extent_io.c 135.2 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 "
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		       "refs %d\n",
		       eb->start, eb->len, atomic_read(&eb->refs));
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		list_del(&eb->leak_list);
		kmem_cache_free(extent_buffer_cache, eb);
	}
}
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#define btrfs_debug_check_extent_io_range(tree, start, end)		\
	__btrfs_debug_check_extent_io_range(__func__, (tree), (start), (end))
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static inline void __btrfs_debug_check_extent_io_range(const char *caller,
88
		struct extent_io_tree *tree, u64 start, u64 end)
89
{
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	struct inode *inode;
	u64 isize;
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93 94
	if (!tree->mapping)
		return;
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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);
445
		printk(KERN_ERR "BTRFS: found node %llu %llu on insert of "
446 447
		       "%llu %llu\n",
		       found->start, found->end, start, end);
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		return -EEXIST;
	}
	merge_state(tree, state);
	return 0;
}

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

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

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

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

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

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

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	if (bits & EXTENT_DELALLOC)
		bits |= EXTENT_NORESERVE;

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

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	if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
		clear = 1;
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again:
	if (!prealloc && (mask & __GFP_WAIT)) {
		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 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997
/*
 * When IO fails, either with EIO or csum verification fails, we
 * try other mirrors that might have a good copy of the data.  This
 * io_failure_record is used to record state as we go through all the
 * mirrors.  If another mirror has good data, the page is set up to date
 * and things continue.  If a good mirror can't be found, the original
 * bio end_io callback is called to indicate things have failed.
 */
struct io_failure_record {
	struct page *page;
	u64 start;
	u64 len;
	u64 logical;
	unsigned long bio_flags;
	int this_mirror;
	int failed_mirror;
	int in_validation;
};

static int free_io_failure(struct inode *inode, struct io_failure_record *rec,
				int did_repair)
{
	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
1998 1999 2000 2001 2002
	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;
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

	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.
2013
 * to avoid any synchronization issues, wait for the data after writing, which
2014 2015 2016 2017
 * 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.
 */
2018
int repair_io_failure(struct btrfs_fs_info *fs_info, u64 start,
2019 2020 2021 2022 2023 2024 2025 2026
			u64 length, u64 logical, struct page *page,
			int mirror_num)
{
	struct bio *bio;
	struct btrfs_device *dev;
	u64 map_length = 0;
	u64 sector;
	struct btrfs_bio *bbio = NULL;
D
David Woodhouse 已提交
2027
	struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
2028 2029
	int ret;

2030
	ASSERT(!(fs_info->sb->s_flags & MS_RDONLY));
2031 2032
	BUG_ON(!mirror_num);

D
David Woodhouse 已提交
2033 2034 2035 2036
	/* we can't repair anything in raid56 yet */
	if (btrfs_is_parity_mirror(map_tree, logical, length, mirror_num))
		return 0;

2037
	bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2038 2039
	if (!bio)
		return -EIO;
2040
	bio->bi_iter.bi_size = 0;
2041 2042
	map_length = length;

2043
	ret = btrfs_map_block(fs_info, WRITE, logical,
2044 2045 2046 2047 2048 2049 2050
			      &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;
2051
	bio->bi_iter.bi_sector = sector;
2052 2053 2054 2055 2056 2057 2058
	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;
M
Miao Xie 已提交
2059
	bio_add_page(bio, page, length, start - page_offset(page));
2060

2061
	if (btrfsic_submit_bio_wait(WRITE_SYNC, bio)) {
2062 2063
		/* try to remap that extent elsewhere? */
		bio_put(bio);
2064
		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
2065 2066 2067
		return -EIO;
	}

2068 2069 2070 2071
	printk_ratelimited_in_rcu(KERN_INFO
			"BTRFS: read error corrected: ino %lu off %llu "
		    "(dev %s sector %llu)\n", page->mapping->host->i_ino,
		    start, rcu_str_deref(dev->name), sector);
2072 2073 2074 2075 2076

	bio_put(bio);
	return 0;
}

2077 2078 2079 2080 2081
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);
2082
	int ret = 0;
2083

2084 2085 2086
	if (root->fs_info->sb->s_flags & MS_RDONLY)
		return -EROFS;

2087 2088
	for (i = 0; i < num_pages; i++) {
		struct page *p = extent_buffer_page(eb, i);
2089
		ret = repair_io_failure(root->fs_info, start, PAGE_CACHE_SIZE,
2090 2091 2092 2093 2094 2095 2096 2097 2098
					start, p, mirror_num);
		if (ret)
			break;
		start += PAGE_CACHE_SIZE;
	}

	return ret;
}

2099 2100 2101 2102 2103 2104 2105 2106 2107
/*
 * 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
 */
static int clean_io_failure(u64 start, struct page *page)
{
	u64 private;
	u64 private_failure;
	struct io_failure_record *failrec;
2108 2109
	struct inode *inode = page->mapping->host;
	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135
	struct extent_state *state;
	int num_copies;
	int did_repair = 0;
	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);
		did_repair = 1;
		goto out;
	}
2136 2137
	if (fs_info->sb->s_flags & MS_RDONLY)
		goto out;
2138 2139 2140 2141 2142 2143 2144

	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);

2145 2146
	if (state && state->start <= failrec->start &&
	    state->end >= failrec->start + failrec->len - 1) {
2147 2148
		num_copies = btrfs_num_copies(fs_info, failrec->logical,
					      failrec->len);
2149
		if (num_copies > 1)  {
2150
			ret = repair_io_failure(fs_info, start, failrec->len,
2151 2152 2153 2154
						failrec->logical, page,
						failrec->failed_mirror);
			did_repair = !ret;
		}
D
David Woodhouse 已提交
2155
		ret = 0;
2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172
	}

out:
	if (!ret)
		ret = free_io_failure(inode, failrec, did_repair);

	return ret;
}

/*
 * 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
 */

2173 2174 2175
static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
			      struct page *page, u64 start, u64 end,
			      int failed_mirror)
2176 2177 2178 2179 2180 2181 2182 2183 2184
{
	struct io_failure_record *failrec = NULL;
	u64 private;
	struct extent_map *em;
	struct inode *inode = page->mapping->host;
	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;
	struct bio *bio;
2185 2186
	struct btrfs_io_bio *btrfs_failed_bio;
	struct btrfs_io_bio *btrfs_bio;
2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212
	int num_copies;
	int ret;
	int read_mode;
	u64 logical;

	BUG_ON(failed_bio->bi_rw & REQ_WRITE);

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

2213
		if (em->start > start || em->start + em->len <= start) {
2214 2215 2216 2217 2218
			free_extent_map(em);
			em = NULL;
		}
		read_unlock(&em_tree->lock);

2219
		if (!em) {
2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261
			kfree(failrec);
			return -EIO;
		}
		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);
		}
		pr_debug("bio_readpage_error: (new) logical=%llu, start=%llu, "
			 "len=%llu\n", logical, start, failrec->len);
		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;
		pr_debug("bio_readpage_error: (found) logical=%llu, "
			 "start=%llu, len=%llu, validation=%d\n",
			 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.
		 */
	}
2262 2263
	num_copies = btrfs_num_copies(BTRFS_I(inode)->root->fs_info,
				      failrec->logical, failrec->len);
2264 2265 2266 2267 2268 2269
	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.
		 */
2270 2271
		pr_debug("bio_readpage_error: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d\n",
			 num_copies, failrec->this_mirror, failed_mirror);
2272 2273 2274 2275 2276 2277 2278 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
		free_io_failure(inode, failrec, 0);
		return -EIO;
	}

	/*
	 * 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;
		read_mode = READ_SYNC | REQ_FAILFAST_DEV;
	} 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++;
		read_mode = READ_SYNC;
	}

2312 2313
	if (failrec->this_mirror > num_copies) {
		pr_debug("bio_readpage_error: (fail) num_copies=%d, next_mirror %d, failed_mirror %d\n",
2314 2315 2316 2317 2318
			 num_copies, failrec->this_mirror, failed_mirror);
		free_io_failure(inode, failrec, 0);
		return -EIO;
	}

2319
	bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2320 2321 2322 2323
	if (!bio) {
		free_io_failure(inode, failrec, 0);
		return -EIO;
	}
2324
	bio->bi_end_io = failed_bio->bi_end_io;
2325
	bio->bi_iter.bi_sector = failrec->logical >> 9;
2326
	bio->bi_bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
2327
	bio->bi_iter.bi_size = 0;
2328

2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341
	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;
		phy_offset >>= inode->i_sb->s_blocksize_bits;
		phy_offset *= csum_size;
		memcpy(btrfs_bio->csum, btrfs_failed_bio->csum + phy_offset,
		       csum_size);
	}

2342 2343 2344 2345 2346 2347
	bio_add_page(bio, page, failrec->len, start - page_offset(page));

	pr_debug("bio_readpage_error: submitting new read[%#x] to "
		 "this_mirror=%d, num_copies=%d, in_validation=%d\n", read_mode,
		 failrec->this_mirror, num_copies, failrec->in_validation);

2348 2349 2350 2351
	ret = tree->ops->submit_bio_hook(inode, read_mode, bio,
					 failrec->this_mirror,
					 failrec->bio_flags, 0);
	return ret;
2352 2353
}

2354 2355
/* lots and lots of room for performance fixes in the end_bio funcs */

2356 2357 2358 2359
int end_extent_writepage(struct page *page, int err, u64 start, u64 end)
{
	int uptodate = (err == 0);
	struct extent_io_tree *tree;
2360
	int ret = 0;
2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373

	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);
2374 2375
		ret = ret < 0 ? ret : -EIO;
		mapping_set_error(page->mapping, ret);
2376 2377 2378 2379
	}
	return 0;
}

2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390
/*
 * 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)
{
2391
	struct bio_vec *bvec;
2392 2393
	u64 start;
	u64 end;
2394
	int i;
2395

2396
	bio_for_each_segment_all(bvec, bio, i) {
2397
		struct page *page = bvec->bv_page;
2398

2399 2400 2401 2402 2403
		/* 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.  */
2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414
		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);
		}
2415

2416 2417
		start = page_offset(page);
		end = start + bvec->bv_offset + bvec->bv_len - 1;
2418

2419 2420
		if (end_extent_writepage(page, err, start, end))
			continue;
2421

2422
		end_page_writeback(page);
2423
	}
2424

2425 2426 2427
	bio_put(bio);
}

2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439
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);
}

2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452
/*
 * 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)
{
2453
	struct bio_vec *bvec;
2454
	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
2455
	struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
2456
	struct extent_io_tree *tree;
2457
	u64 offset = 0;
2458 2459
	u64 start;
	u64 end;
2460
	u64 len;
2461 2462
	u64 extent_start = 0;
	u64 extent_len = 0;
2463
	int mirror;
2464
	int ret;
2465
	int i;
2466

2467 2468 2469
	if (err)
		uptodate = 0;

2470
	bio_for_each_segment_all(bvec, bio, i) {
2471
		struct page *page = bvec->bv_page;
2472
		struct inode *inode = page->mapping->host;
2473

2474
		pr_debug("end_bio_extent_readpage: bi_sector=%llu, err=%d, "
2475
			 "mirror=%lu\n", (u64)bio->bi_iter.bi_sector, err,
2476
			 io_bio->mirror_num);
2477
		tree = &BTRFS_I(inode)->io_tree;
2478

2479 2480 2481 2482 2483
		/* 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.  */
2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494
		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);
		}
2495

2496 2497
		start = page_offset(page);
		end = start + bvec->bv_offset + bvec->bv_len - 1;
2498
		len = bvec->bv_len;
2499

2500
		mirror = io_bio->mirror_num;
2501 2502
		if (likely(uptodate && tree->ops &&
			   tree->ops->readpage_end_io_hook)) {
2503 2504 2505
			ret = tree->ops->readpage_end_io_hook(io_bio, offset,
							      page, start, end,
							      mirror);
2506
			if (ret)
2507
				uptodate = 0;
2508
			else
2509
				clean_io_failure(start, page);
2510
		}
2511

2512 2513 2514 2515
		if (likely(uptodate))
			goto readpage_ok;

		if (tree->ops && tree->ops->readpage_io_failed_hook) {
2516
			ret = tree->ops->readpage_io_failed_hook(page, mirror);
2517 2518 2519
			if (!ret && !err &&
			    test_bit(BIO_UPTODATE, &bio->bi_flags))
				uptodate = 1;
2520
		} else {
2521 2522 2523 2524 2525 2526 2527 2528 2529 2530
			/*
			 * 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.
			 */
2531 2532
			ret = bio_readpage_error(bio, offset, page, start, end,
						 mirror);
2533
			if (ret == 0) {
2534 2535
				uptodate =
					test_bit(BIO_UPTODATE, &bio->bi_flags);
2536 2537
				if (err)
					uptodate = 0;
2538
				offset += len;
2539 2540 2541
				continue;
			}
		}
2542
readpage_ok:
2543
		if (likely(uptodate)) {
2544 2545 2546 2547 2548 2549 2550 2551
			loff_t i_size = i_size_read(inode);
			pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
			unsigned offset;

			/* Zero out the end if this page straddles i_size */
			offset = i_size & (PAGE_CACHE_SIZE-1);
			if (page->index == end_index && offset)
				zero_user_segment(page, offset, PAGE_CACHE_SIZE);
2552
			SetPageUptodate(page);
2553
		} else {
2554 2555
			ClearPageUptodate(page);
			SetPageError(page);
2556
		}
2557
		unlock_page(page);
2558
		offset += len;
2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580

		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;
		}
2581
	}
2582

2583 2584 2585
	if (extent_len)
		endio_readpage_release_extent(tree, extent_start, extent_len,
					      uptodate);
2586 2587
	if (io_bio->end_io)
		io_bio->end_io(io_bio, err);
2588 2589 2590
	bio_put(bio);
}

2591 2592 2593 2594
/*
 * 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
 */
2595 2596 2597
struct bio *
btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
		gfp_t gfp_flags)
2598
{
2599
	struct btrfs_io_bio *btrfs_bio;
2600 2601
	struct bio *bio;

2602
	bio = bio_alloc_bioset(gfp_flags, nr_vecs, btrfs_bioset);
2603 2604

	if (bio == NULL && (current->flags & PF_MEMALLOC)) {
2605 2606 2607 2608
		while (!bio && (nr_vecs /= 2)) {
			bio = bio_alloc_bioset(gfp_flags,
					       nr_vecs, btrfs_bioset);
		}
2609 2610 2611 2612
	}

	if (bio) {
		bio->bi_bdev = bdev;
2613
		bio->bi_iter.bi_sector = first_sector;
2614 2615 2616 2617
		btrfs_bio = btrfs_io_bio(bio);
		btrfs_bio->csum = NULL;
		btrfs_bio->csum_allocated = NULL;
		btrfs_bio->end_io = NULL;
2618 2619 2620 2621
	}
	return bio;
}

2622 2623 2624 2625 2626 2627 2628 2629 2630
struct bio *btrfs_bio_clone(struct bio *bio, gfp_t gfp_mask)
{
	return bio_clone_bioset(bio, gfp_mask, btrfs_bioset);
}


/* this also allocates from the btrfs_bioset */
struct bio *btrfs_io_bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
{
2631 2632 2633 2634 2635 2636 2637 2638 2639 2640 2641
	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;
2642 2643 2644
}


2645 2646
static int __must_check submit_one_bio(int rw, struct bio *bio,
				       int mirror_num, unsigned long bio_flags)
2647 2648
{
	int ret = 0;
2649 2650 2651 2652 2653
	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
2654
	start = page_offset(page) + bvec->bv_offset;
2655

2656
	bio->bi_private = NULL;
2657 2658 2659

	bio_get(bio);

2660
	if (tree->ops && tree->ops->submit_bio_hook)
2661
		ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
2662
					   mirror_num, bio_flags, start);
2663
	else
2664
		btrfsic_submit_bio(rw, bio);
2665

2666 2667 2668 2669 2670 2671
	if (bio_flagged(bio, BIO_EOPNOTSUPP))
		ret = -EOPNOTSUPP;
	bio_put(bio);
	return ret;
}

2672
static int merge_bio(int rw, struct extent_io_tree *tree, struct page *page,
2673 2674 2675 2676 2677
		     unsigned long offset, size_t size, struct bio *bio,
		     unsigned long bio_flags)
{
	int ret = 0;
	if (tree->ops && tree->ops->merge_bio_hook)
2678
		ret = tree->ops->merge_bio_hook(rw, page, offset, size, bio,
2679 2680 2681 2682 2683 2684
						bio_flags);
	BUG_ON(ret < 0);
	return ret;

}

2685 2686 2687 2688 2689 2690
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,
2691
			      bio_end_io_t end_io_func,
C
Chris Mason 已提交
2692 2693 2694
			      int mirror_num,
			      unsigned long prev_bio_flags,
			      unsigned long bio_flags)
2695 2696 2697 2698
{
	int ret = 0;
	struct bio *bio;
	int nr;
C
Chris Mason 已提交
2699 2700 2701
	int contig = 0;
	int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
	int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
2702
	size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
2703 2704 2705

	if (bio_ret && *bio_ret) {
		bio = *bio_ret;
C
Chris Mason 已提交
2706
		if (old_compressed)
2707
			contig = bio->bi_iter.bi_sector == sector;
C
Chris Mason 已提交
2708
		else
K
Kent Overstreet 已提交
2709
			contig = bio_end_sector(bio) == sector;
C
Chris Mason 已提交
2710 2711

		if (prev_bio_flags != bio_flags || !contig ||
2712
		    merge_bio(rw, tree, page, offset, page_size, bio, bio_flags) ||
C
Chris Mason 已提交
2713 2714 2715
		    bio_add_page(bio, page, page_size, offset) < page_size) {
			ret = submit_one_bio(rw, bio, mirror_num,
					     prev_bio_flags);
2716 2717
			if (ret < 0)
				return ret;
2718 2719 2720 2721 2722
			bio = NULL;
		} else {
			return 0;
		}
	}
C
Chris Mason 已提交
2723 2724 2725 2726 2727
	if (this_compressed)
		nr = BIO_MAX_PAGES;
	else
		nr = bio_get_nr_vecs(bdev);

2728
	bio = btrfs_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
2729 2730
	if (!bio)
		return -ENOMEM;
2731

C
Chris Mason 已提交
2732
	bio_add_page(bio, page, page_size, offset);
2733 2734
	bio->bi_end_io = end_io_func;
	bio->bi_private = tree;
2735

C
Chris Mason 已提交
2736
	if (bio_ret)
2737
		*bio_ret = bio;
C
Chris Mason 已提交
2738
	else
C
Chris Mason 已提交
2739
		ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
2740 2741 2742 2743

	return ret;
}

2744 2745
static void attach_extent_buffer_page(struct extent_buffer *eb,
				      struct page *page)
2746 2747 2748 2749
{
	if (!PagePrivate(page)) {
		SetPagePrivate(page);
		page_cache_get(page);
J
Josef Bacik 已提交
2750 2751 2752
		set_page_private(page, (unsigned long)eb);
	} else {
		WARN_ON(page->private != (unsigned long)eb);
2753 2754 2755
	}
}

J
Josef Bacik 已提交
2756
void set_page_extent_mapped(struct page *page)
2757
{
J
Josef Bacik 已提交
2758 2759 2760 2761 2762
	if (!PagePrivate(page)) {
		SetPagePrivate(page);
		page_cache_get(page);
		set_page_private(page, EXTENT_PAGE_PRIVATE);
	}
2763 2764
}

2765 2766 2767 2768 2769 2770 2771 2772 2773
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;
2774
		if (extent_map_in_tree(em) && start >= em->start &&
2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791
		    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;
}
2792 2793 2794 2795
/*
 * 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)
2796
 * XXX JDM: This needs looking at to ensure proper page locking
2797
 */
2798 2799 2800
static int __do_readpage(struct extent_io_tree *tree,
			 struct page *page,
			 get_extent_t *get_extent,
2801
			 struct extent_map **em_cached,
2802 2803
			 struct bio **bio, int mirror_num,
			 unsigned long *bio_flags, int rw)
2804 2805
{
	struct inode *inode = page->mapping->host;
M
Miao Xie 已提交
2806
	u64 start = page_offset(page);
2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818
	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;
2819
	int parent_locked = *bio_flags & EXTENT_BIO_PARENT_LOCKED;
2820
	size_t pg_offset = 0;
2821
	size_t iosize;
C
Chris Mason 已提交
2822
	size_t disk_io_size;
2823
	size_t blocksize = inode->i_sb->s_blocksize;
2824
	unsigned long this_bio_flag = *bio_flags & EXTENT_BIO_PARENT_LOCKED;
2825 2826 2827

	set_page_extent_mapped(page);

2828
	end = page_end;
D
Dan Magenheimer 已提交
2829 2830 2831
	if (!PageUptodate(page)) {
		if (cleancache_get_page(page) == 0) {
			BUG_ON(blocksize != PAGE_SIZE);
2832
			unlock_extent(tree, start, end);
D
Dan Magenheimer 已提交
2833 2834 2835 2836
			goto out;
		}
	}

C
Chris Mason 已提交
2837 2838 2839 2840 2841 2842
	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;
2843
			userpage = kmap_atomic(page);
C
Chris Mason 已提交
2844 2845
			memset(userpage + zero_offset, 0, iosize);
			flush_dcache_page(page);
2846
			kunmap_atomic(userpage);
C
Chris Mason 已提交
2847 2848
		}
	}
2849
	while (cur <= end) {
2850 2851
		unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;

2852 2853
		if (cur >= last_byte) {
			char *userpage;
2854 2855
			struct extent_state *cached = NULL;

2856
			iosize = PAGE_CACHE_SIZE - pg_offset;
2857
			userpage = kmap_atomic(page);
2858
			memset(userpage + pg_offset, 0, iosize);
2859
			flush_dcache_page(page);
2860
			kunmap_atomic(userpage);
2861
			set_extent_uptodate(tree, cur, cur + iosize - 1,
2862
					    &cached, GFP_NOFS);
2863 2864 2865 2866
			if (!parent_locked)
				unlock_extent_cached(tree, cur,
						     cur + iosize - 1,
						     &cached, GFP_NOFS);
2867 2868
			break;
		}
2869 2870
		em = __get_extent_map(inode, page, pg_offset, cur,
				      end - cur + 1, get_extent, em_cached);
2871
		if (IS_ERR_OR_NULL(em)) {
2872
			SetPageError(page);
2873 2874
			if (!parent_locked)
				unlock_extent(tree, cur, end);
2875 2876 2877 2878 2879 2880
			break;
		}
		extent_offset = cur - em->start;
		BUG_ON(extent_map_end(em) <= cur);
		BUG_ON(end < cur);

2881
		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2882
			this_bio_flag |= EXTENT_BIO_COMPRESSED;
2883 2884 2885
			extent_set_compress_type(&this_bio_flag,
						 em->compress_type);
		}
C
Chris Mason 已提交
2886

2887 2888
		iosize = min(extent_map_end(em) - cur, end - cur + 1);
		cur_end = min(extent_map_end(em) - 1, end);
2889
		iosize = ALIGN(iosize, blocksize);
C
Chris Mason 已提交
2890 2891 2892 2893 2894 2895 2896
		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;
		}
2897 2898
		bdev = em->bdev;
		block_start = em->block_start;
Y
Yan Zheng 已提交
2899 2900
		if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
			block_start = EXTENT_MAP_HOLE;
2901 2902 2903 2904 2905 2906
		free_extent_map(em);
		em = NULL;

		/* we've found a hole, just zero and go on */
		if (block_start == EXTENT_MAP_HOLE) {
			char *userpage;
2907 2908
			struct extent_state *cached = NULL;

2909
			userpage = kmap_atomic(page);
2910
			memset(userpage + pg_offset, 0, iosize);
2911
			flush_dcache_page(page);
2912
			kunmap_atomic(userpage);
2913 2914

			set_extent_uptodate(tree, cur, cur + iosize - 1,
2915 2916 2917
					    &cached, GFP_NOFS);
			unlock_extent_cached(tree, cur, cur + iosize - 1,
			                     &cached, GFP_NOFS);
2918
			cur = cur + iosize;
2919
			pg_offset += iosize;
2920 2921 2922
			continue;
		}
		/* the get_extent function already copied into the page */
2923 2924
		if (test_range_bit(tree, cur, cur_end,
				   EXTENT_UPTODATE, 1, NULL)) {
2925
			check_page_uptodate(tree, page);
2926 2927
			if (!parent_locked)
				unlock_extent(tree, cur, cur + iosize - 1);
2928
			cur = cur + iosize;
2929
			pg_offset += iosize;
2930 2931
			continue;
		}
2932 2933 2934 2935 2936
		/* we have an inline extent but it didn't get marked up
		 * to date.  Error out
		 */
		if (block_start == EXTENT_MAP_INLINE) {
			SetPageError(page);
2937 2938
			if (!parent_locked)
				unlock_extent(tree, cur, cur + iosize - 1);
2939
			cur = cur + iosize;
2940
			pg_offset += iosize;
2941 2942
			continue;
		}
2943

2944
		pnr -= page->index;
2945
		ret = submit_extent_page(rw, tree, page,
2946
					 sector, disk_io_size, pg_offset,
2947
					 bdev, bio, pnr,
C
Chris Mason 已提交
2948 2949 2950
					 end_bio_extent_readpage, mirror_num,
					 *bio_flags,
					 this_bio_flag);
2951 2952 2953 2954
		if (!ret) {
			nr++;
			*bio_flags = this_bio_flag;
		} else {
2955
			SetPageError(page);
2956 2957
			if (!parent_locked)
				unlock_extent(tree, cur, cur + iosize - 1);
2958
		}
2959
		cur = cur + iosize;
2960
		pg_offset += iosize;
2961
	}
D
Dan Magenheimer 已提交
2962
out:
2963 2964 2965 2966 2967 2968 2969 2970
	if (!nr) {
		if (!PageError(page))
			SetPageUptodate(page);
		unlock_page(page);
	}
	return 0;
}

2971 2972 2973 2974
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,
2975
					     struct extent_map **em_cached,
2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995
					     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++) {
2996 2997
		__do_readpage(tree, pages[index], get_extent, em_cached, bio,
			      mirror_num, bio_flags, rw);
2998 2999 3000 3001 3002 3003 3004
		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,
3005
			       struct extent_map **em_cached,
3006 3007 3008
			       struct bio **bio, int mirror_num,
			       unsigned long *bio_flags, int rw)
{
3009
	u64 start = 0;
3010 3011 3012
	u64 end = 0;
	u64 page_start;
	int index;
3013
	int first_index = 0;
3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025

	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,
3026 3027 3028
						  end, get_extent, em_cached,
						  bio, mirror_num, bio_flags,
						  rw);
3029 3030 3031 3032 3033 3034 3035 3036 3037
			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,
3038
					  end, get_extent, em_cached, bio,
3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063
					  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);
	}

3064 3065
	ret = __do_readpage(tree, page, get_extent, NULL, bio, mirror_num,
			    bio_flags, rw);
3066 3067 3068
	return ret;
}

3069
int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
3070
			    get_extent_t *get_extent, int mirror_num)
3071 3072
{
	struct bio *bio = NULL;
C
Chris Mason 已提交
3073
	unsigned long bio_flags = 0;
3074 3075
	int ret;

3076
	ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
3077
				      &bio_flags, READ);
3078
	if (bio)
3079
		ret = submit_one_bio(READ, bio, mirror_num, bio_flags);
3080 3081 3082
	return ret;
}

3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096
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;
}

3097 3098 3099 3100 3101 3102 3103 3104 3105 3106
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;
}

3107
/*
3108 3109 3110 3111 3112 3113 3114 3115
 * 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)
3116
 */
3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212
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)
3213 3214
{
	struct extent_io_tree *tree = epd->tree;
M
Miao Xie 已提交
3215
	u64 start = page_offset(page);
3216 3217 3218 3219 3220 3221 3222
	u64 page_end = start + PAGE_CACHE_SIZE - 1;
	u64 end;
	u64 cur = start;
	u64 extent_offset;
	u64 block_start;
	u64 iosize;
	sector_t sector;
3223
	struct extent_state *cached_state = NULL;
3224 3225
	struct extent_map *em;
	struct block_device *bdev;
3226
	size_t pg_offset = 0;
3227
	size_t blocksize;
3228 3229 3230
	int ret = 0;
	int nr = 0;
	bool compressed;
C
Chris Mason 已提交
3231

3232
	if (tree->ops && tree->ops->writepage_start_hook) {
C
Chris Mason 已提交
3233 3234
		ret = tree->ops->writepage_start_hook(page, start,
						      page_end);
3235 3236 3237 3238 3239 3240
		if (ret) {
			/* Fixup worker will requeue */
			if (ret == -EBUSY)
				wbc->pages_skipped++;
			else
				redirty_page_for_writepage(wbc, page);
3241

3242
			update_nr_written(page, wbc, nr_written);
3243
			unlock_page(page);
3244
			ret = 1;
3245
			goto done_unlocked;
3246 3247 3248
		}
	}

3249 3250 3251 3252 3253
	/*
	 * 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);
3254

3255
	end = page_end;
3256
	if (i_size <= start) {
3257 3258 3259
		if (tree->ops && tree->ops->writepage_end_io_hook)
			tree->ops->writepage_end_io_hook(page, start,
							 page_end, NULL, 1);
3260 3261 3262 3263 3264 3265
		goto done;
	}

	blocksize = inode->i_sb->s_blocksize;

	while (cur <= end) {
3266 3267
		u64 em_end;
		if (cur >= i_size) {
3268 3269 3270
			if (tree->ops && tree->ops->writepage_end_io_hook)
				tree->ops->writepage_end_io_hook(page, cur,
							 page_end, NULL, 1);
3271 3272
			break;
		}
3273
		em = epd->get_extent(inode, page, pg_offset, cur,
3274
				     end - cur + 1, 1);
3275
		if (IS_ERR_OR_NULL(em)) {
3276
			SetPageError(page);
3277
			ret = PTR_ERR_OR_ZERO(em);
3278 3279 3280 3281
			break;
		}

		extent_offset = cur - em->start;
3282 3283
		em_end = extent_map_end(em);
		BUG_ON(em_end <= cur);
3284
		BUG_ON(end < cur);
3285
		iosize = min(em_end - cur, end - cur + 1);
3286
		iosize = ALIGN(iosize, blocksize);
3287 3288 3289
		sector = (em->block_start + extent_offset) >> 9;
		bdev = em->bdev;
		block_start = em->block_start;
C
Chris Mason 已提交
3290
		compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
3291 3292 3293
		free_extent_map(em);
		em = NULL;

C
Chris Mason 已提交
3294 3295 3296 3297 3298
		/*
		 * compressed and inline extents are written through other
		 * paths in the FS
		 */
		if (compressed || block_start == EXTENT_MAP_HOLE ||
3299
		    block_start == EXTENT_MAP_INLINE) {
C
Chris Mason 已提交
3300 3301 3302 3303 3304 3305
			/*
			 * end_io notification does not happen here for
			 * compressed extents
			 */
			if (!compressed && tree->ops &&
			    tree->ops->writepage_end_io_hook)
3306 3307 3308
				tree->ops->writepage_end_io_hook(page, cur,
							 cur + iosize - 1,
							 NULL, 1);
C
Chris Mason 已提交
3309 3310 3311 3312 3313 3314 3315 3316 3317
			else if (compressed) {
				/* we don't want to end_page_writeback on
				 * a compressed extent.  this happens
				 * elsewhere
				 */
				nr++;
			}

			cur += iosize;
3318
			pg_offset += iosize;
3319 3320
			continue;
		}
C
Chris Mason 已提交
3321

3322 3323 3324 3325 3326 3327
		if (tree->ops && tree->ops->writepage_io_hook) {
			ret = tree->ops->writepage_io_hook(page, cur,
						cur + iosize - 1);
		} else {
			ret = 0;
		}
3328
		if (ret) {
3329
			SetPageError(page);
3330
		} else {
3331
			unsigned long max_nr = (i_size >> PAGE_CACHE_SHIFT) + 1;
3332

3333 3334
			set_range_writeback(tree, cur, cur + iosize - 1);
			if (!PageWriteback(page)) {
3335 3336
				btrfs_err(BTRFS_I(inode)->root->fs_info,
					   "page %lu not writeback, cur %llu end %llu",
3337
				       page->index, cur, end);
3338 3339
			}

3340 3341 3342
			ret = submit_extent_page(write_flags, tree, page,
						 sector, iosize, pg_offset,
						 bdev, &epd->bio, max_nr,
C
Chris Mason 已提交
3343 3344
						 end_bio_extent_writepage,
						 0, 0, 0);
3345 3346 3347 3348
			if (ret)
				SetPageError(page);
		}
		cur = cur + iosize;
3349
		pg_offset += iosize;
3350 3351
		nr++;
	}
3352 3353 3354 3355 3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426
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;

3427 3428 3429 3430 3431 3432
done:
	if (nr == 0) {
		/* make sure the mapping tag for page dirty gets cleared */
		set_page_writeback(page);
		end_page_writeback(page);
	}
3433 3434 3435 3436
	if (PageError(page)) {
		ret = ret < 0 ? ret : -EIO;
		end_extent_writepage(page, ret, start, page_end);
	}
3437
	unlock_page(page);
3438
	return ret;
3439

3440
done_unlocked:
3441 3442 3443
	return 0;
}

3444
void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
3445
{
3446 3447
	wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
		       TASK_UNINTERRUPTIBLE);
3448 3449
}

3450 3451 3452 3453
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)
3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472
{
	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
3473 3474 3475 3476 3477
		while (1) {
			wait_on_extent_buffer_writeback(eb);
			btrfs_tree_lock(eb);
			if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
				break;
3478 3479 3480 3481
			btrfs_tree_unlock(eb);
		}
	}

3482 3483 3484 3485 3486 3487
	/*
	 * 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);
3488 3489
	if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
		set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3490
		spin_unlock(&eb->refs_lock);
3491
		btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3492 3493 3494
		__percpu_counter_add(&fs_info->dirty_metadata_bytes,
				     -eb->len,
				     fs_info->dirty_metadata_batch);
3495
		ret = 1;
3496 3497
	} else {
		spin_unlock(&eb->refs_lock);
3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523
	}

	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);
3524
	smp_mb__after_atomic();
3525 3526 3527 3528 3529
	wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
}

static void end_bio_extent_buffer_writepage(struct bio *bio, int err)
{
3530
	struct bio_vec *bvec;
3531
	struct extent_buffer *eb;
3532
	int i, done;
3533

3534
	bio_for_each_segment_all(bvec, bio, i) {
3535 3536 3537 3538 3539 3540
		struct page *page = bvec->bv_page;

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

3541
		if (err || test_bit(EXTENT_BUFFER_IOERR, &eb->bflags)) {
3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552
			set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
			ClearPageUptodate(page);
			SetPageError(page);
		}

		end_page_writeback(page);

		if (!done)
			continue;

		end_extent_buffer_writeback(eb);
3553
	}
3554 3555 3556 3557

	bio_put(bio);
}

3558
static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
3559 3560 3561 3562 3563
			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;
3564
	struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
3565 3566
	u64 offset = eb->start;
	unsigned long i, num_pages;
3567
	unsigned long bio_flags = 0;
3568
	int rw = (epd->sync_io ? WRITE_SYNC : WRITE) | REQ_META;
3569
	int ret = 0;
3570 3571 3572 3573

	clear_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
	num_pages = num_extent_pages(eb->start, eb->len);
	atomic_set(&eb->io_pages, num_pages);
3574 3575 3576
	if (btrfs_header_owner(eb) == BTRFS_TREE_LOG_OBJECTID)
		bio_flags = EXTENT_BIO_TREE_LOG;

3577 3578 3579 3580 3581
	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);
3582
		ret = submit_extent_page(rw, tree, p, offset >> 9,
3583 3584
					 PAGE_CACHE_SIZE, 0, bdev, &epd->bio,
					 -1, end_bio_extent_buffer_writepage,
3585 3586
					 0, epd->bio_flags, bio_flags);
		epd->bio_flags = bio_flags;
3587 3588 3589 3590 3591 3592 3593 3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620
		if (ret) {
			set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
			SetPageError(p);
			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);
			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,
3621
		.bio_flags = 0,
3622 3623 3624 3625 3626 3627 3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651 3652 3653 3654 3655 3656 3657 3658 3659 3660 3661 3662 3663 3664 3665
	};
	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;
			}

3666 3667 3668 3669 3670 3671
			spin_lock(&mapping->private_lock);
			if (!PagePrivate(page)) {
				spin_unlock(&mapping->private_lock);
				continue;
			}

3672
			eb = (struct extent_buffer *)page->private;
3673 3674 3675 3676 3677 3678

			/*
			 * 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.
			 */
3679
			if (WARN_ON(!eb)) {
3680
				spin_unlock(&mapping->private_lock);
3681 3682 3683
				continue;
			}

3684 3685
			if (eb == prev_eb) {
				spin_unlock(&mapping->private_lock);
3686
				continue;
3687
			}
3688

3689 3690 3691
			ret = atomic_inc_not_zero(&eb->refs);
			spin_unlock(&mapping->private_lock);
			if (!ret)
3692 3693 3694 3695 3696 3697 3698 3699 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
				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;
}

3732
/**
C
Chris Mason 已提交
3733
 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
3734 3735 3736 3737 3738 3739 3740 3741 3742 3743 3744 3745 3746
 * @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.
 */
3747
static int extent_write_cache_pages(struct extent_io_tree *tree,
C
Chris Mason 已提交
3748 3749
			     struct address_space *mapping,
			     struct writeback_control *wbc,
C
Chris Mason 已提交
3750 3751
			     writepage_t writepage, void *data,
			     void (*flush_fn)(void *))
3752
{
3753
	struct inode *inode = mapping->host;
3754 3755
	int ret = 0;
	int done = 0;
3756
	int err = 0;
3757
	int nr_to_write_done = 0;
3758 3759 3760 3761 3762
	struct pagevec pvec;
	int nr_pages;
	pgoff_t index;
	pgoff_t end;		/* Inclusive */
	int scanned = 0;
3763
	int tag;
3764

3765 3766 3767 3768 3769 3770 3771 3772 3773 3774 3775 3776
	/*
	 * 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;

3777 3778 3779 3780 3781 3782 3783 3784 3785
	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;
	}
3786 3787 3788 3789
	if (wbc->sync_mode == WB_SYNC_ALL)
		tag = PAGECACHE_TAG_TOWRITE;
	else
		tag = PAGECACHE_TAG_DIRTY;
3790
retry:
3791 3792
	if (wbc->sync_mode == WB_SYNC_ALL)
		tag_pages_for_writeback(mapping, index, end);
3793
	while (!done && !nr_to_write_done && (index <= end) &&
3794 3795
	       (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
			min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
3796 3797 3798 3799 3800 3801 3802 3803 3804 3805 3806 3807 3808
		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
			 */
3809 3810 3811
			if (!trylock_page(page)) {
				flush_fn(data);
				lock_page(page);
3812
			}
3813 3814 3815 3816 3817 3818 3819 3820 3821 3822 3823 3824

			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
3825
			if (wbc->sync_mode != WB_SYNC_NONE) {
3826 3827
				if (PageWriteback(page))
					flush_fn(data);
3828
				wait_on_page_writeback(page);
C
Chris Mason 已提交
3829
			}
3830 3831 3832 3833 3834 3835 3836 3837 3838 3839 3840 3841 3842

			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;
			}
3843 3844
			if (!err && ret < 0)
				err = ret;
3845 3846 3847 3848 3849 3850 3851

			/*
			 * 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;
3852 3853 3854 3855
		}
		pagevec_release(&pvec);
		cond_resched();
	}
3856
	if (!scanned && !done && !err) {
3857 3858 3859 3860 3861 3862 3863 3864
		/*
		 * 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;
	}
3865
	btrfs_add_delayed_iput(inode);
3866
	return err;
3867 3868
}

3869
static void flush_epd_write_bio(struct extent_page_data *epd)
C
Chris Mason 已提交
3870 3871
{
	if (epd->bio) {
3872 3873 3874
		int rw = WRITE;
		int ret;

3875
		if (epd->sync_io)
3876 3877
			rw = WRITE_SYNC;

3878
		ret = submit_one_bio(rw, epd->bio, 0, epd->bio_flags);
3879
		BUG_ON(ret < 0); /* -ENOMEM */
C
Chris Mason 已提交
3880 3881 3882 3883
		epd->bio = NULL;
	}
}

3884 3885 3886 3887 3888 3889
static noinline void flush_write_bio(void *data)
{
	struct extent_page_data *epd = data;
	flush_epd_write_bio(epd);
}

3890 3891 3892 3893 3894 3895 3896 3897 3898
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,
3899
		.extent_locked = 0,
3900
		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
3901
		.bio_flags = 0,
3902 3903 3904 3905
	};

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

3906
	flush_epd_write_bio(&epd);
3907 3908 3909
	return ret;
}

3910 3911 3912 3913 3914 3915 3916 3917 3918 3919 3920 3921 3922 3923 3924
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,
3925
		.sync_io = mode == WB_SYNC_ALL,
3926
		.bio_flags = 0,
3927 3928 3929 3930 3931 3932 3933 3934
	};
	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
3935
	while (start <= end) {
3936 3937 3938 3939 3940 3941 3942 3943 3944 3945 3946 3947 3948 3949
		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;
	}

3950
	flush_epd_write_bio(&epd);
3951 3952
	return ret;
}
3953 3954 3955 3956 3957 3958 3959 3960 3961 3962 3963

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,
3964
		.extent_locked = 0,
3965
		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
3966
		.bio_flags = 0,
3967 3968
	};

C
Chris Mason 已提交
3969
	ret = extent_write_cache_pages(tree, mapping, wbc,
C
Chris Mason 已提交
3970 3971
				       __extent_writepage, &epd,
				       flush_write_bio);
3972
	flush_epd_write_bio(&epd);
3973 3974 3975 3976 3977 3978 3979 3980 3981 3982
	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
3983
	unsigned long bio_flags = 0;
L
Liu Bo 已提交
3984 3985
	struct page *pagepool[16];
	struct page *page;
3986
	struct extent_map *em_cached = NULL;
L
Liu Bo 已提交
3987
	int nr = 0;
3988 3989

	for (page_idx = 0; page_idx < nr_pages; page_idx++) {
L
Liu Bo 已提交
3990
		page = list_entry(pages->prev, struct page, lru);
3991 3992 3993

		prefetchw(&page->flags);
		list_del(&page->lru);
L
Liu Bo 已提交
3994
		if (add_to_page_cache_lru(page, mapping,
3995
					page->index, GFP_NOFS)) {
L
Liu Bo 已提交
3996 3997
			page_cache_release(page);
			continue;
3998
		}
L
Liu Bo 已提交
3999 4000 4001 4002

		pagepool[nr++] = page;
		if (nr < ARRAY_SIZE(pagepool))
			continue;
4003
		__extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
4004
				   &bio, 0, &bio_flags, READ);
L
Liu Bo 已提交
4005
		nr = 0;
4006
	}
4007
	if (nr)
4008
		__extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
4009
				   &bio, 0, &bio_flags, READ);
L
Liu Bo 已提交
4010

4011 4012 4013
	if (em_cached)
		free_extent_map(em_cached);

4014 4015
	BUG_ON(!list_empty(pages));
	if (bio)
4016
		return submit_one_bio(READ, bio, 0, bio_flags);
4017 4018 4019 4020 4021 4022 4023 4024 4025 4026 4027
	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)
{
4028
	struct extent_state *cached_state = NULL;
M
Miao Xie 已提交
4029
	u64 start = page_offset(page);
4030 4031 4032
	u64 end = start + PAGE_CACHE_SIZE - 1;
	size_t blocksize = page->mapping->host->i_sb->s_blocksize;

4033
	start += ALIGN(offset, blocksize);
4034 4035 4036
	if (start > end)
		return 0;

4037
	lock_extent_bits(tree, start, end, 0, &cached_state);
4038
	wait_on_page_writeback(page);
4039
	clear_extent_bit(tree, start, end,
4040 4041
			 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
			 EXTENT_DO_ACCOUNTING,
4042
			 1, 1, &cached_state, GFP_NOFS);
4043 4044 4045
	return 0;
}

4046 4047 4048 4049 4050
/*
 * 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.
 */
4051 4052 4053
static int try_release_extent_state(struct extent_map_tree *map,
				    struct extent_io_tree *tree,
				    struct page *page, gfp_t mask)
4054
{
M
Miao Xie 已提交
4055
	u64 start = page_offset(page);
4056 4057 4058
	u64 end = start + PAGE_CACHE_SIZE - 1;
	int ret = 1;

4059
	if (test_range_bit(tree, start, end,
4060
			   EXTENT_IOBITS, 0, NULL))
4061 4062 4063 4064
		ret = 0;
	else {
		if ((mask & GFP_NOFS) == GFP_NOFS)
			mask = GFP_NOFS;
4065 4066 4067 4068
		/*
		 * at this point we can safely clear everything except the
		 * locked bit and the nodatasum bit
		 */
4069
		ret = clear_extent_bit(tree, start, end,
4070 4071
				 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
				 0, 0, NULL, mask);
4072 4073 4074 4075 4076 4077 4078 4079

		/* if clear_extent_bit failed for enomem reasons,
		 * we can't allow the release to continue.
		 */
		if (ret < 0)
			ret = 0;
		else
			ret = 1;
4080 4081 4082 4083
	}
	return ret;
}

4084 4085 4086 4087 4088 4089
/*
 * 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,
4090 4091
			       struct extent_io_tree *tree, struct page *page,
			       gfp_t mask)
4092 4093
{
	struct extent_map *em;
M
Miao Xie 已提交
4094
	u64 start = page_offset(page);
4095
	u64 end = start + PAGE_CACHE_SIZE - 1;
4096

4097 4098
	if ((mask & __GFP_WAIT) &&
	    page->mapping->host->i_size > 16 * 1024 * 1024) {
4099
		u64 len;
4100
		while (start <= end) {
4101
			len = end - start + 1;
4102
			write_lock(&map->lock);
4103
			em = lookup_extent_mapping(map, start, len);
4104
			if (!em) {
4105
				write_unlock(&map->lock);
4106 4107
				break;
			}
4108 4109
			if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
			    em->start != start) {
4110
				write_unlock(&map->lock);
4111 4112 4113 4114 4115
				free_extent_map(em);
				break;
			}
			if (!test_range_bit(tree, em->start,
					    extent_map_end(em) - 1,
4116
					    EXTENT_LOCKED | EXTENT_WRITEBACK,
4117
					    0, NULL)) {
4118 4119 4120 4121 4122
				remove_extent_mapping(map, em);
				/* once for the rb tree */
				free_extent_map(em);
			}
			start = extent_map_end(em);
4123
			write_unlock(&map->lock);
4124 4125

			/* once for us */
4126 4127 4128
			free_extent_map(em);
		}
	}
4129
	return try_release_extent_state(map, tree, page, mask);
4130 4131
}

4132 4133 4134 4135 4136 4137 4138 4139 4140 4141 4142 4143 4144 4145 4146 4147
/*
 * 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;

4148
	while (1) {
4149 4150 4151
		len = last - offset;
		if (len == 0)
			break;
4152
		len = ALIGN(len, sectorsize);
4153
		em = get_extent(inode, NULL, 0, offset, len, 0);
4154
		if (IS_ERR_OR_NULL(em))
4155 4156 4157 4158 4159 4160 4161 4162 4163 4164 4165 4166 4167 4168 4169 4170 4171
			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;
}

4172 4173 4174 4175 4176 4177 4178 4179 4180 4181 4182 4183 4184
static noinline int count_ext_ref(u64 inum, u64 offset, u64 root_id, void *ctx)
{
	unsigned long cnt = *((unsigned long *)ctx);

	cnt++;
	*((unsigned long *)ctx) = cnt;

	/* Now we're sure that the extent is shared. */
	if (cnt > 1)
		return 1;
	return 0;
}

Y
Yehuda Sadeh 已提交
4185 4186 4187
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
4188
	int ret = 0;
Y
Yehuda Sadeh 已提交
4189 4190 4191
	u64 off = start;
	u64 max = start + len;
	u32 flags = 0;
J
Josef Bacik 已提交
4192 4193
	u32 found_type;
	u64 last;
4194
	u64 last_for_get_extent = 0;
Y
Yehuda Sadeh 已提交
4195
	u64 disko = 0;
4196
	u64 isize = i_size_read(inode);
J
Josef Bacik 已提交
4197
	struct btrfs_key found_key;
Y
Yehuda Sadeh 已提交
4198
	struct extent_map *em = NULL;
4199
	struct extent_state *cached_state = NULL;
J
Josef Bacik 已提交
4200
	struct btrfs_path *path;
Y
Yehuda Sadeh 已提交
4201
	int end = 0;
4202 4203 4204
	u64 em_start = 0;
	u64 em_len = 0;
	u64 em_end = 0;
Y
Yehuda Sadeh 已提交
4205 4206 4207 4208

	if (len == 0)
		return -EINVAL;

J
Josef Bacik 已提交
4209 4210 4211 4212 4213
	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
	path->leave_spinning = 1;

4214 4215
	start = round_down(start, BTRFS_I(inode)->root->sectorsize);
	len = round_up(max, BTRFS_I(inode)->root->sectorsize) - start;
4216

4217 4218 4219 4220
	/*
	 * lookup the last file extent.  We're not using i_size here
	 * because there might be preallocation past i_size
	 */
J
Josef Bacik 已提交
4221
	ret = btrfs_lookup_file_extent(NULL, BTRFS_I(inode)->root,
L
Li Zefan 已提交
4222
				       path, btrfs_ino(inode), -1, 0);
J
Josef Bacik 已提交
4223 4224 4225 4226 4227 4228 4229
	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]);
4230
	found_type = found_key.type;
J
Josef Bacik 已提交
4231

4232
	/* No extents, but there might be delalloc bits */
L
Li Zefan 已提交
4233
	if (found_key.objectid != btrfs_ino(inode) ||
J
Josef Bacik 已提交
4234
	    found_type != BTRFS_EXTENT_DATA_KEY) {
4235 4236 4237 4238 4239 4240 4241 4242 4243 4244 4245
		/* 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
4246
	}
4247
	btrfs_release_path(path);
J
Josef Bacik 已提交
4248

4249 4250 4251 4252 4253 4254 4255 4256 4257 4258
	/*
	 * 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
4259
	lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len - 1, 0,
4260
			 &cached_state);
4261

4262
	em = get_extent_skip_holes(inode, start, last_for_get_extent,
4263
				   get_extent);
Y
Yehuda Sadeh 已提交
4264 4265 4266 4267 4268 4269
	if (!em)
		goto out;
	if (IS_ERR(em)) {
		ret = PTR_ERR(em);
		goto out;
	}
J
Josef Bacik 已提交
4270

Y
Yehuda Sadeh 已提交
4271
	while (!end) {
4272
		u64 offset_in_extent = 0;
4273 4274 4275 4276 4277 4278 4279 4280 4281 4282 4283 4284

		/* 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
4285

4286 4287
		/*
		 * record the offset from the start of the extent
4288 4289 4290
		 * 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.
4291
		 */
4292 4293
		if (!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
			offset_in_extent = em_start - em->start;
4294
		em_end = extent_map_end(em);
4295
		em_len = em_end - em_start;
Y
Yehuda Sadeh 已提交
4296 4297 4298
		disko = 0;
		flags = 0;

4299 4300 4301 4302 4303 4304 4305
		/*
		 * bump off for our next call to get_extent
		 */
		off = extent_map_end(em);
		if (off >= max)
			end = 1;

4306
		if (em->block_start == EXTENT_MAP_LAST_BYTE) {
Y
Yehuda Sadeh 已提交
4307 4308
			end = 1;
			flags |= FIEMAP_EXTENT_LAST;
4309
		} else if (em->block_start == EXTENT_MAP_INLINE) {
Y
Yehuda Sadeh 已提交
4310 4311
			flags |= (FIEMAP_EXTENT_DATA_INLINE |
				  FIEMAP_EXTENT_NOT_ALIGNED);
4312
		} else if (em->block_start == EXTENT_MAP_DELALLOC) {
Y
Yehuda Sadeh 已提交
4313 4314
			flags |= (FIEMAP_EXTENT_DELALLOC |
				  FIEMAP_EXTENT_UNKNOWN);
4315
		} else {
4316 4317
			unsigned long ref_cnt = 0;

4318
			disko = em->block_start + offset_in_extent;
4319 4320 4321 4322 4323 4324 4325 4326 4327 4328 4329 4330 4331 4332 4333

			/*
			 * As btrfs supports shared space, this information
			 * can be exported to userspace tools via
			 * flag FIEMAP_EXTENT_SHARED.
			 */
			ret = iterate_inodes_from_logical(
					em->block_start,
					BTRFS_I(inode)->root->fs_info,
					path, count_ext_ref, &ref_cnt);
			if (ret < 0 && ret != -ENOENT)
				goto out_free;

			if (ref_cnt > 1)
				flags |= FIEMAP_EXTENT_SHARED;
Y
Yehuda Sadeh 已提交
4334 4335 4336 4337 4338 4339
		}
		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
			flags |= FIEMAP_EXTENT_ENCODED;

		free_extent_map(em);
		em = NULL;
4340 4341
		if ((em_start >= last) || em_len == (u64)-1 ||
		   (last == (u64)-1 && isize <= em_end)) {
Y
Yehuda Sadeh 已提交
4342 4343 4344 4345
			flags |= FIEMAP_EXTENT_LAST;
			end = 1;
		}

4346 4347 4348 4349 4350 4351 4352 4353
		/* 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
4354 4355 4356
			flags |= FIEMAP_EXTENT_LAST;
			end = 1;
		}
4357 4358 4359 4360
		ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
					      em_len, flags);
		if (ret)
			goto out_free;
Y
Yehuda Sadeh 已提交
4361 4362 4363 4364
	}
out_free:
	free_extent_map(em);
out:
4365
	btrfs_free_path(path);
L
Liu Bo 已提交
4366
	unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4367
			     &cached_state, GFP_NOFS);
Y
Yehuda Sadeh 已提交
4368 4369 4370
	return ret;
}

4371 4372
static void __free_extent_buffer(struct extent_buffer *eb)
{
4373
	btrfs_leak_debug_del(&eb->leak_list);
4374 4375 4376
	kmem_cache_free(extent_buffer_cache, eb);
}

4377
int extent_buffer_under_io(struct extent_buffer *eb)
4378 4379 4380 4381 4382 4383 4384 4385 4386 4387 4388 4389 4390 4391 4392 4393 4394 4395 4396 4397 4398 4399 4400 4401 4402 4403 4404 4405 4406 4407 4408 4409 4410 4411 4412 4413 4414 4415 4416 4417 4418 4419 4420 4421 4422 4423 4424 4425 4426 4427 4428 4429 4430 4431 4432 4433 4434 4435 4436 4437 4438 4439 4440 4441 4442 4443 4444 4445 4446
{
	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);
}

4447 4448 4449
static struct extent_buffer *
__alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
		      unsigned long len, gfp_t mask)
4450 4451 4452 4453
{
	struct extent_buffer *eb = NULL;

	eb = kmem_cache_zalloc(extent_buffer_cache, mask);
T
Tsutomu Itoh 已提交
4454 4455
	if (eb == NULL)
		return NULL;
4456 4457
	eb->start = start;
	eb->len = len;
4458
	eb->fs_info = fs_info;
4459
	eb->bflags = 0;
4460 4461 4462 4463 4464 4465 4466
	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);
4467
	eb->lock_nested = 0;
4468 4469
	init_waitqueue_head(&eb->write_lock_wq);
	init_waitqueue_head(&eb->read_lock_wq);
4470

4471 4472
	btrfs_leak_debug_add(&eb->leak_list, &buffers);

4473
	spin_lock_init(&eb->refs_lock);
4474
	atomic_set(&eb->refs, 1);
4475
	atomic_set(&eb->io_pages, 0);
4476

4477 4478 4479 4480 4481 4482
	/*
	 * 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);
4483 4484 4485 4486

	return eb;
}

4487 4488 4489 4490 4491 4492 4493
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);

4494
	new = __alloc_extent_buffer(NULL, src->start, src->len, GFP_NOFS);
4495 4496 4497 4498
	if (new == NULL)
		return NULL;

	for (i = 0; i < num_pages; i++) {
4499
		p = alloc_page(GFP_NOFS);
4500 4501 4502 4503
		if (!p) {
			btrfs_release_extent_buffer(new);
			return NULL;
		}
4504 4505 4506 4507 4508 4509 4510 4511 4512 4513 4514 4515 4516 4517 4518 4519 4520 4521 4522
		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;

4523
	eb = __alloc_extent_buffer(NULL, start, len, GFP_NOFS);
4524 4525 4526 4527
	if (!eb)
		return NULL;

	for (i = 0; i < num_pages; i++) {
4528
		eb->pages[i] = alloc_page(GFP_NOFS);
4529 4530 4531 4532 4533 4534 4535 4536 4537
		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:
4538 4539
	for (; i > 0; i--)
		__free_page(eb->pages[i - 1]);
4540 4541 4542 4543
	__free_extent_buffer(eb);
	return NULL;
}

4544 4545
static void check_buffer_tree_ref(struct extent_buffer *eb)
{
4546
	int refs;
4547 4548 4549 4550 4551 4552 4553 4554 4555 4556 4557 4558 4559 4560 4561 4562 4563 4564 4565 4566
	/* 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.
	 */
4567 4568 4569 4570
	refs = atomic_read(&eb->refs);
	if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
		return;

4571 4572
	spin_lock(&eb->refs_lock);
	if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4573
		atomic_inc(&eb->refs);
4574
	spin_unlock(&eb->refs_lock);
4575 4576
}

4577 4578
static void mark_extent_buffer_accessed(struct extent_buffer *eb,
		struct page *accessed)
4579 4580 4581
{
	unsigned long num_pages, i;

4582 4583
	check_buffer_tree_ref(eb);

4584 4585 4586
	num_pages = num_extent_pages(eb->start, eb->len);
	for (i = 0; i < num_pages; i++) {
		struct page *p = extent_buffer_page(eb, i);
4587 4588
		if (p != accessed)
			mark_page_accessed(p);
4589 4590 4591
	}
}

4592 4593
struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
					 u64 start)
4594 4595 4596 4597
{
	struct extent_buffer *eb;

	rcu_read_lock();
4598 4599
	eb = radix_tree_lookup(&fs_info->buffer_radix,
			       start >> PAGE_CACHE_SHIFT);
4600 4601
	if (eb && atomic_inc_not_zero(&eb->refs)) {
		rcu_read_unlock();
4602
		mark_extent_buffer_accessed(eb, NULL);
4603 4604 4605 4606 4607 4608 4609
		return eb;
	}
	rcu_read_unlock();

	return NULL;
}

4610 4611 4612 4613 4614 4615 4616 4617 4618 4619 4620 4621 4622 4623 4624 4625 4626 4627 4628 4629 4630 4631 4632 4633 4634 4635 4636 4637 4638 4639 4640 4641 4642 4643 4644 4645 4646 4647 4648 4649 4650 4651 4652 4653 4654 4655 4656
#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

4657
struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
4658
					  u64 start, unsigned long len)
4659 4660 4661 4662 4663
{
	unsigned long num_pages = num_extent_pages(start, len);
	unsigned long i;
	unsigned long index = start >> PAGE_CACHE_SHIFT;
	struct extent_buffer *eb;
4664
	struct extent_buffer *exists = NULL;
4665
	struct page *p;
4666
	struct address_space *mapping = fs_info->btree_inode->i_mapping;
4667
	int uptodate = 1;
4668
	int ret;
4669

4670
	eb = find_extent_buffer(fs_info, start);
4671
	if (eb)
4672 4673
		return eb;

4674
	eb = __alloc_extent_buffer(fs_info, start, len, GFP_NOFS);
4675
	if (!eb)
4676 4677
		return NULL;

4678
	for (i = 0; i < num_pages; i++, index++) {
4679
		p = find_or_create_page(mapping, index, GFP_NOFS);
4680
		if (!p)
4681
			goto free_eb;
J
Josef Bacik 已提交
4682 4683 4684 4685 4686 4687 4688 4689 4690 4691 4692 4693 4694 4695

		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);
4696
				page_cache_release(p);
4697
				mark_extent_buffer_accessed(exists, p);
J
Josef Bacik 已提交
4698 4699 4700
				goto free_eb;
			}

4701
			/*
J
Josef Bacik 已提交
4702 4703 4704 4705
			 * Do this so attach doesn't complain and we need to
			 * drop the ref the old guy had.
			 */
			ClearPagePrivate(p);
4706
			WARN_ON(PageDirty(p));
J
Josef Bacik 已提交
4707
			page_cache_release(p);
4708
		}
J
Josef Bacik 已提交
4709 4710
		attach_extent_buffer_page(eb, p);
		spin_unlock(&mapping->private_lock);
4711
		WARN_ON(PageDirty(p));
4712
		eb->pages[i] = p;
4713 4714
		if (!PageUptodate(p))
			uptodate = 0;
C
Chris Mason 已提交
4715 4716 4717 4718 4719

		/*
		 * see below about how we avoid a nasty race with release page
		 * and why we unlock later
		 */
4720 4721
	}
	if (uptodate)
4722
		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4723
again:
4724 4725 4726 4727
	ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
	if (ret)
		goto free_eb;

4728 4729 4730 4731
	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);
4732
	radix_tree_preload_end();
4733
	if (ret == -EEXIST) {
4734
		exists = find_extent_buffer(fs_info, start);
4735 4736 4737
		if (exists)
			goto free_eb;
		else
4738
			goto again;
4739 4740
	}
	/* add one reference for the tree */
4741
	check_buffer_tree_ref(eb);
4742
	set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
C
Chris Mason 已提交
4743 4744 4745 4746 4747 4748 4749 4750 4751 4752

	/*
	 * 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
	 */
4753 4754 4755 4756 4757 4758 4759
	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]);
4760 4761
	return eb;

4762
free_eb:
4763 4764 4765 4766
	for (i = 0; i < num_pages; i++) {
		if (eb->pages[i])
			unlock_page(eb->pages[i]);
	}
C
Chris Mason 已提交
4767

4768
	WARN_ON(!atomic_dec_and_test(&eb->refs));
4769
	btrfs_release_extent_buffer(eb);
4770
	return exists;
4771 4772
}

4773 4774 4775 4776 4777 4778 4779 4780 4781
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 */
4782
static int release_extent_buffer(struct extent_buffer *eb)
4783 4784 4785
{
	WARN_ON(atomic_read(&eb->refs) == 0);
	if (atomic_dec_and_test(&eb->refs)) {
4786
		if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
4787
			struct btrfs_fs_info *fs_info = eb->fs_info;
4788

4789
			spin_unlock(&eb->refs_lock);
4790

4791 4792
			spin_lock(&fs_info->buffer_lock);
			radix_tree_delete(&fs_info->buffer_radix,
4793
					  eb->start >> PAGE_CACHE_SHIFT);
4794
			spin_unlock(&fs_info->buffer_lock);
4795 4796
		} else {
			spin_unlock(&eb->refs_lock);
4797
		}
4798 4799 4800 4801

		/* 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);
4802
		return 1;
4803 4804
	}
	spin_unlock(&eb->refs_lock);
4805 4806

	return 0;
4807 4808
}

4809 4810
void free_extent_buffer(struct extent_buffer *eb)
{
4811 4812
	int refs;
	int old;
4813 4814 4815
	if (!eb)
		return;

4816 4817 4818 4819 4820 4821 4822 4823 4824
	while (1) {
		refs = atomic_read(&eb->refs);
		if (refs <= 3)
			break;
		old = atomic_cmpxchg(&eb->refs, refs, refs - 1);
		if (old == refs)
			return;
	}

4825
	spin_lock(&eb->refs_lock);
4826 4827 4828 4829
	if (atomic_read(&eb->refs) == 2 &&
	    test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))
		atomic_dec(&eb->refs);

4830 4831
	if (atomic_read(&eb->refs) == 2 &&
	    test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
4832
	    !extent_buffer_under_io(eb) &&
4833 4834 4835 4836 4837 4838 4839
	    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.
	 */
4840
	release_extent_buffer(eb);
4841 4842 4843 4844 4845
}

void free_extent_buffer_stale(struct extent_buffer *eb)
{
	if (!eb)
4846 4847
		return;

4848 4849 4850
	spin_lock(&eb->refs_lock);
	set_bit(EXTENT_BUFFER_STALE, &eb->bflags);

4851
	if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
4852 4853
	    test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
		atomic_dec(&eb->refs);
4854
	release_extent_buffer(eb);
4855 4856
}

4857
void clear_extent_buffer_dirty(struct extent_buffer *eb)
4858 4859 4860 4861 4862 4863 4864 4865 4866
{
	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);
4867
		if (!PageDirty(page))
C
Chris Mason 已提交
4868 4869
			continue;

4870
		lock_page(page);
C
Chris Mason 已提交
4871 4872
		WARN_ON(!PagePrivate(page));

4873
		clear_page_dirty_for_io(page);
4874
		spin_lock_irq(&page->mapping->tree_lock);
4875 4876 4877 4878 4879
		if (!PageDirty(page)) {
			radix_tree_tag_clear(&page->mapping->page_tree,
						page_index(page),
						PAGECACHE_TAG_DIRTY);
		}
4880
		spin_unlock_irq(&page->mapping->tree_lock);
4881
		ClearPageError(page);
4882
		unlock_page(page);
4883
	}
4884
	WARN_ON(atomic_read(&eb->refs) == 0);
4885 4886
}

4887
int set_extent_buffer_dirty(struct extent_buffer *eb)
4888 4889 4890
{
	unsigned long i;
	unsigned long num_pages;
4891
	int was_dirty = 0;
4892

4893 4894
	check_buffer_tree_ref(eb);

4895
	was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
4896

4897
	num_pages = num_extent_pages(eb->start, eb->len);
4898
	WARN_ON(atomic_read(&eb->refs) == 0);
4899 4900
	WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));

4901
	for (i = 0; i < num_pages; i++)
4902
		set_page_dirty(extent_buffer_page(eb, i));
4903
	return was_dirty;
4904 4905
}

4906
int clear_extent_buffer_uptodate(struct extent_buffer *eb)
4907 4908 4909 4910 4911
{
	unsigned long i;
	struct page *page;
	unsigned long num_pages;

4912
	clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4913
	num_pages = num_extent_pages(eb->start, eb->len);
4914 4915
	for (i = 0; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
C
Chris Mason 已提交
4916 4917
		if (page)
			ClearPageUptodate(page);
4918 4919 4920 4921
	}
	return 0;
}

4922
int set_extent_buffer_uptodate(struct extent_buffer *eb)
4923 4924 4925 4926 4927
{
	unsigned long i;
	struct page *page;
	unsigned long num_pages;

4928
	set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4929 4930 4931 4932 4933 4934 4935 4936
	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;
}

4937
int extent_buffer_uptodate(struct extent_buffer *eb)
4938
{
4939
	return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4940 4941 4942
}

int read_extent_buffer_pages(struct extent_io_tree *tree,
4943
			     struct extent_buffer *eb, u64 start, int wait,
4944
			     get_extent_t *get_extent, int mirror_num)
4945 4946 4947 4948 4949 4950
{
	unsigned long i;
	unsigned long start_i;
	struct page *page;
	int err;
	int ret = 0;
4951 4952
	int locked_pages = 0;
	int all_uptodate = 1;
4953
	unsigned long num_pages;
4954
	unsigned long num_reads = 0;
4955
	struct bio *bio = NULL;
C
Chris Mason 已提交
4956
	unsigned long bio_flags = 0;
4957

4958
	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
4959 4960 4961 4962 4963 4964 4965 4966 4967 4968 4969 4970 4971
		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);
4972
		if (wait == WAIT_NONE) {
4973
			if (!trylock_page(page))
4974
				goto unlock_exit;
4975 4976 4977
		} else {
			lock_page(page);
		}
4978
		locked_pages++;
4979 4980
		if (!PageUptodate(page)) {
			num_reads++;
4981
			all_uptodate = 0;
4982
		}
4983 4984 4985
	}
	if (all_uptodate) {
		if (start_i == 0)
4986
			set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4987 4988 4989
		goto unlock_exit;
	}

4990
	clear_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
4991
	eb->read_mirror = 0;
4992
	atomic_set(&eb->io_pages, num_reads);
4993 4994 4995
	for (i = start_i; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
		if (!PageUptodate(page)) {
4996
			ClearPageError(page);
4997
			err = __extent_read_full_page(tree, page,
4998
						      get_extent, &bio,
4999 5000
						      mirror_num, &bio_flags,
						      READ | REQ_META);
C
Chris Mason 已提交
5001
			if (err)
5002 5003 5004 5005 5006 5007
				ret = err;
		} else {
			unlock_page(page);
		}
	}

5008
	if (bio) {
5009 5010
		err = submit_one_bio(READ | REQ_META, bio, mirror_num,
				     bio_flags);
5011 5012
		if (err)
			return err;
5013
	}
5014

5015
	if (ret || wait != WAIT_COMPLETE)
5016
		return ret;
C
Chris Mason 已提交
5017

5018 5019 5020
	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
5021
		if (!PageUptodate(page))
5022 5023
			ret = -EIO;
	}
C
Chris Mason 已提交
5024

5025
	return ret;
5026 5027 5028

unlock_exit:
	i = start_i;
C
Chris Mason 已提交
5029
	while (locked_pages > 0) {
5030 5031 5032 5033 5034 5035
		page = extent_buffer_page(eb, i);
		i++;
		unlock_page(page);
		locked_pages--;
	}
	return ret;
5036 5037 5038 5039 5040 5041 5042 5043 5044 5045 5046 5047 5048 5049 5050 5051 5052
}

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);

5053
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5054

C
Chris Mason 已提交
5055
	while (len > 0) {
5056 5057 5058
		page = extent_buffer_page(eb, i);

		cur = min(len, (PAGE_CACHE_SIZE - offset));
5059
		kaddr = page_address(page);
5060 5061 5062 5063 5064 5065 5066 5067 5068
		memcpy(dst, kaddr + offset, cur);

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

5069 5070 5071 5072 5073 5074 5075 5076 5077 5078 5079 5080 5081 5082 5083 5084 5085 5086 5087 5088 5089 5090 5091 5092 5093 5094 5095 5096 5097 5098 5099 5100 5101 5102 5103 5104 5105
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;
}

5106
int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
5107
			       unsigned long min_len, char **map,
5108
			       unsigned long *map_start,
5109
			       unsigned long *map_len)
5110 5111 5112 5113 5114 5115 5116 5117 5118 5119 5120 5121 5122 5123 5124 5125 5126 5127 5128
{
	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
5129

5130
	if (start + min_len > eb->len) {
J
Julia Lawall 已提交
5131
		WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
5132 5133
		       "wanted %lu %lu\n",
		       eb->start, eb->len, start, min_len);
5134
		return -EINVAL;
5135 5136 5137
	}

	p = extent_buffer_page(eb, i);
5138
	kaddr = page_address(p);
5139 5140 5141 5142 5143 5144 5145 5146 5147 5148 5149 5150 5151 5152 5153 5154 5155 5156 5157 5158 5159
	*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);

5160
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5161

C
Chris Mason 已提交
5162
	while (len > 0) {
5163 5164 5165 5166
		page = extent_buffer_page(eb, i);

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

5167
		kaddr = page_address(page);
5168 5169 5170 5171 5172 5173 5174 5175 5176 5177 5178 5179 5180 5181 5182 5183 5184 5185 5186 5187 5188 5189 5190 5191 5192 5193
		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);

5194
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5195

C
Chris Mason 已提交
5196
	while (len > 0) {
5197 5198 5199 5200
		page = extent_buffer_page(eb, i);
		WARN_ON(!PageUptodate(page));

		cur = min(len, PAGE_CACHE_SIZE - offset);
5201
		kaddr = page_address(page);
5202 5203 5204 5205 5206 5207 5208 5209 5210 5211 5212 5213 5214 5215 5216 5217 5218 5219 5220 5221 5222 5223
		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);

5224
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5225

C
Chris Mason 已提交
5226
	while (len > 0) {
5227 5228 5229 5230
		page = extent_buffer_page(eb, i);
		WARN_ON(!PageUptodate(page));

		cur = min(len, PAGE_CACHE_SIZE - offset);
5231
		kaddr = page_address(page);
5232 5233 5234 5235 5236 5237 5238 5239 5240 5241 5242 5243 5244 5245 5246 5247 5248 5249 5250 5251 5252 5253 5254
		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) &
5255
		(PAGE_CACHE_SIZE - 1);
5256

C
Chris Mason 已提交
5257
	while (len > 0) {
5258 5259 5260 5261 5262
		page = extent_buffer_page(dst, i);
		WARN_ON(!PageUptodate(page));

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

5263
		kaddr = page_address(page);
5264 5265 5266 5267 5268 5269 5270 5271 5272
		read_extent_buffer(src, kaddr + offset, src_offset, cur);

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

5273 5274 5275 5276 5277 5278
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;
}

5279 5280 5281 5282
static void copy_pages(struct page *dst_page, struct page *src_page,
		       unsigned long dst_off, unsigned long src_off,
		       unsigned long len)
{
5283
	char *dst_kaddr = page_address(dst_page);
5284
	char *src_kaddr;
5285
	int must_memmove = 0;
5286

5287
	if (dst_page != src_page) {
5288
		src_kaddr = page_address(src_page);
5289
	} else {
5290
		src_kaddr = dst_kaddr;
5291 5292
		if (areas_overlap(src_off, dst_off, len))
			must_memmove = 1;
5293
	}
5294

5295 5296 5297 5298
	if (must_memmove)
		memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
	else
		memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
5299 5300 5301 5302 5303 5304 5305 5306 5307 5308 5309 5310 5311
}

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) {
5312
		printk(KERN_ERR "BTRFS: memmove bogus src_offset %lu move "
C
Chris Mason 已提交
5313
		       "len %lu dst len %lu\n", src_offset, len, dst->len);
5314 5315 5316
		BUG_ON(1);
	}
	if (dst_offset + len > dst->len) {
5317
		printk(KERN_ERR "BTRFS: memmove bogus dst_offset %lu move "
C
Chris Mason 已提交
5318
		       "len %lu dst len %lu\n", dst_offset, len, dst->len);
5319 5320 5321
		BUG_ON(1);
	}

C
Chris Mason 已提交
5322
	while (len > 0) {
5323
		dst_off_in_page = (start_offset + dst_offset) &
5324
			(PAGE_CACHE_SIZE - 1);
5325
		src_off_in_page = (start_offset + src_offset) &
5326
			(PAGE_CACHE_SIZE - 1);
5327 5328 5329 5330 5331 5332 5333 5334 5335 5336 5337 5338 5339 5340 5341 5342 5343 5344 5345 5346 5347 5348 5349 5350 5351 5352 5353 5354 5355 5356 5357 5358

		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) {
5359
		printk(KERN_ERR "BTRFS: memmove bogus src_offset %lu move "
C
Chris Mason 已提交
5360
		       "len %lu len %lu\n", src_offset, len, dst->len);
5361 5362 5363
		BUG_ON(1);
	}
	if (dst_offset + len > dst->len) {
5364
		printk(KERN_ERR "BTRFS: memmove bogus dst_offset %lu move "
C
Chris Mason 已提交
5365
		       "len %lu len %lu\n", dst_offset, len, dst->len);
5366 5367
		BUG_ON(1);
	}
5368
	if (dst_offset < src_offset) {
5369 5370 5371
		memcpy_extent_buffer(dst, dst_offset, src_offset, len);
		return;
	}
C
Chris Mason 已提交
5372
	while (len > 0) {
5373 5374 5375 5376
		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) &
5377
			(PAGE_CACHE_SIZE - 1);
5378
		src_off_in_page = (start_offset + src_end) &
5379
			(PAGE_CACHE_SIZE - 1);
5380 5381 5382

		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
5383
		copy_pages(extent_buffer_page(dst, dst_i),
5384 5385 5386 5387 5388 5389 5390 5391 5392
			   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;
	}
}
5393

5394
int try_release_extent_buffer(struct page *page)
5395
{
5396 5397
	struct extent_buffer *eb;

5398 5399 5400 5401 5402 5403 5404
	/*
	 * 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
5405
		return 1;
5406
	}
5407

5408 5409
	eb = (struct extent_buffer *)page->private;
	BUG_ON(!eb);
5410 5411

	/*
5412 5413 5414
	 * 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.
5415
	 */
5416
	spin_lock(&eb->refs_lock);
5417
	if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
5418 5419 5420
		spin_unlock(&eb->refs_lock);
		spin_unlock(&page->mapping->private_lock);
		return 0;
5421
	}
5422
	spin_unlock(&page->mapping->private_lock);
5423

5424
	/*
5425 5426
	 * 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.
5427
	 */
5428 5429 5430
	if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
		spin_unlock(&eb->refs_lock);
		return 0;
5431
	}
5432

5433
	return release_extent_buffer(eb);
5434
}