extent_io.c 136.6 KB
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#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/bio.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/page-flags.h>
#include <linux/spinlock.h>
#include <linux/blkdev.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/pagevec.h>
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#include <linux/prefetch.h>
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#include <linux/cleancache.h>
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#include "extent_io.h"
#include "extent_map.h"
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#include "ctree.h"
#include "btrfs_inode.h"
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#include "volumes.h"
19
#include "check-integrity.h"
20
#include "locking.h"
21
#include "rcu-string.h"
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#include "backref.h"
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static struct kmem_cache *extent_state_cache;
static struct kmem_cache *extent_buffer_cache;
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static struct bio_set *btrfs_bioset;
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static inline bool extent_state_in_tree(const struct extent_state *state)
{
	return !RB_EMPTY_NODE(&state->rb_node);
}

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

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

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

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

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

	while (!list_empty(&states)) {
		state = list_entry(states.next, struct extent_state, leak_list);
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		pr_err("BTRFS: state leak: start %llu end %llu state %lu in tree %d refs %d\n",
		       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 "
78 79
		       "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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96 97
	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)
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{
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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 long *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,
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			   struct extent_state *state, unsigned long *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 long *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 long *bits)
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{
	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);
436 437
	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;

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

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

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/*
 * utility function to clear some bits in an extent state struct.
507
 * it will optionally wake up any one waiting on this state (wake == 1).
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 *
 * If no bits are set on the state struct after clearing things, the
 * struct is freed and removed from the tree
 */
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static struct extent_state *clear_state_bit(struct extent_io_tree *tree,
					    struct extent_state *state,
514
					    unsigned long *bits, int wake)
515
{
516
	struct extent_state *next;
517
	unsigned long 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);
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			RB_CLEAR_NODE(&state->rb_node);
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			free_extent_state(state);
		} else {
			WARN_ON(1);
		}
	} else {
		merge_state(tree, state);
539
		next = next_state(state);
540
	}
541
	return next;
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}

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

	return prealloc;
}

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

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

585
	btrfs_debug_check_extent_io_range(tree, start, end);
586

587 588 589
	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)) {
		prealloc = alloc_extent_state(mask);
		if (!prealloc)
			return -ENOMEM;
	}

603
	spin_lock(&tree->lock);
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	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) {
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			if (clear)
				atomic_dec(&cached->refs);
616
			state = cached;
617
			goto hit_next;
618
		}
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		if (clear)
			free_extent_state(cached);
621
	}
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	/*
	 * this search will find the extents that end after
	 * our range starts
	 */
626
	node = tree_search(tree, start);
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	if (!node)
		goto out;
	state = rb_entry(node, struct extent_state, rb_node);
630
hit_next:
631 632 633
	if (state->start > end)
		goto out;
	WARN_ON(state->end < start);
634
	last_end = state->end;
635

636
	/* the state doesn't have the wanted bits, go ahead */
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	if (!(state->state & bits)) {
		state = next_state(state);
639
		goto next;
640
	}
641

642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658
	/*
	 *     | ---- 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) {
659 660
		prealloc = alloc_extent_state_atomic(prealloc);
		BUG_ON(!prealloc);
661
		err = split_state(tree, state, prealloc, start);
662 663 664
		if (err)
			extent_io_tree_panic(tree, err);

665 666 667 668
		prealloc = NULL;
		if (err)
			goto out;
		if (state->end <= end) {
669 670
			state = clear_state_bit(tree, state, &bits, wake);
			goto next;
671 672 673 674 675 676 677 678 679 680
		}
		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) {
681 682
		prealloc = alloc_extent_state_atomic(prealloc);
		BUG_ON(!prealloc);
683
		err = split_state(tree, state, prealloc, end + 1);
684 685 686
		if (err)
			extent_io_tree_panic(tree, err);

687 688
		if (wake)
			wake_up(&state->wq);
689

690
		clear_state_bit(tree, prealloc, &bits, wake);
J
Josef Bacik 已提交
691

692 693 694
		prealloc = NULL;
		goto out;
	}
695

696
	state = clear_state_bit(tree, state, &bits, wake);
697
next:
698 699 700
	if (last_end == (u64)-1)
		goto out;
	start = last_end + 1;
701
	if (start <= end && state && !need_resched())
702
		goto hit_next;
703 704 705
	goto search_again;

out:
706
	spin_unlock(&tree->lock);
707 708 709
	if (prealloc)
		free_extent_state(prealloc);

710
	return 0;
711 712 713 714

search_again:
	if (start > end)
		goto out;
715
	spin_unlock(&tree->lock);
716 717 718 719 720
	if (mask & __GFP_WAIT)
		cond_resched();
	goto again;
}

721 722
static void wait_on_state(struct extent_io_tree *tree,
			  struct extent_state *state)
723 724
		__releases(tree->lock)
		__acquires(tree->lock)
725 726 727
{
	DEFINE_WAIT(wait);
	prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
728
	spin_unlock(&tree->lock);
729
	schedule();
730
	spin_lock(&tree->lock);
731 732 733 734 735 736 737 738
	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
 */
739 740
static void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
			    unsigned long bits)
741 742 743 744
{
	struct extent_state *state;
	struct rb_node *node;

745
	btrfs_debug_check_extent_io_range(tree, start, end);
746

747
	spin_lock(&tree->lock);
748 749 750 751 752 753
again:
	while (1) {
		/*
		 * this search will find all the extents that end after
		 * our range starts
		 */
754
		node = tree_search(tree, start);
755
process_node:
756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775
		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;

776 777 778 779
		if (!cond_resched_lock(&tree->lock)) {
			node = rb_next(node);
			goto process_node;
		}
780 781
	}
out:
782
	spin_unlock(&tree->lock);
783 784
}

785
static void set_state_bits(struct extent_io_tree *tree,
786
			   struct extent_state *state,
787
			   unsigned long *bits)
788
{
789
	unsigned long bits_to_set = *bits & ~EXTENT_CTLBITS;
J
Josef Bacik 已提交
790

791
	set_state_cb(tree, state, bits);
792
	if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
793 794 795
		u64 range = state->end - state->start + 1;
		tree->dirty_bytes += range;
	}
796
	state->state |= bits_to_set;
797 798
}

799 800 801 802 803 804 805 806 807 808 809
static void cache_state(struct extent_state *state,
			struct extent_state **cached_ptr)
{
	if (cached_ptr && !(*cached_ptr)) {
		if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY)) {
			*cached_ptr = state;
			atomic_inc(&state->refs);
		}
	}
}

810
/*
811 812
 * 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.
813
 *
814 815 816
 * 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.
817
 *
818
 * [start, end] is inclusive This takes the tree lock.
819
 */
820

J
Jeff Mahoney 已提交
821 822
static int __must_check
__set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
823 824 825
		 unsigned long bits, unsigned long exclusive_bits,
		 u64 *failed_start, struct extent_state **cached_state,
		 gfp_t mask)
826 827 828 829
{
	struct extent_state *state;
	struct extent_state *prealloc = NULL;
	struct rb_node *node;
830 831
	struct rb_node **p;
	struct rb_node *parent;
832 833 834
	int err = 0;
	u64 last_start;
	u64 last_end;
835

836
	btrfs_debug_check_extent_io_range(tree, start, end);
837

838
	bits |= EXTENT_FIRST_DELALLOC;
839 840 841
again:
	if (!prealloc && (mask & __GFP_WAIT)) {
		prealloc = alloc_extent_state(mask);
842
		BUG_ON(!prealloc);
843 844
	}

845
	spin_lock(&tree->lock);
846 847
	if (cached_state && *cached_state) {
		state = *cached_state;
848
		if (state->start <= start && state->end > start &&
849
		    extent_state_in_tree(state)) {
850 851 852 853
			node = &state->rb_node;
			goto hit_next;
		}
	}
854 855 856 857
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
858
	node = tree_search_for_insert(tree, start, &p, &parent);
859
	if (!node) {
860 861
		prealloc = alloc_extent_state_atomic(prealloc);
		BUG_ON(!prealloc);
862 863
		err = insert_state(tree, prealloc, start, end,
				   &p, &parent, &bits);
864 865 866
		if (err)
			extent_io_tree_panic(tree, err);

867
		cache_state(prealloc, cached_state);
868 869 870 871
		prealloc = NULL;
		goto out;
	}
	state = rb_entry(node, struct extent_state, rb_node);
C
Chris Mason 已提交
872
hit_next:
873 874 875 876 877 878 879 880 881 882
	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) {
883
		if (state->state & exclusive_bits) {
884 885 886 887
			*failed_start = state->start;
			err = -EEXIST;
			goto out;
		}
888

889
		set_state_bits(tree, state, &bits);
890
		cache_state(state, cached_state);
891
		merge_state(tree, state);
892 893 894
		if (last_end == (u64)-1)
			goto out;
		start = last_end + 1;
895 896 897 898
		state = next_state(state);
		if (start < end && state && state->start == start &&
		    !need_resched())
			goto hit_next;
899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918
		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) {
919
		if (state->state & exclusive_bits) {
920 921 922 923
			*failed_start = start;
			err = -EEXIST;
			goto out;
		}
924 925 926

		prealloc = alloc_extent_state_atomic(prealloc);
		BUG_ON(!prealloc);
927
		err = split_state(tree, state, prealloc, start);
928 929 930
		if (err)
			extent_io_tree_panic(tree, err);

931 932 933 934
		prealloc = NULL;
		if (err)
			goto out;
		if (state->end <= end) {
935
			set_state_bits(tree, state, &bits);
936
			cache_state(state, cached_state);
937
			merge_state(tree, state);
938 939 940
			if (last_end == (u64)-1)
				goto out;
			start = last_end + 1;
941 942 943 944
			state = next_state(state);
			if (start < end && state && state->start == start &&
			    !need_resched())
				goto hit_next;
945 946 947 948 949 950 951 952 953 954 955 956 957 958 959
		}
		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
960
			this_end = last_start - 1;
961 962 963

		prealloc = alloc_extent_state_atomic(prealloc);
		BUG_ON(!prealloc);
964 965 966 967 968

		/*
		 * Avoid to free 'prealloc' if it can be merged with
		 * the later extent.
		 */
969
		err = insert_state(tree, prealloc, start, this_end,
970
				   NULL, NULL, &bits);
971 972 973
		if (err)
			extent_io_tree_panic(tree, err);

J
Josef Bacik 已提交
974 975
		cache_state(prealloc, cached_state);
		prealloc = NULL;
976 977 978 979 980 981 982 983 984 985
		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) {
986
		if (state->state & exclusive_bits) {
987 988 989 990
			*failed_start = start;
			err = -EEXIST;
			goto out;
		}
991 992 993

		prealloc = alloc_extent_state_atomic(prealloc);
		BUG_ON(!prealloc);
994
		err = split_state(tree, state, prealloc, end + 1);
995 996
		if (err)
			extent_io_tree_panic(tree, err);
997

998
		set_state_bits(tree, prealloc, &bits);
999
		cache_state(prealloc, cached_state);
1000 1001 1002 1003 1004 1005 1006 1007
		merge_state(tree, prealloc);
		prealloc = NULL;
		goto out;
	}

	goto search_again;

out:
1008
	spin_unlock(&tree->lock);
1009 1010 1011 1012 1013 1014 1015 1016
	if (prealloc)
		free_extent_state(prealloc);

	return err;

search_again:
	if (start > end)
		goto out;
1017
	spin_unlock(&tree->lock);
1018 1019 1020 1021 1022
	if (mask & __GFP_WAIT)
		cond_resched();
	goto again;
}

1023 1024 1025
int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
		   unsigned long bits, u64 * failed_start,
		   struct extent_state **cached_state, gfp_t mask)
J
Jeff Mahoney 已提交
1026 1027 1028 1029 1030 1031
{
	return __set_extent_bit(tree, start, end, bits, 0, failed_start,
				cached_state, mask);
}


J
Josef Bacik 已提交
1032
/**
L
Liu Bo 已提交
1033 1034
 * convert_extent_bit - convert all bits in a given range from one bit to
 * 			another
J
Josef Bacik 已提交
1035 1036 1037 1038 1039
 * @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
1040
 * @cached_state:	state that we're going to cache
J
Josef Bacik 已提交
1041 1042 1043 1044 1045 1046 1047 1048 1049
 * @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,
1050
		       unsigned long bits, unsigned long clear_bits,
1051
		       struct extent_state **cached_state, gfp_t mask)
J
Josef Bacik 已提交
1052 1053 1054 1055
{
	struct extent_state *state;
	struct extent_state *prealloc = NULL;
	struct rb_node *node;
1056 1057
	struct rb_node **p;
	struct rb_node *parent;
J
Josef Bacik 已提交
1058 1059 1060 1061
	int err = 0;
	u64 last_start;
	u64 last_end;

1062
	btrfs_debug_check_extent_io_range(tree, start, end);
1063

J
Josef Bacik 已提交
1064 1065 1066 1067 1068 1069 1070 1071
again:
	if (!prealloc && (mask & __GFP_WAIT)) {
		prealloc = alloc_extent_state(mask);
		if (!prealloc)
			return -ENOMEM;
	}

	spin_lock(&tree->lock);
1072 1073 1074
	if (cached_state && *cached_state) {
		state = *cached_state;
		if (state->start <= start && state->end > start &&
1075
		    extent_state_in_tree(state)) {
1076 1077 1078 1079 1080
			node = &state->rb_node;
			goto hit_next;
		}
	}

J
Josef Bacik 已提交
1081 1082 1083 1084
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1085
	node = tree_search_for_insert(tree, start, &p, &parent);
J
Josef Bacik 已提交
1086 1087
	if (!node) {
		prealloc = alloc_extent_state_atomic(prealloc);
1088 1089 1090 1091
		if (!prealloc) {
			err = -ENOMEM;
			goto out;
		}
1092 1093
		err = insert_state(tree, prealloc, start, end,
				   &p, &parent, &bits);
1094 1095
		if (err)
			extent_io_tree_panic(tree, err);
1096 1097
		cache_state(prealloc, cached_state);
		prealloc = NULL;
J
Josef Bacik 已提交
1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112
		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);
1113
		cache_state(state, cached_state);
1114
		state = clear_state_bit(tree, state, &clear_bits, 0);
J
Josef Bacik 已提交
1115 1116 1117
		if (last_end == (u64)-1)
			goto out;
		start = last_end + 1;
1118 1119 1120
		if (start < end && state && state->start == start &&
		    !need_resched())
			goto hit_next;
J
Josef Bacik 已提交
1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141
		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);
1142 1143 1144 1145
		if (!prealloc) {
			err = -ENOMEM;
			goto out;
		}
J
Josef Bacik 已提交
1146
		err = split_state(tree, state, prealloc, start);
1147 1148
		if (err)
			extent_io_tree_panic(tree, err);
J
Josef Bacik 已提交
1149 1150 1151 1152 1153
		prealloc = NULL;
		if (err)
			goto out;
		if (state->end <= end) {
			set_state_bits(tree, state, &bits);
1154
			cache_state(state, cached_state);
1155
			state = clear_state_bit(tree, state, &clear_bits, 0);
J
Josef Bacik 已提交
1156 1157 1158
			if (last_end == (u64)-1)
				goto out;
			start = last_end + 1;
1159 1160 1161
			if (start < end && state && state->start == start &&
			    !need_resched())
				goto hit_next;
J
Josef Bacik 已提交
1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179
		}
		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);
1180 1181 1182 1183
		if (!prealloc) {
			err = -ENOMEM;
			goto out;
		}
J
Josef Bacik 已提交
1184 1185 1186 1187 1188 1189

		/*
		 * Avoid to free 'prealloc' if it can be merged with
		 * the later extent.
		 */
		err = insert_state(tree, prealloc, start, this_end,
1190
				   NULL, NULL, &bits);
1191 1192
		if (err)
			extent_io_tree_panic(tree, err);
1193
		cache_state(prealloc, cached_state);
J
Josef Bacik 已提交
1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205
		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);
1206 1207 1208 1209
		if (!prealloc) {
			err = -ENOMEM;
			goto out;
		}
J
Josef Bacik 已提交
1210 1211

		err = split_state(tree, state, prealloc, end + 1);
1212 1213
		if (err)
			extent_io_tree_panic(tree, err);
J
Josef Bacik 已提交
1214 1215

		set_state_bits(tree, prealloc, &bits);
1216
		cache_state(prealloc, cached_state);
J
Josef Bacik 已提交
1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239
		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();
	goto again;
}

1240 1241 1242 1243
/* 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
1244
	return set_extent_bit(tree, start, end, EXTENT_DIRTY, NULL,
1245
			      NULL, mask);
1246 1247 1248
}

int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1249
		    unsigned long bits, gfp_t mask)
1250
{
J
Jeff Mahoney 已提交
1251
	return set_extent_bit(tree, start, end, bits, NULL,
1252
			      NULL, mask);
1253 1254 1255
}

int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1256
		      unsigned long bits, gfp_t mask)
1257
{
1258
	return clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask);
1259 1260 1261
}

int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
1262
			struct extent_state **cached_state, gfp_t mask)
1263 1264
{
	return set_extent_bit(tree, start, end,
1265
			      EXTENT_DELALLOC | EXTENT_UPTODATE,
J
Jeff Mahoney 已提交
1266
			      NULL, cached_state, mask);
1267 1268
}

1269 1270 1271 1272 1273 1274 1275 1276
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);
}

1277 1278 1279 1280
int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
		       gfp_t mask)
{
	return clear_extent_bit(tree, start, end,
1281
				EXTENT_DIRTY | EXTENT_DELALLOC |
1282
				EXTENT_DO_ACCOUNTING, 0, 0, NULL, mask);
1283 1284 1285 1286 1287
}

int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
		     gfp_t mask)
{
J
Jeff Mahoney 已提交
1288
	return set_extent_bit(tree, start, end, EXTENT_NEW, NULL,
1289
			      NULL, mask);
1290 1291 1292
}

int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
1293
			struct extent_state **cached_state, gfp_t mask)
1294
{
L
Liu Bo 已提交
1295
	return set_extent_bit(tree, start, end, EXTENT_UPTODATE, NULL,
J
Jeff Mahoney 已提交
1296
			      cached_state, mask);
1297 1298
}

1299 1300
int clear_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
			  struct extent_state **cached_state, gfp_t mask)
1301
{
1302
	return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
1303
				cached_state, mask);
1304 1305
}

C
Chris Mason 已提交
1306 1307 1308 1309
/*
 * either insert or lock state struct between start and end use mask to tell
 * us if waiting is desired.
 */
1310
int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1311
		     unsigned long bits, struct extent_state **cached_state)
1312 1313 1314 1315
{
	int err;
	u64 failed_start;
	while (1) {
J
Jeff Mahoney 已提交
1316 1317 1318
		err = __set_extent_bit(tree, start, end, EXTENT_LOCKED | bits,
				       EXTENT_LOCKED, &failed_start,
				       cached_state, GFP_NOFS);
1319
		if (err == -EEXIST) {
1320 1321
			wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
			start = failed_start;
1322
		} else
1323 1324 1325 1326 1327 1328
			break;
		WARN_ON(start > end);
	}
	return err;
}

1329
int lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1330
{
1331
	return lock_extent_bits(tree, start, end, 0, NULL);
1332 1333
}

1334
int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1335 1336 1337 1338
{
	int err;
	u64 failed_start;

J
Jeff Mahoney 已提交
1339 1340
	err = __set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
			       &failed_start, NULL, GFP_NOFS);
Y
Yan Zheng 已提交
1341 1342 1343
	if (err == -EEXIST) {
		if (failed_start > start)
			clear_extent_bit(tree, start, failed_start - 1,
1344
					 EXTENT_LOCKED, 1, 0, NULL, GFP_NOFS);
1345
		return 0;
Y
Yan Zheng 已提交
1346
	}
1347 1348 1349
	return 1;
}

1350 1351 1352 1353 1354 1355 1356
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);
}

1357
int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1358
{
1359
	return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
1360
				GFP_NOFS);
1361 1362
}

1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395
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 */
		account_page_redirty(page);
		__set_page_dirty_nobuffers(page);
		page_cache_release(page);
		index++;
	}
	return 0;
}

1396 1397 1398
/*
 * helper function to set both pages and extents in the tree writeback
 */
1399
static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1400 1401 1402 1403 1404 1405 1406
{
	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);
1407
		BUG_ON(!page); /* Pages should be in the extent_io_tree */
1408 1409 1410 1411 1412 1413 1414
		set_page_writeback(page);
		page_cache_release(page);
		index++;
	}
	return 0;
}

C
Chris Mason 已提交
1415 1416 1417 1418
/* 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'
 */
1419 1420
static struct extent_state *
find_first_extent_bit_state(struct extent_io_tree *tree,
1421
			    u64 start, unsigned long bits)
C
Chris Mason 已提交
1422 1423 1424 1425 1426 1427 1428 1429 1430
{
	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
1431
	if (!node)
C
Chris Mason 已提交
1432 1433
		goto out;

C
Chris Mason 已提交
1434
	while (1) {
C
Chris Mason 已提交
1435
		state = rb_entry(node, struct extent_state, rb_node);
C
Chris Mason 已提交
1436
		if (state->end >= start && (state->state & bits))
C
Chris Mason 已提交
1437
			return state;
C
Chris Mason 已提交
1438

C
Chris Mason 已提交
1439 1440 1441 1442 1443 1444 1445 1446
		node = rb_next(node);
		if (!node)
			break;
	}
out:
	return NULL;
}

1447 1448 1449 1450 1451
/*
 * 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.
 *
1452
 * If nothing was found, 1 is returned. If found something, return 0.
1453 1454
 */
int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1455
			  u64 *start_ret, u64 *end_ret, unsigned long bits,
1456
			  struct extent_state **cached_state)
1457 1458
{
	struct extent_state *state;
1459
	struct rb_node *n;
1460 1461 1462
	int ret = 1;

	spin_lock(&tree->lock);
1463 1464
	if (cached_state && *cached_state) {
		state = *cached_state;
1465
		if (state->end == start - 1 && extent_state_in_tree(state)) {
1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481
			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;
	}

1482
	state = find_first_extent_bit_state(tree, start, bits);
1483
got_it:
1484
	if (state) {
1485
		cache_state(state, cached_state);
1486 1487 1488 1489
		*start_ret = state->start;
		*end_ret = state->end;
		ret = 0;
	}
1490
out:
1491 1492 1493 1494
	spin_unlock(&tree->lock);
	return ret;
}

C
Chris Mason 已提交
1495 1496 1497 1498 1499 1500
/*
 * 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
1501
static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1502 1503
					u64 *start, u64 *end, u64 max_bytes,
					struct extent_state **cached_state)
1504 1505 1506 1507 1508 1509 1510
{
	struct rb_node *node;
	struct extent_state *state;
	u64 cur_start = *start;
	u64 found = 0;
	u64 total_bytes = 0;

1511
	spin_lock(&tree->lock);
C
Chris Mason 已提交
1512

1513 1514 1515 1516
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1517
	node = tree_search(tree, cur_start);
1518
	if (!node) {
1519 1520
		if (!found)
			*end = (u64)-1;
1521 1522 1523
		goto out;
	}

C
Chris Mason 已提交
1524
	while (1) {
1525
		state = rb_entry(node, struct extent_state, rb_node);
1526 1527
		if (found && (state->start != cur_start ||
			      (state->state & EXTENT_BOUNDARY))) {
1528 1529 1530 1531 1532 1533 1534
			goto out;
		}
		if (!(state->state & EXTENT_DELALLOC)) {
			if (!found)
				*end = state->end;
			goto out;
		}
1535
		if (!found) {
1536
			*start = state->start;
1537 1538 1539
			*cached_state = state;
			atomic_inc(&state->refs);
		}
1540 1541 1542 1543 1544
		found++;
		*end = state->end;
		cur_start = state->end + 1;
		node = rb_next(node);
		total_bytes += state->end - state->start + 1;
1545
		if (total_bytes >= max_bytes)
1546 1547
			break;
		if (!node)
1548 1549 1550
			break;
	}
out:
1551
	spin_unlock(&tree->lock);
1552 1553 1554
	return found;
}

1555 1556 1557
static noinline void __unlock_for_delalloc(struct inode *inode,
					   struct page *locked_page,
					   u64 start, u64 end)
C
Chris Mason 已提交
1558 1559 1560 1561 1562 1563 1564 1565 1566
{
	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)
1567
		return;
C
Chris Mason 已提交
1568

C
Chris Mason 已提交
1569
	while (nr_pages > 0) {
C
Chris Mason 已提交
1570
		ret = find_get_pages_contig(inode->i_mapping, index,
1571 1572
				     min_t(unsigned long, nr_pages,
				     ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603
		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
1604
	while (nrpages > 0) {
C
Chris Mason 已提交
1605
		ret = find_get_pages_contig(inode->i_mapping, index,
1606 1607
				     min_t(unsigned long,
				     nrpages, ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1608 1609 1610 1611 1612 1613 1614 1615 1616 1617
		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
			 */
1618
			if (pages[i] != locked_page) {
C
Chris Mason 已提交
1619
				lock_page(pages[i]);
1620 1621
				if (!PageDirty(pages[i]) ||
				    pages[i]->mapping != inode->i_mapping) {
1622 1623 1624 1625 1626 1627
					ret = -EAGAIN;
					unlock_page(pages[i]);
					page_cache_release(pages[i]);
					goto done;
				}
			}
C
Chris Mason 已提交
1628
			page_cache_release(pages[i]);
1629
			pages_locked++;
C
Chris Mason 已提交
1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651
		}
		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
 */
1652 1653 1654 1655
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
1656 1657 1658 1659
{
	u64 delalloc_start;
	u64 delalloc_end;
	u64 found;
1660
	struct extent_state *cached_state = NULL;
C
Chris Mason 已提交
1661 1662 1663 1664 1665 1666 1667 1668
	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,
1669
				    max_bytes, &cached_state);
C
Chris Mason 已提交
1670
	if (!found || delalloc_end <= *start) {
C
Chris Mason 已提交
1671 1672
		*start = delalloc_start;
		*end = delalloc_end;
1673
		free_extent_state(cached_state);
L
Liu Bo 已提交
1674
		return 0;
C
Chris Mason 已提交
1675 1676
	}

C
Chris Mason 已提交
1677 1678 1679 1680 1681
	/*
	 * 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
1682
	if (delalloc_start < *start)
C
Chris Mason 已提交
1683 1684
		delalloc_start = *start;

C
Chris Mason 已提交
1685 1686 1687
	/*
	 * make sure to limit the number of pages we try to lock down
	 */
1688 1689
	if (delalloc_end + 1 - delalloc_start > max_bytes)
		delalloc_end = delalloc_start + max_bytes - 1;
C
Chris Mason 已提交
1690

C
Chris Mason 已提交
1691 1692 1693 1694 1695 1696 1697
	/* 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
		 */
1698
		free_extent_state(cached_state);
1699
		cached_state = NULL;
C
Chris Mason 已提交
1700
		if (!loops) {
1701
			max_bytes = PAGE_CACHE_SIZE;
C
Chris Mason 已提交
1702 1703 1704 1705 1706 1707 1708
			loops = 1;
			goto again;
		} else {
			found = 0;
			goto out_failed;
		}
	}
1709
	BUG_ON(ret); /* Only valid values are 0 and -EAGAIN */
C
Chris Mason 已提交
1710 1711

	/* step three, lock the state bits for the whole range */
1712
	lock_extent_bits(tree, delalloc_start, delalloc_end, 0, &cached_state);
C
Chris Mason 已提交
1713 1714 1715

	/* then test to make sure it is all still delalloc */
	ret = test_range_bit(tree, delalloc_start, delalloc_end,
1716
			     EXTENT_DELALLOC, 1, cached_state);
C
Chris Mason 已提交
1717
	if (!ret) {
1718 1719
		unlock_extent_cached(tree, delalloc_start, delalloc_end,
				     &cached_state, GFP_NOFS);
C
Chris Mason 已提交
1720 1721 1722 1723 1724
		__unlock_for_delalloc(inode, locked_page,
			      delalloc_start, delalloc_end);
		cond_resched();
		goto again;
	}
1725
	free_extent_state(cached_state);
C
Chris Mason 已提交
1726 1727 1728 1729 1730 1731
	*start = delalloc_start;
	*end = delalloc_end;
out_failed:
	return found;
}

1732 1733 1734 1735
int extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
				 struct page *locked_page,
				 unsigned long clear_bits,
				 unsigned long page_ops)
C
Chris Mason 已提交
1736
{
1737
	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
C
Chris Mason 已提交
1738 1739 1740 1741 1742 1743
	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;
1744

1745
	clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1746
	if (page_ops == 0)
1747
		return 0;
C
Chris Mason 已提交
1748

C
Chris Mason 已提交
1749
	while (nr_pages > 0) {
C
Chris Mason 已提交
1750
		ret = find_get_pages_contig(inode->i_mapping, index,
1751 1752
				     min_t(unsigned long,
				     nr_pages, ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1753
		for (i = 0; i < ret; i++) {
1754

1755
			if (page_ops & PAGE_SET_PRIVATE2)
1756 1757
				SetPagePrivate2(pages[i]);

C
Chris Mason 已提交
1758 1759 1760 1761
			if (pages[i] == locked_page) {
				page_cache_release(pages[i]);
				continue;
			}
1762
			if (page_ops & PAGE_CLEAR_DIRTY)
C
Chris Mason 已提交
1763
				clear_page_dirty_for_io(pages[i]);
1764
			if (page_ops & PAGE_SET_WRITEBACK)
C
Chris Mason 已提交
1765
				set_page_writeback(pages[i]);
1766
			if (page_ops & PAGE_END_WRITEBACK)
C
Chris Mason 已提交
1767
				end_page_writeback(pages[i]);
1768
			if (page_ops & PAGE_UNLOCK)
1769
				unlock_page(pages[i]);
C
Chris Mason 已提交
1770 1771 1772 1773 1774 1775 1776 1777 1778
			page_cache_release(pages[i]);
		}
		nr_pages -= ret;
		index += ret;
		cond_resched();
	}
	return 0;
}

C
Chris Mason 已提交
1779 1780 1781 1782 1783
/*
 * 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.
 */
1784 1785
u64 count_range_bits(struct extent_io_tree *tree,
		     u64 *start, u64 search_end, u64 max_bytes,
1786
		     unsigned long bits, int contig)
1787 1788 1789 1790 1791
{
	struct rb_node *node;
	struct extent_state *state;
	u64 cur_start = *start;
	u64 total_bytes = 0;
1792
	u64 last = 0;
1793 1794
	int found = 0;

1795
	if (WARN_ON(search_end <= cur_start))
1796 1797
		return 0;

1798
	spin_lock(&tree->lock);
1799 1800 1801 1802 1803 1804 1805 1806
	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.
	 */
1807
	node = tree_search(tree, cur_start);
C
Chris Mason 已提交
1808
	if (!node)
1809 1810
		goto out;

C
Chris Mason 已提交
1811
	while (1) {
1812 1813 1814
		state = rb_entry(node, struct extent_state, rb_node);
		if (state->start > search_end)
			break;
1815 1816 1817
		if (contig && found && state->start > last + 1)
			break;
		if (state->end >= cur_start && (state->state & bits) == bits) {
1818 1819 1820 1821 1822
			total_bytes += min(search_end, state->end) + 1 -
				       max(cur_start, state->start);
			if (total_bytes >= max_bytes)
				break;
			if (!found) {
1823
				*start = max(cur_start, state->start);
1824 1825
				found = 1;
			}
1826 1827 1828
			last = state->end;
		} else if (contig && found) {
			break;
1829 1830 1831 1832 1833 1834
		}
		node = rb_next(node);
		if (!node)
			break;
	}
out:
1835
	spin_unlock(&tree->lock);
1836 1837
	return total_bytes;
}
1838

C
Chris Mason 已提交
1839 1840 1841 1842
/*
 * set the private field for a given byte offset in the tree.  If there isn't
 * an extent_state there already, this does nothing.
 */
1843
static int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
1844 1845 1846 1847 1848
{
	struct rb_node *node;
	struct extent_state *state;
	int ret = 0;

1849
	spin_lock(&tree->lock);
1850 1851 1852 1853
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1854
	node = tree_search(tree, start);
1855
	if (!node) {
1856 1857 1858 1859 1860 1861 1862 1863 1864 1865
		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:
1866
	spin_unlock(&tree->lock);
1867 1868 1869 1870 1871 1872 1873 1874 1875
	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;

1876
	spin_lock(&tree->lock);
1877 1878 1879 1880
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1881
	node = tree_search(tree, start);
1882
	if (!node) {
1883 1884 1885 1886 1887 1888 1889 1890 1891 1892
		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:
1893
	spin_unlock(&tree->lock);
1894 1895 1896 1897 1898
	return ret;
}

/*
 * searches a range in the state tree for a given mask.
1899
 * If 'filled' == 1, this returns 1 only if every extent in the tree
1900 1901 1902 1903
 * 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,
1904
		   unsigned long bits, int filled, struct extent_state *cached)
1905 1906 1907 1908 1909
{
	struct extent_state *state = NULL;
	struct rb_node *node;
	int bitset = 0;

1910
	spin_lock(&tree->lock);
1911
	if (cached && extent_state_in_tree(cached) && cached->start <= start &&
1912
	    cached->end > start)
1913 1914 1915
		node = &cached->rb_node;
	else
		node = tree_search(tree, start);
1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934
	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;
		}
1935 1936 1937 1938

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

1939 1940 1941 1942 1943 1944 1945 1946 1947 1948
		start = state->end + 1;
		if (start > end)
			break;
		node = rb_next(node);
		if (!node) {
			if (filled)
				bitset = 0;
			break;
		}
	}
1949
	spin_unlock(&tree->lock);
1950 1951 1952 1953 1954 1955 1956
	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
 */
1957
static void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
1958
{
M
Miao Xie 已提交
1959
	u64 start = page_offset(page);
1960
	u64 end = start + PAGE_CACHE_SIZE - 1;
1961
	if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1962 1963 1964
		SetPageUptodate(page);
}

1965
int free_io_failure(struct inode *inode, struct io_failure_record *rec)
1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977
{
	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
1978 1979 1980 1981 1982
	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;
1983 1984 1985 1986 1987 1988 1989 1990 1991 1992

	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.
1993
 * to avoid any synchronization issues, wait for the data after writing, which
1994 1995 1996 1997
 * 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.
 */
1998 1999
int repair_io_failure(struct inode *inode, u64 start, u64 length, u64 logical,
		      struct page *page, unsigned int pg_offset, int mirror_num)
2000
{
2001
	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2002 2003 2004 2005 2006
	struct bio *bio;
	struct btrfs_device *dev;
	u64 map_length = 0;
	u64 sector;
	struct btrfs_bio *bbio = NULL;
D
David Woodhouse 已提交
2007
	struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
2008 2009
	int ret;

2010
	ASSERT(!(fs_info->sb->s_flags & MS_RDONLY));
2011 2012
	BUG_ON(!mirror_num);

D
David Woodhouse 已提交
2013 2014 2015 2016
	/* we can't repair anything in raid56 yet */
	if (btrfs_is_parity_mirror(map_tree, logical, length, mirror_num))
		return 0;

2017
	bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2018 2019
	if (!bio)
		return -EIO;
2020
	bio->bi_iter.bi_size = 0;
2021 2022
	map_length = length;

2023
	ret = btrfs_map_block(fs_info, WRITE, logical,
2024 2025 2026 2027 2028 2029 2030
			      &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;
2031
	bio->bi_iter.bi_sector = sector;
2032 2033 2034 2035 2036 2037 2038
	dev = bbio->stripes[mirror_num-1].dev;
	kfree(bbio);
	if (!dev || !dev->bdev || !dev->writeable) {
		bio_put(bio);
		return -EIO;
	}
	bio->bi_bdev = dev->bdev;
2039
	bio_add_page(bio, page, length, pg_offset);
2040

2041
	if (btrfsic_submit_bio_wait(WRITE_SYNC, bio)) {
2042 2043
		/* try to remap that extent elsewhere? */
		bio_put(bio);
2044
		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
2045 2046 2047
		return -EIO;
	}

2048
	printk_ratelimited_in_rcu(KERN_INFO
2049 2050 2051
				  "BTRFS: read error corrected: ino %llu off %llu (dev %s sector %llu)\n",
				  btrfs_ino(inode), start,
				  rcu_str_deref(dev->name), sector);
2052 2053 2054 2055
	bio_put(bio);
	return 0;
}

2056 2057 2058 2059 2060
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);
2061
	int ret = 0;
2062

2063 2064 2065
	if (root->fs_info->sb->s_flags & MS_RDONLY)
		return -EROFS;

2066 2067
	for (i = 0; i < num_pages; i++) {
		struct page *p = extent_buffer_page(eb, i);
2068 2069 2070 2071

		ret = repair_io_failure(root->fs_info->btree_inode, start,
					PAGE_CACHE_SIZE, start, p,
					start - page_offset(p), mirror_num);
2072 2073 2074 2075 2076 2077 2078 2079
		if (ret)
			break;
		start += PAGE_CACHE_SIZE;
	}

	return ret;
}

2080 2081 2082 2083
/*
 * 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
 */
2084 2085
int clean_io_failure(struct inode *inode, u64 start, struct page *page,
		     unsigned int pg_offset)
2086 2087 2088 2089
{
	u64 private;
	u64 private_failure;
	struct io_failure_record *failrec;
2090
	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114
	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;
	}
2115 2116
	if (fs_info->sb->s_flags & MS_RDONLY)
		goto out;
2117 2118 2119 2120 2121 2122 2123

	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);

2124 2125
	if (state && state->start <= failrec->start &&
	    state->end >= failrec->start + failrec->len - 1) {
2126 2127
		num_copies = btrfs_num_copies(fs_info, failrec->logical,
					      failrec->len);
2128
		if (num_copies > 1)  {
2129
			repair_io_failure(inode, start, failrec->len,
2130
					  failrec->logical, page,
2131
					  pg_offset, failrec->failed_mirror);
2132 2133 2134 2135
		}
	}

out:
2136
	free_io_failure(inode, failrec);
2137

2138
	return 0;
2139 2140
}

2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174
/*
 * 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);

		failrec = (struct io_failure_record *)state->private;
		free_extent_state(state);
		kfree(failrec);

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

2175 2176
int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
				struct io_failure_record **failrec_ret)
2177
{
2178
	struct io_failure_record *failrec;
2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191
	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;
2192

2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206
		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;
		}

2207
		if (em->start > start || em->start + em->len <= start) {
2208 2209 2210 2211
			free_extent_map(em);
			em = NULL;
		}
		read_unlock(&em_tree->lock);
2212
		if (!em) {
2213 2214 2215
			kfree(failrec);
			return -EIO;
		}
2216

2217 2218 2219 2220 2221 2222 2223 2224
		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);
		}
2225 2226 2227 2228

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

2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247
		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;
2248
		pr_debug("Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu, validation=%d\n",
2249 2250 2251 2252 2253 2254 2255 2256
			 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.
		 */
	}
2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267

	*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;

2268 2269
	num_copies = btrfs_num_copies(BTRFS_I(inode)->root->fs_info,
				      failrec->logical, failrec->len);
2270 2271 2272 2273 2274 2275
	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.
		 */
2276
		pr_debug("Check Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d\n",
2277
			 num_copies, failrec->this_mirror, failed_mirror);
2278
		return 0;
2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314
	}

	/*
	 * 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++;
	}

2315
	if (failrec->this_mirror > num_copies) {
2316
		pr_debug("Check Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d\n",
2317
			 num_copies, failrec->this_mirror, failed_mirror);
2318
		return 0;
2319 2320
	}

2321 2322 2323 2324 2325 2326 2327
	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,
2328
				    bio_end_io_t *endio_func, void *data)
2329 2330 2331 2332 2333
{
	struct bio *bio;
	struct btrfs_io_bio *btrfs_failed_bio;
	struct btrfs_io_bio *btrfs_bio;

2334
	bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2335 2336 2337 2338
	if (!bio)
		return NULL;

	bio->bi_end_io = endio_func;
2339
	bio->bi_iter.bi_sector = failrec->logical >> 9;
2340
	bio->bi_bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
2341
	bio->bi_iter.bi_size = 0;
2342
	bio->bi_private = data;
2343

2344 2345 2346 2347 2348 2349 2350
	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;
2351 2352
		icsum *= csum_size;
		memcpy(btrfs_bio->csum, btrfs_failed_bio->csum + icsum,
2353 2354 2355
		       csum_size);
	}

2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399
	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),
2400 2401
				      (int)phy_offset, failed_bio->bi_end_io,
				      NULL);
2402 2403 2404 2405
	if (!bio) {
		free_io_failure(inode, failrec);
		return -EIO;
	}
2406

2407 2408
	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);
2409

2410 2411 2412
	ret = tree->ops->submit_bio_hook(inode, read_mode, bio,
					 failrec->this_mirror,
					 failrec->bio_flags, 0);
2413
	if (ret) {
2414
		free_io_failure(inode, failrec);
2415 2416 2417
		bio_put(bio);
	}

2418
	return ret;
2419 2420
}

2421 2422
/* lots and lots of room for performance fixes in the end_bio funcs */

2423 2424 2425 2426
int end_extent_writepage(struct page *page, int err, u64 start, u64 end)
{
	int uptodate = (err == 0);
	struct extent_io_tree *tree;
2427
	int ret = 0;
2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440

	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);
2441 2442
		ret = ret < 0 ? ret : -EIO;
		mapping_set_error(page->mapping, ret);
2443 2444 2445 2446
	}
	return 0;
}

2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457
/*
 * 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)
{
2458
	struct bio_vec *bvec;
2459 2460
	u64 start;
	u64 end;
2461
	int i;
2462

2463
	bio_for_each_segment_all(bvec, bio, i) {
2464
		struct page *page = bvec->bv_page;
2465

2466 2467 2468 2469 2470
		/* 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.  */
2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481
		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);
		}
2482

2483 2484
		start = page_offset(page);
		end = start + bvec->bv_offset + bvec->bv_len - 1;
2485

2486 2487
		if (end_extent_writepage(page, err, start, end))
			continue;
2488

2489
		end_page_writeback(page);
2490
	}
2491

2492 2493 2494
	bio_put(bio);
}

2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506
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);
}

2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519
/*
 * 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)
{
2520
	struct bio_vec *bvec;
2521
	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
2522
	struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
2523
	struct extent_io_tree *tree;
2524
	u64 offset = 0;
2525 2526
	u64 start;
	u64 end;
2527
	u64 len;
2528 2529
	u64 extent_start = 0;
	u64 extent_len = 0;
2530
	int mirror;
2531
	int ret;
2532
	int i;
2533

2534 2535 2536
	if (err)
		uptodate = 0;

2537
	bio_for_each_segment_all(bvec, bio, i) {
2538
		struct page *page = bvec->bv_page;
2539
		struct inode *inode = page->mapping->host;
2540

2541
		pr_debug("end_bio_extent_readpage: bi_sector=%llu, err=%d, "
2542
			 "mirror=%u\n", (u64)bio->bi_iter.bi_sector, err,
2543
			 io_bio->mirror_num);
2544
		tree = &BTRFS_I(inode)->io_tree;
2545

2546 2547 2548 2549 2550
		/* 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.  */
2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561
		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);
		}
2562

2563 2564
		start = page_offset(page);
		end = start + bvec->bv_offset + bvec->bv_len - 1;
2565
		len = bvec->bv_len;
2566

2567
		mirror = io_bio->mirror_num;
2568 2569
		if (likely(uptodate && tree->ops &&
			   tree->ops->readpage_end_io_hook)) {
2570 2571 2572
			ret = tree->ops->readpage_end_io_hook(io_bio, offset,
							      page, start, end,
							      mirror);
2573
			if (ret)
2574
				uptodate = 0;
2575
			else
2576
				clean_io_failure(inode, start, page, 0);
2577
		}
2578

2579 2580 2581 2582
		if (likely(uptodate))
			goto readpage_ok;

		if (tree->ops && tree->ops->readpage_io_failed_hook) {
2583
			ret = tree->ops->readpage_io_failed_hook(page, mirror);
2584 2585 2586
			if (!ret && !err &&
			    test_bit(BIO_UPTODATE, &bio->bi_flags))
				uptodate = 1;
2587
		} else {
2588 2589 2590 2591 2592 2593 2594 2595 2596 2597
			/*
			 * 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.
			 */
2598 2599
			ret = bio_readpage_error(bio, offset, page, start, end,
						 mirror);
2600
			if (ret == 0) {
2601 2602
				uptodate =
					test_bit(BIO_UPTODATE, &bio->bi_flags);
2603 2604
				if (err)
					uptodate = 0;
2605
				offset += len;
2606 2607 2608
				continue;
			}
		}
2609
readpage_ok:
2610
		if (likely(uptodate)) {
2611 2612
			loff_t i_size = i_size_read(inode);
			pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
2613
			unsigned off;
2614 2615

			/* Zero out the end if this page straddles i_size */
2616 2617 2618
			off = i_size & (PAGE_CACHE_SIZE-1);
			if (page->index == end_index && off)
				zero_user_segment(page, off, PAGE_CACHE_SIZE);
2619
			SetPageUptodate(page);
2620
		} else {
2621 2622
			ClearPageUptodate(page);
			SetPageError(page);
2623
		}
2624
		unlock_page(page);
2625
		offset += len;
2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647

		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;
		}
2648
	}
2649

2650 2651 2652
	if (extent_len)
		endio_readpage_release_extent(tree, extent_start, extent_len,
					      uptodate);
2653 2654
	if (io_bio->end_io)
		io_bio->end_io(io_bio, err);
2655 2656 2657
	bio_put(bio);
}

2658 2659 2660 2661
/*
 * 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
 */
2662 2663 2664
struct bio *
btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
		gfp_t gfp_flags)
2665
{
2666
	struct btrfs_io_bio *btrfs_bio;
2667 2668
	struct bio *bio;

2669
	bio = bio_alloc_bioset(gfp_flags, nr_vecs, btrfs_bioset);
2670 2671

	if (bio == NULL && (current->flags & PF_MEMALLOC)) {
2672 2673 2674 2675
		while (!bio && (nr_vecs /= 2)) {
			bio = bio_alloc_bioset(gfp_flags,
					       nr_vecs, btrfs_bioset);
		}
2676 2677 2678 2679
	}

	if (bio) {
		bio->bi_bdev = bdev;
2680
		bio->bi_iter.bi_sector = first_sector;
2681 2682 2683 2684
		btrfs_bio = btrfs_io_bio(bio);
		btrfs_bio->csum = NULL;
		btrfs_bio->csum_allocated = NULL;
		btrfs_bio->end_io = NULL;
2685 2686 2687 2688
	}
	return bio;
}

2689 2690
struct bio *btrfs_bio_clone(struct bio *bio, gfp_t gfp_mask)
{
2691 2692
	struct btrfs_io_bio *btrfs_bio;
	struct bio *new;
2693

2694 2695 2696 2697 2698 2699 2700 2701 2702
	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;
}
2703 2704 2705 2706

/* this also allocates from the btrfs_bioset */
struct bio *btrfs_io_bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
{
2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717
	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;
2718 2719 2720
}


2721 2722
static int __must_check submit_one_bio(int rw, struct bio *bio,
				       int mirror_num, unsigned long bio_flags)
2723 2724
{
	int ret = 0;
2725 2726 2727 2728 2729
	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
2730
	start = page_offset(page) + bvec->bv_offset;
2731

2732
	bio->bi_private = NULL;
2733 2734 2735

	bio_get(bio);

2736
	if (tree->ops && tree->ops->submit_bio_hook)
2737
		ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
2738
					   mirror_num, bio_flags, start);
2739
	else
2740
		btrfsic_submit_bio(rw, bio);
2741

2742 2743 2744 2745 2746 2747
	if (bio_flagged(bio, BIO_EOPNOTSUPP))
		ret = -EOPNOTSUPP;
	bio_put(bio);
	return ret;
}

2748
static int merge_bio(int rw, struct extent_io_tree *tree, struct page *page,
2749 2750 2751 2752 2753
		     unsigned long offset, size_t size, struct bio *bio,
		     unsigned long bio_flags)
{
	int ret = 0;
	if (tree->ops && tree->ops->merge_bio_hook)
2754
		ret = tree->ops->merge_bio_hook(rw, page, offset, size, bio,
2755 2756 2757 2758 2759 2760
						bio_flags);
	BUG_ON(ret < 0);
	return ret;

}

2761 2762 2763 2764 2765 2766
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,
2767
			      bio_end_io_t end_io_func,
C
Chris Mason 已提交
2768 2769 2770
			      int mirror_num,
			      unsigned long prev_bio_flags,
			      unsigned long bio_flags)
2771 2772 2773 2774
{
	int ret = 0;
	struct bio *bio;
	int nr;
C
Chris Mason 已提交
2775 2776 2777
	int contig = 0;
	int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
	int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
2778
	size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
2779 2780 2781

	if (bio_ret && *bio_ret) {
		bio = *bio_ret;
C
Chris Mason 已提交
2782
		if (old_compressed)
2783
			contig = bio->bi_iter.bi_sector == sector;
C
Chris Mason 已提交
2784
		else
K
Kent Overstreet 已提交
2785
			contig = bio_end_sector(bio) == sector;
C
Chris Mason 已提交
2786 2787

		if (prev_bio_flags != bio_flags || !contig ||
2788
		    merge_bio(rw, tree, page, offset, page_size, bio, bio_flags) ||
C
Chris Mason 已提交
2789 2790 2791
		    bio_add_page(bio, page, page_size, offset) < page_size) {
			ret = submit_one_bio(rw, bio, mirror_num,
					     prev_bio_flags);
2792 2793
			if (ret < 0)
				return ret;
2794 2795 2796 2797 2798
			bio = NULL;
		} else {
			return 0;
		}
	}
C
Chris Mason 已提交
2799 2800 2801 2802 2803
	if (this_compressed)
		nr = BIO_MAX_PAGES;
	else
		nr = bio_get_nr_vecs(bdev);

2804
	bio = btrfs_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
2805 2806
	if (!bio)
		return -ENOMEM;
2807

C
Chris Mason 已提交
2808
	bio_add_page(bio, page, page_size, offset);
2809 2810
	bio->bi_end_io = end_io_func;
	bio->bi_private = tree;
2811

C
Chris Mason 已提交
2812
	if (bio_ret)
2813
		*bio_ret = bio;
C
Chris Mason 已提交
2814
	else
C
Chris Mason 已提交
2815
		ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
2816 2817 2818 2819

	return ret;
}

2820 2821
static void attach_extent_buffer_page(struct extent_buffer *eb,
				      struct page *page)
2822 2823 2824 2825
{
	if (!PagePrivate(page)) {
		SetPagePrivate(page);
		page_cache_get(page);
J
Josef Bacik 已提交
2826 2827 2828
		set_page_private(page, (unsigned long)eb);
	} else {
		WARN_ON(page->private != (unsigned long)eb);
2829 2830 2831
	}
}

J
Josef Bacik 已提交
2832
void set_page_extent_mapped(struct page *page)
2833
{
J
Josef Bacik 已提交
2834 2835 2836 2837 2838
	if (!PagePrivate(page)) {
		SetPagePrivate(page);
		page_cache_get(page);
		set_page_private(page, EXTENT_PAGE_PRIVATE);
	}
2839 2840
}

2841 2842 2843 2844 2845 2846 2847 2848 2849
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;
2850
		if (extent_map_in_tree(em) && start >= em->start &&
2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867
		    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;
}
2868 2869 2870 2871
/*
 * 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)
2872
 * XXX JDM: This needs looking at to ensure proper page locking
2873
 */
2874 2875 2876
static int __do_readpage(struct extent_io_tree *tree,
			 struct page *page,
			 get_extent_t *get_extent,
2877
			 struct extent_map **em_cached,
2878 2879
			 struct bio **bio, int mirror_num,
			 unsigned long *bio_flags, int rw)
2880 2881
{
	struct inode *inode = page->mapping->host;
M
Miao Xie 已提交
2882
	u64 start = page_offset(page);
2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894
	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;
2895
	int parent_locked = *bio_flags & EXTENT_BIO_PARENT_LOCKED;
2896
	size_t pg_offset = 0;
2897
	size_t iosize;
C
Chris Mason 已提交
2898
	size_t disk_io_size;
2899
	size_t blocksize = inode->i_sb->s_blocksize;
2900
	unsigned long this_bio_flag = *bio_flags & EXTENT_BIO_PARENT_LOCKED;
2901 2902 2903

	set_page_extent_mapped(page);

2904
	end = page_end;
D
Dan Magenheimer 已提交
2905 2906 2907
	if (!PageUptodate(page)) {
		if (cleancache_get_page(page) == 0) {
			BUG_ON(blocksize != PAGE_SIZE);
2908
			unlock_extent(tree, start, end);
D
Dan Magenheimer 已提交
2909 2910 2911 2912
			goto out;
		}
	}

C
Chris Mason 已提交
2913 2914 2915 2916 2917 2918
	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;
2919
			userpage = kmap_atomic(page);
C
Chris Mason 已提交
2920 2921
			memset(userpage + zero_offset, 0, iosize);
			flush_dcache_page(page);
2922
			kunmap_atomic(userpage);
C
Chris Mason 已提交
2923 2924
		}
	}
2925
	while (cur <= end) {
2926 2927
		unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;

2928 2929
		if (cur >= last_byte) {
			char *userpage;
2930 2931
			struct extent_state *cached = NULL;

2932
			iosize = PAGE_CACHE_SIZE - pg_offset;
2933
			userpage = kmap_atomic(page);
2934
			memset(userpage + pg_offset, 0, iosize);
2935
			flush_dcache_page(page);
2936
			kunmap_atomic(userpage);
2937
			set_extent_uptodate(tree, cur, cur + iosize - 1,
2938
					    &cached, GFP_NOFS);
2939 2940 2941 2942
			if (!parent_locked)
				unlock_extent_cached(tree, cur,
						     cur + iosize - 1,
						     &cached, GFP_NOFS);
2943 2944
			break;
		}
2945 2946
		em = __get_extent_map(inode, page, pg_offset, cur,
				      end - cur + 1, get_extent, em_cached);
2947
		if (IS_ERR_OR_NULL(em)) {
2948
			SetPageError(page);
2949 2950
			if (!parent_locked)
				unlock_extent(tree, cur, end);
2951 2952 2953 2954 2955 2956
			break;
		}
		extent_offset = cur - em->start;
		BUG_ON(extent_map_end(em) <= cur);
		BUG_ON(end < cur);

2957
		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2958
			this_bio_flag |= EXTENT_BIO_COMPRESSED;
2959 2960 2961
			extent_set_compress_type(&this_bio_flag,
						 em->compress_type);
		}
C
Chris Mason 已提交
2962

2963 2964
		iosize = min(extent_map_end(em) - cur, end - cur + 1);
		cur_end = min(extent_map_end(em) - 1, end);
2965
		iosize = ALIGN(iosize, blocksize);
C
Chris Mason 已提交
2966 2967 2968 2969 2970 2971 2972
		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;
		}
2973 2974
		bdev = em->bdev;
		block_start = em->block_start;
Y
Yan Zheng 已提交
2975 2976
		if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
			block_start = EXTENT_MAP_HOLE;
2977 2978 2979 2980 2981 2982
		free_extent_map(em);
		em = NULL;

		/* we've found a hole, just zero and go on */
		if (block_start == EXTENT_MAP_HOLE) {
			char *userpage;
2983 2984
			struct extent_state *cached = NULL;

2985
			userpage = kmap_atomic(page);
2986
			memset(userpage + pg_offset, 0, iosize);
2987
			flush_dcache_page(page);
2988
			kunmap_atomic(userpage);
2989 2990

			set_extent_uptodate(tree, cur, cur + iosize - 1,
2991 2992 2993
					    &cached, GFP_NOFS);
			unlock_extent_cached(tree, cur, cur + iosize - 1,
			                     &cached, GFP_NOFS);
2994
			cur = cur + iosize;
2995
			pg_offset += iosize;
2996 2997 2998
			continue;
		}
		/* the get_extent function already copied into the page */
2999 3000
		if (test_range_bit(tree, cur, cur_end,
				   EXTENT_UPTODATE, 1, NULL)) {
3001
			check_page_uptodate(tree, page);
3002 3003
			if (!parent_locked)
				unlock_extent(tree, cur, cur + iosize - 1);
3004
			cur = cur + iosize;
3005
			pg_offset += iosize;
3006 3007
			continue;
		}
3008 3009 3010 3011 3012
		/* we have an inline extent but it didn't get marked up
		 * to date.  Error out
		 */
		if (block_start == EXTENT_MAP_INLINE) {
			SetPageError(page);
3013 3014
			if (!parent_locked)
				unlock_extent(tree, cur, cur + iosize - 1);
3015
			cur = cur + iosize;
3016
			pg_offset += iosize;
3017 3018
			continue;
		}
3019

3020
		pnr -= page->index;
3021
		ret = submit_extent_page(rw, tree, page,
3022
					 sector, disk_io_size, pg_offset,
3023
					 bdev, bio, pnr,
C
Chris Mason 已提交
3024 3025 3026
					 end_bio_extent_readpage, mirror_num,
					 *bio_flags,
					 this_bio_flag);
3027 3028 3029 3030
		if (!ret) {
			nr++;
			*bio_flags = this_bio_flag;
		} else {
3031
			SetPageError(page);
3032 3033
			if (!parent_locked)
				unlock_extent(tree, cur, cur + iosize - 1);
3034
		}
3035
		cur = cur + iosize;
3036
		pg_offset += iosize;
3037
	}
D
Dan Magenheimer 已提交
3038
out:
3039 3040 3041 3042 3043 3044 3045 3046
	if (!nr) {
		if (!PageError(page))
			SetPageUptodate(page);
		unlock_page(page);
	}
	return 0;
}

3047 3048 3049 3050
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,
3051
					     struct extent_map **em_cached,
3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 3071
					     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++) {
3072 3073
		__do_readpage(tree, pages[index], get_extent, em_cached, bio,
			      mirror_num, bio_flags, rw);
3074 3075 3076 3077 3078 3079 3080
		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,
3081
			       struct extent_map **em_cached,
3082 3083 3084
			       struct bio **bio, int mirror_num,
			       unsigned long *bio_flags, int rw)
{
3085
	u64 start = 0;
3086 3087 3088
	u64 end = 0;
	u64 page_start;
	int index;
3089
	int first_index = 0;
3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101

	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,
3102 3103 3104
						  end, get_extent, em_cached,
						  bio, mirror_num, bio_flags,
						  rw);
3105 3106 3107 3108 3109 3110 3111 3112 3113
			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,
3114
					  end, get_extent, em_cached, bio,
3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139
					  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);
	}

3140 3141
	ret = __do_readpage(tree, page, get_extent, NULL, bio, mirror_num,
			    bio_flags, rw);
3142 3143 3144
	return ret;
}

3145
int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
3146
			    get_extent_t *get_extent, int mirror_num)
3147 3148
{
	struct bio *bio = NULL;
C
Chris Mason 已提交
3149
	unsigned long bio_flags = 0;
3150 3151
	int ret;

3152
	ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
3153
				      &bio_flags, READ);
3154
	if (bio)
3155
		ret = submit_one_bio(READ, bio, mirror_num, bio_flags);
3156 3157 3158
	return ret;
}

3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172
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;
}

3173 3174 3175 3176 3177 3178 3179 3180 3181 3182
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;
}

3183
/*
3184 3185 3186 3187 3188 3189 3190 3191
 * 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)
3192
 */
3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288
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,
					       128 * 1024 * 1024);
		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)
3289 3290
{
	struct extent_io_tree *tree = epd->tree;
M
Miao Xie 已提交
3291
	u64 start = page_offset(page);
3292 3293 3294 3295 3296 3297 3298
	u64 page_end = start + PAGE_CACHE_SIZE - 1;
	u64 end;
	u64 cur = start;
	u64 extent_offset;
	u64 block_start;
	u64 iosize;
	sector_t sector;
3299
	struct extent_state *cached_state = NULL;
3300 3301
	struct extent_map *em;
	struct block_device *bdev;
3302
	size_t pg_offset = 0;
3303
	size_t blocksize;
3304 3305 3306
	int ret = 0;
	int nr = 0;
	bool compressed;
C
Chris Mason 已提交
3307

3308
	if (tree->ops && tree->ops->writepage_start_hook) {
C
Chris Mason 已提交
3309 3310
		ret = tree->ops->writepage_start_hook(page, start,
						      page_end);
3311 3312 3313 3314 3315 3316
		if (ret) {
			/* Fixup worker will requeue */
			if (ret == -EBUSY)
				wbc->pages_skipped++;
			else
				redirty_page_for_writepage(wbc, page);
3317

3318
			update_nr_written(page, wbc, nr_written);
3319
			unlock_page(page);
3320
			ret = 1;
3321
			goto done_unlocked;
3322 3323 3324
		}
	}

3325 3326 3327 3328 3329
	/*
	 * 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);
3330

3331
	end = page_end;
3332
	if (i_size <= start) {
3333 3334 3335
		if (tree->ops && tree->ops->writepage_end_io_hook)
			tree->ops->writepage_end_io_hook(page, start,
							 page_end, NULL, 1);
3336 3337 3338 3339 3340 3341
		goto done;
	}

	blocksize = inode->i_sb->s_blocksize;

	while (cur <= end) {
3342 3343
		u64 em_end;
		if (cur >= i_size) {
3344 3345 3346
			if (tree->ops && tree->ops->writepage_end_io_hook)
				tree->ops->writepage_end_io_hook(page, cur,
							 page_end, NULL, 1);
3347 3348
			break;
		}
3349
		em = epd->get_extent(inode, page, pg_offset, cur,
3350
				     end - cur + 1, 1);
3351
		if (IS_ERR_OR_NULL(em)) {
3352
			SetPageError(page);
3353
			ret = PTR_ERR_OR_ZERO(em);
3354 3355 3356 3357
			break;
		}

		extent_offset = cur - em->start;
3358 3359
		em_end = extent_map_end(em);
		BUG_ON(em_end <= cur);
3360
		BUG_ON(end < cur);
3361
		iosize = min(em_end - cur, end - cur + 1);
3362
		iosize = ALIGN(iosize, blocksize);
3363 3364 3365
		sector = (em->block_start + extent_offset) >> 9;
		bdev = em->bdev;
		block_start = em->block_start;
C
Chris Mason 已提交
3366
		compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
3367 3368 3369
		free_extent_map(em);
		em = NULL;

C
Chris Mason 已提交
3370 3371 3372 3373 3374
		/*
		 * compressed and inline extents are written through other
		 * paths in the FS
		 */
		if (compressed || block_start == EXTENT_MAP_HOLE ||
3375
		    block_start == EXTENT_MAP_INLINE) {
C
Chris Mason 已提交
3376 3377 3378 3379 3380 3381
			/*
			 * end_io notification does not happen here for
			 * compressed extents
			 */
			if (!compressed && tree->ops &&
			    tree->ops->writepage_end_io_hook)
3382 3383 3384
				tree->ops->writepage_end_io_hook(page, cur,
							 cur + iosize - 1,
							 NULL, 1);
C
Chris Mason 已提交
3385 3386 3387 3388 3389 3390 3391 3392 3393
			else if (compressed) {
				/* we don't want to end_page_writeback on
				 * a compressed extent.  this happens
				 * elsewhere
				 */
				nr++;
			}

			cur += iosize;
3394
			pg_offset += iosize;
3395 3396
			continue;
		}
C
Chris Mason 已提交
3397

3398 3399 3400 3401 3402 3403
		if (tree->ops && tree->ops->writepage_io_hook) {
			ret = tree->ops->writepage_io_hook(page, cur,
						cur + iosize - 1);
		} else {
			ret = 0;
		}
3404
		if (ret) {
3405
			SetPageError(page);
3406
		} else {
3407
			unsigned long max_nr = (i_size >> PAGE_CACHE_SHIFT) + 1;
3408

3409 3410
			set_range_writeback(tree, cur, cur + iosize - 1);
			if (!PageWriteback(page)) {
3411 3412
				btrfs_err(BTRFS_I(inode)->root->fs_info,
					   "page %lu not writeback, cur %llu end %llu",
3413
				       page->index, cur, end);
3414 3415
			}

3416 3417 3418
			ret = submit_extent_page(write_flags, tree, page,
						 sector, iosize, pg_offset,
						 bdev, &epd->bio, max_nr,
C
Chris Mason 已提交
3419 3420
						 end_bio_extent_writepage,
						 0, 0, 0);
3421 3422 3423 3424
			if (ret)
				SetPageError(page);
		}
		cur = cur + iosize;
3425
		pg_offset += iosize;
3426 3427
		nr++;
	}
3428 3429 3430 3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448 3449 3450 3451 3452 3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502
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;

3503 3504 3505 3506 3507 3508
done:
	if (nr == 0) {
		/* make sure the mapping tag for page dirty gets cleared */
		set_page_writeback(page);
		end_page_writeback(page);
	}
3509 3510 3511 3512
	if (PageError(page)) {
		ret = ret < 0 ? ret : -EIO;
		end_extent_writepage(page, ret, start, page_end);
	}
3513
	unlock_page(page);
3514
	return ret;
3515

3516
done_unlocked:
3517 3518 3519
	return 0;
}

3520
void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
3521
{
3522 3523
	wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
		       TASK_UNINTERRUPTIBLE);
3524 3525
}

3526 3527 3528 3529
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)
3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548
{
	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
3549 3550 3551 3552 3553
		while (1) {
			wait_on_extent_buffer_writeback(eb);
			btrfs_tree_lock(eb);
			if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
				break;
3554 3555 3556 3557
			btrfs_tree_unlock(eb);
		}
	}

3558 3559 3560 3561 3562 3563
	/*
	 * 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);
3564 3565
	if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
		set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3566
		spin_unlock(&eb->refs_lock);
3567
		btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3568 3569 3570
		__percpu_counter_add(&fs_info->dirty_metadata_bytes,
				     -eb->len,
				     fs_info->dirty_metadata_batch);
3571
		ret = 1;
3572 3573
	} else {
		spin_unlock(&eb->refs_lock);
3574 3575 3576 3577 3578 3579 3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590 3591 3592 3593 3594 3595 3596 3597 3598 3599
	}

	btrfs_tree_unlock(eb);

	if (!ret)
		return ret;

	num_pages = num_extent_pages(eb->start, eb->len);
	for (i = 0; i < num_pages; i++) {
		struct page *p = extent_buffer_page(eb, i);

		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);
3600
	smp_mb__after_atomic();
3601 3602 3603 3604 3605
	wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
}

static void end_bio_extent_buffer_writepage(struct bio *bio, int err)
{
3606
	struct bio_vec *bvec;
3607
	struct extent_buffer *eb;
3608
	int i, done;
3609

3610
	bio_for_each_segment_all(bvec, bio, i) {
3611 3612 3613 3614 3615 3616
		struct page *page = bvec->bv_page;

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

3617
		if (err || test_bit(EXTENT_BUFFER_IOERR, &eb->bflags)) {
3618 3619 3620 3621 3622 3623 3624 3625 3626 3627 3628
			set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
			ClearPageUptodate(page);
			SetPageError(page);
		}

		end_page_writeback(page);

		if (!done)
			continue;

		end_extent_buffer_writeback(eb);
3629
	}
3630 3631 3632 3633

	bio_put(bio);
}

3634
static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
3635 3636 3637 3638 3639
			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;
3640
	struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
3641 3642
	u64 offset = eb->start;
	unsigned long i, num_pages;
3643
	unsigned long bio_flags = 0;
3644
	int rw = (epd->sync_io ? WRITE_SYNC : WRITE) | REQ_META;
3645
	int ret = 0;
3646 3647 3648 3649

	clear_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
	num_pages = num_extent_pages(eb->start, eb->len);
	atomic_set(&eb->io_pages, num_pages);
3650 3651 3652
	if (btrfs_header_owner(eb) == BTRFS_TREE_LOG_OBJECTID)
		bio_flags = EXTENT_BIO_TREE_LOG;

3653 3654 3655 3656 3657
	for (i = 0; i < num_pages; i++) {
		struct page *p = extent_buffer_page(eb, i);

		clear_page_dirty_for_io(p);
		set_page_writeback(p);
3658
		ret = submit_extent_page(rw, tree, p, offset >> 9,
3659 3660
					 PAGE_CACHE_SIZE, 0, bdev, &epd->bio,
					 -1, end_bio_extent_buffer_writepage,
3661 3662
					 0, epd->bio_flags, bio_flags);
		epd->bio_flags = bio_flags;
3663 3664 3665
		if (ret) {
			set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
			SetPageError(p);
3666
			end_page_writeback(p);
3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679
			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++) {
			struct page *p = extent_buffer_page(eb, i);
3680
			clear_page_dirty_for_io(p);
3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691 3692 3693 3694 3695 3696 3697 3698
			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,
3699
		.bio_flags = 0,
3700 3701 3702 3703 3704 3705 3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728 3729 3730 3731 3732 3733 3734 3735 3736 3737 3738 3739 3740 3741 3742 3743
	};
	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;
			}

3744 3745 3746 3747 3748 3749
			spin_lock(&mapping->private_lock);
			if (!PagePrivate(page)) {
				spin_unlock(&mapping->private_lock);
				continue;
			}

3750
			eb = (struct extent_buffer *)page->private;
3751 3752 3753 3754 3755 3756

			/*
			 * 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.
			 */
3757
			if (WARN_ON(!eb)) {
3758
				spin_unlock(&mapping->private_lock);
3759 3760 3761
				continue;
			}

3762 3763
			if (eb == prev_eb) {
				spin_unlock(&mapping->private_lock);
3764
				continue;
3765
			}
3766

3767 3768 3769
			ret = atomic_inc_not_zero(&eb->refs);
			spin_unlock(&mapping->private_lock);
			if (!ret)
3770 3771 3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803 3804 3805 3806 3807 3808 3809
				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;
}

3810
/**
C
Chris Mason 已提交
3811
 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
3812 3813 3814 3815 3816 3817 3818 3819 3820 3821 3822 3823 3824
 * @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.
 */
3825
static int extent_write_cache_pages(struct extent_io_tree *tree,
C
Chris Mason 已提交
3826 3827
			     struct address_space *mapping,
			     struct writeback_control *wbc,
C
Chris Mason 已提交
3828 3829
			     writepage_t writepage, void *data,
			     void (*flush_fn)(void *))
3830
{
3831
	struct inode *inode = mapping->host;
3832 3833
	int ret = 0;
	int done = 0;
3834
	int err = 0;
3835
	int nr_to_write_done = 0;
3836 3837 3838 3839 3840
	struct pagevec pvec;
	int nr_pages;
	pgoff_t index;
	pgoff_t end;		/* Inclusive */
	int scanned = 0;
3841
	int tag;
3842

3843 3844 3845 3846 3847 3848 3849 3850 3851 3852 3853 3854
	/*
	 * 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;

3855 3856 3857 3858 3859 3860 3861 3862 3863
	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;
	}
3864 3865 3866 3867
	if (wbc->sync_mode == WB_SYNC_ALL)
		tag = PAGECACHE_TAG_TOWRITE;
	else
		tag = PAGECACHE_TAG_DIRTY;
3868
retry:
3869 3870
	if (wbc->sync_mode == WB_SYNC_ALL)
		tag_pages_for_writeback(mapping, index, end);
3871
	while (!done && !nr_to_write_done && (index <= end) &&
3872 3873
	       (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
			min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
3874 3875 3876 3877 3878 3879 3880 3881 3882 3883 3884 3885 3886
		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
			 */
3887 3888 3889
			if (!trylock_page(page)) {
				flush_fn(data);
				lock_page(page);
3890
			}
3891 3892 3893 3894 3895 3896 3897 3898 3899 3900 3901 3902

			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
3903
			if (wbc->sync_mode != WB_SYNC_NONE) {
3904 3905
				if (PageWriteback(page))
					flush_fn(data);
3906
				wait_on_page_writeback(page);
C
Chris Mason 已提交
3907
			}
3908 3909 3910 3911 3912 3913 3914 3915 3916 3917 3918 3919 3920

			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;
			}
3921 3922
			if (!err && ret < 0)
				err = ret;
3923 3924 3925 3926 3927 3928 3929

			/*
			 * 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;
3930 3931 3932 3933
		}
		pagevec_release(&pvec);
		cond_resched();
	}
3934
	if (!scanned && !done && !err) {
3935 3936 3937 3938 3939 3940 3941 3942
		/*
		 * 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;
	}
3943
	btrfs_add_delayed_iput(inode);
3944
	return err;
3945 3946
}

3947
static void flush_epd_write_bio(struct extent_page_data *epd)
C
Chris Mason 已提交
3948 3949
{
	if (epd->bio) {
3950 3951 3952
		int rw = WRITE;
		int ret;

3953
		if (epd->sync_io)
3954 3955
			rw = WRITE_SYNC;

3956
		ret = submit_one_bio(rw, epd->bio, 0, epd->bio_flags);
3957
		BUG_ON(ret < 0); /* -ENOMEM */
C
Chris Mason 已提交
3958 3959 3960 3961
		epd->bio = NULL;
	}
}

3962 3963 3964 3965 3966 3967
static noinline void flush_write_bio(void *data)
{
	struct extent_page_data *epd = data;
	flush_epd_write_bio(epd);
}

3968 3969 3970 3971 3972 3973 3974 3975 3976
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,
3977
		.extent_locked = 0,
3978
		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
3979
		.bio_flags = 0,
3980 3981 3982 3983
	};

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

3984
	flush_epd_write_bio(&epd);
3985 3986 3987
	return ret;
}

3988 3989 3990 3991 3992 3993 3994 3995 3996 3997 3998 3999 4000 4001 4002
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,
4003
		.sync_io = mode == WB_SYNC_ALL,
4004
		.bio_flags = 0,
4005 4006 4007 4008 4009 4010 4011 4012
	};
	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
4013
	while (start <= end) {
4014 4015 4016 4017 4018 4019 4020 4021 4022 4023 4024 4025 4026 4027
		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;
	}

4028
	flush_epd_write_bio(&epd);
4029 4030
	return ret;
}
4031 4032 4033 4034 4035 4036 4037 4038 4039 4040 4041

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,
4042
		.extent_locked = 0,
4043
		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
4044
		.bio_flags = 0,
4045 4046
	};

C
Chris Mason 已提交
4047
	ret = extent_write_cache_pages(tree, mapping, wbc,
C
Chris Mason 已提交
4048 4049
				       __extent_writepage, &epd,
				       flush_write_bio);
4050
	flush_epd_write_bio(&epd);
4051 4052 4053 4054 4055 4056 4057 4058 4059 4060
	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
4061
	unsigned long bio_flags = 0;
L
Liu Bo 已提交
4062 4063
	struct page *pagepool[16];
	struct page *page;
4064
	struct extent_map *em_cached = NULL;
L
Liu Bo 已提交
4065
	int nr = 0;
4066 4067

	for (page_idx = 0; page_idx < nr_pages; page_idx++) {
L
Liu Bo 已提交
4068
		page = list_entry(pages->prev, struct page, lru);
4069 4070 4071

		prefetchw(&page->flags);
		list_del(&page->lru);
L
Liu Bo 已提交
4072
		if (add_to_page_cache_lru(page, mapping,
4073
					page->index, GFP_NOFS)) {
L
Liu Bo 已提交
4074 4075
			page_cache_release(page);
			continue;
4076
		}
L
Liu Bo 已提交
4077 4078 4079 4080

		pagepool[nr++] = page;
		if (nr < ARRAY_SIZE(pagepool))
			continue;
4081
		__extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
4082
				   &bio, 0, &bio_flags, READ);
L
Liu Bo 已提交
4083
		nr = 0;
4084
	}
4085
	if (nr)
4086
		__extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
4087
				   &bio, 0, &bio_flags, READ);
L
Liu Bo 已提交
4088

4089 4090 4091
	if (em_cached)
		free_extent_map(em_cached);

4092 4093
	BUG_ON(!list_empty(pages));
	if (bio)
4094
		return submit_one_bio(READ, bio, 0, bio_flags);
4095 4096 4097 4098 4099 4100 4101 4102 4103 4104 4105
	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)
{
4106
	struct extent_state *cached_state = NULL;
M
Miao Xie 已提交
4107
	u64 start = page_offset(page);
4108 4109 4110
	u64 end = start + PAGE_CACHE_SIZE - 1;
	size_t blocksize = page->mapping->host->i_sb->s_blocksize;

4111
	start += ALIGN(offset, blocksize);
4112 4113 4114
	if (start > end)
		return 0;

4115
	lock_extent_bits(tree, start, end, 0, &cached_state);
4116
	wait_on_page_writeback(page);
4117
	clear_extent_bit(tree, start, end,
4118 4119
			 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
			 EXTENT_DO_ACCOUNTING,
4120
			 1, 1, &cached_state, GFP_NOFS);
4121 4122 4123
	return 0;
}

4124 4125 4126 4127 4128
/*
 * 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.
 */
4129 4130 4131
static int try_release_extent_state(struct extent_map_tree *map,
				    struct extent_io_tree *tree,
				    struct page *page, gfp_t mask)
4132
{
M
Miao Xie 已提交
4133
	u64 start = page_offset(page);
4134 4135 4136
	u64 end = start + PAGE_CACHE_SIZE - 1;
	int ret = 1;

4137
	if (test_range_bit(tree, start, end,
4138
			   EXTENT_IOBITS, 0, NULL))
4139 4140 4141 4142
		ret = 0;
	else {
		if ((mask & GFP_NOFS) == GFP_NOFS)
			mask = GFP_NOFS;
4143 4144 4145 4146
		/*
		 * at this point we can safely clear everything except the
		 * locked bit and the nodatasum bit
		 */
4147
		ret = clear_extent_bit(tree, start, end,
4148 4149
				 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
				 0, 0, NULL, mask);
4150 4151 4152 4153 4154 4155 4156 4157

		/* if clear_extent_bit failed for enomem reasons,
		 * we can't allow the release to continue.
		 */
		if (ret < 0)
			ret = 0;
		else
			ret = 1;
4158 4159 4160 4161
	}
	return ret;
}

4162 4163 4164 4165 4166 4167
/*
 * 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,
4168 4169
			       struct extent_io_tree *tree, struct page *page,
			       gfp_t mask)
4170 4171
{
	struct extent_map *em;
M
Miao Xie 已提交
4172
	u64 start = page_offset(page);
4173
	u64 end = start + PAGE_CACHE_SIZE - 1;
4174

4175 4176
	if ((mask & __GFP_WAIT) &&
	    page->mapping->host->i_size > 16 * 1024 * 1024) {
4177
		u64 len;
4178
		while (start <= end) {
4179
			len = end - start + 1;
4180
			write_lock(&map->lock);
4181
			em = lookup_extent_mapping(map, start, len);
4182
			if (!em) {
4183
				write_unlock(&map->lock);
4184 4185
				break;
			}
4186 4187
			if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
			    em->start != start) {
4188
				write_unlock(&map->lock);
4189 4190 4191 4192 4193
				free_extent_map(em);
				break;
			}
			if (!test_range_bit(tree, em->start,
					    extent_map_end(em) - 1,
4194
					    EXTENT_LOCKED | EXTENT_WRITEBACK,
4195
					    0, NULL)) {
4196 4197 4198 4199 4200
				remove_extent_mapping(map, em);
				/* once for the rb tree */
				free_extent_map(em);
			}
			start = extent_map_end(em);
4201
			write_unlock(&map->lock);
4202 4203

			/* once for us */
4204 4205 4206
			free_extent_map(em);
		}
	}
4207
	return try_release_extent_state(map, tree, page, mask);
4208 4209
}

4210 4211 4212 4213 4214 4215 4216 4217 4218 4219 4220 4221 4222 4223 4224 4225
/*
 * 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;

4226
	while (1) {
4227 4228 4229
		len = last - offset;
		if (len == 0)
			break;
4230
		len = ALIGN(len, sectorsize);
4231
		em = get_extent(inode, NULL, 0, offset, len, 0);
4232
		if (IS_ERR_OR_NULL(em))
4233 4234 4235 4236 4237 4238 4239 4240 4241 4242 4243 4244 4245 4246 4247 4248 4249
			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
4250 4251 4252
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
4253
	int ret = 0;
Y
Yehuda Sadeh 已提交
4254 4255 4256
	u64 off = start;
	u64 max = start + len;
	u32 flags = 0;
J
Josef Bacik 已提交
4257 4258
	u32 found_type;
	u64 last;
4259
	u64 last_for_get_extent = 0;
Y
Yehuda Sadeh 已提交
4260
	u64 disko = 0;
4261
	u64 isize = i_size_read(inode);
J
Josef Bacik 已提交
4262
	struct btrfs_key found_key;
Y
Yehuda Sadeh 已提交
4263
	struct extent_map *em = NULL;
4264
	struct extent_state *cached_state = NULL;
J
Josef Bacik 已提交
4265
	struct btrfs_path *path;
4266
	struct btrfs_root *root = BTRFS_I(inode)->root;
Y
Yehuda Sadeh 已提交
4267
	int end = 0;
4268 4269 4270
	u64 em_start = 0;
	u64 em_len = 0;
	u64 em_end = 0;
Y
Yehuda Sadeh 已提交
4271 4272 4273 4274

	if (len == 0)
		return -EINVAL;

J
Josef Bacik 已提交
4275 4276 4277 4278 4279
	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
	path->leave_spinning = 1;

4280 4281
	start = round_down(start, BTRFS_I(inode)->root->sectorsize);
	len = round_up(max, BTRFS_I(inode)->root->sectorsize) - start;
4282

4283 4284 4285 4286
	/*
	 * lookup the last file extent.  We're not using i_size here
	 * because there might be preallocation past i_size
	 */
4287 4288
	ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode), -1,
				       0);
J
Josef Bacik 已提交
4289 4290 4291 4292 4293 4294 4295
	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]);
4296
	found_type = found_key.type;
J
Josef Bacik 已提交
4297

4298
	/* No extents, but there might be delalloc bits */
L
Li Zefan 已提交
4299
	if (found_key.objectid != btrfs_ino(inode) ||
J
Josef Bacik 已提交
4300
	    found_type != BTRFS_EXTENT_DATA_KEY) {
4301 4302 4303 4304 4305 4306 4307 4308 4309 4310 4311
		/* 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
4312
	}
4313
	btrfs_release_path(path);
J
Josef Bacik 已提交
4314

4315 4316 4317 4318 4319 4320 4321 4322 4323 4324
	/*
	 * 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
4325
	lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len - 1, 0,
4326
			 &cached_state);
4327

4328
	em = get_extent_skip_holes(inode, start, last_for_get_extent,
4329
				   get_extent);
Y
Yehuda Sadeh 已提交
4330 4331 4332 4333 4334 4335
	if (!em)
		goto out;
	if (IS_ERR(em)) {
		ret = PTR_ERR(em);
		goto out;
	}
J
Josef Bacik 已提交
4336

Y
Yehuda Sadeh 已提交
4337
	while (!end) {
4338
		u64 offset_in_extent = 0;
4339 4340 4341 4342 4343 4344 4345 4346 4347 4348 4349 4350

		/* 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
4351

4352 4353
		/*
		 * record the offset from the start of the extent
4354 4355 4356
		 * 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.
4357
		 */
4358 4359
		if (!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
			offset_in_extent = em_start - em->start;
4360
		em_end = extent_map_end(em);
4361
		em_len = em_end - em_start;
Y
Yehuda Sadeh 已提交
4362 4363 4364
		disko = 0;
		flags = 0;

4365 4366 4367 4368 4369 4370 4371
		/*
		 * bump off for our next call to get_extent
		 */
		off = extent_map_end(em);
		if (off >= max)
			end = 1;

4372
		if (em->block_start == EXTENT_MAP_LAST_BYTE) {
Y
Yehuda Sadeh 已提交
4373 4374
			end = 1;
			flags |= FIEMAP_EXTENT_LAST;
4375
		} else if (em->block_start == EXTENT_MAP_INLINE) {
Y
Yehuda Sadeh 已提交
4376 4377
			flags |= (FIEMAP_EXTENT_DATA_INLINE |
				  FIEMAP_EXTENT_NOT_ALIGNED);
4378
		} else if (em->block_start == EXTENT_MAP_DELALLOC) {
Y
Yehuda Sadeh 已提交
4379 4380
			flags |= (FIEMAP_EXTENT_DELALLOC |
				  FIEMAP_EXTENT_UNKNOWN);
4381 4382 4383
		} else if (fieinfo->fi_extents_max) {
			u64 bytenr = em->block_start -
				(em->start - em->orig_start);
4384

4385
			disko = em->block_start + offset_in_extent;
4386 4387 4388 4389

			/*
			 * As btrfs supports shared space, this information
			 * can be exported to userspace tools via
4390 4391 4392
			 * flag FIEMAP_EXTENT_SHARED.  If fi_extents_max == 0
			 * then we're just getting a count and we can skip the
			 * lookup stuff.
4393
			 */
4394 4395 4396 4397
			ret = btrfs_check_shared(NULL, root->fs_info,
						 root->objectid,
						 btrfs_ino(inode), bytenr);
			if (ret < 0)
4398
				goto out_free;
4399
			if (ret)
4400
				flags |= FIEMAP_EXTENT_SHARED;
4401
			ret = 0;
Y
Yehuda Sadeh 已提交
4402 4403 4404 4405 4406 4407
		}
		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
			flags |= FIEMAP_EXTENT_ENCODED;

		free_extent_map(em);
		em = NULL;
4408 4409
		if ((em_start >= last) || em_len == (u64)-1 ||
		   (last == (u64)-1 && isize <= em_end)) {
Y
Yehuda Sadeh 已提交
4410 4411 4412 4413
			flags |= FIEMAP_EXTENT_LAST;
			end = 1;
		}

4414 4415 4416 4417 4418 4419 4420 4421
		/* 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
4422 4423 4424
			flags |= FIEMAP_EXTENT_LAST;
			end = 1;
		}
4425 4426 4427 4428
		ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
					      em_len, flags);
		if (ret)
			goto out_free;
Y
Yehuda Sadeh 已提交
4429 4430 4431 4432
	}
out_free:
	free_extent_map(em);
out:
4433
	btrfs_free_path(path);
L
Liu Bo 已提交
4434
	unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4435
			     &cached_state, GFP_NOFS);
Y
Yehuda Sadeh 已提交
4436 4437 4438
	return ret;
}

4439 4440
static void __free_extent_buffer(struct extent_buffer *eb)
{
4441
	btrfs_leak_debug_del(&eb->leak_list);
4442 4443 4444
	kmem_cache_free(extent_buffer_cache, eb);
}

4445
int extent_buffer_under_io(struct extent_buffer *eb)
4446 4447 4448 4449 4450 4451 4452 4453 4454 4455 4456 4457 4458 4459 4460 4461 4462 4463 4464 4465 4466 4467 4468 4469 4470 4471 4472 4473 4474 4475 4476 4477 4478 4479 4480 4481 4482 4483 4484 4485 4486 4487 4488 4489 4490 4491 4492 4493 4494 4495 4496 4497 4498 4499 4500 4501 4502 4503 4504 4505 4506 4507 4508 4509 4510 4511 4512 4513 4514
{
	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.
 */
static void btrfs_release_extent_buffer_page(struct extent_buffer *eb,
						unsigned long start_idx)
{
	unsigned long index;
	unsigned long num_pages;
	struct page *page;
	int mapped = !test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);

	BUG_ON(extent_buffer_under_io(eb));

	num_pages = num_extent_pages(eb->start, eb->len);
	index = start_idx + num_pages;
	if (start_idx >= index)
		return;

	do {
		index--;
		page = extent_buffer_page(eb, index);
		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);
		}
	} while (index != start_idx);
}

/*
 * Helper for releasing the extent buffer.
 */
static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
{
	btrfs_release_extent_buffer_page(eb, 0);
	__free_extent_buffer(eb);
}

4515 4516 4517
static struct extent_buffer *
__alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
		      unsigned long len, gfp_t mask)
4518 4519 4520 4521
{
	struct extent_buffer *eb = NULL;

	eb = kmem_cache_zalloc(extent_buffer_cache, mask);
T
Tsutomu Itoh 已提交
4522 4523
	if (eb == NULL)
		return NULL;
4524 4525
	eb->start = start;
	eb->len = len;
4526
	eb->fs_info = fs_info;
4527
	eb->bflags = 0;
4528 4529 4530 4531 4532 4533 4534
	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);
4535
	eb->lock_nested = 0;
4536 4537
	init_waitqueue_head(&eb->write_lock_wq);
	init_waitqueue_head(&eb->read_lock_wq);
4538

4539 4540
	btrfs_leak_debug_add(&eb->leak_list, &buffers);

4541
	spin_lock_init(&eb->refs_lock);
4542
	atomic_set(&eb->refs, 1);
4543
	atomic_set(&eb->io_pages, 0);
4544

4545 4546 4547 4548 4549 4550
	/*
	 * 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);
4551 4552 4553 4554

	return eb;
}

4555 4556 4557 4558 4559 4560 4561
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);

4562
	new = __alloc_extent_buffer(NULL, src->start, src->len, GFP_NOFS);
4563 4564 4565 4566
	if (new == NULL)
		return NULL;

	for (i = 0; i < num_pages; i++) {
4567
		p = alloc_page(GFP_NOFS);
4568 4569 4570 4571
		if (!p) {
			btrfs_release_extent_buffer(new);
			return NULL;
		}
4572 4573 4574 4575 4576 4577 4578 4579 4580 4581 4582 4583 4584 4585 4586 4587 4588 4589 4590
		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;
}

struct extent_buffer *alloc_dummy_extent_buffer(u64 start, unsigned long len)
{
	struct extent_buffer *eb;
	unsigned long num_pages = num_extent_pages(0, len);
	unsigned long i;

4591
	eb = __alloc_extent_buffer(NULL, start, len, GFP_NOFS);
4592 4593 4594 4595
	if (!eb)
		return NULL;

	for (i = 0; i < num_pages; i++) {
4596
		eb->pages[i] = alloc_page(GFP_NOFS);
4597 4598 4599 4600 4601 4602 4603 4604 4605
		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:
4606 4607
	for (; i > 0; i--)
		__free_page(eb->pages[i - 1]);
4608 4609 4610 4611
	__free_extent_buffer(eb);
	return NULL;
}

4612 4613
static void check_buffer_tree_ref(struct extent_buffer *eb)
{
4614
	int refs;
4615 4616 4617 4618 4619 4620 4621 4622 4623 4624 4625 4626 4627 4628 4629 4630 4631 4632 4633 4634
	/* 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.
	 */
4635 4636 4637 4638
	refs = atomic_read(&eb->refs);
	if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
		return;

4639 4640
	spin_lock(&eb->refs_lock);
	if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4641
		atomic_inc(&eb->refs);
4642
	spin_unlock(&eb->refs_lock);
4643 4644
}

4645 4646
static void mark_extent_buffer_accessed(struct extent_buffer *eb,
		struct page *accessed)
4647 4648 4649
{
	unsigned long num_pages, i;

4650 4651
	check_buffer_tree_ref(eb);

4652 4653 4654
	num_pages = num_extent_pages(eb->start, eb->len);
	for (i = 0; i < num_pages; i++) {
		struct page *p = extent_buffer_page(eb, i);
4655 4656
		if (p != accessed)
			mark_page_accessed(p);
4657 4658 4659
	}
}

4660 4661
struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
					 u64 start)
4662 4663 4664 4665
{
	struct extent_buffer *eb;

	rcu_read_lock();
4666 4667
	eb = radix_tree_lookup(&fs_info->buffer_radix,
			       start >> PAGE_CACHE_SHIFT);
4668 4669
	if (eb && atomic_inc_not_zero(&eb->refs)) {
		rcu_read_unlock();
4670
		mark_extent_buffer_accessed(eb, NULL);
4671 4672 4673 4674 4675 4676 4677
		return eb;
	}
	rcu_read_unlock();

	return NULL;
}

4678 4679 4680 4681 4682 4683 4684 4685 4686 4687 4688 4689 4690 4691 4692 4693 4694 4695 4696 4697 4698 4699 4700 4701 4702 4703 4704 4705 4706 4707 4708 4709 4710 4711 4712 4713 4714 4715 4716 4717 4718 4719 4720 4721 4722 4723 4724
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
					       u64 start, unsigned long len)
{
	struct extent_buffer *eb, *exists = NULL;
	int ret;

	eb = find_extent_buffer(fs_info, start);
	if (eb)
		return eb;
	eb = alloc_dummy_extent_buffer(start, len);
	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

4725
struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
4726
					  u64 start, unsigned long len)
4727 4728 4729 4730 4731
{
	unsigned long num_pages = num_extent_pages(start, len);
	unsigned long i;
	unsigned long index = start >> PAGE_CACHE_SHIFT;
	struct extent_buffer *eb;
4732
	struct extent_buffer *exists = NULL;
4733
	struct page *p;
4734
	struct address_space *mapping = fs_info->btree_inode->i_mapping;
4735
	int uptodate = 1;
4736
	int ret;
4737

4738
	eb = find_extent_buffer(fs_info, start);
4739
	if (eb)
4740 4741
		return eb;

4742
	eb = __alloc_extent_buffer(fs_info, start, len, GFP_NOFS);
4743
	if (!eb)
4744 4745
		return NULL;

4746
	for (i = 0; i < num_pages; i++, index++) {
4747
		p = find_or_create_page(mapping, index, GFP_NOFS);
4748
		if (!p)
4749
			goto free_eb;
J
Josef Bacik 已提交
4750 4751 4752 4753 4754 4755 4756 4757 4758 4759 4760 4761 4762 4763

		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);
4764
				page_cache_release(p);
4765
				mark_extent_buffer_accessed(exists, p);
J
Josef Bacik 已提交
4766 4767 4768
				goto free_eb;
			}

4769
			/*
J
Josef Bacik 已提交
4770 4771 4772 4773
			 * Do this so attach doesn't complain and we need to
			 * drop the ref the old guy had.
			 */
			ClearPagePrivate(p);
4774
			WARN_ON(PageDirty(p));
J
Josef Bacik 已提交
4775
			page_cache_release(p);
4776
		}
J
Josef Bacik 已提交
4777 4778
		attach_extent_buffer_page(eb, p);
		spin_unlock(&mapping->private_lock);
4779
		WARN_ON(PageDirty(p));
4780
		eb->pages[i] = p;
4781 4782
		if (!PageUptodate(p))
			uptodate = 0;
C
Chris Mason 已提交
4783 4784 4785 4786 4787

		/*
		 * see below about how we avoid a nasty race with release page
		 * and why we unlock later
		 */
4788 4789
	}
	if (uptodate)
4790
		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4791
again:
4792 4793 4794 4795
	ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
	if (ret)
		goto free_eb;

4796 4797 4798 4799
	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);
4800
	radix_tree_preload_end();
4801
	if (ret == -EEXIST) {
4802
		exists = find_extent_buffer(fs_info, start);
4803 4804 4805
		if (exists)
			goto free_eb;
		else
4806
			goto again;
4807 4808
	}
	/* add one reference for the tree */
4809
	check_buffer_tree_ref(eb);
4810
	set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
C
Chris Mason 已提交
4811 4812 4813 4814 4815 4816 4817 4818 4819 4820

	/*
	 * 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
	 */
4821 4822 4823 4824 4825 4826 4827
	SetPageChecked(eb->pages[0]);
	for (i = 1; i < num_pages; i++) {
		p = extent_buffer_page(eb, i);
		ClearPageChecked(p);
		unlock_page(p);
	}
	unlock_page(eb->pages[0]);
4828 4829
	return eb;

4830
free_eb:
4831 4832 4833 4834
	for (i = 0; i < num_pages; i++) {
		if (eb->pages[i])
			unlock_page(eb->pages[i]);
	}
C
Chris Mason 已提交
4835

4836
	WARN_ON(!atomic_dec_and_test(&eb->refs));
4837
	btrfs_release_extent_buffer(eb);
4838
	return exists;
4839 4840
}

4841 4842 4843 4844 4845 4846 4847 4848 4849
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 */
4850
static int release_extent_buffer(struct extent_buffer *eb)
4851 4852 4853
{
	WARN_ON(atomic_read(&eb->refs) == 0);
	if (atomic_dec_and_test(&eb->refs)) {
4854
		if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
4855
			struct btrfs_fs_info *fs_info = eb->fs_info;
4856

4857
			spin_unlock(&eb->refs_lock);
4858

4859 4860
			spin_lock(&fs_info->buffer_lock);
			radix_tree_delete(&fs_info->buffer_radix,
4861
					  eb->start >> PAGE_CACHE_SHIFT);
4862
			spin_unlock(&fs_info->buffer_lock);
4863 4864
		} else {
			spin_unlock(&eb->refs_lock);
4865
		}
4866 4867 4868 4869

		/* Should be safe to release our pages at this point */
		btrfs_release_extent_buffer_page(eb, 0);
		call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
4870
		return 1;
4871 4872
	}
	spin_unlock(&eb->refs_lock);
4873 4874

	return 0;
4875 4876
}

4877 4878
void free_extent_buffer(struct extent_buffer *eb)
{
4879 4880
	int refs;
	int old;
4881 4882 4883
	if (!eb)
		return;

4884 4885 4886 4887 4888 4889 4890 4891 4892
	while (1) {
		refs = atomic_read(&eb->refs);
		if (refs <= 3)
			break;
		old = atomic_cmpxchg(&eb->refs, refs, refs - 1);
		if (old == refs)
			return;
	}

4893
	spin_lock(&eb->refs_lock);
4894 4895 4896 4897
	if (atomic_read(&eb->refs) == 2 &&
	    test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))
		atomic_dec(&eb->refs);

4898 4899
	if (atomic_read(&eb->refs) == 2 &&
	    test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
4900
	    !extent_buffer_under_io(eb) &&
4901 4902 4903 4904 4905 4906 4907
	    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.
	 */
4908
	release_extent_buffer(eb);
4909 4910 4911 4912 4913
}

void free_extent_buffer_stale(struct extent_buffer *eb)
{
	if (!eb)
4914 4915
		return;

4916 4917 4918
	spin_lock(&eb->refs_lock);
	set_bit(EXTENT_BUFFER_STALE, &eb->bflags);

4919
	if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
4920 4921
	    test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
		atomic_dec(&eb->refs);
4922
	release_extent_buffer(eb);
4923 4924
}

4925
void clear_extent_buffer_dirty(struct extent_buffer *eb)
4926 4927 4928 4929 4930 4931 4932 4933 4934
{
	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++) {
		page = extent_buffer_page(eb, i);
4935
		if (!PageDirty(page))
C
Chris Mason 已提交
4936 4937
			continue;

4938
		lock_page(page);
C
Chris Mason 已提交
4939 4940
		WARN_ON(!PagePrivate(page));

4941
		clear_page_dirty_for_io(page);
4942
		spin_lock_irq(&page->mapping->tree_lock);
4943 4944 4945 4946 4947
		if (!PageDirty(page)) {
			radix_tree_tag_clear(&page->mapping->page_tree,
						page_index(page),
						PAGECACHE_TAG_DIRTY);
		}
4948
		spin_unlock_irq(&page->mapping->tree_lock);
4949
		ClearPageError(page);
4950
		unlock_page(page);
4951
	}
4952
	WARN_ON(atomic_read(&eb->refs) == 0);
4953 4954
}

4955
int set_extent_buffer_dirty(struct extent_buffer *eb)
4956 4957 4958
{
	unsigned long i;
	unsigned long num_pages;
4959
	int was_dirty = 0;
4960

4961 4962
	check_buffer_tree_ref(eb);

4963
	was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
4964

4965
	num_pages = num_extent_pages(eb->start, eb->len);
4966
	WARN_ON(atomic_read(&eb->refs) == 0);
4967 4968
	WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));

4969
	for (i = 0; i < num_pages; i++)
4970
		set_page_dirty(extent_buffer_page(eb, i));
4971
	return was_dirty;
4972 4973
}

4974
int clear_extent_buffer_uptodate(struct extent_buffer *eb)
4975 4976 4977 4978 4979
{
	unsigned long i;
	struct page *page;
	unsigned long num_pages;

4980
	clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4981
	num_pages = num_extent_pages(eb->start, eb->len);
4982 4983
	for (i = 0; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
C
Chris Mason 已提交
4984 4985
		if (page)
			ClearPageUptodate(page);
4986 4987 4988 4989
	}
	return 0;
}

4990
int set_extent_buffer_uptodate(struct extent_buffer *eb)
4991 4992 4993 4994 4995
{
	unsigned long i;
	struct page *page;
	unsigned long num_pages;

4996
	set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4997 4998 4999 5000 5001 5002 5003 5004
	num_pages = num_extent_pages(eb->start, eb->len);
	for (i = 0; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
		SetPageUptodate(page);
	}
	return 0;
}

5005
int extent_buffer_uptodate(struct extent_buffer *eb)
5006
{
5007
	return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5008 5009 5010
}

int read_extent_buffer_pages(struct extent_io_tree *tree,
5011
			     struct extent_buffer *eb, u64 start, int wait,
5012
			     get_extent_t *get_extent, int mirror_num)
5013 5014 5015 5016 5017 5018
{
	unsigned long i;
	unsigned long start_i;
	struct page *page;
	int err;
	int ret = 0;
5019 5020
	int locked_pages = 0;
	int all_uptodate = 1;
5021
	unsigned long num_pages;
5022
	unsigned long num_reads = 0;
5023
	struct bio *bio = NULL;
C
Chris Mason 已提交
5024
	unsigned long bio_flags = 0;
5025

5026
	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
5027 5028 5029 5030 5031 5032 5033 5034 5035 5036 5037 5038 5039
		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++) {
		page = extent_buffer_page(eb, i);
5040
		if (wait == WAIT_NONE) {
5041
			if (!trylock_page(page))
5042
				goto unlock_exit;
5043 5044 5045
		} else {
			lock_page(page);
		}
5046
		locked_pages++;
5047 5048
		if (!PageUptodate(page)) {
			num_reads++;
5049
			all_uptodate = 0;
5050
		}
5051 5052 5053
	}
	if (all_uptodate) {
		if (start_i == 0)
5054
			set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
5055 5056 5057
		goto unlock_exit;
	}

5058
	clear_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
5059
	eb->read_mirror = 0;
5060
	atomic_set(&eb->io_pages, num_reads);
5061 5062 5063
	for (i = start_i; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
		if (!PageUptodate(page)) {
5064
			ClearPageError(page);
5065
			err = __extent_read_full_page(tree, page,
5066
						      get_extent, &bio,
5067 5068
						      mirror_num, &bio_flags,
						      READ | REQ_META);
C
Chris Mason 已提交
5069
			if (err)
5070 5071 5072 5073 5074 5075
				ret = err;
		} else {
			unlock_page(page);
		}
	}

5076
	if (bio) {
5077 5078
		err = submit_one_bio(READ | REQ_META, bio, mirror_num,
				     bio_flags);
5079 5080
		if (err)
			return err;
5081
	}
5082

5083
	if (ret || wait != WAIT_COMPLETE)
5084
		return ret;
C
Chris Mason 已提交
5085

5086 5087 5088
	for (i = start_i; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
		wait_on_page_locked(page);
C
Chris Mason 已提交
5089
		if (!PageUptodate(page))
5090 5091
			ret = -EIO;
	}
C
Chris Mason 已提交
5092

5093
	return ret;
5094 5095 5096

unlock_exit:
	i = start_i;
C
Chris Mason 已提交
5097
	while (locked_pages > 0) {
5098 5099 5100 5101 5102 5103
		page = extent_buffer_page(eb, i);
		i++;
		unlock_page(page);
		locked_pages--;
	}
	return ret;
5104 5105 5106 5107 5108 5109 5110 5111 5112 5113 5114 5115 5116 5117 5118 5119 5120
}

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);

5121
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5122

C
Chris Mason 已提交
5123
	while (len > 0) {
5124 5125 5126
		page = extent_buffer_page(eb, i);

		cur = min(len, (PAGE_CACHE_SIZE - offset));
5127
		kaddr = page_address(page);
5128 5129 5130 5131 5132 5133 5134 5135 5136
		memcpy(dst, kaddr + offset, cur);

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

5137 5138 5139 5140 5141 5142 5143 5144 5145 5146 5147 5148 5149 5150 5151 5152 5153 5154 5155 5156 5157 5158 5159 5160 5161 5162 5163 5164 5165 5166 5167 5168 5169 5170 5171 5172 5173
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) {
		page = extent_buffer_page(eb, i);

		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;
}

5174
int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
5175
			       unsigned long min_len, char **map,
5176
			       unsigned long *map_start,
5177
			       unsigned long *map_len)
5178 5179 5180 5181 5182 5183 5184 5185 5186 5187 5188 5189 5190 5191 5192 5193 5194 5195 5196
{
	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
5197

5198
	if (start + min_len > eb->len) {
J
Julia Lawall 已提交
5199
		WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
5200 5201
		       "wanted %lu %lu\n",
		       eb->start, eb->len, start, min_len);
5202
		return -EINVAL;
5203 5204 5205
	}

	p = extent_buffer_page(eb, i);
5206
	kaddr = page_address(p);
5207 5208 5209 5210 5211 5212 5213 5214 5215 5216 5217 5218 5219 5220 5221 5222 5223 5224 5225 5226 5227
	*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);

5228
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5229

C
Chris Mason 已提交
5230
	while (len > 0) {
5231 5232 5233 5234
		page = extent_buffer_page(eb, i);

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

5235
		kaddr = page_address(page);
5236 5237 5238 5239 5240 5241 5242 5243 5244 5245 5246 5247 5248 5249 5250 5251 5252 5253 5254 5255 5256 5257 5258 5259 5260 5261
		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);

5262
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5263

C
Chris Mason 已提交
5264
	while (len > 0) {
5265 5266 5267 5268
		page = extent_buffer_page(eb, i);
		WARN_ON(!PageUptodate(page));

		cur = min(len, PAGE_CACHE_SIZE - offset);
5269
		kaddr = page_address(page);
5270 5271 5272 5273 5274 5275 5276 5277 5278 5279 5280 5281 5282 5283 5284 5285 5286 5287 5288 5289 5290 5291
		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);

5292
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5293

C
Chris Mason 已提交
5294
	while (len > 0) {
5295 5296 5297 5298
		page = extent_buffer_page(eb, i);
		WARN_ON(!PageUptodate(page));

		cur = min(len, PAGE_CACHE_SIZE - offset);
5299
		kaddr = page_address(page);
5300 5301 5302 5303 5304 5305 5306 5307 5308 5309 5310 5311 5312 5313 5314 5315 5316 5317 5318 5319 5320 5321 5322
		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) &
5323
		(PAGE_CACHE_SIZE - 1);
5324

C
Chris Mason 已提交
5325
	while (len > 0) {
5326 5327 5328 5329 5330
		page = extent_buffer_page(dst, i);
		WARN_ON(!PageUptodate(page));

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

5331
		kaddr = page_address(page);
5332 5333 5334 5335 5336 5337 5338 5339 5340
		read_extent_buffer(src, kaddr + offset, src_offset, cur);

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

5341 5342 5343 5344 5345 5346
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;
}

5347 5348 5349 5350
static void copy_pages(struct page *dst_page, struct page *src_page,
		       unsigned long dst_off, unsigned long src_off,
		       unsigned long len)
{
5351
	char *dst_kaddr = page_address(dst_page);
5352
	char *src_kaddr;
5353
	int must_memmove = 0;
5354

5355
	if (dst_page != src_page) {
5356
		src_kaddr = page_address(src_page);
5357
	} else {
5358
		src_kaddr = dst_kaddr;
5359 5360
		if (areas_overlap(src_off, dst_off, len))
			must_memmove = 1;
5361
	}
5362

5363 5364 5365 5366
	if (must_memmove)
		memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
	else
		memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
5367 5368 5369 5370 5371 5372 5373 5374 5375 5376 5377 5378 5379
}

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) {
5380
		printk(KERN_ERR "BTRFS: memmove bogus src_offset %lu move "
C
Chris Mason 已提交
5381
		       "len %lu dst len %lu\n", src_offset, len, dst->len);
5382 5383 5384
		BUG_ON(1);
	}
	if (dst_offset + len > dst->len) {
5385
		printk(KERN_ERR "BTRFS: memmove bogus dst_offset %lu move "
C
Chris Mason 已提交
5386
		       "len %lu dst len %lu\n", dst_offset, len, dst->len);
5387 5388 5389
		BUG_ON(1);
	}

C
Chris Mason 已提交
5390
	while (len > 0) {
5391
		dst_off_in_page = (start_offset + dst_offset) &
5392
			(PAGE_CACHE_SIZE - 1);
5393
		src_off_in_page = (start_offset + src_offset) &
5394
			(PAGE_CACHE_SIZE - 1);
5395 5396 5397 5398 5399 5400 5401 5402 5403 5404 5405 5406 5407 5408 5409 5410 5411 5412 5413 5414 5415 5416 5417 5418 5419 5420 5421 5422 5423 5424 5425 5426

		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));

		copy_pages(extent_buffer_page(dst, dst_i),
			   extent_buffer_page(dst, src_i),
			   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) {
5427
		printk(KERN_ERR "BTRFS: memmove bogus src_offset %lu move "
C
Chris Mason 已提交
5428
		       "len %lu len %lu\n", src_offset, len, dst->len);
5429 5430 5431
		BUG_ON(1);
	}
	if (dst_offset + len > dst->len) {
5432
		printk(KERN_ERR "BTRFS: memmove bogus dst_offset %lu move "
C
Chris Mason 已提交
5433
		       "len %lu len %lu\n", dst_offset, len, dst->len);
5434 5435
		BUG_ON(1);
	}
5436
	if (dst_offset < src_offset) {
5437 5438 5439
		memcpy_extent_buffer(dst, dst_offset, src_offset, len);
		return;
	}
C
Chris Mason 已提交
5440
	while (len > 0) {
5441 5442 5443 5444
		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) &
5445
			(PAGE_CACHE_SIZE - 1);
5446
		src_off_in_page = (start_offset + src_end) &
5447
			(PAGE_CACHE_SIZE - 1);
5448 5449 5450

		cur = min_t(unsigned long, len, src_off_in_page + 1);
		cur = min(cur, dst_off_in_page + 1);
Z
Zach Brown 已提交
5451
		copy_pages(extent_buffer_page(dst, dst_i),
5452 5453 5454 5455 5456 5457 5458 5459 5460
			   extent_buffer_page(dst, src_i),
			   dst_off_in_page - cur + 1,
			   src_off_in_page - cur + 1, cur);

		dst_end -= cur;
		src_end -= cur;
		len -= cur;
	}
}
5461

5462
int try_release_extent_buffer(struct page *page)
5463
{
5464 5465
	struct extent_buffer *eb;

5466 5467 5468 5469 5470 5471 5472
	/*
	 * 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
5473
		return 1;
5474
	}
5475

5476 5477
	eb = (struct extent_buffer *)page->private;
	BUG_ON(!eb);
5478 5479

	/*
5480 5481 5482
	 * 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.
5483
	 */
5484
	spin_lock(&eb->refs_lock);
5485
	if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
5486 5487 5488
		spin_unlock(&eb->refs_lock);
		spin_unlock(&page->mapping->private_lock);
		return 0;
5489
	}
5490
	spin_unlock(&page->mapping->private_lock);
5491

5492
	/*
5493 5494
	 * 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.
5495
	 */
5496 5497 5498
	if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
		spin_unlock(&eb->refs_lock);
		return 0;
5499
	}
5500

5501
	return release_extent_buffer(eb);
5502
}