extent_io.c 93.9 KB
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#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/bio.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/page-flags.h>
#include <linux/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)
{
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	tree->state = RB_ROOT;
	tree->buffer = RB_ROOT;
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	tree->ops = NULL;
	tree->dirty_bytes = 0;
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	spin_lock_init(&tree->lock);
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	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, int *bits)
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{
	if (tree->ops && tree->ops->set_bit_hook) {
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		return tree->ops->set_bit_hook(tree->mapping->host,
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					       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,
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			   struct extent_state *state, int *bits)
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{
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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,
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			int *bits)
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{
	struct rb_node *node;
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	int bits_to_set = *bits & ~EXTENT_CTLBITS;
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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;

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	if (bits_to_set & EXTENT_DIRTY)
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		tree->dirty_bytes += end - start + 1;
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	state->state |= bits_to_set;
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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,
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			    struct extent_state *state,
			    int *bits, int wake)
459
{
460
	int bits_to_clear = *bits & ~EXTENT_CTLBITS;
461
	int ret = state->state & bits_to_clear;
462

463
	if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
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		u64 range = state->end - state->start + 1;
		WARN_ON(range > tree->dirty_bytes);
		tree->dirty_bytes -= range;
	}
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	clear_state_cb(tree, state, bits);
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	state->state &= ~bits_to_clear;
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	if (wake)
		wake_up(&state->wq);
472
	if (state->state == 0) {
473
		if (state->tree) {
474
			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;
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	int clear = 0;
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	if (delete)
		bits |= ~EXTENT_CTLBITS;
	bits |= EXTENT_FIRST_DELALLOC;

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	if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
		clear = 1;
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again:
	if (!prealloc && (mask & __GFP_WAIT)) {
		prealloc = alloc_extent_state(mask);
		if (!prealloc)
			return -ENOMEM;
	}

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	spin_lock(&tree->lock);
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	if (cached_state) {
		cached = *cached_state;
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		if (clear) {
			*cached_state = NULL;
			cached_state = NULL;
		}

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		if (cached && cached->tree && cached->start == start) {
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			if (clear)
				atomic_dec(&cached->refs);
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			state = cached;
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			goto hit_next;
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		}
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		if (clear)
			free_extent_state(cached);
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	}
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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);
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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);
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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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616
	set |= clear_state_bit(tree, state, &bits, wake);
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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);
651
	spin_unlock(&tree->lock);
652
	schedule();
653
	spin_lock(&tree->lock);
654 655 656 657 658 659 660 661 662 663 664 665 666 667
	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;

668
	spin_lock(&tree->lock);
669 670 671 672 673 674
again:
	while (1) {
		/*
		 * this search will find all the extents that end after
		 * our range starts
		 */
675
		node = tree_search(tree, start);
676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696
		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()) {
697
			spin_unlock(&tree->lock);
698
			cond_resched();
699
			spin_lock(&tree->lock);
700 701 702
		}
	}
out:
703
	spin_unlock(&tree->lock);
704 705 706
	return 0;
}

J
Josef Bacik 已提交
707
static int set_state_bits(struct extent_io_tree *tree,
708
			   struct extent_state *state,
709
			   int *bits)
710
{
J
Josef Bacik 已提交
711
	int ret;
712
	int bits_to_set = *bits & ~EXTENT_CTLBITS;
J
Josef Bacik 已提交
713 714 715 716

	ret = set_state_cb(tree, state, bits);
	if (ret)
		return ret;
717
	if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
718 719 720
		u64 range = state->end - state->start + 1;
		tree->dirty_bytes += range;
	}
721
	state->state |= bits_to_set;
J
Josef Bacik 已提交
722 723

	return 0;
724 725
}

726 727 728 729 730 731 732 733 734 735 736
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);
		}
	}
}

737
/*
738 739
 * 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.
740
 *
741 742 743
 * 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.
744
 *
745
 * [start, end] is inclusive This takes the tree lock.
746
 */
747

C
Chris Mason 已提交
748
static int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
749
			  int bits, int exclusive_bits, u64 *failed_start,
750
			  struct extent_state **cached_state,
C
Chris Mason 已提交
751
			  gfp_t mask)
752 753 754 755 756 757 758
{
	struct extent_state *state;
	struct extent_state *prealloc = NULL;
	struct rb_node *node;
	int err = 0;
	u64 last_start;
	u64 last_end;
759

760
	bits |= EXTENT_FIRST_DELALLOC;
761 762 763 764 765 766 767
again:
	if (!prealloc && (mask & __GFP_WAIT)) {
		prealloc = alloc_extent_state(mask);
		if (!prealloc)
			return -ENOMEM;
	}

768
	spin_lock(&tree->lock);
769 770 771 772 773 774 775
	if (cached_state && *cached_state) {
		state = *cached_state;
		if (state->start == start && state->tree) {
			node = &state->rb_node;
			goto hit_next;
		}
	}
776 777 778 779
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
780
	node = tree_search(tree, start);
781
	if (!node) {
782
		err = insert_state(tree, prealloc, start, end, &bits);
783 784 785 786 787
		prealloc = NULL;
		BUG_ON(err == -EEXIST);
		goto out;
	}
	state = rb_entry(node, struct extent_state, rb_node);
C
Chris Mason 已提交
788
hit_next:
789 790 791 792 793 794 795 796 797 798
	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
799
		struct rb_node *next_node;
800
		if (state->state & exclusive_bits) {
801 802 803 804
			*failed_start = state->start;
			err = -EEXIST;
			goto out;
		}
805

806
		err = set_state_bits(tree, state, &bits);
J
Josef Bacik 已提交
807 808 809
		if (err)
			goto out;

810
		cache_state(state, cached_state);
811
		merge_state(tree, state);
812 813
		if (last_end == (u64)-1)
			goto out;
C
Chris Mason 已提交
814

815
		start = last_end + 1;
C
Chris Mason 已提交
816 817 818 819 820 821 822 823 824
		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;
			}
		}
825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844
		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) {
845
		if (state->state & exclusive_bits) {
846 847 848 849 850 851 852 853 854 855
			*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) {
856
			err = set_state_bits(tree, state, &bits);
J
Josef Bacik 已提交
857 858
			if (err)
				goto out;
859
			cache_state(state, cached_state);
860
			merge_state(tree, state);
861 862 863
			if (last_end == (u64)-1)
				goto out;
			start = last_end + 1;
864 865 866 867 868 869 870 871 872 873 874 875 876 877 878
		}
		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
879
			this_end = last_start - 1;
880
		err = insert_state(tree, prealloc, start, this_end,
881
				   &bits);
882
		BUG_ON(err == -EEXIST);
J
Josef Bacik 已提交
883 884
		if (err) {
			prealloc = NULL;
885
			goto out;
J
Josef Bacik 已提交
886 887 888
		}
		cache_state(prealloc, cached_state);
		prealloc = NULL;
889 890 891 892 893 894 895 896 897 898
		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) {
899
		if (state->state & exclusive_bits) {
900 901 902 903 904 905 906
			*failed_start = start;
			err = -EEXIST;
			goto out;
		}
		err = split_state(tree, state, prealloc, end + 1);
		BUG_ON(err == -EEXIST);

907
		err = set_state_bits(tree, prealloc, &bits);
J
Josef Bacik 已提交
908 909 910 911
		if (err) {
			prealloc = NULL;
			goto out;
		}
912
		cache_state(prealloc, cached_state);
913 914 915 916 917 918 919 920
		merge_state(tree, prealloc);
		prealloc = NULL;
		goto out;
	}

	goto search_again;

out:
921
	spin_unlock(&tree->lock);
922 923 924 925 926 927 928 929
	if (prealloc)
		free_extent_state(prealloc);

	return err;

search_again:
	if (start > end)
		goto out;
930
	spin_unlock(&tree->lock);
931 932 933 934 935 936 937 938 939 940
	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,
941
			      NULL, mask);
942 943 944 945 946 947
}

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,
948
			      NULL, mask);
949 950 951 952 953
}

int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
		      int bits, gfp_t mask)
{
954
	return clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask);
955 956 957
}

int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
958
			struct extent_state **cached_state, gfp_t mask)
959 960
{
	return set_extent_bit(tree, start, end,
C
Chris Mason 已提交
961
			      EXTENT_DELALLOC | EXTENT_DIRTY | EXTENT_UPTODATE,
962
			      0, NULL, cached_state, mask);
963 964 965 966 967 968
}

int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
		       gfp_t mask)
{
	return clear_extent_bit(tree, start, end,
969
				EXTENT_DIRTY | EXTENT_DELALLOC |
970
				EXTENT_DO_ACCOUNTING, 0, 0, NULL, mask);
971 972 973 974 975 976
}

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,
977
			      NULL, mask);
978 979
}

980
static int clear_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
981 982
		       gfp_t mask)
{
983 984
	return clear_extent_bit(tree, start, end, EXTENT_NEW, 0, 0,
				NULL, mask);
985 986 987 988 989 990
}

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,
991
			      NULL, mask);
992 993
}

C
Chris Mason 已提交
994
static int clear_extent_uptodate(struct extent_io_tree *tree, u64 start,
995 996
				 u64 end, struct extent_state **cached_state,
				 gfp_t mask)
997
{
998
	return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
999
				cached_state, mask);
1000 1001 1002 1003 1004 1005 1006
}

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
1007 1008 1009 1010
/*
 * either insert or lock state struct between start and end use mask to tell
 * us if waiting is desired.
 */
1011
int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
1012
		     int bits, struct extent_state **cached_state, gfp_t mask)
1013 1014 1015 1016
{
	int err;
	u64 failed_start;
	while (1) {
1017
		err = set_extent_bit(tree, start, end, EXTENT_LOCKED | bits,
1018 1019
				     EXTENT_LOCKED, &failed_start,
				     cached_state, mask);
1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030
		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;
}

1031 1032
int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
{
1033
	return lock_extent_bits(tree, start, end, 0, NULL, mask);
1034 1035
}

1036 1037 1038 1039 1040 1041
int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end,
		    gfp_t mask)
{
	int err;
	u64 failed_start;

1042 1043
	err = set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
			     &failed_start, NULL, mask);
Y
Yan Zheng 已提交
1044 1045 1046
	if (err == -EEXIST) {
		if (failed_start > start)
			clear_extent_bit(tree, start, failed_start - 1,
1047
					 EXTENT_LOCKED, 1, 0, NULL, mask);
1048
		return 0;
Y
Yan Zheng 已提交
1049
	}
1050 1051 1052
	return 1;
}

1053 1054 1055 1056 1057 1058 1059
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);
}

1060 1061 1062
int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end,
		  gfp_t mask)
{
1063 1064
	return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
				mask);
1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088
}

/*
 * 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
 */
1089
static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104
{
	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
1105 1106 1107 1108 1109 1110 1111
/*
 * 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
 */
1112 1113 1114 1115 1116 1117 1118
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;

1119
	spin_lock(&tree->lock);
1120 1121 1122 1123
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1124
	node = tree_search(tree, start);
C
Chris Mason 已提交
1125
	if (!node)
1126 1127
		goto out;

C
Chris Mason 已提交
1128
	while (1) {
1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140
		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:
1141
	spin_unlock(&tree->lock);
1142 1143 1144
	return ret;
}

C
Chris Mason 已提交
1145 1146 1147 1148
/* 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
1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159
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
1160
	if (!node)
C
Chris Mason 已提交
1161 1162
		goto out;

C
Chris Mason 已提交
1163
	while (1) {
C
Chris Mason 已提交
1164
		state = rb_entry(node, struct extent_state, rb_node);
C
Chris Mason 已提交
1165
		if (state->end >= start && (state->state & bits))
C
Chris Mason 已提交
1166
			return state;
C
Chris Mason 已提交
1167

C
Chris Mason 已提交
1168 1169 1170 1171 1172 1173 1174 1175
		node = rb_next(node);
		if (!node)
			break;
	}
out:
	return NULL;
}

C
Chris Mason 已提交
1176 1177 1178 1179 1180 1181
/*
 * 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
1182
static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
1183 1184
					u64 *start, u64 *end, u64 max_bytes,
					struct extent_state **cached_state)
1185 1186 1187 1188 1189 1190 1191
{
	struct rb_node *node;
	struct extent_state *state;
	u64 cur_start = *start;
	u64 found = 0;
	u64 total_bytes = 0;

1192
	spin_lock(&tree->lock);
C
Chris Mason 已提交
1193

1194 1195 1196 1197
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1198
	node = tree_search(tree, cur_start);
1199
	if (!node) {
1200 1201
		if (!found)
			*end = (u64)-1;
1202 1203 1204
		goto out;
	}

C
Chris Mason 已提交
1205
	while (1) {
1206
		state = rb_entry(node, struct extent_state, rb_node);
1207 1208
		if (found && (state->start != cur_start ||
			      (state->state & EXTENT_BOUNDARY))) {
1209 1210 1211 1212 1213 1214 1215
			goto out;
		}
		if (!(state->state & EXTENT_DELALLOC)) {
			if (!found)
				*end = state->end;
			goto out;
		}
1216
		if (!found) {
1217
			*start = state->start;
1218 1219 1220
			*cached_state = state;
			atomic_inc(&state->refs);
		}
1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231
		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:
1232
	spin_unlock(&tree->lock);
1233 1234 1235
	return found;
}

C
Chris Mason 已提交
1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249
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
1250
	while (nr_pages > 0) {
C
Chris Mason 已提交
1251
		ret = find_get_pages_contig(inode->i_mapping, index,
1252 1253
				     min_t(unsigned long, nr_pages,
				     ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285
		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
1286
	while (nrpages > 0) {
C
Chris Mason 已提交
1287
		ret = find_get_pages_contig(inode->i_mapping, index,
1288 1289
				     min_t(unsigned long,
				     nrpages, ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1290 1291 1292 1293 1294 1295 1296 1297 1298 1299
		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
			 */
1300
			if (pages[i] != locked_page) {
C
Chris Mason 已提交
1301
				lock_page(pages[i]);
1302 1303
				if (!PageDirty(pages[i]) ||
				    pages[i]->mapping != inode->i_mapping) {
1304 1305 1306 1307 1308 1309
					ret = -EAGAIN;
					unlock_page(pages[i]);
					page_cache_release(pages[i]);
					goto done;
				}
			}
C
Chris Mason 已提交
1310
			page_cache_release(pages[i]);
1311
			pages_locked++;
C
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1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342
		}
		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;
1343
	struct extent_state *cached_state = NULL;
C
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1344 1345 1346 1347 1348 1349 1350 1351
	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,
1352
				    max_bytes, &cached_state);
C
Chris Mason 已提交
1353
	if (!found || delalloc_end <= *start) {
C
Chris Mason 已提交
1354 1355
		*start = delalloc_start;
		*end = delalloc_end;
1356
		free_extent_state(cached_state);
C
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1357 1358 1359
		return found;
	}

C
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1360 1361 1362 1363 1364
	/*
	 * 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
1365
	if (delalloc_start < *start)
C
Chris Mason 已提交
1366 1367
		delalloc_start = *start;

C
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1368 1369 1370 1371
	/*
	 * make sure to limit the number of pages we try to lock down
	 * if we're looping.
	 */
C
Chris Mason 已提交
1372
	if (delalloc_end + 1 - delalloc_start > max_bytes && loops)
1373
		delalloc_end = delalloc_start + PAGE_CACHE_SIZE - 1;
C
Chris Mason 已提交
1374

C
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1375 1376 1377 1378 1379 1380 1381
	/* 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
		 */
1382
		free_extent_state(cached_state);
C
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1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395
		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 */
1396 1397
	lock_extent_bits(tree, delalloc_start, delalloc_end,
			 0, &cached_state, GFP_NOFS);
C
Chris Mason 已提交
1398 1399 1400

	/* then test to make sure it is all still delalloc */
	ret = test_range_bit(tree, delalloc_start, delalloc_end,
1401
			     EXTENT_DELALLOC, 1, cached_state);
C
Chris Mason 已提交
1402
	if (!ret) {
1403 1404
		unlock_extent_cached(tree, delalloc_start, delalloc_end,
				     &cached_state, GFP_NOFS);
C
Chris Mason 已提交
1405 1406 1407 1408 1409
		__unlock_for_delalloc(inode, locked_page,
			      delalloc_start, delalloc_end);
		cond_resched();
		goto again;
	}
1410
	free_extent_state(cached_state);
C
Chris Mason 已提交
1411 1412 1413 1414 1415 1416 1417 1418 1419
	*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,
1420
				unsigned long op)
C
Chris Mason 已提交
1421 1422 1423 1424 1425 1426 1427
{
	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;
1428
	int clear_bits = 0;
C
Chris Mason 已提交
1429

1430
	if (op & EXTENT_CLEAR_UNLOCK)
1431
		clear_bits |= EXTENT_LOCKED;
1432
	if (op & EXTENT_CLEAR_DIRTY)
C
Chris Mason 已提交
1433 1434
		clear_bits |= EXTENT_DIRTY;

1435
	if (op & EXTENT_CLEAR_DELALLOC)
1436 1437
		clear_bits |= EXTENT_DELALLOC;

1438
	clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
1439 1440 1441
	if (!(op & (EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
		    EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK |
		    EXTENT_SET_PRIVATE2)))
1442
		return 0;
C
Chris Mason 已提交
1443

C
Chris Mason 已提交
1444
	while (nr_pages > 0) {
C
Chris Mason 已提交
1445
		ret = find_get_pages_contig(inode->i_mapping, index,
1446 1447
				     min_t(unsigned long,
				     nr_pages, ARRAY_SIZE(pages)), pages);
C
Chris Mason 已提交
1448
		for (i = 0; i < ret; i++) {
1449

1450
			if (op & EXTENT_SET_PRIVATE2)
1451 1452
				SetPagePrivate2(pages[i]);

C
Chris Mason 已提交
1453 1454 1455 1456
			if (pages[i] == locked_page) {
				page_cache_release(pages[i]);
				continue;
			}
1457
			if (op & EXTENT_CLEAR_DIRTY)
C
Chris Mason 已提交
1458
				clear_page_dirty_for_io(pages[i]);
1459
			if (op & EXTENT_SET_WRITEBACK)
C
Chris Mason 已提交
1460
				set_page_writeback(pages[i]);
1461
			if (op & EXTENT_END_WRITEBACK)
C
Chris Mason 已提交
1462
				end_page_writeback(pages[i]);
1463
			if (op & EXTENT_CLEAR_UNLOCK_PAGE)
1464
				unlock_page(pages[i]);
C
Chris Mason 已提交
1465 1466 1467 1468 1469 1470 1471 1472 1473
			page_cache_release(pages[i]);
		}
		nr_pages -= ret;
		index += ret;
		cond_resched();
	}
	return 0;
}

C
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1474 1475 1476 1477 1478
/*
 * 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.
 */
1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493
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;
	}

1494
	spin_lock(&tree->lock);
1495 1496 1497 1498 1499 1500 1501 1502
	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.
	 */
1503
	node = tree_search(tree, cur_start);
C
Chris Mason 已提交
1504
	if (!node)
1505 1506
		goto out;

C
Chris Mason 已提交
1507
	while (1) {
1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525
		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:
1526
	spin_unlock(&tree->lock);
1527 1528
	return total_bytes;
}
1529

C
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1530 1531 1532 1533
/*
 * set the private field for a given byte offset in the tree.  If there isn't
 * an extent_state there already, this does nothing.
 */
1534 1535 1536 1537 1538 1539
int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
{
	struct rb_node *node;
	struct extent_state *state;
	int ret = 0;

1540
	spin_lock(&tree->lock);
1541 1542 1543 1544
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1545
	node = tree_search(tree, start);
1546
	if (!node) {
1547 1548 1549 1550 1551 1552 1553 1554 1555 1556
		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:
1557
	spin_unlock(&tree->lock);
1558 1559 1560 1561 1562 1563 1564 1565 1566
	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;

1567
	spin_lock(&tree->lock);
1568 1569 1570 1571
	/*
	 * this search will find all the extents that end after
	 * our range starts.
	 */
1572
	node = tree_search(tree, start);
1573
	if (!node) {
1574 1575 1576 1577 1578 1579 1580 1581 1582 1583
		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:
1584
	spin_unlock(&tree->lock);
1585 1586 1587 1588 1589
	return ret;
}

/*
 * searches a range in the state tree for a given mask.
1590
 * If 'filled' == 1, this returns 1 only if every extent in the tree
1591 1592 1593 1594
 * 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,
1595
		   int bits, int filled, struct extent_state *cached)
1596 1597 1598 1599 1600
{
	struct extent_state *state = NULL;
	struct rb_node *node;
	int bitset = 0;

1601
	spin_lock(&tree->lock);
1602 1603 1604 1605
	if (cached && cached->tree && cached->start == start)
		node = &cached->rb_node;
	else
		node = tree_search(tree, start);
1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624
	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;
		}
1625 1626 1627 1628

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

1629 1630 1631 1632 1633 1634 1635 1636 1637 1638
		start = state->end + 1;
		if (start > end)
			break;
		node = rb_next(node);
		if (!node) {
			if (filled)
				bitset = 0;
			break;
		}
	}
1639
	spin_unlock(&tree->lock);
1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651
	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;
1652
	if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665
		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;
1666
	if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL))
1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677
		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)
{
1678
	end_page_writeback(page);
1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694
	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)
{
1695
	int uptodate = err == 0;
1696
	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
1697
	struct extent_io_tree *tree;
1698 1699 1700
	u64 start;
	u64 end;
	int whole_page;
1701
	int ret;
1702 1703 1704

	do {
		struct page *page = bvec->bv_page;
1705 1706
		tree = &BTRFS_I(page->mapping->host)->io_tree;

1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717
		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);
1718 1719
		if (tree->ops && tree->ops->writepage_end_io_hook) {
			ret = tree->ops->writepage_end_io_hook(page, start,
1720
						       end, NULL, uptodate);
1721 1722 1723 1724 1725 1726 1727
			if (ret)
				uptodate = 0;
		}

		if (!uptodate && tree->ops &&
		    tree->ops->writepage_io_failed_hook) {
			ret = tree->ops->writepage_io_failed_hook(bio, page,
1728
							 start, end, NULL);
1729 1730 1731 1732 1733 1734
			if (ret == 0) {
				uptodate = (err == 0);
				continue;
			}
		}

1735
		if (!uptodate) {
1736
			clear_extent_uptodate(tree, start, end, NULL, GFP_NOFS);
1737 1738 1739
			ClearPageUptodate(page);
			SetPageError(page);
		}
1740

1741 1742 1743 1744 1745
		if (whole_page)
			end_page_writeback(page);
		else
			check_page_writeback(tree, page);
	} while (bvec >= bio->bi_io_vec);
1746

1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763
	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);
1764 1765
	struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
	struct bio_vec *bvec = bio->bi_io_vec;
1766
	struct extent_io_tree *tree;
1767 1768 1769 1770 1771
	u64 start;
	u64 end;
	int whole_page;
	int ret;

1772 1773 1774
	if (err)
		uptodate = 0;

1775 1776
	do {
		struct page *page = bvec->bv_page;
1777 1778
		tree = &BTRFS_I(page->mapping->host)->io_tree;

1779 1780 1781 1782 1783 1784 1785 1786 1787
		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;

1788
		if (++bvec <= bvec_end)
1789 1790 1791
			prefetchw(&bvec->bv_page->flags);

		if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
1792
			ret = tree->ops->readpage_end_io_hook(page, start, end,
1793
							      NULL);
1794 1795 1796
			if (ret)
				uptodate = 0;
		}
1797 1798 1799
		if (!uptodate && tree->ops &&
		    tree->ops->readpage_io_failed_hook) {
			ret = tree->ops->readpage_io_failed_hook(bio, page,
1800
							 start, end, NULL);
1801
			if (ret == 0) {
1802 1803
				uptodate =
					test_bit(BIO_UPTODATE, &bio->bi_flags);
1804 1805
				if (err)
					uptodate = 0;
1806 1807 1808
				continue;
			}
		}
1809

1810
		if (uptodate) {
1811 1812
			set_extent_uptodate(tree, start, end,
					    GFP_ATOMIC);
1813
		}
1814
		unlock_extent(tree, start, end, GFP_ATOMIC);
1815

1816 1817 1818 1819 1820 1821 1822
		if (whole_page) {
			if (uptodate) {
				SetPageUptodate(page);
			} else {
				ClearPageUptodate(page);
				SetPageError(page);
			}
1823
			unlock_page(page);
1824 1825 1826 1827 1828 1829 1830
		} else {
			if (uptodate) {
				check_page_uptodate(tree, page);
			} else {
				ClearPageUptodate(page);
				SetPageError(page);
			}
1831
			check_page_locked(tree, page);
1832
		}
1833
	} while (bvec <= bvec_end);
1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846

	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;
1847
	struct extent_io_tree *tree;
1848 1849 1850 1851 1852
	u64 start;
	u64 end;

	do {
		struct page *page = bvec->bv_page;
1853 1854
		tree = &BTRFS_I(page->mapping->host)->io_tree;

1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889
		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) {
1890
		bio->bi_size = 0;
1891 1892 1893 1894 1895 1896
		bio->bi_bdev = bdev;
		bio->bi_sector = first_sector;
	}
	return bio;
}

C
Chris Mason 已提交
1897 1898
static int submit_one_bio(int rw, struct bio *bio, int mirror_num,
			  unsigned long bio_flags)
1899 1900
{
	int ret = 0;
1901 1902 1903 1904 1905 1906 1907 1908 1909
	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;

1910
	bio->bi_private = NULL;
1911 1912 1913

	bio_get(bio);

1914
	if (tree->ops && tree->ops->submit_bio_hook)
1915
		tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
1916
					   mirror_num, bio_flags, start);
1917 1918
	else
		submit_bio(rw, bio);
1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930
	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,
1931
			      bio_end_io_t end_io_func,
C
Chris Mason 已提交
1932 1933 1934
			      int mirror_num,
			      unsigned long prev_bio_flags,
			      unsigned long bio_flags)
1935 1936 1937 1938
{
	int ret = 0;
	struct bio *bio;
	int nr;
C
Chris Mason 已提交
1939 1940 1941
	int contig = 0;
	int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
	int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
1942
	size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
1943 1944 1945

	if (bio_ret && *bio_ret) {
		bio = *bio_ret;
C
Chris Mason 已提交
1946 1947 1948 1949 1950 1951 1952
		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 ||
1953
		    (tree->ops && tree->ops->merge_bio_hook &&
C
Chris Mason 已提交
1954 1955 1956 1957 1958
		     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);
1959 1960 1961 1962 1963
			bio = NULL;
		} else {
			return 0;
		}
	}
C
Chris Mason 已提交
1964 1965 1966 1967 1968
	if (this_compressed)
		nr = BIO_MAX_PAGES;
	else
		nr = bio_get_nr_vecs(bdev);

1969
	bio = extent_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
1970

C
Chris Mason 已提交
1971
	bio_add_page(bio, page, page_size, offset);
1972 1973
	bio->bi_end_io = end_io_func;
	bio->bi_private = tree;
1974

C
Chris Mason 已提交
1975
	if (bio_ret)
1976
		*bio_ret = bio;
C
Chris Mason 已提交
1977
	else
C
Chris Mason 已提交
1978
		ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
1979 1980 1981 1982 1983 1984 1985 1986 1987

	return ret;
}

void set_page_extent_mapped(struct page *page)
{
	if (!PagePrivate(page)) {
		SetPagePrivate(page);
		page_cache_get(page);
1988
		set_page_private(page, EXTENT_PAGE_PRIVATE);
1989 1990 1991
	}
}

1992
static void set_page_extent_head(struct page *page, unsigned long len)
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
{
	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
2005 2006
				   struct bio **bio, int mirror_num,
				   unsigned long *bio_flags)
2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
{
	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;
2020
	struct btrfs_ordered_extent *ordered;
2021 2022 2023 2024
	int ret;
	int nr = 0;
	size_t page_offset = 0;
	size_t iosize;
C
Chris Mason 已提交
2025
	size_t disk_io_size;
2026
	size_t blocksize = inode->i_sb->s_blocksize;
C
Chris Mason 已提交
2027
	unsigned long this_bio_flag = 0;
2028 2029 2030 2031

	set_page_extent_mapped(page);

	end = page_end;
2032 2033 2034 2035 2036 2037 2038 2039 2040
	while (1) {
		lock_extent(tree, start, end, GFP_NOFS);
		ordered = btrfs_lookup_ordered_extent(inode, start);
		if (!ordered)
			break;
		unlock_extent(tree, start, end, GFP_NOFS);
		btrfs_start_ordered_extent(inode, ordered, 1);
		btrfs_put_ordered_extent(ordered);
	}
2041

C
Chris Mason 已提交
2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053
	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);
		}
	}
2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077
	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
2078 2079 2080
		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
			this_bio_flag = EXTENT_BIO_COMPRESSED;

2081 2082 2083
		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
2084 2085 2086 2087 2088 2089 2090
		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;
		}
2091 2092
		bdev = em->bdev;
		block_start = em->block_start;
Y
Yan Zheng 已提交
2093 2094
		if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
			block_start = EXTENT_MAP_HOLE;
2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113
		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 */
2114 2115
		if (test_range_bit(tree, cur, cur_end,
				   EXTENT_UPTODATE, 1, NULL)) {
2116
			check_page_uptodate(tree, page);
2117 2118 2119 2120 2121
			unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
			cur = cur + iosize;
			page_offset += iosize;
			continue;
		}
2122 2123 2124 2125 2126 2127 2128 2129 2130 2131
		/* 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;
		}
2132 2133 2134 2135 2136 2137 2138

		ret = 0;
		if (tree->ops && tree->ops->readpage_io_hook) {
			ret = tree->ops->readpage_io_hook(page, cur,
							  cur + iosize - 1);
		}
		if (!ret) {
2139 2140
			unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1;
			pnr -= page->index;
2141
			ret = submit_extent_page(READ, tree, page,
C
Chris Mason 已提交
2142
					 sector, disk_io_size, page_offset,
2143
					 bdev, bio, pnr,
C
Chris Mason 已提交
2144 2145 2146
					 end_bio_extent_readpage, mirror_num,
					 *bio_flags,
					 this_bio_flag);
2147
			nr++;
C
Chris Mason 已提交
2148
			*bio_flags = this_bio_flag;
2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166
		}
		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
2167
	unsigned long bio_flags = 0;
2168 2169
	int ret;

C
Chris Mason 已提交
2170 2171
	ret = __extent_read_full_page(tree, page, get_extent, &bio, 0,
				      &bio_flags);
2172
	if (bio)
C
Chris Mason 已提交
2173
		submit_one_bio(READ, bio, 0, bio_flags);
2174 2175 2176
	return ret;
}

2177 2178 2179 2180 2181 2182 2183 2184 2185 2186
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;
}

2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207
/*
 * 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;
2208
	u64 unlock_start;
2209
	sector_t sector;
2210
	struct extent_state *cached_state = NULL;
2211 2212 2213 2214
	struct extent_map *em;
	struct block_device *bdev;
	int ret;
	int nr = 0;
2215
	size_t pg_offset = 0;
2216 2217 2218 2219 2220
	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
2221 2222
	int page_started;
	int compressed;
2223
	int write_flags;
2224
	unsigned long nr_written = 0;
2225

2226 2227 2228 2229 2230
	if (wbc->sync_mode == WB_SYNC_ALL)
		write_flags = WRITE_SYNC_PLUG;
	else
		write_flags = WRITE;

2231
	WARN_ON(!PageLocked(page));
2232
	pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
2233
	if (page->index > end_index ||
2234
	   (page->index == end_index && !pg_offset)) {
2235
		page->mapping->a_ops->invalidatepage(page, 0);
2236 2237 2238 2239 2240 2241 2242 2243
		unlock_page(page);
		return 0;
	}

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

		userpage = kmap_atomic(page, KM_USER0);
2244 2245
		memset(userpage + pg_offset, 0,
		       PAGE_CACHE_SIZE - pg_offset);
2246
		kunmap_atomic(userpage, KM_USER0);
2247
		flush_dcache_page(page);
2248
	}
2249
	pg_offset = 0;
2250 2251 2252 2253 2254

	set_page_extent_mapped(page);

	delalloc_start = start;
	delalloc_end = 0;
C
Chris Mason 已提交
2255
	page_started = 0;
2256
	if (!epd->extent_locked) {
2257
		u64 delalloc_to_write = 0;
2258 2259 2260 2261 2262 2263
		/*
		 * 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
2264
		while (delalloc_end < page_end) {
2265
			nr_delalloc = find_lock_delalloc_range(inode, tree,
C
Chris Mason 已提交
2266 2267
						       page,
						       &delalloc_start,
2268 2269
						       &delalloc_end,
						       128 * 1024 * 1024);
2270 2271 2272 2273 2274 2275 2276
			if (nr_delalloc == 0) {
				delalloc_start = delalloc_end + 1;
				continue;
			}
			tree->ops->fill_delalloc(inode, page, delalloc_start,
						 delalloc_end, &page_started,
						 &nr_written);
2277 2278 2279 2280 2281 2282 2283 2284
			/*
			 * 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;
2285 2286
			delalloc_start = delalloc_end + 1;
		}
2287 2288 2289 2290 2291 2292 2293 2294
		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
2295

2296 2297 2298 2299 2300
		/* did the fill delalloc function already unlock and start
		 * the IO?
		 */
		if (page_started) {
			ret = 0;
2301 2302 2303 2304 2305 2306 2307
			/*
			 * 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;
2308
		}
C
Chris Mason 已提交
2309
	}
2310
	if (tree->ops && tree->ops->writepage_start_hook) {
C
Chris Mason 已提交
2311 2312
		ret = tree->ops->writepage_start_hook(page, start,
						      page_end);
2313 2314
		if (ret == -EAGAIN) {
			redirty_page_for_writepage(wbc, page);
2315
			update_nr_written(page, wbc, nr_written);
2316
			unlock_page(page);
2317
			ret = 0;
2318
			goto done_unlocked;
2319 2320 2321
		}
	}

2322 2323 2324 2325 2326
	/*
	 * 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);
2327

2328 2329
	end = page_end;
	if (last_byte <= start) {
2330 2331 2332 2333
		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;
2334 2335 2336 2337 2338 2339 2340
		goto done;
	}

	blocksize = inode->i_sb->s_blocksize;

	while (cur <= end) {
		if (cur >= last_byte) {
2341 2342 2343 2344
			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;
2345 2346
			break;
		}
2347
		em = epd->get_extent(inode, page, pg_offset, cur,
2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361
				     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
2362
		compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
2363 2364 2365
		free_extent_map(em);
		em = NULL;

C
Chris Mason 已提交
2366 2367 2368 2369 2370
		/*
		 * compressed and inline extents are written through other
		 * paths in the FS
		 */
		if (compressed || block_start == EXTENT_MAP_HOLE ||
2371
		    block_start == EXTENT_MAP_INLINE) {
C
Chris Mason 已提交
2372 2373 2374 2375 2376 2377
			/*
			 * end_io notification does not happen here for
			 * compressed extents
			 */
			if (!compressed && tree->ops &&
			    tree->ops->writepage_end_io_hook)
2378 2379 2380
				tree->ops->writepage_end_io_hook(page, cur,
							 cur + iosize - 1,
							 NULL, 1);
C
Chris Mason 已提交
2381 2382 2383 2384 2385 2386 2387 2388 2389
			else if (compressed) {
				/* we don't want to end_page_writeback on
				 * a compressed extent.  this happens
				 * elsewhere
				 */
				nr++;
			}

			cur += iosize;
2390
			pg_offset += iosize;
2391
			unlock_start = cur;
2392 2393 2394 2395
			continue;
		}
		/* leave this out until we have a page_mkwrite call */
		if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
2396
				   EXTENT_DIRTY, 0, NULL)) {
2397
			cur = cur + iosize;
2398
			pg_offset += iosize;
2399 2400
			continue;
		}
C
Chris Mason 已提交
2401

2402 2403 2404 2405 2406 2407
		if (tree->ops && tree->ops->writepage_io_hook) {
			ret = tree->ops->writepage_io_hook(page, cur,
						cur + iosize - 1);
		} else {
			ret = 0;
		}
2408
		if (ret) {
2409
			SetPageError(page);
2410
		} else {
2411
			unsigned long max_nr = end_index + 1;
2412

2413 2414
			set_range_writeback(tree, cur, cur + iosize - 1);
			if (!PageWriteback(page)) {
C
Chris Mason 已提交
2415 2416 2417
				printk(KERN_ERR "btrfs warning page %lu not "
				       "writeback, cur %llu end %llu\n",
				       page->index, (unsigned long long)cur,
2418 2419 2420
				       (unsigned long long)end);
			}

2421 2422 2423
			ret = submit_extent_page(write_flags, tree, page,
						 sector, iosize, pg_offset,
						 bdev, &epd->bio, max_nr,
C
Chris Mason 已提交
2424 2425
						 end_bio_extent_writepage,
						 0, 0, 0);
2426 2427 2428 2429
			if (ret)
				SetPageError(page);
		}
		cur = cur + iosize;
2430
		pg_offset += iosize;
2431 2432 2433 2434 2435 2436 2437 2438 2439
		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);
2440

2441 2442
done_unlocked:

2443 2444
	/* drop our reference on any cached states */
	free_extent_state(cached_state);
2445 2446 2447 2448
	return 0;
}

/**
C
Chris Mason 已提交
2449
 * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462
 * @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.
 */
2463
static int extent_write_cache_pages(struct extent_io_tree *tree,
C
Chris Mason 已提交
2464 2465
			     struct address_space *mapping,
			     struct writeback_control *wbc,
C
Chris Mason 已提交
2466 2467
			     writepage_t writepage, void *data,
			     void (*flush_fn)(void *))
2468 2469 2470
{
	int ret = 0;
	int done = 0;
2471
	int nr_to_write_done = 0;
2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490
	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:
2491
	while (!done && !nr_to_write_done && (index <= end) &&
2492
	       (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
C
Chris Mason 已提交
2493 2494
			      PAGECACHE_TAG_DIRTY, min(end - index,
				  (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507
		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
2508 2509 2510 2511
			if (tree->ops && tree->ops->write_cache_pages_lock_hook)
				tree->ops->write_cache_pages_lock_hook(page);
			else
				lock_page(page);
2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523

			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
2524
			if (wbc->sync_mode != WB_SYNC_NONE) {
2525 2526
				if (PageWriteback(page))
					flush_fn(data);
2527
				wait_on_page_writeback(page);
C
Chris Mason 已提交
2528
			}
2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541

			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;
			}
2542
			if (ret)
2543
				done = 1;
2544 2545 2546 2547 2548 2549 2550

			/*
			 * 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;
2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566
		}
		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;
}

2567
static void flush_epd_write_bio(struct extent_page_data *epd)
C
Chris Mason 已提交
2568 2569
{
	if (epd->bio) {
2570 2571 2572 2573
		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
2574 2575 2576 2577
		epd->bio = NULL;
	}
}

2578 2579 2580 2581 2582 2583
static noinline void flush_write_bio(void *data)
{
	struct extent_page_data *epd = data;
	flush_epd_write_bio(epd);
}

2584 2585 2586 2587 2588 2589 2590 2591 2592 2593
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,
2594
		.extent_locked = 0,
2595
		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
2596 2597 2598
	};
	struct writeback_control wbc_writepages = {
		.bdi		= wbc->bdi,
2599
		.sync_mode	= wbc->sync_mode,
2600 2601 2602 2603 2604 2605 2606 2607
		.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
2608
	extent_write_cache_pages(tree, mapping, &wbc_writepages,
C
Chris Mason 已提交
2609
				 __extent_writepage, &epd, flush_write_bio);
2610
	flush_epd_write_bio(&epd);
2611 2612 2613
	return ret;
}

2614 2615 2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628
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,
2629
		.sync_io = mode == WB_SYNC_ALL,
2630 2631 2632 2633 2634 2635 2636 2637 2638 2639
	};
	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
2640
	while (start <= end) {
2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654
		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;
	}

2655
	flush_epd_write_bio(&epd);
2656 2657
	return ret;
}
2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668

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,
2669
		.extent_locked = 0,
2670
		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
2671 2672
	};

C
Chris Mason 已提交
2673
	ret = extent_write_cache_pages(tree, mapping, wbc,
C
Chris Mason 已提交
2674 2675
				       __extent_writepage, &epd,
				       flush_write_bio);
2676
	flush_epd_write_bio(&epd);
2677 2678 2679 2680 2681 2682 2683 2684 2685 2686
	return ret;
}

int extent_readpages(struct extent_io_tree *tree,
		     struct address_space *mapping,
		     struct list_head *pages, unsigned nr_pages,
		     get_extent_t get_extent)
{
	struct bio *bio = NULL;
	unsigned page_idx;
C
Chris Mason 已提交
2687
	unsigned long bio_flags = 0;
2688 2689 2690 2691 2692 2693

	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);
2694
		if (!add_to_page_cache_lru(page, mapping,
2695
					page->index, GFP_KERNEL)) {
2696
			__extent_read_full_page(tree, page, get_extent,
C
Chris Mason 已提交
2697
						&bio, 0, &bio_flags);
2698 2699 2700 2701 2702
		}
		page_cache_release(page);
	}
	BUG_ON(!list_empty(pages));
	if (bio)
C
Chris Mason 已提交
2703
		submit_one_bio(READ, bio, 0, bio_flags);
2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714
	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)
{
2715
	struct extent_state *cached_state = NULL;
2716 2717 2718 2719
	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
2720
	start += (offset + blocksize - 1) & ~(blocksize - 1);
2721 2722 2723
	if (start > end)
		return 0;

2724
	lock_extent_bits(tree, start, end, 0, &cached_state, GFP_NOFS);
2725
	wait_on_page_writeback(page);
2726
	clear_extent_bit(tree, start, end,
2727 2728
			 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
			 EXTENT_DO_ACCOUNTING,
2729
			 1, 1, &cached_state, GFP_NOFS);
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 2771 2772 2773 2774 2775 2776 2777 2778 2779
	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
2780
	while (block_start <= block_end) {
2781 2782
		em = get_extent(inode, page, page_offset, block_start,
				block_end - block_start + 1, 1);
C
Chris Mason 已提交
2783
		if (IS_ERR(em) || !em)
2784
			goto err;
C
Chris Mason 已提交
2785

2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808
		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,
2809
				    EXTENT_UPTODATE, 1, NULL)) {
2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822
			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,
2823
				       EXTENT_LOCKED, 0, NULL, NULL, GFP_NOFS);
2824 2825 2826
			ret = submit_extent_page(READ, tree, page,
					 sector, iosize, page_offset, em->bdev,
					 NULL, 1,
C
Chris Mason 已提交
2827 2828
					 end_bio_extent_preparewrite, 0,
					 0, 0);
2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849
			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;
}

2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862
/*
 * 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;

2863
	if (test_range_bit(tree, start, end,
2864
			   EXTENT_IOBITS, 0, NULL))
2865 2866 2867 2868
		ret = 0;
	else {
		if ((mask & GFP_NOFS) == GFP_NOFS)
			mask = GFP_NOFS;
2869 2870 2871 2872 2873 2874 2875
		/*
		 * 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);
2876 2877 2878 2879
	}
	return ret;
}

2880 2881 2882 2883 2884 2885
/*
 * 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,
2886 2887
			       struct extent_io_tree *tree, struct page *page,
			       gfp_t mask)
2888 2889 2890 2891
{
	struct extent_map *em;
	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
	u64 end = start + PAGE_CACHE_SIZE - 1;
2892

2893 2894
	if ((mask & __GFP_WAIT) &&
	    page->mapping->host->i_size > 16 * 1024 * 1024) {
2895
		u64 len;
2896
		while (start <= end) {
2897
			len = end - start + 1;
2898
			write_lock(&map->lock);
2899
			em = lookup_extent_mapping(map, start, len);
2900
			if (!em || IS_ERR(em)) {
2901
				write_unlock(&map->lock);
2902 2903
				break;
			}
2904 2905
			if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
			    em->start != start) {
2906
				write_unlock(&map->lock);
2907 2908 2909 2910 2911
				free_extent_map(em);
				break;
			}
			if (!test_range_bit(tree, em->start,
					    extent_map_end(em) - 1,
2912
					    EXTENT_LOCKED | EXTENT_WRITEBACK,
2913
					    0, NULL)) {
2914 2915 2916 2917 2918
				remove_extent_mapping(map, em);
				/* once for the rb tree */
				free_extent_map(em);
			}
			start = extent_map_end(em);
2919
			write_unlock(&map->lock);
2920 2921

			/* once for us */
2922 2923 2924
			free_extent_map(em);
		}
	}
2925
	return try_release_extent_state(map, tree, page, mask);
2926 2927 2928 2929 2930 2931
}

sector_t extent_bmap(struct address_space *mapping, sector_t iblock,
		get_extent_t *get_extent)
{
	struct inode *inode = mapping->host;
2932
	struct extent_state *cached_state = NULL;
2933 2934
	u64 start = iblock << inode->i_blkbits;
	sector_t sector = 0;
Y
Yan Zheng 已提交
2935
	size_t blksize = (1 << inode->i_blkbits);
2936 2937
	struct extent_map *em;

2938 2939
	lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + blksize - 1,
			 0, &cached_state, GFP_NOFS);
Y
Yan Zheng 已提交
2940
	em = get_extent(inode, NULL, 0, start, blksize, 0);
2941 2942
	unlock_extent_cached(&BTRFS_I(inode)->io_tree, start,
			     start + blksize - 1, &cached_state, GFP_NOFS);
2943 2944 2945
	if (!em || IS_ERR(em))
		return 0;

Y
Yan Zheng 已提交
2946
	if (em->block_start > EXTENT_MAP_LAST_BYTE)
2947 2948 2949 2950 2951 2952 2953 2954
		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
2955 2956 2957 2958 2959 2960 2961 2962 2963
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;
2964
	struct extent_state *cached_state = NULL;
Y
Yehuda Sadeh 已提交
2965 2966 2967 2968 2969 2970 2971 2972
	int end = 0;
	u64 em_start = 0, em_len = 0;
	unsigned long emflags;
	ret = 0;

	if (len == 0)
		return -EINVAL;

2973 2974
	lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len, 0,
			 &cached_state, GFP_NOFS);
Y
Yehuda Sadeh 已提交
2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992
	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;

2993
		if (em->block_start == EXTENT_MAP_LAST_BYTE) {
Y
Yehuda Sadeh 已提交
2994 2995
			end = 1;
			flags |= FIEMAP_EXTENT_LAST;
2996
		} else if (em->block_start == EXTENT_MAP_HOLE) {
Y
Yehuda Sadeh 已提交
2997
			flags |= FIEMAP_EXTENT_UNWRITTEN;
2998
		} else if (em->block_start == EXTENT_MAP_INLINE) {
Y
Yehuda Sadeh 已提交
2999 3000
			flags |= (FIEMAP_EXTENT_DATA_INLINE |
				  FIEMAP_EXTENT_NOT_ALIGNED);
3001
		} else if (em->block_start == EXTENT_MAP_DELALLOC) {
Y
Yehuda Sadeh 已提交
3002 3003
			flags |= (FIEMAP_EXTENT_DELALLOC |
				  FIEMAP_EXTENT_UNKNOWN);
3004
		} else {
Y
Yehuda Sadeh 已提交
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 3031 3032 3033 3034 3035 3036
			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:
3037 3038
	unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len,
			     &cached_state, GFP_NOFS);
Y
Yehuda Sadeh 已提交
3039 3040 3041
	return ret;
}

3042 3043 3044 3045 3046 3047 3048 3049 3050 3051
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
3052 3053
	if (!mapping)
		return NULL;
3054 3055 3056 3057 3058 3059 3060

	/*
	 * 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();
3061
	p = radix_tree_lookup(&mapping->page_tree, i);
3062
	rcu_read_unlock();
3063

3064 3065 3066
	return p;
}

3067
static inline unsigned long num_extent_pages(u64 start, u64 len)
3068
{
3069 3070
	return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
		(start >> PAGE_CACHE_SHIFT);
3071 3072
}

3073 3074 3075 3076 3077 3078
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;
3079
#if LEAK_DEBUG
3080
	unsigned long flags;
C
Chris Mason 已提交
3081
#endif
3082 3083 3084 3085

	eb = kmem_cache_zalloc(extent_buffer_cache, mask);
	eb->start = start;
	eb->len = len;
3086 3087 3088
	spin_lock_init(&eb->lock);
	init_waitqueue_head(&eb->lock_wq);

3089
#if LEAK_DEBUG
3090 3091 3092
	spin_lock_irqsave(&leak_lock, flags);
	list_add(&eb->leak_list, &buffers);
	spin_unlock_irqrestore(&leak_lock, flags);
C
Chris Mason 已提交
3093
#endif
3094 3095 3096 3097 3098 3099 3100
	atomic_set(&eb->refs, 1);

	return eb;
}

static void __free_extent_buffer(struct extent_buffer *eb)
{
3101
#if LEAK_DEBUG
3102 3103 3104 3105
	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
3106
#endif
3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118
	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;
3119
	struct extent_buffer *exists = NULL;
3120 3121 3122 3123
	struct page *p;
	struct address_space *mapping = tree->mapping;
	int uptodate = 1;

3124 3125 3126 3127 3128
	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
3129
		mark_page_accessed(eb->first_page);
3130 3131 3132 3133
		return eb;
	}
	spin_unlock(&tree->buffer_lock);

3134
	eb = __alloc_extent_buffer(tree, start, len, mask);
3135
	if (!eb)
3136 3137 3138 3139 3140 3141 3142 3143 3144 3145
		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);
3146
		uptodate = PageUptodate(page0);
3147 3148 3149 3150 3151 3152 3153
	} else {
		i = 0;
	}
	for (; i < num_pages; i++, index++) {
		p = find_or_create_page(mapping, index, mask | __GFP_HIGHMEM);
		if (!p) {
			WARN_ON(1);
3154
			goto free_eb;
3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168
		}
		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)
3169
		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3170

3171 3172 3173 3174 3175 3176 3177 3178 3179 3180
	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;
	}
	/* add one reference for the tree */
	atomic_inc(&eb->refs);
3181
	spin_unlock(&tree->buffer_lock);
3182 3183
	return eb;

3184
free_eb:
3185
	if (!atomic_dec_and_test(&eb->refs))
3186 3187
		return exists;
	for (index = 1; index < i; index++)
3188
		page_cache_release(extent_buffer_page(eb, index));
3189
	page_cache_release(extent_buffer_page(eb, 0));
3190
	__free_extent_buffer(eb);
3191
	return exists;
3192 3193 3194 3195 3196 3197 3198 3199
}

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

3200 3201 3202 3203 3204
	spin_lock(&tree->buffer_lock);
	eb = buffer_search(tree, start);
	if (eb)
		atomic_inc(&eb->refs);
	spin_unlock(&tree->buffer_lock);
3205

J
Josef Bacik 已提交
3206 3207 3208
	if (eb)
		mark_page_accessed(eb->first_page);

3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219
	return eb;
}

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

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

3220
	WARN_ON(1);
3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233
}

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);
3234
		if (!PageDirty(page))
C
Chris Mason 已提交
3235 3236
			continue;

3237
		lock_page(page);
3238 3239 3240 3241 3242 3243
		if (i == 0)
			set_page_extent_head(page, eb->len);
		else
			set_page_private(page, EXTENT_PAGE_PRIVATE);

		clear_page_dirty_for_io(page);
3244
		spin_lock_irq(&page->mapping->tree_lock);
3245 3246 3247 3248 3249
		if (!PageDirty(page)) {
			radix_tree_tag_clear(&page->mapping->page_tree,
						page_index(page),
						PAGECACHE_TAG_DIRTY);
		}
3250
		spin_unlock_irq(&page->mapping->tree_lock);
3251
		unlock_page(page);
3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267
	}
	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;
3268
	int was_dirty = 0;
3269

3270
	was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
3271
	num_pages = num_extent_pages(eb->start, eb->len);
3272
	for (i = 0; i < num_pages; i++)
3273
		__set_page_dirty_nobuffers(extent_buffer_page(eb, i));
3274
	return was_dirty;
3275 3276
}

3277
int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
3278 3279
				struct extent_buffer *eb,
				struct extent_state **cached_state)
3280 3281 3282 3283 3284 3285
{
	unsigned long i;
	struct page *page;
	unsigned long num_pages;

	num_pages = num_extent_pages(eb->start, eb->len);
3286
	clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3287 3288

	clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
3289
			      cached_state, GFP_NOFS);
3290 3291
	for (i = 0; i < num_pages; i++) {
		page = extent_buffer_page(eb, i);
C
Chris Mason 已提交
3292 3293
		if (page)
			ClearPageUptodate(page);
3294 3295 3296 3297
	}
	return 0;
}

3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321
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;
}

3322 3323 3324 3325 3326 3327 3328 3329 3330
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;

3331
	ret = test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL);
3332 3333
	if (ret)
		return 1;
C
Chris Mason 已提交
3334
	while (start <= end) {
3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347
		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;
}

3348
int extent_buffer_uptodate(struct extent_io_tree *tree,
3349 3350
			   struct extent_buffer *eb,
			   struct extent_state *cached_state)
3351
{
3352
	int ret = 0;
3353 3354
	unsigned long num_pages;
	unsigned long i;
3355 3356 3357
	struct page *page;
	int pg_uptodate = 1;

3358
	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
C
Chris Mason 已提交
3359
		return 1;
3360

C
Chris Mason 已提交
3361
	ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3362
			   EXTENT_UPTODATE, 1, cached_state);
C
Chris Mason 已提交
3363 3364
	if (ret)
		return ret;
3365 3366 3367 3368 3369 3370 3371 3372 3373

	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
3374
	return pg_uptodate;
3375 3376 3377 3378
}

int read_extent_buffer_pages(struct extent_io_tree *tree,
			     struct extent_buffer *eb,
3379
			     u64 start, int wait,
3380
			     get_extent_t *get_extent, int mirror_num)
3381 3382 3383 3384 3385 3386
{
	unsigned long i;
	unsigned long start_i;
	struct page *page;
	int err;
	int ret = 0;
3387 3388 3389
	int locked_pages = 0;
	int all_uptodate = 1;
	int inc_all_pages = 0;
3390
	unsigned long num_pages;
3391
	struct bio *bio = NULL;
C
Chris Mason 已提交
3392
	unsigned long bio_flags = 0;
3393

3394
	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
3395 3396
		return 0;

3397
	if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
3398
			   EXTENT_UPTODATE, 1, NULL)) {
3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413
		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) {
3414
			if (!trylock_page(page))
3415
				goto unlock_exit;
3416 3417 3418
		} else {
			lock_page(page);
		}
3419
		locked_pages++;
C
Chris Mason 已提交
3420
		if (!PageUptodate(page))
3421 3422 3423 3424
			all_uptodate = 0;
	}
	if (all_uptodate) {
		if (start_i == 0)
3425
			set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3426 3427 3428 3429 3430 3431 3432 3433 3434 3435
		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;
3436
			ClearPageError(page);
3437
			err = __extent_read_full_page(tree, page,
3438
						      get_extent, &bio,
C
Chris Mason 已提交
3439
						      mirror_num, &bio_flags);
C
Chris Mason 已提交
3440
			if (err)
3441 3442 3443 3444 3445 3446
				ret = err;
		} else {
			unlock_page(page);
		}
	}

3447
	if (bio)
C
Chris Mason 已提交
3448
		submit_one_bio(READ, bio, mirror_num, bio_flags);
3449

C
Chris Mason 已提交
3450
	if (ret || !wait)
3451
		return ret;
C
Chris Mason 已提交
3452

3453 3454 3455
	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
3456
		if (!PageUptodate(page))
3457 3458
			ret = -EIO;
	}
C
Chris Mason 已提交
3459

3460
	if (!ret)
3461
		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
3462
	return ret;
3463 3464 3465

unlock_exit:
	i = start_i;
C
Chris Mason 已提交
3466
	while (locked_pages > 0) {
3467 3468 3469 3470 3471 3472
		page = extent_buffer_page(eb, i);
		i++;
		unlock_page(page);
		locked_pages--;
	}
	return ret;
3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491
}

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
3492
	while (len > 0) {
3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529
		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
3530

3531
	if (start + min_len > eb->len) {
C
Chris Mason 已提交
3532 3533 3534
		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);
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 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590 3591 3592
		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
3593
	while (len > 0) {
3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 3624 3625 3626 3627
		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
3628
	while (len > 0) {
3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651 3652 3653 3654 3655 3656 3657 3658
		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
3659
	while (len > 0) {
3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690
		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
3691
	while (len > 0) {
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 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754 3755 3756
		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
3757 3758
		printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
		       "len %lu dst len %lu\n", src_offset, len, dst->len);
3759 3760 3761
		BUG_ON(1);
	}
	if (dst_offset + len > dst->len) {
C
Chris Mason 已提交
3762 3763
		printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
		       "len %lu dst len %lu\n", dst_offset, len, dst->len);
3764 3765 3766
		BUG_ON(1);
	}

C
Chris Mason 已提交
3767
	while (len > 0) {
3768 3769 3770 3771 3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803
		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
3804 3805
		printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
		       "len %lu len %lu\n", src_offset, len, dst->len);
3806 3807 3808
		BUG_ON(1);
	}
	if (dst_offset + len > dst->len) {
C
Chris Mason 已提交
3809 3810
		printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
		       "len %lu len %lu\n", dst_offset, len, dst->len);
3811 3812 3813 3814 3815 3816
		BUG_ON(1);
	}
	if (dst_offset < src_offset) {
		memcpy_extent_buffer(dst, dst_offset, src_offset, len);
		return;
	}
C
Chris Mason 已提交
3817
	while (len > 0) {
3818 3819 3820 3821 3822 3823 3824 3825 3826 3827 3828 3829 3830 3831 3832 3833 3834 3835 3836 3837
		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;
	}
}
3838 3839 3840 3841 3842 3843 3844 3845 3846 3847 3848 3849 3850 3851 3852 3853 3854 3855

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;
	}
3856 3857 3858 3859
	if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
		ret = 0;
		goto out;
	}
3860 3861
	/* 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
3862 3863
	for (i = 0; i < num_pages; i++)
		page_cache_release(extent_buffer_page(eb, i));
3864 3865 3866 3867 3868 3869
	rb_erase(&eb->rb_node, &tree->buffer);
	__free_extent_buffer(eb);
out:
	spin_unlock(&tree->buffer_lock);
	return ret;
}