blob: 70c2369f4c52c9176b66d2961fb56cea272654b8 [file] [log] [blame]
#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/bio.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/page-flags.h>
#include <linux/spinlock.h>
#include <linux/blkdev.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/pagevec.h>
#include <linux/prefetch.h>
#include <linux/cleancache.h>
#include "extent_io.h"
#include "extent_map.h"
#include "compat.h"
#include "ctree.h"
#include "btrfs_inode.h"
#include "volumes.h"
#include "check-integrity.h"
#include "locking.h"
#include "rcu-string.h"
static struct kmem_cache *extent_state_cache;
static struct kmem_cache *extent_buffer_cache;
static struct bio_set *btrfs_bioset;
#ifdef CONFIG_BTRFS_DEBUG
static LIST_HEAD(buffers);
static LIST_HEAD(states);
static DEFINE_SPINLOCK(leak_lock);
static inline
void btrfs_leak_debug_add(struct list_head *new, struct list_head *head)
{
unsigned long flags;
spin_lock_irqsave(&leak_lock, flags);
list_add(new, head);
spin_unlock_irqrestore(&leak_lock, flags);
}
static inline
void btrfs_leak_debug_del(struct list_head *entry)
{
unsigned long flags;
spin_lock_irqsave(&leak_lock, flags);
list_del(entry);
spin_unlock_irqrestore(&leak_lock, flags);
}
static inline
void btrfs_leak_debug_check(void)
{
struct extent_state *state;
struct extent_buffer *eb;
while (!list_empty(&states)) {
state = list_entry(states.next, struct extent_state, leak_list);
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));
list_del(&state->leak_list);
kmem_cache_free(extent_state_cache, state);
}
while (!list_empty(&buffers)) {
eb = list_entry(buffers.next, struct extent_buffer, leak_list);
printk(KERN_ERR "btrfs buffer leak start %llu len %lu "
"refs %d\n", (unsigned long long)eb->start,
eb->len, atomic_read(&eb->refs));
list_del(&eb->leak_list);
kmem_cache_free(extent_buffer_cache, eb);
}
}
#else
#define btrfs_leak_debug_add(new, head) do {} while (0)
#define btrfs_leak_debug_del(entry) do {} while (0)
#define btrfs_leak_debug_check() do {} while (0)
#endif
#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;
unsigned long bio_flags;
/* tells writepage not to lock the state bits for this range
* it still does the unlocking
*/
unsigned int extent_locked:1;
/* tells the submit_bio code to use a WRITE_SYNC */
unsigned int sync_io:1;
};
static noinline void flush_write_bio(void *data);
static inline struct btrfs_fs_info *
tree_fs_info(struct extent_io_tree *tree)
{
return btrfs_sb(tree->mapping->host->i_sb);
}
int __init extent_io_init(void)
{
extent_state_cache = kmem_cache_create("btrfs_extent_state",
sizeof(struct extent_state), 0,
SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
if (!extent_state_cache)
return -ENOMEM;
extent_buffer_cache = kmem_cache_create("btrfs_extent_buffer",
sizeof(struct extent_buffer), 0,
SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
if (!extent_buffer_cache)
goto free_state_cache;
btrfs_bioset = bioset_create(BIO_POOL_SIZE,
offsetof(struct btrfs_io_bio, bio));
if (!btrfs_bioset)
goto free_buffer_cache;
return 0;
free_buffer_cache:
kmem_cache_destroy(extent_buffer_cache);
extent_buffer_cache = NULL;
free_state_cache:
kmem_cache_destroy(extent_state_cache);
extent_state_cache = NULL;
return -ENOMEM;
}
void extent_io_exit(void)
{
btrfs_leak_debug_check();
/*
* Make sure all delayed rcu free are flushed before we
* destroy caches.
*/
rcu_barrier();
if (extent_state_cache)
kmem_cache_destroy(extent_state_cache);
if (extent_buffer_cache)
kmem_cache_destroy(extent_buffer_cache);
if (btrfs_bioset)
bioset_free(btrfs_bioset);
}
void extent_io_tree_init(struct extent_io_tree *tree,
struct address_space *mapping)
{
tree->state = RB_ROOT;
INIT_RADIX_TREE(&tree->buffer, GFP_ATOMIC);
tree->ops = NULL;
tree->dirty_bytes = 0;
spin_lock_init(&tree->lock);
spin_lock_init(&tree->buffer_lock);
tree->mapping = mapping;
}
static struct extent_state *alloc_extent_state(gfp_t mask)
{
struct extent_state *state;
state = kmem_cache_alloc(extent_state_cache, mask);
if (!state)
return state;
state->state = 0;
state->private = 0;
state->tree = NULL;
btrfs_leak_debug_add(&state->leak_list, &states);
atomic_set(&state->refs, 1);
init_waitqueue_head(&state->wq);
trace_alloc_extent_state(state, mask, _RET_IP_);
return state;
}
void free_extent_state(struct extent_state *state)
{
if (!state)
return;
if (atomic_dec_and_test(&state->refs)) {
WARN_ON(state->tree);
btrfs_leak_debug_del(&state->leak_list);
trace_free_extent_state(state, _RET_IP_);
kmem_cache_free(extent_state_cache, state);
}
}
static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
struct rb_node *node)
{
struct rb_node **p = &root->rb_node;
struct rb_node *parent = NULL;
struct tree_entry *entry;
while (*p) {
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;
}
rb_link_node(node, parent, p);
rb_insert_color(node, root);
return NULL;
}
static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
struct rb_node **prev_ret,
struct rb_node **next_ret)
{
struct rb_root *root = &tree->state;
struct rb_node *n = root->rb_node;
struct rb_node *prev = NULL;
struct rb_node *orig_prev = NULL;
struct tree_entry *entry;
struct tree_entry *prev_entry = NULL;
while (n) {
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;
else
return n;
}
if (prev_ret) {
orig_prev = prev;
while (prev && offset > prev_entry->end) {
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);
while (prev && offset < prev_entry->start) {
prev = rb_prev(prev);
prev_entry = rb_entry(prev, struct tree_entry, rb_node);
}
*next_ret = prev;
}
return NULL;
}
static inline struct rb_node *tree_search(struct extent_io_tree *tree,
u64 offset)
{
struct rb_node *prev = NULL;
struct rb_node *ret;
ret = __etree_search(tree, offset, &prev, NULL);
if (!ret)
return prev;
return ret;
}
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);
}
/*
* 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 void merge_state(struct extent_io_tree *tree,
struct extent_state *state)
{
struct extent_state *other;
struct rb_node *other_node;
if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
return;
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) {
merge_cb(tree, state, other);
state->start = other->start;
other->tree = NULL;
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) {
merge_cb(tree, state, other);
state->end = other->end;
other->tree = NULL;
rb_erase(&other->rb_node, &tree->state);
free_extent_state(other);
}
}
}
static void set_state_cb(struct extent_io_tree *tree,
struct extent_state *state, unsigned long *bits)
{
if (tree->ops && tree->ops->set_bit_hook)
tree->ops->set_bit_hook(tree->mapping->host, state, bits);
}
static void clear_state_cb(struct extent_io_tree *tree,
struct extent_state *state, unsigned long *bits)
{
if (tree->ops && tree->ops->clear_bit_hook)
tree->ops->clear_bit_hook(tree->mapping->host, state, bits);
}
static void set_state_bits(struct extent_io_tree *tree,
struct extent_state *state, unsigned long *bits);
/*
* 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,
unsigned long *bits)
{
struct rb_node *node;
if (end < start)
WARN(1, KERN_ERR "btrfs end < start %llu %llu\n",
(unsigned long long)end,
(unsigned long long)start);
state->start = start;
state->end = end;
set_state_bits(tree, state, bits);
node = tree_insert(&tree->state, end, &state->rb_node);
if (node) {
struct extent_state *found;
found = rb_entry(node, struct extent_state, rb_node);
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);
return -EEXIST;
}
state->tree = tree;
merge_state(tree, state);
return 0;
}
static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
u64 split)
{
if (tree->ops && tree->ops->split_extent_hook)
tree->ops->split_extent_hook(tree->mapping->host, orig, split);
}
/*
* 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;
split_cb(tree, orig, split);
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;
}
prealloc->tree = tree;
return 0;
}
static struct extent_state *next_state(struct extent_state *state)
{
struct rb_node *next = rb_next(&state->rb_node);
if (next)
return rb_entry(next, struct extent_state, rb_node);
else
return NULL;
}
/*
* utility function to clear some bits in an extent state struct.
* it will optionally wake up any one waiting on this state (wake == 1).
*
* If no bits are set on the state struct after clearing things, the
* struct is freed and removed from the tree
*/
static struct extent_state *clear_state_bit(struct extent_io_tree *tree,
struct extent_state *state,
unsigned long *bits, int wake)
{
struct extent_state *next;
unsigned long bits_to_clear = *bits & ~EXTENT_CTLBITS;
if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
u64 range = state->end - state->start + 1;
WARN_ON(range > tree->dirty_bytes);
tree->dirty_bytes -= range;
}
clear_state_cb(tree, state, bits);
state->state &= ~bits_to_clear;
if (wake)
wake_up(&state->wq);
if (state->state == 0) {
next = next_state(state);
if (state->tree) {
rb_erase(&state->rb_node, &tree->state);
state->tree = NULL;
free_extent_state(state);
} else {
WARN_ON(1);
}
} else {
merge_state(tree, state);
next = next_state(state);
}
return next;
}
static struct extent_state *
alloc_extent_state_atomic(struct extent_state *prealloc)
{
if (!prealloc)
prealloc = alloc_extent_state(GFP_ATOMIC);
return prealloc;
}
static void extent_io_tree_panic(struct extent_io_tree *tree, int err)
{
btrfs_panic(tree_fs_info(tree), err, "Locking error: "
"Extent tree was modified by another "
"thread while locked.");
}
/*
* 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 success and < 0 on error.
*/
int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
unsigned long bits, int wake, int delete,
struct extent_state **cached_state,
gfp_t mask)
{
struct extent_state *state;
struct extent_state *cached;
struct extent_state *prealloc = NULL;
struct rb_node *node;
u64 last_end;
int err;
int clear = 0;
if (delete)
bits |= ~EXTENT_CTLBITS;
bits |= EXTENT_FIRST_DELALLOC;
if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY))
clear = 1;
again:
if (!prealloc && (mask & __GFP_WAIT)) {
prealloc = alloc_extent_state(mask);
if (!prealloc)
return -ENOMEM;
}
spin_lock(&tree->lock);
if (cached_state) {
cached = *cached_state;
if (clear) {
*cached_state = NULL;
cached_state = NULL;
}
if (cached && cached->tree && cached->start <= start &&
cached->end > start) {
if (clear)
atomic_dec(&cached->refs);
state = cached;
goto hit_next;
}
if (clear)
free_extent_state(cached);
}
/*
* this search will find the extents that end after
* our range starts
*/
node = tree_search(tree, start);
if (!node)
goto out;
state = rb_entry(node, struct extent_state, rb_node);
hit_next:
if (state->start > end)
goto out;
WARN_ON(state->end < start);
last_end = state->end;
/* the state doesn't have the wanted bits, go ahead */
if (!(state->state & bits)) {
state = next_state(state);
goto next;
}
/*
* | ---- 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) {
prealloc = alloc_extent_state_atomic(prealloc);
BUG_ON(!prealloc);
err = split_state(tree, state, prealloc, start);
if (err)
extent_io_tree_panic(tree, err);
prealloc = NULL;
if (err)
goto out;
if (state->end <= end) {
state = clear_state_bit(tree, state, &bits, wake);
goto next;
}
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) {
prealloc = alloc_extent_state_atomic(prealloc);
BUG_ON(!prealloc);
err = split_state(tree, state, prealloc, end + 1);
if (err)
extent_io_tree_panic(tree, err);
if (wake)
wake_up(&state->wq);
clear_state_bit(tree, prealloc, &bits, wake);
prealloc = NULL;
goto out;
}
state = clear_state_bit(tree, state, &bits, wake);
next:
if (last_end == (u64)-1)
goto out;
start = last_end + 1;
if (start <= end && state && !need_resched())
goto hit_next;
goto search_again;
out:
spin_unlock(&tree->lock);
if (prealloc)
free_extent_state(prealloc);
return 0;
search_again:
if (start > end)
goto out;
spin_unlock(&tree->lock);
if (mask & __GFP_WAIT)
cond_resched();
goto again;
}
static void wait_on_state(struct extent_io_tree *tree,
struct extent_state *state)
__releases(tree->lock)
__acquires(tree->lock)
{
DEFINE_WAIT(wait);
prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
spin_unlock(&tree->lock);
schedule();
spin_lock(&tree->lock);
finish_wait(&state->wq, &wait);
}
/*
* waits for one or more bits to clear on a range in the state tree.
* The range [start, end] is inclusive.
* The tree lock is taken by this function
*/
static void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
unsigned long bits)
{
struct extent_state *state;
struct rb_node *node;
spin_lock(&tree->lock);
again:
while (1) {
/*
* this search will find all the extents that end after
* our range starts
*/
node = tree_search(tree, start);
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;
cond_resched_lock(&tree->lock);
}
out:
spin_unlock(&tree->lock);
}
static void set_state_bits(struct extent_io_tree *tree,
struct extent_state *state,
unsigned long *bits)
{
unsigned long bits_to_set = *bits & ~EXTENT_CTLBITS;
set_state_cb(tree, state, bits);
if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
u64 range = state->end - state->start + 1;
tree->dirty_bytes += range;
}
state->state |= bits_to_set;
}
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);
}
}
}
static void uncache_state(struct extent_state **cached_ptr)
{
if (cached_ptr && (*cached_ptr)) {
struct extent_state *state = *cached_ptr;
*cached_ptr = NULL;
free_extent_state(state);
}
}
/*
* 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.
*
* 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.
*
* [start, end] is inclusive This takes the tree lock.
*/
static int __must_check
__set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
unsigned long bits, unsigned long exclusive_bits,
u64 *failed_start, struct extent_state **cached_state,
gfp_t mask)
{
struct extent_state *state;
struct extent_state *prealloc = NULL;
struct rb_node *node;
int err = 0;
u64 last_start;
u64 last_end;
bits |= EXTENT_FIRST_DELALLOC;
again:
if (!prealloc && (mask & __GFP_WAIT)) {
prealloc = alloc_extent_state(mask);
BUG_ON(!prealloc);
}
spin_lock(&tree->lock);
if (cached_state && *cached_state) {
state = *cached_state;
if (state->start <= start && state->end > start &&
state->tree) {
node = &state->rb_node;
goto hit_next;
}
}
/*
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search(tree, start);
if (!node) {
prealloc = alloc_extent_state_atomic(prealloc);
BUG_ON(!prealloc);
err = insert_state(tree, prealloc, start, end, &bits);
if (err)
extent_io_tree_panic(tree, err);
prealloc = NULL;
goto out;
}
state = rb_entry(node, struct extent_state, rb_node);
hit_next:
last_start = state->start;
last_end = state->end;
/*
* | ---- desired range ---- |
* | state |
*
* Just lock what we found and keep going
*/
if (state->start == start && state->end <= end) {
if (state->state & exclusive_bits) {
*failed_start = state->start;
err = -EEXIST;
goto out;
}
set_state_bits(tree, state, &bits);
cache_state(state, cached_state);
merge_state(tree, state);
if (last_end == (u64)-1)
goto out;
start = last_end + 1;
state = next_state(state);
if (start < end && state && state->start == start &&
!need_resched())
goto hit_next;
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) {
if (state->state & exclusive_bits) {
*failed_start = start;
err = -EEXIST;
goto out;
}
prealloc = alloc_extent_state_atomic(prealloc);
BUG_ON(!prealloc);
err = split_state(tree, state, prealloc, start);
if (err)
extent_io_tree_panic(tree, err);
prealloc = NULL;
if (err)
goto out;
if (state->end <= end) {
set_state_bits(tree, state, &bits);
cache_state(state, cached_state);
merge_state(tree, state);
if (last_end == (u64)-1)
goto out;
start = last_end + 1;
state = next_state(state);
if (start < end && state && state->start == start &&
!need_resched())
goto hit_next;
}
goto search_again;
}
/*
* | ---- desired range ---- |
* | state | or | state |
*
* There's a hole, we need to insert something in it and
* ignore the extent we found.
*/
if (state->start > start) {
u64 this_end;
if (end < last_start)
this_end = end;
else
this_end = last_start - 1;
prealloc = alloc_extent_state_atomic(prealloc);
BUG_ON(!prealloc);
/*
* Avoid to free 'prealloc' if it can be merged with
* the later extent.
*/
err = insert_state(tree, prealloc, start, this_end,
&bits);
if (err)
extent_io_tree_panic(tree, err);
cache_state(prealloc, cached_state);
prealloc = NULL;
start = this_end + 1;
goto search_again;
}
/*
* | ---- desired range ---- |
* | state |
* We need to split the extent, and set the bit
* on the first half
*/
if (state->start <= end && state->end > end) {
if (state->state & exclusive_bits) {
*failed_start = start;
err = -EEXIST;
goto out;
}
prealloc = alloc_extent_state_atomic(prealloc);
BUG_ON(!prealloc);
err = split_state(tree, state, prealloc, end + 1);
if (err)
extent_io_tree_panic(tree, err);
set_state_bits(tree, prealloc, &bits);
cache_state(prealloc, cached_state);
merge_state(tree, prealloc);
prealloc = NULL;
goto out;
}
goto search_again;
out:
spin_unlock(&tree->lock);
if (prealloc)
free_extent_state(prealloc);
return err;
search_again:
if (start > end)
goto out;
spin_unlock(&tree->lock);
if (mask & __GFP_WAIT)
cond_resched();
goto again;
}
int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
unsigned long bits, u64 * failed_start,
struct extent_state **cached_state, gfp_t mask)
{
return __set_extent_bit(tree, start, end, bits, 0, failed_start,
cached_state, mask);
}
/**
* convert_extent_bit - convert all bits in a given range from one bit to
* another
* @tree: the io tree to search
* @start: the start offset in bytes
* @end: the end offset in bytes (inclusive)
* @bits: the bits to set in this range
* @clear_bits: the bits to clear in this range
* @cached_state: state that we're going to cache
* @mask: the allocation mask
*
* This will go through and set bits for the given range. If any states exist
* already in this range they are set with the given bit and cleared of the
* clear_bits. This is only meant to be used by things that are mergeable, ie
* converting from say DELALLOC to DIRTY. This is not meant to be used with
* boundary bits like LOCK.
*/
int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
unsigned long bits, unsigned long clear_bits,
struct extent_state **cached_state, gfp_t mask)
{
struct extent_state *state;
struct extent_state *prealloc = NULL;
struct rb_node *node;
int err = 0;
u64 last_start;
u64 last_end;
again:
if (!prealloc && (mask & __GFP_WAIT)) {
prealloc = alloc_extent_state(mask);
if (!prealloc)
return -ENOMEM;
}
spin_lock(&tree->lock);
if (cached_state && *cached_state) {
state = *cached_state;
if (state->start <= start && state->end > start &&
state->tree) {
node = &state->rb_node;
goto hit_next;
}
}
/*
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search(tree, start);
if (!node) {
prealloc = alloc_extent_state_atomic(prealloc);
if (!prealloc) {
err = -ENOMEM;
goto out;
}
err = insert_state(tree, prealloc, start, end, &bits);
prealloc = NULL;
if (err)
extent_io_tree_panic(tree, err);
goto out;
}
state = rb_entry(node, struct extent_state, rb_node);
hit_next:
last_start = state->start;
last_end = state->end;
/*
* | ---- desired range ---- |
* | state |
*
* Just lock what we found and keep going
*/
if (state->start == start && state->end <= end) {
set_state_bits(tree, state, &bits);
cache_state(state, cached_state);
state = clear_state_bit(tree, state, &clear_bits, 0);
if (last_end == (u64)-1)
goto out;
start = last_end + 1;
if (start < end && state && state->start == start &&
!need_resched())
goto hit_next;
goto search_again;
}
/*
* | ---- desired range ---- |
* | state |
* or
* | ------------- state -------------- |
*
* We need to split the extent we found, and may flip bits on
* second half.
*
* If the extent we found extends past our
* range, we just split and search again. It'll get split
* again the next time though.
*
* If the extent we found is inside our range, we set the
* desired bit on it.
*/
if (state->start < start) {
prealloc = alloc_extent_state_atomic(prealloc);
if (!prealloc) {
err = -ENOMEM;
goto out;
}
err = split_state(tree, state, prealloc, start);
if (err)
extent_io_tree_panic(tree, err);
prealloc = NULL;
if (err)
goto out;
if (state->end <= end) {
set_state_bits(tree, state, &bits);
cache_state(state, cached_state);
state = clear_state_bit(tree, state, &clear_bits, 0);
if (last_end == (u64)-1)
goto out;
start = last_end + 1;
if (start < end && state && state->start == start &&
!need_resched())
goto hit_next;
}
goto search_again;
}
/*
* | ---- desired range ---- |
* | state | or | state |
*
* There's a hole, we need to insert something in it and
* ignore the extent we found.
*/
if (state->start > start) {
u64 this_end;
if (end < last_start)
this_end = end;
else
this_end = last_start - 1;
prealloc = alloc_extent_state_atomic(prealloc);
if (!prealloc) {
err = -ENOMEM;
goto out;
}
/*
* Avoid to free 'prealloc' if it can be merged with
* the later extent.
*/
err = insert_state(tree, prealloc, start, this_end,
&bits);
if (err)
extent_io_tree_panic(tree, err);
cache_state(prealloc, cached_state);
prealloc = NULL;
start = this_end + 1;
goto search_again;
}
/*
* | ---- desired range ---- |
* | state |
* We need to split the extent, and set the bit
* on the first half
*/
if (state->start <= end && state->end > end) {
prealloc = alloc_extent_state_atomic(prealloc);
if (!prealloc) {
err = -ENOMEM;
goto out;
}
err = split_state(tree, state, prealloc, end + 1);
if (err)
extent_io_tree_panic(tree, err);
set_state_bits(tree, prealloc, &bits);
cache_state(prealloc, cached_state);
clear_state_bit(tree, prealloc, &clear_bits, 0);
prealloc = NULL;
goto out;
}
goto search_again;
out:
spin_unlock(&tree->lock);
if (prealloc)
free_extent_state(prealloc);
return err;
search_again:
if (start > end)
goto out;
spin_unlock(&tree->lock);
if (mask & __GFP_WAIT)
cond_resched();
goto again;
}
/* 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, NULL,
NULL, mask);
}
int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
unsigned long bits, gfp_t mask)
{
return set_extent_bit(tree, start, end, bits, NULL,
NULL, mask);
}
int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
unsigned long bits, gfp_t mask)
{
return clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask);
}
int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
struct extent_state **cached_state, gfp_t mask)
{
return set_extent_bit(tree, start, end,
EXTENT_DELALLOC | EXTENT_UPTODATE,
NULL, cached_state, mask);
}
int set_extent_defrag(struct extent_io_tree *tree, u64 start, u64 end,
struct extent_state **cached_state, gfp_t mask)
{
return set_extent_bit(tree, start, end,
EXTENT_DELALLOC | EXTENT_UPTODATE | EXTENT_DEFRAG,
NULL, cached_state, mask);
}
int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
gfp_t mask)
{
return clear_extent_bit(tree, start, end,
EXTENT_DIRTY | EXTENT_DELALLOC |
EXTENT_DO_ACCOUNTING, 0, 0, NULL, mask);
}
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, NULL,
NULL, mask);
}
int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
struct extent_state **cached_state, gfp_t mask)
{
return set_extent_bit(tree, start, end, EXTENT_UPTODATE, NULL,
cached_state, mask);
}
int clear_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
struct extent_state **cached_state, gfp_t mask)
{
return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
cached_state, mask);
}
/*
* either insert or lock state struct between start and end use mask to tell
* us if waiting is desired.
*/
int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
unsigned long bits, struct extent_state **cached_state)
{
int err;
u64 failed_start;
while (1) {
err = __set_extent_bit(tree, start, end, EXTENT_LOCKED | bits,
EXTENT_LOCKED, &failed_start,
cached_state, GFP_NOFS);
if (err == -EEXIST) {
wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
start = failed_start;
} else
break;
WARN_ON(start > end);
}
return err;
}
int lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
{
return lock_extent_bits(tree, start, end, 0, NULL);
}
int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
{
int err;
u64 failed_start;
err = __set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
&failed_start, NULL, GFP_NOFS);
if (err == -EEXIST) {
if (failed_start > start)
clear_extent_bit(tree, start, failed_start - 1,
EXTENT_LOCKED, 1, 0, NULL, GFP_NOFS);
return 0;
}
return 1;
}
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);
}
int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end)
{
return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
GFP_NOFS);
}
int extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end)
{
unsigned long index = start >> PAGE_CACHE_SHIFT;
unsigned long end_index = end >> PAGE_CACHE_SHIFT;
struct page *page;
while (index <= end_index) {
page = find_get_page(inode->i_mapping, index);
BUG_ON(!page); /* Pages should be in the extent_io_tree */
clear_page_dirty_for_io(page);
page_cache_release(page);
index++;
}
return 0;
}
int extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end)
{
unsigned long index = start >> PAGE_CACHE_SHIFT;
unsigned long end_index = end >> PAGE_CACHE_SHIFT;
struct page *page;
while (index <= end_index) {
page = find_get_page(inode->i_mapping, index);
BUG_ON(!page); /* Pages should be in the extent_io_tree */
account_page_redirty(page);
__set_page_dirty_nobuffers(page);
page_cache_release(page);
index++;
}
return 0;
}
/*
* helper function to set both pages and extents in the tree writeback
*/
static int set_range_writeback(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); /* Pages should be in the extent_io_tree */
set_page_writeback(page);
page_cache_release(page);
index++;
}
return 0;
}
/* 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'
*/
static struct extent_state *
find_first_extent_bit_state(struct extent_io_tree *tree,
u64 start, unsigned long 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);
if (!node)
goto out;
while (1) {
state = rb_entry(node, struct extent_state, rb_node);
if (state->end >= start && (state->state & bits))
return state;
node = rb_next(node);
if (!node)
break;
}
out:
return NULL;
}
/*
* 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. If found something, return 0.
*/
int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
u64 *start_ret, u64 *end_ret, unsigned long bits,
struct extent_state **cached_state)
{
struct extent_state *state;
struct rb_node *n;
int ret = 1;
spin_lock(&tree->lock);
if (cached_state && *cached_state) {
state = *cached_state;
if (state->end == start - 1 && state->tree) {
n = rb_next(&state->rb_node);
while (n) {
state = rb_entry(n, struct extent_state,
rb_node);
if (state->state & bits)
goto got_it;
n = rb_next(n);
}
free_extent_state(*cached_state);
*cached_state = NULL;
goto out;
}
free_extent_state(*cached_state);
*cached_state = NULL;
}
state = find_first_extent_bit_state(tree, start, bits);
got_it:
if (state) {
cache_state(state, cached_state);
*start_ret = state->start;
*end_ret = state->end;
ret = 0;
}
out:
spin_unlock(&tree->lock);
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_delalloc_range(struct extent_io_tree *tree,
u64 *start, u64 *end, u64 max_bytes,
struct extent_state **cached_state)
{
struct rb_node *node;
struct extent_state *state;
u64 cur_start = *start;
u64 found = 0;
u64 total_bytes = 0;
spin_lock(&tree->lock);
/*
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search(tree, cur_start);
if (!node) {
if (!found)
*end = (u64)-1;
goto out;
}
while (1) {
state = rb_entry(node, struct extent_state, rb_node);
if (found && (state->start != cur_start ||
(state->state & EXTENT_BOUNDARY))) {
goto out;
}
if (!(state->state & EXTENT_DELALLOC)) {
if (!found)
*end = state->end;
goto out;
}
if (!found) {
*start = state->start;
*cached_state = state;
atomic_inc(&state->refs);
}
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:
spin_unlock(&tree->lock);
return found;
}
static noinline void __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;
while (nr_pages > 0) {
ret = find_get_pages_contig(inode->i_mapping, index,
min_t(unsigned long, nr_pages,
ARRAY_SIZE(pages)), pages);
for (i = 0; i < ret; i++) {
if (pages[i] != locked_page)
unlock_page(pages[i]);
page_cache_release(pages[i]);
}
nr_pages -= ret;
index += ret;
cond_resched();
}
}
static noinline int lock_delalloc_pages(struct inode *inode,
struct page *locked_page,
u64 delalloc_start,
u64 delalloc_end)
{
unsigned long index = delalloc_start >> PAGE_CACHE_SHIFT;
unsigned long start_index = index;
unsigned long end_index = delalloc_end >> PAGE_CACHE_SHIFT;
unsigned long pages_locked = 0;
struct page *pages[16];
unsigned long nrpages;
int ret;
int i;
/* the caller is responsible for locking the start index */
if (index == locked_page->index && index == end_index)
return 0;
/* skip the page at the start index */
nrpages = end_index - index + 1;
while (nrpages > 0) {
ret = find_get_pages_contig(inode->i_mapping, index,
min_t(unsigned long,
nrpages, ARRAY_SIZE(pages)), pages);
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
*/
if (pages[i] != locked_page) {
lock_page(pages[i]);
if (!PageDirty(pages[i]) ||
pages[i]->mapping != inode->i_mapping) {
ret = -EAGAIN;
unlock_page(pages[i]);
page_cache_release(pages[i]);
goto done;
}
}
page_cache_release(pages[i]);
pages_locked++;
}
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;
struct extent_state *cached_state = NULL;
int ret;
int loops = 0;
again:
/* step one, find a bunch of delalloc bytes starting at start */
delalloc_start = *start;
delalloc_end = 0;
found = find_delalloc_range(tree, &delalloc_start, &delalloc_end,
max_bytes, &cached_state);
if (!found || delalloc_end <= *start) {
*start = delalloc_start;
*end = delalloc_end;
free_extent_state(cached_state);
return found;
}
/*
* 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
*/
if (delalloc_start < *start)
delalloc_start = *start;
/*
* make sure to limit the number of pages we try to lock down
* if we're looping.
*/
if (delalloc_end + 1 - delalloc_start > max_bytes && loops)
delalloc_end = delalloc_start + PAGE_CACHE_SIZE - 1;
/* 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
*/
free_extent_state(cached_state);
cached_state = NULL;
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); /* Only valid values are 0 and -EAGAIN */
/* step three, lock the state bits for the whole range */
lock_extent_bits(tree, delalloc_start, delalloc_end, 0, &cached_state);
/* then test to make sure it is all still delalloc */
ret = test_range_bit(tree, delalloc_start, delalloc_end,
EXTENT_DELALLOC, 1, cached_state);
if (!ret) {
unlock_extent_cached(tree, delalloc_start, delalloc_end,
&cached_state, GFP_NOFS);
__unlock_for_delalloc(inode, locked_page,
delalloc_start, delalloc_end);
cond_resched();
goto again;
}
free_extent_state(cached_state);
*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,
unsigned long op)
{
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;
unsigned long clear_bits = 0;
if (op & EXTENT_CLEAR_UNLOCK)
clear_bits |= EXTENT_LOCKED;
if (op & EXTENT_CLEAR_DIRTY)
clear_bits |= EXTENT_DIRTY;
if (op & EXTENT_CLEAR_DELALLOC)
clear_bits |= EXTENT_DELALLOC;
clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
if (!(op & (EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK |
EXTENT_SET_PRIVATE2)))
return 0;
while (nr_pages > 0) {
ret = find_get_pages_contig(inode->i_mapping, index,
min_t(unsigned long,
nr_pages, ARRAY_SIZE(pages)), pages);
for (i = 0; i < ret; i++) {
if (op & EXTENT_SET_PRIVATE2)
SetPagePrivate2(pages[i]);
if (pages[i] == locked_page) {
page_cache_release(pages[i]);
continue;
}
if (op & EXTENT_CLEAR_DIRTY)
clear_page_dirty_for_io(pages[i]);
if (op & EXTENT_SET_WRITEBACK)
set_page_writeback(pages[i]);
if (op & EXTENT_END_WRITEBACK)
end_page_writeback(pages[i]);
if (op & EXTENT_CLEAR_UNLOCK_PAGE)
unlock_page(pages[i]);
page_cache_release(pages[i]);
}
nr_pages -= ret;
index += ret;
cond_resched();
}
return 0;
}
/*
* 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.
*/
u64 count_range_bits(struct extent_io_tree *tree,
u64 *start, u64 search_end, u64 max_bytes,
unsigned long bits, int contig)
{
struct rb_node *node;
struct extent_state *state;
u64 cur_start = *start;
u64 total_bytes = 0;
u64 last = 0;
int found = 0;
if (search_end <= cur_start) {
WARN_ON(1);
return 0;
}
spin_lock(&tree->lock);
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.
*/
node = tree_search(tree, cur_start);
if (!node)
goto out;
while (1) {
state = rb_entry(node, struct extent_state, rb_node);
if (state->start > search_end)
break;
if (contig && found && state->start > last + 1)
break;
if (state->end >= cur_start && (state->state & bits) == bits) {
total_bytes += min(search_end, state->end) + 1 -
max(cur_start, state->start);
if (total_bytes >= max_bytes)
break;
if (!found) {
*start = max(cur_start, state->start);
found = 1;
}
last = state->end;
} else if (contig && found) {
break;
}
node = rb_next(node);
if (!node)
break;
}
out:
spin_unlock(&tree->lock);
return total_bytes;
}
/*
* set the private field for a given byte offset in the tree. If there isn't
* an extent_state there already, this does nothing.
*/
int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
{
struct rb_node *node;
struct extent_state *state;
int ret = 0;
spin_lock(&tree->lock);
/*
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search(tree, start);
if (!node) {
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:
spin_unlock(&tree->lock);
return ret;
}
void extent_cache_csums_dio(struct extent_io_tree *tree, u64 start, u32 csums[],
int count)
{
struct rb_node *node;
struct extent_state *state;
spin_lock(&tree->lock);
/*
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search(tree, start);
BUG_ON(!node);
state = rb_entry(node, struct extent_state, rb_node);
BUG_ON(state->start != start);
while (count) {
state->private = *csums++;
count--;
state = next_state(state);
}
spin_unlock(&tree->lock);
}
static inline u64 __btrfs_get_bio_offset(struct bio *bio, int bio_index)
{
struct bio_vec *bvec = bio->bi_io_vec + bio_index;
return page_offset(bvec->bv_page) + bvec->bv_offset;
}
void extent_cache_csums(struct extent_io_tree *tree, struct bio *bio, int bio_index,
u32 csums[], int count)
{
struct rb_node *node;
struct extent_state *state = NULL;
u64 start;
spin_lock(&tree->lock);
do {
start = __btrfs_get_bio_offset(bio, bio_index);
if (state == NULL || state->start != start) {
node = tree_search(tree, start);
BUG_ON(!node);
state = rb_entry(node, struct extent_state, rb_node);
BUG_ON(state->start != start);
}
state->private = *csums++;
count--;
bio_index++;
state = next_state(state);
} while (count);
spin_unlock(&tree->lock);
}
int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
{
struct rb_node *node;
struct extent_state *state;
int ret = 0;
spin_lock(&tree->lock);
/*
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search(tree, start);
if (!node) {
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:
spin_unlock(&tree->lock);
return ret;
}
/*
* searches a range in the state tree for a given mask.
* If 'filled' == 1, this returns 1 only if every extent in the tree
* 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,
unsigned long bits, int filled, struct extent_state *cached)
{
struct extent_state *state = NULL;
struct rb_node *node;
int bitset = 0;
spin_lock(&tree->lock);
if (cached && cached->tree && cached->start <= start &&
cached->end > start)
node = &cached->rb_node;
else
node = tree_search(tree, start);
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;
}
if (state->end == (u64)-1)
break;
start = state->end + 1;
if (start > end)
break;
node = rb_next(node);
if (!node) {
if (filled)
bitset = 0;
break;
}
}
spin_unlock(&tree->lock);
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 void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
{
u64 start = page_offset(page);
u64 end = start + PAGE_CACHE_SIZE - 1;
if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
SetPageUptodate(page);
}
/*
* When IO fails, either with EIO or csum verification fails, we
* try other mirrors that might have a good copy of the data. This
* io_failure_record is used to record state as we go through all the
* mirrors. If another mirror has good data, the page is set up to date
* and things continue. If a good mirror can't be found, the original
* bio end_io callback is called to indicate things have failed.
*/
struct io_failure_record {
struct page *page;
u64 start;
u64 len;
u64 logical;
unsigned long bio_flags;
int this_mirror;
int failed_mirror;
int in_validation;
};
static int free_io_failure(struct inode *inode, struct io_failure_record *rec,
int did_repair)
{
int ret;
int err = 0;
struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
set_state_private(failure_tree, rec->start, 0);
ret = clear_extent_bits(failure_tree, rec->start,
rec->start + rec->len - 1,
EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
if (ret)
err = ret;
ret = clear_extent_bits(&BTRFS_I(inode)->io_tree, rec->start,
rec->start + rec->len - 1,
EXTENT_DAMAGED, GFP_NOFS);
if (ret && !err)
err = ret;
kfree(rec);
return err;
}
static void repair_io_failure_callback(struct bio *bio, int err)
{
complete(bio->bi_private);
}
/*
* this bypasses the standard btrfs submit functions deliberately, as
* the standard behavior is to write all copies in a raid setup. here we only
* want to write the one bad copy. so we do the mapping for ourselves and issue
* submit_bio directly.
* to avoid any synchronization issues, wait for the data after writing, which
* actually prevents the read that triggered the error from finishing.
* currently, there can be no more than two copies of every data bit. thus,
* exactly one rewrite is required.
*/
int repair_io_failure(struct btrfs_fs_info *fs_info, u64 start,
u64 length, u64 logical, struct page *page,
int mirror_num)
{
struct bio *bio;
struct btrfs_device *dev;
DECLARE_COMPLETION_ONSTACK(compl);
u64 map_length = 0;
u64 sector;
struct btrfs_bio *bbio = NULL;
struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
int ret;
BUG_ON(!mirror_num);
/* we can't repair anything in raid56 yet */
if (btrfs_is_parity_mirror(map_tree, logical, length, mirror_num))
return 0;
bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
if (!bio)
return -EIO;
bio->bi_private = &compl;
bio->bi_end_io = repair_io_failure_callback;
bio->bi_size = 0;
map_length = length;
ret = btrfs_map_block(fs_info, WRITE, logical,
&map_length, &bbio, mirror_num);
if (ret) {
bio_put(bio);
return -EIO;
}
BUG_ON(mirror_num != bbio->mirror_num);
sector = bbio->stripes[mirror_num-1].physical >> 9;
bio->bi_sector = sector;
dev = bbio->stripes[mirror_num-1].dev;
kfree(bbio);
if (!dev || !dev->bdev || !dev->writeable) {
bio_put(bio);
return -EIO;
}
bio->bi_bdev = dev->bdev;
bio_add_page(bio, page, length, start - page_offset(page));
btrfsic_submit_bio(WRITE_SYNC, bio);
wait_for_completion(&compl);
if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
/* try to remap that extent elsewhere? */
bio_put(bio);
btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
return -EIO;
}
printk_ratelimited_in_rcu(KERN_INFO "btrfs read error corrected: ino %lu off %llu "
"(dev %s sector %llu)\n", page->mapping->host->i_ino,
start, rcu_str_deref(dev->name), sector);
bio_put(bio);
return 0;
}
int repair_eb_io_failure(struct btrfs_root *root, struct extent_buffer *eb,
int mirror_num)
{
u64 start = eb->start;
unsigned long i, num_pages = num_extent_pages(eb->start, eb->len);
int ret = 0;
for (i = 0; i < num_pages; i++) {
struct page *p = extent_buffer_page(eb, i);
ret = repair_io_failure(root->fs_info, start, PAGE_CACHE_SIZE,
start, p, mirror_num);
if (ret)
break;
start += PAGE_CACHE_SIZE;
}
return ret;
}
/*
* each time an IO finishes, we do a fast check in the IO failure tree
* to see if we need to process or clean up an io_failure_record
*/
static int clean_io_failure(u64 start, struct page *page)
{
u64 private;
u64 private_failure;
struct io_failure_record *failrec;
struct btrfs_fs_info *fs_info;
struct extent_state *state;
int num_copies;
int did_repair = 0;
int ret;
struct inode *inode = page->mapping->host;
private = 0;
ret = count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
(u64)-1, 1, EXTENT_DIRTY, 0);
if (!ret)
return 0;
ret = get_state_private(&BTRFS_I(inode)->io_failure_tree, start,
&private_failure);
if (ret)
return 0;
failrec = (struct io_failure_record *)(unsigned long) private_failure;
BUG_ON(!failrec->this_mirror);
if (failrec->in_validation) {
/* there was no real error, just free the record */
pr_debug("clean_io_failure: freeing dummy error at %llu\n",
failrec->start);
did_repair = 1;
goto out;
}
spin_lock(&BTRFS_I(inode)->io_tree.lock);
state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
failrec->start,
EXTENT_LOCKED);
spin_unlock(&BTRFS_I(inode)->io_tree.lock);
if (state && state->start == failrec->start) {
fs_info = BTRFS_I(inode)->root->fs_info;
num_copies = btrfs_num_copies(fs_info, failrec->logical,
failrec->len);
if (num_copies > 1) {
ret = repair_io_failure(fs_info, start, failrec->len,
failrec->logical, page,
failrec->failed_mirror);
did_repair = !ret;
}
ret = 0;
}
out:
if (!ret)
ret = free_io_failure(inode, failrec, did_repair);
return ret;
}
/*
* this is a generic handler for readpage errors (default
* readpage_io_failed_hook). if other copies exist, read those and write back
* good data to the failed position. does not investigate in remapping the
* failed extent elsewhere, hoping the device will be smart enough to do this as
* needed
*/
static int bio_readpage_error(struct bio *failed_bio, struct page *page,
u64 start, u64 end, int failed_mirror,
struct extent_state *state)
{
struct io_failure_record *failrec = NULL;
u64 private;
struct extent_map *em;
struct inode *inode = page->mapping->host;
struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
struct bio *bio;
int num_copies;
int ret;
int read_mode;
u64 logical;
BUG_ON(failed_bio->bi_rw & REQ_WRITE);
ret = get_state_private(failure_tree, start, &private);
if (ret) {
failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
if (!failrec)
return -ENOMEM;
failrec->start = start;
failrec->len = end - start + 1;
failrec->this_mirror = 0;
failrec->bio_flags = 0;
failrec->in_validation = 0;
read_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, start, failrec->len);
if (!em) {
read_unlock(&em_tree->lock);
kfree(failrec);
return -EIO;
}
if (em->start > start || em->start + em->len < start) {
free_extent_map(em);
em = NULL;
}
read_unlock(&em_tree->lock);
if (!em) {
kfree(failrec);
return -EIO;
}
logical = start - em->start;
logical = em->block_start + logical;
if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
logical = em->block_start;
failrec->bio_flags = EXTENT_BIO_COMPRESSED;
extent_set_compress_type(&failrec->bio_flags,
em->compress_type);
}
pr_debug("bio_readpage_error: (new) logical=%llu, start=%llu, "
"len=%llu\n", logical, start, failrec->len);
failrec->logical = logical;
free_extent_map(em);
/* set the bits in the private failure tree */
ret = set_extent_bits(failure_tree, start, end,
EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
if (ret >= 0)
ret = set_state_private(failure_tree, start,
(u64)(unsigned long)failrec);
/* set the bits in the inode's tree */
if (ret >= 0)
ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED,
GFP_NOFS);
if (ret < 0) {
kfree(failrec);
return ret;
}
} else {
failrec = (struct io_failure_record *)(unsigned long)private;
pr_debug("bio_readpage_error: (found) logical=%llu, "
"start=%llu, len=%llu, validation=%d\n",
failrec->logical, failrec->start, failrec->len,
failrec->in_validation);
/*
* when data can be on disk more than twice, add to failrec here
* (e.g. with a list for failed_mirror) to make
* clean_io_failure() clean all those errors at once.
*/
}
num_copies = btrfs_num_copies(BTRFS_I(inode)->root->fs_info,
failrec->logical, failrec->len);
if (num_copies == 1) {
/*
* we only have a single copy of the data, so don't bother with
* all the retry and error correction code that follows. no
* matter what the error is, it is very likely to persist.
*/
pr_debug("bio_readpage_error: cannot repair, num_copies == 1. "
"state=%p, num_copies=%d, next_mirror %d, "
"failed_mirror %d\n", state, num_copies,
failrec->this_mirror, failed_mirror);
free_io_failure(inode, failrec, 0);
return -EIO;
}
if (!state) {
spin_lock(&tree->lock);
state = find_first_extent_bit_state(tree, failrec->start,
EXTENT_LOCKED);
if (state && state->start != failrec->start)
state = NULL;
spin_unlock(&tree->lock);
}
/*
* there are two premises:
* a) deliver good data to the caller
* b) correct the bad sectors on disk
*/
if (failed_bio->bi_vcnt > 1) {
/*
* to fulfill b), we need to know the exact failing sectors, as
* we don't want to rewrite any more than the failed ones. thus,
* we need separate read requests for the failed bio
*
* if the following BUG_ON triggers, our validation request got
* merged. we need separate requests for our algorithm to work.
*/
BUG_ON(failrec->in_validation);
failrec->in_validation = 1;
failrec->this_mirror = failed_mirror;
read_mode = READ_SYNC | REQ_FAILFAST_DEV;
} else {
/*
* we're ready to fulfill a) and b) alongside. get a good copy
* of the failed sector and if we succeed, we have setup
* everything for repair_io_failure to do the rest for us.
*/
if (failrec->in_validation) {
BUG_ON(failrec->this_mirror != failed_mirror);
failrec->in_validation = 0;
failrec->this_mirror = 0;
}
failrec->failed_mirror = failed_mirror;
failrec->this_mirror++;
if (failrec->this_mirror == failed_mirror)
failrec->this_mirror++;
read_mode = READ_SYNC;
}
if (!state || failrec->this_mirror > num_copies) {
pr_debug("bio_readpage_error: (fail) state=%p, num_copies=%d, "
"next_mirror %d, failed_mirror %d\n", state,
num_copies, failrec->this_mirror, failed_mirror);
free_io_failure(inode, failrec, 0);
return -EIO;
}
bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
if (!bio) {
free_io_failure(inode, failrec, 0);
return -EIO;
}
bio->bi_private = state;
bio->bi_end_io = failed_bio->bi_end_io;
bio->bi_sector = failrec->logical >> 9;
bio->bi_bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
bio->bi_size = 0;
bio_add_page(bio, page, failrec->len, start - page_offset(page));
pr_debug("bio_readpage_error: submitting new read[%#x] to "
"this_mirror=%d, num_copies=%d, in_validation=%d\n", read_mode,
failrec->this_mirror, num_copies, failrec->in_validation);
ret = tree->ops->submit_bio_hook(inode, read_mode, bio,
failrec->this_mirror,
failrec->bio_flags, 0);
return ret;
}
/* lots and lots of room for performance fixes in the end_bio funcs */
int end_extent_writepage(struct page *page, int err, u64 start, u64 end)
{
int uptodate = (err == 0);
struct extent_io_tree *tree;
int ret = 0;
tree = &BTRFS_I(page->mapping->host)->io_tree;
if (tree->ops && tree->ops->writepage_end_io_hook) {
ret = tree->ops->writepage_end_io_hook(page, start,
end, NULL, uptodate);
if (ret)
uptodate = 0;
}
if (!uptodate) {
ClearPageUptodate(page);
SetPageError(page);
ret = ret < 0 ? ret : -EIO;
mapping_set_error(page->mapping, ret);
}
return 0;
}
/*
* 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)
{
struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
struct extent_io_tree *tree;
u64 start;
u64 end;
do {
struct page *page = bvec->bv_page;
tree = &BTRFS_I(page->mapping->host)->io_tree;
/* We always issue full-page reads, but if some block
* in a page fails to read, blk_update_request() will
* advance bv_offset and adjust bv_len to compensate.
* Print a warning for nonzero offsets, and an error
* if they don't add up to a full page. */
if (bvec->bv_offset || bvec->bv_len != PAGE_CACHE_SIZE)
printk("%s page write in btrfs with offset %u and length %u\n",
bvec->bv_offset + bvec->bv_len != PAGE_CACHE_SIZE
? KERN_ERR "partial" : KERN_INFO "incomplete",
bvec->bv_offset, bvec->bv_len);
start = page_offset(page);
end = start + bvec->bv_offset + bvec->bv_len - 1;
if (--bvec >= bio->bi_io_vec)
prefetchw(&bvec->bv_page->flags);
if (end_extent_writepage(page, err, start, end))
continue;
end_page_writeback(page);
} while (bvec >= bio->bi_io_vec);
bio_put(bio);
}
/*
* after a readpage IO is done, we need to:
* clear the uptodate bits on error
* set the uptodate bits if things worked
* set the page up to date if all extents in the tree are uptodate
* clear the lock bit in the extent tree
* unlock the page if there are no other extents locked for it
*
* Scheduling is not allowed, so the extent state tree is expected
* to have one and only one object corresponding to this IO.
*/
static void end_bio_extent_readpage(struct bio *bio, int err)
{
int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
struct bio_vec *bvec = bio->bi_io_vec;
struct extent_io_tree *tree;
u64 start;
u64 end;
int mirror;
int ret;
if (err)
uptodate = 0;
do {
struct page *page = bvec->bv_page;
struct extent_state *cached = NULL;
struct extent_state *state;
struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
pr_debug("end_bio_extent_readpage: bi_sector=%llu, err=%d, "
"mirror=%lu\n", (u64)bio->bi_sector, err,
io_bio->mirror_num);
tree = &BTRFS_I(page->mapping->host)->io_tree;
/* We always issue full-page reads, but if some block
* in a page fails to read, blk_update_request() will
* advance bv_offset and adjust bv_len to compensate.
* Print a warning for nonzero offsets, and an error
* if they don't add up to a full page. */
if (bvec->bv_offset || bvec->bv_len != PAGE_CACHE_SIZE)
printk("%s page read in btrfs with offset %u and length %u\n",
bvec->bv_offset + bvec->bv_len != PAGE_CACHE_SIZE
? KERN_ERR "partial" : KERN_INFO "incomplete",
bvec->bv_offset, bvec->bv_len);
start = page_offset(page);
end = start + bvec->bv_offset + bvec->bv_len - 1;
if (++bvec <= bvec_end)
prefetchw(&bvec->bv_page->flags);
spin_lock(&tree->lock);
state = find_first_extent_bit_state(tree, start, EXTENT_LOCKED);
if (state && state->start == start) {
/*
* take a reference on the state, unlock will drop
* the ref
*/
cache_state(state, &cached);
}
spin_unlock(&tree->lock);
mirror = io_bio->mirror_num;
if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
ret = tree->ops->readpage_end_io_hook(page, start, end,
state, mirror);
if (ret)
uptodate = 0;
else
clean_io_failure(start, page);
}
if (!uptodate && tree->ops && tree->ops->readpage_io_failed_hook) {
ret = tree->ops->readpage_io_failed_hook(page, mirror);
if (!ret && !err &&
test_bit(BIO_UPTODATE, &bio->bi_flags))
uptodate = 1;
} else if (!uptodate) {
/*
* The generic bio_readpage_error handles errors the
* following way: If possible, new read requests are
* created and submitted and will end up in
* end_bio_extent_readpage as well (if we're lucky, not
* in the !uptodate case). In that case it returns 0 and
* we just go on with the next page in our bio. If it
* can't handle the error it will return -EIO and we
* remain responsible for that page.
*/
ret = bio_readpage_error(bio, page, start, end, mirror, NULL);
if (ret == 0) {
uptodate =
test_bit(BIO_UPTODATE, &bio->bi_flags);
if (err)
uptodate = 0;
uncache_state(&cached);
continue;
}
}
if (uptodate && tree->track_uptodate) {
set_extent_uptodate(tree, start, end, &cached,
GFP_ATOMIC);
}
unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
if (uptodate) {
SetPageUptodate(page);
} else {
ClearPageUptodate(page);
SetPageError(page);
}
unlock_page(page);
} while (bvec <= bvec_end);
bio_put(bio);
}
/*
* this allocates from the btrfs_bioset. We're returning a bio right now
* but you can call btrfs_io_bio for the appropriate container_of magic
*/
struct bio *
btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
gfp_t gfp_flags)
{
struct bio *bio;
bio = bio_alloc_bioset(gfp_flags, nr_vecs, btrfs_bioset);
if (bio == NULL && (current->flags & PF_MEMALLOC)) {
while (!bio && (nr_vecs /= 2)) {
bio = bio_alloc_bioset(gfp_flags,
nr_vecs, btrfs_bioset);
}
}
if (bio) {
bio->bi_size = 0;
bio->bi_bdev = bdev;
bio->bi_sector = first_sector;
}
return bio;
}
struct bio *btrfs_bio_clone(struct bio *bio, gfp_t gfp_mask)
{
return bio_clone_bioset(bio, gfp_mask, btrfs_bioset);
}
/* this also allocates from the btrfs_bioset */
struct bio *btrfs_io_bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
{
return bio_alloc_bioset(gfp_mask, nr_iovecs, btrfs_bioset);
}
static int __must_check submit_one_bio(int rw, struct bio *bio,
int mirror_num, unsigned long bio_flags)
{
int ret = 0;
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;
start = page_offset(page) + bvec->bv_offset;
bio->bi_private = NULL;
bio_get(bio);
if (tree->ops && tree->ops->submit_bio_hook)
ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio,
mirror_num, bio_flags, start);
else
btrfsic_submit_bio(rw, bio);
if (bio_flagged(bio, BIO_EOPNOTSUPP))
ret = -EOPNOTSUPP;
bio_put(bio);
return ret;
}
static int merge_bio(int rw, struct extent_io_tree *tree, struct page *page,
unsigned long offset, size_t size, struct bio *bio,
unsigned long bio_flags)
{
int ret = 0;
if (tree->ops && tree->ops->merge_bio_hook)
ret = tree->ops->merge_bio_hook(rw, page, offset, size, bio,
bio_flags);
BUG_ON(ret < 0);
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,
bio_end_io_t end_io_func,
int mirror_num,
unsigned long prev_bio_flags,
unsigned long bio_flags)
{
int ret = 0;
struct bio *bio;
int nr;
int contig = 0;
int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
if (bio_ret && *bio_ret) {
bio = *bio_ret;
if (old_compressed)
contig = bio->bi_sector == sector;
else
contig = bio_end_sector(bio) == sector;
if (prev_bio_flags != bio_flags || !contig ||
merge_bio(rw, tree, 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);
if (ret < 0)
return ret;
bio = NULL;
} else {
return 0;
}
}
if (this_compressed)
nr = BIO_MAX_PAGES;
else
nr = bio_get_nr_vecs(bdev);
bio = btrfs_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
if (!bio)
return -ENOMEM;
bio_add_page(bio, page, page_size, offset);
bio->bi_end_io = end_io_func;
bio->bi_private = tree;
if (bio_ret)
*bio_ret = bio;
else
ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
return ret;
}
static void attach_extent_buffer_page(struct extent_buffer *eb,
struct page *page)
{
if (!PagePrivate(page)) {
SetPagePrivate(page);
page_cache_get(page);
set_page_private(page, (unsigned long)eb);
} else {
WARN_ON(page->private != (unsigned long)eb);
}
}
void set_page_extent_mapped(struct page *page)
{
if (!PagePrivate(page)) {
SetPagePrivate(page);
page_cache_get(page);
set_page_private(page, EXTENT_PAGE_PRIVATE);
}
}
/*
* 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)
* XXX JDM: This needs looking at to ensure proper page locking
*/
static int __extent_read_full_page(struct extent_io_tree *tree,
struct page *page,
get_extent_t *get_extent,
struct bio **bio, int mirror_num,
unsigned long *bio_flags, int rw)
{
struct inode *inode = page->mapping->host;
u64 start = page_offset(page);
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;
struct btrfs_ordered_extent *ordered;
int ret;
int nr = 0;
size_t pg_offset = 0;
size_t iosize;
size_t disk_io_size;
size_t blocksize = inode->i_sb->s_blocksize;
unsigned long this_bio_flag = 0;
set_page_extent_mapped(page);
if (!PageUptodate(page)) {
if (cleancache_get_page(page) == 0) {
BUG_ON(blocksize != PAGE_SIZE);
goto out;
}
}
end = page_end;
while (1) {
lock_extent(tree, start, end);
ordered = btrfs_lookup_ordered_extent(inode, start);
if (!ordered)
break;
unlock_extent(tree, start, end);
btrfs_start_ordered_extent(inode, ordered, 1);
btrfs_put_ordered_extent(ordered);
}
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);
memset(userpage + zero_offset, 0, iosize);
flush_dcache_page(page);
kunmap_atomic(userpage);