extent_io.c 93.4 KB
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#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/bio.h>
#include <linux/mm.h>
#include <linux/gfp.h>
#include <linux/pagemap.h>
#include <linux/page-flags.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/blkdev.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/pagevec.h>
#include "extent_io.h"
#include "extent_map.h"
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#include "compat.h"
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#include "ctree.h"
#include "btrfs_inode.h"
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static struct kmem_cache *extent_state_cache;
static struct kmem_cache *extent_buffer_cache;

static LIST_HEAD(buffers);
static LIST_HEAD(states);
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#define LEAK_DEBUG 0
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#if LEAK_DEBUG
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static DEFINE_SPINLOCK(leak_lock);
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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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	/* 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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};

int __init extent_io_init(void)
{
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	extent_state_cache = kmem_cache_create("extent_state",
			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("extent_buffers",
			sizeof(struct extent_buffer), 0,
			SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
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	if (!extent_buffer_cache)
		goto free_state_cache;
	return 0;

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

void extent_io_exit(void)
{
	struct extent_state *state;
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	struct extent_buffer *eb;
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	while (!list_empty(&states)) {
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		state = list_entry(states.next, struct extent_state, leak_list);
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		printk(KERN_ERR "btrfs state leak: start %llu end %llu "
		       "state %lu in tree %p refs %d\n",
		       (unsigned long long)state->start,
		       (unsigned long long)state->end,
		       state->state, state->tree, atomic_read(&state->refs));
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		list_del(&state->leak_list);
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		kmem_cache_free(extent_state_cache, state);

	}

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	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 "
		       "refs %d\n", (unsigned long long)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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	if (extent_state_cache)
		kmem_cache_destroy(extent_state_cache);
	if (extent_buffer_cache)
		kmem_cache_destroy(extent_buffer_cache);
}

void extent_io_tree_init(struct extent_io_tree *tree,
			  struct address_space *mapping, gfp_t mask)
{
	tree->state.rb_node = NULL;
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	tree->buffer.rb_node = NULL;
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	tree->ops = NULL;
	tree->dirty_bytes = 0;
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	spin_lock_init(&tree->lock);
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	spin_lock_init(&tree->buffer_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;
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#if LEAK_DEBUG
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	unsigned long flags;
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#endif
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	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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#if LEAK_DEBUG
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	spin_lock_irqsave(&leak_lock, flags);
	list_add(&state->leak_list, &states);
	spin_unlock_irqrestore(&leak_lock, flags);
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#endif
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	atomic_set(&state->refs, 1);
	init_waitqueue_head(&state->wq);
	return state;
}

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static 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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#if LEAK_DEBUG
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		unsigned long flags;
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#endif
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		WARN_ON(state->tree);
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#if LEAK_DEBUG
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		spin_lock_irqsave(&leak_lock, flags);
		list_del(&state->leak_list);
		spin_unlock_irqrestore(&leak_lock, flags);
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#endif
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		kmem_cache_free(extent_state_cache, state);
	}
}

static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
				   struct rb_node *node)
{
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	struct rb_node **p = &root->rb_node;
	struct rb_node *parent = NULL;
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	struct tree_entry *entry;

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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;
	}

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

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

	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(struct extent_io_tree *tree,
					  u64 offset)
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{
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	struct rb_node *prev = NULL;
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	struct rb_node *ret;
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	ret = __etree_search(tree, offset, &prev, NULL);
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	if (!ret)
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		return prev;
	return ret;
}

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static struct extent_buffer *buffer_tree_insert(struct extent_io_tree *tree,
					  u64 offset, struct rb_node *node)
{
	struct rb_root *root = &tree->buffer;
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	struct rb_node **p = &root->rb_node;
	struct rb_node *parent = NULL;
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	struct extent_buffer *eb;

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	while (*p) {
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		parent = *p;
		eb = rb_entry(parent, struct extent_buffer, rb_node);

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

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

static struct extent_buffer *buffer_search(struct extent_io_tree *tree,
					   u64 offset)
{
	struct rb_root *root = &tree->buffer;
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	struct rb_node *n = root->rb_node;
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	struct extent_buffer *eb;

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	while (n) {
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		eb = rb_entry(n, struct extent_buffer, rb_node);
		if (offset < eb->start)
			n = n->rb_left;
		else if (offset > eb->start)
			n = n->rb_right;
		else
			return eb;
	}
	return 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.
 */
static int merge_state(struct extent_io_tree *tree,
		       struct extent_state *state)
{
	struct extent_state *other;
	struct rb_node *other_node;

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	if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
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		return 0;

	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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			other->start = state->start;
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			state->tree = NULL;
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			rb_erase(&state->rb_node, &tree->state);
			free_extent_state(state);
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			state = NULL;
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		}
	}
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	return 0;
}

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static int set_state_cb(struct extent_io_tree *tree,
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			 struct extent_state *state,
			 unsigned long bits)
{
	if (tree->ops && tree->ops->set_bit_hook) {
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		return tree->ops->set_bit_hook(tree->mapping->host,
					       state->start, state->end,
					       state->state, bits);
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	}
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	return 0;
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}

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

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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,
			int bits)
{
	struct rb_node *node;
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	int ret;
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	if (end < start) {
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		printk(KERN_ERR "btrfs end < start %llu %llu\n",
		       (unsigned long long)end,
		       (unsigned long long)start);
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		WARN_ON(1);
	}
	state->start = start;
	state->end = end;
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	ret = set_state_cb(tree, state, bits);
	if (ret)
		return ret;

	if (bits & EXTENT_DIRTY)
		tree->dirty_bytes += end - start + 1;
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	state->state |= bits;
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	node = tree_insert(&tree->state, end, &state->rb_node);
	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 "
		       "%llu %llu\n", (unsigned long long)found->start,
		       (unsigned long long)found->end,
		       (unsigned long long)start, (unsigned long long)end);
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		free_extent_state(state);
		return -EEXIST;
	}
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	state->tree = tree;
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	merge_state(tree, state);
	return 0;
}

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static int split_cb(struct extent_io_tree *tree, struct extent_state *orig,
		     u64 split)
{
	if (tree->ops && tree->ops->split_extent_hook)
		return tree->ops->split_extent_hook(tree->mapping->host,
						    orig, split);
	return 0;
}

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

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

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

/*
 * utility function to clear some bits in an extent state struct.
 * it will optionally wake up any one waiting on this state (wake == 1), or
 * forcibly remove the state from the tree (delete == 1).
 *
 * If no bits are set on the state struct after clearing things, the
 * struct is freed and removed from the tree
 */
static int clear_state_bit(struct extent_io_tree *tree,
			    struct extent_state *state, int bits, int wake,
			    int delete)
{
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	int bits_to_clear = bits & ~EXTENT_DO_ACCOUNTING;
	int ret = state->state & bits_to_clear;
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	if ((bits & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
		u64 range = state->end - state->start + 1;
		WARN_ON(range > tree->dirty_bytes);
		tree->dirty_bytes -= range;
	}
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	clear_state_cb(tree, state, bits);
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	state->state &= ~bits_to_clear;
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	if (wake)
		wake_up(&state->wq);
	if (delete || state->state == 0) {
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		if (state->tree) {
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			clear_state_cb(tree, state, state->state);
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			rb_erase(&state->rb_node, &tree->state);
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			state->tree = NULL;
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			free_extent_state(state);
		} else {
			WARN_ON(1);
		}
	} else {
		merge_state(tree, state);
	}
	return ret;
}

/*
 * 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.
 *
 * This takes the tree lock, and returns < 0 on error, > 0 if any of the
 * bits were already set, or zero if none of the bits were already set.
 */
int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
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		     int bits, int wake, int delete,
		     struct extent_state **cached_state,
		     gfp_t mask)
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{
	struct extent_state *state;
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	struct extent_state *cached;
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	struct extent_state *prealloc = NULL;
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	struct rb_node *next_node;
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	struct rb_node *node;
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	u64 last_end;
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	int err;
	int set = 0;

again:
	if (!prealloc && (mask & __GFP_WAIT)) {
		prealloc = alloc_extent_state(mask);
		if (!prealloc)
			return -ENOMEM;
	}

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	spin_lock(&tree->lock);
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	if (cached_state) {
		cached = *cached_state;
		*cached_state = NULL;
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		cached_state = NULL;
		if (cached && cached->tree && cached->start == start) {
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			atomic_dec(&cached->refs);
			state = cached;
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			goto hit_next;
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		}
		free_extent_state(cached);
	}
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	/*
	 * this search will find the extents that end after
	 * our range starts
	 */
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	node = tree_search(tree, start);
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	if (!node)
		goto out;
	state = rb_entry(node, struct extent_state, rb_node);
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hit_next:
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	if (state->start > end)
		goto out;
	WARN_ON(state->end < start);
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	last_end = state->end;
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	/*
	 *     | ---- 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) {
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		if (!prealloc)
			prealloc = alloc_extent_state(GFP_ATOMIC);
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		err = split_state(tree, state, prealloc, start);
		BUG_ON(err == -EEXIST);
		prealloc = NULL;
		if (err)
			goto out;
		if (state->end <= end) {
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			set |= clear_state_bit(tree, state, bits, wake,
					       delete);
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			if (last_end == (u64)-1)
				goto out;
			start = last_end + 1;
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		}
		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) {
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		if (!prealloc)
			prealloc = alloc_extent_state(GFP_ATOMIC);
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		err = split_state(tree, state, prealloc, end + 1);
		BUG_ON(err == -EEXIST);
		if (wake)
			wake_up(&state->wq);
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		set |= clear_state_bit(tree, prealloc, bits, wake, delete);

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		prealloc = NULL;
		goto out;
	}
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	if (state->end < end && prealloc && !need_resched())
		next_node = rb_next(&state->rb_node);
	else
		next_node = NULL;
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	set |= clear_state_bit(tree, state, bits, wake, delete);
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	if (last_end == (u64)-1)
		goto out;
	start = last_end + 1;
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	if (start <= end && next_node) {
		state = rb_entry(next_node, struct extent_state,
				 rb_node);
		if (state->start == start)
			goto hit_next;
	}
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	goto search_again;

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

	return set;

search_again:
	if (start > end)
		goto out;
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	spin_unlock(&tree->lock);
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	if (mask & __GFP_WAIT)
		cond_resched();
	goto again;
}

static int wait_on_state(struct extent_io_tree *tree,
			 struct extent_state *state)
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		__releases(tree->lock)
		__acquires(tree->lock)
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{
	DEFINE_WAIT(wait);
	prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
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	spin_unlock(&tree->lock);
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	schedule();
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	spin_lock(&tree->lock);
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	finish_wait(&state->wq, &wait);
	return 0;
}

/*
 * 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
 */
int wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits)
{
	struct extent_state *state;
	struct rb_node *node;

660
	spin_lock(&tree->lock);
661 662 663 664 665 666
again:
	while (1) {
		/*
		 * this search will find all the extents that end after
		 * our range starts
		 */
667
		node = tree_search(tree, start);
668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688
		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;

		if (need_resched()) {
689
			spin_unlock(&tree->lock);
690
			cond_resched();
691
			spin_lock(&tree->lock);
692 693 694
		}
	}
out:
695
	spin_unlock(&tree->lock);
696 697 698
	return 0;
}

J
Josef Bacik 已提交
699
static int set_state_bits(struct extent_io_tree *tree,
700 701 702
			   struct extent_state *state,
			   int bits)
{
J
Josef Bacik 已提交
703 704 705 706 707 708
	int ret;

	ret = set_state_cb(tree, state, bits);
	if (ret)
		return ret;

709 710 711 712
	if ((bits & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
		u64 range = state->end - state->start + 1;
		tree->dirty_bytes += range;
	}
C
Chris Mason 已提交
713
	state->state |= bits;
J
Josef Bacik 已提交
714 715

	return 0;
716 717
}

718 719 720 721 722 723 724 725 726 727 728
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);
		}
	}
}

729
/*
730 731
 * 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.
732
 *
733 734 735
 * 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.
736
 *
737
 * [start, end] is inclusive This takes the tree lock.
738
 */
739

C
Chris Mason 已提交
740
static int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
741
			  int bits, int exclusive_bits, u64 *failed_start,
742
			  struct extent_state **cached_state,
C
Chris Mason 已提交
743
			  gfp_t mask)
744 745 746 747 748 749 750
{
	struct extent_state *state;
	struct extent_state *prealloc = NULL;
	struct rb_node *node;
	int err = 0;
	u64 last_start;
	u64 last_end;
751

752 753 754 755 756 757 758
again:
	if (!prealloc && (mask & __GFP_WAIT)) {
		prealloc = alloc_extent_state(mask);
		if (!prealloc)
			return -ENOMEM;
	}

759
	spin_lock(&tree->lock);
760 761 762 763 764 765 766
	if (cached_state && *cached_state) {
		state = *cached_state;
		if (state->start == start && state->tree) {
			node = &state->rb_node;
			goto hit_next;
		}
	}
767 768 769 770
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
771
	node = tree_search(tree, start);
772 773 774 775 776 777 778
	if (!node) {
		err = insert_state(tree, prealloc, start, end, bits);
		prealloc = NULL;
		BUG_ON(err == -EEXIST);
		goto out;
	}
	state = rb_entry(node, struct extent_state, rb_node);
C
Chris Mason 已提交
779
hit_next:
780 781 782 783 784 785 786 787 788 789
	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) {
C
Chris Mason 已提交
790
		struct rb_node *next_node;
791
		if (state->state & exclusive_bits) {
792 793 794 795
			*failed_start = state->start;
			err = -EEXIST;
			goto out;
		}
796

J
Josef Bacik 已提交
797 798 799 800
		err = set_state_bits(tree, state, bits);
		if (err)
			goto out;

801
		cache_state(state, cached_state);
802
		merge_state(tree, state);
803 804
		if (last_end == (u64)-1)
			goto out;
C
Chris Mason 已提交
805

806
		start = last_end + 1;
C
Chris Mason 已提交
807 808 809 810 811 812 813 814 815
		if (start < end && prealloc && !need_resched()) {
			next_node = rb_next(node);
			if (next_node) {
				state = rb_entry(next_node, struct extent_state,
						 rb_node);
				if (state->start == start)
					goto hit_next;
			}
		}
816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835
		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) {
836
		if (state->state & exclusive_bits) {
837 838 839 840 841 842 843 844 845 846
			*failed_start = start;
			err = -EEXIST;
			goto out;
		}
		err = split_state(tree, state, prealloc, start);
		BUG_ON(err == -EEXIST);
		prealloc = NULL;
		if (err)
			goto out;
		if (state->end <= end) {
J
Josef Bacik 已提交
847 848 849
			err = set_state_bits(tree, state, bits);
			if (err)
				goto out;
850
			cache_state(state, cached_state);
851
			merge_state(tree, state);
852 853 854
			if (last_end == (u64)-1)
				goto out;
			start = last_end + 1;
855 856 857 858 859 860 861 862 863 864 865 866 867 868 869
		}
		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
870
			this_end = last_start - 1;
871 872 873
		err = insert_state(tree, prealloc, start, this_end,
				   bits);
		BUG_ON(err == -EEXIST);
J
Josef Bacik 已提交
874 875
		if (err) {
			prealloc = NULL;
876
			goto out;
J
Josef Bacik 已提交
877 878 879
		}
		cache_state(prealloc, cached_state);
		prealloc = NULL;
880 881 882 883 884 885 886 887 888 889
		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) {
890
		if (state->state & exclusive_bits) {
891 892 893 894 895 896 897
			*failed_start = start;
			err = -EEXIST;
			goto out;
		}
		err = split_state(tree, state, prealloc, end + 1);
		BUG_ON(err == -EEXIST);

J
Josef Bacik 已提交
898 899 900 901 902
		err = set_state_bits(tree, prealloc, bits);
		if (err) {
			prealloc = NULL;
			goto out;
		}
903
		cache_state(prealloc, cached_state);
904 905 906 907 908 909 910 911
		merge_state(tree, prealloc);
		prealloc = NULL;
		goto out;
	}

	goto search_again;

out:
912
	spin_unlock(&tree->lock);
913 914 915 916 917 918 919 920
	if (prealloc)
		free_extent_state(prealloc);

	return err;

search_again:
	if (start > end)
		goto out;
921
	spin_unlock(&tree->lock);
922 923 924 925 926 927 928 929 930 931
	if (mask & __GFP_WAIT)
		cond_resched();
	goto again;
}

/* wrappers around set/clear extent bit */
int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
		     gfp_t mask)
{
	return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL,
932
			      NULL, mask);
933 934 935 936 937 938
}

int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
		    int bits, gfp_t mask)
{
	return set_extent_bit(tree, start, end, bits, 0, NULL,
939
			      NULL, mask);
940 941 942 943 944
}

int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
		      int bits, gfp_t mask)
{
945
	return clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask);
946 947 948 949 950 951
}

int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
		     gfp_t mask)
{
	return set_extent_bit(tree, start, end,
C
Chris Mason 已提交
952
			      EXTENT_DELALLOC | EXTENT_DIRTY | EXTENT_UPTODATE,
953
			      0, NULL, NULL, mask);
954 955 956 957 958 959
}

int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
		       gfp_t mask)
{
	return clear_extent_bit(tree, start, end,
960 961
				EXTENT_DIRTY | EXTENT_DELALLOC |
				EXTENT_DO_ACCOUNTING, 0, 0,
962
				NULL, mask);
963 964 965 966 967 968
}

int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
		     gfp_t mask)
{
	return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL,
969
			      NULL, mask);
970 971
}

972
static int clear_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
973 974
		       gfp_t mask)
{
975 976
	return clear_extent_bit(tree, start, end, EXTENT_NEW, 0, 0,
				NULL, mask);
977 978 979 980 981 982
}

int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
			gfp_t mask)
{
	return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, NULL,
983
			      NULL, mask);
984 985
}

C
Chris Mason 已提交
986 987
static int clear_extent_uptodate(struct extent_io_tree *tree, u64 start,
				 u64 end, gfp_t mask)
988
{
989 990
	return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
				NULL, mask);
991 992 993 994 995 996 997
}

int wait_on_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end)
{
	return wait_extent_bit(tree, start, end, EXTENT_WRITEBACK);
}

C
Chris Mason 已提交
998 999 1000 1001
/*
 * either insert or lock state struct between start and end use mask to tell
 * us if waiting is desired.
 */
1002
int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1003
		     int bits, struct extent_state **cached_state, gfp_t mask)
1004 1005 1006 1007
{
	int err;
	u64 failed_start;
	while (1) {
1008
		err = set_extent_bit(tree, start, end, EXTENT_LOCKED | bits,
1009 1010
				     EXTENT_LOCKED, &failed_start,
				     cached_state, mask);
1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021
		if (err == -EEXIST && (mask & __GFP_WAIT)) {
			wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
			start = failed_start;
		} else {
			break;
		}
		WARN_ON(start > end);
	}
	return err;
}

1022 1023
int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
{
1024
	return lock_extent_bits(tree, start, end, 0, NULL, mask);
1025 1026
}

1027 1028 1029 1030 1031 1032
int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end,
		    gfp_t mask)
{
	int err;
	u64 failed_start;

1033 1034
	err = set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
			     &failed_start, NULL, mask);
Y
Yan Zheng 已提交
1035 1036 1037
	if (err == -EEXIST) {
		if (failed_start > start)
			clear_extent_bit(tree, start, failed_start - 1,
1038
					 EXTENT_LOCKED, 1, 0, NULL, mask);
1039
		return 0;
Y
Yan Zheng 已提交
1040
	}
1041 1042 1043
	return 1;
}

1044 1045 1046 1047 1048 1049 1050
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);
}

1051 1052 1053
int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end,
		  gfp_t mask)
{
1054 1055
	return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
				mask);
1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079
}

/*
 * helper function to set pages and extents in the tree dirty
 */
int set_range_dirty(struct extent_io_tree *tree, 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(tree->mapping, index);
		BUG_ON(!page);
		__set_page_dirty_nobuffers(page);
		page_cache_release(page);
		index++;
	}
	return 0;
}

/*
 * helper function to set both pages and extents in the tree writeback
 */
1080
static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095
{
	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);
		BUG_ON(!page);
		set_page_writeback(page);
		page_cache_release(page);
		index++;
	}
	return 0;
}

C
Chris Mason 已提交
1096 1097 1098 1099 1100 1101 1102
/*
 * 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.
 *
 * If nothing was found, 1 is returned, < 0 on error
 */
1103 1104 1105 1106 1107 1108 1109
int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
			  u64 *start_ret, u64 *end_ret, int bits)
{
	struct rb_node *node;
	struct extent_state *state;
	int ret = 1;

1110
	spin_lock(&tree->lock);
1111 1112 1113 1114
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1115
	node = tree_search(tree, start);
C
Chris Mason 已提交
1116
	if (!node)
1117 1118
		goto out;

C
Chris Mason 已提交
1119
	while (1) {
1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131
		state = rb_entry(node, struct extent_state, rb_node);
		if (state->end >= start && (state->state & bits)) {
			*start_ret = state->start;
			*end_ret = state->end;
			ret = 0;
			break;
		}
		node = rb_next(node);
		if (!node)
			break;
	}
out:
1132
	spin_unlock(&tree->lock);
1133 1134 1135
	return ret;
}

C
Chris Mason 已提交
1136 1137 1138 1139
/* 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'
 */
C
Chris Mason 已提交
1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150
struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree,
						 u64 start, int bits)
{
	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
1151
	if (!node)
C
Chris Mason 已提交
1152 1153
		goto out;

C
Chris Mason 已提交
1154
	while (1) {
C
Chris Mason 已提交
1155
		state = rb_entry(node, struct extent_state, rb_node);
C
Chris Mason 已提交
1156
		if (state->end >= start && (state->state & bits))
C
Chris Mason 已提交
1157
			return state;
C
Chris Mason 已提交
1158

C
Chris Mason 已提交
1159 1160 1161 1162 1163 1164 1165 1166
		node = rb_next(node);
		if (!node)
			break;
	}
out:
	return NULL;
}

C
Chris Mason 已提交
1167 1168 1169 1170 1171 1172
/*
 * 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
1173 1174
static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
					u64 *start, u64 *end, u64 max_bytes)
1175 1176 1177 1178 1179 1180 1181
{
	struct rb_node *node;
	struct extent_state *state;
	u64 cur_start = *start;
	u64 found = 0;
	u64 total_bytes = 0;

1182
	spin_lock(&tree->lock);
C
Chris Mason 已提交
1183

1184 1185 1186 1187
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1188
	node = tree_search(tree, cur_start);
1189
	if (!node) {
1190 1191
		if (!found)
			*end = (u64)-1;
1192 1193 1194
		goto out;
	}

C
Chris Mason 已提交
1195
	while (1) {
1196
		state = rb_entry(node, struct extent_state, rb_node);
1197 1198
		if (found && (state->start != cur_start ||
			      (state->state & EXTENT_BOUNDARY))) {
1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218
			goto out;
		}
		if (!(state->state & EXTENT_DELALLOC)) {
			if (!found)
				*end = state->end;
			goto out;
		}
		if (!found)
			*start = state->start;
		found++;
		*end = state->end;
		cur_start = state->end + 1;
		node = rb_next(node);
		if (!node)
			break;
		total_bytes += state->end - state->start + 1;
		if (total_bytes >= max_bytes)
			break;
	}
out:
1219
	spin_unlock(&tree->lock);
1220 1221 1222
	return found;
}

C
Chris Mason 已提交
1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236
static noinline int __unlock_for_delalloc(struct inode *inode,
					  struct page *locked_page,
					  u64 start, u64 end)
{
	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)
		return 0;

C
Chris Mason 已提交
1237
	while (nr_pages > 0) {
C
Chris Mason 已提交
1238
		ret = find_get_pages_contig(inode->i_mapping, index,
1239 1240
				     min_t(unsigned long, nr_pages,
				     ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272
		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();
	}
	return 0;
}

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
1273
	while (nrpages > 0) {
C
Chris Mason 已提交
1274
		ret = find_get_pages_contig(inode->i_mapping, index,
1275 1276
				     min_t(unsigned long,
				     nrpages, ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1277 1278 1279 1280 1281 1282 1283 1284 1285 1286
		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
			 */
1287
			if (pages[i] != locked_page) {
C
Chris Mason 已提交
1288
				lock_page(pages[i]);
1289 1290
				if (!PageDirty(pages[i]) ||
				    pages[i]->mapping != inode->i_mapping) {
1291 1292 1293 1294 1295 1296
					ret = -EAGAIN;
					unlock_page(pages[i]);
					page_cache_release(pages[i]);
					goto done;
				}
			}
C
Chris Mason 已提交
1297
			page_cache_release(pages[i]);
1298
			pages_locked++;
C
Chris Mason 已提交
1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329
		}
		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
 */
static noinline u64 find_lock_delalloc_range(struct inode *inode,
					     struct extent_io_tree *tree,
					     struct page *locked_page,
					     u64 *start, u64 *end,
					     u64 max_bytes)
{
	u64 delalloc_start;
	u64 delalloc_end;
	u64 found;
1330
	struct extent_state *cached_state = NULL;
C
Chris Mason 已提交
1331 1332 1333 1334 1335 1336 1337 1338 1339
	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,
				    max_bytes);
C
Chris Mason 已提交
1340
	if (!found || delalloc_end <= *start) {
C
Chris Mason 已提交
1341 1342 1343 1344 1345
		*start = delalloc_start;
		*end = delalloc_end;
		return found;
	}

C
Chris Mason 已提交
1346 1347 1348 1349 1350
	/*
	 * 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
1351
	if (delalloc_start < *start)
C
Chris Mason 已提交
1352 1353
		delalloc_start = *start;

C
Chris Mason 已提交
1354 1355 1356 1357
	/*
	 * make sure to limit the number of pages we try to lock down
	 * if we're looping.
	 */
C
Chris Mason 已提交
1358
	if (delalloc_end + 1 - delalloc_start > max_bytes && loops)
1359
		delalloc_end = delalloc_start + PAGE_CACHE_SIZE - 1;
C
Chris Mason 已提交
1360

C
Chris Mason 已提交
1361 1362 1363 1364 1365 1366 1367
	/* 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
		 */
1368
		free_extent_state(cached_state);
C
Chris Mason 已提交
1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381
		if (!loops) {
			unsigned long offset = (*start) & (PAGE_CACHE_SIZE - 1);
			max_bytes = PAGE_CACHE_SIZE - offset;
			loops = 1;
			goto again;
		} else {
			found = 0;
			goto out_failed;
		}
	}
	BUG_ON(ret);

	/* step three, lock the state bits for the whole range */
1382 1383
	lock_extent_bits(tree, delalloc_start, delalloc_end,
			 0, &cached_state, GFP_NOFS);
C
Chris Mason 已提交
1384 1385 1386

	/* then test to make sure it is all still delalloc */
	ret = test_range_bit(tree, delalloc_start, delalloc_end,
1387
			     EXTENT_DELALLOC, 1, cached_state);
C
Chris Mason 已提交
1388
	if (!ret) {
1389 1390
		unlock_extent_cached(tree, delalloc_start, delalloc_end,
				     &cached_state, GFP_NOFS);
C
Chris Mason 已提交
1391 1392 1393 1394 1395
		__unlock_for_delalloc(inode, locked_page,
			      delalloc_start, delalloc_end);
		cond_resched();
		goto again;
	}
1396
	free_extent_state(cached_state);
C
Chris Mason 已提交
1397 1398 1399 1400 1401 1402 1403 1404 1405
	*start = delalloc_start;
	*end = delalloc_end;
out_failed:
	return found;
}

int extent_clear_unlock_delalloc(struct inode *inode,
				struct extent_io_tree *tree,
				u64 start, u64 end, struct page *locked_page,
1406
				unsigned long op)
C
Chris Mason 已提交
1407 1408 1409 1410 1411 1412 1413
{
	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;
1414
	int clear_bits = 0;
C
Chris Mason 已提交
1415

1416
	if (op & EXTENT_CLEAR_UNLOCK)
1417
		clear_bits |= EXTENT_LOCKED;
1418
	if (op & EXTENT_CLEAR_DIRTY)
C
Chris Mason 已提交
1419 1420
		clear_bits |= EXTENT_DIRTY;

1421
	if (op & EXTENT_CLEAR_DELALLOC)
1422 1423
		clear_bits |= EXTENT_DELALLOC;

1424 1425 1426
	if (op & EXTENT_CLEAR_ACCOUNTING)
		clear_bits |= EXTENT_DO_ACCOUNTING;

1427
	clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1428 1429 1430
	if (!(op & (EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
		    EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK |
		    EXTENT_SET_PRIVATE2)))
1431
		return 0;
C
Chris Mason 已提交
1432

C
Chris Mason 已提交
1433
	while (nr_pages > 0) {
C
Chris Mason 已提交
1434
		ret = find_get_pages_contig(inode->i_mapping, index,
1435 1436
				     min_t(unsigned long,
				     nr_pages, ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1437
		for (i = 0; i < ret; i++) {
1438

1439
			if (op & EXTENT_SET_PRIVATE2)
1440 1441
				SetPagePrivate2(pages[i]);

C
Chris Mason 已提交
1442 1443 1444 1445
			if (pages[i] == locked_page) {
				page_cache_release(pages[i]);
				continue;
			}
1446
			if (op & EXTENT_CLEAR_DIRTY)
C
Chris Mason 已提交
1447
				clear_page_dirty_for_io(pages[i]);
1448
			if (op & EXTENT_SET_WRITEBACK)
C
Chris Mason 已提交
1449
				set_page_writeback(pages[i]);
1450
			if (op & EXTENT_END_WRITEBACK)
C
Chris Mason 已提交
1451
				end_page_writeback(pages[i]);
1452
			if (op & EXTENT_CLEAR_UNLOCK_PAGE)
1453
				unlock_page(pages[i]);
C
Chris Mason 已提交
1454 1455 1456 1457 1458 1459 1460 1461 1462
			page_cache_release(pages[i]);
		}
		nr_pages -= ret;
		index += ret;
		cond_resched();
	}
	return 0;
}

C
Chris Mason 已提交
1463 1464 1465 1466 1467
/*
 * 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.
 */
1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482
u64 count_range_bits(struct extent_io_tree *tree,
		     u64 *start, u64 search_end, u64 max_bytes,
		     unsigned long bits)
{
	struct rb_node *node;
	struct extent_state *state;
	u64 cur_start = *start;
	u64 total_bytes = 0;
	int found = 0;

	if (search_end <= cur_start) {
		WARN_ON(1);
		return 0;
	}

1483
	spin_lock(&tree->lock);
1484 1485 1486 1487 1488 1489 1490 1491
	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.
	 */
1492
	node = tree_search(tree, cur_start);
C
Chris Mason 已提交
1493
	if (!node)
1494 1495
		goto out;

C
Chris Mason 已提交
1496
	while (1) {
1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514
		state = rb_entry(node, struct extent_state, rb_node);
		if (state->start > search_end)
			break;
		if (state->end >= cur_start && (state->state & bits)) {
			total_bytes += min(search_end, state->end) + 1 -
				       max(cur_start, state->start);
			if (total_bytes >= max_bytes)
				break;
			if (!found) {
				*start = state->start;
				found = 1;
			}
		}
		node = rb_next(node);
		if (!node)
			break;
	}
out:
1515
	spin_unlock(&tree->lock);
1516 1517
	return total_bytes;
}
1518

C
Chris Mason 已提交
1519 1520 1521 1522
/*
 * set the private field for a given byte offset in the tree.  If there isn't
 * an extent_state there already, this does nothing.
 */
1523 1524 1525 1526 1527 1528
int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
{
	struct rb_node *node;
	struct extent_state *state;
	int ret = 0;

1529
	spin_lock(&tree->lock);
1530 1531 1532 1533
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1534
	node = tree_search(tree, start);
1535
	if (!node) {
1536 1537 1538 1539 1540 1541 1542 1543 1544 1545
		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:
1546
	spin_unlock(&tree->lock);
1547 1548 1549 1550 1551 1552 1553 1554 1555
	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;

1556
	spin_lock(&tree->lock);
1557 1558 1559 1560
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1561
	node = tree_search(tree, start);
1562
	if (!node) {
1563 1564 1565 1566 1567 1568 1569 1570 1571 1572
		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:
1573
	spin_unlock(&tree->lock);
1574 1575 1576 1577 1578
	return ret;
}

/*
 * searches a range in the state tree for a given mask.
1579
 * If 'filled' == 1, this returns 1 only if every extent in the tree
1580 1581 1582 1583
 * 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,
1584
		   int bits, int filled, struct extent_state *cached)
1585 1586 1587 1588 1589
{
	struct extent_state *state = NULL;
	struct rb_node *node;
	int bitset = 0;

1590
	spin_lock(&tree->lock);
1591 1592 1593 1594
	if (cached && cached->tree && cached->start == start)
		node = &cached->rb_node;
	else
		node = tree_search(tree, start);
1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613
	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;
		}
1614 1615 1616 1617

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

1618 1619 1620 1621 1622 1623 1624 1625 1626 1627
		start = state->end + 1;
		if (start > end)
			break;
		node = rb_next(node);
		if (!node) {
			if (filled)
				bitset = 0;
			break;
		}
	}
1628
	spin_unlock(&tree->lock);
1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640
	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
 */
static int check_page_uptodate(struct extent_io_tree *tree,
			       struct page *page)
{
	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
	u64 end = start + PAGE_CACHE_SIZE - 1;
1641
	if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654
		SetPageUptodate(page);
	return 0;
}

/*
 * helper function to unlock a page if all the extents in the tree
 * for that page are unlocked
 */
static int check_page_locked(struct extent_io_tree *tree,
			     struct page *page)
{
	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
	u64 end = start + PAGE_CACHE_SIZE - 1;
1655
	if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL))
1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666
		unlock_page(page);
	return 0;
}

/*
 * helper function to end page writeback if all the extents
 * in the tree for that page are done with writeback
 */
static int check_page_writeback(struct extent_io_tree *tree,
			     struct page *page)
{
1667
	end_page_writeback(page);
1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683
	return 0;
}

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

/*
 * 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)
{
1684
	int uptodate = err == 0;
1685
	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1686
	struct extent_io_tree *tree;
1687 1688 1689
	u64 start;
	u64 end;
	int whole_page;
1690
	int ret;
1691 1692 1693

	do {
		struct page *page = bvec->bv_page;
1694 1695
		tree = &BTRFS_I(page->mapping->host)->io_tree;

1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706
		start = ((u64)page->index << PAGE_CACHE_SHIFT) +
			 bvec->bv_offset;
		end = start + bvec->bv_len - 1;

		if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
			whole_page = 1;
		else
			whole_page = 0;

		if (--bvec >= bio->bi_io_vec)
			prefetchw(&bvec->bv_page->flags);
1707 1708
		if (tree->ops && tree->ops->writepage_end_io_hook) {
			ret = tree->ops->writepage_end_io_hook(page, start,
1709
						       end, NULL, uptodate);
1710 1711 1712 1713 1714 1715 1716
			if (ret)
				uptodate = 0;
		}

		if (!uptodate && tree->ops &&
		    tree->ops->writepage_io_failed_hook) {
			ret = tree->ops->writepage_io_failed_hook(bio, page,
1717
							 start, end, NULL);
1718 1719 1720 1721 1722 1723
			if (ret == 0) {
				uptodate = (err == 0);
				continue;
			}
		}

1724
		if (!uptodate) {
1725
			clear_extent_uptodate(tree, start, end, GFP_NOFS);
1726 1727 1728
			ClearPageUptodate(page);
			SetPageError(page);
		}
1729

1730 1731 1732 1733 1734
		if (whole_page)
			end_page_writeback(page);
		else
			check_page_writeback(tree, page);
	} while (bvec >= bio->bi_io_vec);
1735

1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753
	bio_put(bio);
}

/*
 * 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)
{
	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1754
	struct extent_io_tree *tree;
1755 1756 1757 1758 1759
	u64 start;
	u64 end;
	int whole_page;
	int ret;

1760 1761 1762
	if (err)
		uptodate = 0;

1763 1764
	do {
		struct page *page = bvec->bv_page;
1765 1766
		tree = &BTRFS_I(page->mapping->host)->io_tree;

1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779
		start = ((u64)page->index << PAGE_CACHE_SHIFT) +
			bvec->bv_offset;
		end = start + bvec->bv_len - 1;

		if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE)
			whole_page = 1;
		else
			whole_page = 0;

		if (--bvec >= bio->bi_io_vec)
			prefetchw(&bvec->bv_page->flags);

		if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
1780
			ret = tree->ops->readpage_end_io_hook(page, start, end,
1781
							      NULL);
1782 1783 1784
			if (ret)
				uptodate = 0;
		}
1785 1786 1787
		if (!uptodate && tree->ops &&
		    tree->ops->readpage_io_failed_hook) {
			ret = tree->ops->readpage_io_failed_hook(bio, page,
1788
							 start, end, NULL);
1789
			if (ret == 0) {
1790 1791
				uptodate =
					test_bit(BIO_UPTODATE, &bio->bi_flags);
1792 1793
				if (err)
					uptodate = 0;
1794 1795 1796
				continue;
			}
		}
1797

1798
		if (uptodate) {
1799 1800
			set_extent_uptodate(tree, start, end,
					    GFP_ATOMIC);
1801
		}
1802
		unlock_extent(tree, start, end, GFP_ATOMIC);
1803

1804 1805 1806 1807 1808 1809 1810
		if (whole_page) {
			if (uptodate) {
				SetPageUptodate(page);
			} else {
				ClearPageUptodate(page);
				SetPageError(page);
			}
1811
			unlock_page(page);
1812 1813 1814 1815 1816 1817 1818
		} else {
			if (uptodate) {
				check_page_uptodate(tree, page);
			} else {
				ClearPageUptodate(page);
				SetPageError(page);
			}
1819
			check_page_locked(tree, page);
1820
		}
1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834
	} while (bvec >= bio->bi_io_vec);

	bio_put(bio);
}

/*
 * IO done from prepare_write is pretty simple, we just unlock
 * the structs in the extent tree when done, and set the uptodate bits
 * as appropriate.
 */
static void end_bio_extent_preparewrite(struct bio *bio, int err)
{
	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1835
	struct extent_io_tree *tree;
1836 1837 1838 1839 1840
	u64 start;
	u64 end;

	do {
		struct page *page = bvec->bv_page;
1841 1842
		tree = &BTRFS_I(page->mapping->host)->io_tree;

1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877
		start = ((u64)page->index << PAGE_CACHE_SHIFT) +
			bvec->bv_offset;
		end = start + bvec->bv_len - 1;

		if (--bvec >= bio->bi_io_vec)
			prefetchw(&bvec->bv_page->flags);

		if (uptodate) {
			set_extent_uptodate(tree, start, end, GFP_ATOMIC);
		} else {
			ClearPageUptodate(page);
			SetPageError(page);
		}

		unlock_extent(tree, start, end, GFP_ATOMIC);

	} while (bvec >= bio->bi_io_vec);

	bio_put(bio);
}

static struct bio *
extent_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
		 gfp_t gfp_flags)
{
	struct bio *bio;

	bio = bio_alloc(gfp_flags, nr_vecs);

	if (bio == NULL && (current->flags & PF_MEMALLOC)) {
		while (!bio && (nr_vecs /= 2))
			bio = bio_alloc(gfp_flags, nr_vecs);
	}

	if (bio) {
1878
		bio->bi_size = 0;
1879 1880 1881 1882 1883 1884
		bio->bi_bdev = bdev;
		bio->bi_sector = first_sector;
	}
	return bio;
}

C
Chris Mason 已提交
1885 1886
static int submit_one_bio(int rw, struct bio *bio, int mirror_num,
			  unsigned long bio_flags)
1887 1888
{
	int ret = 0;
1889 1890 1891 1892 1893 1894 1895 1896 1897
	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;
	u64 end;

	start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset;
	end = start + bvec->bv_len - 1;

1898
	bio->bi_private = NULL;
1899 1900 1901

	bio_get(bio);

1902
	if (tree->ops && tree->ops->submit_bio_hook)
1903
		tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
C
Chris Mason 已提交
1904
					   mirror_num, bio_flags);
1905 1906
	else
		submit_bio(rw, bio);
1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918
	if (bio_flagged(bio, BIO_EOPNOTSUPP))
		ret = -EOPNOTSUPP;
	bio_put(bio);
	return ret;
}

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,
1919
			      bio_end_io_t end_io_func,
C
Chris Mason 已提交
1920 1921 1922
			      int mirror_num,
			      unsigned long prev_bio_flags,
			      unsigned long bio_flags)
1923 1924 1925 1926
{
	int ret = 0;
	struct bio *bio;
	int nr;
C
Chris Mason 已提交
1927 1928 1929
	int contig = 0;
	int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
	int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
1930
	size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
1931 1932 1933

	if (bio_ret && *bio_ret) {
		bio = *bio_ret;
C
Chris Mason 已提交
1934 1935 1936 1937 1938 1939 1940
		if (old_compressed)
			contig = bio->bi_sector == sector;
		else
			contig = bio->bi_sector + (bio->bi_size >> 9) ==
				sector;

		if (prev_bio_flags != bio_flags || !contig ||
1941
		    (tree->ops && tree->ops->merge_bio_hook &&
C
Chris Mason 已提交
1942 1943 1944 1945 1946
		     tree->ops->merge_bio_hook(page, offset, page_size, bio,
					       bio_flags)) ||
		    bio_add_page(bio, page, page_size, offset) < page_size) {
			ret = submit_one_bio(rw, bio, mirror_num,
					     prev_bio_flags);
1947 1948 1949 1950 1951
			bio = NULL;
		} else {
			return 0;
		}
	}
C
Chris Mason 已提交
1952 1953 1954 1955 1956
	if (this_compressed)
		nr = BIO_MAX_PAGES;
	else
		nr = bio_get_nr_vecs(bdev);

1957
	bio = extent_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
1958

C
Chris Mason 已提交
1959
	bio_add_page(bio, page, page_size, offset);
1960 1961
	bio->bi_end_io = end_io_func;
	bio->bi_private = tree;
1962

C
Chris Mason 已提交
1963
	if (bio_ret)
1964
		*bio_ret = bio;
C
Chris Mason 已提交
1965
	else
C
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1966
		ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
1967 1968 1969 1970 1971 1972 1973 1974 1975

	return ret;
}

void set_page_extent_mapped(struct page *page)
{
	if (!PagePrivate(page)) {
		SetPagePrivate(page);
		page_cache_get(page);
1976
		set_page_private(page, EXTENT_PAGE_PRIVATE);
1977 1978 1979
	}
}

1980
static void set_page_extent_head(struct page *page, unsigned long len)
1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992
{
	set_page_private(page, EXTENT_PAGE_PRIVATE_FIRST_PAGE | len << 2);
}

/*
 * 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)
 */
static int __extent_read_full_page(struct extent_io_tree *tree,
				   struct page *page,
				   get_extent_t *get_extent,
C
Chris Mason 已提交
1993 1994
				   struct bio **bio, int mirror_num,
				   unsigned long *bio_flags)
1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
{
	struct inode *inode = page->mapping->host;
	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
	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;
	size_t page_offset = 0;
	size_t iosize;
C
Chris Mason 已提交
2012
	size_t disk_io_size;
2013
	size_t blocksize = inode->i_sb->s_blocksize;
C
Chris Mason 已提交
2014
	unsigned long this_bio_flag = 0;
2015 2016 2017 2018 2019 2020

	set_page_extent_mapped(page);

	end = page_end;
	lock_extent(tree, start, end, GFP_NOFS);

C
Chris Mason 已提交
2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032
	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;
			userpage = kmap_atomic(page, KM_USER0);
			memset(userpage + zero_offset, 0, iosize);
			flush_dcache_page(page);
			kunmap_atomic(userpage, KM_USER0);
		}
	}
2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056
	while (cur <= end) {
		if (cur >= last_byte) {
			char *userpage;
			iosize = PAGE_CACHE_SIZE - page_offset;
			userpage = kmap_atomic(page, KM_USER0);
			memset(userpage + page_offset, 0, iosize);
			flush_dcache_page(page);
			kunmap_atomic(userpage, KM_USER0);
			set_extent_uptodate(tree, cur, cur + iosize - 1,
					    GFP_NOFS);
			unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
			break;
		}
		em = get_extent(inode, page, page_offset, cur,
				end - cur + 1, 0);
		if (IS_ERR(em) || !em) {
			SetPageError(page);
			unlock_extent(tree, cur, end, GFP_NOFS);
			break;
		}
		extent_offset = cur - em->start;
		BUG_ON(extent_map_end(em) <= cur);
		BUG_ON(end < cur);

C
Chris Mason 已提交
2057 2058 2059
		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
			this_bio_flag = EXTENT_BIO_COMPRESSED;

2060 2061 2062
		iosize = min(extent_map_end(em) - cur, end - cur + 1);
		cur_end = min(extent_map_end(em) - 1, end);
		iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
C
Chris Mason 已提交
2063 2064 2065 2066 2067 2068 2069
		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;
		}
2070 2071
		bdev = em->bdev;
		block_start = em->block_start;
Y
Yan Zheng 已提交
2072 2073
		if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
			block_start = EXTENT_MAP_HOLE;
2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092
		free_extent_map(em);
		em = NULL;

		/* we've found a hole, just zero and go on */
		if (block_start == EXTENT_MAP_HOLE) {
			char *userpage;
			userpage = kmap_atomic(page, KM_USER0);
			memset(userpage + page_offset, 0, iosize);
			flush_dcache_page(page);
			kunmap_atomic(userpage, KM_USER0);

			set_extent_uptodate(tree, cur, cur + iosize - 1,
					    GFP_NOFS);
			unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
			cur = cur + iosize;
			page_offset += iosize;
			continue;
		}
		/* the get_extent function already copied into the page */
2093 2094
		if (test_range_bit(tree, cur, cur_end,
				   EXTENT_UPTODATE, 1, NULL)) {
2095
			check_page_uptodate(tree, page);
2096 2097 2098 2099 2100
			unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
			cur = cur + iosize;
			page_offset += iosize;
			continue;
		}
2101 2102 2103 2104 2105 2106 2107 2108 2109 2110
		/* we have an inline extent but it didn't get marked up
		 * to date.  Error out
		 */
		if (block_start == EXTENT_MAP_INLINE) {
			SetPageError(page);
			unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
			cur = cur + iosize;
			page_offset += iosize;
			continue;
		}
2111 2112 2113 2114 2115 2116 2117

		ret = 0;
		if (tree->ops && tree->ops->readpage_io_hook) {
			ret = tree->ops->readpage_io_hook(page, cur,
							  cur + iosize - 1);
		}
		if (!ret) {
2118 2119
			unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;
			pnr -= page->index;
2120
			ret = submit_extent_page(READ, tree, page,
C
Chris Mason 已提交
2121
					 sector, disk_io_size, page_offset,
2122
					 bdev, bio, pnr,
C
Chris Mason 已提交
2123 2124 2125
					 end_bio_extent_readpage, mirror_num,
					 *bio_flags,
					 this_bio_flag);
2126
			nr++;
C
Chris Mason 已提交
2127
			*bio_flags = this_bio_flag;
2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145
		}
		if (ret)
			SetPageError(page);
		cur = cur + iosize;
		page_offset += iosize;
	}
	if (!nr) {
		if (!PageError(page))
			SetPageUptodate(page);
		unlock_page(page);
	}
	return 0;
}

int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
			    get_extent_t *get_extent)
{
	struct bio *bio = NULL;
C
Chris Mason 已提交
2146
	unsigned long bio_flags = 0;
2147 2148
	int ret;

C
Chris Mason 已提交
2149 2150
	ret = __extent_read_full_page(tree, page, get_extent, &bio, 0,
				      &bio_flags);
2151
	if (bio)
C
Chris Mason 已提交
2152
		submit_one_bio(READ, bio, 0, bio_flags);
2153 2154 2155
	return ret;
}

2156 2157 2158 2159 2160 2161 2162 2163 2164 2165
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;
}

2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186
/*
 * 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;
	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
	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;
2187
	u64 unlock_start;
2188
	sector_t sector;
2189
	struct extent_state *cached_state = NULL;
2190 2191 2192 2193
	struct extent_map *em;
	struct block_device *bdev;
	int ret;
	int nr = 0;
2194
	size_t pg_offset = 0;
2195 2196 2197 2198 2199
	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
2200 2201
	int page_started;
	int compressed;
2202
	int write_flags;
2203
	unsigned long nr_written = 0;
2204

2205 2206 2207 2208 2209
	if (wbc->sync_mode == WB_SYNC_ALL)
		write_flags = WRITE_SYNC_PLUG;
	else
		write_flags = WRITE;

2210
	WARN_ON(!PageLocked(page));
2211
	pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
2212
	if (page->index > end_index ||
2213
	   (page->index == end_index && !pg_offset)) {
2214
		page->mapping->a_ops->invalidatepage(page, 0);
2215 2216 2217 2218 2219 2220 2221 2222
		unlock_page(page);
		return 0;
	}

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

		userpage = kmap_atomic(page, KM_USER0);
2223 2224
		memset(userpage + pg_offset, 0,
		       PAGE_CACHE_SIZE - pg_offset);
2225
		kunmap_atomic(userpage, KM_USER0);
2226
		flush_dcache_page(page);
2227
	}
2228
	pg_offset = 0;
2229 2230 2231 2232 2233

	set_page_extent_mapped(page);

	delalloc_start = start;
	delalloc_end = 0;
C
Chris Mason 已提交
2234
	page_started = 0;
2235
	if (!epd->extent_locked) {
2236
		u64 delalloc_to_write = 0;
2237 2238 2239 2240 2241 2242
		/*
		 * 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
2243
		while (delalloc_end < page_end) {
2244
			nr_delalloc = find_lock_delalloc_range(inode, tree,
C
Chris Mason 已提交
2245 2246
						       page,
						       &delalloc_start,
2247 2248
						       &delalloc_end,
						       128 * 1024 * 1024);
2249 2250 2251 2252 2253 2254 2255
			if (nr_delalloc == 0) {
				delalloc_start = delalloc_end + 1;
				continue;
			}
			tree->ops->fill_delalloc(inode, page, delalloc_start,
						 delalloc_end, &page_started,
						 &nr_written);
2256 2257 2258 2259 2260 2261 2262 2263
			/*
			 * 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;
2264 2265
			delalloc_start = delalloc_end + 1;
		}
2266 2267 2268 2269 2270 2271 2272 2273
		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
2274

2275 2276 2277 2278 2279
		/* did the fill delalloc function already unlock and start
		 * the IO?
		 */
		if (page_started) {
			ret = 0;
2280 2281 2282 2283 2284 2285 2286
			/*
			 * 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;
2287
		}
C
Chris Mason 已提交
2288
	}
2289
	if (tree->ops && tree->ops->writepage_start_hook) {
C
Chris Mason 已提交
2290 2291
		ret = tree->ops->writepage_start_hook(page, start,
						      page_end);
2292 2293
		if (ret == -EAGAIN) {
			redirty_page_for_writepage(wbc, page);
2294
			update_nr_written(page, wbc, nr_written);
2295
			unlock_page(page);
2296
			ret = 0;
2297
			goto done_unlocked;
2298 2299 2300
		}
	}

2301 2302 2303 2304 2305
	/*
	 * 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);
2306

2307 2308
	end = page_end;
	if (last_byte <= start) {
2309 2310 2311 2312
		if (tree->ops && tree->ops->writepage_end_io_hook)
			tree->ops->writepage_end_io_hook(page, start,
							 page_end, NULL, 1);
		unlock_start = page_end + 1;
2313 2314 2315 2316 2317 2318 2319
		goto done;
	}

	blocksize = inode->i_sb->s_blocksize;

	while (cur <= end) {
		if (cur >= last_byte) {
2320 2321 2322 2323
			if (tree->ops && tree->ops->writepage_end_io_hook)
				tree->ops->writepage_end_io_hook(page, cur,
							 page_end, NULL, 1);
			unlock_start = page_end + 1;
2324 2325
			break;
		}
2326
		em = epd->get_extent(inode, page, pg_offset, cur,
2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340
				     end - cur + 1, 1);
		if (IS_ERR(em) || !em) {
			SetPageError(page);
			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);
		iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1);
		sector = (em->block_start + extent_offset) >> 9;
		bdev = em->bdev;
		block_start = em->block_start;
C
Chris Mason 已提交
2341
		compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
2342 2343 2344
		free_extent_map(em);
		em = NULL;

C
Chris Mason 已提交
2345 2346 2347 2348 2349
		/*
		 * compressed and inline extents are written through other
		 * paths in the FS
		 */
		if (compressed || block_start == EXTENT_MAP_HOLE ||
2350
		    block_start == EXTENT_MAP_INLINE) {
C
Chris Mason 已提交
2351 2352 2353 2354 2355 2356
			/*
			 * end_io notification does not happen here for
			 * compressed extents
			 */
			if (!compressed && tree->ops &&
			    tree->ops->writepage_end_io_hook)
2357 2358 2359
				tree->ops->writepage_end_io_hook(page, cur,
							 cur + iosize - 1,
							 NULL, 1);
C
Chris Mason 已提交
2360 2361 2362 2363 2364 2365 2366 2367 2368
			else if (compressed) {
				/* we don't want to end_page_writeback on
				 * a compressed extent.  this happens
				 * elsewhere
				 */
				nr++;
			}

			cur += iosize;
2369
			pg_offset += iosize;
2370
			unlock_start = cur;
2371 2372 2373 2374
			continue;
		}
		/* leave this out until we have a page_mkwrite call */
		if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
2375
				   EXTENT_DIRTY, 0, NULL)) {
2376
			cur = cur + iosize;
2377
			pg_offset += iosize;
2378 2379
			continue;
		}
C
Chris Mason 已提交
2380

2381 2382 2383 2384 2385 2386
		if (tree->ops && tree->ops->writepage_io_hook) {
			ret = tree->ops->writepage_io_hook(page, cur,
						cur + iosize - 1);
		} else {
			ret = 0;
		}
2387
		if (ret) {
2388
			SetPageError(page);
2389
		} else {
2390
			unsigned long max_nr = end_index + 1;
2391

2392 2393
			set_range_writeback(tree, cur, cur + iosize - 1);
			if (!PageWriteback(page)) {
C
Chris Mason 已提交
2394 2395 2396
				printk(KERN_ERR "btrfs warning page %lu not "
				       "writeback, cur %llu end %llu\n",
				       page->index, (unsigned long long)cur,
2397 2398 2399
				       (unsigned long long)end);
			}

2400 2401 2402
			ret = submit_extent_page(write_flags, tree, page,
						 sector, iosize, pg_offset,
						 bdev, &epd->bio, max_nr,
C
Chris Mason 已提交
2403 2404
						 end_bio_extent_writepage,
						 0, 0, 0);
2405 2406 2407 2408
			if (ret)
				SetPageError(page);
		}
		cur = cur + iosize;
2409
		pg_offset += iosize;
2410 2411 2412 2413 2414 2415 2416 2417 2418
		nr++;
	}
done:
	if (nr == 0) {
		/* make sure the mapping tag for page dirty gets cleared */
		set_page_writeback(page);
		end_page_writeback(page);
	}
	unlock_page(page);
2419

2420 2421
done_unlocked:

2422 2423
	/* drop our reference on any cached states */
	free_extent_state(cached_state);
2424 2425 2426 2427
	return 0;
}

/**
C
Chris Mason 已提交
2428
 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441
 * @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.
 */
2442
static int extent_write_cache_pages(struct extent_io_tree *tree,
C
Chris Mason 已提交
2443 2444
			     struct address_space *mapping,
			     struct writeback_control *wbc,
C
Chris Mason 已提交
2445 2446
			     writepage_t writepage, void *data,
			     void (*flush_fn)(void *))
2447 2448 2449
{
	int ret = 0;
	int done = 0;
2450
	int nr_to_write_done = 0;
2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469
	struct pagevec pvec;
	int nr_pages;
	pgoff_t index;
	pgoff_t end;		/* Inclusive */
	int scanned = 0;
	int range_whole = 0;

	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;
		if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
			range_whole = 1;
		scanned = 1;
	}
retry:
2470
	while (!done && !nr_to_write_done && (index <= end) &&
2471
	       (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
C
Chris Mason 已提交
2472 2473
			      PAGECACHE_TAG_DIRTY, min(end - index,
				  (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486
		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
			 */
C
Chris Mason 已提交
2487 2488 2489 2490
			if (tree->ops && tree->ops->write_cache_pages_lock_hook)
				tree->ops->write_cache_pages_lock_hook(page);
			else
				lock_page(page);
2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502

			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
2503
			if (wbc->sync_mode != WB_SYNC_NONE) {
2504 2505
				if (PageWriteback(page))
					flush_fn(data);
2506
				wait_on_page_writeback(page);
C
Chris Mason 已提交
2507
			}
2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520

			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;
			}
2521
			if (ret)
2522
				done = 1;
2523 2524 2525 2526 2527 2528 2529

			/*
			 * 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;
2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545
		}
		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;
	}
	return ret;
}

2546
static void flush_epd_write_bio(struct extent_page_data *epd)
C
Chris Mason 已提交
2547 2548
{
	if (epd->bio) {
2549 2550 2551 2552
		if (epd->sync_io)
			submit_one_bio(WRITE_SYNC, epd->bio, 0, 0);
		else
			submit_one_bio(WRITE, epd->bio, 0, 0);
C
Chris Mason 已提交
2553 2554 2555 2556
		epd->bio = NULL;
	}
}

2557 2558 2559 2560 2561 2562
static noinline void flush_write_bio(void *data)
{
	struct extent_page_data *epd = data;
	flush_epd_write_bio(epd);
}

2563 2564 2565 2566 2567 2568 2569 2570 2571 2572
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 address_space *mapping = page->mapping;
	struct extent_page_data epd = {
		.bio = NULL,
		.tree = tree,
		.get_extent = get_extent,
2573
		.extent_locked = 0,
2574
		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
2575 2576 2577
	};
	struct writeback_control wbc_writepages = {
		.bdi		= wbc->bdi,
2578
		.sync_mode	= wbc->sync_mode,
2579 2580 2581 2582 2583 2584 2585 2586
		.older_than_this = NULL,
		.nr_to_write	= 64,
		.range_start	= page_offset(page) + PAGE_CACHE_SIZE,
		.range_end	= (loff_t)-1,
	};

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

C
Chris Mason 已提交
2587
	extent_write_cache_pages(tree, mapping, &wbc_writepages,
C
Chris Mason 已提交
2588
				 __extent_writepage, &epd, flush_write_bio);
2589
	flush_epd_write_bio(&epd);
2590 2591 2592
	return ret;
}

2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607
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,
2608
		.sync_io = mode == WB_SYNC_ALL,
2609 2610 2611 2612 2613 2614 2615 2616 2617 2618
	};
	struct writeback_control wbc_writepages = {
		.bdi		= inode->i_mapping->backing_dev_info,
		.sync_mode	= mode,
		.older_than_this = NULL,
		.nr_to_write	= nr_pages * 2,
		.range_start	= start,
		.range_end	= end + 1,
	};

C
Chris Mason 已提交
2619
	while (start <= end) {
2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633
		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;
	}

2634
	flush_epd_write_bio(&epd);
2635 2636
	return ret;
}
2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647

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,
2648
		.extent_locked = 0,
2649
		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
2650 2651
	};

C
Chris Mason 已提交
2652
	ret = extent_write_cache_pages(tree, mapping, wbc,
C
Chris Mason 已提交
2653 2654
				       __extent_writepage, &epd,
				       flush_write_bio);
2655
	flush_epd_write_bio(&epd);
2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666
	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;
	struct pagevec pvec;
C
Chris Mason 已提交
2667
	unsigned long bio_flags = 0;
2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684

	pagevec_init(&pvec, 0);
	for (page_idx = 0; page_idx < nr_pages; page_idx++) {
		struct page *page = list_entry(pages->prev, struct page, lru);

		prefetchw(&page->flags);
		list_del(&page->lru);
		/*
		 * what we want to do here is call add_to_page_cache_lru,
		 * but that isn't exported, so we reproduce it here
		 */
		if (!add_to_page_cache(page, mapping,
					page->index, GFP_KERNEL)) {

			/* open coding of lru_cache_add, also not exported */
			page_cache_get(page);
			if (!pagevec_add(&pvec, page))
2685
				__pagevec_lru_add_file(&pvec);
2686
			__extent_read_full_page(tree, page, get_extent,
C
Chris Mason 已提交
2687
						&bio, 0, &bio_flags);
2688 2689 2690 2691
		}
		page_cache_release(page);
	}
	if (pagevec_count(&pvec))
2692
		__pagevec_lru_add_file(&pvec);
2693 2694
	BUG_ON(!list_empty(pages));
	if (bio)
C
Chris Mason 已提交
2695
		submit_one_bio(READ, bio, 0, bio_flags);
2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710
	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)
{
	u64 start = ((u64)page->index << PAGE_CACHE_SHIFT);
	u64 end = start + PAGE_CACHE_SIZE - 1;
	size_t blocksize = page->mapping->host->i_sb->s_blocksize;

C
Chris Mason 已提交
2711
	start += (offset + blocksize - 1) & ~(blocksize - 1);
2712 2713 2714 2715
	if (start > end)
		return 0;

	lock_extent(tree, start, end, GFP_NOFS);
2716
	wait_on_page_writeback(page);
2717
	clear_extent_bit(tree, start, end,
2718 2719
			 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
			 EXTENT_DO_ACCOUNTING,
2720
			 1, 1, NULL, GFP_NOFS);
2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770
	return 0;
}

/*
 * simple commit_write call, set_range_dirty is used to mark both
 * the pages and the extent records as dirty
 */
int extent_commit_write(struct extent_io_tree *tree,
			struct inode *inode, struct page *page,
			unsigned from, unsigned to)
{
	loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;

	set_page_extent_mapped(page);
	set_page_dirty(page);

	if (pos > inode->i_size) {
		i_size_write(inode, pos);
		mark_inode_dirty(inode);
	}
	return 0;
}

int extent_prepare_write(struct extent_io_tree *tree,
			 struct inode *inode, struct page *page,
			 unsigned from, unsigned to, get_extent_t *get_extent)
{
	u64 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
	u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
	u64 block_start;
	u64 orig_block_start;
	u64 block_end;
	u64 cur_end;
	struct extent_map *em;
	unsigned blocksize = 1 << inode->i_blkbits;
	size_t page_offset = 0;
	size_t block_off_start;
	size_t block_off_end;
	int err = 0;
	int iocount = 0;
	int ret = 0;
	int isnew;

	set_page_extent_mapped(page);

	block_start = (page_start + from) & ~((u64)blocksize - 1);
	block_end = (page_start + to - 1) | (blocksize - 1);
	orig_block_start = block_start;

	lock_extent(tree, page_start, page_end, GFP_NOFS);
C
Chris Mason 已提交
2771
	while (block_start <= block_end) {
2772 2773
		em = get_extent(inode, page, page_offset, block_start,
				block_end - block_start + 1, 1);
C
Chris Mason 已提交
2774
		if (IS_ERR(em) || !em)
2775
			goto err;
C
Chris Mason 已提交
2776

2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799
		cur_end = min(block_end, extent_map_end(em) - 1);
		block_off_start = block_start & (PAGE_CACHE_SIZE - 1);
		block_off_end = block_off_start + blocksize;
		isnew = clear_extent_new(tree, block_start, cur_end, GFP_NOFS);

		if (!PageUptodate(page) && isnew &&
		    (block_off_end > to || block_off_start < from)) {
			void *kaddr;

			kaddr = kmap_atomic(page, KM_USER0);
			if (block_off_end > to)
				memset(kaddr + to, 0, block_off_end - to);
			if (block_off_start < from)
				memset(kaddr + block_off_start, 0,
				       from - block_off_start);
			flush_dcache_page(page);
			kunmap_atomic(kaddr, KM_USER0);
		}
		if ((em->block_start != EXTENT_MAP_HOLE &&
		     em->block_start != EXTENT_MAP_INLINE) &&
		    !isnew && !PageUptodate(page) &&
		    (block_off_end > to || block_off_start < from) &&
		    !test_range_bit(tree, block_start, cur_end,
2800
				    EXTENT_UPTODATE, 1, NULL)) {
2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813
			u64 sector;
			u64 extent_offset = block_start - em->start;
			size_t iosize;
			sector = (em->block_start + extent_offset) >> 9;
			iosize = (cur_end - block_start + blocksize) &
				~((u64)blocksize - 1);
			/*
			 * we've already got the extent locked, but we
			 * need to split the state such that our end_bio
			 * handler can clear the lock.
			 */
			set_extent_bit(tree, block_start,
				       block_start + iosize - 1,
2814
				       EXTENT_LOCKED, 0, NULL, NULL, GFP_NOFS);
2815 2816 2817
			ret = submit_extent_page(READ, tree, page,
					 sector, iosize, page_offset, em->bdev,
					 NULL, 1,
C
Chris Mason 已提交
2818 2819
					 end_bio_extent_preparewrite, 0,
					 0, 0);
2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840
			iocount++;
			block_start = block_start + iosize;
		} else {
			set_extent_uptodate(tree, block_start, cur_end,
					    GFP_NOFS);
			unlock_extent(tree, block_start, cur_end, GFP_NOFS);
			block_start = cur_end + 1;
		}
		page_offset = block_start & (PAGE_CACHE_SIZE - 1);
		free_extent_map(em);
	}
	if (iocount) {
		wait_extent_bit(tree, orig_block_start,
				block_end, EXTENT_LOCKED);
	}
	check_page_uptodate(tree, page);
err:
	/* FIXME, zero out newly allocated blocks on error */
	return err;
}

2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853
/*
 * 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.
 */
int try_release_extent_state(struct extent_map_tree *map,
			     struct extent_io_tree *tree, struct page *page,
			     gfp_t mask)
{
	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
	u64 end = start + PAGE_CACHE_SIZE - 1;
	int ret = 1;

2854
	if (test_range_bit(tree, start, end,
2855
			   EXTENT_IOBITS, 0, NULL))
2856 2857 2858 2859
		ret = 0;
	else {
		if ((mask & GFP_NOFS) == GFP_NOFS)
			mask = GFP_NOFS;
2860 2861 2862 2863 2864 2865 2866
		/*
		 * at this point we can safely clear everything except the
		 * locked bit and the nodatasum bit
		 */
		clear_extent_bit(tree, start, end,
				 ~(EXTENT_LOCKED | EXTENT_NODATASUM),
				 0, 0, NULL, mask);
2867 2868 2869 2870
	}
	return ret;
}

2871 2872 2873 2874 2875 2876
/*
 * 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,
2877 2878
			       struct extent_io_tree *tree, struct page *page,
			       gfp_t mask)
2879 2880 2881 2882
{
	struct extent_map *em;
	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
	u64 end = start + PAGE_CACHE_SIZE - 1;
2883

2884 2885
	if ((mask & __GFP_WAIT) &&
	    page->mapping->host->i_size > 16 * 1024 * 1024) {
2886
		u64 len;
2887
		while (start <= end) {
2888
			len = end - start + 1;
2889
			write_lock(&map->lock);
2890
			em = lookup_extent_mapping(map, start, len);
2891
			if (!em || IS_ERR(em)) {
2892
				write_unlock(&map->lock);
2893 2894
				break;
			}
2895 2896
			if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
			    em->start != start) {
2897
				write_unlock(&map->lock);
2898 2899 2900 2901 2902
				free_extent_map(em);
				break;
			}
			if (!test_range_bit(tree, em->start,
					    extent_map_end(em) - 1,
2903
					    EXTENT_LOCKED | EXTENT_WRITEBACK,
2904
					    0, NULL)) {
2905 2906 2907 2908 2909
				remove_extent_mapping(map, em);
				/* once for the rb tree */
				free_extent_map(em);
			}
			start = extent_map_end(em);
2910
			write_unlock(&map->lock);
2911 2912

			/* once for us */
2913 2914 2915
			free_extent_map(em);
		}
	}
2916
	return try_release_extent_state(map, tree, page, mask);
2917 2918 2919 2920 2921 2922 2923 2924
}

sector_t extent_bmap(struct address_space *mapping, sector_t iblock,
		get_extent_t *get_extent)
{
	struct inode *inode = mapping->host;
	u64 start = iblock << inode->i_blkbits;
	sector_t sector = 0;
Y
Yan Zheng 已提交
2925
	size_t blksize = (1 << inode->i_blkbits);
2926 2927
	struct extent_map *em;

Y
Yan Zheng 已提交
2928 2929 2930 2931 2932
	lock_extent(&BTRFS_I(inode)->io_tree, start, start + blksize - 1,
		    GFP_NOFS);
	em = get_extent(inode, NULL, 0, start, blksize, 0);
	unlock_extent(&BTRFS_I(inode)->io_tree, start, start + blksize - 1,
		      GFP_NOFS);
2933 2934 2935
	if (!em || IS_ERR(em))
		return 0;

Y
Yan Zheng 已提交
2936
	if (em->block_start > EXTENT_MAP_LAST_BYTE)
2937 2938 2939 2940 2941 2942 2943 2944
		goto out;

	sector = (em->block_start + start - em->start) >> inode->i_blkbits;
out:
	free_extent_map(em);
	return sector;
}

Y
Yehuda Sadeh 已提交
2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981
int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
		__u64 start, __u64 len, get_extent_t *get_extent)
{
	int ret;
	u64 off = start;
	u64 max = start + len;
	u32 flags = 0;
	u64 disko = 0;
	struct extent_map *em = NULL;
	int end = 0;
	u64 em_start = 0, em_len = 0;
	unsigned long emflags;
	ret = 0;

	if (len == 0)
		return -EINVAL;

	lock_extent(&BTRFS_I(inode)->io_tree, start, start + len,
		GFP_NOFS);
	em = get_extent(inode, NULL, 0, off, max - off, 0);
	if (!em)
		goto out;
	if (IS_ERR(em)) {
		ret = PTR_ERR(em);
		goto out;
	}
	while (!end) {
		off = em->start + em->len;
		if (off >= max)
			end = 1;

		em_start = em->start;
		em_len = em->len;

		disko = 0;
		flags = 0;

2982
		if (em->block_start == EXTENT_MAP_LAST_BYTE) {
Y
Yehuda Sadeh 已提交
2983 2984
			end = 1;
			flags |= FIEMAP_EXTENT_LAST;
2985
		} else if (em->block_start == EXTENT_MAP_HOLE) {
Y
Yehuda Sadeh 已提交
2986
			flags |= FIEMAP_EXTENT_UNWRITTEN;
2987
		} else if (em->block_start == EXTENT_MAP_INLINE) {
Y
Yehuda Sadeh 已提交
2988 2989
			flags |= (FIEMAP_EXTENT_DATA_INLINE |
				  FIEMAP_EXTENT_NOT_ALIGNED);
2990
		} else if (em->block_start == EXTENT_MAP_DELALLOC) {
Y
Yehuda Sadeh 已提交
2991 2992
			flags |= (FIEMAP_EXTENT_DELALLOC |
				  FIEMAP_EXTENT_UNKNOWN);
2993
		} else {
Y
Yehuda Sadeh 已提交
2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030
			disko = em->block_start;
		}
		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
			flags |= FIEMAP_EXTENT_ENCODED;

		emflags = em->flags;
		free_extent_map(em);
		em = NULL;

		if (!end) {
			em = get_extent(inode, NULL, 0, off, max - off, 0);
			if (!em)
				goto out;
			if (IS_ERR(em)) {
				ret = PTR_ERR(em);
				goto out;
			}
			emflags = em->flags;
		}
		if (test_bit(EXTENT_FLAG_VACANCY, &emflags)) {
			flags |= FIEMAP_EXTENT_LAST;
			end = 1;
		}

		ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
					em_len, flags);
		if (ret)
			goto out_free;
	}
out_free:
	free_extent_map(em);
out:
	unlock_extent(&BTRFS_I(inode)->io_tree, start, start + len,
			GFP_NOFS);
	return ret;
}

3031 3032 3033 3034 3035 3036 3037 3038 3039 3040
static inline struct page *extent_buffer_page(struct extent_buffer *eb,
					      unsigned long i)
{
	struct page *p;
	struct address_space *mapping;

	if (i == 0)
		return eb->first_page;
	i += eb->start >> PAGE_CACHE_SHIFT;
	mapping = eb->first_page->mapping;
C
Chris Mason 已提交
3041 3042
	if (!mapping)
		return NULL;
3043 3044 3045 3046 3047 3048 3049

	/*
	 * extent_buffer_page is only called after pinning the page
	 * by increasing the reference count.  So we know the page must
	 * be in the radix tree.
	 */
	rcu_read_lock();
3050
	p = radix_tree_lookup(&mapping->page_tree, i);
3051
	rcu_read_unlock();
3052

3053 3054 3055
	return p;
}

3056
static inline unsigned long num_extent_pages(u64 start, u64 len)
3057
{
3058 3059
	return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
		(start >> PAGE_CACHE_SHIFT);
3060 3061
}

3062 3063 3064 3065 3066 3067
static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
						   u64 start,
						   unsigned long len,
						   gfp_t mask)
{
	struct extent_buffer *eb = NULL;
3068
#if LEAK_DEBUG
3069
	unsigned long flags;
C
Chris Mason 已提交
3070
#endif
3071 3072 3073 3074

	eb = kmem_cache_zalloc(extent_buffer_cache, mask);
	eb->start = start;
	eb->len = len;
3075 3076 3077
	spin_lock_init(&eb->lock);
	init_waitqueue_head(&eb->lock_wq);

3078
#if LEAK_DEBUG
3079 3080 3081
	spin_lock_irqsave(&leak_lock, flags);
	list_add(&eb->leak_list, &buffers);
	spin_unlock_irqrestore(&leak_lock, flags);
C
Chris Mason 已提交
3082
#endif
3083 3084 3085 3086 3087 3088 3089
	atomic_set(&eb->refs, 1);

	return eb;
}

static void __free_extent_buffer(struct extent_buffer *eb)
{
3090
#if LEAK_DEBUG
3091 3092 3093 3094
	unsigned long flags;
	spin_lock_irqsave(&leak_lock, flags);
	list_del(&eb->leak_list);
	spin_unlock_irqrestore(&leak_lock, flags);
C
Chris Mason 已提交
3095
#endif
3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107
	kmem_cache_free(extent_buffer_cache, eb);
}

struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
					  u64 start, unsigned long len,
					  struct page *page0,
					  gfp_t mask)
{
	unsigned long num_pages = num_extent_pages(start, len);
	unsigned long i;
	unsigned long index = start >> PAGE_CACHE_SHIFT;
	struct extent_buffer *eb;
3108
	struct extent_buffer *exists = NULL;
3109 3110 3111 3112
	struct page *p;
	struct address_space *mapping = tree->mapping;
	int uptodate = 1;

3113 3114 3115 3116 3117
	spin_lock(&tree->buffer_lock);
	eb = buffer_search(tree, start);
	if (eb) {
		atomic_inc(&eb->refs);
		spin_unlock(&tree->buffer_lock);
J
Josef Bacik 已提交
3118
		mark_page_accessed(eb->first_page);
3119 3120 3121 3122
		return eb;
	}
	spin_unlock(&tree->buffer_lock);

3123
	eb = __alloc_extent_buffer(tree, start, len, mask);
3124
	if (!eb)
3125 3126 3127 3128 3129 3130 3131 3132 3133 3134
		return NULL;

	if (page0) {
		eb->first_page = page0;
		i = 1;
		index++;
		page_cache_get(page0);
		mark_page_accessed(page0);
		set_page_extent_mapped(page0);
		set_page_extent_head(page0, len);
3135
		uptodate = PageUptodate(page0);
3136 3137 3138 3139 3140 3141 3142
	} else {
		i = 0;
	}
	for (; i < num_pages; i++, index++) {
		p = find_or_create_page(mapping, index, mask | __GFP_HIGHMEM);
		if (!p) {
			WARN_ON(1);
3143
			goto free_eb;
3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157
		}
		set_page_extent_mapped(p);
		mark_page_accessed(p);
		if (i == 0) {
			eb->first_page = p;
			set_page_extent_head(p, len);
		} else {
			set_page_private(p, EXTENT_PAGE_PRIVATE);
		}
		if (!PageUptodate(p))
			uptodate = 0;
		unlock_page(p);
	}
	if (uptodate)
3158
		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3159

3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171
	spin_lock(&tree->buffer_lock);
	exists = buffer_tree_insert(tree, start, &eb->rb_node);
	if (exists) {
		/* add one reference for the caller */
		atomic_inc(&exists->refs);
		spin_unlock(&tree->buffer_lock);
		goto free_eb;
	}
	spin_unlock(&tree->buffer_lock);

	/* add one reference for the tree */
	atomic_inc(&eb->refs);
3172 3173
	return eb;

3174
free_eb:
3175
	if (!atomic_dec_and_test(&eb->refs))
3176 3177
		return exists;
	for (index = 1; index < i; index++)
3178
		page_cache_release(extent_buffer_page(eb, index));
3179
	page_cache_release(extent_buffer_page(eb, 0));
3180
	__free_extent_buffer(eb);
3181
	return exists;
3182 3183 3184 3185 3186 3187 3188 3189
}

struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
					 u64 start, unsigned long len,
					  gfp_t mask)
{
	struct extent_buffer *eb;

3190 3191 3192 3193 3194
	spin_lock(&tree->buffer_lock);
	eb = buffer_search(tree, start);
	if (eb)
		atomic_inc(&eb->refs);
	spin_unlock(&tree->buffer_lock);
3195

J
Josef Bacik 已提交
3196 3197 3198
	if (eb)
		mark_page_accessed(eb->first_page);

3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209
	return eb;
}

void free_extent_buffer(struct extent_buffer *eb)
{
	if (!eb)
		return;

	if (!atomic_dec_and_test(&eb->refs))
		return;

3210
	WARN_ON(1);
3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223
}

int clear_extent_buffer_dirty(struct extent_io_tree *tree,
			      struct extent_buffer *eb)
{
	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);
3224
		if (!PageDirty(page))
C
Chris Mason 已提交
3225 3226
			continue;

3227
		lock_page(page);
3228 3229 3230 3231 3232 3233
		if (i == 0)
			set_page_extent_head(page, eb->len);
		else
			set_page_private(page, EXTENT_PAGE_PRIVATE);

		clear_page_dirty_for_io(page);
3234
		spin_lock_irq(&page->mapping->tree_lock);
3235 3236 3237 3238 3239
		if (!PageDirty(page)) {
			radix_tree_tag_clear(&page->mapping->page_tree,
						page_index(page),
						PAGECACHE_TAG_DIRTY);
		}
3240
		spin_unlock_irq(&page->mapping->tree_lock);
3241
		unlock_page(page);
3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257
	}
	return 0;
}

int wait_on_extent_buffer_writeback(struct extent_io_tree *tree,
				    struct extent_buffer *eb)
{
	return wait_on_extent_writeback(tree, eb->start,
					eb->start + eb->len - 1);
}

int set_extent_buffer_dirty(struct extent_io_tree *tree,
			     struct extent_buffer *eb)
{
	unsigned long i;
	unsigned long num_pages;
3258
	int was_dirty = 0;
3259

3260
	was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
3261
	num_pages = num_extent_pages(eb->start, eb->len);
3262
	for (i = 0; i < num_pages; i++)
3263
		__set_page_dirty_nobuffers(extent_buffer_page(eb, i));
3264
	return was_dirty;
3265 3266
}

3267 3268 3269 3270 3271 3272 3273 3274
int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
				struct extent_buffer *eb)
{
	unsigned long i;
	struct page *page;
	unsigned long num_pages;

	num_pages = num_extent_pages(eb->start, eb->len);
3275
	clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3276 3277 3278 3279 3280

	clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
			      GFP_NOFS);
	for (i = 0; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
C
Chris Mason 已提交
3281 3282
		if (page)
			ClearPageUptodate(page);
3283 3284 3285 3286
	}
	return 0;
}

3287 3288 3289 3290 3291 3292 3293 3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309 3310
int set_extent_buffer_uptodate(struct extent_io_tree *tree,
				struct extent_buffer *eb)
{
	unsigned long i;
	struct page *page;
	unsigned long num_pages;

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

	set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
			    GFP_NOFS);
	for (i = 0; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
		if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
		    ((i == num_pages - 1) &&
		     ((eb->start + eb->len) & (PAGE_CACHE_SIZE - 1)))) {
			check_page_uptodate(tree, page);
			continue;
		}
		SetPageUptodate(page);
	}
	return 0;
}

3311 3312 3313 3314 3315 3316 3317 3318 3319
int extent_range_uptodate(struct extent_io_tree *tree,
			  u64 start, u64 end)
{
	struct page *page;
	int ret;
	int pg_uptodate = 1;
	int uptodate;
	unsigned long index;

3320
	ret = test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL);
3321 3322
	if (ret)
		return 1;
C
Chris Mason 已提交
3323
	while (start <= end) {
3324 3325 3326 3327 3328 3329 3330 3331 3332 3333 3334 3335 3336
		index = start >> PAGE_CACHE_SHIFT;
		page = find_get_page(tree->mapping, index);
		uptodate = PageUptodate(page);
		page_cache_release(page);
		if (!uptodate) {
			pg_uptodate = 0;
			break;
		}
		start += PAGE_CACHE_SIZE;
	}
	return pg_uptodate;
}

3337
int extent_buffer_uptodate(struct extent_io_tree *tree,
3338
			   struct extent_buffer *eb)
3339
{
3340
	int ret = 0;
3341 3342
	unsigned long num_pages;
	unsigned long i;
3343 3344 3345
	struct page *page;
	int pg_uptodate = 1;

3346
	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
C
Chris Mason 已提交
3347
		return 1;
3348

C
Chris Mason 已提交
3349
	ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3350
			   EXTENT_UPTODATE, 1, NULL);
C
Chris Mason 已提交
3351 3352
	if (ret)
		return ret;
3353 3354 3355 3356 3357 3358 3359 3360 3361

	num_pages = num_extent_pages(eb->start, eb->len);
	for (i = 0; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
		if (!PageUptodate(page)) {
			pg_uptodate = 0;
			break;
		}
	}
C
Chris Mason 已提交
3362
	return pg_uptodate;
3363 3364 3365 3366
}

int read_extent_buffer_pages(struct extent_io_tree *tree,
			     struct extent_buffer *eb,
3367
			     u64 start, int wait,
3368
			     get_extent_t *get_extent, int mirror_num)
3369 3370 3371 3372 3373 3374
{
	unsigned long i;
	unsigned long start_i;
	struct page *page;
	int err;
	int ret = 0;
3375 3376 3377
	int locked_pages = 0;
	int all_uptodate = 1;
	int inc_all_pages = 0;
3378
	unsigned long num_pages;
3379
	struct bio *bio = NULL;
C
Chris Mason 已提交
3380
	unsigned long bio_flags = 0;
3381

3382
	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
3383 3384
		return 0;

3385
	if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3386
			   EXTENT_UPTODATE, 1, NULL)) {
3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401
		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);
		if (!wait) {
3402
			if (!trylock_page(page))
3403
				goto unlock_exit;
3404 3405 3406
		} else {
			lock_page(page);
		}
3407
		locked_pages++;
C
Chris Mason 已提交
3408
		if (!PageUptodate(page))
3409 3410 3411 3412
			all_uptodate = 0;
	}
	if (all_uptodate) {
		if (start_i == 0)
3413
			set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3414 3415 3416 3417 3418 3419 3420 3421 3422 3423
		goto unlock_exit;
	}

	for (i = start_i; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
		if (inc_all_pages)
			page_cache_get(page);
		if (!PageUptodate(page)) {
			if (start_i == 0)
				inc_all_pages = 1;
3424
			ClearPageError(page);
3425
			err = __extent_read_full_page(tree, page,
3426
						      get_extent, &bio,
C
Chris Mason 已提交
3427
						      mirror_num, &bio_flags);
C
Chris Mason 已提交
3428
			if (err)
3429 3430 3431 3432 3433 3434
				ret = err;
		} else {
			unlock_page(page);
		}
	}

3435
	if (bio)
C
Chris Mason 已提交
3436
		submit_one_bio(READ, bio, mirror_num, bio_flags);
3437

C
Chris Mason 已提交
3438
	if (ret || !wait)
3439
		return ret;
C
Chris Mason 已提交
3440

3441 3442 3443
	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
3444
		if (!PageUptodate(page))
3445 3446
			ret = -EIO;
	}
C
Chris Mason 已提交
3447

3448
	if (!ret)
3449
		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3450
	return ret;
3451 3452 3453

unlock_exit:
	i = start_i;
C
Chris Mason 已提交
3454
	while (locked_pages > 0) {
3455 3456 3457 3458 3459 3460
		page = extent_buffer_page(eb, i);
		i++;
		unlock_page(page);
		locked_pages--;
	}
	return ret;
3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479
}

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);

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

C
Chris Mason 已提交
3480
	while (len > 0) {
3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517
		page = extent_buffer_page(eb, i);

		cur = min(len, (PAGE_CACHE_SIZE - offset));
		kaddr = kmap_atomic(page, KM_USER1);
		memcpy(dst, kaddr + offset, cur);
		kunmap_atomic(kaddr, KM_USER1);

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

int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
			       unsigned long min_len, char **token, char **map,
			       unsigned long *map_start,
			       unsigned long *map_len, int km)
{
	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
3518

3519
	if (start + min_len > eb->len) {
C
Chris Mason 已提交
3520 3521 3522
		printk(KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
		       "wanted %lu %lu\n", (unsigned long long)eb->start,
		       eb->len, start, min_len);
3523 3524 3525 3526 3527 3528 3529 3530 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 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579 3580
		WARN_ON(1);
	}

	p = extent_buffer_page(eb, i);
	kaddr = kmap_atomic(p, km);
	*token = kaddr;
	*map = kaddr + offset;
	*map_len = PAGE_CACHE_SIZE - offset;
	return 0;
}

int map_extent_buffer(struct extent_buffer *eb, unsigned long start,
		      unsigned long min_len,
		      char **token, char **map,
		      unsigned long *map_start,
		      unsigned long *map_len, int km)
{
	int err;
	int save = 0;
	if (eb->map_token) {
		unmap_extent_buffer(eb, eb->map_token, km);
		eb->map_token = NULL;
		save = 1;
	}
	err = map_private_extent_buffer(eb, start, min_len, token, map,
				       map_start, map_len, km);
	if (!err && save) {
		eb->map_token = *token;
		eb->kaddr = *map;
		eb->map_start = *map_start;
		eb->map_len = *map_len;
	}
	return err;
}

void unmap_extent_buffer(struct extent_buffer *eb, char *token, int km)
{
	kunmap_atomic(token, km);
}

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);

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

C
Chris Mason 已提交
3581
	while (len > 0) {
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 3610 3611 3612 3613 3614 3615
		page = extent_buffer_page(eb, i);

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

		kaddr = kmap_atomic(page, KM_USER0);
		ret = memcmp(ptr, kaddr + offset, cur);
		kunmap_atomic(kaddr, KM_USER0);
		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);

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

C
Chris Mason 已提交
3616
	while (len > 0) {
3617 3618 3619 3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646
		page = extent_buffer_page(eb, i);
		WARN_ON(!PageUptodate(page));

		cur = min(len, PAGE_CACHE_SIZE - offset);
		kaddr = kmap_atomic(page, KM_USER1);
		memcpy(kaddr + offset, src, cur);
		kunmap_atomic(kaddr, KM_USER1);

		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);

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

C
Chris Mason 已提交
3647
	while (len > 0) {
3648 3649 3650 3651 3652 3653 3654 3655 3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678
		page = extent_buffer_page(eb, i);
		WARN_ON(!PageUptodate(page));

		cur = min(len, PAGE_CACHE_SIZE - offset);
		kaddr = kmap_atomic(page, KM_USER0);
		memset(kaddr + offset, c, cur);
		kunmap_atomic(kaddr, KM_USER0);

		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) &
		((unsigned long)PAGE_CACHE_SIZE - 1);

C
Chris Mason 已提交
3679
	while (len > 0) {
3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691 3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728 3729 3730 3731 3732 3733 3734 3735 3736 3737 3738 3739 3740 3741 3742 3743 3744
		page = extent_buffer_page(dst, i);
		WARN_ON(!PageUptodate(page));

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

		kaddr = kmap_atomic(page, KM_USER0);
		read_extent_buffer(src, kaddr + offset, src_offset, cur);
		kunmap_atomic(kaddr, KM_USER0);

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

static void move_pages(struct page *dst_page, struct page *src_page,
		       unsigned long dst_off, unsigned long src_off,
		       unsigned long len)
{
	char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
	if (dst_page == src_page) {
		memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len);
	} else {
		char *src_kaddr = kmap_atomic(src_page, KM_USER1);
		char *p = dst_kaddr + dst_off + len;
		char *s = src_kaddr + src_off + len;

		while (len--)
			*--p = *--s;

		kunmap_atomic(src_kaddr, KM_USER1);
	}
	kunmap_atomic(dst_kaddr, KM_USER0);
}

static void copy_pages(struct page *dst_page, struct page *src_page,
		       unsigned long dst_off, unsigned long src_off,
		       unsigned long len)
{
	char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
	char *src_kaddr;

	if (dst_page != src_page)
		src_kaddr = kmap_atomic(src_page, KM_USER1);
	else
		src_kaddr = dst_kaddr;

	memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
	kunmap_atomic(dst_kaddr, KM_USER0);
	if (dst_page != src_page)
		kunmap_atomic(src_kaddr, KM_USER1);
}

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) {
C
Chris Mason 已提交
3745 3746
		printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
		       "len %lu dst len %lu\n", src_offset, len, dst->len);
3747 3748 3749
		BUG_ON(1);
	}
	if (dst_offset + len > dst->len) {
C
Chris Mason 已提交
3750 3751
		printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
		       "len %lu dst len %lu\n", dst_offset, len, dst->len);
3752 3753 3754
		BUG_ON(1);
	}

C
Chris Mason 已提交
3755
	while (len > 0) {
3756 3757 3758 3759 3760 3761 3762 3763 3764 3765 3766 3767 3768 3769 3770 3771 3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787 3788 3789 3790 3791
		dst_off_in_page = (start_offset + dst_offset) &
			((unsigned long)PAGE_CACHE_SIZE - 1);
		src_off_in_page = (start_offset + src_offset) &
			((unsigned long)PAGE_CACHE_SIZE - 1);

		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) {
C
Chris Mason 已提交
3792 3793
		printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
		       "len %lu len %lu\n", src_offset, len, dst->len);
3794 3795 3796
		BUG_ON(1);
	}
	if (dst_offset + len > dst->len) {
C
Chris Mason 已提交
3797 3798
		printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
		       "len %lu len %lu\n", dst_offset, len, dst->len);
3799 3800 3801 3802 3803 3804
		BUG_ON(1);
	}
	if (dst_offset < src_offset) {
		memcpy_extent_buffer(dst, dst_offset, src_offset, len);
		return;
	}
C
Chris Mason 已提交
3805
	while (len > 0) {
3806 3807 3808 3809 3810 3811 3812 3813 3814 3815 3816 3817 3818 3819 3820 3821 3822 3823 3824 3825
		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) &
			((unsigned long)PAGE_CACHE_SIZE - 1);
		src_off_in_page = (start_offset + src_end) &
			((unsigned long)PAGE_CACHE_SIZE - 1);

		cur = min_t(unsigned long, len, src_off_in_page + 1);
		cur = min(cur, dst_off_in_page + 1);
		move_pages(extent_buffer_page(dst, dst_i),
			   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;
	}
}
3826 3827 3828 3829 3830 3831 3832 3833 3834 3835 3836 3837 3838 3839 3840 3841 3842 3843

int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page)
{
	u64 start = page_offset(page);
	struct extent_buffer *eb;
	int ret = 1;
	unsigned long i;
	unsigned long num_pages;

	spin_lock(&tree->buffer_lock);
	eb = buffer_search(tree, start);
	if (!eb)
		goto out;

	if (atomic_read(&eb->refs) > 1) {
		ret = 0;
		goto out;
	}
3844 3845 3846 3847
	if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
		ret = 0;
		goto out;
	}
3848 3849
	/* at this point we can safely release the extent buffer */
	num_pages = num_extent_pages(eb->start, eb->len);
C
Christoph Hellwig 已提交
3850 3851
	for (i = 0; i < num_pages; i++)
		page_cache_release(extent_buffer_page(eb, i));
3852 3853 3854 3855 3856 3857
	rb_erase(&eb->rb_node, &tree->buffer);
	__free_extent_buffer(eb);
out:
	spin_unlock(&tree->buffer_lock);
	return ret;
}