extent_io.c 140.3 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);
}

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#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),
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		       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)
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{
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	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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{
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	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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	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
{
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	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,
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			   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);
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		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;

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	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.
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 */
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)
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{
	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
	return clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask);
1281 1282 1283
}

int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
1284
			struct extent_state **cached_state, gfp_t mask)
1285 1286
{
	return set_extent_bit(tree, start, end,
1287
			      EXTENT_DELALLOC | EXTENT_UPTODATE,
J
Jeff Mahoney 已提交
1288
			      NULL, cached_state, mask);
1289 1290
}

1291 1292 1293 1294 1295 1296 1297 1298
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);
}

1299 1300 1301 1302
int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
		       gfp_t mask)
{
	return clear_extent_bit(tree, start, end,
1303
				EXTENT_DIRTY | EXTENT_DELALLOC |
1304
				EXTENT_DO_ACCOUNTING, 0, 0, NULL, mask);
1305 1306 1307 1308 1309
}

int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
		     gfp_t mask)
{
J
Jeff Mahoney 已提交
1310
	return set_extent_bit(tree, start, end, EXTENT_NEW, NULL,
1311
			      NULL, mask);
1312 1313 1314
}

int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
1315
			struct extent_state **cached_state, gfp_t mask)
1316
{
L
Liu Bo 已提交
1317
	return set_extent_bit(tree, start, end, EXTENT_UPTODATE, NULL,
J
Jeff Mahoney 已提交
1318
			      cached_state, mask);
1319 1320
}

1321 1322
int clear_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
			  struct extent_state **cached_state, gfp_t mask)
1323
{
1324
	return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
1325
				cached_state, mask);
1326 1327
}

C
Chris Mason 已提交
1328 1329 1330 1331
/*
 * either insert or lock state struct between start and end use mask to tell
 * us if waiting is desired.
 */
1332
int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1333
		     unsigned bits, struct extent_state **cached_state)
1334 1335 1336
{
	int err;
	u64 failed_start;
1337

1338
	while (1) {
J
Jeff Mahoney 已提交
1339 1340 1341
		err = __set_extent_bit(tree, start, end, EXTENT_LOCKED | bits,
				       EXTENT_LOCKED, &failed_start,
				       cached_state, GFP_NOFS);
1342
		if (err == -EEXIST) {
1343 1344
			wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
			start = failed_start;
1345
		} else
1346 1347 1348 1349 1350 1351
			break;
		WARN_ON(start > end);
	}
	return err;
}

1352
int lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1353
{
1354
	return lock_extent_bits(tree, start, end, 0, NULL);
1355 1356
}

1357
int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1358 1359 1360 1361
{
	int err;
	u64 failed_start;

J
Jeff Mahoney 已提交
1362 1363
	err = __set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
			       &failed_start, NULL, GFP_NOFS);
Y
Yan Zheng 已提交
1364 1365 1366
	if (err == -EEXIST) {
		if (failed_start > start)
			clear_extent_bit(tree, start, failed_start - 1,
1367
					 EXTENT_LOCKED, 1, 0, NULL, GFP_NOFS);
1368
		return 0;
Y
Yan Zheng 已提交
1369
	}
1370 1371 1372
	return 1;
}

1373 1374 1375 1376 1377 1378 1379
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);
}

1380
int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1381
{
1382
	return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
1383
				GFP_NOFS);
1384 1385
}

1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411
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);
1412
		account_page_redirty(page);
1413 1414 1415 1416 1417 1418
		page_cache_release(page);
		index++;
	}
	return 0;
}

1419 1420 1421
/*
 * helper function to set both pages and extents in the tree writeback
 */
1422
static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1423 1424 1425 1426 1427 1428 1429
{
	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);
1430
		BUG_ON(!page); /* Pages should be in the extent_io_tree */
1431 1432 1433 1434 1435 1436 1437
		set_page_writeback(page);
		page_cache_release(page);
		index++;
	}
	return 0;
}

C
Chris Mason 已提交
1438 1439 1440 1441
/* 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'
 */
1442 1443
static struct extent_state *
find_first_extent_bit_state(struct extent_io_tree *tree,
1444
			    u64 start, unsigned bits)
C
Chris Mason 已提交
1445 1446 1447 1448 1449 1450 1451 1452 1453
{
	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
1454
	if (!node)
C
Chris Mason 已提交
1455 1456
		goto out;

C
Chris Mason 已提交
1457
	while (1) {
C
Chris Mason 已提交
1458
		state = rb_entry(node, struct extent_state, rb_node);
C
Chris Mason 已提交
1459
		if (state->end >= start && (state->state & bits))
C
Chris Mason 已提交
1460
			return state;
C
Chris Mason 已提交
1461

C
Chris Mason 已提交
1462 1463 1464 1465 1466 1467 1468 1469
		node = rb_next(node);
		if (!node)
			break;
	}
out:
	return NULL;
}

1470 1471 1472 1473 1474
/*
 * 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.
 *
1475
 * If nothing was found, 1 is returned. If found something, return 0.
1476 1477
 */
int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1478
			  u64 *start_ret, u64 *end_ret, unsigned bits,
1479
			  struct extent_state **cached_state)
1480 1481
{
	struct extent_state *state;
1482
	struct rb_node *n;
1483 1484 1485
	int ret = 1;

	spin_lock(&tree->lock);
1486 1487
	if (cached_state && *cached_state) {
		state = *cached_state;
1488
		if (state->end == start - 1 && extent_state_in_tree(state)) {
1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504
			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;
	}

1505
	state = find_first_extent_bit_state(tree, start, bits);
1506
got_it:
1507
	if (state) {
1508
		cache_state_if_flags(state, cached_state, 0);
1509 1510 1511 1512
		*start_ret = state->start;
		*end_ret = state->end;
		ret = 0;
	}
1513
out:
1514 1515 1516 1517
	spin_unlock(&tree->lock);
	return ret;
}

C
Chris Mason 已提交
1518 1519 1520 1521 1522 1523
/*
 * 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
1524
static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1525 1526
					u64 *start, u64 *end, u64 max_bytes,
					struct extent_state **cached_state)
1527 1528 1529 1530 1531 1532 1533
{
	struct rb_node *node;
	struct extent_state *state;
	u64 cur_start = *start;
	u64 found = 0;
	u64 total_bytes = 0;

1534
	spin_lock(&tree->lock);
C
Chris Mason 已提交
1535

1536 1537 1538 1539
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1540
	node = tree_search(tree, cur_start);
1541
	if (!node) {
1542 1543
		if (!found)
			*end = (u64)-1;
1544 1545 1546
		goto out;
	}

C
Chris Mason 已提交
1547
	while (1) {
1548
		state = rb_entry(node, struct extent_state, rb_node);
1549 1550
		if (found && (state->start != cur_start ||
			      (state->state & EXTENT_BOUNDARY))) {
1551 1552 1553 1554 1555 1556 1557
			goto out;
		}
		if (!(state->state & EXTENT_DELALLOC)) {
			if (!found)
				*end = state->end;
			goto out;
		}
1558
		if (!found) {
1559
			*start = state->start;
1560 1561 1562
			*cached_state = state;
			atomic_inc(&state->refs);
		}
1563 1564 1565 1566 1567
		found++;
		*end = state->end;
		cur_start = state->end + 1;
		node = rb_next(node);
		total_bytes += state->end - state->start + 1;
1568
		if (total_bytes >= max_bytes)
1569 1570
			break;
		if (!node)
1571 1572 1573
			break;
	}
out:
1574
	spin_unlock(&tree->lock);
1575 1576 1577
	return found;
}

1578 1579 1580
static noinline void __unlock_for_delalloc(struct inode *inode,
					   struct page *locked_page,
					   u64 start, u64 end)
C
Chris Mason 已提交
1581 1582 1583 1584 1585 1586 1587 1588 1589
{
	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)
1590
		return;
C
Chris Mason 已提交
1591

C
Chris Mason 已提交
1592
	while (nr_pages > 0) {
C
Chris Mason 已提交
1593
		ret = find_get_pages_contig(inode->i_mapping, index,
1594 1595
				     min_t(unsigned long, nr_pages,
				     ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1596 1597 1598 1599 1600 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
		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
1627
	while (nrpages > 0) {
C
Chris Mason 已提交
1628
		ret = find_get_pages_contig(inode->i_mapping, index,
1629 1630
				     min_t(unsigned long,
				     nrpages, ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1631 1632 1633 1634 1635 1636 1637 1638 1639 1640
		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
			 */
1641
			if (pages[i] != locked_page) {
C
Chris Mason 已提交
1642
				lock_page(pages[i]);
1643 1644
				if (!PageDirty(pages[i]) ||
				    pages[i]->mapping != inode->i_mapping) {
1645 1646 1647 1648 1649 1650
					ret = -EAGAIN;
					unlock_page(pages[i]);
					page_cache_release(pages[i]);
					goto done;
				}
			}
C
Chris Mason 已提交
1651
			page_cache_release(pages[i]);
1652
			pages_locked++;
C
Chris Mason 已提交
1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674
		}
		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
 */
1675 1676 1677 1678
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
1679 1680 1681 1682
{
	u64 delalloc_start;
	u64 delalloc_end;
	u64 found;
1683
	struct extent_state *cached_state = NULL;
C
Chris Mason 已提交
1684 1685 1686 1687 1688 1689 1690 1691
	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,
1692
				    max_bytes, &cached_state);
C
Chris Mason 已提交
1693
	if (!found || delalloc_end <= *start) {
C
Chris Mason 已提交
1694 1695
		*start = delalloc_start;
		*end = delalloc_end;
1696
		free_extent_state(cached_state);
L
Liu Bo 已提交
1697
		return 0;
C
Chris Mason 已提交
1698 1699
	}

C
Chris Mason 已提交
1700 1701 1702 1703 1704
	/*
	 * 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
1705
	if (delalloc_start < *start)
C
Chris Mason 已提交
1706 1707
		delalloc_start = *start;

C
Chris Mason 已提交
1708 1709 1710
	/*
	 * make sure to limit the number of pages we try to lock down
	 */
1711 1712
	if (delalloc_end + 1 - delalloc_start > max_bytes)
		delalloc_end = delalloc_start + max_bytes - 1;
C
Chris Mason 已提交
1713

C
Chris Mason 已提交
1714 1715 1716 1717 1718 1719 1720
	/* 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
		 */
1721
		free_extent_state(cached_state);
1722
		cached_state = NULL;
C
Chris Mason 已提交
1723
		if (!loops) {
1724
			max_bytes = PAGE_CACHE_SIZE;
C
Chris Mason 已提交
1725 1726 1727 1728 1729 1730 1731
			loops = 1;
			goto again;
		} else {
			found = 0;
			goto out_failed;
		}
	}
1732
	BUG_ON(ret); /* Only valid values are 0 and -EAGAIN */
C
Chris Mason 已提交
1733 1734

	/* step three, lock the state bits for the whole range */
1735
	lock_extent_bits(tree, delalloc_start, delalloc_end, 0, &cached_state);
C
Chris Mason 已提交
1736 1737 1738

	/* then test to make sure it is all still delalloc */
	ret = test_range_bit(tree, delalloc_start, delalloc_end,
1739
			     EXTENT_DELALLOC, 1, cached_state);
C
Chris Mason 已提交
1740
	if (!ret) {
1741 1742
		unlock_extent_cached(tree, delalloc_start, delalloc_end,
				     &cached_state, GFP_NOFS);
C
Chris Mason 已提交
1743 1744 1745 1746 1747
		__unlock_for_delalloc(inode, locked_page,
			      delalloc_start, delalloc_end);
		cond_resched();
		goto again;
	}
1748
	free_extent_state(cached_state);
C
Chris Mason 已提交
1749 1750 1751 1752 1753 1754
	*start = delalloc_start;
	*end = delalloc_end;
out_failed:
	return found;
}

1755 1756
int extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
				 struct page *locked_page,
1757
				 unsigned clear_bits,
1758
				 unsigned long page_ops)
C
Chris Mason 已提交
1759
{
1760
	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
C
Chris Mason 已提交
1761 1762 1763 1764 1765 1766
	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;
1767

1768
	clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1769
	if (page_ops == 0)
1770
		return 0;
C
Chris Mason 已提交
1771

1772 1773 1774
	if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
		mapping_set_error(inode->i_mapping, -EIO);

C
Chris Mason 已提交
1775
	while (nr_pages > 0) {
C
Chris Mason 已提交
1776
		ret = find_get_pages_contig(inode->i_mapping, index,
1777 1778
				     min_t(unsigned long,
				     nr_pages, ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1779
		for (i = 0; i < ret; i++) {
1780

1781
			if (page_ops & PAGE_SET_PRIVATE2)
1782 1783
				SetPagePrivate2(pages[i]);

C
Chris Mason 已提交
1784 1785 1786 1787
			if (pages[i] == locked_page) {
				page_cache_release(pages[i]);
				continue;
			}
1788
			if (page_ops & PAGE_CLEAR_DIRTY)
C
Chris Mason 已提交
1789
				clear_page_dirty_for_io(pages[i]);
1790
			if (page_ops & PAGE_SET_WRITEBACK)
C
Chris Mason 已提交
1791
				set_page_writeback(pages[i]);
1792 1793
			if (page_ops & PAGE_SET_ERROR)
				SetPageError(pages[i]);
1794
			if (page_ops & PAGE_END_WRITEBACK)
C
Chris Mason 已提交
1795
				end_page_writeback(pages[i]);
1796
			if (page_ops & PAGE_UNLOCK)
1797
				unlock_page(pages[i]);
C
Chris Mason 已提交
1798 1799 1800 1801 1802 1803 1804 1805 1806
			page_cache_release(pages[i]);
		}
		nr_pages -= ret;
		index += ret;
		cond_resched();
	}
	return 0;
}

C
Chris Mason 已提交
1807 1808 1809 1810 1811
/*
 * 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.
 */
1812 1813
u64 count_range_bits(struct extent_io_tree *tree,
		     u64 *start, u64 search_end, u64 max_bytes,
1814
		     unsigned bits, int contig)
1815 1816 1817 1818 1819
{
	struct rb_node *node;
	struct extent_state *state;
	u64 cur_start = *start;
	u64 total_bytes = 0;
1820
	u64 last = 0;
1821 1822
	int found = 0;

1823
	if (WARN_ON(search_end <= cur_start))
1824 1825
		return 0;

1826
	spin_lock(&tree->lock);
1827 1828 1829 1830 1831 1832 1833 1834
	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.
	 */
1835
	node = tree_search(tree, cur_start);
C
Chris Mason 已提交
1836
	if (!node)
1837 1838
		goto out;

C
Chris Mason 已提交
1839
	while (1) {
1840 1841 1842
		state = rb_entry(node, struct extent_state, rb_node);
		if (state->start > search_end)
			break;
1843 1844 1845
		if (contig && found && state->start > last + 1)
			break;
		if (state->end >= cur_start && (state->state & bits) == bits) {
1846 1847 1848 1849 1850
			total_bytes += min(search_end, state->end) + 1 -
				       max(cur_start, state->start);
			if (total_bytes >= max_bytes)
				break;
			if (!found) {
1851
				*start = max(cur_start, state->start);
1852 1853
				found = 1;
			}
1854 1855 1856
			last = state->end;
		} else if (contig && found) {
			break;
1857 1858 1859 1860 1861 1862
		}
		node = rb_next(node);
		if (!node)
			break;
	}
out:
1863
	spin_unlock(&tree->lock);
1864 1865
	return total_bytes;
}
1866

C
Chris Mason 已提交
1867 1868 1869 1870
/*
 * set the private field for a given byte offset in the tree.  If there isn't
 * an extent_state there already, this does nothing.
 */
1871
static int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
1872 1873 1874 1875 1876
{
	struct rb_node *node;
	struct extent_state *state;
	int ret = 0;

1877
	spin_lock(&tree->lock);
1878 1879 1880 1881
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1882
	node = tree_search(tree, start);
1883
	if (!node) {
1884 1885 1886 1887 1888 1889 1890 1891 1892 1893
		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:
1894
	spin_unlock(&tree->lock);
1895 1896 1897 1898 1899 1900 1901 1902 1903
	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;

1904
	spin_lock(&tree->lock);
1905 1906 1907 1908
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1909
	node = tree_search(tree, start);
1910
	if (!node) {
1911 1912 1913 1914 1915 1916 1917 1918 1919 1920
		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:
1921
	spin_unlock(&tree->lock);
1922 1923 1924 1925 1926
	return ret;
}

/*
 * searches a range in the state tree for a given mask.
1927
 * If 'filled' == 1, this returns 1 only if every extent in the tree
1928 1929 1930 1931
 * 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,
1932
		   unsigned bits, int filled, struct extent_state *cached)
1933 1934 1935 1936 1937
{
	struct extent_state *state = NULL;
	struct rb_node *node;
	int bitset = 0;

1938
	spin_lock(&tree->lock);
1939
	if (cached && extent_state_in_tree(cached) && cached->start <= start &&
1940
	    cached->end > start)
1941 1942 1943
		node = &cached->rb_node;
	else
		node = tree_search(tree, start);
1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962
	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;
		}
1963 1964 1965 1966

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

1967 1968 1969 1970 1971 1972 1973 1974 1975 1976
		start = state->end + 1;
		if (start > end)
			break;
		node = rb_next(node);
		if (!node) {
			if (filled)
				bitset = 0;
			break;
		}
	}
1977
	spin_unlock(&tree->lock);
1978 1979 1980 1981 1982 1983 1984
	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
 */
1985
static void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
1986
{
M
Miao Xie 已提交
1987
	u64 start = page_offset(page);
1988
	u64 end = start + PAGE_CACHE_SIZE - 1;
1989
	if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1990 1991 1992
		SetPageUptodate(page);
}

1993
int free_io_failure(struct inode *inode, struct io_failure_record *rec)
1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
{
	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
2006 2007 2008 2009 2010
	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;
2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

	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.
2021
 * to avoid any synchronization issues, wait for the data after writing, which
2022 2023 2024 2025
 * 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.
 */
2026 2027
int repair_io_failure(struct inode *inode, u64 start, u64 length, u64 logical,
		      struct page *page, unsigned int pg_offset, int mirror_num)
2028
{
2029
	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2030 2031 2032 2033 2034
	struct bio *bio;
	struct btrfs_device *dev;
	u64 map_length = 0;
	u64 sector;
	struct btrfs_bio *bbio = NULL;
D
David Woodhouse 已提交
2035
	struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
2036 2037
	int ret;

2038
	ASSERT(!(fs_info->sb->s_flags & MS_RDONLY));
2039 2040
	BUG_ON(!mirror_num);

D
David Woodhouse 已提交
2041 2042 2043 2044
	/* we can't repair anything in raid56 yet */
	if (btrfs_is_parity_mirror(map_tree, logical, length, mirror_num))
		return 0;

2045
	bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2046 2047
	if (!bio)
		return -EIO;
2048
	bio->bi_iter.bi_size = 0;
2049 2050
	map_length = length;

2051
	ret = btrfs_map_block(fs_info, WRITE, logical,
2052 2053 2054 2055 2056 2057 2058
			      &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;
2059
	bio->bi_iter.bi_sector = sector;
2060
	dev = bbio->stripes[mirror_num-1].dev;
2061
	btrfs_put_bbio(bbio);
2062 2063 2064 2065 2066
	if (!dev || !dev->bdev || !dev->writeable) {
		bio_put(bio);
		return -EIO;
	}
	bio->bi_bdev = dev->bdev;
2067
	bio_add_page(bio, page, length, pg_offset);
2068

2069
	if (btrfsic_submit_bio_wait(WRITE_SYNC, bio)) {
2070 2071
		/* try to remap that extent elsewhere? */
		bio_put(bio);
2072
		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
2073 2074 2075
		return -EIO;
	}

2076
	printk_ratelimited_in_rcu(KERN_INFO
2077 2078 2079
				  "BTRFS: read error corrected: ino %llu off %llu (dev %s sector %llu)\n",
				  btrfs_ino(inode), start,
				  rcu_str_deref(dev->name), sector);
2080 2081 2082 2083
	bio_put(bio);
	return 0;
}

2084 2085 2086 2087 2088
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);
2089
	int ret = 0;
2090

2091 2092 2093
	if (root->fs_info->sb->s_flags & MS_RDONLY)
		return -EROFS;

2094
	for (i = 0; i < num_pages; i++) {
2095
		struct page *p = eb->pages[i];
2096 2097 2098 2099

		ret = repair_io_failure(root->fs_info->btree_inode, start,
					PAGE_CACHE_SIZE, start, p,
					start - page_offset(p), mirror_num);
2100 2101 2102 2103 2104 2105 2106 2107
		if (ret)
			break;
		start += PAGE_CACHE_SIZE;
	}

	return ret;
}

2108 2109 2110 2111
/*
 * 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
 */
2112 2113
int clean_io_failure(struct inode *inode, u64 start, struct page *page,
		     unsigned int pg_offset)
2114 2115 2116 2117
{
	u64 private;
	u64 private_failure;
	struct io_failure_record *failrec;
2118
	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142
	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;
	}
2143 2144
	if (fs_info->sb->s_flags & MS_RDONLY)
		goto out;
2145 2146 2147 2148 2149 2150 2151

	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);

2152 2153
	if (state && state->start <= failrec->start &&
	    state->end >= failrec->start + failrec->len - 1) {
2154 2155
		num_copies = btrfs_num_copies(fs_info, failrec->logical,
					      failrec->len);
2156
		if (num_copies > 1)  {
2157
			repair_io_failure(inode, start, failrec->len,
2158
					  failrec->logical, page,
2159
					  pg_offset, failrec->failed_mirror);
2160 2161 2162 2163
		}
	}

out:
2164
	free_io_failure(inode, failrec);
2165

2166
	return 0;
2167 2168
}

2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193
/*
 * 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);

2194
		failrec = (struct io_failure_record *)(unsigned long)state->private;
2195 2196 2197 2198 2199 2200 2201 2202
		free_extent_state(state);
		kfree(failrec);

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

2203 2204
int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
				struct io_failure_record **failrec_ret)
2205
{
2206
	struct io_failure_record *failrec;
2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219
	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;
2220

2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234
		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;
		}

2235
		if (em->start > start || em->start + em->len <= start) {
2236 2237 2238 2239
			free_extent_map(em);
			em = NULL;
		}
		read_unlock(&em_tree->lock);
2240
		if (!em) {
2241 2242 2243
			kfree(failrec);
			return -EIO;
		}
2244

2245 2246 2247 2248 2249 2250 2251 2252
		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);
		}
2253 2254 2255 2256

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

2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275
		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;
2276
		pr_debug("Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu, validation=%d\n",
2277 2278 2279 2280 2281 2282 2283 2284
			 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.
		 */
	}
2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295

	*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;

2296 2297
	num_copies = btrfs_num_copies(BTRFS_I(inode)->root->fs_info,
				      failrec->logical, failrec->len);
2298 2299 2300 2301 2302 2303
	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.
		 */
2304
		pr_debug("Check Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d\n",
2305
			 num_copies, failrec->this_mirror, failed_mirror);
2306
		return 0;
2307 2308 2309 2310 2311 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
	}

	/*
	 * 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++;
	}

2343
	if (failrec->this_mirror > num_copies) {
2344
		pr_debug("Check Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d\n",
2345
			 num_copies, failrec->this_mirror, failed_mirror);
2346
		return 0;
2347 2348
	}

2349 2350 2351 2352 2353 2354 2355
	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,
2356
				    bio_end_io_t *endio_func, void *data)
2357 2358 2359 2360 2361
{
	struct bio *bio;
	struct btrfs_io_bio *btrfs_failed_bio;
	struct btrfs_io_bio *btrfs_bio;

2362
	bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2363 2364 2365 2366
	if (!bio)
		return NULL;

	bio->bi_end_io = endio_func;
2367
	bio->bi_iter.bi_sector = failrec->logical >> 9;
2368
	bio->bi_bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
2369
	bio->bi_iter.bi_size = 0;
2370
	bio->bi_private = data;
2371

2372 2373 2374 2375 2376 2377 2378
	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;
2379 2380
		icsum *= csum_size;
		memcpy(btrfs_bio->csum, btrfs_failed_bio->csum + icsum,
2381 2382 2383
		       csum_size);
	}

2384 2385 2386 2387 2388 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
	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),
2428 2429
				      (int)phy_offset, failed_bio->bi_end_io,
				      NULL);
2430 2431 2432 2433
	if (!bio) {
		free_io_failure(inode, failrec);
		return -EIO;
	}
2434

2435 2436
	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);
2437

2438 2439 2440
	ret = tree->ops->submit_bio_hook(inode, read_mode, bio,
					 failrec->this_mirror,
					 failrec->bio_flags, 0);
2441
	if (ret) {
2442
		free_io_failure(inode, failrec);
2443 2444 2445
		bio_put(bio);
	}

2446
	return ret;
2447 2448
}

2449 2450
/* lots and lots of room for performance fixes in the end_bio funcs */

2451 2452 2453 2454
int end_extent_writepage(struct page *page, int err, u64 start, u64 end)
{
	int uptodate = (err == 0);
	struct extent_io_tree *tree;
2455
	int ret = 0;
2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468

	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);
2469 2470
		ret = ret < 0 ? ret : -EIO;
		mapping_set_error(page->mapping, ret);
2471 2472 2473 2474
	}
	return 0;
}

2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485
/*
 * 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.
 */
static void end_bio_extent_writepage(struct bio *bio, int err)
{
2486
	struct bio_vec *bvec;
2487 2488
	u64 start;
	u64 end;
2489
	int i;
2490

2491
	bio_for_each_segment_all(bvec, bio, i) {
2492
		struct page *page = bvec->bv_page;
2493

2494 2495 2496 2497 2498
		/* 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.  */
2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509
		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);
		}
2510

2511 2512
		start = page_offset(page);
		end = start + bvec->bv_offset + bvec->bv_len - 1;
2513

2514 2515
		if (end_extent_writepage(page, err, start, end))
			continue;
2516

2517
		end_page_writeback(page);
2518
	}
2519

2520 2521 2522
	bio_put(bio);
}

2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534
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);
}

2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547
/*
 * 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.
 */
static void end_bio_extent_readpage(struct bio *bio, int err)
{
2548
	struct bio_vec *bvec;
2549
	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
2550
	struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
2551
	struct extent_io_tree *tree;
2552
	u64 offset = 0;
2553 2554
	u64 start;
	u64 end;
2555
	u64 len;
2556 2557
	u64 extent_start = 0;
	u64 extent_len = 0;
2558
	int mirror;
2559
	int ret;
2560
	int i;
2561

2562 2563 2564
	if (err)
		uptodate = 0;

2565
	bio_for_each_segment_all(bvec, bio, i) {
2566
		struct page *page = bvec->bv_page;
2567
		struct inode *inode = page->mapping->host;
2568

2569
		pr_debug("end_bio_extent_readpage: bi_sector=%llu, err=%d, "
2570
			 "mirror=%u\n", (u64)bio->bi_iter.bi_sector, err,
2571
			 io_bio->mirror_num);
2572
		tree = &BTRFS_I(inode)->io_tree;
2573

2574 2575 2576 2577 2578
		/* 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.  */
2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589
		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);
		}
2590

2591 2592
		start = page_offset(page);
		end = start + bvec->bv_offset + bvec->bv_len - 1;
2593
		len = bvec->bv_len;
2594

2595
		mirror = io_bio->mirror_num;
2596 2597
		if (likely(uptodate && tree->ops &&
			   tree->ops->readpage_end_io_hook)) {
2598 2599 2600
			ret = tree->ops->readpage_end_io_hook(io_bio, offset,
							      page, start, end,
							      mirror);
2601
			if (ret)
2602
				uptodate = 0;
2603
			else
2604
				clean_io_failure(inode, start, page, 0);
2605
		}
2606

2607 2608 2609 2610
		if (likely(uptodate))
			goto readpage_ok;

		if (tree->ops && tree->ops->readpage_io_failed_hook) {
2611
			ret = tree->ops->readpage_io_failed_hook(page, mirror);
2612 2613 2614
			if (!ret && !err &&
			    test_bit(BIO_UPTODATE, &bio->bi_flags))
				uptodate = 1;
2615
		} else {
2616 2617 2618 2619 2620 2621 2622 2623 2624 2625
			/*
			 * 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.
			 */
2626 2627
			ret = bio_readpage_error(bio, offset, page, start, end,
						 mirror);
2628
			if (ret == 0) {
2629 2630
				uptodate =
					test_bit(BIO_UPTODATE, &bio->bi_flags);
2631 2632
				if (err)
					uptodate = 0;
2633
				offset += len;
2634 2635 2636
				continue;
			}
		}
2637
readpage_ok:
2638
		if (likely(uptodate)) {
2639 2640
			loff_t i_size = i_size_read(inode);
			pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
2641
			unsigned off;
2642 2643

			/* Zero out the end if this page straddles i_size */
2644 2645 2646
			off = i_size & (PAGE_CACHE_SIZE-1);
			if (page->index == end_index && off)
				zero_user_segment(page, off, PAGE_CACHE_SIZE);
2647
			SetPageUptodate(page);
2648
		} else {
2649 2650
			ClearPageUptodate(page);
			SetPageError(page);
2651
		}
2652
		unlock_page(page);
2653
		offset += len;
2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675

		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;
		}
2676
	}
2677

2678 2679 2680
	if (extent_len)
		endio_readpage_release_extent(tree, extent_start, extent_len,
					      uptodate);
2681 2682
	if (io_bio->end_io)
		io_bio->end_io(io_bio, err);
2683 2684 2685
	bio_put(bio);
}

2686 2687 2688 2689
/*
 * 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
 */
2690 2691 2692
struct bio *
btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
		gfp_t gfp_flags)
2693
{
2694
	struct btrfs_io_bio *btrfs_bio;
2695 2696
	struct bio *bio;

2697
	bio = bio_alloc_bioset(gfp_flags, nr_vecs, btrfs_bioset);
2698 2699

	if (bio == NULL && (current->flags & PF_MEMALLOC)) {
2700 2701 2702 2703
		while (!bio && (nr_vecs /= 2)) {
			bio = bio_alloc_bioset(gfp_flags,
					       nr_vecs, btrfs_bioset);
		}
2704 2705 2706 2707
	}

	if (bio) {
		bio->bi_bdev = bdev;
2708
		bio->bi_iter.bi_sector = first_sector;
2709 2710 2711 2712
		btrfs_bio = btrfs_io_bio(bio);
		btrfs_bio->csum = NULL;
		btrfs_bio->csum_allocated = NULL;
		btrfs_bio->end_io = NULL;
2713 2714 2715 2716
	}
	return bio;
}

2717 2718
struct bio *btrfs_bio_clone(struct bio *bio, gfp_t gfp_mask)
{
2719 2720
	struct btrfs_io_bio *btrfs_bio;
	struct bio *new;
2721

2722 2723 2724 2725 2726 2727 2728 2729 2730
	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;
}
2731 2732 2733 2734

/* this also allocates from the btrfs_bioset */
struct bio *btrfs_io_bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
{
2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745
	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;
2746 2747 2748
}


2749 2750
static int __must_check submit_one_bio(int rw, struct bio *bio,
				       int mirror_num, unsigned long bio_flags)
2751 2752
{
	int ret = 0;
2753 2754 2755 2756 2757
	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
2758
	start = page_offset(page) + bvec->bv_offset;
2759

2760
	bio->bi_private = NULL;
2761 2762 2763

	bio_get(bio);

2764
	if (tree->ops && tree->ops->submit_bio_hook)
2765
		ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
2766
					   mirror_num, bio_flags, start);
2767
	else
2768
		btrfsic_submit_bio(rw, bio);
2769

2770 2771 2772 2773 2774 2775
	if (bio_flagged(bio, BIO_EOPNOTSUPP))
		ret = -EOPNOTSUPP;
	bio_put(bio);
	return ret;
}

2776
static int merge_bio(int rw, struct extent_io_tree *tree, struct page *page,
2777 2778 2779 2780 2781
		     unsigned long offset, size_t size, struct bio *bio,
		     unsigned long bio_flags)
{
	int ret = 0;
	if (tree->ops && tree->ops->merge_bio_hook)
2782
		ret = tree->ops->merge_bio_hook(rw, page, offset, size, bio,
2783 2784 2785 2786 2787 2788
						bio_flags);
	BUG_ON(ret < 0);
	return ret;

}

2789 2790 2791 2792 2793 2794
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,
2795
			      bio_end_io_t end_io_func,
C
Chris Mason 已提交
2796 2797 2798
			      int mirror_num,
			      unsigned long prev_bio_flags,
			      unsigned long bio_flags)
2799 2800 2801 2802
{
	int ret = 0;
	struct bio *bio;
	int nr;
C
Chris Mason 已提交
2803 2804 2805
	int contig = 0;
	int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
	int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
2806
	size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
2807 2808 2809

	if (bio_ret && *bio_ret) {
		bio = *bio_ret;
C
Chris Mason 已提交
2810
		if (old_compressed)
2811
			contig = bio->bi_iter.bi_sector == sector;
C
Chris Mason 已提交
2812
		else
K
Kent Overstreet 已提交
2813
			contig = bio_end_sector(bio) == sector;
C
Chris Mason 已提交
2814 2815

		if (prev_bio_flags != bio_flags || !contig ||
2816
		    merge_bio(rw, tree, page, offset, page_size, bio, bio_flags) ||
C
Chris Mason 已提交
2817 2818 2819
		    bio_add_page(bio, page, page_size, offset) < page_size) {
			ret = submit_one_bio(rw, bio, mirror_num,
					     prev_bio_flags);
2820 2821
			if (ret < 0) {
				*bio_ret = NULL;
2822
				return ret;
2823
			}
2824 2825 2826 2827 2828
			bio = NULL;
		} else {
			return 0;
		}
	}
C
Chris Mason 已提交
2829 2830 2831 2832 2833
	if (this_compressed)
		nr = BIO_MAX_PAGES;
	else
		nr = bio_get_nr_vecs(bdev);

2834
	bio = btrfs_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
2835 2836
	if (!bio)
		return -ENOMEM;
2837

C
Chris Mason 已提交
2838
	bio_add_page(bio, page, page_size, offset);
2839 2840
	bio->bi_end_io = end_io_func;
	bio->bi_private = tree;
2841

C
Chris Mason 已提交
2842
	if (bio_ret)
2843
		*bio_ret = bio;
C
Chris Mason 已提交
2844
	else
C
Chris Mason 已提交
2845
		ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
2846 2847 2848 2849

	return ret;
}

2850 2851
static void attach_extent_buffer_page(struct extent_buffer *eb,
				      struct page *page)
2852 2853 2854 2855
{
	if (!PagePrivate(page)) {
		SetPagePrivate(page);
		page_cache_get(page);
J
Josef Bacik 已提交
2856 2857 2858
		set_page_private(page, (unsigned long)eb);
	} else {
		WARN_ON(page->private != (unsigned long)eb);
2859 2860 2861
	}
}

J
Josef Bacik 已提交
2862
void set_page_extent_mapped(struct page *page)
2863
{
J
Josef Bacik 已提交
2864 2865 2866 2867 2868
	if (!PagePrivate(page)) {
		SetPagePrivate(page);
		page_cache_get(page);
		set_page_private(page, EXTENT_PAGE_PRIVATE);
	}
2869 2870
}

2871 2872 2873 2874 2875 2876 2877 2878 2879
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;
2880
		if (extent_map_in_tree(em) && start >= em->start &&
2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897
		    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;
}
2898 2899 2900 2901
/*
 * 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)
2902
 * XXX JDM: This needs looking at to ensure proper page locking
2903
 */
2904 2905 2906
static int __do_readpage(struct extent_io_tree *tree,
			 struct page *page,
			 get_extent_t *get_extent,
2907
			 struct extent_map **em_cached,
2908 2909
			 struct bio **bio, int mirror_num,
			 unsigned long *bio_flags, int rw)
2910 2911
{
	struct inode *inode = page->mapping->host;
M
Miao Xie 已提交
2912
	u64 start = page_offset(page);
2913 2914 2915 2916 2917 2918 2919 2920 2921 2922 2923 2924
	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;
2925
	int parent_locked = *bio_flags & EXTENT_BIO_PARENT_LOCKED;
2926
	size_t pg_offset = 0;
2927
	size_t iosize;
C
Chris Mason 已提交
2928
	size_t disk_io_size;
2929
	size_t blocksize = inode->i_sb->s_blocksize;
2930
	unsigned long this_bio_flag = *bio_flags & EXTENT_BIO_PARENT_LOCKED;
2931 2932 2933

	set_page_extent_mapped(page);

2934
	end = page_end;
D
Dan Magenheimer 已提交
2935 2936 2937
	if (!PageUptodate(page)) {
		if (cleancache_get_page(page) == 0) {
			BUG_ON(blocksize != PAGE_SIZE);
2938
			unlock_extent(tree, start, end);
D
Dan Magenheimer 已提交
2939 2940 2941 2942
			goto out;
		}
	}

C
Chris Mason 已提交
2943 2944 2945 2946 2947 2948
	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;
2949
			userpage = kmap_atomic(page);
C
Chris Mason 已提交
2950 2951
			memset(userpage + zero_offset, 0, iosize);
			flush_dcache_page(page);
2952
			kunmap_atomic(userpage);
C
Chris Mason 已提交
2953 2954
		}
	}
2955
	while (cur <= end) {
2956 2957
		unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;

2958 2959
		if (cur >= last_byte) {
			char *userpage;
2960 2961
			struct extent_state *cached = NULL;

2962
			iosize = PAGE_CACHE_SIZE - pg_offset;
2963
			userpage = kmap_atomic(page);
2964
			memset(userpage + pg_offset, 0, iosize);
2965
			flush_dcache_page(page);
2966
			kunmap_atomic(userpage);
2967
			set_extent_uptodate(tree, cur, cur + iosize - 1,
2968
					    &cached, GFP_NOFS);
2969 2970 2971 2972
			if (!parent_locked)
				unlock_extent_cached(tree, cur,
						     cur + iosize - 1,
						     &cached, GFP_NOFS);
2973 2974
			break;
		}
2975 2976
		em = __get_extent_map(inode, page, pg_offset, cur,
				      end - cur + 1, get_extent, em_cached);
2977
		if (IS_ERR_OR_NULL(em)) {
2978
			SetPageError(page);
2979 2980
			if (!parent_locked)
				unlock_extent(tree, cur, end);
2981 2982 2983 2984 2985 2986
			break;
		}
		extent_offset = cur - em->start;
		BUG_ON(extent_map_end(em) <= cur);
		BUG_ON(end < cur);

2987
		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2988
			this_bio_flag |= EXTENT_BIO_COMPRESSED;
2989 2990 2991
			extent_set_compress_type(&this_bio_flag,
						 em->compress_type);
		}
C
Chris Mason 已提交
2992

2993 2994
		iosize = min(extent_map_end(em) - cur, end - cur + 1);
		cur_end = min(extent_map_end(em) - 1, end);
2995
		iosize = ALIGN(iosize, blocksize);
C
Chris Mason 已提交
2996 2997 2998 2999 3000 3001 3002
		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;
		}
3003 3004
		bdev = em->bdev;
		block_start = em->block_start;
Y
Yan Zheng 已提交
3005 3006
		if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
			block_start = EXTENT_MAP_HOLE;
3007 3008 3009 3010 3011 3012
		free_extent_map(em);
		em = NULL;

		/* we've found a hole, just zero and go on */
		if (block_start == EXTENT_MAP_HOLE) {
			char *userpage;
3013 3014
			struct extent_state *cached = NULL;

3015
			userpage = kmap_atomic(page);
3016
			memset(userpage + pg_offset, 0, iosize);
3017
			flush_dcache_page(page);
3018
			kunmap_atomic(userpage);
3019 3020

			set_extent_uptodate(tree, cur, cur + iosize - 1,
3021 3022 3023
					    &cached, GFP_NOFS);
			unlock_extent_cached(tree, cur, cur + iosize - 1,
			                     &cached, GFP_NOFS);
3024
			cur = cur + iosize;
3025
			pg_offset += iosize;
3026 3027 3028
			continue;
		}
		/* the get_extent function already copied into the page */
3029 3030
		if (test_range_bit(tree, cur, cur_end,
				   EXTENT_UPTODATE, 1, NULL)) {
3031
			check_page_uptodate(tree, page);
3032 3033
			if (!parent_locked)
				unlock_extent(tree, cur, cur + iosize - 1);
3034
			cur = cur + iosize;
3035
			pg_offset += iosize;
3036 3037
			continue;
		}
3038 3039 3040 3041 3042
		/* we have an inline extent but it didn't get marked up
		 * to date.  Error out
		 */
		if (block_start == EXTENT_MAP_INLINE) {
			SetPageError(page);
3043 3044
			if (!parent_locked)
				unlock_extent(tree, cur, cur + iosize - 1);
3045
			cur = cur + iosize;
3046
			pg_offset += iosize;
3047 3048
			continue;
		}
3049

3050
		pnr -= page->index;
3051
		ret = submit_extent_page(rw, tree, page,
3052
					 sector, disk_io_size, pg_offset,
3053
					 bdev, bio, pnr,
C
Chris Mason 已提交
3054 3055 3056
					 end_bio_extent_readpage, mirror_num,
					 *bio_flags,
					 this_bio_flag);
3057 3058 3059 3060
		if (!ret) {
			nr++;
			*bio_flags = this_bio_flag;
		} else {
3061
			SetPageError(page);
3062 3063
			if (!parent_locked)
				unlock_extent(tree, cur, cur + iosize - 1);
3064
		}
3065
		cur = cur + iosize;
3066
		pg_offset += iosize;
3067
	}
D
Dan Magenheimer 已提交
3068
out:
3069 3070 3071 3072 3073 3074 3075 3076
	if (!nr) {
		if (!PageError(page))
			SetPageUptodate(page);
		unlock_page(page);
	}
	return 0;
}

3077 3078 3079 3080
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,
3081
					     struct extent_map **em_cached,
3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101
					     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++) {
3102 3103
		__do_readpage(tree, pages[index], get_extent, em_cached, bio,
			      mirror_num, bio_flags, rw);
3104 3105 3106 3107 3108 3109 3110
		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,
3111
			       struct extent_map **em_cached,
3112 3113 3114
			       struct bio **bio, int mirror_num,
			       unsigned long *bio_flags, int rw)
{
3115
	u64 start = 0;
3116 3117 3118
	u64 end = 0;
	u64 page_start;
	int index;
3119
	int first_index = 0;
3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131

	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,
3132 3133 3134
						  end, get_extent, em_cached,
						  bio, mirror_num, bio_flags,
						  rw);
3135 3136 3137 3138 3139 3140 3141 3142 3143
			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,
3144
					  end, get_extent, em_cached, bio,
3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169
					  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);
	}

3170 3171
	ret = __do_readpage(tree, page, get_extent, NULL, bio, mirror_num,
			    bio_flags, rw);
3172 3173 3174
	return ret;
}

3175
int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
3176
			    get_extent_t *get_extent, int mirror_num)
3177 3178
{
	struct bio *bio = NULL;
C
Chris Mason 已提交
3179
	unsigned long bio_flags = 0;
3180 3181
	int ret;

3182
	ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
3183
				      &bio_flags, READ);
3184
	if (bio)
3185
		ret = submit_one_bio(READ, bio, mirror_num, bio_flags);
3186 3187 3188
	return ret;
}

3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202
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;
}

3203 3204 3205 3206 3207 3208 3209 3210 3211 3212
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;
}

3213
/*
3214 3215 3216 3217 3218 3219 3220 3221
 * 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)
3222
 */
3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244
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,
3245
					       BTRFS_MAX_EXTENT_SIZE);
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 3315 3316 3317 3318
		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)
3319 3320
{
	struct extent_io_tree *tree = epd->tree;
M
Miao Xie 已提交
3321
	u64 start = page_offset(page);
3322 3323 3324 3325 3326 3327 3328
	u64 page_end = start + PAGE_CACHE_SIZE - 1;
	u64 end;
	u64 cur = start;
	u64 extent_offset;
	u64 block_start;
	u64 iosize;
	sector_t sector;
3329
	struct extent_state *cached_state = NULL;
3330 3331
	struct extent_map *em;
	struct block_device *bdev;
3332
	size_t pg_offset = 0;
3333
	size_t blocksize;
3334 3335 3336
	int ret = 0;
	int nr = 0;
	bool compressed;
C
Chris Mason 已提交
3337

3338
	if (tree->ops && tree->ops->writepage_start_hook) {
C
Chris Mason 已提交
3339 3340
		ret = tree->ops->writepage_start_hook(page, start,
						      page_end);
3341 3342 3343 3344 3345 3346
		if (ret) {
			/* Fixup worker will requeue */
			if (ret == -EBUSY)
				wbc->pages_skipped++;
			else
				redirty_page_for_writepage(wbc, page);
3347

3348
			update_nr_written(page, wbc, nr_written);
3349
			unlock_page(page);
3350
			ret = 1;
3351
			goto done_unlocked;
3352 3353 3354
		}
	}

3355 3356 3357 3358 3359
	/*
	 * 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);
3360

3361
	end = page_end;
3362
	if (i_size <= start) {
3363 3364 3365
		if (tree->ops && tree->ops->writepage_end_io_hook)
			tree->ops->writepage_end_io_hook(page, start,
							 page_end, NULL, 1);
3366 3367 3368 3369 3370 3371
		goto done;
	}

	blocksize = inode->i_sb->s_blocksize;

	while (cur <= end) {
3372 3373
		u64 em_end;
		if (cur >= i_size) {
3374 3375 3376
			if (tree->ops && tree->ops->writepage_end_io_hook)
				tree->ops->writepage_end_io_hook(page, cur,
							 page_end, NULL, 1);
3377 3378
			break;
		}
3379
		em = epd->get_extent(inode, page, pg_offset, cur,
3380
				     end - cur + 1, 1);
3381
		if (IS_ERR_OR_NULL(em)) {
3382
			SetPageError(page);
3383
			ret = PTR_ERR_OR_ZERO(em);
3384 3385 3386 3387
			break;
		}

		extent_offset = cur - em->start;
3388 3389
		em_end = extent_map_end(em);
		BUG_ON(em_end <= cur);
3390
		BUG_ON(end < cur);
3391
		iosize = min(em_end - cur, end - cur + 1);
3392
		iosize = ALIGN(iosize, blocksize);
3393 3394 3395
		sector = (em->block_start + extent_offset) >> 9;
		bdev = em->bdev;
		block_start = em->block_start;
C
Chris Mason 已提交
3396
		compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
3397 3398 3399
		free_extent_map(em);
		em = NULL;

C
Chris Mason 已提交
3400 3401 3402 3403 3404
		/*
		 * compressed and inline extents are written through other
		 * paths in the FS
		 */
		if (compressed || block_start == EXTENT_MAP_HOLE ||
3405
		    block_start == EXTENT_MAP_INLINE) {
C
Chris Mason 已提交
3406 3407 3408 3409 3410 3411
			/*
			 * end_io notification does not happen here for
			 * compressed extents
			 */
			if (!compressed && tree->ops &&
			    tree->ops->writepage_end_io_hook)
3412 3413 3414
				tree->ops->writepage_end_io_hook(page, cur,
							 cur + iosize - 1,
							 NULL, 1);
C
Chris Mason 已提交
3415 3416 3417 3418 3419 3420 3421 3422 3423
			else if (compressed) {
				/* we don't want to end_page_writeback on
				 * a compressed extent.  this happens
				 * elsewhere
				 */
				nr++;
			}

			cur += iosize;
3424
			pg_offset += iosize;
3425 3426
			continue;
		}
C
Chris Mason 已提交
3427

3428 3429 3430 3431 3432 3433
		if (tree->ops && tree->ops->writepage_io_hook) {
			ret = tree->ops->writepage_io_hook(page, cur,
						cur + iosize - 1);
		} else {
			ret = 0;
		}
3434
		if (ret) {
3435
			SetPageError(page);
3436
		} else {
3437
			unsigned long max_nr = (i_size >> PAGE_CACHE_SHIFT) + 1;
3438

3439 3440
			set_range_writeback(tree, cur, cur + iosize - 1);
			if (!PageWriteback(page)) {
3441 3442
				btrfs_err(BTRFS_I(inode)->root->fs_info,
					   "page %lu not writeback, cur %llu end %llu",
3443
				       page->index, cur, end);
3444 3445
			}

3446 3447 3448
			ret = submit_extent_page(write_flags, tree, page,
						 sector, iosize, pg_offset,
						 bdev, &epd->bio, max_nr,
C
Chris Mason 已提交
3449 3450
						 end_bio_extent_writepage,
						 0, 0, 0);
3451 3452 3453 3454
			if (ret)
				SetPageError(page);
		}
		cur = cur + iosize;
3455
		pg_offset += iosize;
3456 3457
		nr++;
	}
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 3529 3530 3531 3532
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;

3533 3534 3535 3536 3537 3538
done:
	if (nr == 0) {
		/* make sure the mapping tag for page dirty gets cleared */
		set_page_writeback(page);
		end_page_writeback(page);
	}
3539 3540 3541 3542
	if (PageError(page)) {
		ret = ret < 0 ? ret : -EIO;
		end_extent_writepage(page, ret, start, page_end);
	}
3543
	unlock_page(page);
3544
	return ret;
3545

3546
done_unlocked:
3547 3548 3549
	return 0;
}

3550
void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
3551
{
3552 3553
	wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
		       TASK_UNINTERRUPTIBLE);
3554 3555
}

3556 3557 3558 3559
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)
3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578
{
	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
3579 3580 3581 3582 3583
		while (1) {
			wait_on_extent_buffer_writeback(eb);
			btrfs_tree_lock(eb);
			if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
				break;
3584 3585 3586 3587
			btrfs_tree_unlock(eb);
		}
	}

3588 3589 3590 3591 3592 3593
	/*
	 * 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);
3594 3595
	if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
		set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3596
		spin_unlock(&eb->refs_lock);
3597
		btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3598 3599 3600
		__percpu_counter_add(&fs_info->dirty_metadata_bytes,
				     -eb->len,
				     fs_info->dirty_metadata_batch);
3601
		ret = 1;
3602 3603
	} else {
		spin_unlock(&eb->refs_lock);
3604 3605 3606 3607 3608 3609 3610 3611 3612
	}

	btrfs_tree_unlock(eb);

	if (!ret)
		return ret;

	num_pages = num_extent_pages(eb->start, eb->len);
	for (i = 0; i < num_pages; i++) {
3613
		struct page *p = eb->pages[i];
3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 3624 3625 3626 3627 3628 3629

		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);
3630
	smp_mb__after_atomic();
3631 3632 3633
	wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
}

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 3692 3693 3694 3695
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 */
	}
}

3696 3697
static void end_bio_extent_buffer_writepage(struct bio *bio, int err)
{
3698
	struct bio_vec *bvec;
3699
	struct extent_buffer *eb;
3700
	int i, done;
3701

3702
	bio_for_each_segment_all(bvec, bio, i) {
3703 3704 3705 3706 3707 3708
		struct page *page = bvec->bv_page;

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

3709
		if (err || test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) {
3710
			ClearPageUptodate(page);
3711
			set_btree_ioerr(page);
3712 3713 3714 3715 3716 3717 3718 3719
		}

		end_page_writeback(page);

		if (!done)
			continue;

		end_extent_buffer_writeback(eb);
3720
	}
3721 3722 3723 3724

	bio_put(bio);
}

3725
static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
3726 3727 3728 3729 3730
			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;
3731
	struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
3732 3733
	u64 offset = eb->start;
	unsigned long i, num_pages;
3734
	unsigned long bio_flags = 0;
3735
	int rw = (epd->sync_io ? WRITE_SYNC : WRITE) | REQ_META;
3736
	int ret = 0;
3737

3738
	clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
3739 3740
	num_pages = num_extent_pages(eb->start, eb->len);
	atomic_set(&eb->io_pages, num_pages);
3741 3742 3743
	if (btrfs_header_owner(eb) == BTRFS_TREE_LOG_OBJECTID)
		bio_flags = EXTENT_BIO_TREE_LOG;

3744
	for (i = 0; i < num_pages; i++) {
3745
		struct page *p = eb->pages[i];
3746 3747 3748

		clear_page_dirty_for_io(p);
		set_page_writeback(p);
3749
		ret = submit_extent_page(rw, tree, p, offset >> 9,
3750 3751
					 PAGE_CACHE_SIZE, 0, bdev, &epd->bio,
					 -1, end_bio_extent_buffer_writepage,
3752 3753
					 0, epd->bio_flags, bio_flags);
		epd->bio_flags = bio_flags;
3754
		if (ret) {
3755
			set_btree_ioerr(p);
3756
			end_page_writeback(p);
3757 3758 3759 3760 3761 3762 3763 3764 3765 3766 3767 3768
			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++) {
3769
			struct page *p = eb->pages[i];
3770
			clear_page_dirty_for_io(p);
3771 3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787 3788
			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,
3789
		.bio_flags = 0,
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 3831 3832 3833
	};
	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;
			}

3834 3835 3836 3837 3838 3839
			spin_lock(&mapping->private_lock);
			if (!PagePrivate(page)) {
				spin_unlock(&mapping->private_lock);
				continue;
			}

3840
			eb = (struct extent_buffer *)page->private;
3841 3842 3843 3844 3845 3846

			/*
			 * 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.
			 */
3847
			if (WARN_ON(!eb)) {
3848
				spin_unlock(&mapping->private_lock);
3849 3850 3851
				continue;
			}

3852 3853
			if (eb == prev_eb) {
				spin_unlock(&mapping->private_lock);
3854
				continue;
3855
			}
3856

3857 3858 3859
			ret = atomic_inc_not_zero(&eb->refs);
			spin_unlock(&mapping->private_lock);
			if (!ret)
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 3897 3898 3899
				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;
}

3900
/**
C
Chris Mason 已提交
3901
 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912 3913 3914
 * @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.
 */
3915
static int extent_write_cache_pages(struct extent_io_tree *tree,
C
Chris Mason 已提交
3916 3917
			     struct address_space *mapping,
			     struct writeback_control *wbc,
C
Chris Mason 已提交
3918 3919
			     writepage_t writepage, void *data,
			     void (*flush_fn)(void *))
3920
{
3921
	struct inode *inode = mapping->host;
3922 3923
	int ret = 0;
	int done = 0;
3924
	int err = 0;
3925
	int nr_to_write_done = 0;
3926 3927 3928 3929 3930
	struct pagevec pvec;
	int nr_pages;
	pgoff_t index;
	pgoff_t end;		/* Inclusive */
	int scanned = 0;
3931
	int tag;
3932

3933 3934 3935 3936 3937 3938 3939 3940 3941 3942 3943 3944
	/*
	 * 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;

3945 3946 3947 3948 3949 3950 3951 3952 3953
	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;
	}
3954 3955 3956 3957
	if (wbc->sync_mode == WB_SYNC_ALL)
		tag = PAGECACHE_TAG_TOWRITE;
	else
		tag = PAGECACHE_TAG_DIRTY;
3958
retry:
3959 3960
	if (wbc->sync_mode == WB_SYNC_ALL)
		tag_pages_for_writeback(mapping, index, end);
3961
	while (!done && !nr_to_write_done && (index <= end) &&
3962 3963
	       (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
			min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
3964 3965 3966 3967 3968 3969 3970 3971 3972 3973 3974 3975 3976
		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
			 */
3977 3978 3979
			if (!trylock_page(page)) {
				flush_fn(data);
				lock_page(page);
3980
			}
3981 3982 3983 3984 3985 3986 3987 3988 3989 3990 3991 3992

			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
3993
			if (wbc->sync_mode != WB_SYNC_NONE) {
3994 3995
				if (PageWriteback(page))
					flush_fn(data);
3996
				wait_on_page_writeback(page);
C
Chris Mason 已提交
3997
			}
3998 3999 4000 4001 4002 4003 4004 4005 4006 4007 4008 4009 4010

			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;
			}
4011 4012
			if (!err && ret < 0)
				err = ret;
4013 4014 4015 4016 4017 4018 4019

			/*
			 * 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;
4020 4021 4022 4023
		}
		pagevec_release(&pvec);
		cond_resched();
	}
4024
	if (!scanned && !done && !err) {
4025 4026 4027 4028 4029 4030 4031 4032
		/*
		 * 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;
	}
4033
	btrfs_add_delayed_iput(inode);
4034
	return err;
4035 4036
}

4037
static void flush_epd_write_bio(struct extent_page_data *epd)
C
Chris Mason 已提交
4038 4039
{
	if (epd->bio) {
4040 4041 4042
		int rw = WRITE;
		int ret;

4043
		if (epd->sync_io)
4044 4045
			rw = WRITE_SYNC;

4046
		ret = submit_one_bio(rw, epd->bio, 0, epd->bio_flags);
4047
		BUG_ON(ret < 0); /* -ENOMEM */
C
Chris Mason 已提交
4048 4049 4050 4051
		epd->bio = NULL;
	}
}

4052 4053 4054 4055 4056 4057
static noinline void flush_write_bio(void *data)
{
	struct extent_page_data *epd = data;
	flush_epd_write_bio(epd);
}

4058 4059 4060 4061 4062 4063 4064 4065 4066
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,
4067
		.extent_locked = 0,
4068
		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
4069
		.bio_flags = 0,
4070 4071 4072 4073
	};

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

4074
	flush_epd_write_bio(&epd);
4075 4076 4077
	return ret;
}

4078 4079 4080 4081 4082 4083 4084 4085 4086 4087 4088 4089 4090 4091 4092
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,
4093
		.sync_io = mode == WB_SYNC_ALL,
4094
		.bio_flags = 0,
4095 4096 4097 4098 4099 4100 4101 4102
	};
	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
4103
	while (start <= end) {
4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117
		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;
	}

4118
	flush_epd_write_bio(&epd);
4119 4120
	return ret;
}
4121 4122 4123 4124 4125 4126 4127 4128 4129 4130 4131

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,
4132
		.extent_locked = 0,
4133
		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
4134
		.bio_flags = 0,
4135 4136
	};

C
Chris Mason 已提交
4137
	ret = extent_write_cache_pages(tree, mapping, wbc,
C
Chris Mason 已提交
4138 4139
				       __extent_writepage, &epd,
				       flush_write_bio);
4140
	flush_epd_write_bio(&epd);
4141 4142 4143 4144 4145 4146 4147 4148 4149 4150
	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
4151
	unsigned long bio_flags = 0;
L
Liu Bo 已提交
4152 4153
	struct page *pagepool[16];
	struct page *page;
4154
	struct extent_map *em_cached = NULL;
L
Liu Bo 已提交
4155
	int nr = 0;
4156 4157

	for (page_idx = 0; page_idx < nr_pages; page_idx++) {
L
Liu Bo 已提交
4158
		page = list_entry(pages->prev, struct page, lru);
4159 4160 4161

		prefetchw(&page->flags);
		list_del(&page->lru);
L
Liu Bo 已提交
4162
		if (add_to_page_cache_lru(page, mapping,
4163
					page->index, GFP_NOFS)) {
L
Liu Bo 已提交
4164 4165
			page_cache_release(page);
			continue;
4166
		}
L
Liu Bo 已提交
4167 4168 4169 4170

		pagepool[nr++] = page;
		if (nr < ARRAY_SIZE(pagepool))
			continue;
4171
		__extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
4172
				   &bio, 0, &bio_flags, READ);
L
Liu Bo 已提交
4173
		nr = 0;
4174
	}
4175
	if (nr)
4176
		__extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
4177
				   &bio, 0, &bio_flags, READ);
L
Liu Bo 已提交
4178

4179 4180 4181
	if (em_cached)
		free_extent_map(em_cached);

4182 4183
	BUG_ON(!list_empty(pages));
	if (bio)
4184
		return submit_one_bio(READ, bio, 0, bio_flags);
4185 4186 4187 4188 4189 4190 4191 4192 4193 4194 4195
	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)
{
4196
	struct extent_state *cached_state = NULL;
M
Miao Xie 已提交
4197
	u64 start = page_offset(page);
4198 4199 4200
	u64 end = start + PAGE_CACHE_SIZE - 1;
	size_t blocksize = page->mapping->host->i_sb->s_blocksize;

4201
	start += ALIGN(offset, blocksize);
4202 4203 4204
	if (start > end)
		return 0;

4205
	lock_extent_bits(tree, start, end, 0, &cached_state);
4206
	wait_on_page_writeback(page);
4207
	clear_extent_bit(tree, start, end,
4208 4209
			 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
			 EXTENT_DO_ACCOUNTING,
4210
			 1, 1, &cached_state, GFP_NOFS);
4211 4212 4213
	return 0;
}

4214 4215 4216 4217 4218
/*
 * 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.
 */
4219 4220 4221
static int try_release_extent_state(struct extent_map_tree *map,
				    struct extent_io_tree *tree,
				    struct page *page, gfp_t mask)
4222
{
M
Miao Xie 已提交
4223
	u64 start = page_offset(page);
4224 4225 4226
	u64 end = start + PAGE_CACHE_SIZE - 1;
	int ret = 1;

4227
	if (test_range_bit(tree, start, end,
4228
			   EXTENT_IOBITS, 0, NULL))
4229 4230 4231 4232
		ret = 0;
	else {
		if ((mask & GFP_NOFS) == GFP_NOFS)
			mask = GFP_NOFS;
4233 4234 4235 4236
		/*
		 * at this point we can safely clear everything except the
		 * locked bit and the nodatasum bit
		 */
4237
		ret = clear_extent_bit(tree, start, end,
4238 4239
				 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
				 0, 0, NULL, mask);
4240 4241 4242 4243 4244 4245 4246 4247

		/* if clear_extent_bit failed for enomem reasons,
		 * we can't allow the release to continue.
		 */
		if (ret < 0)
			ret = 0;
		else
			ret = 1;
4248 4249 4250 4251
	}
	return ret;
}

4252 4253 4254 4255 4256 4257
/*
 * 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,
4258 4259
			       struct extent_io_tree *tree, struct page *page,
			       gfp_t mask)
4260 4261
{
	struct extent_map *em;
M
Miao Xie 已提交
4262
	u64 start = page_offset(page);
4263
	u64 end = start + PAGE_CACHE_SIZE - 1;
4264

4265 4266
	if ((mask & __GFP_WAIT) &&
	    page->mapping->host->i_size > 16 * 1024 * 1024) {
4267
		u64 len;
4268
		while (start <= end) {
4269
			len = end - start + 1;
4270
			write_lock(&map->lock);
4271
			em = lookup_extent_mapping(map, start, len);
4272
			if (!em) {
4273
				write_unlock(&map->lock);
4274 4275
				break;
			}
4276 4277
			if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
			    em->start != start) {
4278
				write_unlock(&map->lock);
4279 4280 4281 4282 4283
				free_extent_map(em);
				break;
			}
			if (!test_range_bit(tree, em->start,
					    extent_map_end(em) - 1,
4284
					    EXTENT_LOCKED | EXTENT_WRITEBACK,
4285
					    0, NULL)) {
4286 4287 4288 4289 4290
				remove_extent_mapping(map, em);
				/* once for the rb tree */
				free_extent_map(em);
			}
			start = extent_map_end(em);
4291
			write_unlock(&map->lock);
4292 4293

			/* once for us */
4294 4295 4296
			free_extent_map(em);
		}
	}
4297
	return try_release_extent_state(map, tree, page, mask);
4298 4299
}

4300 4301 4302 4303 4304 4305 4306 4307 4308 4309 4310 4311 4312 4313 4314 4315
/*
 * 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;

4316
	while (1) {
4317 4318 4319
		len = last - offset;
		if (len == 0)
			break;
4320
		len = ALIGN(len, sectorsize);
4321
		em = get_extent(inode, NULL, 0, offset, len, 0);
4322
		if (IS_ERR_OR_NULL(em))
4323 4324 4325 4326 4327 4328 4329 4330 4331 4332 4333 4334 4335 4336 4337 4338 4339
			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
4340 4341 4342
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
4343
	int ret = 0;
Y
Yehuda Sadeh 已提交
4344 4345 4346
	u64 off = start;
	u64 max = start + len;
	u32 flags = 0;
J
Josef Bacik 已提交
4347 4348
	u32 found_type;
	u64 last;
4349
	u64 last_for_get_extent = 0;
Y
Yehuda Sadeh 已提交
4350
	u64 disko = 0;
4351
	u64 isize = i_size_read(inode);
J
Josef Bacik 已提交
4352
	struct btrfs_key found_key;
Y
Yehuda Sadeh 已提交
4353
	struct extent_map *em = NULL;
4354
	struct extent_state *cached_state = NULL;
J
Josef Bacik 已提交
4355
	struct btrfs_path *path;
4356
	struct btrfs_root *root = BTRFS_I(inode)->root;
Y
Yehuda Sadeh 已提交
4357
	int end = 0;
4358 4359 4360
	u64 em_start = 0;
	u64 em_len = 0;
	u64 em_end = 0;
Y
Yehuda Sadeh 已提交
4361 4362 4363 4364

	if (len == 0)
		return -EINVAL;

J
Josef Bacik 已提交
4365 4366 4367 4368 4369
	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
	path->leave_spinning = 1;

4370 4371
	start = round_down(start, BTRFS_I(inode)->root->sectorsize);
	len = round_up(max, BTRFS_I(inode)->root->sectorsize) - start;
4372

4373 4374 4375 4376
	/*
	 * lookup the last file extent.  We're not using i_size here
	 * because there might be preallocation past i_size
	 */
4377 4378
	ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode), -1,
				       0);
J
Josef Bacik 已提交
4379 4380 4381 4382 4383 4384 4385
	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]);
4386
	found_type = found_key.type;
J
Josef Bacik 已提交
4387

4388
	/* No extents, but there might be delalloc bits */
L
Li Zefan 已提交
4389
	if (found_key.objectid != btrfs_ino(inode) ||
J
Josef Bacik 已提交
4390
	    found_type != BTRFS_EXTENT_DATA_KEY) {
4391 4392 4393 4394 4395 4396 4397 4398 4399 4400 4401
		/* 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
4402
	}
4403
	btrfs_release_path(path);
J
Josef Bacik 已提交
4404

4405 4406 4407 4408 4409 4410 4411 4412 4413 4414
	/*
	 * 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
4415
	lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len - 1, 0,
4416
			 &cached_state);
4417

4418
	em = get_extent_skip_holes(inode, start, last_for_get_extent,
4419
				   get_extent);
Y
Yehuda Sadeh 已提交
4420 4421 4422 4423 4424 4425
	if (!em)
		goto out;
	if (IS_ERR(em)) {
		ret = PTR_ERR(em);
		goto out;
	}
J
Josef Bacik 已提交
4426

Y
Yehuda Sadeh 已提交
4427
	while (!end) {
4428
		u64 offset_in_extent = 0;
4429 4430 4431 4432 4433 4434 4435 4436 4437 4438 4439 4440

		/* 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
4441

4442 4443
		/*
		 * record the offset from the start of the extent
4444 4445 4446
		 * 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.
4447
		 */
4448 4449
		if (!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
			offset_in_extent = em_start - em->start;
4450
		em_end = extent_map_end(em);
4451
		em_len = em_end - em_start;
Y
Yehuda Sadeh 已提交
4452 4453 4454
		disko = 0;
		flags = 0;

4455 4456 4457 4458 4459 4460 4461
		/*
		 * bump off for our next call to get_extent
		 */
		off = extent_map_end(em);
		if (off >= max)
			end = 1;

4462
		if (em->block_start == EXTENT_MAP_LAST_BYTE) {
Y
Yehuda Sadeh 已提交
4463 4464
			end = 1;
			flags |= FIEMAP_EXTENT_LAST;
4465
		} else if (em->block_start == EXTENT_MAP_INLINE) {
Y
Yehuda Sadeh 已提交
4466 4467
			flags |= (FIEMAP_EXTENT_DATA_INLINE |
				  FIEMAP_EXTENT_NOT_ALIGNED);
4468
		} else if (em->block_start == EXTENT_MAP_DELALLOC) {
Y
Yehuda Sadeh 已提交
4469 4470
			flags |= (FIEMAP_EXTENT_DELALLOC |
				  FIEMAP_EXTENT_UNKNOWN);
4471 4472 4473
		} else if (fieinfo->fi_extents_max) {
			u64 bytenr = em->block_start -
				(em->start - em->orig_start);
4474

4475
			disko = em->block_start + offset_in_extent;
4476 4477 4478 4479

			/*
			 * As btrfs supports shared space, this information
			 * can be exported to userspace tools via
4480 4481 4482
			 * flag FIEMAP_EXTENT_SHARED.  If fi_extents_max == 0
			 * then we're just getting a count and we can skip the
			 * lookup stuff.
4483
			 */
4484 4485 4486 4487
			ret = btrfs_check_shared(NULL, root->fs_info,
						 root->objectid,
						 btrfs_ino(inode), bytenr);
			if (ret < 0)
4488
				goto out_free;
4489
			if (ret)
4490
				flags |= FIEMAP_EXTENT_SHARED;
4491
			ret = 0;
Y
Yehuda Sadeh 已提交
4492 4493 4494 4495 4496 4497
		}
		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
			flags |= FIEMAP_EXTENT_ENCODED;

		free_extent_map(em);
		em = NULL;
4498 4499
		if ((em_start >= last) || em_len == (u64)-1 ||
		   (last == (u64)-1 && isize <= em_end)) {
Y
Yehuda Sadeh 已提交
4500 4501 4502 4503
			flags |= FIEMAP_EXTENT_LAST;
			end = 1;
		}

4504 4505 4506 4507 4508 4509 4510 4511
		/* 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
4512 4513 4514
			flags |= FIEMAP_EXTENT_LAST;
			end = 1;
		}
4515 4516
		ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
					      em_len, flags);
4517 4518 4519
		if (ret) {
			if (ret == 1)
				ret = 0;
4520
			goto out_free;
4521
		}
Y
Yehuda Sadeh 已提交
4522 4523 4524 4525
	}
out_free:
	free_extent_map(em);
out:
4526
	btrfs_free_path(path);
L
Liu Bo 已提交
4527
	unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4528
			     &cached_state, GFP_NOFS);
Y
Yehuda Sadeh 已提交
4529 4530 4531
	return ret;
}

4532 4533
static void __free_extent_buffer(struct extent_buffer *eb)
{
4534
	btrfs_leak_debug_del(&eb->leak_list);
4535 4536 4537
	kmem_cache_free(extent_buffer_cache, eb);
}

4538
int extent_buffer_under_io(struct extent_buffer *eb)
4539 4540 4541 4542 4543 4544 4545 4546 4547
{
	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.
 */
4548
static void btrfs_release_extent_buffer_page(struct extent_buffer *eb)
4549 4550 4551 4552 4553 4554 4555
{
	unsigned long index;
	struct page *page;
	int mapped = !test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);

	BUG_ON(extent_buffer_under_io(eb));

4556 4557
	index = num_extent_pages(eb->start, eb->len);
	if (index == 0)
4558 4559 4560 4561
		return;

	do {
		index--;
4562
		page = eb->pages[index];
4563 4564 4565 4566 4567 4568 4569 4570 4571 4572 4573 4574 4575 4576 4577 4578 4579 4580 4581 4582 4583 4584 4585 4586 4587 4588 4589 4590 4591 4592
		if (page && mapped) {
			spin_lock(&page->mapping->private_lock);
			/*
			 * 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));
				/*
				 * We need to make sure we haven't be attached
				 * to a new eb.
				 */
				ClearPagePrivate(page);
				set_page_private(page, 0);
				/* One for the page private */
				page_cache_release(page);
			}
			spin_unlock(&page->mapping->private_lock);

		}
		if (page) {
			/* 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
		mark_extent_buffer_accessed(eb, NULL);
4775 4776 4777 4778 4779 4780 4781
		return eb;
	}
	rcu_read_unlock();

	return NULL;
}

4782 4783
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
4784
					       u64 start)
4785 4786 4787 4788 4789 4790 4791
{
	struct extent_buffer *eb, *exists = NULL;
	int ret;

	eb = find_extent_buffer(fs_info, start);
	if (eb)
		return eb;
4792
	eb = alloc_dummy_extent_buffer(fs_info, start);
4793 4794 4795 4796 4797 4798 4799 4800 4801 4802 4803 4804 4805 4806 4807 4808 4809 4810 4811 4812 4813 4814 4815 4816 4817 4818 4819 4820 4821 4822 4823 4824 4825 4826 4827 4828
	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

4829
struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
4830
					  u64 start)
4831
{
4832
	unsigned long len = fs_info->tree_root->nodesize;
4833 4834 4835 4836
	unsigned long num_pages = num_extent_pages(start, len);
	unsigned long i;
	unsigned long index = start >> PAGE_CACHE_SHIFT;
	struct extent_buffer *eb;
4837
	struct extent_buffer *exists = NULL;
4838
	struct page *p;
4839
	struct address_space *mapping = fs_info->btree_inode->i_mapping;
4840
	int uptodate = 1;
4841
	int ret;
4842

4843
	eb = find_extent_buffer(fs_info, start);
4844
	if (eb)
4845 4846
		return eb;

4847
	eb = __alloc_extent_buffer(fs_info, start, len);
4848
	if (!eb)
4849 4850
		return NULL;

4851
	for (i = 0; i < num_pages; i++, index++) {
4852
		p = find_or_create_page(mapping, index, GFP_NOFS);
4853
		if (!p)
4854
			goto free_eb;
J
Josef Bacik 已提交
4855 4856 4857 4858 4859 4860 4861 4862 4863 4864 4865 4866 4867 4868

		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);
4869
				page_cache_release(p);
4870
				mark_extent_buffer_accessed(exists, p);
J
Josef Bacik 已提交
4871 4872
				goto free_eb;
			}
4873
			exists = NULL;
J
Josef Bacik 已提交
4874

4875
			/*
J
Josef Bacik 已提交
4876 4877 4878 4879
			 * Do this so attach doesn't complain and we need to
			 * drop the ref the old guy had.
			 */
			ClearPagePrivate(p);
4880
			WARN_ON(PageDirty(p));
J
Josef Bacik 已提交
4881
			page_cache_release(p);
4882
		}
J
Josef Bacik 已提交
4883 4884
		attach_extent_buffer_page(eb, p);
		spin_unlock(&mapping->private_lock);
4885
		WARN_ON(PageDirty(p));
4886
		eb->pages[i] = p;
4887 4888
		if (!PageUptodate(p))
			uptodate = 0;
C
Chris Mason 已提交
4889 4890 4891 4892 4893

		/*
		 * see below about how we avoid a nasty race with release page
		 * and why we unlock later
		 */
4894 4895
	}
	if (uptodate)
4896
		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4897
again:
4898 4899 4900 4901
	ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
	if (ret)
		goto free_eb;

4902 4903 4904 4905
	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);
4906
	radix_tree_preload_end();
4907
	if (ret == -EEXIST) {
4908
		exists = find_extent_buffer(fs_info, start);
4909 4910 4911
		if (exists)
			goto free_eb;
		else
4912
			goto again;
4913 4914
	}
	/* add one reference for the tree */
4915
	check_buffer_tree_ref(eb);
4916
	set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
C
Chris Mason 已提交
4917 4918 4919 4920 4921 4922 4923 4924 4925 4926

	/*
	 * 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
	 */
4927 4928
	SetPageChecked(eb->pages[0]);
	for (i = 1; i < num_pages; i++) {
4929
		p = eb->pages[i];
4930 4931 4932 4933
		ClearPageChecked(p);
		unlock_page(p);
	}
	unlock_page(eb->pages[0]);
4934 4935
	return eb;

4936
free_eb:
4937
	WARN_ON(!atomic_dec_and_test(&eb->refs));
4938 4939 4940 4941
	for (i = 0; i < num_pages; i++) {
		if (eb->pages[i])
			unlock_page(eb->pages[i]);
	}
C
Chris Mason 已提交
4942

4943
	btrfs_release_extent_buffer(eb);
4944
	return exists;
4945 4946
}

4947 4948 4949 4950 4951 4952 4953 4954 4955
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 */
4956
static int release_extent_buffer(struct extent_buffer *eb)
4957 4958 4959
{
	WARN_ON(atomic_read(&eb->refs) == 0);
	if (atomic_dec_and_test(&eb->refs)) {
4960
		if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
4961
			struct btrfs_fs_info *fs_info = eb->fs_info;
4962

4963
			spin_unlock(&eb->refs_lock);
4964

4965 4966
			spin_lock(&fs_info->buffer_lock);
			radix_tree_delete(&fs_info->buffer_radix,
4967
					  eb->start >> PAGE_CACHE_SHIFT);
4968
			spin_unlock(&fs_info->buffer_lock);
4969 4970
		} else {
			spin_unlock(&eb->refs_lock);
4971
		}
4972 4973

		/* Should be safe to release our pages at this point */
4974
		btrfs_release_extent_buffer_page(eb);
4975 4976 4977 4978 4979 4980
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
		if (unlikely(test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))) {
			__free_extent_buffer(eb);
			return 1;
		}
#endif
4981
		call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
4982
		return 1;
4983 4984
	}
	spin_unlock(&eb->refs_lock);
4985 4986

	return 0;
4987 4988
}

4989 4990
void free_extent_buffer(struct extent_buffer *eb)
{
4991 4992
	int refs;
	int old;
4993 4994 4995
	if (!eb)
		return;

4996 4997 4998 4999 5000 5001 5002 5003 5004
	while (1) {
		refs = atomic_read(&eb->refs);
		if (refs <= 3)
			break;
		old = atomic_cmpxchg(&eb->refs, refs, refs - 1);
		if (old == refs)
			return;
	}

5005
	spin_lock(&eb->refs_lock);
5006 5007 5008 5009
	if (atomic_read(&eb->refs) == 2 &&
	    test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))
		atomic_dec(&eb->refs);

5010 5011
	if (atomic_read(&eb->refs) == 2 &&
	    test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
5012
	    !extent_buffer_under_io(eb) &&
5013 5014 5015 5016 5017 5018 5019
	    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.
	 */
5020
	release_extent_buffer(eb);
5021 5022 5023 5024 5025
}

void free_extent_buffer_stale(struct extent_buffer *eb)
{
	if (!eb)
5026 5027
		return;

5028 5029 5030
	spin_lock(&eb->refs_lock);
	set_bit(EXTENT_BUFFER_STALE, &eb->bflags);

5031
	if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
5032 5033
	    test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
		atomic_dec(&eb->refs);
5034
	release_extent_buffer(eb);
5035 5036
}

5037
void clear_extent_buffer_dirty(struct extent_buffer *eb)
5038 5039 5040 5041 5042 5043 5044 5045
{
	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++) {
5046
		page = eb->pages[i];
5047
		if (!PageDirty(page))
C
Chris Mason 已提交
5048 5049
			continue;

5050
		lock_page(page);
C
Chris Mason 已提交
5051 5052
		WARN_ON(!PagePrivate(page));

5053
		clear_page_dirty_for_io(page);
5054
		spin_lock_irq(&page->mapping->tree_lock);
5055 5056 5057 5058 5059
		if (!PageDirty(page)) {
			radix_tree_tag_clear(&page->mapping->page_tree,
						page_index(page),
						PAGECACHE_TAG_DIRTY);
		}
5060
		spin_unlock_irq(&page->mapping->tree_lock);
5061
		ClearPageError(page);
5062
		unlock_page(page);
5063
	}
5064
	WARN_ON(atomic_read(&eb->refs) == 0);
5065 5066
}

5067
int set_extent_buffer_dirty(struct extent_buffer *eb)
5068 5069 5070
{
	unsigned long i;
	unsigned long num_pages;
5071
	int was_dirty = 0;
5072

5073 5074
	check_buffer_tree_ref(eb);

5075
	was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
5076

5077
	num_pages = num_extent_pages(eb->start, eb->len);
5078
	WARN_ON(atomic_read(&eb->refs) == 0);
5079 5080
	WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));

5081
	for (i = 0; i < num_pages; i++)
5082
		set_page_dirty(eb->pages[i]);
5083
	return was_dirty;
5084 5085
}

5086
int clear_extent_buffer_uptodate(struct extent_buffer *eb)
5087 5088 5089 5090 5091
{
	unsigned long i;
	struct page *page;
	unsigned long num_pages;

5092
	clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5093
	num_pages = num_extent_pages(eb->start, eb->len);
5094
	for (i = 0; i < num_pages; i++) {
5095
		page = eb->pages[i];
C
Chris Mason 已提交
5096 5097
		if (page)
			ClearPageUptodate(page);
5098 5099 5100 5101
	}
	return 0;
}

5102
int set_extent_buffer_uptodate(struct extent_buffer *eb)
5103 5104 5105 5106 5107
{
	unsigned long i;
	struct page *page;
	unsigned long num_pages;

5108
	set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5109 5110
	num_pages = num_extent_pages(eb->start, eb->len);
	for (i = 0; i < num_pages; i++) {
5111
		page = eb->pages[i];
5112 5113 5114 5115 5116
		SetPageUptodate(page);
	}
	return 0;
}

5117
int extent_buffer_uptodate(struct extent_buffer *eb)
5118
{
5119
	return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5120 5121 5122
}

int read_extent_buffer_pages(struct extent_io_tree *tree,
5123
			     struct extent_buffer *eb, u64 start, int wait,
5124
			     get_extent_t *get_extent, int mirror_num)
5125 5126 5127 5128 5129 5130
{
	unsigned long i;
	unsigned long start_i;
	struct page *page;
	int err;
	int ret = 0;
5131 5132
	int locked_pages = 0;
	int all_uptodate = 1;
5133
	unsigned long num_pages;
5134
	unsigned long num_reads = 0;
5135
	struct bio *bio = NULL;
C
Chris Mason 已提交
5136
	unsigned long bio_flags = 0;
5137

5138
	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
5139 5140 5141 5142 5143 5144 5145 5146 5147 5148 5149 5150
		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++) {
5151
		page = eb->pages[i];
5152
		if (wait == WAIT_NONE) {
5153
			if (!trylock_page(page))
5154
				goto unlock_exit;
5155 5156 5157
		} else {
			lock_page(page);
		}
5158
		locked_pages++;
5159 5160
		if (!PageUptodate(page)) {
			num_reads++;
5161
			all_uptodate = 0;
5162
		}
5163 5164 5165
	}
	if (all_uptodate) {
		if (start_i == 0)
5166
			set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5167 5168 5169
		goto unlock_exit;
	}

5170
	clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
5171
	eb->read_mirror = 0;
5172
	atomic_set(&eb->io_pages, num_reads);
5173
	for (i = start_i; i < num_pages; i++) {
5174
		page = eb->pages[i];
5175
		if (!PageUptodate(page)) {
5176
			ClearPageError(page);
5177
			err = __extent_read_full_page(tree, page,
5178
						      get_extent, &bio,
5179 5180
						      mirror_num, &bio_flags,
						      READ | REQ_META);
C
Chris Mason 已提交
5181
			if (err)
5182 5183 5184 5185 5186 5187
				ret = err;
		} else {
			unlock_page(page);
		}
	}

5188
	if (bio) {
5189 5190
		err = submit_one_bio(READ | REQ_META, bio, mirror_num,
				     bio_flags);
5191 5192
		if (err)
			return err;
5193
	}
5194

5195
	if (ret || wait != WAIT_COMPLETE)
5196
		return ret;
C
Chris Mason 已提交
5197

5198
	for (i = start_i; i < num_pages; i++) {
5199
		page = eb->pages[i];
5200
		wait_on_page_locked(page);
C
Chris Mason 已提交
5201
		if (!PageUptodate(page))
5202 5203
			ret = -EIO;
	}
C
Chris Mason 已提交
5204

5205
	return ret;
5206 5207 5208

unlock_exit:
	i = start_i;
C
Chris Mason 已提交
5209
	while (locked_pages > 0) {
5210
		page = eb->pages[i];
5211 5212 5213 5214 5215
		i++;
		unlock_page(page);
		locked_pages--;
	}
	return ret;
5216 5217 5218 5219 5220 5221 5222 5223 5224 5225 5226 5227 5228 5229 5230 5231 5232
}

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);

5233
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5234

C
Chris Mason 已提交
5235
	while (len > 0) {
5236
		page = eb->pages[i];
5237 5238

		cur = min(len, (PAGE_CACHE_SIZE - offset));
5239
		kaddr = page_address(page);
5240 5241 5242 5243 5244 5245 5246 5247 5248
		memcpy(dst, kaddr + offset, cur);

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

5249 5250 5251 5252 5253 5254 5255 5256 5257 5258 5259 5260 5261 5262 5263 5264 5265 5266 5267
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) {
5268
		page = eb->pages[i];
5269 5270 5271 5272 5273 5274 5275 5276 5277 5278 5279 5280 5281 5282 5283 5284 5285

		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;
}

5286
int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
5287
			       unsigned long min_len, char **map,
5288
			       unsigned long *map_start,
5289
			       unsigned long *map_len)
5290 5291 5292 5293 5294 5295 5296 5297 5298 5299 5300 5301 5302 5303 5304 5305 5306 5307 5308
{
	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
5309

5310
	if (start + min_len > eb->len) {
J
Julia Lawall 已提交
5311
		WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
5312 5313
		       "wanted %lu %lu\n",
		       eb->start, eb->len, start, min_len);
5314
		return -EINVAL;
5315 5316
	}

5317
	p = eb->pages[i];
5318
	kaddr = page_address(p);
5319 5320 5321 5322 5323 5324 5325 5326 5327 5328 5329 5330 5331 5332 5333 5334 5335 5336 5337 5338 5339
	*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);

5340
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5341

C
Chris Mason 已提交
5342
	while (len > 0) {
5343
		page = eb->pages[i];
5344 5345 5346

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

5347
		kaddr = page_address(page);
5348 5349 5350 5351 5352 5353 5354 5355 5356 5357 5358 5359 5360 5361 5362 5363 5364 5365 5366 5367 5368 5369 5370 5371 5372 5373
		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);

5374
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5375

C
Chris Mason 已提交
5376
	while (len > 0) {
5377
		page = eb->pages[i];
5378 5379 5380
		WARN_ON(!PageUptodate(page));

		cur = min(len, PAGE_CACHE_SIZE - offset);
5381
		kaddr = page_address(page);
5382 5383 5384 5385 5386 5387 5388 5389 5390 5391 5392 5393 5394 5395 5396 5397 5398 5399 5400 5401 5402 5403
		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);

5404
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5405

C
Chris Mason 已提交
5406
	while (len > 0) {
5407
		page = eb->pages[i];
5408 5409 5410
		WARN_ON(!PageUptodate(page));

		cur = min(len, PAGE_CACHE_SIZE - offset);
5411
		kaddr = page_address(page);
5412 5413 5414 5415 5416 5417 5418 5419 5420 5421 5422 5423 5424 5425 5426 5427 5428 5429 5430 5431 5432 5433 5434
		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) &
5435
		(PAGE_CACHE_SIZE - 1);
5436

C
Chris Mason 已提交
5437
	while (len > 0) {
5438
		page = dst->pages[i];
5439 5440 5441 5442
		WARN_ON(!PageUptodate(page));

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

5443
		kaddr = page_address(page);
5444 5445 5446 5447 5448 5449 5450 5451 5452
		read_extent_buffer(src, kaddr + offset, src_offset, cur);

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

5453 5454 5455 5456 5457 5458
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;
}

5459 5460 5461 5462
static void copy_pages(struct page *dst_page, struct page *src_page,
		       unsigned long dst_off, unsigned long src_off,
		       unsigned long len)
{
5463
	char *dst_kaddr = page_address(dst_page);
5464
	char *src_kaddr;
5465
	int must_memmove = 0;
5466

5467
	if (dst_page != src_page) {
5468
		src_kaddr = page_address(src_page);
5469
	} else {
5470
		src_kaddr = dst_kaddr;
5471 5472
		if (areas_overlap(src_off, dst_off, len))
			must_memmove = 1;
5473
	}
5474

5475 5476 5477 5478
	if (must_memmove)
		memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
	else
		memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
5479 5480 5481 5482 5483 5484 5485 5486 5487 5488 5489 5490 5491
}

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) {
5492
		printk(KERN_ERR "BTRFS: memmove bogus src_offset %lu move "
C
Chris Mason 已提交
5493
		       "len %lu dst len %lu\n", src_offset, len, dst->len);
5494 5495 5496
		BUG_ON(1);
	}
	if (dst_offset + len > dst->len) {
5497
		printk(KERN_ERR "BTRFS: memmove bogus dst_offset %lu move "
C
Chris Mason 已提交
5498
		       "len %lu dst len %lu\n", dst_offset, len, dst->len);
5499 5500 5501
		BUG_ON(1);
	}

C
Chris Mason 已提交
5502
	while (len > 0) {
5503
		dst_off_in_page = (start_offset + dst_offset) &
5504
			(PAGE_CACHE_SIZE - 1);
5505
		src_off_in_page = (start_offset + src_offset) &
5506
			(PAGE_CACHE_SIZE - 1);
5507 5508 5509 5510 5511 5512 5513 5514 5515

		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));

5516
		copy_pages(dst->pages[dst_i], dst->pages[src_i],
5517 5518 5519 5520 5521 5522 5523 5524 5525 5526 5527 5528 5529 5530 5531 5532 5533 5534 5535 5536 5537
			   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) {
5538
		printk(KERN_ERR "BTRFS: memmove bogus src_offset %lu move "
C
Chris Mason 已提交
5539
		       "len %lu len %lu\n", src_offset, len, dst->len);
5540 5541 5542
		BUG_ON(1);
	}
	if (dst_offset + len > dst->len) {
5543
		printk(KERN_ERR "BTRFS: memmove bogus dst_offset %lu move "
C
Chris Mason 已提交
5544
		       "len %lu len %lu\n", dst_offset, len, dst->len);
5545 5546
		BUG_ON(1);
	}
5547
	if (dst_offset < src_offset) {
5548 5549 5550
		memcpy_extent_buffer(dst, dst_offset, src_offset, len);
		return;
	}
C
Chris Mason 已提交
5551
	while (len > 0) {
5552 5553 5554 5555
		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) &
5556
			(PAGE_CACHE_SIZE - 1);
5557
		src_off_in_page = (start_offset + src_end) &
5558
			(PAGE_CACHE_SIZE - 1);
5559 5560 5561

		cur = min_t(unsigned long, len, src_off_in_page + 1);
		cur = min(cur, dst_off_in_page + 1);
5562
		copy_pages(dst->pages[dst_i], dst->pages[src_i],
5563 5564 5565 5566 5567 5568 5569 5570
			   dst_off_in_page - cur + 1,
			   src_off_in_page - cur + 1, cur);

		dst_end -= cur;
		src_end -= cur;
		len -= cur;
	}
}
5571

5572
int try_release_extent_buffer(struct page *page)
5573
{
5574 5575
	struct extent_buffer *eb;

5576 5577 5578 5579 5580 5581 5582
	/*
	 * 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
5583
		return 1;
5584
	}
5585

5586 5587
	eb = (struct extent_buffer *)page->private;
	BUG_ON(!eb);
5588 5589

	/*
5590 5591 5592
	 * 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.
5593
	 */
5594
	spin_lock(&eb->refs_lock);
5595
	if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
5596 5597 5598
		spin_unlock(&eb->refs_lock);
		spin_unlock(&page->mapping->private_lock);
		return 0;
5599
	}
5600
	spin_unlock(&page->mapping->private_lock);
5601

5602
	/*
5603 5604
	 * 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.
5605
	 */
5606 5607 5608
	if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
		spin_unlock(&eb->refs_lock);
		return 0;
5609
	}
5610

5611
	return release_extent_buffer(eb);
5612
}