extent_io.c 132.8 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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28
#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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		printk(KERN_ERR "BTRFS: state leak: start %llu end %llu "
63
		       "state %lu in tree %p refs %d\n",
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		       state->start, state->end, state->state, state->tree,
		       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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80 81
#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,
83
		struct extent_io_tree *tree, u64 start, u64 end)
84
{
85 86
	struct inode *inode;
	u64 isize;
87

88 89
	if (!tree->mapping)
		return;
90

91 92
	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",
96
				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)
195
{
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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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	state->tree = NULL;
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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(state->tree);
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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)
325
{
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	struct rb_node *prev = NULL;
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	struct rb_node *ret;
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329
	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;

364
	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;
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			other->tree = NULL;
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			rb_erase(&other->rb_node, &tree->state);
			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;
			other->tree = NULL;
			rb_erase(&other->rb_node, &tree->state);
			free_extent_state(other);
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		}
	}
}

393
static void set_state_cb(struct extent_io_tree *tree,
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			 struct extent_state *state, unsigned long *bits)
395
{
396 397
	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,
401
			   struct extent_state *state, unsigned long *bits)
402
{
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	if (tree->ops && tree->ops->clear_bit_hook)
		tree->ops->clear_bit_hook(tree->mapping->host, state, bits);
405 406
}

407
static void set_state_bits(struct extent_io_tree *tree,
408
			   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,
422 423
			struct rb_node ***p,
			struct rb_node **parent,
424
			unsigned long *bits)
425 426 427
{
	struct rb_node *node;

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	if (end < start)
429
		WARN(1, KERN_ERR "BTRFS: end < start %llu %llu\n",
430
		       end, start);
431 432
	state->start = start;
	state->end = end;
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434 435
	set_state_bits(tree, state, bits);

436
	node = tree_insert(&tree->state, NULL, end, &state->rb_node, p, parent);
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	if (node) {
		struct extent_state *found;
		found = rb_entry(node, struct extent_state, rb_node);
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		printk(KERN_ERR "BTRFS: found node %llu %llu on insert of "
441 442
		       "%llu %llu\n",
		       found->start, found->end, start, end);
443 444
		return -EEXIST;
	}
445
	state->tree = tree;
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	merge_state(tree, state);
	return 0;
}

450
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)
454
		tree->ops->split_extent_hook(tree->mapping->host, orig, split);
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}

457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474
/*
 * 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);

478 479 480 481 482
	prealloc->start = orig->start;
	prealloc->end = split - 1;
	prealloc->state = orig->state;
	orig->start = split;

483 484
	node = tree_insert(&tree->state, &orig->rb_node, prealloc->end,
			   &prealloc->rb_node, NULL, NULL);
485 486 487 488
	if (node) {
		free_extent_state(prealloc);
		return -EEXIST;
	}
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	prealloc->tree = tree;
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	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.
504
 * 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,
511
					    unsigned long *bits, int wake)
512
{
513
	struct extent_state *next;
514
	unsigned long bits_to_clear = *bits & ~EXTENT_CTLBITS;
515

516
	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;
	}
521
	clear_state_cb(tree, state, bits);
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	state->state &= ~bits_to_clear;
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	if (wake)
		wake_up(&state->wq);
525
	if (state->state == 0) {
526
		next = next_state(state);
527
		if (state->tree) {
528
			rb_erase(&state->rb_node, &tree->state);
529
			state->tree = NULL;
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			free_extent_state(state);
		} else {
			WARN_ON(1);
		}
	} else {
		merge_state(tree, state);
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		next = next_state(state);
537
	}
538
	return next;
539 540
}

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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;
}

550
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.
 *
567
 * 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,
570
		     unsigned long bits, int wake, int delete,
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		     struct extent_state **cached_state,
		     gfp_t mask)
573 574
{
	struct extent_state *state;
575
	struct extent_state *cached;
576 577
	struct extent_state *prealloc = NULL;
	struct rb_node *node;
578
	u64 last_end;
579
	int err;
580
	int clear = 0;
581

582
	btrfs_debug_check_extent_io_range(tree, start, end);
583

584 585 586
	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;
	}

600
	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;
		}

609 610
		if (cached && cached->tree && cached->start <= start &&
		    cached->end > start) {
611 612
			if (clear)
				atomic_dec(&cached->refs);
613
			state = cached;
614
			goto hit_next;
615
		}
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		if (clear)
			free_extent_state(cached);
618
	}
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	/*
	 * this search will find the extents that end after
	 * our range starts
	 */
623
	node = tree_search(tree, start);
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	if (!node)
		goto out;
	state = rb_entry(node, struct extent_state, rb_node);
627
hit_next:
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	if (state->start > end)
		goto out;
	WARN_ON(state->end < start);
631
	last_end = state->end;
632

633
	/* the state doesn't have the wanted bits, go ahead */
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	if (!(state->state & bits)) {
		state = next_state(state);
636
		goto next;
637
	}
638

639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655
	/*
	 *     | ---- 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) {
656 657
		prealloc = alloc_extent_state_atomic(prealloc);
		BUG_ON(!prealloc);
658
		err = split_state(tree, state, prealloc, start);
659 660 661
		if (err)
			extent_io_tree_panic(tree, err);

662 663 664 665
		prealloc = NULL;
		if (err)
			goto out;
		if (state->end <= end) {
666 667
			state = clear_state_bit(tree, state, &bits, wake);
			goto next;
668 669 670 671 672 673 674 675 676 677
		}
		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) {
678 679
		prealloc = alloc_extent_state_atomic(prealloc);
		BUG_ON(!prealloc);
680
		err = split_state(tree, state, prealloc, end + 1);
681 682 683
		if (err)
			extent_io_tree_panic(tree, err);

684 685
		if (wake)
			wake_up(&state->wq);
686

687
		clear_state_bit(tree, prealloc, &bits, wake);
J
Josef Bacik 已提交
688

689 690 691
		prealloc = NULL;
		goto out;
	}
692

693
	state = clear_state_bit(tree, state, &bits, wake);
694
next:
695 696 697
	if (last_end == (u64)-1)
		goto out;
	start = last_end + 1;
698
	if (start <= end && state && !need_resched())
699
		goto hit_next;
700 701 702
	goto search_again;

out:
703
	spin_unlock(&tree->lock);
704 705 706
	if (prealloc)
		free_extent_state(prealloc);

707
	return 0;
708 709 710 711

search_again:
	if (start > end)
		goto out;
712
	spin_unlock(&tree->lock);
713 714 715 716 717
	if (mask & __GFP_WAIT)
		cond_resched();
	goto again;
}

718 719
static void wait_on_state(struct extent_io_tree *tree,
			  struct extent_state *state)
720 721
		__releases(tree->lock)
		__acquires(tree->lock)
722 723 724
{
	DEFINE_WAIT(wait);
	prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
725
	spin_unlock(&tree->lock);
726
	schedule();
727
	spin_lock(&tree->lock);
728 729 730 731 732 733 734 735
	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
 */
736 737
static void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
			    unsigned long bits)
738 739 740 741
{
	struct extent_state *state;
	struct rb_node *node;

742
	btrfs_debug_check_extent_io_range(tree, start, end);
743

744
	spin_lock(&tree->lock);
745 746 747 748 749 750
again:
	while (1) {
		/*
		 * this search will find all the extents that end after
		 * our range starts
		 */
751
		node = tree_search(tree, start);
752
process_node:
753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772
		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;

773 774 775 776
		if (!cond_resched_lock(&tree->lock)) {
			node = rb_next(node);
			goto process_node;
		}
777 778
	}
out:
779
	spin_unlock(&tree->lock);
780 781
}

782
static void set_state_bits(struct extent_io_tree *tree,
783
			   struct extent_state *state,
784
			   unsigned long *bits)
785
{
786
	unsigned long bits_to_set = *bits & ~EXTENT_CTLBITS;
J
Josef Bacik 已提交
787

788
	set_state_cb(tree, state, bits);
789
	if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
790 791 792
		u64 range = state->end - state->start + 1;
		tree->dirty_bytes += range;
	}
793
	state->state |= bits_to_set;
794 795
}

796 797 798 799 800 801 802 803 804 805 806
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);
		}
	}
}

807
/*
808 809
 * 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.
810
 *
811 812 813
 * 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.
814
 *
815
 * [start, end] is inclusive This takes the tree lock.
816
 */
817

J
Jeff Mahoney 已提交
818 819
static int __must_check
__set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
820 821 822
		 unsigned long bits, unsigned long exclusive_bits,
		 u64 *failed_start, struct extent_state **cached_state,
		 gfp_t mask)
823 824 825 826
{
	struct extent_state *state;
	struct extent_state *prealloc = NULL;
	struct rb_node *node;
827 828
	struct rb_node **p;
	struct rb_node *parent;
829 830 831
	int err = 0;
	u64 last_start;
	u64 last_end;
832

833
	btrfs_debug_check_extent_io_range(tree, start, end);
834

835
	bits |= EXTENT_FIRST_DELALLOC;
836 837 838
again:
	if (!prealloc && (mask & __GFP_WAIT)) {
		prealloc = alloc_extent_state(mask);
839
		BUG_ON(!prealloc);
840 841
	}

842
	spin_lock(&tree->lock);
843 844
	if (cached_state && *cached_state) {
		state = *cached_state;
845 846
		if (state->start <= start && state->end > start &&
		    state->tree) {
847 848 849 850
			node = &state->rb_node;
			goto hit_next;
		}
	}
851 852 853 854
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
855
	node = tree_search_for_insert(tree, start, &p, &parent);
856
	if (!node) {
857 858
		prealloc = alloc_extent_state_atomic(prealloc);
		BUG_ON(!prealloc);
859 860
		err = insert_state(tree, prealloc, start, end,
				   &p, &parent, &bits);
861 862 863
		if (err)
			extent_io_tree_panic(tree, err);

864
		cache_state(prealloc, cached_state);
865 866 867 868
		prealloc = NULL;
		goto out;
	}
	state = rb_entry(node, struct extent_state, rb_node);
C
Chris Mason 已提交
869
hit_next:
870 871 872 873 874 875 876 877 878 879
	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) {
880
		if (state->state & exclusive_bits) {
881 882 883 884
			*failed_start = state->start;
			err = -EEXIST;
			goto out;
		}
885

886
		set_state_bits(tree, state, &bits);
887
		cache_state(state, cached_state);
888
		merge_state(tree, state);
889 890 891
		if (last_end == (u64)-1)
			goto out;
		start = last_end + 1;
892 893 894 895
		state = next_state(state);
		if (start < end && state && state->start == start &&
		    !need_resched())
			goto hit_next;
896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915
		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) {
916
		if (state->state & exclusive_bits) {
917 918 919 920
			*failed_start = start;
			err = -EEXIST;
			goto out;
		}
921 922 923

		prealloc = alloc_extent_state_atomic(prealloc);
		BUG_ON(!prealloc);
924
		err = split_state(tree, state, prealloc, start);
925 926 927
		if (err)
			extent_io_tree_panic(tree, err);

928 929 930 931
		prealloc = NULL;
		if (err)
			goto out;
		if (state->end <= end) {
932
			set_state_bits(tree, state, &bits);
933
			cache_state(state, cached_state);
934
			merge_state(tree, state);
935 936 937
			if (last_end == (u64)-1)
				goto out;
			start = last_end + 1;
938 939 940 941
			state = next_state(state);
			if (start < end && state && state->start == start &&
			    !need_resched())
				goto hit_next;
942 943 944 945 946 947 948 949 950 951 952 953 954 955 956
		}
		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
957
			this_end = last_start - 1;
958 959 960

		prealloc = alloc_extent_state_atomic(prealloc);
		BUG_ON(!prealloc);
961 962 963 964 965

		/*
		 * Avoid to free 'prealloc' if it can be merged with
		 * the later extent.
		 */
966
		err = insert_state(tree, prealloc, start, this_end,
967
				   NULL, NULL, &bits);
968 969 970
		if (err)
			extent_io_tree_panic(tree, err);

J
Josef Bacik 已提交
971 972
		cache_state(prealloc, cached_state);
		prealloc = NULL;
973 974 975 976 977 978 979 980 981 982
		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) {
983
		if (state->state & exclusive_bits) {
984 985 986 987
			*failed_start = start;
			err = -EEXIST;
			goto out;
		}
988 989 990

		prealloc = alloc_extent_state_atomic(prealloc);
		BUG_ON(!prealloc);
991
		err = split_state(tree, state, prealloc, end + 1);
992 993
		if (err)
			extent_io_tree_panic(tree, err);
994

995
		set_state_bits(tree, prealloc, &bits);
996
		cache_state(prealloc, cached_state);
997 998 999 1000 1001 1002 1003 1004
		merge_state(tree, prealloc);
		prealloc = NULL;
		goto out;
	}

	goto search_again;

out:
1005
	spin_unlock(&tree->lock);
1006 1007 1008 1009 1010 1011 1012 1013
	if (prealloc)
		free_extent_state(prealloc);

	return err;

search_again:
	if (start > end)
		goto out;
1014
	spin_unlock(&tree->lock);
1015 1016 1017 1018 1019
	if (mask & __GFP_WAIT)
		cond_resched();
	goto again;
}

1020 1021 1022
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
1023 1024 1025 1026 1027 1028
{
	return __set_extent_bit(tree, start, end, bits, 0, failed_start,
				cached_state, mask);
}


J
Josef Bacik 已提交
1029
/**
L
Liu Bo 已提交
1030 1031
 * convert_extent_bit - convert all bits in a given range from one bit to
 * 			another
J
Josef Bacik 已提交
1032 1033 1034 1035 1036
 * @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
1037
 * @cached_state:	state that we're going to cache
J
Josef Bacik 已提交
1038 1039 1040 1041 1042 1043 1044 1045 1046
 * @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,
1047
		       unsigned long bits, unsigned long clear_bits,
1048
		       struct extent_state **cached_state, gfp_t mask)
J
Josef Bacik 已提交
1049 1050 1051 1052
{
	struct extent_state *state;
	struct extent_state *prealloc = NULL;
	struct rb_node *node;
1053 1054
	struct rb_node **p;
	struct rb_node *parent;
J
Josef Bacik 已提交
1055 1056 1057 1058
	int err = 0;
	u64 last_start;
	u64 last_end;

1059
	btrfs_debug_check_extent_io_range(tree, start, end);
1060

J
Josef Bacik 已提交
1061 1062 1063 1064 1065 1066 1067 1068
again:
	if (!prealloc && (mask & __GFP_WAIT)) {
		prealloc = alloc_extent_state(mask);
		if (!prealloc)
			return -ENOMEM;
	}

	spin_lock(&tree->lock);
1069 1070 1071 1072 1073 1074 1075 1076 1077
	if (cached_state && *cached_state) {
		state = *cached_state;
		if (state->start <= start && state->end > start &&
		    state->tree) {
			node = &state->rb_node;
			goto hit_next;
		}
	}

J
Josef Bacik 已提交
1078 1079 1080 1081
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1082
	node = tree_search_for_insert(tree, start, &p, &parent);
J
Josef Bacik 已提交
1083 1084
	if (!node) {
		prealloc = alloc_extent_state_atomic(prealloc);
1085 1086 1087 1088
		if (!prealloc) {
			err = -ENOMEM;
			goto out;
		}
1089 1090
		err = insert_state(tree, prealloc, start, end,
				   &p, &parent, &bits);
1091 1092
		if (err)
			extent_io_tree_panic(tree, err);
1093 1094
		cache_state(prealloc, cached_state);
		prealloc = NULL;
J
Josef Bacik 已提交
1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109
		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);
1110
		cache_state(state, cached_state);
1111
		state = clear_state_bit(tree, state, &clear_bits, 0);
J
Josef Bacik 已提交
1112 1113 1114
		if (last_end == (u64)-1)
			goto out;
		start = last_end + 1;
1115 1116 1117
		if (start < end && state && state->start == start &&
		    !need_resched())
			goto hit_next;
J
Josef Bacik 已提交
1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138
		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);
1139 1140 1141 1142
		if (!prealloc) {
			err = -ENOMEM;
			goto out;
		}
J
Josef Bacik 已提交
1143
		err = split_state(tree, state, prealloc, start);
1144 1145
		if (err)
			extent_io_tree_panic(tree, err);
J
Josef Bacik 已提交
1146 1147 1148 1149 1150
		prealloc = NULL;
		if (err)
			goto out;
		if (state->end <= end) {
			set_state_bits(tree, state, &bits);
1151
			cache_state(state, cached_state);
1152
			state = clear_state_bit(tree, state, &clear_bits, 0);
J
Josef Bacik 已提交
1153 1154 1155
			if (last_end == (u64)-1)
				goto out;
			start = last_end + 1;
1156 1157 1158
			if (start < end && state && state->start == start &&
			    !need_resched())
				goto hit_next;
J
Josef Bacik 已提交
1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176
		}
		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);
1177 1178 1179 1180
		if (!prealloc) {
			err = -ENOMEM;
			goto out;
		}
J
Josef Bacik 已提交
1181 1182 1183 1184 1185 1186

		/*
		 * Avoid to free 'prealloc' if it can be merged with
		 * the later extent.
		 */
		err = insert_state(tree, prealloc, start, this_end,
1187
				   NULL, NULL, &bits);
1188 1189
		if (err)
			extent_io_tree_panic(tree, err);
1190
		cache_state(prealloc, cached_state);
J
Josef Bacik 已提交
1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202
		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);
1203 1204 1205 1206
		if (!prealloc) {
			err = -ENOMEM;
			goto out;
		}
J
Josef Bacik 已提交
1207 1208

		err = split_state(tree, state, prealloc, end + 1);
1209 1210
		if (err)
			extent_io_tree_panic(tree, err);
J
Josef Bacik 已提交
1211 1212

		set_state_bits(tree, prealloc, &bits);
1213
		cache_state(prealloc, cached_state);
J
Josef Bacik 已提交
1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236
		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;
}

1237 1238 1239 1240
/* 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
1241
	return set_extent_bit(tree, start, end, EXTENT_DIRTY, NULL,
1242
			      NULL, mask);
1243 1244 1245
}

int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1246
		    unsigned long bits, gfp_t mask)
1247
{
J
Jeff Mahoney 已提交
1248
	return set_extent_bit(tree, start, end, bits, NULL,
1249
			      NULL, mask);
1250 1251 1252
}

int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1253
		      unsigned long bits, gfp_t mask)
1254
{
1255
	return clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask);
1256 1257 1258
}

int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
1259
			struct extent_state **cached_state, gfp_t mask)
1260 1261
{
	return set_extent_bit(tree, start, end,
1262
			      EXTENT_DELALLOC | EXTENT_UPTODATE,
J
Jeff Mahoney 已提交
1263
			      NULL, cached_state, mask);
1264 1265
}

1266 1267 1268 1269 1270 1271 1272 1273
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);
}

1274 1275 1276 1277
int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
		       gfp_t mask)
{
	return clear_extent_bit(tree, start, end,
1278
				EXTENT_DIRTY | EXTENT_DELALLOC |
1279
				EXTENT_DO_ACCOUNTING, 0, 0, NULL, mask);
1280 1281 1282 1283 1284
}

int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
		     gfp_t mask)
{
J
Jeff Mahoney 已提交
1285
	return set_extent_bit(tree, start, end, EXTENT_NEW, NULL,
1286
			      NULL, mask);
1287 1288 1289
}

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

1296 1297
int clear_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
			  struct extent_state **cached_state, gfp_t mask)
1298
{
1299
	return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
1300
				cached_state, mask);
1301 1302
}

C
Chris Mason 已提交
1303 1304 1305 1306
/*
 * either insert or lock state struct between start and end use mask to tell
 * us if waiting is desired.
 */
1307
int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1308
		     unsigned long bits, struct extent_state **cached_state)
1309 1310 1311 1312
{
	int err;
	u64 failed_start;
	while (1) {
J
Jeff Mahoney 已提交
1313 1314 1315
		err = __set_extent_bit(tree, start, end, EXTENT_LOCKED | bits,
				       EXTENT_LOCKED, &failed_start,
				       cached_state, GFP_NOFS);
1316
		if (err == -EEXIST) {
1317 1318
			wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
			start = failed_start;
1319
		} else
1320 1321 1322 1323 1324 1325
			break;
		WARN_ON(start > end);
	}
	return err;
}

1326
int lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1327
{
1328
	return lock_extent_bits(tree, start, end, 0, NULL);
1329 1330
}

1331
int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1332 1333 1334 1335
{
	int err;
	u64 failed_start;

J
Jeff Mahoney 已提交
1336 1337
	err = __set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
			       &failed_start, NULL, GFP_NOFS);
Y
Yan Zheng 已提交
1338 1339 1340
	if (err == -EEXIST) {
		if (failed_start > start)
			clear_extent_bit(tree, start, failed_start - 1,
1341
					 EXTENT_LOCKED, 1, 0, NULL, GFP_NOFS);
1342
		return 0;
Y
Yan Zheng 已提交
1343
	}
1344 1345 1346
	return 1;
}

1347 1348 1349 1350 1351 1352 1353
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);
}

1354
int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end)
1355
{
1356
	return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
1357
				GFP_NOFS);
1358 1359
}

1360 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
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;
}

1393 1394 1395
/*
 * helper function to set both pages and extents in the tree writeback
 */
1396
static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1397 1398 1399 1400 1401 1402 1403
{
	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);
1404
		BUG_ON(!page); /* Pages should be in the extent_io_tree */
1405 1406 1407 1408 1409 1410 1411
		set_page_writeback(page);
		page_cache_release(page);
		index++;
	}
	return 0;
}

C
Chris Mason 已提交
1412 1413 1414 1415
/* 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'
 */
1416 1417
static struct extent_state *
find_first_extent_bit_state(struct extent_io_tree *tree,
1418
			    u64 start, unsigned long bits)
C
Chris Mason 已提交
1419 1420 1421 1422 1423 1424 1425 1426 1427
{
	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
1428
	if (!node)
C
Chris Mason 已提交
1429 1430
		goto out;

C
Chris Mason 已提交
1431
	while (1) {
C
Chris Mason 已提交
1432
		state = rb_entry(node, struct extent_state, rb_node);
C
Chris Mason 已提交
1433
		if (state->end >= start && (state->state & bits))
C
Chris Mason 已提交
1434
			return state;
C
Chris Mason 已提交
1435

C
Chris Mason 已提交
1436 1437 1438 1439 1440 1441 1442 1443
		node = rb_next(node);
		if (!node)
			break;
	}
out:
	return NULL;
}

1444 1445 1446 1447 1448
/*
 * 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.
 *
1449
 * If nothing was found, 1 is returned. If found something, return 0.
1450 1451
 */
int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
1452
			  u64 *start_ret, u64 *end_ret, unsigned long bits,
1453
			  struct extent_state **cached_state)
1454 1455
{
	struct extent_state *state;
1456
	struct rb_node *n;
1457 1458 1459
	int ret = 1;

	spin_lock(&tree->lock);
1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478
	if (cached_state && *cached_state) {
		state = *cached_state;
		if (state->end == start - 1 && state->tree) {
			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;
	}

1479
	state = find_first_extent_bit_state(tree, start, bits);
1480
got_it:
1481
	if (state) {
1482
		cache_state(state, cached_state);
1483 1484 1485 1486
		*start_ret = state->start;
		*end_ret = state->end;
		ret = 0;
	}
1487
out:
1488 1489 1490 1491
	spin_unlock(&tree->lock);
	return ret;
}

C
Chris Mason 已提交
1492 1493 1494 1495 1496 1497
/*
 * 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
1498
static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1499 1500
					u64 *start, u64 *end, u64 max_bytes,
					struct extent_state **cached_state)
1501 1502 1503 1504 1505 1506 1507
{
	struct rb_node *node;
	struct extent_state *state;
	u64 cur_start = *start;
	u64 found = 0;
	u64 total_bytes = 0;

1508
	spin_lock(&tree->lock);
C
Chris Mason 已提交
1509

1510 1511 1512 1513
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1514
	node = tree_search(tree, cur_start);
1515
	if (!node) {
1516 1517
		if (!found)
			*end = (u64)-1;
1518 1519 1520
		goto out;
	}

C
Chris Mason 已提交
1521
	while (1) {
1522
		state = rb_entry(node, struct extent_state, rb_node);
1523 1524
		if (found && (state->start != cur_start ||
			      (state->state & EXTENT_BOUNDARY))) {
1525 1526 1527 1528 1529 1530 1531
			goto out;
		}
		if (!(state->state & EXTENT_DELALLOC)) {
			if (!found)
				*end = state->end;
			goto out;
		}
1532
		if (!found) {
1533
			*start = state->start;
1534 1535 1536
			*cached_state = state;
			atomic_inc(&state->refs);
		}
1537 1538 1539 1540 1541
		found++;
		*end = state->end;
		cur_start = state->end + 1;
		node = rb_next(node);
		total_bytes += state->end - state->start + 1;
1542
		if (total_bytes >= max_bytes)
1543 1544
			break;
		if (!node)
1545 1546 1547
			break;
	}
out:
1548
	spin_unlock(&tree->lock);
1549 1550 1551
	return found;
}

1552 1553 1554
static noinline void __unlock_for_delalloc(struct inode *inode,
					   struct page *locked_page,
					   u64 start, u64 end)
C
Chris Mason 已提交
1555 1556 1557 1558 1559 1560 1561 1562 1563
{
	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)
1564
		return;
C
Chris Mason 已提交
1565

C
Chris Mason 已提交
1566
	while (nr_pages > 0) {
C
Chris Mason 已提交
1567
		ret = find_get_pages_contig(inode->i_mapping, index,
1568 1569
				     min_t(unsigned long, nr_pages,
				     ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1570 1571 1572 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
		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
1601
	while (nrpages > 0) {
C
Chris Mason 已提交
1602
		ret = find_get_pages_contig(inode->i_mapping, index,
1603 1604
				     min_t(unsigned long,
				     nrpages, ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1605 1606 1607 1608 1609 1610 1611 1612 1613 1614
		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
			 */
1615
			if (pages[i] != locked_page) {
C
Chris Mason 已提交
1616
				lock_page(pages[i]);
1617 1618
				if (!PageDirty(pages[i]) ||
				    pages[i]->mapping != inode->i_mapping) {
1619 1620 1621 1622 1623 1624
					ret = -EAGAIN;
					unlock_page(pages[i]);
					page_cache_release(pages[i]);
					goto done;
				}
			}
C
Chris Mason 已提交
1625
			page_cache_release(pages[i]);
1626
			pages_locked++;
C
Chris Mason 已提交
1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648
		}
		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
 */
1649 1650 1651 1652
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
1653 1654 1655 1656
{
	u64 delalloc_start;
	u64 delalloc_end;
	u64 found;
1657
	struct extent_state *cached_state = NULL;
C
Chris Mason 已提交
1658 1659 1660 1661 1662 1663 1664 1665
	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,
1666
				    max_bytes, &cached_state);
C
Chris Mason 已提交
1667
	if (!found || delalloc_end <= *start) {
C
Chris Mason 已提交
1668 1669
		*start = delalloc_start;
		*end = delalloc_end;
1670
		free_extent_state(cached_state);
L
Liu Bo 已提交
1671
		return 0;
C
Chris Mason 已提交
1672 1673
	}

C
Chris Mason 已提交
1674 1675 1676 1677 1678
	/*
	 * 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
1679
	if (delalloc_start < *start)
C
Chris Mason 已提交
1680 1681
		delalloc_start = *start;

C
Chris Mason 已提交
1682 1683 1684
	/*
	 * make sure to limit the number of pages we try to lock down
	 */
1685 1686
	if (delalloc_end + 1 - delalloc_start > max_bytes)
		delalloc_end = delalloc_start + max_bytes - 1;
C
Chris Mason 已提交
1687

C
Chris Mason 已提交
1688 1689 1690 1691 1692 1693 1694
	/* 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
		 */
1695
		free_extent_state(cached_state);
C
Chris Mason 已提交
1696
		if (!loops) {
1697
			max_bytes = PAGE_CACHE_SIZE;
C
Chris Mason 已提交
1698 1699 1700 1701 1702 1703 1704
			loops = 1;
			goto again;
		} else {
			found = 0;
			goto out_failed;
		}
	}
1705
	BUG_ON(ret); /* Only valid values are 0 and -EAGAIN */
C
Chris Mason 已提交
1706 1707

	/* step three, lock the state bits for the whole range */
1708
	lock_extent_bits(tree, delalloc_start, delalloc_end, 0, &cached_state);
C
Chris Mason 已提交
1709 1710 1711

	/* then test to make sure it is all still delalloc */
	ret = test_range_bit(tree, delalloc_start, delalloc_end,
1712
			     EXTENT_DELALLOC, 1, cached_state);
C
Chris Mason 已提交
1713
	if (!ret) {
1714 1715
		unlock_extent_cached(tree, delalloc_start, delalloc_end,
				     &cached_state, GFP_NOFS);
C
Chris Mason 已提交
1716 1717 1718 1719 1720
		__unlock_for_delalloc(inode, locked_page,
			      delalloc_start, delalloc_end);
		cond_resched();
		goto again;
	}
1721
	free_extent_state(cached_state);
C
Chris Mason 已提交
1722 1723 1724 1725 1726 1727
	*start = delalloc_start;
	*end = delalloc_end;
out_failed:
	return found;
}

1728 1729 1730 1731
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
1732
{
1733
	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
C
Chris Mason 已提交
1734 1735 1736 1737 1738 1739
	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;
1740

1741
	clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1742
	if (page_ops == 0)
1743
		return 0;
C
Chris Mason 已提交
1744

C
Chris Mason 已提交
1745
	while (nr_pages > 0) {
C
Chris Mason 已提交
1746
		ret = find_get_pages_contig(inode->i_mapping, index,
1747 1748
				     min_t(unsigned long,
				     nr_pages, ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1749
		for (i = 0; i < ret; i++) {
1750

1751
			if (page_ops & PAGE_SET_PRIVATE2)
1752 1753
				SetPagePrivate2(pages[i]);

C
Chris Mason 已提交
1754 1755 1756 1757
			if (pages[i] == locked_page) {
				page_cache_release(pages[i]);
				continue;
			}
1758
			if (page_ops & PAGE_CLEAR_DIRTY)
C
Chris Mason 已提交
1759
				clear_page_dirty_for_io(pages[i]);
1760
			if (page_ops & PAGE_SET_WRITEBACK)
C
Chris Mason 已提交
1761
				set_page_writeback(pages[i]);
1762
			if (page_ops & PAGE_END_WRITEBACK)
C
Chris Mason 已提交
1763
				end_page_writeback(pages[i]);
1764
			if (page_ops & PAGE_UNLOCK)
1765
				unlock_page(pages[i]);
C
Chris Mason 已提交
1766 1767 1768 1769 1770 1771 1772 1773 1774
			page_cache_release(pages[i]);
		}
		nr_pages -= ret;
		index += ret;
		cond_resched();
	}
	return 0;
}

C
Chris Mason 已提交
1775 1776 1777 1778 1779
/*
 * 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.
 */
1780 1781
u64 count_range_bits(struct extent_io_tree *tree,
		     u64 *start, u64 search_end, u64 max_bytes,
1782
		     unsigned long bits, int contig)
1783 1784 1785 1786 1787
{
	struct rb_node *node;
	struct extent_state *state;
	u64 cur_start = *start;
	u64 total_bytes = 0;
1788
	u64 last = 0;
1789 1790
	int found = 0;

1791
	if (WARN_ON(search_end <= cur_start))
1792 1793
		return 0;

1794
	spin_lock(&tree->lock);
1795 1796 1797 1798 1799 1800 1801 1802
	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.
	 */
1803
	node = tree_search(tree, cur_start);
C
Chris Mason 已提交
1804
	if (!node)
1805 1806
		goto out;

C
Chris Mason 已提交
1807
	while (1) {
1808 1809 1810
		state = rb_entry(node, struct extent_state, rb_node);
		if (state->start > search_end)
			break;
1811 1812 1813
		if (contig && found && state->start > last + 1)
			break;
		if (state->end >= cur_start && (state->state & bits) == bits) {
1814 1815 1816 1817 1818
			total_bytes += min(search_end, state->end) + 1 -
				       max(cur_start, state->start);
			if (total_bytes >= max_bytes)
				break;
			if (!found) {
1819
				*start = max(cur_start, state->start);
1820 1821
				found = 1;
			}
1822 1823 1824
			last = state->end;
		} else if (contig && found) {
			break;
1825 1826 1827 1828 1829 1830
		}
		node = rb_next(node);
		if (!node)
			break;
	}
out:
1831
	spin_unlock(&tree->lock);
1832 1833
	return total_bytes;
}
1834

C
Chris Mason 已提交
1835 1836 1837 1838
/*
 * set the private field for a given byte offset in the tree.  If there isn't
 * an extent_state there already, this does nothing.
 */
1839
static int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
1840 1841 1842 1843 1844
{
	struct rb_node *node;
	struct extent_state *state;
	int ret = 0;

1845
	spin_lock(&tree->lock);
1846 1847 1848 1849
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1850
	node = tree_search(tree, start);
1851
	if (!node) {
1852 1853 1854 1855 1856 1857 1858 1859 1860 1861
		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:
1862
	spin_unlock(&tree->lock);
1863 1864 1865 1866 1867 1868 1869 1870 1871
	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;

1872
	spin_lock(&tree->lock);
1873 1874 1875 1876
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1877
	node = tree_search(tree, start);
1878
	if (!node) {
1879 1880 1881 1882 1883 1884 1885 1886 1887 1888
		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:
1889
	spin_unlock(&tree->lock);
1890 1891 1892 1893 1894
	return ret;
}

/*
 * searches a range in the state tree for a given mask.
1895
 * If 'filled' == 1, this returns 1 only if every extent in the tree
1896 1897 1898 1899
 * 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,
1900
		   unsigned long bits, int filled, struct extent_state *cached)
1901 1902 1903 1904 1905
{
	struct extent_state *state = NULL;
	struct rb_node *node;
	int bitset = 0;

1906
	spin_lock(&tree->lock);
1907 1908
	if (cached && cached->tree && cached->start <= start &&
	    cached->end > start)
1909 1910 1911
		node = &cached->rb_node;
	else
		node = tree_search(tree, start);
1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930
	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;
		}
1931 1932 1933 1934

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

1935 1936 1937 1938 1939 1940 1941 1942 1943 1944
		start = state->end + 1;
		if (start > end)
			break;
		node = rb_next(node);
		if (!node) {
			if (filled)
				bitset = 0;
			break;
		}
	}
1945
	spin_unlock(&tree->lock);
1946 1947 1948 1949 1950 1951 1952
	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
 */
1953
static void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
1954
{
M
Miao Xie 已提交
1955
	u64 start = page_offset(page);
1956
	u64 end = start + PAGE_CACHE_SIZE - 1;
1957
	if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1958 1959 1960
		SetPageUptodate(page);
}

1961 1962 1963 1964 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
/*
 * 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
1994 1995 1996 1997 1998
	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;
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

	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.
2009
 * to avoid any synchronization issues, wait for the data after writing, which
2010 2011 2012 2013
 * 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.
 */
2014
int repair_io_failure(struct btrfs_fs_info *fs_info, u64 start,
2015 2016 2017 2018 2019 2020 2021 2022
			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
2023
	struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
2024 2025
	int ret;

2026
	ASSERT(!(fs_info->sb->s_flags & MS_RDONLY));
2027 2028
	BUG_ON(!mirror_num);

D
David Woodhouse 已提交
2029 2030 2031 2032
	/* we can't repair anything in raid56 yet */
	if (btrfs_is_parity_mirror(map_tree, logical, length, mirror_num))
		return 0;

2033
	bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2034 2035
	if (!bio)
		return -EIO;
2036
	bio->bi_iter.bi_size = 0;
2037 2038
	map_length = length;

2039
	ret = btrfs_map_block(fs_info, WRITE, logical,
2040 2041 2042 2043 2044 2045 2046
			      &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;
2047
	bio->bi_iter.bi_sector = sector;
2048 2049 2050 2051 2052 2053 2054
	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
2055
	bio_add_page(bio, page, length, start - page_offset(page));
2056

2057
	if (btrfsic_submit_bio_wait(WRITE_SYNC, bio)) {
2058 2059
		/* try to remap that extent elsewhere? */
		bio_put(bio);
2060
		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
2061 2062 2063
		return -EIO;
	}

2064 2065 2066 2067
	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);
2068 2069 2070 2071 2072

	bio_put(bio);
	return 0;
}

2073 2074 2075 2076 2077
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);
2078
	int ret = 0;
2079

2080 2081 2082
	if (root->fs_info->sb->s_flags & MS_RDONLY)
		return -EROFS;

2083 2084
	for (i = 0; i < num_pages; i++) {
		struct page *p = extent_buffer_page(eb, i);
2085
		ret = repair_io_failure(root->fs_info, start, PAGE_CACHE_SIZE,
2086 2087 2088 2089 2090 2091 2092 2093 2094
					start, p, mirror_num);
		if (ret)
			break;
		start += PAGE_CACHE_SIZE;
	}

	return ret;
}

2095 2096 2097 2098 2099 2100 2101 2102 2103
/*
 * 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;
2104 2105
	struct inode *inode = page->mapping->host;
	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131
	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;
	}
2132 2133
	if (fs_info->sb->s_flags & MS_RDONLY)
		goto out;
2134 2135 2136 2137 2138 2139 2140

	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);

2141 2142
	if (state && state->start <= failrec->start &&
	    state->end >= failrec->start + failrec->len - 1) {
2143 2144
		num_copies = btrfs_num_copies(fs_info, failrec->logical,
					      failrec->len);
2145
		if (num_copies > 1)  {
2146
			ret = repair_io_failure(fs_info, start, failrec->len,
2147 2148 2149 2150
						failrec->logical, page,
						failrec->failed_mirror);
			did_repair = !ret;
		}
D
David Woodhouse 已提交
2151
		ret = 0;
2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168
	}

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
 */

2169 2170 2171
static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
			      struct page *page, u64 start, u64 end,
			      int failed_mirror)
2172 2173 2174 2175 2176 2177 2178 2179 2180
{
	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;
2181 2182
	struct btrfs_io_bio *btrfs_failed_bio;
	struct btrfs_io_bio *btrfs_bio;
2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208
	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;
		}

2209
		if (em->start > start || em->start + em->len <= start) {
2210 2211 2212 2213 2214
			free_extent_map(em);
			em = NULL;
		}
		read_unlock(&em_tree->lock);

2215
		if (!em) {
2216 2217 2218 2219 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
			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.
		 */
	}
2258 2259
	num_copies = btrfs_num_copies(BTRFS_I(inode)->root->fs_info,
				      failrec->logical, failrec->len);
2260 2261 2262 2263 2264 2265
	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.
		 */
2266 2267
		pr_debug("bio_readpage_error: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d\n",
			 num_copies, failrec->this_mirror, failed_mirror);
2268 2269 2270 2271 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
		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;
	}

2308 2309
	if (failrec->this_mirror > num_copies) {
		pr_debug("bio_readpage_error: (fail) num_copies=%d, next_mirror %d, failed_mirror %d\n",
2310 2311 2312 2313 2314
			 num_copies, failrec->this_mirror, failed_mirror);
		free_io_failure(inode, failrec, 0);
		return -EIO;
	}

2315
	bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
2316 2317 2318 2319
	if (!bio) {
		free_io_failure(inode, failrec, 0);
		return -EIO;
	}
2320
	bio->bi_end_io = failed_bio->bi_end_io;
2321
	bio->bi_iter.bi_sector = failrec->logical >> 9;
2322
	bio->bi_bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
2323
	bio->bi_iter.bi_size = 0;
2324

2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337
	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);
	}

2338 2339 2340 2341 2342 2343
	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);

2344 2345 2346 2347
	ret = tree->ops->submit_bio_hook(inode, read_mode, bio,
					 failrec->this_mirror,
					 failrec->bio_flags, 0);
	return ret;
2348 2349
}

2350 2351
/* lots and lots of room for performance fixes in the end_bio funcs */

2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369
int end_extent_writepage(struct page *page, int err, u64 start, u64 end)
{
	int uptodate = (err == 0);
	struct extent_io_tree *tree;
	int ret;

	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);
2370 2371
		ret = ret < 0 ? ret : -EIO;
		mapping_set_error(page->mapping, ret);
2372 2373 2374 2375
	}
	return 0;
}

2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386
/*
 * 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)
{
2387
	struct bio_vec *bvec;
2388 2389
	u64 start;
	u64 end;
2390
	int i;
2391

2392
	bio_for_each_segment_all(bvec, bio, i) {
2393
		struct page *page = bvec->bv_page;
2394

2395 2396 2397 2398 2399
		/* 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.  */
2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410
		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);
		}
2411

2412 2413
		start = page_offset(page);
		end = start + bvec->bv_offset + bvec->bv_len - 1;
2414

2415 2416
		if (end_extent_writepage(page, err, start, end))
			continue;
2417

2418
		end_page_writeback(page);
2419
	}
2420

2421 2422 2423
	bio_put(bio);
}

2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435
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);
}

2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448
/*
 * 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)
{
2449
	struct bio_vec *bvec;
2450
	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
2451
	struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
2452
	struct extent_io_tree *tree;
2453
	u64 offset = 0;
2454 2455
	u64 start;
	u64 end;
2456
	u64 len;
2457 2458
	u64 extent_start = 0;
	u64 extent_len = 0;
2459
	int mirror;
2460
	int ret;
2461
	int i;
2462

2463 2464 2465
	if (err)
		uptodate = 0;

2466
	bio_for_each_segment_all(bvec, bio, i) {
2467
		struct page *page = bvec->bv_page;
2468
		struct inode *inode = page->mapping->host;
2469

2470
		pr_debug("end_bio_extent_readpage: bi_sector=%llu, err=%d, "
2471
			 "mirror=%lu\n", (u64)bio->bi_iter.bi_sector, err,
2472
			 io_bio->mirror_num);
2473
		tree = &BTRFS_I(inode)->io_tree;
2474

2475 2476 2477 2478 2479
		/* 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.  */
2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490
		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);
		}
2491

2492 2493
		start = page_offset(page);
		end = start + bvec->bv_offset + bvec->bv_len - 1;
2494
		len = bvec->bv_len;
2495

2496
		mirror = io_bio->mirror_num;
2497 2498
		if (likely(uptodate && tree->ops &&
			   tree->ops->readpage_end_io_hook)) {
2499 2500 2501
			ret = tree->ops->readpage_end_io_hook(io_bio, offset,
							      page, start, end,
							      mirror);
2502
			if (ret)
2503
				uptodate = 0;
2504
			else
2505
				clean_io_failure(start, page);
2506
		}
2507

2508 2509 2510 2511
		if (likely(uptodate))
			goto readpage_ok;

		if (tree->ops && tree->ops->readpage_io_failed_hook) {
2512
			ret = tree->ops->readpage_io_failed_hook(page, mirror);
2513 2514 2515
			if (!ret && !err &&
			    test_bit(BIO_UPTODATE, &bio->bi_flags))
				uptodate = 1;
2516
		} else {
2517 2518 2519 2520 2521 2522 2523 2524 2525 2526
			/*
			 * 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.
			 */
2527 2528
			ret = bio_readpage_error(bio, offset, page, start, end,
						 mirror);
2529
			if (ret == 0) {
2530 2531
				uptodate =
					test_bit(BIO_UPTODATE, &bio->bi_flags);
2532 2533
				if (err)
					uptodate = 0;
2534 2535 2536
				continue;
			}
		}
2537
readpage_ok:
2538
		if (likely(uptodate)) {
2539 2540 2541 2542 2543 2544 2545 2546
			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);
2547
			SetPageUptodate(page);
2548
		} else {
2549 2550
			ClearPageUptodate(page);
			SetPageError(page);
2551
		}
2552
		unlock_page(page);
2553
		offset += len;
2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575

		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;
		}
2576
	}
2577

2578 2579 2580
	if (extent_len)
		endio_readpage_release_extent(tree, extent_start, extent_len,
					      uptodate);
2581 2582
	if (io_bio->end_io)
		io_bio->end_io(io_bio, err);
2583 2584 2585
	bio_put(bio);
}

2586 2587 2588 2589
/*
 * 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
 */
2590 2591 2592
struct bio *
btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
		gfp_t gfp_flags)
2593
{
2594
	struct btrfs_io_bio *btrfs_bio;
2595 2596
	struct bio *bio;

2597
	bio = bio_alloc_bioset(gfp_flags, nr_vecs, btrfs_bioset);
2598 2599

	if (bio == NULL && (current->flags & PF_MEMALLOC)) {
2600 2601 2602 2603
		while (!bio && (nr_vecs /= 2)) {
			bio = bio_alloc_bioset(gfp_flags,
					       nr_vecs, btrfs_bioset);
		}
2604 2605 2606 2607
	}

	if (bio) {
		bio->bi_bdev = bdev;
2608
		bio->bi_iter.bi_sector = first_sector;
2609 2610 2611 2612
		btrfs_bio = btrfs_io_bio(bio);
		btrfs_bio->csum = NULL;
		btrfs_bio->csum_allocated = NULL;
		btrfs_bio->end_io = NULL;
2613 2614 2615 2616
	}
	return bio;
}

2617 2618 2619 2620 2621 2622 2623 2624 2625
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)
{
2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636
	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;
2637 2638 2639
}


2640 2641
static int __must_check submit_one_bio(int rw, struct bio *bio,
				       int mirror_num, unsigned long bio_flags)
2642 2643
{
	int ret = 0;
2644 2645 2646 2647 2648
	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
2649
	start = page_offset(page) + bvec->bv_offset;
2650

2651
	bio->bi_private = NULL;
2652 2653 2654

	bio_get(bio);

2655
	if (tree->ops && tree->ops->submit_bio_hook)
2656
		ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
2657
					   mirror_num, bio_flags, start);
2658
	else
2659
		btrfsic_submit_bio(rw, bio);
2660

2661 2662 2663 2664 2665 2666
	if (bio_flagged(bio, BIO_EOPNOTSUPP))
		ret = -EOPNOTSUPP;
	bio_put(bio);
	return ret;
}

2667
static int merge_bio(int rw, struct extent_io_tree *tree, struct page *page,
2668 2669 2670 2671 2672
		     unsigned long offset, size_t size, struct bio *bio,
		     unsigned long bio_flags)
{
	int ret = 0;
	if (tree->ops && tree->ops->merge_bio_hook)
2673
		ret = tree->ops->merge_bio_hook(rw, page, offset, size, bio,
2674 2675 2676 2677 2678 2679
						bio_flags);
	BUG_ON(ret < 0);
	return ret;

}

2680 2681 2682 2683 2684 2685
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,
2686
			      bio_end_io_t end_io_func,
C
Chris Mason 已提交
2687 2688 2689
			      int mirror_num,
			      unsigned long prev_bio_flags,
			      unsigned long bio_flags)
2690 2691 2692 2693
{
	int ret = 0;
	struct bio *bio;
	int nr;
C
Chris Mason 已提交
2694 2695 2696
	int contig = 0;
	int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
	int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
2697
	size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
2698 2699 2700

	if (bio_ret && *bio_ret) {
		bio = *bio_ret;
C
Chris Mason 已提交
2701
		if (old_compressed)
2702
			contig = bio->bi_iter.bi_sector == sector;
C
Chris Mason 已提交
2703
		else
K
Kent Overstreet 已提交
2704
			contig = bio_end_sector(bio) == sector;
C
Chris Mason 已提交
2705 2706

		if (prev_bio_flags != bio_flags || !contig ||
2707
		    merge_bio(rw, tree, page, offset, page_size, bio, bio_flags) ||
C
Chris Mason 已提交
2708 2709 2710
		    bio_add_page(bio, page, page_size, offset) < page_size) {
			ret = submit_one_bio(rw, bio, mirror_num,
					     prev_bio_flags);
2711 2712
			if (ret < 0)
				return ret;
2713 2714 2715 2716 2717
			bio = NULL;
		} else {
			return 0;
		}
	}
C
Chris Mason 已提交
2718 2719 2720 2721 2722
	if (this_compressed)
		nr = BIO_MAX_PAGES;
	else
		nr = bio_get_nr_vecs(bdev);

2723
	bio = btrfs_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
2724 2725
	if (!bio)
		return -ENOMEM;
2726

C
Chris Mason 已提交
2727
	bio_add_page(bio, page, page_size, offset);
2728 2729
	bio->bi_end_io = end_io_func;
	bio->bi_private = tree;
2730

C
Chris Mason 已提交
2731
	if (bio_ret)
2732
		*bio_ret = bio;
C
Chris Mason 已提交
2733
	else
C
Chris Mason 已提交
2734
		ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
2735 2736 2737 2738

	return ret;
}

2739 2740
static void attach_extent_buffer_page(struct extent_buffer *eb,
				      struct page *page)
2741 2742 2743 2744
{
	if (!PagePrivate(page)) {
		SetPagePrivate(page);
		page_cache_get(page);
J
Josef Bacik 已提交
2745 2746 2747
		set_page_private(page, (unsigned long)eb);
	} else {
		WARN_ON(page->private != (unsigned long)eb);
2748 2749 2750
	}
}

J
Josef Bacik 已提交
2751
void set_page_extent_mapped(struct page *page)
2752
{
J
Josef Bacik 已提交
2753 2754 2755 2756 2757
	if (!PagePrivate(page)) {
		SetPagePrivate(page);
		page_cache_get(page);
		set_page_private(page, EXTENT_PAGE_PRIVATE);
	}
2758 2759
}

2760 2761 2762 2763 2764 2765 2766 2767 2768
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;
2769
		if (extent_map_in_tree(em) && start >= em->start &&
2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786
		    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;
}
2787 2788 2789 2790
/*
 * 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)
2791
 * XXX JDM: This needs looking at to ensure proper page locking
2792
 */
2793 2794 2795
static int __do_readpage(struct extent_io_tree *tree,
			 struct page *page,
			 get_extent_t *get_extent,
2796
			 struct extent_map **em_cached,
2797 2798
			 struct bio **bio, int mirror_num,
			 unsigned long *bio_flags, int rw)
2799 2800
{
	struct inode *inode = page->mapping->host;
M
Miao Xie 已提交
2801
	u64 start = page_offset(page);
2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813
	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;
2814
	int parent_locked = *bio_flags & EXTENT_BIO_PARENT_LOCKED;
2815
	size_t pg_offset = 0;
2816
	size_t iosize;
C
Chris Mason 已提交
2817
	size_t disk_io_size;
2818
	size_t blocksize = inode->i_sb->s_blocksize;
2819
	unsigned long this_bio_flag = *bio_flags & EXTENT_BIO_PARENT_LOCKED;
2820 2821 2822

	set_page_extent_mapped(page);

2823
	end = page_end;
D
Dan Magenheimer 已提交
2824 2825 2826
	if (!PageUptodate(page)) {
		if (cleancache_get_page(page) == 0) {
			BUG_ON(blocksize != PAGE_SIZE);
2827
			unlock_extent(tree, start, end);
D
Dan Magenheimer 已提交
2828 2829 2830 2831
			goto out;
		}
	}

C
Chris Mason 已提交
2832 2833 2834 2835 2836 2837
	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;
2838
			userpage = kmap_atomic(page);
C
Chris Mason 已提交
2839 2840
			memset(userpage + zero_offset, 0, iosize);
			flush_dcache_page(page);
2841
			kunmap_atomic(userpage);
C
Chris Mason 已提交
2842 2843
		}
	}
2844
	while (cur <= end) {
2845 2846
		unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;

2847 2848
		if (cur >= last_byte) {
			char *userpage;
2849 2850
			struct extent_state *cached = NULL;

2851
			iosize = PAGE_CACHE_SIZE - pg_offset;
2852
			userpage = kmap_atomic(page);
2853
			memset(userpage + pg_offset, 0, iosize);
2854
			flush_dcache_page(page);
2855
			kunmap_atomic(userpage);
2856
			set_extent_uptodate(tree, cur, cur + iosize - 1,
2857
					    &cached, GFP_NOFS);
2858 2859 2860 2861
			if (!parent_locked)
				unlock_extent_cached(tree, cur,
						     cur + iosize - 1,
						     &cached, GFP_NOFS);
2862 2863
			break;
		}
2864 2865
		em = __get_extent_map(inode, page, pg_offset, cur,
				      end - cur + 1, get_extent, em_cached);
2866
		if (IS_ERR_OR_NULL(em)) {
2867
			SetPageError(page);
2868 2869
			if (!parent_locked)
				unlock_extent(tree, cur, end);
2870 2871 2872 2873 2874 2875
			break;
		}
		extent_offset = cur - em->start;
		BUG_ON(extent_map_end(em) <= cur);
		BUG_ON(end < cur);

2876
		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
2877
			this_bio_flag |= EXTENT_BIO_COMPRESSED;
2878 2879 2880
			extent_set_compress_type(&this_bio_flag,
						 em->compress_type);
		}
C
Chris Mason 已提交
2881

2882 2883
		iosize = min(extent_map_end(em) - cur, end - cur + 1);
		cur_end = min(extent_map_end(em) - 1, end);
2884
		iosize = ALIGN(iosize, blocksize);
C
Chris Mason 已提交
2885 2886 2887 2888 2889 2890 2891
		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;
		}
2892 2893
		bdev = em->bdev;
		block_start = em->block_start;
Y
Yan Zheng 已提交
2894 2895
		if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
			block_start = EXTENT_MAP_HOLE;
2896 2897 2898 2899 2900 2901
		free_extent_map(em);
		em = NULL;

		/* we've found a hole, just zero and go on */
		if (block_start == EXTENT_MAP_HOLE) {
			char *userpage;
2902 2903
			struct extent_state *cached = NULL;

2904
			userpage = kmap_atomic(page);
2905
			memset(userpage + pg_offset, 0, iosize);
2906
			flush_dcache_page(page);
2907
			kunmap_atomic(userpage);
2908 2909

			set_extent_uptodate(tree, cur, cur + iosize - 1,
2910 2911 2912
					    &cached, GFP_NOFS);
			unlock_extent_cached(tree, cur, cur + iosize - 1,
			                     &cached, GFP_NOFS);
2913
			cur = cur + iosize;
2914
			pg_offset += iosize;
2915 2916 2917
			continue;
		}
		/* the get_extent function already copied into the page */
2918 2919
		if (test_range_bit(tree, cur, cur_end,
				   EXTENT_UPTODATE, 1, NULL)) {
2920
			check_page_uptodate(tree, page);
2921 2922
			if (!parent_locked)
				unlock_extent(tree, cur, cur + iosize - 1);
2923
			cur = cur + iosize;
2924
			pg_offset += iosize;
2925 2926
			continue;
		}
2927 2928 2929 2930 2931
		/* we have an inline extent but it didn't get marked up
		 * to date.  Error out
		 */
		if (block_start == EXTENT_MAP_INLINE) {
			SetPageError(page);
2932 2933
			if (!parent_locked)
				unlock_extent(tree, cur, cur + iosize - 1);
2934
			cur = cur + iosize;
2935
			pg_offset += iosize;
2936 2937
			continue;
		}
2938

2939
		pnr -= page->index;
2940
		ret = submit_extent_page(rw, tree, page,
2941
					 sector, disk_io_size, pg_offset,
2942
					 bdev, bio, pnr,
C
Chris Mason 已提交
2943 2944 2945
					 end_bio_extent_readpage, mirror_num,
					 *bio_flags,
					 this_bio_flag);
2946 2947 2948 2949
		if (!ret) {
			nr++;
			*bio_flags = this_bio_flag;
		} else {
2950
			SetPageError(page);
2951 2952
			if (!parent_locked)
				unlock_extent(tree, cur, cur + iosize - 1);
2953
		}
2954
		cur = cur + iosize;
2955
		pg_offset += iosize;
2956
	}
D
Dan Magenheimer 已提交
2957
out:
2958 2959 2960 2961 2962 2963 2964 2965
	if (!nr) {
		if (!PageError(page))
			SetPageUptodate(page);
		unlock_page(page);
	}
	return 0;
}

2966 2967 2968 2969
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,
2970
					     struct extent_map **em_cached,
2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990
					     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++) {
2991 2992
		__do_readpage(tree, pages[index], get_extent, em_cached, bio,
			      mirror_num, bio_flags, rw);
2993 2994 2995 2996 2997 2998 2999
		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,
3000
			       struct extent_map **em_cached,
3001 3002 3003
			       struct bio **bio, int mirror_num,
			       unsigned long *bio_flags, int rw)
{
3004
	u64 start = 0;
3005 3006 3007
	u64 end = 0;
	u64 page_start;
	int index;
3008
	int first_index = 0;
3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020

	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,
3021 3022 3023
						  end, get_extent, em_cached,
						  bio, mirror_num, bio_flags,
						  rw);
3024 3025 3026 3027 3028 3029 3030 3031 3032
			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,
3033
					  end, get_extent, em_cached, bio,
3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058
					  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);
	}

3059 3060
	ret = __do_readpage(tree, page, get_extent, NULL, bio, mirror_num,
			    bio_flags, rw);
3061 3062 3063
	return ret;
}

3064
int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
3065
			    get_extent_t *get_extent, int mirror_num)
3066 3067
{
	struct bio *bio = NULL;
C
Chris Mason 已提交
3068
	unsigned long bio_flags = 0;
3069 3070
	int ret;

3071
	ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
3072
				      &bio_flags, READ);
3073
	if (bio)
3074
		ret = submit_one_bio(READ, bio, mirror_num, bio_flags);
3075 3076 3077
	return ret;
}

3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091
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;
}

3092 3093 3094 3095 3096 3097 3098 3099 3100 3101
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;
}

3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113
/*
 * 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;
	struct extent_io_tree *tree = epd->tree;
M
Miao Xie 已提交
3114
	u64 start = page_offset(page);
3115 3116 3117 3118 3119 3120 3121 3122 3123
	u64 delalloc_start;
	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 iosize;
	sector_t sector;
3124
	struct extent_state *cached_state = NULL;
3125 3126 3127 3128
	struct extent_map *em;
	struct block_device *bdev;
	int ret;
	int nr = 0;
3129
	size_t pg_offset = 0;
3130 3131 3132 3133 3134
	size_t blocksize;
	loff_t i_size = i_size_read(inode);
	unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
	u64 nr_delalloc;
	u64 delalloc_end;
C
Chris Mason 已提交
3135 3136
	int page_started;
	int compressed;
3137
	int write_flags;
3138
	unsigned long nr_written = 0;
3139
	bool fill_delalloc = true;
3140

3141
	if (wbc->sync_mode == WB_SYNC_ALL)
J
Jens Axboe 已提交
3142
		write_flags = WRITE_SYNC;
3143 3144 3145
	else
		write_flags = WRITE;

3146 3147
	trace___extent_writepage(page, inode, wbc);

3148
	WARN_ON(!PageLocked(page));
3149 3150 3151

	ClearPageError(page);

3152
	pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
3153
	if (page->index > end_index ||
3154
	   (page->index == end_index && !pg_offset)) {
3155
		page->mapping->a_ops->invalidatepage(page, 0, PAGE_CACHE_SIZE);
3156 3157 3158 3159 3160 3161 3162
		unlock_page(page);
		return 0;
	}

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

3163
		userpage = kmap_atomic(page);
3164 3165
		memset(userpage + pg_offset, 0,
		       PAGE_CACHE_SIZE - pg_offset);
3166
		kunmap_atomic(userpage);
3167
		flush_dcache_page(page);
3168
	}
3169
	pg_offset = 0;
3170 3171 3172

	set_page_extent_mapped(page);

3173 3174 3175
	if (!tree->ops || !tree->ops->fill_delalloc)
		fill_delalloc = false;

3176 3177
	delalloc_start = start;
	delalloc_end = 0;
C
Chris Mason 已提交
3178
	page_started = 0;
3179
	if (!epd->extent_locked && fill_delalloc) {
3180
		u64 delalloc_to_write = 0;
3181 3182 3183 3184 3185 3186
		/*
		 * make sure the wbc mapping index is at least updated
		 * to this page.
		 */
		update_nr_written(page, wbc, 0);

C
Chris Mason 已提交
3187
		while (delalloc_end < page_end) {
3188
			nr_delalloc = find_lock_delalloc_range(inode, tree,
C
Chris Mason 已提交
3189 3190
						       page,
						       &delalloc_start,
3191 3192
						       &delalloc_end,
						       128 * 1024 * 1024);
3193 3194 3195 3196
			if (nr_delalloc == 0) {
				delalloc_start = delalloc_end + 1;
				continue;
			}
3197 3198 3199 3200 3201
			ret = tree->ops->fill_delalloc(inode, page,
						       delalloc_start,
						       delalloc_end,
						       &page_started,
						       &nr_written);
3202 3203 3204 3205 3206
			/* File system has been set read-only */
			if (ret) {
				SetPageError(page);
				goto done;
			}
3207 3208 3209 3210 3211 3212 3213 3214
			/*
			 * 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;
3215 3216
			delalloc_start = delalloc_end + 1;
		}
3217 3218 3219 3220 3221 3222 3223 3224
		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);
		}
C
Chris Mason 已提交
3225

3226 3227 3228 3229 3230
		/* did the fill delalloc function already unlock and start
		 * the IO?
		 */
		if (page_started) {
			ret = 0;
3231 3232 3233 3234 3235 3236 3237
			/*
			 * 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;
			goto done_unlocked;
3238
		}
C
Chris Mason 已提交
3239
	}
3240
	if (tree->ops && tree->ops->writepage_start_hook) {
C
Chris Mason 已提交
3241 3242
		ret = tree->ops->writepage_start_hook(page, start,
						      page_end);
3243 3244 3245 3246 3247 3248
		if (ret) {
			/* Fixup worker will requeue */
			if (ret == -EBUSY)
				wbc->pages_skipped++;
			else
				redirty_page_for_writepage(wbc, page);
3249
			update_nr_written(page, wbc, nr_written);
3250
			unlock_page(page);
3251
			ret = 0;
3252
			goto done_unlocked;
3253 3254 3255
		}
	}

3256 3257 3258 3259 3260
	/*
	 * 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);
3261

3262 3263
	end = page_end;
	if (last_byte <= start) {
3264 3265 3266
		if (tree->ops && tree->ops->writepage_end_io_hook)
			tree->ops->writepage_end_io_hook(page, start,
							 page_end, NULL, 1);
3267 3268 3269 3270 3271 3272 3273
		goto done;
	}

	blocksize = inode->i_sb->s_blocksize;

	while (cur <= end) {
		if (cur >= last_byte) {
3274 3275 3276
			if (tree->ops && tree->ops->writepage_end_io_hook)
				tree->ops->writepage_end_io_hook(page, cur,
							 page_end, NULL, 1);
3277 3278
			break;
		}
3279
		em = epd->get_extent(inode, page, pg_offset, cur,
3280
				     end - cur + 1, 1);
3281
		if (IS_ERR_OR_NULL(em)) {
3282
			SetPageError(page);
3283
			ret = PTR_ERR_OR_ZERO(em);
3284 3285 3286 3287 3288 3289 3290
			break;
		}

		extent_offset = cur - em->start;
		BUG_ON(extent_map_end(em) <= cur);
		BUG_ON(end < cur);
		iosize = min(extent_map_end(em) - cur, end - cur + 1);
3291
		iosize = ALIGN(iosize, blocksize);
3292 3293 3294
		sector = (em->block_start + extent_offset) >> 9;
		bdev = em->bdev;
		block_start = em->block_start;
C
Chris Mason 已提交
3295
		compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
3296 3297 3298
		free_extent_map(em);
		em = NULL;

C
Chris Mason 已提交
3299 3300 3301 3302 3303
		/*
		 * compressed and inline extents are written through other
		 * paths in the FS
		 */
		if (compressed || block_start == EXTENT_MAP_HOLE ||
3304
		    block_start == EXTENT_MAP_INLINE) {
C
Chris Mason 已提交
3305 3306 3307 3308 3309 3310
			/*
			 * end_io notification does not happen here for
			 * compressed extents
			 */
			if (!compressed && tree->ops &&
			    tree->ops->writepage_end_io_hook)
3311 3312 3313
				tree->ops->writepage_end_io_hook(page, cur,
							 cur + iosize - 1,
							 NULL, 1);
C
Chris Mason 已提交
3314 3315 3316 3317 3318 3319 3320 3321 3322
			else if (compressed) {
				/* we don't want to end_page_writeback on
				 * a compressed extent.  this happens
				 * elsewhere
				 */
				nr++;
			}

			cur += iosize;
3323
			pg_offset += iosize;
3324 3325 3326 3327
			continue;
		}
		/* leave this out until we have a page_mkwrite call */
		if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
3328
				   EXTENT_DIRTY, 0, NULL)) {
3329
			cur = cur + iosize;
3330
			pg_offset += iosize;
3331 3332
			continue;
		}
C
Chris Mason 已提交
3333

3334 3335 3336 3337 3338 3339
		if (tree->ops && tree->ops->writepage_io_hook) {
			ret = tree->ops->writepage_io_hook(page, cur,
						cur + iosize - 1);
		} else {
			ret = 0;
		}
3340
		if (ret) {
3341
			SetPageError(page);
3342
		} else {
3343
			unsigned long max_nr = end_index + 1;
3344

3345 3346
			set_range_writeback(tree, cur, cur + iosize - 1);
			if (!PageWriteback(page)) {
3347 3348
				btrfs_err(BTRFS_I(inode)->root->fs_info,
					   "page %lu not writeback, cur %llu end %llu",
3349
				       page->index, cur, end);
3350 3351
			}

3352 3353 3354
			ret = submit_extent_page(write_flags, tree, page,
						 sector, iosize, pg_offset,
						 bdev, &epd->bio, max_nr,
C
Chris Mason 已提交
3355 3356
						 end_bio_extent_writepage,
						 0, 0, 0);
3357 3358 3359 3360
			if (ret)
				SetPageError(page);
		}
		cur = cur + iosize;
3361
		pg_offset += iosize;
3362 3363 3364 3365 3366 3367 3368 3369
		nr++;
	}
done:
	if (nr == 0) {
		/* make sure the mapping tag for page dirty gets cleared */
		set_page_writeback(page);
		end_page_writeback(page);
	}
3370 3371 3372 3373
	if (PageError(page)) {
		ret = ret < 0 ? ret : -EIO;
		end_extent_writepage(page, ret, start, page_end);
	}
3374
	unlock_page(page);
3375

3376 3377
done_unlocked:

3378 3379
	/* drop our reference on any cached states */
	free_extent_state(cached_state);
3380
	return ret;
3381 3382
}

3383 3384 3385 3386 3387 3388
static int eb_wait(void *word)
{
	io_schedule();
	return 0;
}

3389
void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
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
{
	wait_on_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK, eb_wait,
		    TASK_UNINTERRUPTIBLE);
}

static int lock_extent_buffer_for_io(struct extent_buffer *eb,
				     struct btrfs_fs_info *fs_info,
				     struct extent_page_data *epd)
{
	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
3417 3418 3419 3420 3421
		while (1) {
			wait_on_extent_buffer_writeback(eb);
			btrfs_tree_lock(eb);
			if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
				break;
3422 3423 3424 3425
			btrfs_tree_unlock(eb);
		}
	}

3426 3427 3428 3429 3430 3431
	/*
	 * 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);
3432 3433
	if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
		set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
3434
		spin_unlock(&eb->refs_lock);
3435
		btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3436 3437 3438
		__percpu_counter_add(&fs_info->dirty_metadata_bytes,
				     -eb->len,
				     fs_info->dirty_metadata_batch);
3439
		ret = 1;
3440 3441
	} else {
		spin_unlock(&eb->refs_lock);
3442 3443 3444 3445 3446 3447 3448 3449 3450 3451 3452 3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473
	}

	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);
	smp_mb__after_clear_bit();
	wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
}

static void end_bio_extent_buffer_writepage(struct bio *bio, int err)
{
3474
	struct bio_vec *bvec;
3475
	struct extent_buffer *eb;
3476
	int i, done;
3477

3478
	bio_for_each_segment_all(bvec, bio, i) {
3479 3480 3481 3482 3483 3484
		struct page *page = bvec->bv_page;

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

3485
		if (err || test_bit(EXTENT_BUFFER_IOERR, &eb->bflags)) {
3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496
			set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
			ClearPageUptodate(page);
			SetPageError(page);
		}

		end_page_writeback(page);

		if (!done)
			continue;

		end_extent_buffer_writeback(eb);
3497
	}
3498 3499 3500 3501 3502 3503 3504 3505 3506 3507

	bio_put(bio);
}

static int write_one_eb(struct extent_buffer *eb,
			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;
3508
	struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
3509 3510
	u64 offset = eb->start;
	unsigned long i, num_pages;
3511
	unsigned long bio_flags = 0;
3512
	int rw = (epd->sync_io ? WRITE_SYNC : WRITE) | REQ_META;
3513
	int ret = 0;
3514 3515 3516 3517

	clear_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
	num_pages = num_extent_pages(eb->start, eb->len);
	atomic_set(&eb->io_pages, num_pages);
3518 3519 3520
	if (btrfs_header_owner(eb) == BTRFS_TREE_LOG_OBJECTID)
		bio_flags = EXTENT_BIO_TREE_LOG;

3521 3522 3523 3524 3525
	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);
3526
		ret = submit_extent_page(rw, tree, p, offset >> 9,
3527 3528
					 PAGE_CACHE_SIZE, 0, bdev, &epd->bio,
					 -1, end_bio_extent_buffer_writepage,
3529 3530
					 0, epd->bio_flags, bio_flags);
		epd->bio_flags = bio_flags;
3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564
		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,
3565
		.bio_flags = 0,
3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579 3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590 3591 3592 3593 3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609
	};
	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;
			}

3610 3611 3612 3613 3614 3615
			spin_lock(&mapping->private_lock);
			if (!PagePrivate(page)) {
				spin_unlock(&mapping->private_lock);
				continue;
			}

3616
			eb = (struct extent_buffer *)page->private;
3617 3618 3619 3620 3621 3622

			/*
			 * 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.
			 */
3623
			if (WARN_ON(!eb)) {
3624
				spin_unlock(&mapping->private_lock);
3625 3626 3627
				continue;
			}

3628 3629
			if (eb == prev_eb) {
				spin_unlock(&mapping->private_lock);
3630
				continue;
3631
			}
3632

3633 3634 3635
			ret = atomic_inc_not_zero(&eb->refs);
			spin_unlock(&mapping->private_lock);
			if (!ret)
3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651 3652 3653 3654 3655 3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675
				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;
}

3676
/**
C
Chris Mason 已提交
3677
 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690
 * @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.
 */
3691
static int extent_write_cache_pages(struct extent_io_tree *tree,
C
Chris Mason 已提交
3692 3693
			     struct address_space *mapping,
			     struct writeback_control *wbc,
C
Chris Mason 已提交
3694 3695
			     writepage_t writepage, void *data,
			     void (*flush_fn)(void *))
3696
{
3697
	struct inode *inode = mapping->host;
3698 3699
	int ret = 0;
	int done = 0;
3700
	int err = 0;
3701
	int nr_to_write_done = 0;
3702 3703 3704 3705 3706
	struct pagevec pvec;
	int nr_pages;
	pgoff_t index;
	pgoff_t end;		/* Inclusive */
	int scanned = 0;
3707
	int tag;
3708

3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720
	/*
	 * 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;

3721 3722 3723 3724 3725 3726 3727 3728 3729
	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;
	}
3730 3731 3732 3733
	if (wbc->sync_mode == WB_SYNC_ALL)
		tag = PAGECACHE_TAG_TOWRITE;
	else
		tag = PAGECACHE_TAG_DIRTY;
3734
retry:
3735 3736
	if (wbc->sync_mode == WB_SYNC_ALL)
		tag_pages_for_writeback(mapping, index, end);
3737
	while (!done && !nr_to_write_done && (index <= end) &&
3738 3739
	       (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
			min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
3740 3741 3742 3743 3744 3745 3746 3747 3748 3749 3750 3751 3752
		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
			 */
3753 3754 3755
			if (!trylock_page(page)) {
				flush_fn(data);
				lock_page(page);
3756
			}
3757 3758 3759 3760 3761 3762 3763 3764 3765 3766 3767 3768

			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
3769
			if (wbc->sync_mode != WB_SYNC_NONE) {
3770 3771
				if (PageWriteback(page))
					flush_fn(data);
3772
				wait_on_page_writeback(page);
C
Chris Mason 已提交
3773
			}
3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786

			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;
			}
3787 3788
			if (!err && ret < 0)
				err = ret;
3789 3790 3791 3792 3793 3794 3795

			/*
			 * 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;
3796 3797 3798 3799
		}
		pagevec_release(&pvec);
		cond_resched();
	}
3800
	if (!scanned && !done && !err) {
3801 3802 3803 3804 3805 3806 3807 3808
		/*
		 * 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;
	}
3809
	btrfs_add_delayed_iput(inode);
3810
	return err;
3811 3812
}

3813
static void flush_epd_write_bio(struct extent_page_data *epd)
C
Chris Mason 已提交
3814 3815
{
	if (epd->bio) {
3816 3817 3818
		int rw = WRITE;
		int ret;

3819
		if (epd->sync_io)
3820 3821
			rw = WRITE_SYNC;

3822
		ret = submit_one_bio(rw, epd->bio, 0, epd->bio_flags);
3823
		BUG_ON(ret < 0); /* -ENOMEM */
C
Chris Mason 已提交
3824 3825 3826 3827
		epd->bio = NULL;
	}
}

3828 3829 3830 3831 3832 3833
static noinline void flush_write_bio(void *data)
{
	struct extent_page_data *epd = data;
	flush_epd_write_bio(epd);
}

3834 3835 3836 3837 3838 3839 3840 3841 3842
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,
3843
		.extent_locked = 0,
3844
		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
3845
		.bio_flags = 0,
3846 3847 3848 3849
	};

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

3850
	flush_epd_write_bio(&epd);
3851 3852 3853
	return ret;
}

3854 3855 3856 3857 3858 3859 3860 3861 3862 3863 3864 3865 3866 3867 3868
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,
3869
		.sync_io = mode == WB_SYNC_ALL,
3870
		.bio_flags = 0,
3871 3872 3873 3874 3875 3876 3877 3878
	};
	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
3879
	while (start <= end) {
3880 3881 3882 3883 3884 3885 3886 3887 3888 3889 3890 3891 3892 3893
		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;
	}

3894
	flush_epd_write_bio(&epd);
3895 3896
	return ret;
}
3897 3898 3899 3900 3901 3902 3903 3904 3905 3906 3907

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,
3908
		.extent_locked = 0,
3909
		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
3910
		.bio_flags = 0,
3911 3912
	};

C
Chris Mason 已提交
3913
	ret = extent_write_cache_pages(tree, mapping, wbc,
C
Chris Mason 已提交
3914 3915
				       __extent_writepage, &epd,
				       flush_write_bio);
3916
	flush_epd_write_bio(&epd);
3917 3918 3919 3920 3921 3922 3923 3924 3925 3926
	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
3927
	unsigned long bio_flags = 0;
L
Liu Bo 已提交
3928 3929
	struct page *pagepool[16];
	struct page *page;
3930
	struct extent_map *em_cached = NULL;
L
Liu Bo 已提交
3931
	int nr = 0;
3932 3933

	for (page_idx = 0; page_idx < nr_pages; page_idx++) {
L
Liu Bo 已提交
3934
		page = list_entry(pages->prev, struct page, lru);
3935 3936 3937

		prefetchw(&page->flags);
		list_del(&page->lru);
L
Liu Bo 已提交
3938
		if (add_to_page_cache_lru(page, mapping,
3939
					page->index, GFP_NOFS)) {
L
Liu Bo 已提交
3940 3941
			page_cache_release(page);
			continue;
3942
		}
L
Liu Bo 已提交
3943 3944 3945 3946

		pagepool[nr++] = page;
		if (nr < ARRAY_SIZE(pagepool))
			continue;
3947
		__extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
3948
				   &bio, 0, &bio_flags, READ);
L
Liu Bo 已提交
3949
		nr = 0;
3950
	}
3951
	if (nr)
3952
		__extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
3953
				   &bio, 0, &bio_flags, READ);
L
Liu Bo 已提交
3954

3955 3956 3957
	if (em_cached)
		free_extent_map(em_cached);

3958 3959
	BUG_ON(!list_empty(pages));
	if (bio)
3960
		return submit_one_bio(READ, bio, 0, bio_flags);
3961 3962 3963 3964 3965 3966 3967 3968 3969 3970 3971
	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)
{
3972
	struct extent_state *cached_state = NULL;
M
Miao Xie 已提交
3973
	u64 start = page_offset(page);
3974 3975 3976
	u64 end = start + PAGE_CACHE_SIZE - 1;
	size_t blocksize = page->mapping->host->i_sb->s_blocksize;

3977
	start += ALIGN(offset, blocksize);
3978 3979 3980
	if (start > end)
		return 0;

3981
	lock_extent_bits(tree, start, end, 0, &cached_state);
3982
	wait_on_page_writeback(page);
3983
	clear_extent_bit(tree, start, end,
3984 3985
			 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
			 EXTENT_DO_ACCOUNTING,
3986
			 1, 1, &cached_state, GFP_NOFS);
3987 3988 3989
	return 0;
}

3990 3991 3992 3993 3994
/*
 * 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.
 */
3995 3996 3997
static int try_release_extent_state(struct extent_map_tree *map,
				    struct extent_io_tree *tree,
				    struct page *page, gfp_t mask)
3998
{
M
Miao Xie 已提交
3999
	u64 start = page_offset(page);
4000 4001 4002
	u64 end = start + PAGE_CACHE_SIZE - 1;
	int ret = 1;

4003
	if (test_range_bit(tree, start, end,
4004
			   EXTENT_IOBITS, 0, NULL))
4005 4006 4007 4008
		ret = 0;
	else {
		if ((mask & GFP_NOFS) == GFP_NOFS)
			mask = GFP_NOFS;
4009 4010 4011 4012
		/*
		 * at this point we can safely clear everything except the
		 * locked bit and the nodatasum bit
		 */
4013
		ret = clear_extent_bit(tree, start, end,
4014 4015
				 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
				 0, 0, NULL, mask);
4016 4017 4018 4019 4020 4021 4022 4023

		/* if clear_extent_bit failed for enomem reasons,
		 * we can't allow the release to continue.
		 */
		if (ret < 0)
			ret = 0;
		else
			ret = 1;
4024 4025 4026 4027
	}
	return ret;
}

4028 4029 4030 4031 4032 4033
/*
 * 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,
4034 4035
			       struct extent_io_tree *tree, struct page *page,
			       gfp_t mask)
4036 4037
{
	struct extent_map *em;
M
Miao Xie 已提交
4038
	u64 start = page_offset(page);
4039
	u64 end = start + PAGE_CACHE_SIZE - 1;
4040

4041 4042
	if ((mask & __GFP_WAIT) &&
	    page->mapping->host->i_size > 16 * 1024 * 1024) {
4043
		u64 len;
4044
		while (start <= end) {
4045
			len = end - start + 1;
4046
			write_lock(&map->lock);
4047
			em = lookup_extent_mapping(map, start, len);
4048
			if (!em) {
4049
				write_unlock(&map->lock);
4050 4051
				break;
			}
4052 4053
			if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
			    em->start != start) {
4054
				write_unlock(&map->lock);
4055 4056 4057 4058 4059
				free_extent_map(em);
				break;
			}
			if (!test_range_bit(tree, em->start,
					    extent_map_end(em) - 1,
4060
					    EXTENT_LOCKED | EXTENT_WRITEBACK,
4061
					    0, NULL)) {
4062 4063 4064 4065 4066
				remove_extent_mapping(map, em);
				/* once for the rb tree */
				free_extent_map(em);
			}
			start = extent_map_end(em);
4067
			write_unlock(&map->lock);
4068 4069

			/* once for us */
4070 4071 4072
			free_extent_map(em);
		}
	}
4073
	return try_release_extent_state(map, tree, page, mask);
4074 4075
}

4076 4077 4078 4079 4080 4081 4082 4083 4084 4085 4086 4087 4088 4089 4090 4091
/*
 * 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;

4092
	while (1) {
4093 4094 4095
		len = last - offset;
		if (len == 0)
			break;
4096
		len = ALIGN(len, sectorsize);
4097
		em = get_extent(inode, NULL, 0, offset, len, 0);
4098
		if (IS_ERR_OR_NULL(em))
4099 4100 4101 4102 4103 4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115
			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;
}

4116 4117 4118 4119 4120 4121 4122 4123 4124 4125 4126 4127 4128
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
4129 4130 4131
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
4132
	int ret = 0;
Y
Yehuda Sadeh 已提交
4133 4134 4135
	u64 off = start;
	u64 max = start + len;
	u32 flags = 0;
J
Josef Bacik 已提交
4136 4137
	u32 found_type;
	u64 last;
4138
	u64 last_for_get_extent = 0;
Y
Yehuda Sadeh 已提交
4139
	u64 disko = 0;
4140
	u64 isize = i_size_read(inode);
J
Josef Bacik 已提交
4141
	struct btrfs_key found_key;
Y
Yehuda Sadeh 已提交
4142
	struct extent_map *em = NULL;
4143
	struct extent_state *cached_state = NULL;
J
Josef Bacik 已提交
4144
	struct btrfs_path *path;
Y
Yehuda Sadeh 已提交
4145
	int end = 0;
4146 4147 4148
	u64 em_start = 0;
	u64 em_len = 0;
	u64 em_end = 0;
Y
Yehuda Sadeh 已提交
4149 4150 4151 4152

	if (len == 0)
		return -EINVAL;

J
Josef Bacik 已提交
4153 4154 4155 4156 4157
	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
	path->leave_spinning = 1;

4158 4159 4160
	start = ALIGN(start, BTRFS_I(inode)->root->sectorsize);
	len = ALIGN(len, BTRFS_I(inode)->root->sectorsize);

4161 4162 4163 4164
	/*
	 * 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
4165
	ret = btrfs_lookup_file_extent(NULL, BTRFS_I(inode)->root,
L
Li Zefan 已提交
4166
				       path, btrfs_ino(inode), -1, 0);
J
Josef Bacik 已提交
4167 4168 4169 4170 4171 4172 4173 4174 4175
	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]);
	found_type = btrfs_key_type(&found_key);

4176
	/* No extents, but there might be delalloc bits */
L
Li Zefan 已提交
4177
	if (found_key.objectid != btrfs_ino(inode) ||
J
Josef Bacik 已提交
4178
	    found_type != BTRFS_EXTENT_DATA_KEY) {
4179 4180 4181 4182 4183 4184 4185 4186 4187 4188 4189
		/* 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
4190
	}
4191
	btrfs_release_path(path);
J
Josef Bacik 已提交
4192

4193 4194 4195 4196 4197 4198 4199 4200 4201 4202
	/*
	 * 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
4203
	lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len - 1, 0,
4204
			 &cached_state);
4205

4206
	em = get_extent_skip_holes(inode, start, last_for_get_extent,
4207
				   get_extent);
Y
Yehuda Sadeh 已提交
4208 4209 4210 4211 4212 4213
	if (!em)
		goto out;
	if (IS_ERR(em)) {
		ret = PTR_ERR(em);
		goto out;
	}
J
Josef Bacik 已提交
4214

Y
Yehuda Sadeh 已提交
4215
	while (!end) {
4216
		u64 offset_in_extent = 0;
4217 4218 4219 4220 4221 4222 4223 4224 4225 4226 4227 4228

		/* 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
4229

4230 4231
		/*
		 * record the offset from the start of the extent
4232 4233 4234
		 * 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.
4235
		 */
4236 4237
		if (!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
			offset_in_extent = em_start - em->start;
4238
		em_end = extent_map_end(em);
4239
		em_len = em_end - em_start;
Y
Yehuda Sadeh 已提交
4240 4241 4242
		disko = 0;
		flags = 0;

4243 4244 4245 4246 4247 4248 4249
		/*
		 * bump off for our next call to get_extent
		 */
		off = extent_map_end(em);
		if (off >= max)
			end = 1;

4250
		if (em->block_start == EXTENT_MAP_LAST_BYTE) {
Y
Yehuda Sadeh 已提交
4251 4252
			end = 1;
			flags |= FIEMAP_EXTENT_LAST;
4253
		} else if (em->block_start == EXTENT_MAP_INLINE) {
Y
Yehuda Sadeh 已提交
4254 4255
			flags |= (FIEMAP_EXTENT_DATA_INLINE |
				  FIEMAP_EXTENT_NOT_ALIGNED);
4256
		} else if (em->block_start == EXTENT_MAP_DELALLOC) {
Y
Yehuda Sadeh 已提交
4257 4258
			flags |= (FIEMAP_EXTENT_DELALLOC |
				  FIEMAP_EXTENT_UNKNOWN);
4259
		} else {
4260 4261
			unsigned long ref_cnt = 0;

4262
			disko = em->block_start + offset_in_extent;
4263 4264 4265 4266 4267 4268 4269 4270 4271 4272 4273 4274 4275 4276 4277

			/*
			 * 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
4278 4279 4280 4281 4282 4283
		}
		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
			flags |= FIEMAP_EXTENT_ENCODED;

		free_extent_map(em);
		em = NULL;
4284 4285
		if ((em_start >= last) || em_len == (u64)-1 ||
		   (last == (u64)-1 && isize <= em_end)) {
Y
Yehuda Sadeh 已提交
4286 4287 4288 4289
			flags |= FIEMAP_EXTENT_LAST;
			end = 1;
		}

4290 4291 4292 4293 4294 4295 4296 4297
		/* 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
4298 4299 4300
			flags |= FIEMAP_EXTENT_LAST;
			end = 1;
		}
4301 4302 4303 4304
		ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
					      em_len, flags);
		if (ret)
			goto out_free;
Y
Yehuda Sadeh 已提交
4305 4306 4307 4308
	}
out_free:
	free_extent_map(em);
out:
4309
	btrfs_free_path(path);
L
Liu Bo 已提交
4310
	unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len - 1,
4311
			     &cached_state, GFP_NOFS);
Y
Yehuda Sadeh 已提交
4312 4313 4314
	return ret;
}

4315 4316
static void __free_extent_buffer(struct extent_buffer *eb)
{
4317
	btrfs_leak_debug_del(&eb->leak_list);
4318 4319 4320
	kmem_cache_free(extent_buffer_cache, eb);
}

4321
int extent_buffer_under_io(struct extent_buffer *eb)
4322 4323 4324 4325 4326 4327 4328 4329 4330 4331 4332 4333 4334 4335 4336 4337 4338 4339 4340 4341 4342 4343 4344 4345 4346 4347 4348 4349 4350 4351 4352 4353 4354 4355 4356 4357 4358 4359 4360 4361 4362 4363 4364 4365 4366 4367 4368 4369 4370 4371 4372 4373 4374 4375 4376 4377 4378 4379 4380 4381 4382 4383 4384 4385 4386 4387 4388 4389 4390
{
	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);
}

4391 4392 4393
static struct extent_buffer *
__alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
		      unsigned long len, gfp_t mask)
4394 4395 4396 4397
{
	struct extent_buffer *eb = NULL;

	eb = kmem_cache_zalloc(extent_buffer_cache, mask);
T
Tsutomu Itoh 已提交
4398 4399
	if (eb == NULL)
		return NULL;
4400 4401
	eb->start = start;
	eb->len = len;
4402
	eb->fs_info = fs_info;
4403
	eb->bflags = 0;
4404 4405 4406 4407 4408 4409 4410
	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);
4411
	eb->lock_nested = 0;
4412 4413
	init_waitqueue_head(&eb->write_lock_wq);
	init_waitqueue_head(&eb->read_lock_wq);
4414

4415 4416
	btrfs_leak_debug_add(&eb->leak_list, &buffers);

4417
	spin_lock_init(&eb->refs_lock);
4418
	atomic_set(&eb->refs, 1);
4419
	atomic_set(&eb->io_pages, 0);
4420

4421 4422 4423 4424 4425 4426
	/*
	 * 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);
4427 4428 4429 4430

	return eb;
}

4431 4432 4433 4434 4435 4436 4437
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);

4438
	new = __alloc_extent_buffer(NULL, src->start, src->len, GFP_NOFS);
4439 4440 4441 4442
	if (new == NULL)
		return NULL;

	for (i = 0; i < num_pages; i++) {
4443
		p = alloc_page(GFP_NOFS);
4444 4445 4446 4447
		if (!p) {
			btrfs_release_extent_buffer(new);
			return NULL;
		}
4448 4449 4450 4451 4452 4453 4454 4455 4456 4457 4458 4459 4460 4461 4462 4463 4464 4465 4466
		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;

4467
	eb = __alloc_extent_buffer(NULL, start, len, GFP_NOFS);
4468 4469 4470 4471
	if (!eb)
		return NULL;

	for (i = 0; i < num_pages; i++) {
4472
		eb->pages[i] = alloc_page(GFP_NOFS);
4473 4474 4475 4476 4477 4478 4479 4480 4481
		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:
4482 4483
	for (; i > 0; i--)
		__free_page(eb->pages[i - 1]);
4484 4485 4486 4487
	__free_extent_buffer(eb);
	return NULL;
}

4488 4489
static void check_buffer_tree_ref(struct extent_buffer *eb)
{
4490
	int refs;
4491 4492 4493 4494 4495 4496 4497 4498 4499 4500 4501 4502 4503 4504 4505 4506 4507 4508 4509 4510
	/* 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.
	 */
4511 4512 4513 4514
	refs = atomic_read(&eb->refs);
	if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
		return;

4515 4516
	spin_lock(&eb->refs_lock);
	if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
4517
		atomic_inc(&eb->refs);
4518
	spin_unlock(&eb->refs_lock);
4519 4520
}

4521 4522 4523 4524
static void mark_extent_buffer_accessed(struct extent_buffer *eb)
{
	unsigned long num_pages, i;

4525 4526
	check_buffer_tree_ref(eb);

4527 4528 4529 4530 4531 4532 4533
	num_pages = num_extent_pages(eb->start, eb->len);
	for (i = 0; i < num_pages; i++) {
		struct page *p = extent_buffer_page(eb, i);
		mark_page_accessed(p);
	}
}

4534 4535
struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
					 u64 start)
4536 4537 4538 4539
{
	struct extent_buffer *eb;

	rcu_read_lock();
4540 4541
	eb = radix_tree_lookup(&fs_info->buffer_radix,
			       start >> PAGE_CACHE_SHIFT);
4542 4543 4544 4545 4546 4547 4548 4549 4550 4551
	if (eb && atomic_inc_not_zero(&eb->refs)) {
		rcu_read_unlock();
		mark_extent_buffer_accessed(eb);
		return eb;
	}
	rcu_read_unlock();

	return NULL;
}

4552 4553 4554 4555 4556 4557 4558 4559 4560 4561 4562 4563 4564 4565 4566 4567 4568 4569 4570 4571 4572 4573 4574 4575 4576 4577 4578 4579 4580 4581 4582 4583 4584 4585 4586 4587 4588 4589 4590 4591 4592 4593 4594 4595 4596 4597 4598
#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

4599
struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
4600
					  u64 start, unsigned long len)
4601 4602 4603 4604 4605
{
	unsigned long num_pages = num_extent_pages(start, len);
	unsigned long i;
	unsigned long index = start >> PAGE_CACHE_SHIFT;
	struct extent_buffer *eb;
4606
	struct extent_buffer *exists = NULL;
4607
	struct page *p;
4608
	struct address_space *mapping = fs_info->btree_inode->i_mapping;
4609
	int uptodate = 1;
4610
	int ret;
4611

4612
	eb = find_extent_buffer(fs_info, start);
4613
	if (eb)
4614 4615
		return eb;

4616
	eb = __alloc_extent_buffer(fs_info, start, len, GFP_NOFS);
4617
	if (!eb)
4618 4619
		return NULL;

4620
	for (i = 0; i < num_pages; i++, index++) {
4621
		p = find_or_create_page(mapping, index, GFP_NOFS);
4622
		if (!p)
4623
			goto free_eb;
J
Josef Bacik 已提交
4624 4625 4626 4627 4628 4629 4630 4631 4632 4633 4634 4635 4636 4637

		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);
4638
				page_cache_release(p);
4639
				mark_extent_buffer_accessed(exists);
J
Josef Bacik 已提交
4640 4641 4642
				goto free_eb;
			}

4643
			/*
J
Josef Bacik 已提交
4644 4645 4646 4647
			 * Do this so attach doesn't complain and we need to
			 * drop the ref the old guy had.
			 */
			ClearPagePrivate(p);
4648
			WARN_ON(PageDirty(p));
J
Josef Bacik 已提交
4649
			page_cache_release(p);
4650
		}
J
Josef Bacik 已提交
4651 4652
		attach_extent_buffer_page(eb, p);
		spin_unlock(&mapping->private_lock);
4653
		WARN_ON(PageDirty(p));
4654
		mark_page_accessed(p);
4655
		eb->pages[i] = p;
4656 4657
		if (!PageUptodate(p))
			uptodate = 0;
C
Chris Mason 已提交
4658 4659 4660 4661 4662

		/*
		 * see below about how we avoid a nasty race with release page
		 * and why we unlock later
		 */
4663 4664
	}
	if (uptodate)
4665
		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4666
again:
4667 4668 4669 4670
	ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
	if (ret)
		goto free_eb;

4671 4672 4673 4674
	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);
4675
	radix_tree_preload_end();
4676
	if (ret == -EEXIST) {
4677
		exists = find_extent_buffer(fs_info, start);
4678 4679 4680
		if (exists)
			goto free_eb;
		else
4681
			goto again;
4682 4683
	}
	/* add one reference for the tree */
4684
	check_buffer_tree_ref(eb);
4685
	set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
C
Chris Mason 已提交
4686 4687 4688 4689 4690 4691 4692 4693 4694 4695

	/*
	 * 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
	 */
4696 4697 4698 4699 4700 4701 4702
	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]);
4703 4704
	return eb;

4705
free_eb:
4706 4707 4708 4709
	for (i = 0; i < num_pages; i++) {
		if (eb->pages[i])
			unlock_page(eb->pages[i]);
	}
C
Chris Mason 已提交
4710

4711
	WARN_ON(!atomic_dec_and_test(&eb->refs));
4712
	btrfs_release_extent_buffer(eb);
4713
	return exists;
4714 4715
}

4716 4717 4718 4719 4720 4721 4722 4723 4724
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 */
4725
static int release_extent_buffer(struct extent_buffer *eb)
4726 4727 4728
{
	WARN_ON(atomic_read(&eb->refs) == 0);
	if (atomic_dec_and_test(&eb->refs)) {
4729
		if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
4730
			struct btrfs_fs_info *fs_info = eb->fs_info;
4731

4732
			spin_unlock(&eb->refs_lock);
4733

4734 4735
			spin_lock(&fs_info->buffer_lock);
			radix_tree_delete(&fs_info->buffer_radix,
4736
					  eb->start >> PAGE_CACHE_SHIFT);
4737
			spin_unlock(&fs_info->buffer_lock);
4738 4739
		} else {
			spin_unlock(&eb->refs_lock);
4740
		}
4741 4742 4743 4744

		/* 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);
4745
		return 1;
4746 4747
	}
	spin_unlock(&eb->refs_lock);
4748 4749

	return 0;
4750 4751
}

4752 4753
void free_extent_buffer(struct extent_buffer *eb)
{
4754 4755
	int refs;
	int old;
4756 4757 4758
	if (!eb)
		return;

4759 4760 4761 4762 4763 4764 4765 4766 4767
	while (1) {
		refs = atomic_read(&eb->refs);
		if (refs <= 3)
			break;
		old = atomic_cmpxchg(&eb->refs, refs, refs - 1);
		if (old == refs)
			return;
	}

4768
	spin_lock(&eb->refs_lock);
4769 4770 4771 4772
	if (atomic_read(&eb->refs) == 2 &&
	    test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))
		atomic_dec(&eb->refs);

4773 4774
	if (atomic_read(&eb->refs) == 2 &&
	    test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
4775
	    !extent_buffer_under_io(eb) &&
4776 4777 4778 4779 4780 4781 4782
	    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.
	 */
4783
	release_extent_buffer(eb);
4784 4785 4786 4787 4788
}

void free_extent_buffer_stale(struct extent_buffer *eb)
{
	if (!eb)
4789 4790
		return;

4791 4792 4793
	spin_lock(&eb->refs_lock);
	set_bit(EXTENT_BUFFER_STALE, &eb->bflags);

4794
	if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
4795 4796
	    test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
		atomic_dec(&eb->refs);
4797
	release_extent_buffer(eb);
4798 4799
}

4800
void clear_extent_buffer_dirty(struct extent_buffer *eb)
4801 4802 4803 4804 4805 4806 4807 4808 4809
{
	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);
4810
		if (!PageDirty(page))
C
Chris Mason 已提交
4811 4812
			continue;

4813
		lock_page(page);
C
Chris Mason 已提交
4814 4815
		WARN_ON(!PagePrivate(page));

4816
		clear_page_dirty_for_io(page);
4817
		spin_lock_irq(&page->mapping->tree_lock);
4818 4819 4820 4821 4822
		if (!PageDirty(page)) {
			radix_tree_tag_clear(&page->mapping->page_tree,
						page_index(page),
						PAGECACHE_TAG_DIRTY);
		}
4823
		spin_unlock_irq(&page->mapping->tree_lock);
4824
		ClearPageError(page);
4825
		unlock_page(page);
4826
	}
4827
	WARN_ON(atomic_read(&eb->refs) == 0);
4828 4829
}

4830
int set_extent_buffer_dirty(struct extent_buffer *eb)
4831 4832 4833
{
	unsigned long i;
	unsigned long num_pages;
4834
	int was_dirty = 0;
4835

4836 4837
	check_buffer_tree_ref(eb);

4838
	was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
4839

4840
	num_pages = num_extent_pages(eb->start, eb->len);
4841
	WARN_ON(atomic_read(&eb->refs) == 0);
4842 4843
	WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));

4844
	for (i = 0; i < num_pages; i++)
4845
		set_page_dirty(extent_buffer_page(eb, i));
4846
	return was_dirty;
4847 4848
}

4849
int clear_extent_buffer_uptodate(struct extent_buffer *eb)
4850 4851 4852 4853 4854
{
	unsigned long i;
	struct page *page;
	unsigned long num_pages;

4855
	clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4856
	num_pages = num_extent_pages(eb->start, eb->len);
4857 4858
	for (i = 0; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
C
Chris Mason 已提交
4859 4860
		if (page)
			ClearPageUptodate(page);
4861 4862 4863 4864
	}
	return 0;
}

4865
int set_extent_buffer_uptodate(struct extent_buffer *eb)
4866 4867 4868 4869 4870
{
	unsigned long i;
	struct page *page;
	unsigned long num_pages;

4871
	set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4872 4873 4874 4875 4876 4877 4878 4879
	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;
}

4880
int extent_buffer_uptodate(struct extent_buffer *eb)
4881
{
4882
	return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4883 4884 4885
}

int read_extent_buffer_pages(struct extent_io_tree *tree,
4886
			     struct extent_buffer *eb, u64 start, int wait,
4887
			     get_extent_t *get_extent, int mirror_num)
4888 4889 4890 4891 4892 4893
{
	unsigned long i;
	unsigned long start_i;
	struct page *page;
	int err;
	int ret = 0;
4894 4895
	int locked_pages = 0;
	int all_uptodate = 1;
4896
	unsigned long num_pages;
4897
	unsigned long num_reads = 0;
4898
	struct bio *bio = NULL;
C
Chris Mason 已提交
4899
	unsigned long bio_flags = 0;
4900

4901
	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
4902 4903 4904 4905 4906 4907 4908 4909 4910 4911 4912 4913 4914
		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);
4915
		if (wait == WAIT_NONE) {
4916
			if (!trylock_page(page))
4917
				goto unlock_exit;
4918 4919 4920
		} else {
			lock_page(page);
		}
4921
		locked_pages++;
4922 4923
		if (!PageUptodate(page)) {
			num_reads++;
4924
			all_uptodate = 0;
4925
		}
4926 4927 4928
	}
	if (all_uptodate) {
		if (start_i == 0)
4929
			set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
4930 4931 4932
		goto unlock_exit;
	}

4933
	clear_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
4934
	eb->read_mirror = 0;
4935
	atomic_set(&eb->io_pages, num_reads);
4936 4937 4938
	for (i = start_i; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
		if (!PageUptodate(page)) {
4939
			ClearPageError(page);
4940
			err = __extent_read_full_page(tree, page,
4941
						      get_extent, &bio,
4942 4943
						      mirror_num, &bio_flags,
						      READ | REQ_META);
C
Chris Mason 已提交
4944
			if (err)
4945 4946 4947 4948 4949 4950
				ret = err;
		} else {
			unlock_page(page);
		}
	}

4951
	if (bio) {
4952 4953
		err = submit_one_bio(READ | REQ_META, bio, mirror_num,
				     bio_flags);
4954 4955
		if (err)
			return err;
4956
	}
4957

4958
	if (ret || wait != WAIT_COMPLETE)
4959
		return ret;
C
Chris Mason 已提交
4960

4961 4962 4963
	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
4964
		if (!PageUptodate(page))
4965 4966
			ret = -EIO;
	}
C
Chris Mason 已提交
4967

4968
	return ret;
4969 4970 4971

unlock_exit:
	i = start_i;
C
Chris Mason 已提交
4972
	while (locked_pages > 0) {
4973 4974 4975 4976 4977 4978
		page = extent_buffer_page(eb, i);
		i++;
		unlock_page(page);
		locked_pages--;
	}
	return ret;
4979 4980 4981 4982 4983 4984 4985 4986 4987 4988 4989 4990 4991 4992 4993 4994 4995
}

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);

4996
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
4997

C
Chris Mason 已提交
4998
	while (len > 0) {
4999 5000 5001
		page = extent_buffer_page(eb, i);

		cur = min(len, (PAGE_CACHE_SIZE - offset));
5002
		kaddr = page_address(page);
5003 5004 5005 5006 5007 5008 5009 5010 5011 5012
		memcpy(dst, kaddr + offset, cur);

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

int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
5013
			       unsigned long min_len, char **map,
5014
			       unsigned long *map_start,
5015
			       unsigned long *map_len)
5016 5017 5018 5019 5020 5021 5022 5023 5024 5025 5026 5027 5028 5029 5030 5031 5032 5033 5034
{
	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
5035

5036
	if (start + min_len > eb->len) {
J
Julia Lawall 已提交
5037
		WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
5038 5039
		       "wanted %lu %lu\n",
		       eb->start, eb->len, start, min_len);
5040
		return -EINVAL;
5041 5042 5043
	}

	p = extent_buffer_page(eb, i);
5044
	kaddr = page_address(p);
5045 5046 5047 5048 5049 5050 5051 5052 5053 5054 5055 5056 5057 5058 5059 5060 5061 5062 5063 5064 5065
	*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);

5066
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5067

C
Chris Mason 已提交
5068
	while (len > 0) {
5069 5070 5071 5072
		page = extent_buffer_page(eb, i);

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

5073
		kaddr = page_address(page);
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
		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);

5100
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5101

C
Chris Mason 已提交
5102
	while (len > 0) {
5103 5104 5105 5106
		page = extent_buffer_page(eb, i);
		WARN_ON(!PageUptodate(page));

		cur = min(len, PAGE_CACHE_SIZE - offset);
5107
		kaddr = page_address(page);
5108 5109 5110 5111 5112 5113 5114 5115 5116 5117 5118 5119 5120 5121 5122 5123 5124 5125 5126 5127 5128 5129
		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);

5130
	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
5131

C
Chris Mason 已提交
5132
	while (len > 0) {
5133 5134 5135 5136
		page = extent_buffer_page(eb, i);
		WARN_ON(!PageUptodate(page));

		cur = min(len, PAGE_CACHE_SIZE - offset);
5137
		kaddr = page_address(page);
5138 5139 5140 5141 5142 5143 5144 5145 5146 5147 5148 5149 5150 5151 5152 5153 5154 5155 5156 5157 5158 5159 5160
		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) &
5161
		(PAGE_CACHE_SIZE - 1);
5162

C
Chris Mason 已提交
5163
	while (len > 0) {
5164 5165 5166 5167 5168
		page = extent_buffer_page(dst, i);
		WARN_ON(!PageUptodate(page));

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

5169
		kaddr = page_address(page);
5170 5171 5172 5173 5174 5175 5176 5177 5178
		read_extent_buffer(src, kaddr + offset, src_offset, cur);

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

5179 5180 5181 5182 5183 5184
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;
}

5185 5186 5187 5188
static void copy_pages(struct page *dst_page, struct page *src_page,
		       unsigned long dst_off, unsigned long src_off,
		       unsigned long len)
{
5189
	char *dst_kaddr = page_address(dst_page);
5190
	char *src_kaddr;
5191
	int must_memmove = 0;
5192

5193
	if (dst_page != src_page) {
5194
		src_kaddr = page_address(src_page);
5195
	} else {
5196
		src_kaddr = dst_kaddr;
5197 5198
		if (areas_overlap(src_off, dst_off, len))
			must_memmove = 1;
5199
	}
5200

5201 5202 5203 5204
	if (must_memmove)
		memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
	else
		memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
5205 5206 5207 5208 5209 5210 5211 5212 5213 5214 5215 5216 5217
}

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) {
5218
		printk(KERN_ERR "BTRFS: memmove bogus src_offset %lu move "
C
Chris Mason 已提交
5219
		       "len %lu dst len %lu\n", src_offset, len, dst->len);
5220 5221 5222
		BUG_ON(1);
	}
	if (dst_offset + len > dst->len) {
5223
		printk(KERN_ERR "BTRFS: memmove bogus dst_offset %lu move "
C
Chris Mason 已提交
5224
		       "len %lu dst len %lu\n", dst_offset, len, dst->len);
5225 5226 5227
		BUG_ON(1);
	}

C
Chris Mason 已提交
5228
	while (len > 0) {
5229
		dst_off_in_page = (start_offset + dst_offset) &
5230
			(PAGE_CACHE_SIZE - 1);
5231
		src_off_in_page = (start_offset + src_offset) &
5232
			(PAGE_CACHE_SIZE - 1);
5233 5234 5235 5236 5237 5238 5239 5240 5241 5242 5243 5244 5245 5246 5247 5248 5249 5250 5251 5252 5253 5254 5255 5256 5257 5258 5259 5260 5261 5262 5263 5264

		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) {
5265
		printk(KERN_ERR "BTRFS: memmove bogus src_offset %lu move "
C
Chris Mason 已提交
5266
		       "len %lu len %lu\n", src_offset, len, dst->len);
5267 5268 5269
		BUG_ON(1);
	}
	if (dst_offset + len > dst->len) {
5270
		printk(KERN_ERR "BTRFS: memmove bogus dst_offset %lu move "
C
Chris Mason 已提交
5271
		       "len %lu len %lu\n", dst_offset, len, dst->len);
5272 5273
		BUG_ON(1);
	}
5274
	if (dst_offset < src_offset) {
5275 5276 5277
		memcpy_extent_buffer(dst, dst_offset, src_offset, len);
		return;
	}
C
Chris Mason 已提交
5278
	while (len > 0) {
5279 5280 5281 5282
		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) &
5283
			(PAGE_CACHE_SIZE - 1);
5284
		src_off_in_page = (start_offset + src_end) &
5285
			(PAGE_CACHE_SIZE - 1);
5286 5287 5288

		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
5289
		copy_pages(extent_buffer_page(dst, dst_i),
5290 5291 5292 5293 5294 5295 5296 5297 5298
			   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;
	}
}
5299

5300
int try_release_extent_buffer(struct page *page)
5301
{
5302 5303
	struct extent_buffer *eb;

5304 5305 5306 5307 5308 5309 5310
	/*
	 * 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
5311
		return 1;
5312
	}
5313

5314 5315
	eb = (struct extent_buffer *)page->private;
	BUG_ON(!eb);
5316 5317

	/*
5318 5319 5320
	 * 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.
5321
	 */
5322
	spin_lock(&eb->refs_lock);
5323
	if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
5324 5325 5326
		spin_unlock(&eb->refs_lock);
		spin_unlock(&page->mapping->private_lock);
		return 0;
5327
	}
5328
	spin_unlock(&page->mapping->private_lock);
5329

5330
	/*
5331 5332
	 * 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.
5333
	 */
5334 5335 5336
	if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
		spin_unlock(&eb->refs_lock);
		return 0;
5337
	}
5338

5339
	return release_extent_buffer(eb);
5340
}