			      NULL, mask);
1317 1318 1319
}

int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
1320
			struct extent_state **cached_state, gfp_t mask)
1321
{
L
Liu Bo 已提交
1322
	return set_extent_bit(tree, start, end, EXTENT_UPTODATE, NULL,
J
Jeff Mahoney 已提交
1323
			      cached_state, mask);
1324 1325
}

1326 1327
int clear_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
			  struct extent_state **cached_state, gfp_t mask)
1328
{
1329
	return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
1330
				cached_state, mask);
1331 1332
}

C
Chris Mason 已提交
1333 1334 1335 1336
/*
 * either insert or lock state struct between start and end use mask to tell
 * us if waiting is desired.
 */
1337
int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1338
		     unsigned bits, struct extent_state **cached_state)
1339 1340 1341
{
	int err;
	u64 failed_start;
1342

1343
	while (1) {
J
Jeff Mahoney 已提交
1344 1345 1346
		err = __set_extent_bit(tree, start, end, EXTENT_LOCKED | bits,
				       EXTENT_LOCKED, &failed_start,
				       cached_state, GFP_NOFS);
1347
		if (err == -EEXIST) {
1348 1349
			wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
			start = failed_start;
1350
		} else
1351 1352 1353 1354 1355 1356
			break;
		WARN_ON(start > end);
	}
	return err;
}

1357
int lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1358
{
1359
	return lock_extent_bits(tree, start, end, 0, NULL);
1360 1361
}

1362
int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1363 1364 1365 1366
{
	int err;
	u64 failed_start;

J
Jeff Mahoney 已提交
1367 1368
	err = __set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
			       &failed_start, NULL, GFP_NOFS);
Y
Yan Zheng 已提交
1369 1370 1371
	if (err == -EEXIST) {
		if (failed_start > start)
			clear_extent_bit(tree, start, failed_start - 1,
1372
					 EXTENT_LOCKED, 1, 0, NULL, GFP_NOFS);
1373
		return 0;
Y
Yan Zheng 已提交
1374
	}
1375 1376 1377
	return 1;
}

1378 1379 1380 1381 1382 1383 1384
int unlock_extent_cached(struct extent_io_tree *tree, u64 start, u64 end,
			 struct extent_state **cached, gfp_t mask)
{
	return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
				mask);
}

1385
int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1386
{
1387
	return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
1388
				GFP_NOFS);
1389 1390
}

1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416
int extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end)
{
	unsigned long index = start >> PAGE_CACHE_SHIFT;
	unsigned long end_index = end >> PAGE_CACHE_SHIFT;
	struct page *page;

	while (index <= end_index) {
		page = find_get_page(inode->i_mapping, index);
		BUG_ON(!page); /* Pages should be in the extent_io_tree */
		clear_page_dirty_for_io(page);
		page_cache_release(page);
		index++;
	}
	return 0;
}

int extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end)
{
	unsigned long index = start >> PAGE_CACHE_SHIFT;
	unsigned long end_index = end >> PAGE_CACHE_SHIFT;
	struct page *page;

	while (index <= end_index) {
		page = find_get_page(inode->i_mapping, index);
		BUG_ON(!page); /* Pages should be in the extent_io_tree */
		__set_page_dirty_nobuffers(page);
1417
		account_page_redirty(page);
1418 1419 1420 1421 1422 1423
		page_cache_release(page);
		index++;
	}
	return 0;
}

1424 1425 1426
/*
 * helper function to set both pages and extents in the tree writeback
 */
1427
static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1428 1429 1430 1431 1432 1433 1434
{
	unsigned long index = start >> PAGE_CACHE_SHIFT;
	unsigned long end_index = end >> PAGE_CACHE_SHIFT;
	struct page *page;

	while (index <= end_index) {
		page = find_get_page(tree->mapping, index);
1435
		BUG_ON(!page); /* Pages should be in the extent_io_tree */
1436 1437 1438 1439 1440 1441 1442
		set_page_writeback(page);
		page_cache_release(page);
		index++;
	}
	return 0;
}

C
Chris Mason 已提交
1443 1444 1445 1446
/* find the first state struct with 'bits' set after 'start', and
 * return it.  tree->lock must be held.  NULL will returned if
 * nothing was found after 'start'
 */
1447 1448
static struct extent_state *
find_first_extent_bit_state(struct extent_io_tree *tree,
1449
			    u64 start, unsigned bits)
C
Chris Mason 已提交
1450 1451 1452 1453 1454 1455 1456 1457 1458
{
	struct rb_node *node;
	struct extent_state *state;

	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
	node = tree_search(tree, start);
C
Chris Mason 已提交
1459
	if (!node)
C
Chris Mason 已提交
1460 1461
		goto out;

C
Chris Mason 已提交
1462
	while (1) {
C
Chris Mason 已提交
1463
		state = rb_entry(node, struct extent_state, rb_node);
C
Chris Mason 已提交
1464
		if (state->end >= start && (state->state & bits))
C
Chris Mason 已提交
1465
			return state;
C
Chris Mason 已提交
1466

C
Chris Mason 已提交
1467 1468 1469 1470 1471 1472 1473 1474
		node = rb_next(node);
		if (!node)
			break;
	}
out:
	return NULL;
}

1475 1476 1477 1478 1479
/*
 * find the first offset in the io tree with 'bits' set. zero is
 * returned if we find something, and *start_ret and *end_ret are
 * set to reflect the state struct that was found.
 *
1480
 * If nothing was found, 1 is returned. If found something, return 0.
1481 1482
 */
int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1483
			  u64 *start_ret, u64 *end_ret, unsigned bits,
1484
			  struct extent_state **cached_state)
1485 1486
{
	struct extent_state *state;
1487
	struct rb_node *n;
1488 1489 1490
	int ret = 1;

	spin_lock(&tree->lock);
1491 1492
	if (cached_state && *cached_state) {
		state = *cached_state;
1493
		if (state->end == start - 1 && extent_state_in_tree(state)) {
1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509
			n = rb_next(&state->rb_node);
			while (n) {
				state = rb_entry(n, struct extent_state,
						 rb_node);
				if (state->state & bits)
					goto got_it;
				n = rb_next(n);
			}
			free_extent_state(*cached_state);
			*cached_state = NULL;
			goto out;
		}
		free_extent_state(*cached_state);
		*cached_state = NULL;
	}

1510
	state = find_first_extent_bit_state(tree, start, bits);
1511
got_it:
1512
	if (state) {
1513
		cache_state_if_flags(state, cached_state, 0);
1514 1515 1516 1517
		*start_ret = state->start;
		*end_ret = state->end;
		ret = 0;
	}
1518
out:
1519 1520 1521 1522
	spin_unlock(&tree->lock);
	return ret;
}

C
Chris Mason 已提交
1523 1524 1525 1526 1527 1528
/*
 * find a contiguous range of bytes in the file marked as delalloc, not
 * more than 'max_bytes'.  start and end are used to return the range,
 *
 * 1 is returned if we find something, 0 if nothing was in the tree
 */
C
Chris Mason 已提交
1529
static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1530 1531
					u64 *start, u64 *end, u64 max_bytes,
					struct extent_state **cached_state)
1532 1533 1534 1535 1536 1537 1538
{
	struct rb_node *node;
	struct extent_state *state;
	u64 cur_start = *start;
	u64 found = 0;
	u64 total_bytes = 0;

1539
	spin_lock(&tree->lock);
C
Chris Mason 已提交
1540

1541 1542 1543 1544
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1545
	node = tree_search(tree, cur_start);
1546
	if (!node) {
1547 1548
		if (!found)
			*end = (u64)-1;
1549 1550 1551
		goto out;
	}

C
Chris Mason 已提交
1552
	while (1) {
1553
		state = rb_entry(node, struct extent_state, rb_node);
1554 1555
		if (found && (state->start != cur_start ||
			      (state->state & EXTENT_BOUNDARY))) {
1556 1557 1558 1559 1560 1561 1562
			goto out;
		}
		if (!(state->state & EXTENT_DELALLOC)) {
			if (!found)
				*end = state->end;
			goto out;
		}
1563
		if (!found) {
1564
			*start = state->start;
1565 1566 1567
			*cached_state = state;
			atomic_inc(&state->refs);
		}
1568 1569 1570 1571 1572
		found++;
		*end = state->end;
		cur_start = state->end + 1;
		node = rb_next(node);
		total_bytes += state->end - state->start + 1;
1573
		if (total_bytes >= max_bytes)
1574 1575
			break;
		if (!node)
1576 1577 1578
			break;
	}
out:
1579
	spin_unlock(&tree->lock);
1580 1581 1582
	return found;
}

1583 1584 1585
static noinline void __unlock_for_delalloc(struct inode *inode,
					   struct page *locked_page,
					   u64 start, u64 end)
C
Chris Mason 已提交
1586 1587 1588 1589 1590 1591 1592 1593 1594
{
	int ret;
	struct page *pages[16];
	unsigned long index = start >> PAGE_CACHE_SHIFT;
	unsigned long end_index = end >> PAGE_CACHE_SHIFT;
	unsigned long nr_pages = end_index - index + 1;
	int i;

	if (index == locked_page->index && end_index == index)
1595
		return;
C
Chris Mason 已提交
1596

C
Chris Mason 已提交
1597
	while (nr_pages > 0) {
C
Chris Mason 已提交
1598
		ret = find_get_pages_contig(inode->i_mapping, index,
1599 1600
				     min_t(unsigned long, nr_pages,
				     ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631
		for (i = 0; i < ret; i++) {
			if (pages[i] != locked_page)
				unlock_page(pages[i]);
			page_cache_release(pages[i]);
		}
		nr_pages -= ret;
		index += ret;
		cond_resched();
	}
}

static noinline int lock_delalloc_pages(struct inode *inode,
					struct page *locked_page,
					u64 delalloc_start,
					u64 delalloc_end)
{
	unsigned long index = delalloc_start >> PAGE_CACHE_SHIFT;
	unsigned long start_index = index;
	unsigned long end_index = delalloc_end >> PAGE_CACHE_SHIFT;
	unsigned long pages_locked = 0;
	struct page *pages[16];
	unsigned long nrpages;
	int ret;
	int i;

	/* the caller is responsible for locking the start index */
	if (index == locked_page->index && index == end_index)
		return 0;

	/* skip the page at the start index */
	nrpages = end_index - index + 1;
C
Chris Mason 已提交
1632
	while (nrpages > 0) {
C
Chris Mason 已提交
1633
		ret = find_get_pages_contig(inode->i_mapping, index,
1634 1635
				     min_t(unsigned long,
				     nrpages, ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1636 1637 1638 1639 1640 1641 1642 1643 1644 1645
		if (ret == 0) {
			ret = -EAGAIN;
			goto done;
		}
		/* now we have an array of pages, lock them all */
		for (i = 0; i < ret; i++) {
			/*
			 * the caller is taking responsibility for
			 * locked_page
			 */
1646
			if (pages[i] != locked_page) {
C
Chris Mason 已提交
1647
				lock_page(pages[i]);
1648 1649
				if (!PageDirty(pages[i]) ||
				    pages[i]->mapping != inode->i_mapping) {
1650 1651 1652 1653 1654 1655
					ret = -EAGAIN;
					unlock_page(pages[i]);
					page_cache_release(pages[i]);
					goto done;
				}
			}
C
Chris Mason 已提交
1656
			page_cache_release(pages[i]);
1657
			pages_locked++;
C
Chris Mason 已提交
1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679
		}
		nrpages -= ret;
		index += ret;
		cond_resched();
	}
	ret = 0;
done:
	if (ret && pages_locked) {
		__unlock_for_delalloc(inode, locked_page,
			      delalloc_start,
			      ((u64)(start_index + pages_locked - 1)) <<
			      PAGE_CACHE_SHIFT);
	}
	return ret;
}

/*
 * find a contiguous range of bytes in the file marked as delalloc, not
 * more than 'max_bytes'.  start and end are used to return the range,
 *
 * 1 is returned if we find something, 0 if nothing was in the tree
 */
1680 1681 1682 1683
STATIC u64 find_lock_delalloc_range(struct inode *inode,
				    struct extent_io_tree *tree,
				    struct page *locked_page, u64 *start,
				    u64 *end, u64 max_bytes)
C
Chris Mason 已提交
1684 1685 1686 1687
{
	u64 delalloc_start;
	u64 delalloc_end;
	u64 found;
1688
	struct extent_state *cached_state = NULL;
C
Chris Mason 已提交
1689 1690 1691 1692 1693 1694 1695 1696
	int ret;
	int loops = 0;

again:
	/* step one, find a bunch of delalloc bytes starting at start */
	delalloc_start = *start;
	delalloc_end = 0;
	found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
1697
				    max_bytes, &cached_state);
C
Chris Mason 已提交
1698
	if (!found || delalloc_end <= *start) {
C
Chris Mason 已提交
1699 1700
		*start = delalloc_start;
		*end = delalloc_end;
1701
		free_extent_state(cached_state);
L
Liu Bo 已提交
1702
		return 0;
C
Chris Mason 已提交
1703 1704
	}

C
Chris Mason 已提交
1705 1706 1707 1708 1709
	/*
	 * start comes from the offset of locked_page.  We have to lock
	 * pages in order, so we can't process delalloc bytes before
	 * locked_page
	 */
C
Chris Mason 已提交
1710
	if (delalloc_start < *start)
C
Chris Mason 已提交
1711 1712
		delalloc_start = *start;

C
Chris Mason 已提交
1713 1714 1715
	/*
	 * make sure to limit the number of pages we try to lock down
	 */
1716 1717
	if (delalloc_end + 1 - delalloc_start > max_bytes)
		delalloc_end = delalloc_start + max_bytes - 1;
C
Chris Mason 已提交
1718

C
Chris Mason 已提交
1719 1720 1721 1722 1723 1724 1725
	/* step two, lock all the pages after the page that has start */
	ret = lock_delalloc_pages(inode, locked_page,
				  delalloc_start, delalloc_end);
	if (ret == -EAGAIN) {
		/* some of the pages are gone, lets avoid looping by
		 * shortening the size of the delalloc range we're searching
		 */
1726
		free_extent_state(cached_state);
1727
		cached_state = NULL;
C
Chris Mason 已提交
1728
		if (!loops) {
1729
			max_bytes = PAGE_CACHE_SIZE;
C
Chris Mason 已提交
1730 1731 1732 1733 1734 1735 1736
			loops = 1;
			goto again;
		} else {
			found = 0;
			goto out_failed;
		}
	}
1737
	BUG_ON(ret); /* Only valid values are 0 and -EAGAIN */
C
Chris Mason 已提交
1738 1739

	/* step three, lock the state bits for the whole range */
1740
	lock_extent_bits(tree, delalloc_start, delalloc_end, 0, &cached_state);
C
Chris Mason 已提交
1741 1742 1743

	/* then test to make sure it is all still delalloc */
	ret = test_range_bit(tree, delalloc_start, delalloc_end,
1744
			     EXTENT_DELALLOC, 1, cached_state);
C
Chris Mason 已提交
1745
	if (!ret) {
1746 1747
		unlock_extent_cached(tree, delalloc_start, delalloc_end,
				     &cached_state, GFP_NOFS);
C
Chris Mason 已提交
1748 1749 1750 1751 1752
		__unlock_for_delalloc(inode, locked_page,
			      delalloc_start, delalloc_end);
		cond_resched();
		goto again;
	}
1753
	free_extent_state(cached_state);
C
Chris Mason 已提交
1754 1755 1756 1757 1758 1759
	*start = delalloc_start;
	*end = delalloc_end;
out_failed:
	return found;
}

1760 1761
int extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
				 struct page *locked_page,
1762
				 unsigned clear_bits,
1763
				 unsigned long page_ops)
C
Chris Mason 已提交
1764
{
1765
	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
C
Chris Mason 已提交
1766 1767 1768 1769 1770 1771
	int ret;
	struct page *pages[16];
	unsigned long index = start >> PAGE_CACHE_SHIFT;
	unsigned long end_index = end >> PAGE_CACHE_SHIFT;
	unsigned long nr_pages = end_index - index + 1;
	int i;
1772

1773
	clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1774
	if (page_ops == 0)
1775
		return 0;
C
Chris Mason 已提交
1776

1777 1778 1779
	if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
		mapping_set_error(inode->i_mapping, -EIO);

C
Chris Mason 已提交
1780
	while (nr_pages > 0) {
C
Chris Mason 已提交
1781
		ret = find_get_pages_contig(inode->i_mapping, index,
1782 1783
				     min_t(unsigned long,
				     nr_pages, ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1784
		for (i = 0; i < ret; i++) {
1785

1786
			if (page_ops & PAGE_SET_PRIVATE2)
1787 1788
				SetPagePrivate2(pages[i]);

C
Chris Mason 已提交
1789 1790 1791 1792
			if (pages[i] == locked_page) {
				page_cache_release(pages[i]);
				continue;
			}
1793
			if (page_ops & PAGE_CLEAR_DIRTY)
C
Chris Mason 已提交
1794
				clear_page_dirty_for_io(pages[i]);
1795
			if (page_ops & PAGE_SET_WRITEBACK)
C
Chris Mason 已提交
1796
				set_page_writeback(pages[i]);
1797 1798
			if (page_ops & PAGE_SET_ERROR)
				SetPageError(pages[i]);
1799
			if (page_ops & PAGE_END_WRITEBACK)
C
Chris Mason 已提交
1800
				end_page_writeback(pages[i]);
1801
			if (page_ops & PAGE_UNLOCK)
1802
				unlock_page(pages[i]);
C
Chris Mason 已提交
1803 1804 1805 1806 1807 1808 1809 1810 1811
			page_cache_release(pages[i]);
		}
		nr_pages -= ret;
		index += ret;
		cond_resched();
	}
	return 0;
}

C
Chris Mason 已提交
1812 1813 1814 1815 1816
/*
 * count the number of bytes in the tree that have a given bit(s)
 * set.  This can be fairly slow, except for EXTENT_DIRTY which is
 * cached.  The total number found is returned.
 */
1817 1818
u64 count_range_bits(struct extent_io_tree *tree,
		     u64 *start, u64 search_end, u64 max_bytes,
1819
		     unsigned bits, int contig)
1820 1821 1822 1823 1824
{
	struct rb_node *node;
	struct extent_state *state;
	u64 cur_start = *start;
	u64 total_bytes = 0;
1825
	u64 last = 0;
1826 1827
	int found = 0;

1828
	if (WARN_ON(search_end <= cur_start))
1829 1830
		return 0;

1831
	spin_lock(&tree->lock);
1832 1833 1834 1835 1836 1837 1838 1839
	if (cur_start == 0 && bits == EXTENT_DIRTY) {
		total_bytes = tree->dirty_bytes;
		goto out;
	}
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1840
	node = tree_search(tree, cur_start);
C
Chris Mason 已提交
1841
	if (!node)
1842 1843
		goto out;

C
Chris Mason 已提交
1844
	while (1) {
1845 1846 1847
		state = rb_entry(node, struct extent_state, rb_node);
		if (state->start > search_end)
			break;
1848 1849 1850
		if (contig && found && state->start > last + 1)
			break;
		if (state->end >= cur_start && (state->state & bits) == bits) {
1851 1852 1853 1854 1855
			total_bytes += min(search_end, state->end) + 1 -
				       max(cur_start, state->start);
			if (total_bytes >= max_bytes)
				break;
			if (!found) {
1856
				*start = max(cur_start, state->start);
1857 1858
				found = 1;
			}
1859 1860 1861
			last = state->end;
		} else if (contig && found) {
			break;
1862 1863 1864 1865 1866 1867
		}
		node = rb_next(node);
		if (!node)
			break;
	}
out:
1868
	spin_unlock(&tree->lock);
1869 1870
	return total_bytes;
}
1871

C
Chris Mason 已提交
1872 1873 1874 1875
/*
 * set the private field for a given byte offset in the tree.  If there isn't
 * an extent_state there already, this does nothing.
 */
1876
static int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
1877 1878 1879 1880 1881
{
	struct rb_node *node;
	struct extent_state *state;
	int ret = 0;

1882
	spin_lock(&tree->lock);
1883 1884 1885 1886
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1887
	node = tree_search(tree, start);
1888
	if (!node) {
1889 1890 1891 1892 1893 1894 1895 1896 1897 1898
		ret = -ENOENT;
		goto out;
	}
	state = rb_entry(node, struct extent_state, rb_node);
	if (state->start != start) {
		ret = -ENOENT;
		goto out;
	}
	state->private = private;
out:
1899
	spin_unlock(&tree->lock);
1900 1901 1902 1903 1904 1905 1906 1907 1908
	return ret;
}

int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
{
	struct rb_node *node;
	struct extent_state *state;
	int ret = 0;

1909
	spin_lock(&tree->lock);
1910 1911 1912 1913
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1914
	node = tree_search(tree, start);
1915
	if (!node) {
1916 1917 1918 1919 1920 1921 1922 1923 1924 1925
		ret = -ENOENT;
		goto out;
	}
	state = rb_entry(node, struct extent_state, rb_node);
	if (state->start != start) {
		ret = -ENOENT;
		goto out;
	}
	*private = state->private;
out:
1926
	spin_unlock(&tree->lock);
1927 1928 1929 1930 1931
	return ret;
}

/*
 * searches a range in the state tree for a given mask.
1932
 * If 'filled' == 1, this returns 1 only if every extent in the tree
1933 1934 1935 1936
 * has the bits set.  Otherwise, 1 is returned if any bit in the
 * range is found set.
 */
int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
1937
		   unsigned bits, int filled, struct extent_state *cached)
1938 1939 1940 1941 1942
{
	struct extent_state *state = NULL;
	struct rb_node *node;
	int bitset = 0;

1943
	spin_lock(&tree->lock);
1944
	if (cached && extent_state_in_tree(cached) && cached->start <= start &&
1945
	    cached->end > start)
1946 1947 1948
		node = &cached->rb_node;
	else
		node = tree_search(tree, start);
1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967
	while (node && start <= end) {
		state = rb_entry(node, struct extent_state, rb_node);

		if (filled && state->start > start) {
			bitset = 0;
			break;
		}

		if (state->start > end)
			break;

		if (state->state & bits) {
			bitset = 1;
			if (!filled)
				break;
		} else if (filled) {
			bitset = 0;
			break;
		}
1968 1969 1970 1971

		if (state->end == (u64)-1)
			break;

1972 1973 1974 1975 1976 1977 1978 1979 1980 1981
		start = state->end + 1;
		if (start > end)
			break;
		node = rb_next(node);
		if (!node) {
			if (filled)
				bitset = 0;
			break;
		}
	}
1982
	spin_unlock(&tree->lock);
1983 1984 1985 1986 1987 1988 1989
	return bitset;
}

/*
 * helper function to set a given page up to date if all the
 * extents in the tree for that page are up to date
 */
1990
static void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
1991
{
M
Miao Xie 已提交
1992
	u64 start = page_offset(page);
1993
	u64 end = start + PAGE_CACHE_SIZE - 1;
1994
	if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1995 1996 1997
		SetPageUptodate(page);
}

1998
int free_io_failure(struct inode *inode, struct io_failure_record *rec)
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
{
	int ret;
	int err = 0;
	struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;

	set_state_private(failure_tree, rec->start, 0);
	ret = clear_extent_bits(failure_tree, rec->start,
				rec->start + rec->len - 1,
				EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
	if (ret)
		err = ret;

D
David Woodhouse 已提交
2011 2012 2013 2014 2015
	ret = clear_extent_bits(&BTRFS_I(inode)->io_tree, rec->start,
				rec->start + rec->len - 1,
				EXTENT_DAMAGED, GFP_NOFS);
	if (ret && !err)
		err = ret;
2016 2017 2018 2019 2020 2021 2022 2023 2024 2025

	kfree(rec);
	return err;
}

/*
 * this bypasses the standard btrfs submit functions deliberately, as
 * the standard behavior is to write all copies in a raid setup. here we only
 * want to write the one bad copy. so we do the mapping for ourselves and issue
 * submit_bio directly.
2026
 * to avoid any synchronization issues, wait for the data after writing, which
2027 2028 2029 2030
 * actually prevents the read that triggered the error from finishing.
 * currently, there can be no more than two copies of every data bit. thus,
 * exactly one rewrite is required.
 */
2031 2032
int repair_io_failure(struct inode *inode, u64 start, u64 length, u64 logical,
		      struct page *page, unsigned int pg_offset, int mirror_num)
2033
{
2034
	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2035 2036 2037 2038 2039
	struct bio *bio;
	struct btrfs_device *dev;
	u64 map_length = 0;
	u64 sector;
	struct btrfs_bio *bbio = NULL;
D
David Woodhouse 已提交
2040
	struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
2041 2042
	int ret;

2043
	ASSERT(!(fs_info->sb->s_flags & MS_RDONLY));
2044 2045
	BUG_ON(!mirror_num);

D
David Woodhouse 已提交
2046 2047 2048 2049
	/* we can't repair anything in raid56 yet */
	if (btrfs_is_parity_mirror(map_tree, logical, length, mirror_num))
		return 0;

2050
	bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2051 2052
	if (!bio)
		return -EIO;
2053
	bio->bi_iter.bi_size = 0;
2054 2055
	map_length = length;

2056
	ret = btrfs_map_block(fs_info, WRITE, logical,
2057 2058 2059 2060 2061 2062 2063
			      &map_length, &bbio, mirror_num);
	if (ret) {
		bio_put(bio);
		return -EIO;
	}
	BUG_ON(mirror_num != bbio->mirror_num);
	sector = bbio->stripes[mirror_num-1].physical >> 9;
2064
	bio->bi_iter.bi_sector = sector;
2065
	dev = bbio->stripes[mirror_num-1].dev;
2066
	btrfs_put_bbio(bbio);
2067 2068 2069 2070 2071
	if (!dev || !dev->bdev || !dev->writeable) {
		bio_put(bio);
		return -EIO;
	}
	bio->bi_bdev = dev->bdev;
2072
	bio_add_page(bio, page, length, pg_offset);
2073

2074
	if (btrfsic_submit_bio_wait(WRITE_SYNC, bio)) {
2075 2076
		/* try to remap that extent elsewhere? */
		bio_put(bio);
2077
		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
2078 2079 2080
		return -EIO;
	}

2081
	printk_ratelimited_in_rcu(KERN_INFO
2082 2083 2084
				  "BTRFS: read error corrected: ino %llu off %llu (dev %s sector %llu)\n",
				  btrfs_ino(inode), start,
				  rcu_str_deref(dev->name), sector);
2085 2086 2087 2088
	bio_put(bio);
	return 0;
}

2089 2090 2091 2092 2093
int repair_eb_io_failure(struct btrfs_root *root, struct extent_buffer *eb,
			 int mirror_num)
{
	u64 start = eb->start;
	unsigned long i, num_pages = num_extent_pages(eb->start, eb->len);
2094
	int ret = 0;
2095

2096 2097 2098
	if (root->fs_info->sb->s_flags & MS_RDONLY)
		return -EROFS;

2099
	for (i = 0; i < num_pages; i++) {
2100
		struct page *p = eb->pages[i];
2101 2102 2103 2104

		ret = repair_io_failure(root->fs_info->btree_inode, start,
					PAGE_CACHE_SIZE, start, p,
					start - page_offset(p), mirror_num);
2105 2106 2107 2108 2109 2110 2111 2112
		if (ret)
			break;
		start += PAGE_CACHE_SIZE;
	}

	return ret;
}

2113 2114 2115 2116
/*
 * each time an IO finishes, we do a fast check in the IO failure tree
 * to see if we need to process or clean up an io_failure_record
 */
2117 2118
int clean_io_failure(struct inode *inode, u64 start, struct page *page,
		     unsigned int pg_offset)
2119 2120 2121 2122
{
	u64 private;
	u64 private_failure;
	struct io_failure_record *failrec;
2123
	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147
	struct extent_state *state;
	int num_copies;
	int ret;

	private = 0;
	ret = count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
				(u64)-1, 1, EXTENT_DIRTY, 0);
	if (!ret)
		return 0;

	ret = get_state_private(&BTRFS_I(inode)->io_failure_tree, start,
				&private_failure);
	if (ret)
		return 0;

	failrec = (struct io_failure_record *)(unsigned long) private_failure;
	BUG_ON(!failrec->this_mirror);

	if (failrec->in_validation) {
		/* there was no real error, just free the record */
		pr_debug("clean_io_failure: freeing dummy error at %llu\n",
			 failrec->start);
		goto out;
	}
2148 2149
	if (fs_info->sb->s_flags & MS_RDONLY)
		goto out;
2150 2151 2152 2153 2154 2155 2156

	spin_lock(&BTRFS_I(inode)->io_tree.lock);
	state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
					    failrec->start,
					    EXTENT_LOCKED);
	spin_unlock(&BTRFS_I(inode)->io_tree.lock);

2157 2158
	if (state && state->start <= failrec->start &&
	    state->end >= failrec->start + failrec->len - 1) {
2159 2160
		num_copies = btrfs_num_copies(fs_info, failrec->logical,
					      failrec->len);
2161
		if (num_copies > 1)  {
2162
			repair_io_failure(inode, start, failrec->len,
2163
					  failrec->logical, page,
2164
					  pg_offset, failrec->failed_mirror);
2165 2166 2167 2168
		}
	}

out:
2169
	free_io_failure(inode, failrec);
2170

2171
	return 0;
2172 2173
}

2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198
/*
 * Can be called when
 * - hold extent lock
 * - under ordered extent
 * - the inode is freeing
 */
void btrfs_free_io_failure_record(struct inode *inode, u64 start, u64 end)
{
	struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
	struct io_failure_record *failrec;
	struct extent_state *state, *next;

	if (RB_EMPTY_ROOT(&failure_tree->state))
		return;

	spin_lock(&failure_tree->lock);
	state = find_first_extent_bit_state(failure_tree, start, EXTENT_DIRTY);
	while (state) {
		if (state->start > end)
			break;

		ASSERT(state->end <= end);

		next = next_state(state);

2199
		failrec = (struct io_failure_record *)(unsigned long)state->private;
2200 2201 2202 2203 2204 2205 2206 2207
		free_extent_state(state);
		kfree(failrec);

		state = next;
	}
	spin_unlock(&failure_tree->lock);
}

2208 2209
int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
				struct io_failure_record **failrec_ret)
2210
{
2211
	struct io_failure_record *failrec;
2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224
	u64 private;
	struct extent_map *em;
	struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
	int ret;
	u64 logical;

	ret = get_state_private(failure_tree, start, &private);
	if (ret) {
		failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
		if (!failrec)
			return -ENOMEM;
2225

2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239
		failrec->start = start;
		failrec->len = end - start + 1;
		failrec->this_mirror = 0;
		failrec->bio_flags = 0;
		failrec->in_validation = 0;

		read_lock(&em_tree->lock);
		em = lookup_extent_mapping(em_tree, start, failrec->len);
		if (!em) {
			read_unlock(&em_tree->lock);
			kfree(failrec);
			return -EIO;
		}

2240
		if (em->start > start || em->start + em->len <= start) {
2241 2242 2243 2244
			free_extent_map(em);
			em = NULL;
		}
		read_unlock(&em_tree->lock);
2245
		if (!em) {
2246 2247 2248
			kfree(failrec);
			return -EIO;
		}
2249

2250 2251 2252 2253 2254 2255 2256 2257
		logical = start - em->start;
		logical = em->block_start + logical;
		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
			logical = em->block_start;
			failrec->bio_flags = EXTENT_BIO_COMPRESSED;
			extent_set_compress_type(&failrec->bio_flags,
						 em->compress_type);
		}
2258 2259 2260 2261

		pr_debug("Get IO Failure Record: (new) logical=%llu, start=%llu, len=%llu\n",
			 logical, start, failrec->len);

2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280
		failrec->logical = logical;
		free_extent_map(em);

		/* set the bits in the private failure tree */
		ret = set_extent_bits(failure_tree, start, end,
					EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
		if (ret >= 0)
			ret = set_state_private(failure_tree, start,
						(u64)(unsigned long)failrec);
		/* set the bits in the inode's tree */
		if (ret >= 0)
			ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED,
						GFP_NOFS);
		if (ret < 0) {
			kfree(failrec);
			return ret;
		}
	} else {
		failrec = (struct io_failure_record *)(unsigned long)private;
2281
		pr_debug("Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu, validation=%d\n",
2282 2283 2284 2285 2286 2287 2288 2289
			 failrec->logical, failrec->start, failrec->len,
			 failrec->in_validation);
		/*
		 * when data can be on disk more than twice, add to failrec here
		 * (e.g. with a list for failed_mirror) to make
		 * clean_io_failure() clean all those errors at once.
		 */
	}
2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300

	*failrec_ret = failrec;

	return 0;
}

int btrfs_check_repairable(struct inode *inode, struct bio *failed_bio,
			   struct io_failure_record *failrec, int failed_mirror)
{
	int num_copies;

2301 2302
	num_copies = btrfs_num_copies(BTRFS_I(inode)->root->fs_info,
				      failrec->logical, failrec->len);
2303 2304 2305 2306 2307 2308
	if (num_copies == 1) {
		/*
		 * we only have a single copy of the data, so don't bother with
		 * all the retry and error correction code that follows. no
		 * matter what the error is, it is very likely to persist.
		 */
2309
		pr_debug("Check Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d\n",
2310
			 num_copies, failrec->this_mirror, failed_mirror);
2311
		return 0;
2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347
	}

	/*
	 * there are two premises:
	 *	a) deliver good data to the caller
	 *	b) correct the bad sectors on disk
	 */
	if (failed_bio->bi_vcnt > 1) {
		/*
		 * to fulfill b), we need to know the exact failing sectors, as
		 * we don't want to rewrite any more than the failed ones. thus,
		 * we need separate read requests for the failed bio
		 *
		 * if the following BUG_ON triggers, our validation request got
		 * merged. we need separate requests for our algorithm to work.
		 */
		BUG_ON(failrec->in_validation);
		failrec->in_validation = 1;
		failrec->this_mirror = failed_mirror;
	} else {
		/*
		 * we're ready to fulfill a) and b) alongside. get a good copy
		 * of the failed sector and if we succeed, we have setup
		 * everything for repair_io_failure to do the rest for us.
		 */
		if (failrec->in_validation) {
			BUG_ON(failrec->this_mirror != failed_mirror);
			failrec->in_validation = 0;
			failrec->this_mirror = 0;
		}
		failrec->failed_mirror = failed_mirror;
		failrec->this_mirror++;
		if (failrec->this_mirror == failed_mirror)
			failrec->this_mirror++;
	}

2348
	if (failrec->this_mirror > num_copies) {
2349
		pr_debug("Check Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d\n",
2350
			 num_copies, failrec->this_mirror, failed_mirror);
2351
		return 0;
2352 2353
	}

2354 2355 2356 2357 2358 2359 2360
	return 1;
}


struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
				    struct io_failure_record *failrec,
				    struct page *page, int pg_offset, int icsum,
2361
				    bio_end_io_t *endio_func, void *data)
2362 2363 2364 2365 2366
{
	struct bio *bio;
	struct btrfs_io_bio *btrfs_failed_bio;
	struct btrfs_io_bio *btrfs_bio;

2367
	bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2368 2369 2370 2371
	if (!bio)
		return NULL;

	bio->bi_end_io = endio_func;
2372
	bio->bi_iter.bi_sector = failrec->logical >> 9;
2373
	bio->bi_bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
2374
	bio->bi_iter.bi_size = 0;
2375
	bio->bi_private = data;
2376

2377 2378 2379 2380 2381 2382 2383
	btrfs_failed_bio = btrfs_io_bio(failed_bio);
	if (btrfs_failed_bio->csum) {
		struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
		u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);

		btrfs_bio = btrfs_io_bio(bio);
		btrfs_bio->csum = btrfs_bio->csum_inline;
2384 2385
		icsum *= csum_size;
		memcpy(btrfs_bio->csum, btrfs_failed_bio->csum + icsum,
2386 2387 2388
		       csum_size);
	}

2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432
	bio_add_page(bio, page, failrec->len, pg_offset);

	return bio;
}

/*
 * this is a generic handler for readpage errors (default
 * readpage_io_failed_hook). if other copies exist, read those and write back
 * good data to the failed position. does not investigate in remapping the
 * failed extent elsewhere, hoping the device will be smart enough to do this as
 * needed
 */

static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
			      struct page *page, u64 start, u64 end,
			      int failed_mirror)
{
	struct io_failure_record *failrec;
	struct inode *inode = page->mapping->host;
	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
	struct bio *bio;
	int read_mode;
	int ret;

	BUG_ON(failed_bio->bi_rw & REQ_WRITE);

	ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
	if (ret)
		return ret;

	ret = btrfs_check_repairable(inode, failed_bio, failrec, failed_mirror);
	if (!ret) {
		free_io_failure(inode, failrec);
		return -EIO;
	}

	if (failed_bio->bi_vcnt > 1)
		read_mode = READ_SYNC | REQ_FAILFAST_DEV;
	else
		read_mode = READ_SYNC;

	phy_offset >>= inode->i_sb->s_blocksize_bits;
	bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
				      start - page_offset(page),
2433 2434
				      (int)phy_offset, failed_bio->bi_end_io,
				      NULL);
2435 2436 2437 2438
	if (!bio) {
		free_io_failure(inode, failrec);
		return -EIO;
	}
2439

2440 2441
	pr_debug("Repair Read Error: submitting new read[%#x] to this_mirror=%d, in_validation=%d\n",
		 read_mode, failrec->this_mirror, failrec->in_validation);
2442

2443 2444 2445
	ret = tree->ops->submit_bio_hook(inode, read_mode, bio,
					 failrec->this_mirror,
					 failrec->bio_flags, 0);
2446
	if (ret) {
2447
		free_io_failure(inode, failrec);
2448 2449 2450
		bio_put(bio);
	}

2451
	return ret;
2452 2453
}

2454 2455
/* lots and lots of room for performance fixes in the end_bio funcs */

2456 2457 2458 2459
int end_extent_writepage(struct page *page, int err, u64 start, u64 end)
{
	int uptodate = (err == 0);
	struct extent_io_tree *tree;
2460
	int ret = 0;
2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473

	tree = &BTRFS_I(page->mapping->host)->io_tree;

	if (tree->ops && tree->ops->writepage_end_io_hook) {
		ret = tree->ops->writepage_end_io_hook(page, start,
					       end, NULL, uptodate);
		if (ret)
			uptodate = 0;
	}

	if (!uptodate) {
		ClearPageUptodate(page);
		SetPageError(page);
2474 2475
		ret = ret < 0 ? ret : -EIO;
		mapping_set_error(page->mapping, ret);
2476 2477 2478 2479
	}
	return 0;
}

2480 2481 2482 2483 2484 2485 2486 2487 2488
/*
 * after a writepage IO is done, we need to:
 * clear the uptodate bits on error
 * clear the writeback bits in the extent tree for this IO
 * end_page_writeback if the page has no more pending IO
 *
 * Scheduling is not allowed, so the extent state tree is expected
 * to have one and only one object corresponding to this IO.
 */
2489
static void end_bio_extent_writepage(struct bio *bio)
2490
{
2491
	struct bio_vec *bvec;
2492 2493
	u64 start;
	u64 end;
2494
	int i;
2495

2496
	bio_for_each_segment_all(bvec, bio, i) {
2497
		struct page *page = bvec->bv_page;
2498

2499 2500 2501 2502 2503
		/* We always issue full-page reads, but if some block
		 * in a page fails to read, blk_update_request() will
		 * advance bv_offset and adjust bv_len to compensate.
		 * Print a warning for nonzero offsets, and an error
		 * if they don't add up to a full page.  */
2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514
		if (bvec->bv_offset || bvec->bv_len != PAGE_CACHE_SIZE) {
			if (bvec->bv_offset + bvec->bv_len != PAGE_CACHE_SIZE)
				btrfs_err(BTRFS_I(page->mapping->host)->root->fs_info,
				   "partial page write in btrfs with offset %u and length %u",
					bvec->bv_offset, bvec->bv_len);
			else
				btrfs_info(BTRFS_I(page->mapping->host)->root->fs_info,
				   "incomplete page write in btrfs with offset %u and "
				   "length %u",
					bvec->bv_offset, bvec->bv_len);
		}
2515

2516 2517
		start = page_offset(page);
		end = start + bvec->bv_offset + bvec->bv_len - 1;
2518

2519
		if (end_extent_writepage(page, bio->bi_error, start, end))
2520
			continue;
2521

2522
		end_page_writeback(page);
2523
	}
2524

2525 2526 2527
	bio_put(bio);
}

2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539
static void
endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64 len,
			      int uptodate)
{
	struct extent_state *cached = NULL;
	u64 end = start + len - 1;

	if (uptodate && tree->track_uptodate)
		set_extent_uptodate(tree, start, end, &cached, GFP_ATOMIC);
	unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
}

2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550
/*
 * after a readpage IO is done, we need to:
 * clear the uptodate bits on error
 * set the uptodate bits if things worked
 * set the page up to date if all extents in the tree are uptodate
 * clear the lock bit in the extent tree
 * unlock the page if there are no other extents locked for it
 *
 * Scheduling is not allowed, so the extent state tree is expected
 * to have one and only one object corresponding to this IO.
 */
2551
static void end_bio_extent_readpage(struct bio *bio)
2552
{
2553
	struct bio_vec *bvec;
2554
	int uptodate = !bio->bi_error;
2555
	struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
2556
	struct extent_io_tree *tree;
2557
	u64 offset = 0;
2558 2559
	u64 start;
	u64 end;
2560
	u64 len;
2561 2562
	u64 extent_start = 0;
	u64 extent_len = 0;
2563
	int mirror;
2564
	int ret;
2565
	int i;
2566

2567
	bio_for_each_segment_all(bvec, bio, i) {
2568
		struct page *page = bvec->bv_page;
2569
		struct inode *inode = page->mapping->host;
2570

2571
		pr_debug("end_bio_extent_readpage: bi_sector=%llu, err=%d, "
2572 2573
			 "mirror=%u\n", (u64)bio->bi_iter.bi_sector,
			 bio->bi_error, io_bio->mirror_num);
2574
		tree = &BTRFS_I(inode)->io_tree;
2575

2576 2577 2578 2579 2580
		/* We always issue full-page reads, but if some block
		 * in a page fails to read, blk_update_request() will
		 * advance bv_offset and adjust bv_len to compensate.
		 * Print a warning for nonzero offsets, and an error
		 * if they don't add up to a full page.  */
2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591
		if (bvec->bv_offset || bvec->bv_len != PAGE_CACHE_SIZE) {
			if (bvec->bv_offset + bvec->bv_len != PAGE_CACHE_SIZE)
				btrfs_err(BTRFS_I(page->mapping->host)->root->fs_info,
				   "partial page read in btrfs with offset %u and length %u",
					bvec->bv_offset, bvec->bv_len);
			else
				btrfs_info(BTRFS_I(page->mapping->host)->root->fs_info,
				   "incomplete page read in btrfs with offset %u and "
				   "length %u",
					bvec->bv_offset, bvec->bv_len);
		}
2592

2593 2594
		start = page_offset(page);
		end = start + bvec->bv_offset + bvec->bv_len - 1;
2595
		len = bvec->bv_len;
2596

2597
		mirror = io_bio->mirror_num;
2598 2599
		if (likely(uptodate && tree->ops &&
			   tree->ops->readpage_end_io_hook)) {
2600 2601 2602
			ret = tree->ops->readpage_end_io_hook(io_bio, offset,
							      page, start, end,
							      mirror);
2603
			if (ret)
2604
				uptodate = 0;
2605
			else
2606
				clean_io_failure(inode, start, page, 0);
2607
		}
2608

2609 2610 2611 2612
		if (likely(uptodate))
			goto readpage_ok;

		if (tree->ops && tree->ops->readpage_io_failed_hook) {
2613
			ret = tree->ops->readpage_io_failed_hook(page, mirror);
2614
			if (!ret && !bio->bi_error)
2615
				uptodate = 1;
2616
		} else {
2617 2618 2619 2620 2621 2622 2623 2624 2625 2626
			/*
			 * The generic bio_readpage_error handles errors the
			 * following way: If possible, new read requests are
			 * created and submitted and will end up in
			 * end_bio_extent_readpage as well (if we're lucky, not
			 * in the !uptodate case). In that case it returns 0 and
			 * we just go on with the next page in our bio. If it
			 * can't handle the error it will return -EIO and we
			 * remain responsible for that page.
			 */
2627 2628
			ret = bio_readpage_error(bio, offset, page, start, end,
						 mirror);
2629
			if (ret == 0) {
2630
				uptodate = !bio->bi_error;
2631
				offset += len;
2632 2633 2634
				continue;
			}
		}
2635
readpage_ok:
2636
		if (likely(uptodate)) {
2637 2638
			loff_t i_size = i_size_read(inode);
			pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
2639
			unsigned off;
2640 2641

			/* Zero out the end if this page straddles i_size */
2642 2643 2644
			off = i_size & (PAGE_CACHE_SIZE-1);
			if (page->index == end_index && off)
				zero_user_segment(page, off, PAGE_CACHE_SIZE);
2645
			SetPageUptodate(page);
2646
		} else {
2647 2648
			ClearPageUptodate(page);
			SetPageError(page);
2649
		}
2650
		unlock_page(page);
2651
		offset += len;
2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673

		if (unlikely(!uptodate)) {
			if (extent_len) {
				endio_readpage_release_extent(tree,
							      extent_start,
							      extent_len, 1);
				extent_start = 0;
				extent_len = 0;
			}
			endio_readpage_release_extent(tree, start,
						      end - start + 1, 0);
		} else if (!extent_len) {
			extent_start = start;
			extent_len = end + 1 - start;
		} else if (extent_start + extent_len == start) {
			extent_len += end + 1 - start;
		} else {
			endio_readpage_release_extent(tree, extent_start,
						      extent_len, uptodate);
			extent_start = start;
			extent_len = end + 1 - start;
		}
2674
	}
2675

2676 2677 2678
	if (extent_len)
		endio_readpage_release_extent(tree, extent_start, extent_len,
					      uptodate);
2679
	if (io_bio->end_io)
2680
		io_bio->end_io(io_bio, bio->bi_error);
2681 2682 2683
	bio_put(bio);
}

2684 2685 2686 2687
/*
 * this allocates from the btrfs_bioset.  We're returning a bio right now
 * but you can call btrfs_io_bio for the appropriate container_of magic
 */
2688 2689 2690
struct bio *
btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
		gfp_t gfp_flags)
2691
{
2692
	struct btrfs_io_bio *btrfs_bio;
2693 2694
	struct bio *bio;

2695
	bio = bio_alloc_bioset(gfp_flags, nr_vecs, btrfs_bioset);
2696 2697

	if (bio == NULL && (current->flags & PF_MEMALLOC)) {
2698 2699 2700 2701
		while (!bio && (nr_vecs /= 2)) {
			bio = bio_alloc_bioset(gfp_flags,
					       nr_vecs, btrfs_bioset);
		}
2702 2703 2704 2705
	}

	if (bio) {
		bio->bi_bdev = bdev;
2706
		bio->bi_iter.bi_sector = first_sector;
2707 2708 2709 2710
		btrfs_bio = btrfs_io_bio(bio);
		btrfs_bio->csum = NULL;
		btrfs_bio->csum_allocated = NULL;
		btrfs_bio->end_io = NULL;
2711 2712 2713 2714
	}
	return bio;
}

2715 2716
struct bio *btrfs_bio_clone(struct bio *bio, gfp_t gfp_mask)
{
2717 2718
	struct btrfs_io_bio *btrfs_bio;
	struct bio *new;
2719

2720 2721 2722 2723 2724 2725 2726 2727 2728
	new = bio_clone_bioset(bio, gfp_mask, btrfs_bioset);
	if (new) {
		btrfs_bio = btrfs_io_bio(new);
		btrfs_bio->csum = NULL;
		btrfs_bio->csum_allocated = NULL;
		btrfs_bio->end_io = NULL;
	}
	return new;
}
2729 2730 2731 2732

/* this also allocates from the btrfs_bioset */
struct bio *btrfs_io_bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
{
2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743
	struct btrfs_io_bio *btrfs_bio;
	struct bio *bio;

	bio = bio_alloc_bioset(gfp_mask, nr_iovecs, btrfs_bioset);
	if (bio) {
		btrfs_bio = btrfs_io_bio(bio);
		btrfs_bio->csum = NULL;
		btrfs_bio->csum_allocated = NULL;
		btrfs_bio->end_io = NULL;
	}
	return bio;
2744 2745 2746
}


2747 2748
static int __must_check submit_one_bio(int rw, struct bio *bio,
				       int mirror_num, unsigned long bio_flags)
2749 2750
{
	int ret = 0;
2751 2752 2753 2754 2755
	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
	struct page *page = bvec->bv_page;
	struct extent_io_tree *tree = bio->bi_private;
	u64 start;

M
Miao Xie 已提交
2756
	start = page_offset(page) + bvec->bv_offset;
2757

2758
	bio->bi_private = NULL;
2759 2760 2761

	bio_get(bio);

2762
	if (tree->ops && tree->ops->submit_bio_hook)
2763
		ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
2764
					   mirror_num, bio_flags, start);
2765
	else
2766
		btrfsic_submit_bio(rw, bio);
2767

2768 2769 2770 2771
	bio_put(bio);
	return ret;
}

2772
static int merge_bio(int rw, struct extent_io_tree *tree, struct page *page,
2773 2774 2775 2776 2777
		     unsigned long offset, size_t size, struct bio *bio,
		     unsigned long bio_flags)
{
	int ret = 0;
	if (tree->ops && tree->ops->merge_bio_hook)
2778
		ret = tree->ops->merge_bio_hook(rw, page, offset, size, bio,
2779 2780 2781 2782 2783 2784
						bio_flags);
	BUG_ON(ret < 0);
	return ret;

}

2785 2786 2787 2788 2789 2790
static int submit_extent_page(int rw, struct extent_io_tree *tree,
			      struct page *page, sector_t sector,
			      size_t size, unsigned long offset,
			      struct block_device *bdev,
			      struct bio **bio_ret,
			      unsigned long max_pages,
2791
			      bio_end_io_t end_io_func,
C
Chris Mason 已提交
2792 2793 2794
			      int mirror_num,
			      unsigned long prev_bio_flags,
			      unsigned long bio_flags)
2795 2796 2797 2798
{
	int ret = 0;
	struct bio *bio;
	int nr;
C
Chris Mason 已提交
2799 2800 2801
	int contig = 0;
	int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
	int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
2802
	size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
2803 2804 2805

	if (bio_ret && *bio_ret) {
		bio = *bio_ret;
C
Chris Mason 已提交
2806
		if (old_compressed)
2807
			contig = bio->bi_iter.bi_sector == sector;
C
Chris Mason 已提交
2808
		else
K
Kent Overstreet 已提交
2809
			contig = bio_end_sector(bio) == sector;
C
Chris Mason 已提交
2810 2811

		if (prev_bio_flags != bio_flags || !contig ||
2812
		    merge_bio(rw, tree, page, offset, page_size, bio, bio_flags) ||
C
Chris Mason 已提交
2813 2814 2815
		    bio_add_page(bio, page, page_size, offset) < page_size) {
			ret = submit_one_bio(rw, bio, mirror_num,
					     prev_bio_flags);
2816 2817
			if (ret < 0) {
				*bio_ret = NULL;
2818
				return ret;
2819
			}
2820 2821 2822 2823 2824
			bio = NULL;
		} else {
			return 0;
		}
	}
C
Chris Mason 已提交
2825 2826 2827 2828 2829
	if (this_compressed)
		nr = BIO_MAX_PAGES;
	else
		nr = bio_get_nr_vecs(bdev);

2830
	bio = btrfs_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
2831 2832
	if (!bio)
		return -ENOMEM;
2833

C
Chris Mason 已提交
2834
	bio_add_page(bio, page, page_size, offset);
2835 2836
	bio->bi_end_io = end_io_func;
	bio->bi_private = tree;
2837

C
Chris Mason 已提交
2838
	if (bio_ret)
2839
		*bio_ret = bio;
C
Chris Mason 已提交
2840
	else
C
Chris Mason 已提交
2841
		ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
2842 2843 2844 2845

	return ret;
}

2846 2847
static void attach_extent_buffer_page(struct extent_buffer *eb,
				      struct page *page)
2848 2849 2850 2851
{
	if (!PagePrivate(page)) {
		SetPagePrivate(page);
		page_cache_get(page);
J
Josef Bacik 已提交
2852 2853 2854
		set_page_private(page, (unsigned long)eb);
	} else {
		WARN_ON(page->private != (unsigned long)eb);
2855 2856 2857
	}
}

J
Josef Bacik 已提交
2858
void set_page_extent_mapped(struct page *page)
2859
{
J
Josef Bacik 已提交
2860 2861 2862 2863 2864
	if (!PagePrivate(page)) {
		SetPagePrivate(page);
		page_cache_get(page);
		set_page_private(page, EXTENT_PAGE_PRIVATE);
	}
2865 2866
}

2867 2868 2869 2870 2871 2872 2873 2874 2875
static struct extent_map *
__get_extent_map(struct inode *inode, struct page *page, size_t pg_offset,
		 u64 start, u64 len, get_extent_t *get_extent,
		 struct extent_map **em_cached)
{
	struct extent_map *em;

	if (em_cached && *em_cached) {
		em = *em_cached;
2876
		if (extent_map_in_tree(em) && start >= em->start &&
2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893
		    start < extent_map_end(em)) {
			atomic_inc(&em->refs);
			return em;
		}

		free_extent_map(em);
		*em_cached = NULL;
	}

	em = get_extent(inode, page, pg_offset, start, len, 0);
	if (em_cached && !IS_ERR_OR_NULL(em)) {
		BUG_ON(*em_cached);
		atomic_inc(&em->refs);
		*em_cached = em;
	}
	return em;
}
2894 2895 2896 2897
/*
 * basic readpage implementation.  Locked extent state structs are inserted
 * into the tree that are removed when the IO is done (by the end_io
 * handlers)
2898
 * XXX JDM: This needs looking at to ensure proper page locking
2899
 */
2900 2901 2902
static int __do_readpage(struct extent_io_tree *tree,
			 struct page *page,
			 get_extent_t *get_extent,
2903
			 struct extent_map **em_cached,
2904 2905
			 struct bio **bio, int mirror_num,
			 unsigned long *bio_flags, int rw)
2906 2907
{
	struct inode *inode = page->mapping->host;
M
Miao Xie 已提交
2908
	u64 start = page_offset(page);
2909 2910 2911 2912 2913 2914 2915 2916 2917 2918 2919 2920
	u64 page_end = start + PAGE_CACHE_SIZE - 1;
	u64 end;
	u64 cur = start;
	u64 extent_offset;
	u64 last_byte = i_size_read(inode);
	u64 block_start;
	u64 cur_end;
	sector_t sector;
	struct extent_map *em;
	struct block_device *bdev;
	int ret;
	int nr = 0;
2921
	int parent_locked = *bio_flags & EXTENT_BIO_PARENT_LOCKED;
2922
	size_t pg_offset = 0;
2923
	size_t iosize;
C
Chris Mason 已提交
2924
	size_t disk_io_size;
2925
	size_t blocksize = inode->i_sb->s_blocksize;
2926
	unsigned long this_bio_flag = *bio_flags & EXTENT_BIO_PARENT_LOCKED;
2927 2928 2929

	set_page_extent_mapped(page);

2930
	end = page_end;
D
Dan Magenheimer 已提交
2931 2932 2933
	if (!PageUptodate(page)) {
		if (cleancache_get_page(page) == 0) {
			BUG_ON(blocksize != PAGE_SIZE);
2934
			unlock_extent(tree, start, end);
D
Dan Magenheimer 已提交
2935 2936 2937 2938
			goto out;
		}
	}

C
Chris Mason 已提交
2939 2940 2941 2942 2943 2944
	if (page->index == last_byte >> PAGE_CACHE_SHIFT) {
		char *userpage;
		size_t zero_offset = last_byte & (PAGE_CACHE_SIZE - 1);

		if (zero_offset) {
			iosize = PAGE_CACHE_SIZE - zero_offset;
2945
			userpage = kmap_atomic(page);
C
Chris Mason 已提交
2946 2947
			memset(userpage + zero_offset, 0, iosize);
			flush_dcache_page(page);
2948
			kunmap_atomic(userpage);
C
Chris Mason 已提交
2949 2950
		}
	}
2951
	while (cur <= end) {
2952 2953
		unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;

2954 2955
		if (cur >= last_byte) {
			char *userpage;
2956 2957
			struct extent_state *cached = NULL;

2958
			iosize = PAGE_CACHE_SIZE - pg_offset;
2959
			userpage = kmap_atomic(page);
2960
			memset(userpage + pg_offset, 0, iosize);
2961
			flush_dcache_page(page);
2962
			kunmap_atomic(userpage);
2963
			set_extent_uptodate(tree, cur, cur + iosize - 1,
2964
					    &cached, GFP_NOFS);
2965 2966 2967 2968
			if (!parent_locked)
				unlock_extent_cached(tree, cur,
						     cur + iosize - 1,
						     &cached, GFP_NOFS);
2969 2970
			break;
		}
2971 2972
		em = __get_extent_map(inode, page, pg_offset, cur,
				      end - cur + 1, get_extent, em_cached);
2973
		if (IS_ERR_OR_NULL(em)) {
2974
			SetPageError(page);
2975 2976
			if (!parent_locked)
				unlock_extent(tree, cur, end);
2977 2978 2979 2980 2981 2982
			break;
		}
		extent_offset = cur - em->start;
		BUG_ON(extent_map_end(em) <= cur);
		BUG_ON(end < cur);

2983
		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2984
			this_bio_flag |= EXTENT_BIO_COMPRESSED;
2985 2986 2987
			extent_set_compress_type(&this_bio_flag,
						 em->compress_type);
		}
C
Chris Mason 已提交
2988

2989 2990
		iosize = min(extent_map_end(em) - cur, end - cur + 1);
		cur_end = min(extent_map_end(em) - 1, end);
2991
		iosize = ALIGN(iosize, blocksize);
C
Chris Mason 已提交
2992 2993 2994 2995 2996 2997 2998
		if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
			disk_io_size = em->block_len;
			sector = em->block_start >> 9;
		} else {
			sector = (em->block_start + extent_offset) >> 9;
			disk_io_size = iosize;
		}
2999 3000
		bdev = em->bdev;
		block_start = em->block_start;
Y
Yan Zheng 已提交
3001 3002
		if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
			block_start = EXTENT_MAP_HOLE;
3003 3004 3005 3006 3007 3008
		free_extent_map(em);
		em = NULL;

		/* we've found a hole, just zero and go on */
		if (block_start == EXTENT_MAP_HOLE) {
			char *userpage;
3009 3010
			struct extent_state *cached = NULL;

3011
			userpage = kmap_atomic(page);
3012
			memset(userpage + pg_offset, 0, iosize);
3013
			flush_dcache_page(page);
3014
			kunmap_atomic(userpage);
3015 3016

			set_extent_uptodate(tree, cur, cur + iosize - 1,
3017 3018 3019
					    &cached, GFP_NOFS);
			unlock_extent_cached(tree, cur, cur + iosize - 1,
			                     &cached, GFP_NOFS);
3020
			cur = cur + iosize;
3021
			pg_offset += iosize;
3022 3023 3024
			continue;
		}
		/* the get_extent function already copied into the page */
3025 3026
		if (test_range_bit(tree, cur, cur_end,
				   EXTENT_UPTODATE, 1, NULL)) {
3027
			check_page_uptodate(tree, page);
3028 3029
			if (!parent_locked)
				unlock_extent(tree, cur, cur + iosize - 1);
3030
			cur = cur + iosize;
3031
			pg_offset += iosize;
3032 3033
			continue;
		}
3034 3035 3036 3037 3038
		/* we have an inline extent but it didn't get marked up
		 * to date.  Error out
		 */
		if (block_start == EXTENT_MAP_INLINE) {
			SetPageError(page);
3039 3040
			if (!parent_locked)
				unlock_extent(tree, cur, cur + iosize - 1);
3041
			cur = cur + iosize;
3042
			pg_offset += iosize;
3043 3044
			continue;
		}
3045

3046
		pnr -= page->index;
3047
		ret = submit_extent_page(rw, tree, page,
3048
					 sector, disk_io_size, pg_offset,
3049
					 bdev, bio, pnr,
C
Chris Mason 已提交
3050 3051 3052
					 end_bio_extent_readpage, mirror_num,
					 *bio_flags,
					 this_bio_flag);
3053 3054 3055 3056
		if (!ret) {
			nr++;
			*bio_flags = this_bio_flag;
		} else {
3057
			SetPageError(page);
3058 3059
			if (!parent_locked)
				unlock_extent(tree, cur, cur + iosize - 1);
3060
		}
3061
		cur = cur + iosize;
3062
		pg_offset += iosize;
3063
	}
D
Dan Magenheimer 已提交
3064
out:
3065 3066 3067 3068 3069 3070 3071 3072
	if (!nr) {
		if (!PageError(page))
			SetPageUptodate(page);
		unlock_page(page);
	}
	return 0;
}

3073 3074 3075 3076
static inline void __do_contiguous_readpages(struct extent_io_tree *tree,
					     struct page *pages[], int nr_pages,
					     u64 start, u64 end,
					     get_extent_t *get_extent,
3077
					     struct extent_map **em_cached,
3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097
					     struct bio **bio, int mirror_num,
					     unsigned long *bio_flags, int rw)
{
	struct inode *inode;
	struct btrfs_ordered_extent *ordered;
	int index;

	inode = pages[0]->mapping->host;
	while (1) {
		lock_extent(tree, start, end);
		ordered = btrfs_lookup_ordered_range(inode, start,
						     end - start + 1);
		if (!ordered)
			break;
		unlock_extent(tree, start, end);
		btrfs_start_ordered_extent(inode, ordered, 1);
		btrfs_put_ordered_extent(ordered);
	}

	for (index = 0; index < nr_pages; index++) {
3098 3099
		__do_readpage(tree, pages[index], get_extent, em_cached, bio,
			      mirror_num, bio_flags, rw);
3100 3101 3102 3103 3104 3105 3106
		page_cache_release(pages[index]);
	}
}

static void __extent_readpages(struct extent_io_tree *tree,
			       struct page *pages[],
			       int nr_pages, get_extent_t *get_extent,
3107
			       struct extent_map **em_cached,
3108 3109 3110
			       struct bio **bio, int mirror_num,
			       unsigned long *bio_flags, int rw)
{
3111
	u64 start = 0;
3112 3113 3114
	u64 end = 0;
	u64 page_start;
	int index;
3115
	int first_index = 0;
3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127

	for (index = 0; index < nr_pages; index++) {
		page_start = page_offset(pages[index]);
		if (!end) {
			start = page_start;
			end = start + PAGE_CACHE_SIZE - 1;
			first_index = index;
		} else if (end + 1 == page_start) {
			end += PAGE_CACHE_SIZE;
		} else {
			__do_contiguous_readpages(tree, &pages[first_index],
						  index - first_index, start,
3128 3129 3130
						  end, get_extent, em_cached,
						  bio, mirror_num, bio_flags,
						  rw);
3131 3132 3133 3134 3135 3136 3137 3138 3139
			start = page_start;
			end = start + PAGE_CACHE_SIZE - 1;
			first_index = index;
		}
	}

	if (end)
		__do_contiguous_readpages(tree, &pages[first_index],
					  index - first_index, start,
3140
					  end, get_extent, em_cached, bio,
3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165
					  mirror_num, bio_flags, rw);
}

static int __extent_read_full_page(struct extent_io_tree *tree,
				   struct page *page,
				   get_extent_t *get_extent,
				   struct bio **bio, int mirror_num,
				   unsigned long *bio_flags, int rw)
{
	struct inode *inode = page->mapping->host;
	struct btrfs_ordered_extent *ordered;
	u64 start = page_offset(page);
	u64 end = start + PAGE_CACHE_SIZE - 1;
	int ret;

	while (1) {
		lock_extent(tree, start, end);
		ordered = btrfs_lookup_ordered_extent(inode, start);
		if (!ordered)
			break;
		unlock_extent(tree, start, end);
		btrfs_start_ordered_extent(inode, ordered, 1);
		btrfs_put_ordered_extent(ordered);
	}

3166 3167
	ret = __do_readpage(tree, page, get_extent, NULL, bio, mirror_num,
			    bio_flags, rw);
3168 3169 3170
	return ret;
}

3171
int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
3172
			    get_extent_t *get_extent, int mirror_num)
3173 3174
{
	struct bio *bio = NULL;
C
Chris Mason 已提交
3175
	unsigned long bio_flags = 0;
3176 3177
	int ret;

3178
	ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
3179
				      &bio_flags, READ);
3180
	if (bio)
3181
		ret = submit_one_bio(READ, bio, mirror_num, bio_flags);
3182 3183 3184
	return ret;
}

3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198
int extent_read_full_page_nolock(struct extent_io_tree *tree, struct page *page,
				 get_extent_t *get_extent, int mirror_num)
{
	struct bio *bio = NULL;
	unsigned long bio_flags = EXTENT_BIO_PARENT_LOCKED;
	int ret;

	ret = __do_readpage(tree, page, get_extent, NULL, &bio, mirror_num,
				      &bio_flags, READ);
	if (bio)
		ret = submit_one_bio(READ, bio, mirror_num, bio_flags);
	return ret;
}

3199 3200 3201 3202 3203 3204 3205 3206 3207 3208
static noinline void update_nr_written(struct page *page,
				      struct writeback_control *wbc,
				      unsigned long nr_written)
{
	wbc->nr_to_write -= nr_written;
	if (wbc->range_cyclic || (wbc->nr_to_write > 0 &&
	    wbc->range_start == 0 && wbc->range_end == LLONG_MAX))
		page->mapping->writeback_index = page->index + nr_written;
}

3209
/*
3210 3211 3212 3213 3214 3215 3216 3217
 * helper for __extent_writepage, doing all of the delayed allocation setup.
 *
 * This returns 1 if our fill_delalloc function did all the work required
 * to write the page (copy into inline extent).  In this case the IO has
 * been started and the page is already unlocked.
 *
 * This returns 0 if all went well (page still locked)
 * This returns < 0 if there were errors (page still locked)
3218
 */
3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240
static noinline_for_stack int writepage_delalloc(struct inode *inode,
			      struct page *page, struct writeback_control *wbc,
			      struct extent_page_data *epd,
			      u64 delalloc_start,
			      unsigned long *nr_written)
{
	struct extent_io_tree *tree = epd->tree;
	u64 page_end = delalloc_start + PAGE_CACHE_SIZE - 1;
	u64 nr_delalloc;
	u64 delalloc_to_write = 0;
	u64 delalloc_end = 0;
	int ret;
	int page_started = 0;

	if (epd->extent_locked || !tree->ops || !tree->ops->fill_delalloc)
		return 0;

	while (delalloc_end < page_end) {
		nr_delalloc = find_lock_delalloc_range(inode, tree,
					       page,
					       &delalloc_start,
					       &delalloc_end,
3241
					       BTRFS_MAX_EXTENT_SIZE);
3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291 3292 3293 3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314
		if (nr_delalloc == 0) {
			delalloc_start = delalloc_end + 1;
			continue;
		}
		ret = tree->ops->fill_delalloc(inode, page,
					       delalloc_start,
					       delalloc_end,
					       &page_started,
					       nr_written);
		/* File system has been set read-only */
		if (ret) {
			SetPageError(page);
			/* fill_delalloc should be return < 0 for error
			 * but just in case, we use > 0 here meaning the
			 * IO is started, so we don't want to return > 0
			 * unless things are going well.
			 */
			ret = ret < 0 ? ret : -EIO;
			goto done;
		}
		/*
		 * delalloc_end is already one less than the total
		 * length, so we don't subtract one from
		 * PAGE_CACHE_SIZE
		 */
		delalloc_to_write += (delalloc_end - delalloc_start +
				      PAGE_CACHE_SIZE) >>
				      PAGE_CACHE_SHIFT;
		delalloc_start = delalloc_end + 1;
	}
	if (wbc->nr_to_write < delalloc_to_write) {
		int thresh = 8192;

		if (delalloc_to_write < thresh * 2)
			thresh = delalloc_to_write;
		wbc->nr_to_write = min_t(u64, delalloc_to_write,
					 thresh);
	}

	/* did the fill delalloc function already unlock and start
	 * the IO?
	 */
	if (page_started) {
		/*
		 * we've unlocked the page, so we can't update
		 * the mapping's writeback index, just update
		 * nr_to_write.
		 */
		wbc->nr_to_write -= *nr_written;
		return 1;
	}

	ret = 0;

done:
	return ret;
}

/*
 * helper for __extent_writepage.  This calls the writepage start hooks,
 * and does the loop to map the page into extents and bios.
 *
 * We return 1 if the IO is started and the page is unlocked,
 * 0 if all went well (page still locked)
 * < 0 if there were errors (page still locked)
 */
static noinline_for_stack int __extent_writepage_io(struct inode *inode,
				 struct page *page,
				 struct writeback_control *wbc,
				 struct extent_page_data *epd,
				 loff_t i_size,
				 unsigned long nr_written,
				 int write_flags, int *nr_ret)
3315 3316
{
	struct extent_io_tree *tree = epd->tree;
M
Miao Xie 已提交
3317
	u64 start = page_offset(page);
3318 3319 3320 3321 3322 3323 3324
	u64 page_end = start + PAGE_CACHE_SIZE - 1;
	u64 end;
	u64 cur = start;
	u64 extent_offset;
	u64 block_start;
	u64 iosize;
	sector_t sector;
3325
	struct extent_state *cached_state = NULL;
3326 3327
	struct extent_map *em;
	struct block_device *bdev;
3328
	size_t pg_offset = 0;
3329
	size_t blocksize;
3330 3331 3332
	int ret = 0;
	int nr = 0;
	bool compressed;
C
Chris Mason 已提交
3333

3334
	if (tree->ops && tree->ops->writepage_start_hook) {
C
Chris Mason 已提交
3335 3336
		ret = tree->ops->writepage_start_hook(page, start,
						      page_end);
3337 3338 3339 3340 3341 3342
		if (ret) {
			/* Fixup worker will requeue */
			if (ret == -EBUSY)
				wbc->pages_skipped++;
			else
				redirty_page_for_writepage(wbc, page);
3343

3344
			update_nr_written(page, wbc, nr_written);
3345
			unlock_page(page);
3346
			ret = 1;
3347
			goto done_unlocked;
3348 3349 3350
		}
	}

3351 3352 3353 3354 3355
	/*
	 * we don't want to touch the inode after unlocking the page,
	 * so we update the mapping writeback index now
	 */
	update_nr_written(page, wbc, nr_written + 1);
3356

3357
	end = page_end;
3358
	if (i_size <= start) {
3359 3360 3361
		if (tree->ops && tree->ops->writepage_end_io_hook)
			tree->ops->writepage_end_io_hook(page, start,
							 page_end, NULL, 1);
3362 3363 3364 3365 3366 3367
		goto done;
	}

	blocksize = inode->i_sb->s_blocksize;

	while (cur <= end) {
3368 3369
		u64 em_end;
		if (cur >= i_size) {
3370 3371 3372
			if (tree->ops && tree->ops->writepage_end_io_hook)
				tree->ops->writepage_end_io_hook(page, cur,
							 page_end, NULL, 1);
3373 3374
			break;
		}
3375
		em = epd->get_extent(inode, page, pg_offset, cur,
3376
				     end - cur + 1, 1);
3377
		if (IS_ERR_OR_NULL(em)) {
3378
			SetPageError(page);
3379
			ret = PTR_ERR_OR_ZERO(em);
3380 3381 3382 3383
			break;
		}

		extent_offset = cur - em->start;
3384 3385
		em_end = extent_map_end(em);
		BUG_ON(em_end <= cur);
3386
		BUG_ON(end < cur);
3387
		iosize = min(em_end - cur, end - cur + 1);
3388
		iosize = ALIGN(iosize, blocksize);
3389 3390 3391
		sector = (em->block_start + extent_offset) >> 9;
		bdev = em->bdev;
		block_start = em->block_start;
C
Chris Mason 已提交
3392
		compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
3393 3394 3395
		free_extent_map(em);
		em = NULL;

C
Chris Mason 已提交
3396 3397 3398 3399 3400
		/*
		 * compressed and inline extents are written through other
		 * paths in the FS
		 */
		if (compressed || block_start == EXTENT_MAP_HOLE ||
3401
		    block_start == EXTENT_MAP_INLINE) {
C
Chris Mason 已提交
3402 3403 3404 3405 3406 3407
			/*
			 * end_io notification does not happen here for
			 * compressed extents
			 */
			if (!compressed && tree->ops &&
			    tree->ops->writepage_end_io_hook)
3408 3409 3410
				tree->ops->writepage_end_io_hook(page, cur,
							 cur + iosize - 1,
							 NULL, 1);
C
Chris Mason 已提交
3411 3412 3413 3414 3415 3416 3417 3418 3419
			else if (compressed) {
				/* we don't want to end_page_writeback on
				 * a compressed extent.  this happens
				 * elsewhere
				 */
				nr++;
			}

			cur += iosize;
3420
			pg_offset += iosize;
3421 3422
			continue;
		}
C
Chris Mason 已提交
3423

3424 3425 3426 3427 3428 3429
		if (tree->ops && tree->ops->writepage_io_hook) {
			ret = tree->ops->writepage_io_hook(page, cur,
						cur + iosize - 1);
		} else {
			ret = 0;
		}
3430
		if (ret) {
3431
			SetPageError(page);
3432
		} else {
3433
			unsigned long max_nr = (i_size >> PAGE_CACHE_SHIFT) + 1;
3434

3435 3436
			set_range_writeback(tree, cur, cur + iosize - 1);
			if (!PageWriteback(page)) {
3437 3438
				btrfs_err(BTRFS_I(inode)->root->fs_info,
					   "page %lu not writeback, cur %llu end %llu",
3439
				       page->index, cur, end);
3440 3441
			}

3442 3443 3444
			ret = submit_extent_page(write_flags, tree, page,
						 sector, iosize, pg_offset,
						 bdev, &epd->bio, max_nr,
C
Chris Mason 已提交
3445 3446
						 end_bio_extent_writepage,
						 0, 0, 0);
3447 3448 3449 3450
			if (ret)
				SetPageError(page);
		}
		cur = cur + iosize;
3451
		pg_offset += iosize;
3452 3453
		nr++;
	}
3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527 3528
done:
	*nr_ret = nr;

done_unlocked:

	/* drop our reference on any cached states */
	free_extent_state(cached_state);
	return ret;
}

/*
 * the writepage semantics are similar to regular writepage.  extent
 * records are inserted to lock ranges in the tree, and as dirty areas
 * are found, they are marked writeback.  Then the lock bits are removed
 * and the end_io handler clears the writeback ranges
 */
static int __extent_writepage(struct page *page, struct writeback_control *wbc,
			      void *data)
{
	struct inode *inode = page->mapping->host;
	struct extent_page_data *epd = data;
	u64 start = page_offset(page);
	u64 page_end = start + PAGE_CACHE_SIZE - 1;
	int ret;
	int nr = 0;
	size_t pg_offset = 0;
	loff_t i_size = i_size_read(inode);
	unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
	int write_flags;
	unsigned long nr_written = 0;

	if (wbc->sync_mode == WB_SYNC_ALL)
		write_flags = WRITE_SYNC;
	else
		write_flags = WRITE;

	trace___extent_writepage(page, inode, wbc);

	WARN_ON(!PageLocked(page));

	ClearPageError(page);

	pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
	if (page->index > end_index ||
	   (page->index == end_index && !pg_offset)) {
		page->mapping->a_ops->invalidatepage(page, 0, PAGE_CACHE_SIZE);
		unlock_page(page);
		return 0;
	}

	if (page->index == end_index) {
		char *userpage;

		userpage = kmap_atomic(page);
		memset(userpage + pg_offset, 0,
		       PAGE_CACHE_SIZE - pg_offset);
		kunmap_atomic(userpage);
		flush_dcache_page(page);
	}

	pg_offset = 0;

	set_page_extent_mapped(page);

	ret = writepage_delalloc(inode, page, wbc, epd, start, &nr_written);
	if (ret == 1)
		goto done_unlocked;
	if (ret)
		goto done;

	ret = __extent_writepage_io(inode, page, wbc, epd,
				    i_size, nr_written, write_flags, &nr);
	if (ret == 1)
		goto done_unlocked;

3529 3530 3531 3532 3533 3534
done:
	if (nr == 0) {
		/* make sure the mapping tag for page dirty gets cleared */
		set_page_writeback(page);
		end_page_writeback(page);
	}
3535 3536 3537 3538
	if (PageError(page)) {
		ret = ret < 0 ? ret : -EIO;
		end_extent_writepage(page, ret, start, page_end);
	}
3539
	unlock_page(page);
3540
	return ret;
3541

3542
done_unlocked:
3543 3544 3545
	return 0;
}

3546
void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
3547
{
3548 3549
	wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
		       TASK_UNINTERRUPTIBLE);
3550 3551
}

3552 3553 3554 3555
static noinline_for_stack int
lock_extent_buffer_for_io(struct extent_buffer *eb,
			  struct btrfs_fs_info *fs_info,
			  struct extent_page_data *epd)
3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574
{
	unsigned long i, num_pages;
	int flush = 0;
	int ret = 0;

	if (!btrfs_try_tree_write_lock(eb)) {
		flush = 1;
		flush_write_bio(epd);
		btrfs_tree_lock(eb);
	}

	if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
		btrfs_tree_unlock(eb);
		if (!epd->sync_io)
			return 0;
		if (!flush) {
			flush_write_bio(epd);
			flush = 1;
		}
C
Chris Mason 已提交
3575 3576 3577 3578 3579
		while (1) {
			wait_on_extent_buffer_writeback(eb);
			btrfs_tree_lock(eb);
			if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
				break;
3580 3581 3582 3583
			btrfs_tree_unlock(eb);
		}
	}

3584 3585 3586 3587 3588 3589
	/*
	 * We need to do this to prevent races in people who check if the eb is
	 * under IO since we can end up having no IO bits set for a short period
	 * of time.
	 */
	spin_lock(&eb->refs_lock);
3590 3591
	if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
		set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3592
		spin_unlock(&eb->refs_lock);
3593
		btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3594 3595 3596
		__percpu_counter_add(&fs_info->dirty_metadata_bytes,
				     -eb->len,
				     fs_info->dirty_metadata_batch);
3597
		ret = 1;
3598 3599
	} else {
		spin_unlock(&eb->refs_lock);
3600 3601 3602 3603 3604 3605 3606 3607 3608
	}

	btrfs_tree_unlock(eb);

	if (!ret)
		return ret;

	num_pages = num_extent_pages(eb->start, eb->len);
	for (i = 0; i < num_pages; i++) {
3609
		struct page *p = eb->pages[i];
3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 3624 3625

		if (!trylock_page(p)) {
			if (!flush) {
				flush_write_bio(epd);
				flush = 1;
			}
			lock_page(p);
		}
	}

	return ret;
}

static void end_extent_buffer_writeback(struct extent_buffer *eb)
{
	clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3626
	smp_mb__after_atomic();
3627 3628 3629
	wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
}

3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651 3652 3653 3654 3655 3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691
static void set_btree_ioerr(struct page *page)
{
	struct extent_buffer *eb = (struct extent_buffer *)page->private;
	struct btrfs_inode *btree_ino = BTRFS_I(eb->fs_info->btree_inode);

	SetPageError(page);
	if (test_and_set_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags))
		return;

	/*
	 * If writeback for a btree extent that doesn't belong to a log tree
	 * failed, increment the counter transaction->eb_write_errors.
	 * We do this because while the transaction is running and before it's
	 * committing (when we call filemap_fdata[write|wait]_range against
	 * the btree inode), we might have
	 * btree_inode->i_mapping->a_ops->writepages() called by the VM - if it
	 * returns an error or an error happens during writeback, when we're
	 * committing the transaction we wouldn't know about it, since the pages
	 * can be no longer dirty nor marked anymore for writeback (if a
	 * subsequent modification to the extent buffer didn't happen before the
	 * transaction commit), which makes filemap_fdata[write|wait]_range not
	 * able to find the pages tagged with SetPageError at transaction
	 * commit time. So if this happens we must abort the transaction,
	 * otherwise we commit a super block with btree roots that point to
	 * btree nodes/leafs whose content on disk is invalid - either garbage
	 * or the content of some node/leaf from a past generation that got
	 * cowed or deleted and is no longer valid.
	 *
	 * Note: setting AS_EIO/AS_ENOSPC in the btree inode's i_mapping would
	 * not be enough - we need to distinguish between log tree extents vs
	 * non-log tree extents, and the next filemap_fdatawait_range() call
	 * will catch and clear such errors in the mapping - and that call might
	 * be from a log sync and not from a transaction commit. Also, checking
	 * for the eb flag EXTENT_BUFFER_WRITE_ERR at transaction commit time is
	 * not done and would not be reliable - the eb might have been released
	 * from memory and reading it back again means that flag would not be
	 * set (since it's a runtime flag, not persisted on disk).
	 *
	 * Using the flags below in the btree inode also makes us achieve the
	 * goal of AS_EIO/AS_ENOSPC when writepages() returns success, started
	 * writeback for all dirty pages and before filemap_fdatawait_range()
	 * is called, the writeback for all dirty pages had already finished
	 * with errors - because we were not using AS_EIO/AS_ENOSPC,
	 * filemap_fdatawait_range() would return success, as it could not know
	 * that writeback errors happened (the pages were no longer tagged for
	 * writeback).
	 */
	switch (eb->log_index) {
	case -1:
		set_bit(BTRFS_INODE_BTREE_ERR, &btree_ino->runtime_flags);
		break;
	case 0:
		set_bit(BTRFS_INODE_BTREE_LOG1_ERR, &btree_ino->runtime_flags);
		break;
	case 1:
		set_bit(BTRFS_INODE_BTREE_LOG2_ERR, &btree_ino->runtime_flags);
		break;
	default:
		BUG(); /* unexpected, logic error */
	}
}

3692
static void end_bio_extent_buffer_writepage(struct bio *bio)
3693
{
3694
	struct bio_vec *bvec;
3695
	struct extent_buffer *eb;
3696
	int i, done;
3697

3698
	bio_for_each_segment_all(bvec, bio, i) {
3699 3700 3701 3702 3703 3704
		struct page *page = bvec->bv_page;

		eb = (struct extent_buffer *)page->private;
		BUG_ON(!eb);
		done = atomic_dec_and_test(&eb->io_pages);

3705 3706
		if (bio->bi_error ||
		    test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) {
3707
			ClearPageUptodate(page);
3708
			set_btree_ioerr(page);
3709 3710 3711 3712 3713 3714 3715 3716
		}

		end_page_writeback(page);

		if (!done)
			continue;

		end_extent_buffer_writeback(eb);
3717
	}
3718 3719 3720 3721

	bio_put(bio);
}

3722
static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
3723 3724 3725 3726 3727
			struct btrfs_fs_info *fs_info,
			struct writeback_control *wbc,
			struct extent_page_data *epd)
{
	struct block_device *bdev = fs_info->fs_devices->latest_bdev;
3728
	struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
3729 3730
	u64 offset = eb->start;
	unsigned long i, num_pages;
3731
	unsigned long bio_flags = 0;
3732
	int rw = (epd->sync_io ? WRITE_SYNC : WRITE) | REQ_META;
3733
	int ret = 0;
3734

3735
	clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
3736 3737
	num_pages = num_extent_pages(eb->start, eb->len);
	atomic_set(&eb->io_pages, num_pages);
3738 3739 3740
	if (btrfs_header_owner(eb) == BTRFS_TREE_LOG_OBJECTID)
		bio_flags = EXTENT_BIO_TREE_LOG;

3741
	for (i = 0; i < num_pages; i++) {
3742
		struct page *p = eb->pages[i];
3743 3744 3745

		clear_page_dirty_for_io(p);
		set_page_writeback(p);
3746
		ret = submit_extent_page(rw, tree, p, offset >> 9,
3747 3748
					 PAGE_CACHE_SIZE, 0, bdev, &epd->bio,
					 -1, end_bio_extent_buffer_writepage,
3749 3750
					 0, epd->bio_flags, bio_flags);
		epd->bio_flags = bio_flags;
3751
		if (ret) {
3752
			set_btree_ioerr(p);
3753
			end_page_writeback(p);
3754 3755 3756 3757 3758 3759 3760 3761 3762 3763 3764 3765
			if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
				end_extent_buffer_writeback(eb);
			ret = -EIO;
			break;
		}
		offset += PAGE_CACHE_SIZE;
		update_nr_written(p, wbc, 1);
		unlock_page(p);
	}

	if (unlikely(ret)) {
		for (; i < num_pages; i++) {
3766
			struct page *p = eb->pages[i];
3767
			clear_page_dirty_for_io(p);
3768 3769 3770 3771 3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785
			unlock_page(p);
		}
	}

	return ret;
}

int btree_write_cache_pages(struct address_space *mapping,
				   struct writeback_control *wbc)
{
	struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
	struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info;
	struct extent_buffer *eb, *prev_eb = NULL;
	struct extent_page_data epd = {
		.bio = NULL,
		.tree = tree,
		.extent_locked = 0,
		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
3786
		.bio_flags = 0,
3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803 3804 3805 3806 3807 3808 3809 3810 3811 3812 3813 3814 3815 3816 3817 3818 3819 3820 3821 3822 3823 3824 3825 3826 3827 3828 3829 3830
	};
	int ret = 0;
	int done = 0;
	int nr_to_write_done = 0;
	struct pagevec pvec;
	int nr_pages;
	pgoff_t index;
	pgoff_t end;		/* Inclusive */
	int scanned = 0;
	int tag;

	pagevec_init(&pvec, 0);
	if (wbc->range_cyclic) {
		index = mapping->writeback_index; /* Start from prev offset */
		end = -1;
	} else {
		index = wbc->range_start >> PAGE_CACHE_SHIFT;
		end = wbc->range_end >> PAGE_CACHE_SHIFT;
		scanned = 1;
	}
	if (wbc->sync_mode == WB_SYNC_ALL)
		tag = PAGECACHE_TAG_TOWRITE;
	else
		tag = PAGECACHE_TAG_DIRTY;
retry:
	if (wbc->sync_mode == WB_SYNC_ALL)
		tag_pages_for_writeback(mapping, index, end);
	while (!done && !nr_to_write_done && (index <= end) &&
	       (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
			min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
		unsigned i;

		scanned = 1;
		for (i = 0; i < nr_pages; i++) {
			struct page *page = pvec.pages[i];

			if (!PagePrivate(page))
				continue;

			if (!wbc->range_cyclic && page->index > end) {
				done = 1;
				break;
			}

3831 3832 3833 3834 3835 3836
			spin_lock(&mapping->private_lock);
			if (!PagePrivate(page)) {
				spin_unlock(&mapping->private_lock);
				continue;
			}

3837
			eb = (struct extent_buffer *)page->private;
3838 3839 3840 3841 3842 3843

			/*
			 * Shouldn't happen and normally this would be a BUG_ON
			 * but no sense in crashing the users box for something
			 * we can survive anyway.
			 */
3844
			if (WARN_ON(!eb)) {
3845
				spin_unlock(&mapping->private_lock);
3846 3847 3848
				continue;
			}

3849 3850
			if (eb == prev_eb) {
				spin_unlock(&mapping->private_lock);
3851
				continue;
3852
			}
3853

3854 3855 3856
			ret = atomic_inc_not_zero(&eb->refs);
			spin_unlock(&mapping->private_lock);
			if (!ret)
3857 3858 3859 3860 3861 3862 3863 3864 3865 3866 3867 3868 3869 3870 3871 3872 3873 3874 3875 3876 3877 3878 3879 3880 3881 3882 3883 3884 3885 3886 3887 3888 3889 3890 3891 3892 3893 3894 3895 3896
				continue;

			prev_eb = eb;
			ret = lock_extent_buffer_for_io(eb, fs_info, &epd);
			if (!ret) {
				free_extent_buffer(eb);
				continue;
			}

			ret = write_one_eb(eb, fs_info, wbc, &epd);
			if (ret) {
				done = 1;
				free_extent_buffer(eb);
				break;
			}
			free_extent_buffer(eb);

			/*
			 * the filesystem may choose to bump up nr_to_write.
			 * We have to make sure to honor the new nr_to_write
			 * at any time
			 */
			nr_to_write_done = wbc->nr_to_write <= 0;
		}
		pagevec_release(&pvec);
		cond_resched();
	}
	if (!scanned && !done) {
		/*
		 * We hit the last page and there is more work to be done: wrap
		 * back to the start of the file
		 */
		scanned = 1;
		index = 0;
		goto retry;
	}
	flush_write_bio(&epd);
	return ret;
}

3897
/**
C
Chris Mason 已提交
3898
 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
3899 3900 3901 3902 3903 3904 3905 3906 3907 3908 3909 3910 3911
 * @mapping: address space structure to write
 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
 * @writepage: function called for each page
 * @data: data passed to writepage function
 *
 * If a page is already under I/O, write_cache_pages() skips it, even
 * if it's dirty.  This is desirable behaviour for memory-cleaning writeback,
 * but it is INCORRECT for data-integrity system calls such as fsync().  fsync()
 * and msync() need to guarantee that all the data which was dirty at the time
 * the call was made get new I/O started against them.  If wbc->sync_mode is
 * WB_SYNC_ALL then we were called for data integrity and we must wait for
 * existing IO to complete.
 */
3912
static int extent_write_cache_pages(struct extent_io_tree *tree,
C
Chris Mason 已提交
3913 3914
			     struct address_space *mapping,
			     struct writeback_control *wbc,
C
Chris Mason 已提交
3915 3916
			     writepage_t writepage, void *data,
			     void (*flush_fn)(void *))
3917
{
3918
	struct inode *inode = mapping->host;
3919 3920
	int ret = 0;
	int done = 0;
3921
	int err = 0;
3922
	int nr_to_write_done = 0;
3923 3924 3925 3926 3927
	struct pagevec pvec;
	int nr_pages;
	pgoff_t index;
	pgoff_t end;		/* Inclusive */
	int scanned = 0;
3928
	int tag;
3929

3930 3931 3932 3933 3934 3935 3936 3937 3938 3939 3940 3941
	/*
	 * We have to hold onto the inode so that ordered extents can do their
	 * work when the IO finishes.  The alternative to this is failing to add
	 * an ordered extent if the igrab() fails there and that is a huge pain
	 * to deal with, so instead just hold onto the inode throughout the
	 * writepages operation.  If it fails here we are freeing up the inode
	 * anyway and we'd rather not waste our time writing out stuff that is
	 * going to be truncated anyway.
	 */
	if (!igrab(inode))
		return 0;

3942 3943 3944 3945 3946 3947 3948 3949 3950
	pagevec_init(&pvec, 0);
	if (wbc->range_cyclic) {
		index = mapping->writeback_index; /* Start from prev offset */
		end = -1;
	} else {
		index = wbc->range_start >> PAGE_CACHE_SHIFT;
		end = wbc->range_end >> PAGE_CACHE_SHIFT;
		scanned = 1;
	}
3951 3952 3953 3954
	if (wbc->sync_mode == WB_SYNC_ALL)
		tag = PAGECACHE_TAG_TOWRITE;
	else
		tag = PAGECACHE_TAG_DIRTY;
3955
retry:
3956 3957
	if (wbc->sync_mode == WB_SYNC_ALL)
		tag_pages_for_writeback(mapping, index, end);
3958
	while (!done && !nr_to_write_done && (index <= end) &&
3959 3960
	       (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
			min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
3961 3962 3963 3964 3965 3966 3967 3968 3969 3970 3971 3972 3973
		unsigned i;

		scanned = 1;
		for (i = 0; i < nr_pages; i++) {
			struct page *page = pvec.pages[i];

			/*
			 * At this point we hold neither mapping->tree_lock nor
			 * lock on the page itself: the page may be truncated or
			 * invalidated (changing page->mapping to NULL), or even
			 * swizzled back from swapper_space to tmpfs file
			 * mapping
			 */
3974 3975 3976
			if (!trylock_page(page)) {
				flush_fn(data);
				lock_page(page);
3977
			}
3978 3979 3980 3981 3982 3983 3984 3985 3986 3987 3988 3989

			if (unlikely(page->mapping != mapping)) {
				unlock_page(page);
				continue;
			}

			if (!wbc->range_cyclic && page->index > end) {
				done = 1;
				unlock_page(page);
				continue;
			}

C
Chris Mason 已提交
3990
			if (wbc->sync_mode != WB_SYNC_NONE) {
3991 3992
				if (PageWriteback(page))
					flush_fn(data);
3993
				wait_on_page_writeback(page);
C
Chris Mason 已提交
3994
			}
3995 3996 3997 3998 3999 4000 4001 4002 4003 4004 4005 4006 4007

			if (PageWriteback(page) ||
			    !clear_page_dirty_for_io(page)) {
				unlock_page(page);
				continue;
			}

			ret = (*writepage)(page, wbc, data);

			if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
				unlock_page(page);
				ret = 0;
			}
4008 4009
			if (!err && ret < 0)
				err = ret;
4010 4011 4012 4013 4014 4015 4016

			/*
			 * the filesystem may choose to bump up nr_to_write.
			 * We have to make sure to honor the new nr_to_write
			 * at any time
			 */
			nr_to_write_done = wbc->nr_to_write <= 0;
4017 4018 4019 4020
		}
		pagevec_release(&pvec);
		cond_resched();
	}
4021
	if (!scanned && !done && !err) {
4022 4023 4024 4025 4026 4027 4028 4029
		/*
		 * We hit the last page and there is more work to be done: wrap
		 * back to the start of the file
		 */
		scanned = 1;
		index = 0;
		goto retry;
	}
4030
	btrfs_add_delayed_iput(inode);
4031
	return err;
4032 4033
}

4034
static void flush_epd_write_bio(struct extent_page_data *epd)
C
Chris Mason 已提交
4035 4036
{
	if (epd->bio) {
4037 4038 4039
		int rw = WRITE;
		int ret;

4040
		if (epd->sync_io)
4041 4042
			rw = WRITE_SYNC;

4043
		ret = submit_one_bio(rw, epd->bio, 0, epd->bio_flags);
4044
		BUG_ON(ret < 0); /* -ENOMEM */
C
Chris Mason 已提交
4045 4046 4047 4048
		epd->bio = NULL;
	}
}

4049 4050 4051 4052 4053 4054
static noinline void flush_write_bio(void *data)
{
	struct extent_page_data *epd = data;
	flush_epd_write_bio(epd);
}

4055 4056 4057 4058 4059 4060 4061 4062 4063
int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
			  get_extent_t *get_extent,
			  struct writeback_control *wbc)
{
	int ret;
	struct extent_page_data epd = {
		.bio = NULL,
		.tree = tree,
		.get_extent = get_extent,
4064
		.extent_locked = 0,
4065
		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
4066
		.bio_flags = 0,
4067 4068 4069 4070
	};

	ret = __extent_writepage(page, wbc, &epd);

4071
	flush_epd_write_bio(&epd);
4072 4073 4074
	return ret;
}

4075 4076 4077 4078 4079 4080 4081 4082 4083 4084 4085 4086 4087 4088 4089
int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
			      u64 start, u64 end, get_extent_t *get_extent,
			      int mode)
{
	int ret = 0;
	struct address_space *mapping = inode->i_mapping;
	struct page *page;
	unsigned long nr_pages = (end - start + PAGE_CACHE_SIZE) >>
		PAGE_CACHE_SHIFT;

	struct extent_page_data epd = {
		.bio = NULL,
		.tree = tree,
		.get_extent = get_extent,
		.extent_locked = 1,
4090
		.sync_io = mode == WB_SYNC_ALL,
4091
		.bio_flags = 0,
4092 4093 4094 4095 4096 4097 4098 4099
	};
	struct writeback_control wbc_writepages = {
		.sync_mode	= mode,
		.nr_to_write	= nr_pages * 2,
		.range_start	= start,
		.range_end	= end + 1,
	};

C
Chris Mason 已提交
4100
	while (start <= end) {
4101 4102 4103 4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114
		page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
		if (clear_page_dirty_for_io(page))
			ret = __extent_writepage(page, &wbc_writepages, &epd);
		else {
			if (tree->ops && tree->ops->writepage_end_io_hook)
				tree->ops->writepage_end_io_hook(page, start,
						 start + PAGE_CACHE_SIZE - 1,
						 NULL, 1);
			unlock_page(page);
		}
		page_cache_release(page);
		start += PAGE_CACHE_SIZE;
	}

4115
	flush_epd_write_bio(&epd);
4116 4117
	return ret;
}
4118 4119 4120 4121 4122 4123 4124 4125 4126 4127 4128

int extent_writepages(struct extent_io_tree *tree,
		      struct address_space *mapping,
		      get_extent_t *get_extent,
		      struct writeback_control *wbc)
{
	int ret = 0;
	struct extent_page_data epd = {
		.bio = NULL,
		.tree = tree,
		.get_extent = get_extent,
4129
		.extent_locked = 0,
4130
		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
4131
		.bio_flags = 0,
4132 4133
	};

C
Chris Mason 已提交
4134
	ret = extent_write_cache_pages(tree, mapping, wbc,
C
Chris Mason 已提交
4135 4136
				       __extent_writepage, &epd,
				       flush_write_bio);
4137
	flush_epd_write_bio(&epd);
4138 4139 4140 4141 4142 4143 4144 4145 4146 4147
	return ret;
}

int extent_readpages(struct extent_io_tree *tree,
		     struct address_space *mapping,
		     struct list_head *pages, unsigned nr_pages,
		     get_extent_t get_extent)
{
	struct bio *bio = NULL;
	unsigned page_idx;
C
Chris Mason 已提交
4148
	unsigned long bio_flags = 0;
L
Liu Bo 已提交
4149 4150
	struct page *pagepool[16];
	struct page *page;
4151
	struct extent_map *em_cached = NULL;
L
Liu Bo 已提交
4152
	int nr = 0;
4153 4154

	for (page_idx = 0; page_idx < nr_pages; page_idx++) {
L
Liu Bo 已提交
4155
		page = list_entry(pages->prev, struct page, lru);
4156 4157 4158

		prefetchw(&page->flags);
		list_del(&page->lru);
L
Liu Bo 已提交
4159
		if (add_to_page_cache_lru(page, mapping,
4160
					page->index, GFP_NOFS)) {
L
Liu Bo 已提交
4161 4162
			page_cache_release(page);
			continue;
4163
		}
L
Liu Bo 已提交
4164 4165 4166 4167

		pagepool[nr++] = page;
		if (nr < ARRAY_SIZE(pagepool))
			continue;
4168
		__extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
4169
				   &bio, 0, &bio_flags, READ);
L
Liu Bo 已提交
4170
		nr = 0;
4171
	}
4172
	if (nr)
4173
		__extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
4174
				   &bio, 0, &bio_flags, READ);
L
Liu Bo 已提交
4175

4176 4177 4178
	if (em_cached)
		free_extent_map(em_cached);

4179 4180
	BUG_ON(!list_empty(pages));
	if (bio)
4181
		return submit_one_bio(READ, bio, 0, bio_flags);
4182 4183 4184 4185 4186 4187 4188 4189 4190 4191 4192
	return 0;
}

/*
 * basic invalidatepage code, this waits on any locked or writeback
 * ranges corresponding to the page, and then deletes any extent state
 * records from the tree
 */
int extent_invalidatepage(struct extent_io_tree *tree,
			  struct page *page, unsigned long offset)
{
4193
	struct extent_state *cached_state = NULL;
M
Miao Xie 已提交
4194
	u64 start = page_offset(page);
4195 4196 4197
	u64 end = start + PAGE_CACHE_SIZE - 1;
	size_t blocksize = page->mapping->host->i_sb->s_blocksize;

4198
	start += ALIGN(offset, blocksize);
4199 4200 4201
	if (start > end)
		return 0;

4202
	lock_extent_bits(tree, start, end, 0, &cached_state);
4203
	wait_on_page_writeback(page);
4204
	clear_extent_bit(tree, start, end,
4205 4206
			 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
			 EXTENT_DO_ACCOUNTING,
4207
			 1, 1, &cached_state, GFP_NOFS);
4208 4209 4210
	return 0;
}

4211 4212 4213 4214 4215
/*
 * a helper for releasepage, this tests for areas of the page that
 * are locked or under IO and drops the related state bits if it is safe
 * to drop the page.
 */
4216 4217 4218
static int try_release_extent_state(struct extent_map_tree *map,
				    struct extent_io_tree *tree,
				    struct page *page, gfp_t mask)
4219
{
M
Miao Xie 已提交
4220
	u64 start = page_offset(page);
4221 4222 4223
	u64 end = start + PAGE_CACHE_SIZE - 1;
	int ret = 1;

4224
	if (test_range_bit(tree, start, end,
4225
			   EXTENT_IOBITS, 0, NULL))
4226 4227 4228 4229
		ret = 0;
	else {
		if ((mask & GFP_NOFS) == GFP_NOFS)
			mask = GFP_NOFS;
4230 4231 4232 4233
		/*
		 * at this point we can safely clear everything except the
		 * locked bit and the nodatasum bit
		 */
4234
		ret = clear_extent_bit(tree, start, end,
4235 4236
				 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
				 0, 0, NULL, mask);
4237 4238 4239 4240 4241 4242 4243 4244

		/* if clear_extent_bit failed for enomem reasons,
		 * we can't allow the release to continue.
		 */
		if (ret < 0)
			ret = 0;
		else
			ret = 1;
4245 4246 4247 4248
	}
	return ret;
}

4249 4250 4251 4252 4253 4254
/*
 * a helper for releasepage.  As long as there are no locked extents
 * in the range corresponding to the page, both state records and extent
 * map records are removed
 */
int try_release_extent_mapping(struct extent_map_tree *map,
4255 4256
			       struct extent_io_tree *tree, struct page *page,
			       gfp_t mask)
4257 4258
{
	struct extent_map *em;
M
Miao Xie 已提交
4259
	u64 start = page_offset(page);
4260
	u64 end = start + PAGE_CACHE_SIZE - 1;
4261

4262 4263
	if ((mask & __GFP_WAIT) &&
	    page->mapping->host->i_size > 16 * 1024 * 1024) {
4264
		u64 len;
4265
		while (start <= end) {
4266
			len = end - start + 1;
4267
			write_lock(&map->lock);
4268
			em = lookup_extent_mapping(map, start, len);
4269
			if (!em) {
4270
				write_unlock(&map->lock);
4271 4272
				break;
			}
4273 4274
			if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
			    em->start != start) {
4275
				write_unlock(&map->lock);
4276 4277 4278 4279 4280
				free_extent_map(em);
				break;
			}
			if (!test_range_bit(tree, em->start,
					    extent_map_end(em) - 1,
4281
					    EXTENT_LOCKED | EXTENT_WRITEBACK,
4282
					    0, NULL)) {
4283 4284 4285 4286 4287
				remove_extent_mapping(map, em);
				/* once for the rb tree */
				free_extent_map(em);
			}
			start = extent_map_end(em);
4288
			write_unlock(&map->lock);
4289 4290

			/* once for us */
4291 4292 4293
			free_extent_map(em);
		}
	}
4294
	return try_release_extent_state(map, tree, page, mask);
4295 4296
}

4297 4298 4299 4300 4301 4302 4303 4304 4305 4306 4307 4308 4309 4310 4311 4312
/*
 * helper function for fiemap, which doesn't want to see any holes.
 * This maps until we find something past 'last'
 */
static struct extent_map *get_extent_skip_holes(struct inode *inode,
						u64 offset,
						u64 last,
						get_extent_t *get_extent)
{
	u64 sectorsize = BTRFS_I(inode)->root->sectorsize;
	struct extent_map *em;
	u64 len;

	if (offset >= last)
		return NULL;

4313
	while (1) {
4314 4315 4316
		len = last - offset;
		if (len == 0)
			break;
4317
		len = ALIGN(len, sectorsize);
4318
		em = get_extent(inode, NULL, 0, offset, len, 0);
4319
		if (IS_ERR_OR_NULL(em))
4320 4321 4322 4323 4324 4325 4326 4327 4328 4329 4330 4331 4332 4333 4334 4335 4336
			return em;

		/* if this isn't a hole return it */
		if (!test_bit(EXTENT_FLAG_VACANCY, &em->flags) &&
		    em->block_start != EXTENT_MAP_HOLE) {
			return em;
		}

		/* this is a hole, advance to the next extent */
		offset = extent_map_end(em);
		free_extent_map(em);
		if (offset >= last)
			break;
	}
	return NULL;
}

Y
Yehuda Sadeh 已提交
4337 4338 4339
int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
		__u64 start, __u64 len, get_extent_t *get_extent)
{
J
Josef Bacik 已提交
4340
	int ret = 0;
Y
Yehuda Sadeh 已提交
4341 4342 4343
	u64 off = start;
	u64 max = start + len;
	u32 flags = 0;
J
Josef Bacik 已提交
4344 4345
	u32 found_type;
	u64 last;
4346
	u64 last_for_get_extent = 0;
Y
Yehuda Sadeh 已提交
4347
	u64 disko = 0;
4348
	u64 isize = i_size_read(inode);
J
Josef Bacik 已提交
4349
	struct btrfs_key found_key;
Y
Yehuda Sadeh 已提交
4350
	struct extent_map *em = NULL;
4351
	struct extent_state *cached_state = NULL;
J
Josef Bacik 已提交
4352
	struct btrfs_path *path;
4353
	struct btrfs_root *root = BTRFS_I(inode)->root;
Y
Yehuda Sadeh 已提交
4354
	int end = 0;
4355 4356 4357
	u64 em_start = 0;
	u64 em_len = 0;
	u64 em_end = 0;
Y
Yehuda Sadeh 已提交
4358 4359 4360 4361

	if (len == 0)
		return -EINVAL;

J
Josef Bacik 已提交
4362 4363 4364 4365 4366
	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
	path->leave_spinning = 1;

4367 4368
	start = round_down(start, BTRFS_I(inode)->root->sectorsize);
	len = round_up(max, BTRFS_I(inode)->root->sectorsize) - start;
4369

4370 4371 4372 4373
	/*
	 * lookup the last file extent.  We're not using i_size here
	 * because there might be preallocation past i_size
	 */
4374 4375
	ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode), -1,
				       0);
J
Josef Bacik 已提交
4376 4377 4378 4379 4380 4381 4382
	if (ret < 0) {
		btrfs_free_path(path);
		return ret;
	}
	WARN_ON(!ret);
	path->slots[0]--;
	btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
4383
	found_type = found_key.type;
J
Josef Bacik 已提交
4384

4385
	/* No extents, but there might be delalloc bits */
L
Li Zefan 已提交
4386
	if (found_key.objectid != btrfs_ino(inode) ||
J
Josef Bacik 已提交
4387
	    found_type != BTRFS_EXTENT_DATA_KEY) {
4388 4389 4390 4391 4392 4393 4394 4395 4396 4397 4398
		/* have to trust i_size as the end */
		last = (u64)-1;
		last_for_get_extent = isize;
	} else {
		/*
		 * remember the start of the last extent.  There are a
		 * bunch of different factors that go into the length of the
		 * extent, so its much less complex to remember where it started
		 */
		last = found_key.offset;
		last_for_get_extent = last + 1;
J
Josef Bacik 已提交
4399
	}
4400
	btrfs_release_path(path);
J
Josef Bacik 已提交
4401

4402 4403 4404 4405 4406 4407 4408 4409 4410 4411
	/*
	 * we might have some extents allocated but more delalloc past those
	 * extents.  so, we trust isize unless the start of the last extent is
	 * beyond isize
	 */
	if (last < isize) {
		last = (u64)-1;
		last_for_get_extent = isize;
	}

L
Liu Bo 已提交
4412
	lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len - 1, 0,
4413
			 &cached_state);
4414

4415
	em = get_extent_skip_holes(inode, start, last_for_get_extent,
4416
				   get_extent);
Y
Yehuda Sadeh 已提交
4417 4418 4419 4420 4421 4422
	if (!em)
		goto out;
	if (IS_ERR(em)) {
		ret = PTR_ERR(em);
		goto out;
	}
J
Josef Bacik 已提交
4423

Y
Yehuda Sadeh 已提交
4424
	while (!end) {
4425
		u64 offset_in_extent = 0;
4426 4427 4428 4429 4430 4431 4432 4433 4434 4435 4436 4437

		/* break if the extent we found is outside the range */
		if (em->start >= max || extent_map_end(em) < off)
			break;

		/*
		 * get_extent may return an extent that starts before our
		 * requested range.  We have to make sure the ranges
		 * we return to fiemap always move forward and don't
		 * overlap, so adjust the offsets here
		 */
		em_start = max(em->start, off);
Y
Yehuda Sadeh 已提交
4438

4439 4440
		/*
		 * record the offset from the start of the extent
4441 4442 4443
		 * for adjusting the disk offset below.  Only do this if the
		 * extent isn't compressed since our in ram offset may be past
		 * what we have actually allocated on disk.
4444
		 */
4445 4446
		if (!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
			offset_in_extent = em_start - em->start;
4447
		em_end = extent_map_end(em);
4448
		em_len = em_end - em_start;
Y
Yehuda Sadeh 已提交
4449 4450 4451
		disko = 0;
		flags = 0;

4452 4453 4454 4455 4456 4457 4458
		/*
		 * bump off for our next call to get_extent
		 */
		off = extent_map_end(em);
		if (off >= max)
			end = 1;

4459
		if (em->block_start == EXTENT_MAP_LAST_BYTE) {
Y
Yehuda Sadeh 已提交
4460 4461
			end = 1;
			flags |= FIEMAP_EXTENT_LAST;
4462
		} else if (em->block_start == EXTENT_MAP_INLINE) {
Y
Yehuda Sadeh 已提交
4463 4464
			flags |= (FIEMAP_EXTENT_DATA_INLINE |
				  FIEMAP_EXTENT_NOT_ALIGNED);
4465
		} else if (em->block_start == EXTENT_MAP_DELALLOC) {
Y
Yehuda Sadeh 已提交
4466 4467
			flags |= (FIEMAP_EXTENT_DELALLOC |
				  FIEMAP_EXTENT_UNKNOWN);
4468 4469 4470
		} else if (fieinfo->fi_extents_max) {
			u64 bytenr = em->block_start -
				(em->start - em->orig_start);
4471

4472
			disko = em->block_start + offset_in_extent;
4473 4474 4475 4476

			/*
			 * As btrfs supports shared space, this information
			 * can be exported to userspace tools via
4477 4478 4479
			 * flag FIEMAP_EXTENT_SHARED.  If fi_extents_max == 0
			 * then we're just getting a count and we can skip the
			 * lookup stuff.
4480
			 */
4481 4482 4483 4484
			ret = btrfs_check_shared(NULL, root->fs_info,
						 root->objectid,
						 btrfs_ino(inode), bytenr);
			if (ret < 0)
4485
				goto out_free;
4486
			if (ret)
4487
				flags |= FIEMAP_EXTENT_SHARED;
4488
			ret = 0;
Y
Yehuda Sadeh 已提交
4489 4490 4491
		}
		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
			flags |= FIEMAP_EXTENT_ENCODED;
4492 4493
		if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
			flags |= FIEMAP_EXTENT_UNWRITTEN;
Y
Yehuda Sadeh 已提交
4494 4495 4496

		free_extent_map(em);
		em = NULL;
4497 4498
		if ((em_start >= last) || em_len == (u64)-1 ||
		   (last == (u64)-1 && isize <= em_end)) {
Y
Yehuda Sadeh 已提交
4499 4500 4501 4502
			flags |= FIEMAP_EXTENT_LAST;
			end = 1;
		}

4503 4504 4505 4506 4507 4508 4509 4510
		/* now scan forward to see if this is really the last extent. */
		em = get_extent_skip_holes(inode, off, last_for_get_extent,
					   get_extent);
		if (IS_ERR(em)) {
			ret = PTR_ERR(em);
			goto out;
		}
		if (!em) {
J
Josef Bacik 已提交
4511 4512 4513
			flags |= FIEMAP_EXTENT_LAST;
			end = 1;
		}
4514 4515
		ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
					      em_len, flags);
4516 4517 4518
		if (ret) {
			if (ret == 1)
				ret = 0;
4519
			goto out_free;
4520
		}
Y
Yehuda Sadeh 已提交
4521 4522 4523 4524
	}
out_free:
	free_extent_map(em);
out:
4525
	btrfs_free_path(path);
L
Liu Bo 已提交
4526
	unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4527
			     &cached_state, GFP_NOFS);
Y
Yehuda Sadeh 已提交
4528 4529 4530
	return ret;
}

4531 4532
static void __free_extent_buffer(struct extent_buffer *eb)
{
4533
	btrfs_leak_debug_del(&eb->leak_list);
4534 4535 4536
	kmem_cache_free(extent_buffer_cache, eb);
}

4537
int extent_buffer_under_io(struct extent_buffer *eb)
4538 4539 4540 4541 4542 4543 4544 4545 4546
{
	return (atomic_read(&eb->io_pages) ||
		test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
		test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
}

/*
 * Helper for releasing extent buffer page.
 */
4547
static void btrfs_release_extent_buffer_page(struct extent_buffer *eb)
4548 4549 4550 4551 4552 4553 4554
{
	unsigned long index;
	struct page *page;
	int mapped = !test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);

	BUG_ON(extent_buffer_under_io(eb));

4555 4556
	index = num_extent_pages(eb->start, eb->len);
	if (index == 0)
4557 4558 4559 4560
		return;

	do {
		index--;
4561
		page = eb->pages[index];
4562 4563 4564
		if (!page)
			continue;
		if (mapped)
4565
			spin_lock(&page->mapping->private_lock);
4566 4567 4568 4569 4570 4571 4572 4573 4574 4575 4576 4577
		/*
		 * We do this since we'll remove the pages after we've
		 * removed the eb from the radix tree, so we could race
		 * and have this page now attached to the new eb.  So
		 * only clear page_private if it's still connected to
		 * this eb.
		 */
		if (PagePrivate(page) &&
		    page->private == (unsigned long)eb) {
			BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
			BUG_ON(PageDirty(page));
			BUG_ON(PageWriteback(page));
4578
			/*
4579 4580
			 * We need to make sure we haven't be attached
			 * to a new eb.
4581
			 */
4582 4583 4584
			ClearPagePrivate(page);
			set_page_private(page, 0);
			/* One for the page private */
4585 4586
			page_cache_release(page);
		}
4587 4588 4589 4590 4591 4592

		if (mapped)
			spin_unlock(&page->mapping->private_lock);

		/* One for when we alloced the page */
		page_cache_release(page);
4593
	} while (index != 0);
4594 4595 4596 4597 4598 4599 4600
}

/*
 * Helper for releasing the extent buffer.
 */
static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
{
4601
	btrfs_release_extent_buffer_page(eb);
4602 4603 4604
	__free_extent_buffer(eb);
}

4605 4606
static struct extent_buffer *
__alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
4607
		      unsigned long len)
4608 4609 4610
{
	struct extent_buffer *eb = NULL;

4611
	eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS);
T
Tsutomu Itoh 已提交
4612 4613
	if (eb == NULL)
		return NULL;
4614 4615
	eb->start = start;
	eb->len = len;
4616
	eb->fs_info = fs_info;
4617
	eb->bflags = 0;
4618 4619 4620 4621 4622 4623 4624
	rwlock_init(&eb->lock);
	atomic_set(&eb->write_locks, 0);
	atomic_set(&eb->read_locks, 0);
	atomic_set(&eb->blocking_readers, 0);
	atomic_set(&eb->blocking_writers, 0);
	atomic_set(&eb->spinning_readers, 0);
	atomic_set(&eb->spinning_writers, 0);
4625
	eb->lock_nested = 0;
4626 4627
	init_waitqueue_head(&eb->write_lock_wq);
	init_waitqueue_head(&eb->read_lock_wq);
4628

4629 4630
	btrfs_leak_debug_add(&eb->leak_list, &buffers);

4631
	spin_lock_init(&eb->refs_lock);
4632
	atomic_set(&eb->refs, 1);
4633
	atomic_set(&eb->io_pages, 0);
4634

4635 4636 4637 4638 4639 4640
	/*
	 * Sanity checks, currently the maximum is 64k covered by 16x 4k pages
	 */
	BUILD_BUG_ON(BTRFS_MAX_METADATA_BLOCKSIZE
		> MAX_INLINE_EXTENT_BUFFER_SIZE);
	BUG_ON(len > MAX_INLINE_EXTENT_BUFFER_SIZE);
4641 4642 4643 4644

	return eb;
}

4645 4646 4647 4648 4649 4650 4651
struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src)
{
	unsigned long i;
	struct page *p;
	struct extent_buffer *new;
	unsigned long num_pages = num_extent_pages(src->start, src->len);

4652
	new = __alloc_extent_buffer(src->fs_info, src->start, src->len);
4653 4654 4655 4656
	if (new == NULL)
		return NULL;

	for (i = 0; i < num_pages; i++) {
4657
		p = alloc_page(GFP_NOFS);
4658 4659 4660 4661
		if (!p) {
			btrfs_release_extent_buffer(new);
			return NULL;
		}
4662 4663 4664 4665 4666 4667 4668 4669 4670 4671 4672 4673 4674
		attach_extent_buffer_page(new, p);
		WARN_ON(PageDirty(p));
		SetPageUptodate(p);
		new->pages[i] = p;
	}

	copy_extent_buffer(new, src, 0, 0, src->len);
	set_bit(EXTENT_BUFFER_UPTODATE, &new->bflags);
	set_bit(EXTENT_BUFFER_DUMMY, &new->bflags);

	return new;
}

4675 4676
struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
						u64 start)
4677 4678
{
	struct extent_buffer *eb;
4679 4680
	unsigned long len;
	unsigned long num_pages;
4681 4682
	unsigned long i;

4683 4684 4685 4686 4687 4688 4689 4690 4691 4692 4693 4694
	if (!fs_info) {
		/*
		 * Called only from tests that don't always have a fs_info
		 * available, but we know that nodesize is 4096
		 */
		len = 4096;
	} else {
		len = fs_info->tree_root->nodesize;
	}
	num_pages = num_extent_pages(0, len);

	eb = __alloc_extent_buffer(fs_info, start, len);
4695 4696 4697 4698
	if (!eb)
		return NULL;

	for (i = 0; i < num_pages; i++) {
4699
		eb->pages[i] = alloc_page(GFP_NOFS);
4700 4701 4702 4703 4704 4705 4706 4707 4708
		if (!eb->pages[i])
			goto err;
	}
	set_extent_buffer_uptodate(eb);
	btrfs_set_header_nritems(eb, 0);
	set_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);

	return eb;
err:
4709 4710
	for (; i > 0; i--)
		__free_page(eb->pages[i - 1]);
4711 4712 4713 4714
	__free_extent_buffer(eb);
	return NULL;
}

4715 4716
static void check_buffer_tree_ref(struct extent_buffer *eb)
{
4717
	int refs;
4718 4719 4720 4721 4722 4723 4724 4725 4726 4727 4728 4729 4730 4731 4732 4733 4734 4735 4736 4737
	/* the ref bit is tricky.  We have to make sure it is set
	 * if we have the buffer dirty.   Otherwise the
	 * code to free a buffer can end up dropping a dirty
	 * page
	 *
	 * Once the ref bit is set, it won't go away while the
	 * buffer is dirty or in writeback, and it also won't
	 * go away while we have the reference count on the
	 * eb bumped.
	 *
	 * We can't just set the ref bit without bumping the
	 * ref on the eb because free_extent_buffer might
	 * see the ref bit and try to clear it.  If this happens
	 * free_extent_buffer might end up dropping our original
	 * ref by mistake and freeing the page before we are able
	 * to add one more ref.
	 *
	 * So bump the ref count first, then set the bit.  If someone
	 * beat us to it, drop the ref we added.
	 */
4738 4739 4740 4741
	refs = atomic_read(&eb->refs);
	if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
		return;

4742 4743
	spin_lock(&eb->refs_lock);
	if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4744
		atomic_inc(&eb->refs);
4745
	spin_unlock(&eb->refs_lock);
4746 4747
}

4748 4749
static void mark_extent_buffer_accessed(struct extent_buffer *eb,
		struct page *accessed)
4750 4751 4752
{
	unsigned long num_pages, i;

4753 4754
	check_buffer_tree_ref(eb);

4755 4756
	num_pages = num_extent_pages(eb->start, eb->len);
	for (i = 0; i < num_pages; i++) {
4757 4758
		struct page *p = eb->pages[i];

4759 4760
		if (p != accessed)
			mark_page_accessed(p);
4761 4762 4763
	}
}

4764 4765
struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
					 u64 start)
4766 4767 4768 4769
{
	struct extent_buffer *eb;

	rcu_read_lock();
4770 4771
	eb = radix_tree_lookup(&fs_info->buffer_radix,
			       start >> PAGE_CACHE_SHIFT);
4772 4773
	if (eb && atomic_inc_not_zero(&eb->refs)) {
		rcu_read_unlock();
4774 4775 4776 4777 4778 4779 4780 4781 4782 4783 4784 4785 4786 4787 4788 4789 4790 4791 4792
		/*
		 * Lock our eb's refs_lock to avoid races with
		 * free_extent_buffer. When we get our eb it might be flagged
		 * with EXTENT_BUFFER_STALE and another task running
		 * free_extent_buffer might have seen that flag set,
		 * eb->refs == 2, that the buffer isn't under IO (dirty and
		 * writeback flags not set) and it's still in the tree (flag
		 * EXTENT_BUFFER_TREE_REF set), therefore being in the process
		 * of decrementing the extent buffer's reference count twice.
		 * So here we could race and increment the eb's reference count,
		 * clear its stale flag, mark it as dirty and drop our reference
		 * before the other task finishes executing free_extent_buffer,
		 * which would later result in an attempt to free an extent
		 * buffer that is dirty.
		 */
		if (test_bit(EXTENT_BUFFER_STALE, &eb->bflags)) {
			spin_lock(&eb->refs_lock);
			spin_unlock(&eb->refs_lock);
		}
4793
		mark_extent_buffer_accessed(eb, NULL);
4794 4795 4796 4797 4798 4799 4800
		return eb;
	}
	rcu_read_unlock();

	return NULL;
}

4801 4802
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
4803
					       u64 start)
4804 4805 4806 4807 4808 4809 4810
{
	struct extent_buffer *eb, *exists = NULL;
	int ret;

	eb = find_extent_buffer(fs_info, start);
	if (eb)
		return eb;
4811
	eb = alloc_dummy_extent_buffer(fs_info, start);
4812 4813 4814 4815 4816 4817 4818 4819 4820 4821 4822 4823 4824 4825 4826 4827 4828 4829 4830 4831 4832 4833 4834 4835 4836 4837 4838 4839 4840 4841 4842 4843 4844 4845 4846 4847
	if (!eb)
		return NULL;
	eb->fs_info = fs_info;
again:
	ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
	if (ret)
		goto free_eb;
	spin_lock(&fs_info->buffer_lock);
	ret = radix_tree_insert(&fs_info->buffer_radix,
				start >> PAGE_CACHE_SHIFT, eb);
	spin_unlock(&fs_info->buffer_lock);
	radix_tree_preload_end();
	if (ret == -EEXIST) {
		exists = find_extent_buffer(fs_info, start);
		if (exists)
			goto free_eb;
		else
			goto again;
	}
	check_buffer_tree_ref(eb);
	set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);

	/*
	 * We will free dummy extent buffer's if they come into
	 * free_extent_buffer with a ref count of 2, but if we are using this we
	 * want the buffers to stay in memory until we're done with them, so
	 * bump the ref count again.
	 */
	atomic_inc(&eb->refs);
	return eb;
free_eb:
	btrfs_release_extent_buffer(eb);
	return exists;
}
#endif

4848
struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
4849
					  u64 start)
4850
{
4851
	unsigned long len = fs_info->tree_root->nodesize;
4852 4853 4854 4855
	unsigned long num_pages = num_extent_pages(start, len);
	unsigned long i;
	unsigned long index = start >> PAGE_CACHE_SHIFT;
	struct extent_buffer *eb;
4856
	struct extent_buffer *exists = NULL;
4857
	struct page *p;
4858
	struct address_space *mapping = fs_info->btree_inode->i_mapping;
4859
	int uptodate = 1;
4860
	int ret;
4861

4862
	eb = find_extent_buffer(fs_info, start);
4863
	if (eb)
4864 4865
		return eb;

4866
	eb = __alloc_extent_buffer(fs_info, start, len);
4867
	if (!eb)
4868 4869
		return NULL;

4870
	for (i = 0; i < num_pages; i++, index++) {
4871
		p = find_or_create_page(mapping, index, GFP_NOFS);
4872
		if (!p)
4873
			goto free_eb;
J
Josef Bacik 已提交
4874 4875 4876 4877 4878 4879 4880 4881 4882 4883 4884 4885 4886 4887

		spin_lock(&mapping->private_lock);
		if (PagePrivate(p)) {
			/*
			 * We could have already allocated an eb for this page
			 * and attached one so lets see if we can get a ref on
			 * the existing eb, and if we can we know it's good and
			 * we can just return that one, else we know we can just
			 * overwrite page->private.
			 */
			exists = (struct extent_buffer *)p->private;
			if (atomic_inc_not_zero(&exists->refs)) {
				spin_unlock(&mapping->private_lock);
				unlock_page(p);
4888
				page_cache_release(p);
4889
				mark_extent_buffer_accessed(exists, p);
J
Josef Bacik 已提交
4890 4891
				goto free_eb;
			}
4892
			exists = NULL;
J
Josef Bacik 已提交
4893

4894
			/*
J
Josef Bacik 已提交
4895 4896 4897 4898
			 * Do this so attach doesn't complain and we need to
			 * drop the ref the old guy had.
			 */
			ClearPagePrivate(p);
4899
			WARN_ON(PageDirty(p));
J
Josef Bacik 已提交
4900
			page_cache_release(p);
4901
		}
J
Josef Bacik 已提交
4902 4903
		attach_extent_buffer_page(eb, p);
		spin_unlock(&mapping->private_lock);
4904
		WARN_ON(PageDirty(p));
4905
		eb->pages[i] = p;
4906 4907
		if (!PageUptodate(p))
			uptodate = 0;
C
Chris Mason 已提交
4908 4909 4910 4911 4912

		/*
		 * see below about how we avoid a nasty race with release page
		 * and why we unlock later
		 */
4913 4914
	}
	if (uptodate)
4915
		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4916
again:
4917 4918 4919 4920
	ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
	if (ret)
		goto free_eb;

4921 4922 4923 4924
	spin_lock(&fs_info->buffer_lock);
	ret = radix_tree_insert(&fs_info->buffer_radix,
				start >> PAGE_CACHE_SHIFT, eb);
	spin_unlock(&fs_info->buffer_lock);
4925
	radix_tree_preload_end();
4926
	if (ret == -EEXIST) {
4927
		exists = find_extent_buffer(fs_info, start);
4928 4929 4930
		if (exists)
			goto free_eb;
		else
4931
			goto again;
4932 4933
	}
	/* add one reference for the tree */
4934
	check_buffer_tree_ref(eb);
4935
	set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
C
Chris Mason 已提交
4936 4937 4938 4939 4940 4941 4942 4943 4944 4945

	/*
	 * there is a race where release page may have
	 * tried to find this extent buffer in the radix
	 * but failed.  It will tell the VM it is safe to
	 * reclaim the, and it will clear the page private bit.
	 * We must make sure to set the page private bit properly
	 * after the extent buffer is in the radix tree so
	 * it doesn't get lost
	 */
4946 4947
	SetPageChecked(eb->pages[0]);
	for (i = 1; i < num_pages; i++) {
4948
		p = eb->pages[i];
4949 4950 4951 4952
		ClearPageChecked(p);
		unlock_page(p);
	}
	unlock_page(eb->pages[0]);
4953 4954
	return eb;

4955
free_eb:
4956
	WARN_ON(!atomic_dec_and_test(&eb->refs));
4957 4958 4959 4960
	for (i = 0; i < num_pages; i++) {
		if (eb->pages[i])
			unlock_page(eb->pages[i]);
	}
C
Chris Mason 已提交
4961

4962
	btrfs_release_extent_buffer(eb);
4963
	return exists;
4964 4965
}

4966 4967 4968 4969 4970 4971 4972 4973 4974
static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
{
	struct extent_buffer *eb =
			container_of(head, struct extent_buffer, rcu_head);

	__free_extent_buffer(eb);
}

/* Expects to have eb->eb_lock already held */
4975
static int release_extent_buffer(struct extent_buffer *eb)
4976 4977 4978
{
	WARN_ON(atomic_read(&eb->refs) == 0);
	if (atomic_dec_and_test(&eb->refs)) {
4979
		if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
4980
			struct btrfs_fs_info *fs_info = eb->fs_info;
4981

4982
			spin_unlock(&eb->refs_lock);
4983

4984 4985
			spin_lock(&fs_info->buffer_lock);
			radix_tree_delete(&fs_info->buffer_radix,
4986
					  eb->start >> PAGE_CACHE_SHIFT);
4987
			spin_unlock(&fs_info->buffer_lock);
4988 4989
		} else {
			spin_unlock(&eb->refs_lock);
4990
		}
4991 4992

		/* Should be safe to release our pages at this point */
4993
		btrfs_release_extent_buffer_page(eb);
4994 4995 4996 4997 4998 4999
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
		if (unlikely(test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))) {
			__free_extent_buffer(eb);
			return 1;
		}
#endif
5000
		call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
5001
		return 1;
5002 5003
	}
	spin_unlock(&eb->refs_lock);
5004 5005

	return 0;
5006 5007
}

5008 5009
void free_extent_buffer(struct extent_buffer *eb)
{
5010 5011
	int refs;
	int old;
5012 5013 5014
	if (!eb)
		return;

5015 5016 5017 5018 5019 5020 5021 5022 5023
	while (1) {
		refs = atomic_read(&eb->refs);
		if (refs <= 3)
			break;
		old = atomic_cmpxchg(&eb->refs, refs, refs - 1);
		if (old == refs)
			return;
	}

5024
	spin_lock(&eb->refs_lock);
5025 5026 5027 5028
	if (atomic_read(&eb->refs) == 2 &&
	    test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))
		atomic_dec(&eb->refs);

5029 5030
	if (atomic_read(&eb->refs) == 2 &&
	    test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
5031
	    !extent_buffer_under_io(eb) &&
5032 5033 5034 5035 5036 5037 5038
	    test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
		atomic_dec(&eb->refs);

	/*
	 * I know this is terrible, but it's temporary until we stop tracking
	 * the uptodate bits and such for the extent buffers.
	 */
5039
	release_extent_buffer(eb);
5040 5041 5042 5043 5044
}

void free_extent_buffer_stale(struct extent_buffer *eb)
{
	if (!eb)
5045 5046
		return;

5047 5048 5049
	spin_lock(&eb->refs_lock);
	set_bit(EXTENT_BUFFER_STALE, &eb->bflags);

5050
	if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
5051 5052
	    test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
		atomic_dec(&eb->refs);
5053
	release_extent_buffer(eb);
5054 5055
}

5056
void clear_extent_buffer_dirty(struct extent_buffer *eb)
5057 5058 5059 5060 5061 5062 5063 5064
{
	unsigned long i;
	unsigned long num_pages;
	struct page *page;

	num_pages = num_extent_pages(eb->start, eb->len);

	for (i = 0; i < num_pages; i++) {
5065
		page = eb->pages[i];
5066
		if (!PageDirty(page))
C
Chris Mason 已提交
5067 5068
			continue;

5069
		lock_page(page);
C
Chris Mason 已提交
5070 5071
		WARN_ON(!PagePrivate(page));

5072
		clear_page_dirty_for_io(page);
5073
		spin_lock_irq(&page->mapping->tree_lock);
5074 5075 5076 5077 5078
		if (!PageDirty(page)) {
			radix_tree_tag_clear(&page->mapping->page_tree,
						page_index(page),
						PAGECACHE_TAG_DIRTY);
		}
5079
		spin_unlock_irq(&page->mapping->tree_lock);
5080
		ClearPageError(page);
5081
		unlock_page(page);
5082
	}
5083
	WARN_ON(atomic_read(&eb->refs) == 0);
5084 5085
}

5086
int set_extent_buffer_dirty(struct extent_buffer *eb)
5087 5088 5089
{
	unsigned long i;
	unsigned long num_pages;
5090
	int was_dirty = 0;
5091

5092 5093
	check_buffer_tree_ref(eb);

5094
	was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
5095

5096
	num_pages = num_extent_pages(eb->start, eb->len);
5097
	WARN_ON(atomic_read(&eb->refs) == 0);
5098 5099
	WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));

5100
	for (i = 0; i < num_pages; i++)
5101
		set_page_dirty(eb->pages[i]);
5102
	return was_dirty;
5103 5104
}

5105
int clear_extent_buffer_uptodate(struct extent_buffer *eb)
5106 5107 5108 5109 5110
{
	unsigned long i;
	struct page *page;
	unsigned long num_pages;

5111
	clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5112
	num_pages = num_extent_pages(eb->start, eb->len);
5113
	for (i = 0; i < num_pages; i++) {
5114
		page = eb->pages[i];
C
Chris Mason 已提交
5115 5116
		if (page)
			ClearPageUptodate(page);
5117 5118 5119 5120
	}
	return 0;
}

5121
int set_extent_buffer_uptodate(struct extent_buffer *eb)
5122 5123 5124 5125 5126
{
	unsigned long i;
	struct page *page;
	unsigned long num_pages;

5127
	set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5128 5129
	num_pages = num_extent_pages(eb->start, eb->len);
	for (i = 0; i < num_pages; i++) {
5130
		page = eb->pages[i];
5131 5132 5133 5134 5135
		SetPageUptodate(page);
	}
	return 0;
}

5136
int extent_buffer_uptodate(struct extent_buffer *eb)
5137
{
5138
	return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5139 5140 5141
}

int read_extent_buffer_pages(struct extent_io_tree *tree,
5142
			     struct extent_buffer *eb, u64 start, int wait,
5143
			     get_extent_t *get_extent, int mirror_num)
5144 5145 5146 5147 5148 5149
{
	unsigned long i;
	unsigned long start_i;
	struct page *page;
	int err;
	int ret = 0;
5150 5151
	int locked_pages = 0;
	int all_uptodate = 1;
5152
	unsigned long num_pages;
5153
	unsigned long num_reads = 0;
5154
	struct bio *bio = NULL;
C
Chris Mason 已提交
5155
	unsigned long bio_flags = 0;
5156

5157
	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
5158 5159 5160 5161 5162 5163 5164 5165 5166 5167 5168 5169
		return 0;

	if (start) {
		WARN_ON(start < eb->start);
		start_i = (start >> PAGE_CACHE_SHIFT) -
			(eb->start >> PAGE_CACHE_SHIFT);
	} else {
		start_i = 0;
	}

	num_pages = num_extent_pages(eb->start, eb->len);
	for (i = start_i; i < num_pages; i++) {
5170
		page = eb->pages[i];
5171
		if (wait == WAIT_NONE) {
5172
			if (!trylock_page(page))
5173
				goto unlock_exit;
5174 5175 5176
		} else {
			lock_page(page);
		}
5177
		locked_pages++;
5178 5179
		if (!PageUptodate(page)) {
			num_reads++;
5180
			all_uptodate = 0;
5181
		}
5182 5183 5184
	}
	if (all_uptodate) {
		if (start_i == 0)
5185
			set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5186 5187 5188
		goto unlock_exit;
	}

5189
	clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
5190
	eb->read_mirror = 0;
5191
	atomic_set(&eb->io_pages, num_reads);
5192
	for (i = start_i; i < num_pages; i++) {
5193
		page = eb->pages[i];
5194
		if (!PageUptodate(page)) {
5195
			ClearPageError(page);
5196
			err = __extent_read_full_page(tree, page,
5197
						      get_extent, &bio,
5198 5199
						      mirror_num, &bio_flags,
						      READ | REQ_META);
C
Chris Mason 已提交
5200
			if (err)
5201 5202 5203 5204 5205 5206
				ret = err;
		} else {
			unlock_page(page);
		}
	}

5207
	if (bio) {
5208 5209
		err = submit_one_bio(READ | REQ_META, bio, mirror_num,
				     bio_flags);
5210 5211
		if (err)
			return err;
5212
	}
5213

5214
	if (ret || wait != WAIT_COMPLETE)
5215
		return ret;
C
Chris Mason 已提交
5216

5217
	for (i = start_i; i < num_pages; i++) {
5218
		page = eb->pages[i];
5219
		wait_on_page_locked(page);
C
Chris Mason 已提交
5220
		if (!PageUptodate(page))
5221 5222
			ret = -EIO;
	}
C
Chris Mason 已提交
5223

5224
	return ret;
5225 5226 5227

unlock_exit:
	i = start_i;
C
Chris Mason 已提交
5228
	while (locked_pages > 0) {
5229
		page = eb->pages[i];
5230 5231 5232 5233 5234
		i++;
		unlock_page(page);
		locked_pages--;
	}
	return ret;
5235 5236 5237 5238 5239 5240 5241 5242 5243 5244 5245 5246 5247 5248 5249 5250 5251
}

void read_extent_buffer(struct extent_buffer *eb, void *dstv,
			unsigned long start,
			unsigned long len)
{
	size_t cur;
	size_t offset;
	struct page *page;
	char *kaddr;
	char *dst = (char *)dstv;
	size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
	unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;

	WARN_ON(start > eb->len);
	WARN_ON(start + len > eb->start + eb->len);

5252
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5253

C
Chris Mason 已提交
5254
	while (len > 0) {
5255
		page = eb->pages[i];
5256 5257

		cur = min(len, (PAGE_CACHE_SIZE - offset));
5258
		kaddr = page_address(page);
5259 5260 5261 5262 5263 5264 5265 5266 5267
		memcpy(dst, kaddr + offset, cur);

		dst += cur;
		len -= cur;
		offset = 0;
		i++;
	}
}

5268 5269 5270 5271 5272 5273 5274 5275 5276 5277 5278 5279 5280 5281 5282 5283 5284 5285 5286
int read_extent_buffer_to_user(struct extent_buffer *eb, void __user *dstv,
			unsigned long start,
			unsigned long len)
{
	size_t cur;
	size_t offset;
	struct page *page;
	char *kaddr;
	char __user *dst = (char __user *)dstv;
	size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
	unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
	int ret = 0;

	WARN_ON(start > eb->len);
	WARN_ON(start + len > eb->start + eb->len);

	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);

	while (len > 0) {
5287
		page = eb->pages[i];
5288 5289 5290 5291 5292 5293 5294 5295 5296 5297 5298 5299 5300 5301 5302 5303 5304

		cur = min(len, (PAGE_CACHE_SIZE - offset));
		kaddr = page_address(page);
		if (copy_to_user(dst, kaddr + offset, cur)) {
			ret = -EFAULT;
			break;
		}

		dst += cur;
		len -= cur;
		offset = 0;
		i++;
	}

	return ret;
}

5305
int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
5306
			       unsigned long min_len, char **map,
5307
			       unsigned long *map_start,
5308
			       unsigned long *map_len)
5309 5310 5311 5312 5313 5314 5315 5316 5317 5318 5319 5320 5321 5322 5323 5324 5325 5326 5327
{
	size_t offset = start & (PAGE_CACHE_SIZE - 1);
	char *kaddr;
	struct page *p;
	size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
	unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
	unsigned long end_i = (start_offset + start + min_len - 1) >>
		PAGE_CACHE_SHIFT;

	if (i != end_i)
		return -EINVAL;

	if (i == 0) {
		offset = start_offset;
		*map_start = 0;
	} else {
		offset = 0;
		*map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset;
	}
C
Chris Mason 已提交
5328

5329
	if (start + min_len > eb->len) {
J
Julia Lawall 已提交
5330
		WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
5331 5332
		       "wanted %lu %lu\n",
		       eb->start, eb->len, start, min_len);
5333
		return -EINVAL;
5334 5335
	}

5336
	p = eb->pages[i];
5337
	kaddr = page_address(p);
5338 5339 5340 5341 5342 5343 5344 5345 5346 5347 5348 5349 5350 5351 5352 5353 5354 5355 5356 5357 5358
	*map = kaddr + offset;
	*map_len = PAGE_CACHE_SIZE - offset;
	return 0;
}

int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
			  unsigned long start,
			  unsigned long len)
{
	size_t cur;
	size_t offset;
	struct page *page;
	char *kaddr;
	char *ptr = (char *)ptrv;
	size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
	unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
	int ret = 0;

	WARN_ON(start > eb->len);
	WARN_ON(start + len > eb->start + eb->len);

5359
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5360

C
Chris Mason 已提交
5361
	while (len > 0) {
5362
		page = eb->pages[i];
5363 5364 5365

		cur = min(len, (PAGE_CACHE_SIZE - offset));

5366
		kaddr = page_address(page);
5367 5368 5369 5370 5371 5372 5373 5374 5375 5376 5377 5378 5379 5380 5381 5382 5383 5384 5385 5386 5387 5388 5389 5390 5391 5392
		ret = memcmp(ptr, kaddr + offset, cur);
		if (ret)
			break;

		ptr += cur;
		len -= cur;
		offset = 0;
		i++;
	}
	return ret;
}

void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
			 unsigned long start, unsigned long len)
{
	size_t cur;
	size_t offset;
	struct page *page;
	char *kaddr;
	char *src = (char *)srcv;
	size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
	unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;

	WARN_ON(start > eb->len);
	WARN_ON(start + len > eb->start + eb->len);

5393
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5394

C
Chris Mason 已提交
5395
	while (len > 0) {
5396
		page = eb->pages[i];
5397 5398 5399
		WARN_ON(!PageUptodate(page));

		cur = min(len, PAGE_CACHE_SIZE - offset);
5400
		kaddr = page_address(page);
5401 5402 5403 5404 5405 5406 5407 5408 5409 5410 5411 5412 5413 5414 5415 5416 5417 5418 5419 5420 5421 5422
		memcpy(kaddr + offset, src, cur);

		src += cur;
		len -= cur;
		offset = 0;
		i++;
	}
}

void memset_extent_buffer(struct extent_buffer *eb, char c,
			  unsigned long start, unsigned long len)
{
	size_t cur;
	size_t offset;
	struct page *page;
	char *kaddr;
	size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
	unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;

	WARN_ON(start > eb->len);
	WARN_ON(start + len > eb->start + eb->len);

5423
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5424

C
Chris Mason 已提交
5425
	while (len > 0) {
5426
		page = eb->pages[i];
5427 5428 5429
		WARN_ON(!PageUptodate(page));

		cur = min(len, PAGE_CACHE_SIZE - offset);
5430
		kaddr = page_address(page);
5431 5432 5433 5434 5435 5436 5437 5438 5439 5440 5441 5442 5443 5444 5445 5446 5447 5448 5449 5450 5451 5452 5453
		memset(kaddr + offset, c, cur);

		len -= cur;
		offset = 0;
		i++;
	}
}

void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
			unsigned long dst_offset, unsigned long src_offset,
			unsigned long len)
{
	u64 dst_len = dst->len;
	size_t cur;
	size_t offset;
	struct page *page;
	char *kaddr;
	size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
	unsigned long i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;

	WARN_ON(src->len != dst_len);

	offset = (start_offset + dst_offset) &
5454
		(PAGE_CACHE_SIZE - 1);
5455

C
Chris Mason 已提交
5456
	while (len > 0) {
5457
		page = dst->pages[i];
5458 5459 5460 5461
		WARN_ON(!PageUptodate(page));

		cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));

5462
		kaddr = page_address(page);
5463 5464 5465 5466 5467 5468 5469 5470 5471
		read_extent_buffer(src, kaddr + offset, src_offset, cur);

		src_offset += cur;
		len -= cur;
		offset = 0;
		i++;
	}
}

5472 5473 5474 5475 5476 5477
static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
{
	unsigned long distance = (src > dst) ? src - dst : dst - src;
	return distance < len;
}

5478 5479 5480 5481
static void copy_pages(struct page *dst_page, struct page *src_page,
		       unsigned long dst_off, unsigned long src_off,
		       unsigned long len)
{
5482
	char *dst_kaddr = page_address(dst_page);
5483
	char *src_kaddr;
5484
	int must_memmove = 0;
5485

5486
	if (dst_page != src_page) {
5487
		src_kaddr = page_address(src_page);
5488
	} else {
5489
		src_kaddr = dst_kaddr;
5490 5491
		if (areas_overlap(src_off, dst_off, len))
			must_memmove = 1;
5492
	}
5493

5494 5495 5496 5497
	if (must_memmove)
		memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
	else
		memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
5498 5499 5500 5501 5502 5503 5504 5505 5506 5507 5508 5509 5510
}

void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
			   unsigned long src_offset, unsigned long len)
{
	size_t cur;
	size_t dst_off_in_page;
	size_t src_off_in_page;
	size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
	unsigned long dst_i;
	unsigned long src_i;

	if (src_offset + len > dst->len) {
5511
		printk(KERN_ERR "BTRFS: memmove bogus src_offset %lu move "
C
Chris Mason 已提交
5512
		       "len %lu dst len %lu\n", src_offset, len, dst->len);
5513 5514 5515
		BUG_ON(1);
	}
	if (dst_offset + len > dst->len) {
5516
		printk(KERN_ERR "BTRFS: memmove bogus dst_offset %lu move "
C
Chris Mason 已提交
5517
		       "len %lu dst len %lu\n", dst_offset, len, dst->len);
5518 5519 5520
		BUG_ON(1);
	}

C
Chris Mason 已提交
5521
	while (len > 0) {
5522
		dst_off_in_page = (start_offset + dst_offset) &
5523
			(PAGE_CACHE_SIZE - 1);
5524
		src_off_in_page = (start_offset + src_offset) &
5525
			(PAGE_CACHE_SIZE - 1);
5526 5527 5528 5529 5530 5531 5532 5533 5534

		dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT;
		src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT;

		cur = min(len, (unsigned long)(PAGE_CACHE_SIZE -
					       src_off_in_page));
		cur = min_t(unsigned long, cur,
			(unsigned long)(PAGE_CACHE_SIZE - dst_off_in_page));

5535
		copy_pages(dst->pages[dst_i], dst->pages[src_i],
5536 5537 5538 5539 5540 5541 5542 5543 5544 5545 5546 5547 5548 5549 5550 5551 5552 5553 5554 5555 5556
			   dst_off_in_page, src_off_in_page, cur);

		src_offset += cur;
		dst_offset += cur;
		len -= cur;
	}
}

void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
			   unsigned long src_offset, unsigned long len)
{
	size_t cur;
	size_t dst_off_in_page;
	size_t src_off_in_page;
	unsigned long dst_end = dst_offset + len - 1;
	unsigned long src_end = src_offset + len - 1;
	size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1);
	unsigned long dst_i;
	unsigned long src_i;

	if (src_offset + len > dst->len) {
5557
		printk(KERN_ERR "BTRFS: memmove bogus src_offset %lu move "
C
Chris Mason 已提交
5558
		       "len %lu len %lu\n", src_offset, len, dst->len);
5559 5560 5561
		BUG_ON(1);
	}
	if (dst_offset + len > dst->len) {
5562
		printk(KERN_ERR "BTRFS: memmove bogus dst_offset %lu move "
C
Chris Mason 已提交
5563
		       "len %lu len %lu\n", dst_offset, len, dst->len);
5564 5565
		BUG_ON(1);
	}
5566
	if (dst_offset < src_offset) {
5567 5568 5569
		memcpy_extent_buffer(dst, dst_offset, src_offset, len);
		return;
	}
C
Chris Mason 已提交
5570
	while (len > 0) {
5571 5572 5573 5574
		dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT;
		src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT;

		dst_off_in_page = (start_offset + dst_end) &
5575
			(PAGE_CACHE_SIZE - 1);
5576
		src_off_in_page = (start_offset + src_end) &
5577
			(PAGE_CACHE_SIZE - 1);
5578 5579 5580

		cur = min_t(unsigned long, len, src_off_in_page + 1);
		cur = min(cur, dst_off_in_page + 1);
5581
		copy_pages(dst->pages[dst_i], dst->pages[src_i],
5582 5583 5584 5585 5586 5587 5588 5589
			   dst_off_in_page - cur + 1,
			   src_off_in_page - cur + 1, cur);

		dst_end -= cur;
		src_end -= cur;
		len -= cur;
	}
}
5590

5591
int try_release_extent_buffer(struct page *page)
5592
{
5593 5594
	struct extent_buffer *eb;

5595 5596 5597 5598 5599 5600 5601
	/*
	 * We need to make sure noboody is attaching this page to an eb right
	 * now.
	 */
	spin_lock(&page->mapping->private_lock);
	if (!PagePrivate(page)) {
		spin_unlock(&page->mapping->private_lock);
J
Josef Bacik 已提交
5602
		return 1;
5603
	}
5604

5605 5606
	eb = (struct extent_buffer *)page->private;
	BUG_ON(!eb);
5607 5608

	/*
5609 5610 5611
	 * This is a little awful but should be ok, we need to make sure that
	 * the eb doesn't disappear out from under us while we're looking at
	 * this page.
5612
	 */
5613
	spin_lock(&eb->refs_lock);
5614
	if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
5615 5616 5617
		spin_unlock(&eb->refs_lock);
		spin_unlock(&page->mapping->private_lock);
		return 0;
5618
	}
5619
	spin_unlock(&page->mapping->private_lock);
5620

5621
	/*
5622 5623
	 * If tree ref isn't set then we know the ref on this eb is a real ref,
	 * so just return, this page will likely be freed soon anyway.
5624
	 */
5625 5626 5627
	if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
		spin_unlock(&eb->refs_lock);
		return 0;
5628
	}
5629

5630
	return release_extent_buffer(eb);
5631
}