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linux/fs/btrfs/extent_io.c
Josef Bacik 41a2ee75aa btrfs: introduce per-inode file extent tree 
In order to keep track of where we have file extents on disk, and thus
where it is safe to adjust the i_size to, we need to have a tree in
place to keep track of the contiguous areas we have file extents for.

Add helpers to use this tree, as it's not required for NO_HOLES file
systems.  We will use this by setting DIRTY for areas we know we have
file extent item's set, and clearing it when we remove file extent items
for truncation.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-03-23 17:01:24 +01:00

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// SPDX-License-Identifier: GPL-2.0
#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-io-tree.h"
#include "extent_map.h"
#include "ctree.h"
#include "btrfs_inode.h"
#include "volumes.h"
#include "check-integrity.h"
#include "locking.h"
#include "rcu-string.h"
#include "backref.h"
#include "disk-io.h"
static struct kmem_cache *extent_state_cache;
static struct kmem_cache *extent_buffer_cache;
static struct bio_set btrfs_bioset;
static inline bool extent_state_in_tree(const struct extent_state *state)
{
return !RB_EMPTY_NODE(&state->rb_node);
}
#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_extent_buffer_leak_debug_check(void)
{
struct extent_buffer *eb;
while (!list_empty(&buffers)) {
eb = list_entry(buffers.next, struct extent_buffer, leak_list);
pr_err("BTRFS: buffer leak start %llu len %lu refs %d bflags %lu\n",
eb->start, eb->len, atomic_read(&eb->refs), eb->bflags);
list_del(&eb->leak_list);
kmem_cache_free(extent_buffer_cache, eb);
}
}
static inline void btrfs_extent_state_leak_debug_check(void)
{
struct extent_state *state;
while (!list_empty(&states)) {
state = list_entry(states.next, struct extent_state, leak_list);
pr_err("BTRFS: state leak: start %llu end %llu state %u in tree %d refs %d\n",
state->start, state->end, state->state,
extent_state_in_tree(state),
refcount_read(&state->refs));
list_del(&state->leak_list);
kmem_cache_free(extent_state_cache, state);
}
}
#define btrfs_debug_check_extent_io_range(tree, start, end) \
__btrfs_debug_check_extent_io_range(__func__, (tree), (start), (end))
static inline void __btrfs_debug_check_extent_io_range(const char *caller,
struct extent_io_tree *tree, u64 start, u64 end)
{
struct inode *inode = tree->private_data;
u64 isize;
if (!inode || !is_data_inode(inode))
return;
isize = i_size_read(inode);
if (end >= PAGE_SIZE && (end % 2) == 0 && end != isize - 1) {
btrfs_debug_rl(BTRFS_I(inode)->root->fs_info,
"%s: ino %llu isize %llu odd range [%llu,%llu]",
caller, btrfs_ino(BTRFS_I(inode)), isize, start, end);
}
}
#else
#define btrfs_leak_debug_add(new, head) do {} while (0)
#define btrfs_leak_debug_del(entry) do {} while (0)
#define btrfs_extent_buffer_leak_debug_check() do {} while (0)
#define btrfs_extent_state_leak_debug_check() do {} while (0)
#define btrfs_debug_check_extent_io_range(c, s, e) do {} while (0)
#endif
struct tree_entry {
u64 start;
u64 end;
struct rb_node rb_node;
};
struct extent_page_data {
struct bio *bio;
struct extent_io_tree *tree;
/* 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 REQ_SYNC */
unsigned int sync_io:1;
};
static int add_extent_changeset(struct extent_state *state, unsigned bits,
struct extent_changeset *changeset,
int set)
{
int ret;
if (!changeset)
return 0;
if (set && (state->state & bits) == bits)
return 0;
if (!set && (state->state & bits) == 0)
return 0;
changeset->bytes_changed += state->end - state->start + 1;
ret = ulist_add(&changeset->range_changed, state->start, state->end,
GFP_ATOMIC);
return ret;
}
static int __must_check submit_one_bio(struct bio *bio, int mirror_num,
unsigned long bio_flags)
{
blk_status_t ret = 0;
struct extent_io_tree *tree = bio->bi_private;
bio->bi_private = NULL;
if (tree->ops)
ret = tree->ops->submit_bio_hook(tree->private_data, bio,
mirror_num, bio_flags);
else
btrfsic_submit_bio(bio);
return blk_status_to_errno(ret);
}
/* Cleanup unsubmitted bios */
static void end_write_bio(struct extent_page_data *epd, int ret)
{
if (epd->bio) {
epd->bio->bi_status = errno_to_blk_status(ret);
bio_endio(epd->bio);
epd->bio = NULL;
}
}
/*
* Submit bio from extent page data via submit_one_bio
*
* Return 0 if everything is OK.
* Return <0 for error.
*/
static int __must_check flush_write_bio(struct extent_page_data *epd)
{
int ret = 0;
if (epd->bio) {
ret = submit_one_bio(epd->bio, 0, 0);
/*
* Clean up of epd->bio is handled by its endio function.
* And endio is either triggered by successful bio execution
* or the error handler of submit bio hook.
* So at this point, no matter what happened, we don't need
* to clean up epd->bio.
*/
epd->bio = NULL;
}
return ret;
}
int __init extent_state_cache_init(void)
{
extent_state_cache = kmem_cache_create("btrfs_extent_state",
sizeof(struct extent_state), 0,
SLAB_MEM_SPREAD, NULL);
if (!extent_state_cache)
return -ENOMEM;
return 0;
}
int __init extent_io_init(void)
{
extent_buffer_cache = kmem_cache_create("btrfs_extent_buffer",
sizeof(struct extent_buffer), 0,
SLAB_MEM_SPREAD, NULL);
if (!extent_buffer_cache)
return -ENOMEM;
if (bioset_init(&btrfs_bioset, BIO_POOL_SIZE,
offsetof(struct btrfs_io_bio, bio),
BIOSET_NEED_BVECS))
goto free_buffer_cache;
if (bioset_integrity_create(&btrfs_bioset, BIO_POOL_SIZE))
goto free_bioset;
return 0;
free_bioset:
bioset_exit(&btrfs_bioset);
free_buffer_cache:
kmem_cache_destroy(extent_buffer_cache);
extent_buffer_cache = NULL;
return -ENOMEM;
}
void __cold extent_state_cache_exit(void)
{
btrfs_extent_state_leak_debug_check();
kmem_cache_destroy(extent_state_cache);
}
void __cold extent_io_exit(void)
{
btrfs_extent_buffer_leak_debug_check();
/*
* Make sure all delayed rcu free are flushed before we
* destroy caches.
*/
rcu_barrier();
kmem_cache_destroy(extent_buffer_cache);
bioset_exit(&btrfs_bioset);
}
/*
* For the file_extent_tree, we want to hold the inode lock when we lookup and
* update the disk_i_size, but lockdep will complain because our io_tree we hold
* the tree lock and get the inode lock when setting delalloc. These two things
* are unrelated, so make a class for the file_extent_tree so we don't get the
* two locking patterns mixed up.
*/
static struct lock_class_key file_extent_tree_class;
void extent_io_tree_init(struct btrfs_fs_info *fs_info,
struct extent_io_tree *tree, unsigned int owner,
void *private_data)
{
tree->fs_info = fs_info;
tree->state = RB_ROOT;
tree->ops = NULL;
tree->dirty_bytes = 0;
spin_lock_init(&tree->lock);
tree->private_data = private_data;
tree->owner = owner;
if (owner == IO_TREE_INODE_FILE_EXTENT)
lockdep_set_class(&tree->lock, &file_extent_tree_class);
}
void extent_io_tree_release(struct extent_io_tree *tree)
{
spin_lock(&tree->lock);
/*
* Do a single barrier for the waitqueue_active check here, the state
* of the waitqueue should not change once extent_io_tree_release is
* called.
*/
smp_mb();
while (!RB_EMPTY_ROOT(&tree->state)) {
struct rb_node *node;
struct extent_state *state;
node = rb_first(&tree->state);
state = rb_entry(node, struct extent_state, rb_node);
rb_erase(&state->rb_node, &tree->state);
RB_CLEAR_NODE(&state->rb_node);
/*
* btree io trees aren't supposed to have tasks waiting for
* changes in the flags of extent states ever.
*/
ASSERT(!waitqueue_active(&state->wq));
free_extent_state(state);
cond_resched_lock(&tree->lock);
}
spin_unlock(&tree->lock);
}
static struct extent_state *alloc_extent_state(gfp_t mask)
{
struct extent_state *state;
/*
* The given mask might be not appropriate for the slab allocator,
* drop the unsupported bits
*/
mask &= ~(__GFP_DMA32|__GFP_HIGHMEM);
state = kmem_cache_alloc(extent_state_cache, mask);
if (!state)
return state;
state->state = 0;
state->failrec = NULL;
RB_CLEAR_NODE(&state->rb_node);
btrfs_leak_debug_add(&state->leak_list, &states);
refcount_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 (refcount_dec_and_test(&state->refs)) {
WARN_ON(extent_state_in_tree(state));
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,
struct rb_node *search_start,
u64 offset,
struct rb_node *node,
struct rb_node ***p_in,
struct rb_node **parent_in)
{
struct rb_node **p;
struct rb_node *parent = NULL;
struct tree_entry *entry;
if (p_in && parent_in) {
p = *p_in;
parent = *parent_in;
goto do_insert;
}
p = search_start ? &search_start : &root->rb_node;
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;
}
do_insert:
rb_link_node(node, parent, p);
rb_insert_color(node, root);
return NULL;
}
/**
* __etree_search - searche @tree for an entry that contains @offset. Such
* entry would have entry->start <= offset && entry->end >= offset.
*
* @tree - the tree to search
* @offset - offset that should fall within an entry in @tree
* @next_ret - pointer to the first entry whose range ends after @offset
* @prev - pointer to the first entry whose range begins before @offset
* @p_ret - pointer where new node should be anchored (used when inserting an
* entry in the tree)
* @parent_ret - points to entry which would have been the parent of the entry,
* containing @offset
*
* This function returns a pointer to the entry that contains @offset byte
* address. If no such entry exists, then NULL is returned and the other
* pointer arguments to the function are filled, otherwise the found entry is
* returned and other pointers are left untouched.
*/
static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
struct rb_node **next_ret,
struct rb_node **prev_ret,
struct rb_node ***p_ret,
struct rb_node **parent_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) {
prev = *n;
entry = rb_entry(prev, struct tree_entry, rb_node);
prev_entry = entry;
if (offset < entry->start)
n = &(*n)->rb_left;
else if (offset > entry->end)
n = &(*n)->rb_right;
else
return *n;
}
if (p_ret)
*p_ret = n;
if (parent_ret)
*parent_ret = prev;
if (next_ret) {
orig_prev = prev;
while (prev && offset > prev_entry->end) {
prev = rb_next(prev);
prev_entry = rb_entry(prev, struct tree_entry, rb_node);
}
*next_ret = prev;
prev = orig_prev;
}
if (prev_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);
}
*prev_ret = prev;
}
return NULL;
}
static inline struct rb_node *
tree_search_for_insert(struct extent_io_tree *tree,
u64 offset,
struct rb_node ***p_ret,
struct rb_node **parent_ret)
{
struct rb_node *next= NULL;
struct rb_node *ret;
ret = __etree_search(tree, offset, &next, NULL, p_ret, parent_ret);
if (!ret)
return next;
return ret;
}
static inline struct rb_node *tree_search(struct extent_io_tree *tree,
u64 offset)
{
return tree_search_for_insert(tree, offset, NULL, NULL);
}
/*
* 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_LOCKED | 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) {
if (tree->private_data &&
is_data_inode(tree->private_data))
btrfs_merge_delalloc_extent(tree->private_data,
state, other);
state->start = other->start;
rb_erase(&other->rb_node, &tree->state);
RB_CLEAR_NODE(&other->rb_node);
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) {
if (tree->private_data &&
is_data_inode(tree->private_data))
btrfs_merge_delalloc_extent(tree->private_data,
state, other);
state->end = other->end;
rb_erase(&other->rb_node, &tree->state);
RB_CLEAR_NODE(&other->rb_node);
free_extent_state(other);
}
}
}
static void set_state_bits(struct extent_io_tree *tree,
struct extent_state *state, unsigned *bits,
struct extent_changeset *changeset);
/*
* 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,
struct rb_node ***p,
struct rb_node **parent,
unsigned *bits, struct extent_changeset *changeset)
{
struct rb_node *node;
if (end < start) {
btrfs_err(tree->fs_info,
"insert state: end < start %llu %llu", end, start);
WARN_ON(1);
}
state->start = start;
state->end = end;
set_state_bits(tree, state, bits, changeset);
node = tree_insert(&tree->state, NULL, end, &state->rb_node, p, parent);
if (node) {
struct extent_state *found;
found = rb_entry(node, struct extent_state, rb_node);
btrfs_err(tree->fs_info,
"found node %llu %llu on insert of %llu %llu",
found->start, found->end, start, end);
return -EEXIST;
}
merge_state(tree, state);
return 0;
}
/*
* 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;
if (tree->private_data && is_data_inode(tree->private_data))
btrfs_split_delalloc_extent(tree->private_data, orig, split);
prealloc->start = orig->start;
prealloc->end = split - 1;
prealloc->state = orig->state;
orig->start = split;
node = tree_insert(&tree->state, &orig->rb_node, prealloc->end,
&prealloc->rb_node, NULL, NULL);
if (node) {
free_extent_state(prealloc);
return -EEXIST;
}
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 anyone 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 *bits, int wake,
struct extent_changeset *changeset)
{
struct extent_state *next;
unsigned bits_to_clear = *bits & ~EXTENT_CTLBITS;
int ret;
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;
}
if (tree->private_data && is_data_inode(tree->private_data))
btrfs_clear_delalloc_extent(tree->private_data, state, bits);
ret = add_extent_changeset(state, bits_to_clear, changeset, 0);
BUG_ON(ret < 0);
state->state &= ~bits_to_clear;
if (wake)
wake_up(&state->wq);
if (state->state == 0) {
next = next_state(state);
if (extent_state_in_tree(state)) {
rb_erase(&state->rb_node, &tree->state);
RB_CLEAR_NODE(&state->rb_node);
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)
{
struct inode *inode = tree->private_data;
btrfs_panic(btrfs_sb(inode->i_sb), 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 bits, int wake, int delete,
struct extent_state **cached_state,
gfp_t mask, struct extent_changeset *changeset)
{
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;
btrfs_debug_check_extent_io_range(tree, start, end);
trace_btrfs_clear_extent_bit(tree, start, end - start + 1, bits);
if (bits & EXTENT_DELALLOC)
bits |= EXTENT_NORESERVE;
if (delete)
bits |= ~EXTENT_CTLBITS;
if (bits & (EXTENT_LOCKED | EXTENT_BOUNDARY))
clear = 1;
again:
if (!prealloc && gfpflags_allow_blocking(mask)) {
/*
* Don't care for allocation failure here because we might end
* up not needing the pre-allocated extent state at all, which
* is the case if we only have in the tree extent states that
* cover our input range and don't cover too any other range.
* If we end up needing a new extent state we allocate it later.
*/
prealloc = alloc_extent_state(mask);
}
spin_lock(&tree->lock);
if (cached_state) {
cached = *cached_state;
if (clear) {
*cached_state = NULL;
cached_state = NULL;
}
if (cached && extent_state_in_tree(cached) &&
cached->start <= start && cached->end > start) {
if (clear)
refcount_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,
changeset);
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, changeset);
prealloc = NULL;
goto out;
}
state = clear_state_bit(tree, state, &bits, wake, changeset);
next:
if (last_end == (u64)-1)
goto out;
start = last_end + 1;
if (start <= end && state && !need_resched())
goto hit_next;
search_again:
if (start > end)
goto out;
spin_unlock(&tree->lock);
if (gfpflags_allow_blocking(mask))
cond_resched();
goto again;
out:
spin_unlock(&tree->lock);
if (prealloc)
free_extent_state(prealloc);
return 0;
}
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;
btrfs_debug_check_extent_io_range(tree, start, end);
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);
process_node:
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;
refcount_inc(&state->refs);
wait_on_state(tree, state);
free_extent_state(state);
goto again;
}
start = state->end + 1;
if (start > end)
break;
if (!cond_resched_lock(&tree->lock)) {
node = rb_next(node);
goto process_node;
}
}
out:
spin_unlock(&tree->lock);
}
static void set_state_bits(struct extent_io_tree *tree,
struct extent_state *state,
unsigned *bits, struct extent_changeset *changeset)
{
unsigned bits_to_set = *bits & ~EXTENT_CTLBITS;
int ret;
if (tree->private_data && is_data_inode(tree->private_data))
btrfs_set_delalloc_extent(tree->private_data, state, bits);
if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
u64 range = state->end - state->start + 1;
tree->dirty_bytes += range;
}
ret = add_extent_changeset(state, bits_to_set, changeset, 1);
BUG_ON(ret < 0);
state->state |= bits_to_set;
}
static void cache_state_if_flags(struct extent_state *state,
struct extent_state **cached_ptr,
unsigned flags)
{
if (cached_ptr && !(*cached_ptr)) {
if (!flags || (state->state & flags)) {
*cached_ptr = state;
refcount_inc(&state->refs);
}
}
}
static void cache_state(struct extent_state *state,
struct extent_state **cached_ptr)
{
return cache_state_if_flags(state, cached_ptr,
EXTENT_LOCKED | EXTENT_BOUNDARY);
}
/*
* 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 bits, unsigned exclusive_bits,
u64 *failed_start, struct extent_state **cached_state,
gfp_t mask, struct extent_changeset *changeset)
{
struct extent_state *state;
struct extent_state *prealloc = NULL;
struct rb_node *node;
struct rb_node **p;
struct rb_node *parent;
int err = 0;
u64 last_start;
u64 last_end;
btrfs_debug_check_extent_io_range(tree, start, end);
trace_btrfs_set_extent_bit(tree, start, end - start + 1, bits);
again:
if (!prealloc && gfpflags_allow_blocking(mask)) {
/*
* Don't care for allocation failure here because we might end
* up not needing the pre-allocated extent state at all, which
* is the case if we only have in the tree extent states that
* cover our input range and don't cover too any other range.
* If we end up needing a new extent state we allocate it later.
*/
prealloc = alloc_extent_state(mask);
}
spin_lock(&tree->lock);
if (cached_state && *cached_state) {
state = *cached_state;
if (state->start <= start && state->end > start &&
extent_state_in_tree(state)) {
node = &state->rb_node;
goto hit_next;
}
}
/*
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search_for_insert(tree, start, &p, &parent);
if (!node) {
prealloc = alloc_extent_state_atomic(prealloc);
BUG_ON(!prealloc);
err = insert_state(tree, prealloc, start, end,
&p, &parent, &bits, changeset);
if (err)
extent_io_tree_panic(tree, err);
cache_state(prealloc, cached_state);
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, changeset);
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, changeset);
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,
NULL, NULL, &bits, changeset);
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, changeset);
cache_state(prealloc, cached_state);
merge_state(tree, prealloc);
prealloc = NULL;
goto out;
}
search_again:
if (start > end)
goto out;
spin_unlock(&tree->lock);
if (gfpflags_allow_blocking(mask))
cond_resched();
goto again;
out:
spin_unlock(&tree->lock);
if (prealloc)
free_extent_state(prealloc);
return err;
}
int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
unsigned 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, NULL);
}
/**
* 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
*
* 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.
*
* All allocations are done with GFP_NOFS.
*/
int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
unsigned bits, unsigned clear_bits,
struct extent_state **cached_state)
{
struct extent_state *state;
struct extent_state *prealloc = NULL;
struct rb_node *node;
struct rb_node **p;
struct rb_node *parent;
int err = 0;
u64 last_start;
u64 last_end;
bool first_iteration = true;
btrfs_debug_check_extent_io_range(tree, start, end);
trace_btrfs_convert_extent_bit(tree, start, end - start + 1, bits,
clear_bits);
again:
if (!prealloc) {
/*
* Best effort, don't worry if extent state allocation fails
* here for the first iteration. We might have a cached state
* that matches exactly the target range, in which case no
* extent state allocations are needed. We'll only know this
* after locking the tree.
*/
prealloc = alloc_extent_state(GFP_NOFS);
if (!prealloc && !first_iteration)
return -ENOMEM;
}
spin_lock(&tree->lock);
if (cached_state && *cached_state) {
state = *cached_state;
if (state->start <= start && state->end > start &&
extent_state_in_tree(state)) {
node = &state->rb_node;
goto hit_next;
}
}
/*
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search_for_insert(tree, start, &p, &parent);
if (!node) {
prealloc = alloc_extent_state_atomic(prealloc);
if (!prealloc) {
err = -ENOMEM;
goto out;
}
err = insert_state(tree, prealloc, start, end,
&p, &parent, &bits, NULL);
if (err)
extent_io_tree_panic(tree, err);
cache_state(prealloc, cached_state);
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) {
set_state_bits(tree, state, &bits, NULL);
cache_state(state, cached_state);
state = clear_state_bit(tree, state, &clear_bits, 0, NULL);
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, NULL);
cache_state(state, cached_state);
state = clear_state_bit(tree, state, &clear_bits, 0,
NULL);
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,
NULL, NULL, &bits, NULL);
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, NULL);
cache_state(prealloc, cached_state);
clear_state_bit(tree, prealloc, &clear_bits, 0, NULL);
prealloc = NULL;
goto out;
}
search_again:
if (start > end)
goto out;
spin_unlock(&tree->lock);
cond_resched();
first_iteration = false;
goto again;
out:
spin_unlock(&tree->lock);
if (prealloc)
free_extent_state(prealloc);
return err;
}
/* wrappers around set/clear extent bit */
int set_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
unsigned bits, struct extent_changeset *changeset)
{
/*
* We don't support EXTENT_LOCKED yet, as current changeset will
* record any bits changed, so for EXTENT_LOCKED case, it will
* either fail with -EEXIST or changeset will record the whole
* range.
*/
BUG_ON(bits & EXTENT_LOCKED);
return __set_extent_bit(tree, start, end, bits, 0, NULL, NULL, GFP_NOFS,
changeset);
}
int set_extent_bits_nowait(struct extent_io_tree *tree, u64 start, u64 end,
unsigned bits)
{
return __set_extent_bit(tree, start, end, bits, 0, NULL, NULL,
GFP_NOWAIT, NULL);
}
int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
unsigned bits, int wake, int delete,
struct extent_state **cached)
{
return __clear_extent_bit(tree, start, end, bits, wake, delete,
cached, GFP_NOFS, NULL);
}
int clear_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
unsigned bits, struct extent_changeset *changeset)
{
/*
* Don't support EXTENT_LOCKED case, same reason as
* set_record_extent_bits().
*/
BUG_ON(bits & EXTENT_LOCKED);
return __clear_extent_bit(tree, start, end, bits, 0, 0, NULL, GFP_NOFS,
changeset);
}
/*
* 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,
struct extent_state **cached_state)
{
int err;
u64 failed_start;
while (1) {
err = __set_extent_bit(tree, start, end, EXTENT_LOCKED,
EXTENT_LOCKED, &failed_start,
cached_state, GFP_NOFS, NULL);
if (err == -EEXIST) {
wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
start = failed_start;
} else
break;
WARN_ON(start > end);
}
return err;
}
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, NULL);
if (err == -EEXIST) {
if (failed_start > start)
clear_extent_bit(tree, start, failed_start - 1,
EXTENT_LOCKED, 1, 0, NULL);
return 0;
}
return 1;
}
void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end)
{
unsigned long index = start >> PAGE_SHIFT;
unsigned long end_index = end >> PAGE_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);
put_page(page);
index++;
}
}
void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end)
{
unsigned long index = start >> PAGE_SHIFT;
unsigned long end_index = end >> PAGE_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 */
__set_page_dirty_nobuffers(page);
account_page_redirty(page);
put_page(page);
index++;
}
}
/* 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 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 bits,
struct extent_state **cached_state)
{
struct extent_state *state;
int ret = 1;
spin_lock(&tree->lock);
if (cached_state && *cached_state) {
state = *cached_state;
if (state->end == start - 1 && extent_state_in_tree(state)) {
while ((state = next_state(state)) != NULL) {
if (state->state & bits)
goto got_it;
}
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_if_flags(state, cached_state, 0);
*start_ret = state->start;
*end_ret = state->end;
ret = 0;
}
out:
spin_unlock(&tree->lock);
return ret;
}
/**
* find_contiguous_extent_bit: find a contiguous area of bits
* @tree - io tree to check
* @start - offset to start the search from
* @start_ret - the first offset we found with the bits set
* @end_ret - the final contiguous range of the bits that were set
* @bits - bits to look for
*
* set_extent_bit and clear_extent_bit can temporarily split contiguous ranges
* to set bits appropriately, and then merge them again. During this time it
* will drop the tree->lock, so use this helper if you want to find the actual
* contiguous area for given bits. We will search to the first bit we find, and
* then walk down the tree until we find a non-contiguous area. The area
* returned will be the full contiguous area with the bits set.
*/
int find_contiguous_extent_bit(struct extent_io_tree *tree, u64 start,
u64 *start_ret, u64 *end_ret, unsigned bits)
{
struct extent_state *state;
int ret = 1;
spin_lock(&tree->lock);
state = find_first_extent_bit_state(tree, start, bits);
if (state) {
*start_ret = state->start;
*end_ret = state->end;
while ((state = next_state(state)) != NULL) {
if (state->start > (*end_ret + 1))
break;
*end_ret = state->end;
}
ret = 0;
}
spin_unlock(&tree->lock);
return ret;
}
/**
* find_first_clear_extent_bit - find the first range that has @bits not set.
* This range could start before @start.
*
* @tree - the tree to search
* @start - the offset at/after which the found extent should start
* @start_ret - records the beginning of the range
* @end_ret - records the end of the range (inclusive)
* @bits - the set of bits which must be unset
*
* Since unallocated range is also considered one which doesn't have the bits
* set it's possible that @end_ret contains -1, this happens in case the range
* spans (last_range_end, end of device]. In this case it's up to the caller to
* trim @end_ret to the appropriate size.
*/
void find_first_clear_extent_bit(struct extent_io_tree *tree, u64 start,
u64 *start_ret, u64 *end_ret, unsigned bits)
{
struct extent_state *state;
struct rb_node *node, *prev = NULL, *next;
spin_lock(&tree->lock);
/* Find first extent with bits cleared */
while (1) {
node = __etree_search(tree, start, &next, &prev, NULL, NULL);
if (!node && !next && !prev) {
/*
* Tree is completely empty, send full range and let
* caller deal with it
*/
*start_ret = 0;
*end_ret = -1;
goto out;
} else if (!node && !next) {
/*
* We are past the last allocated chunk, set start at
* the end of the last extent.
*/
state = rb_entry(prev, struct extent_state, rb_node);
*start_ret = state->end + 1;
*end_ret = -1;
goto out;
} else if (!node) {
node = next;
}
/*
* At this point 'node' either contains 'start' or start is
* before 'node'
*/
state = rb_entry(node, struct extent_state, rb_node);
if (in_range(start, state->start, state->end - state->start + 1)) {
if (state->state & bits) {
/*
* |--range with bits sets--|
* |
* start
*/
start = state->end + 1;
} else {
/*
* 'start' falls within a range that doesn't
* have the bits set, so take its start as
* the beginning of the desired range
*
* |--range with bits cleared----|
* |
* start
*/
*start_ret = state->start;
break;
}
} else {
/*
* |---prev range---|---hole/unset---|---node range---|
* |
* start
*
* or
*
* |---hole/unset--||--first node--|
* 0 |
* start
*/
if (prev) {
state = rb_entry(prev, struct extent_state,
rb_node);
*start_ret = state->end + 1;
} else {
*start_ret = 0;
}
break;
}
}
/*
* Find the longest stretch from start until an entry which has the
* bits set
*/
while (1) {
state = rb_entry(node, struct extent_state, rb_node);
if (state->end >= start && !(state->state & bits)) {
*end_ret = state->end;
} else {
*end_ret = state->start - 1;
break;
}
node = rb_next(node);
if (!node)
break;
}
out:
spin_unlock(&tree->lock);
}
/*
* 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,
*
* true is returned if we find something, false if nothing was in the tree
*/
bool btrfs_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;
bool found = false;
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) {
*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;
refcount_inc(&state->refs);
}
found = true;
*end = state->end;
cur_start = state->end + 1;
node = rb_next(node);
total_bytes += state->end - state->start + 1;
if (total_bytes >= max_bytes)
break;
if (!node)
break;
}
out:
spin_unlock(&tree->lock);
return found;
}
static int __process_pages_contig(struct address_space *mapping,
struct page *locked_page,
pgoff_t start_index, pgoff_t end_index,
unsigned long page_ops, pgoff_t *index_ret);
static noinline void __unlock_for_delalloc(struct inode *inode,
struct page *locked_page,
u64 start, u64 end)
{
unsigned long index = start >> PAGE_SHIFT;
unsigned long end_index = end >> PAGE_SHIFT;
ASSERT(locked_page);
if (index == locked_page->index && end_index == index)
return;
__process_pages_contig(inode->i_mapping, locked_page, index, end_index,
PAGE_UNLOCK, NULL);
}
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_SHIFT;
unsigned long index_ret = index;
unsigned long end_index = delalloc_end >> PAGE_SHIFT;
int ret;
ASSERT(locked_page);
if (index == locked_page->index && index == end_index)
return 0;
ret = __process_pages_contig(inode->i_mapping, locked_page, index,
end_index, PAGE_LOCK, &index_ret);
if (ret == -EAGAIN)
__unlock_for_delalloc(inode, locked_page, delalloc_start,
(u64)index_ret << PAGE_SHIFT);
return ret;
}
/*
* Find and lock a contiguous range of bytes in the file marked as delalloc, no
* more than @max_bytes. @Start and @end are used to return the range,
*
* Return: true if we find something
* false if nothing was in the tree
*/
EXPORT_FOR_TESTS
noinline_for_stack bool find_lock_delalloc_range(struct inode *inode,
struct page *locked_page, u64 *start,
u64 *end)
{
struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
u64 max_bytes = BTRFS_MAX_EXTENT_SIZE;
u64 delalloc_start;
u64 delalloc_end;
bool 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 = btrfs_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 false;
}
/*
* 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 (delalloc_end + 1 - delalloc_start > max_bytes)
delalloc_end = delalloc_start + max_bytes - 1;
/* step two, lock all the pages after the page that has start */
ret = lock_delalloc_pages(inode, locked_page,
delalloc_start, delalloc_end);
ASSERT(!ret || ret == -EAGAIN);
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) {
max_bytes = PAGE_SIZE;
loops = 1;
goto again;
} else {
found = false;
goto out_failed;
}
}
/* step three, lock the state bits for the whole range */
lock_extent_bits(tree, delalloc_start, delalloc_end, &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);
__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;
}
static int __process_pages_contig(struct address_space *mapping,
struct page *locked_page,
pgoff_t start_index, pgoff_t end_index,
unsigned long page_ops, pgoff_t *index_ret)
{
unsigned long nr_pages = end_index - start_index + 1;
unsigned long pages_locked = 0;
pgoff_t index = start_index;
struct page *pages[16];
unsigned ret;
int err = 0;
int i;
if (page_ops & PAGE_LOCK) {
ASSERT(page_ops == PAGE_LOCK);
ASSERT(index_ret && *index_ret == start_index);
}
if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
mapping_set_error(mapping, -EIO);
while (nr_pages > 0) {
ret = find_get_pages_contig(mapping, index,
min_t(unsigned long,
nr_pages, ARRAY_SIZE(pages)), pages);
if (ret == 0) {
/*
* Only if we're going to lock these pages,
* can we find nothing at @index.
*/
ASSERT(page_ops & PAGE_LOCK);
err = -EAGAIN;
goto out;
}
for (i = 0; i < ret; i++) {
if (page_ops & PAGE_SET_PRIVATE2)
SetPagePrivate2(pages[i]);
if (locked_page && pages[i] == locked_page) {
put_page(pages[i]);
pages_locked++;
continue;
}
if (page_ops & PAGE_CLEAR_DIRTY)
clear_page_dirty_for_io(pages[i]);
if (page_ops & PAGE_SET_WRITEBACK)
set_page_writeback(pages[i]);
if (page_ops & PAGE_SET_ERROR)
SetPageError(pages[i]);
if (page_ops & PAGE_END_WRITEBACK)
end_page_writeback(pages[i]);
if (page_ops & PAGE_UNLOCK)
unlock_page(pages[i]);
if (page_ops & PAGE_LOCK) {
lock_page(pages[i]);
if (!PageDirty(pages[i]) ||
pages[i]->mapping != mapping) {
unlock_page(pages[i]);
put_page(pages[i]);
err = -EAGAIN;
goto out;
}
}
put_page(pages[i]);
pages_locked++;
}
nr_pages -= ret;
index += ret;
cond_resched();
}
out:
if (err && index_ret)
*index_ret = start_index + pages_locked - 1;
return err;
}
void extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
struct page *locked_page,
unsigned clear_bits,
unsigned long page_ops)
{
clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, clear_bits, 1, 0,
NULL);
__process_pages_contig(inode->i_mapping, locked_page,
start >> PAGE_SHIFT, end >> PAGE_SHIFT,
page_ops, NULL);
}
/*
* 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 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 (WARN_ON(search_end <= cur_start))
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_failrec(struct extent_io_tree *tree, u64 start,
struct io_failure_record *failrec)
{
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->failrec = failrec;
out:
spin_unlock(&tree->lock);
return ret;
}
int get_state_failrec(struct extent_io_tree *tree, u64 start,
struct io_failure_record **failrec)
{
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;
}
*failrec = state->failrec;
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 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 && extent_state_in_tree(cached) && 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_SIZE - 1;
if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
SetPageUptodate(page);
}
int free_io_failure(struct extent_io_tree *failure_tree,
struct extent_io_tree *io_tree,
struct io_failure_record *rec)
{
int ret;
int err = 0;
set_state_failrec(failure_tree, rec->start, NULL);
ret = clear_extent_bits(failure_tree, rec->start,
rec->start + rec->len - 1,
EXTENT_LOCKED | EXTENT_DIRTY);
if (ret)
err = ret;
ret = clear_extent_bits(io_tree, rec->start,
rec->start + rec->len - 1,
EXTENT_DAMAGED);
if (ret && !err)
err = ret;
kfree(rec);
return err;
}
/*
* this bypasses the standard btrfs submit functions deliberately, as
* the standard behavior is to write all copies in a raid setup. here we only
* want to write the one bad copy. so we do the mapping for ourselves and issue
* submit_bio directly.
* 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 ino, u64 start,
u64 length, u64 logical, struct page *page,
unsigned int pg_offset, int mirror_num)
{
struct bio *bio;
struct btrfs_device *dev;
u64 map_length = 0;
u64 sector;
struct btrfs_bio *bbio = NULL;
int ret;
ASSERT(!(fs_info->sb->s_flags & SB_RDONLY));
BUG_ON(!mirror_num);
bio = btrfs_io_bio_alloc(1);
bio->bi_iter.bi_size = 0;
map_length = length;
/*
* Avoid races with device replace and make sure our bbio has devices
* associated to its stripes that don't go away while we are doing the
* read repair operation.
*/
btrfs_bio_counter_inc_blocked(fs_info);
if (btrfs_is_parity_mirror(fs_info, logical, length)) {
/*
* Note that we don't use BTRFS_MAP_WRITE because it's supposed
* to update all raid stripes, but here we just want to correct
* bad stripe, thus BTRFS_MAP_READ is abused to only get the bad
* stripe's dev and sector.
*/
ret = btrfs_map_block(fs_info, BTRFS_MAP_READ, logical,
&map_length, &bbio, 0);
if (ret) {
btrfs_bio_counter_dec(fs_info);
bio_put(bio);
return -EIO;
}
ASSERT(bbio->mirror_num == 1);
} else {
ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, logical,
&map_length, &bbio, mirror_num);
if (ret) {
btrfs_bio_counter_dec(fs_info);
bio_put(bio);
return -EIO;
}
BUG_ON(mirror_num != bbio->mirror_num);
}
sector = bbio->stripes[bbio->mirror_num - 1].physical >> 9;
bio->bi_iter.bi_sector = sector;
dev = bbio->stripes[bbio->mirror_num - 1].dev;
btrfs_put_bbio(bbio);
if (!dev || !dev->bdev ||
!test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state)) {
btrfs_bio_counter_dec(fs_info);
bio_put(bio);
return -EIO;
}
bio_set_dev(bio, dev->bdev);
bio->bi_opf = REQ_OP_WRITE | REQ_SYNC;
bio_add_page(bio, page, length, pg_offset);
if (btrfsic_submit_bio_wait(bio)) {
/* try to remap that extent elsewhere? */
btrfs_bio_counter_dec(fs_info);
bio_put(bio);
btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
return -EIO;
}
btrfs_info_rl_in_rcu(fs_info,
"read error corrected: ino %llu off %llu (dev %s sector %llu)",
ino, start,
rcu_str_deref(dev->name), sector);
btrfs_bio_counter_dec(fs_info);
bio_put(bio);
return 0;
}
int btrfs_repair_eb_io_failure(struct extent_buffer *eb, int mirror_num)
{
struct btrfs_fs_info *fs_info = eb->fs_info;
u64 start = eb->start;
int i, num_pages = num_extent_pages(eb);
int ret = 0;
if (sb_rdonly(fs_info->sb))
return -EROFS;
for (i = 0; i < num_pages; i++) {
struct page *p = eb->pages[i];
ret = repair_io_failure(fs_info, 0, start, PAGE_SIZE, start, p,
start - page_offset(p), mirror_num);
if (ret)
break;
start += PAGE_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
*/
int clean_io_failure(struct btrfs_fs_info *fs_info,
struct extent_io_tree *failure_tree,
struct extent_io_tree *io_tree, u64 start,
struct page *page, u64 ino, unsigned int pg_offset)
{
u64 private;
struct io_failure_record *failrec;
struct extent_state *state;
int num_copies;
int ret;
private = 0;
ret = count_range_bits(failure_tree, &private, (u64)-1, 1,
EXTENT_DIRTY, 0);
if (!ret)
return 0;
ret = get_state_failrec(failure_tree, start, &failrec);
if (ret)
return 0;
BUG_ON(!failrec->this_mirror);
if (failrec->in_validation) {
/* there was no real error, just free the record */
btrfs_debug(fs_info,
"clean_io_failure: freeing dummy error at %llu",
failrec->start);
goto out;
}
if (sb_rdonly(fs_info->sb))
goto out;
spin_lock(&io_tree->lock);
state = find_first_extent_bit_state(io_tree,
failrec->start,
EXTENT_LOCKED);
spin_unlock(&io_tree->lock);
if (state && state->start <= failrec->start &&
state->end >= failrec->start + failrec->len - 1) {
num_copies = btrfs_num_copies(fs_info, failrec->logical,
failrec->len);
if (num_copies > 1) {
repair_io_failure(fs_info, ino, start, failrec->len,
failrec->logical, page, pg_offset,
failrec->failed_mirror);
}
}
out:
free_io_failure(failure_tree, io_tree, failrec);
return 0;
}
/*
* Can be called when
* - hold extent lock
* - under ordered extent
* - the inode is freeing
*/
void btrfs_free_io_failure_record(struct btrfs_inode *inode, u64 start, u64 end)
{
struct extent_io_tree *failure_tree = &inode->io_failure_tree;
struct io_failure_record *failrec;
struct extent_state *state, *next;
if (RB_EMPTY_ROOT(&failure_tree->state))
return;
spin_lock(&failure_tree->lock);
state = find_first_extent_bit_state(failure_tree, start, EXTENT_DIRTY);
while (state) {
if (state->start > end)
break;
ASSERT(state->end <= end);
next = next_state(state);
failrec = state->failrec;
free_extent_state(state);
kfree(failrec);
state = next;
}
spin_unlock(&failure_tree->lock);
}
int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
struct io_failure_record **failrec_ret)
{
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct io_failure_record *failrec;
struct extent_map *em;
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;
int ret;
u64 logical;
ret = get_state_failrec(failure_tree, start, &failrec);
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);
}
btrfs_debug(fs_info,
"Get IO Failure Record: (new) logical=%llu, start=%llu, len=%llu",
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);
if (ret >= 0)
ret = set_state_failrec(failure_tree, start, failrec);
/* set the bits in the inode's tree */
if (ret >= 0)
ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED);
if (ret < 0) {
kfree(failrec);
return ret;
}
} else {
btrfs_debug(fs_info,
"Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu, validation=%d",
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.
*/
}
*failrec_ret = failrec;
return 0;
}
bool btrfs_check_repairable(struct inode *inode, unsigned failed_bio_pages,
struct io_failure_record *failrec, int failed_mirror)
{
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
int num_copies;
num_copies = btrfs_num_copies(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.
*/
btrfs_debug(fs_info,
"Check Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
num_copies, failrec->this_mirror, failed_mirror);
return false;
}
/*
* there are two premises:
* a) deliver good data to the caller
* b) correct the bad sectors on disk
*/
if (failed_bio_pages > 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;
} 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++;
}
if (failrec->this_mirror > num_copies) {
btrfs_debug(fs_info,
"Check Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
num_copies, failrec->this_mirror, failed_mirror);
return false;
}
return true;
}
struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
struct io_failure_record *failrec,
struct page *page, int pg_offset, int icsum,
bio_end_io_t *endio_func, void *data)
{
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct bio *bio;
struct btrfs_io_bio *btrfs_failed_bio;
struct btrfs_io_bio *btrfs_bio;
bio = btrfs_io_bio_alloc(1);
bio->bi_end_io = endio_func;
bio->bi_iter.bi_sector = failrec->logical >> 9;
bio->bi_iter.bi_size = 0;
bio->bi_private = data;
btrfs_failed_bio = btrfs_io_bio(failed_bio);
if (btrfs_failed_bio->csum) {
u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
btrfs_bio = btrfs_io_bio(bio);
btrfs_bio->csum = btrfs_bio->csum_inline;
icsum *= csum_size;
memcpy(btrfs_bio->csum, btrfs_failed_bio->csum + icsum,
csum_size);
}
bio_add_page(bio, page, failrec->len, pg_offset);
return bio;
}
/*
* This is a generic handler for readpage errors. 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, u64 phy_offset,
struct page *page, u64 start, u64 end,
int failed_mirror)
{
struct io_failure_record *failrec;
struct inode *inode = page->mapping->host;
struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
struct bio *bio;
int read_mode = 0;
blk_status_t status;
int ret;
unsigned failed_bio_pages = failed_bio->bi_iter.bi_size >> PAGE_SHIFT;
BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
if (ret)
return ret;
if (!btrfs_check_repairable(inode, failed_bio_pages, failrec,
failed_mirror)) {
free_io_failure(failure_tree, tree, failrec);
return -EIO;
}
if (failed_bio_pages > 1)
read_mode |= REQ_FAILFAST_DEV;
phy_offset >>= inode->i_sb->s_blocksize_bits;
bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
start - page_offset(page),
(int)phy_offset, failed_bio->bi_end_io,
NULL);
bio->bi_opf = REQ_OP_READ | read_mode;
btrfs_debug(btrfs_sb(inode->i_sb),
"Repair Read Error: submitting new read[%#x] to this_mirror=%d, in_validation=%d",
read_mode, failrec->this_mirror, failrec->in_validation);
status = tree->ops->submit_bio_hook(tree->private_data, bio, failrec->this_mirror,
failrec->bio_flags);
if (status) {
free_io_failure(failure_tree, tree, failrec);
bio_put(bio);
ret = blk_status_to_errno(status);
}
return ret;
}
/* lots and lots of room for performance fixes in the end_bio funcs */
void end_extent_writepage(struct page *page, int err, u64 start, u64 end)
{
int uptodate = (err == 0);
int ret = 0;
btrfs_writepage_endio_finish_ordered(page, start, end, uptodate);
if (!uptodate) {
ClearPageUptodate(page);
SetPageError(page);
ret = err < 0 ? err : -EIO;
mapping_set_error(page->mapping, ret);
}
}
/*
* 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 error = blk_status_to_errno(bio->bi_status);
struct bio_vec *bvec;
u64 start;
u64 end;
struct bvec_iter_all iter_all;
ASSERT(!bio_flagged(bio, BIO_CLONED));
bio_for_each_segment_all(bvec, bio, iter_all) {
struct page *page = bvec->bv_page;
struct inode *inode = page->mapping->host;
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
/* 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_SIZE) {
if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
btrfs_err(fs_info,
"partial page write in btrfs with offset %u and length %u",
bvec->bv_offset, bvec->bv_len);
else
btrfs_info(fs_info,
"incomplete page write in btrfs with offset %u and length %u",
bvec->bv_offset, bvec->bv_len);
}
start = page_offset(page);
end = start + bvec->bv_offset + bvec->bv_len - 1;
end_extent_writepage(page, error, start, end);
end_page_writeback(page);
}
bio_put(bio);
}
static void
endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64 len,
int uptodate)
{
struct extent_state *cached = NULL;
u64 end = start + len - 1;
if (uptodate && tree->track_uptodate)
set_extent_uptodate(tree, start, end, &cached, GFP_ATOMIC);
unlock_extent_cached_atomic(tree, start, end, &cached);
}
/*
* 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)
{
struct bio_vec *bvec;
int uptodate = !bio->bi_status;
struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
struct extent_io_tree *tree, *failure_tree;
u64 offset = 0;
u64 start;
u64 end;
u64 len;
u64 extent_start = 0;
u64 extent_len = 0;
int mirror;
int ret;
struct bvec_iter_all iter_all;
ASSERT(!bio_flagged(bio, BIO_CLONED));
bio_for_each_segment_all(bvec, bio, iter_all) {
struct page *page = bvec->bv_page;
struct inode *inode = page->mapping->host;
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
bool data_inode = btrfs_ino(BTRFS_I(inode))
!= BTRFS_BTREE_INODE_OBJECTID;
btrfs_debug(fs_info,
"end_bio_extent_readpage: bi_sector=%llu, err=%d, mirror=%u",
(u64)bio->bi_iter.bi_sector, bio->bi_status,
io_bio->mirror_num);
tree = &BTRFS_I(inode)->io_tree;
failure_tree = &BTRFS_I(inode)->io_failure_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_SIZE) {
if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
btrfs_err(fs_info,
"partial page read in btrfs with offset %u and length %u",
bvec->bv_offset, bvec->bv_len);
else
btrfs_info(fs_info,
"incomplete page read in btrfs with offset %u and length %u",
bvec->bv_offset, bvec->bv_len);
}
start = page_offset(page);
end = start + bvec->bv_offset + bvec->bv_len - 1;
len = bvec->bv_len;
mirror = io_bio->mirror_num;
if (likely(uptodate)) {
ret = tree->ops->readpage_end_io_hook(io_bio, offset,
page, start, end,
mirror);
if (ret)
uptodate = 0;
else
clean_io_failure(BTRFS_I(inode)->root->fs_info,
failure_tree, tree, start,
page,
btrfs_ino(BTRFS_I(inode)), 0);
}
if (likely(uptodate))
goto readpage_ok;
if (data_inode) {
/*
* 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, offset, page, start, end,
mirror);
if (ret == 0) {
uptodate = !bio->bi_status;
offset += len;
continue;
}
} else {
struct extent_buffer *eb;
eb = (struct extent_buffer *)page->private;
set_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
eb->read_mirror = mirror;
atomic_dec(&eb->io_pages);
if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD,
&eb->bflags))
btree_readahead_hook(eb, -EIO);
}
readpage_ok:
if (likely(uptodate)) {
loff_t i_size = i_size_read(inode);
pgoff_t end_index = i_size >> PAGE_SHIFT;
unsigned off;
/* Zero out the end if this page straddles i_size */
off = offset_in_page(i_size);
if (page->index == end_index && off)
zero_user_segment(page, off, PAGE_SIZE);
SetPageUptodate(page);
} else {
ClearPageUptodate(page);
SetPageError(page);
}
unlock_page(page);
offset += len;
if (unlikely(!uptodate)) {
if (extent_len) {
endio_readpage_release_extent(tree,
extent_start,
extent_len, 1);
extent_start = 0;
extent_len = 0;
}
endio_readpage_release_extent(tree, start,
end - start + 1, 0);
} else if (!extent_len) {
extent_start = start;
extent_len = end + 1 - start;
} else if (extent_start + extent_len == start) {
extent_len += end + 1 - start;
} else {
endio_readpage_release_extent(tree, extent_start,
extent_len, uptodate);
extent_start = start;
extent_len = end + 1 - start;
}
}
if (extent_len)
endio_readpage_release_extent(tree, extent_start, extent_len,
uptodate);
btrfs_io_bio_free_csum(io_bio);
bio_put(bio);
}
/*
* Initialize the members up to but not including 'bio'. Use after allocating a
* new bio by bio_alloc_bioset as it does not initialize the bytes outside of
* 'bio' because use of __GFP_ZERO is not supported.
*/
static inline void btrfs_io_bio_init(struct btrfs_io_bio *btrfs_bio)
{
memset(btrfs_bio, 0, offsetof(struct btrfs_io_bio, bio));
}
/*
* The following helpers allocate a bio. As it's backed by a bioset, it'll
* never fail. 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(u64 first_byte)
{
struct bio *bio;
bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_PAGES, &btrfs_bioset);
bio->bi_iter.bi_sector = first_byte >> 9;
btrfs_io_bio_init(btrfs_io_bio(bio));
return bio;
}
struct bio *btrfs_bio_clone(struct bio *bio)
{
struct btrfs_io_bio *btrfs_bio;
struct bio *new;
/* Bio allocation backed by a bioset does not fail */
new = bio_clone_fast(bio, GFP_NOFS, &btrfs_bioset);
btrfs_bio = btrfs_io_bio(new);
btrfs_io_bio_init(btrfs_bio);
btrfs_bio->iter = bio->bi_iter;
return new;
}
struct bio *btrfs_io_bio_alloc(unsigned int nr_iovecs)
{
struct bio *bio;
/* Bio allocation backed by a bioset does not fail */
bio = bio_alloc_bioset(GFP_NOFS, nr_iovecs, &btrfs_bioset);
btrfs_io_bio_init(btrfs_io_bio(bio));
return bio;
}
struct bio *btrfs_bio_clone_partial(struct bio *orig, int offset, int size)
{
struct bio *bio;
struct btrfs_io_bio *btrfs_bio;
/* this will never fail when it's backed by a bioset */
bio = bio_clone_fast(orig, GFP_NOFS, &btrfs_bioset);
ASSERT(bio);
btrfs_bio = btrfs_io_bio(bio);
btrfs_io_bio_init(btrfs_bio);
bio_trim(bio, offset >> 9, size >> 9);
btrfs_bio->iter = bio->bi_iter;
return bio;
}
/*
* @opf: bio REQ_OP_* and REQ_* flags as one value
* @tree: tree so we can call our merge_bio hook
* @wbc: optional writeback control for io accounting
* @page: page to add to the bio
* @pg_offset: offset of the new bio or to check whether we are adding
* a contiguous page to the previous one
* @size: portion of page that we want to write
* @offset: starting offset in the page
* @bio_ret: must be valid pointer, newly allocated bio will be stored there
* @end_io_func: end_io callback for new bio
* @mirror_num: desired mirror to read/write
* @prev_bio_flags: flags of previous bio to see if we can merge the current one
* @bio_flags: flags of the current bio to see if we can merge them
*/
static int submit_extent_page(unsigned int opf, struct extent_io_tree *tree,
struct writeback_control *wbc,
struct page *page, u64 offset,
size_t size, unsigned long pg_offset,
struct bio **bio_ret,
bio_end_io_t end_io_func,
int mirror_num,
unsigned long prev_bio_flags,
unsigned long bio_flags,
bool force_bio_submit)
{
int ret = 0;
struct bio *bio;
size_t page_size = min_t(size_t, size, PAGE_SIZE);
sector_t sector = offset >> 9;
ASSERT(bio_ret);
if (*bio_ret) {
bool contig;
bool can_merge = true;
bio = *bio_ret;
if (prev_bio_flags & EXTENT_BIO_COMPRESSED)
contig = bio->bi_iter.bi_sector == sector;
else
contig = bio_end_sector(bio) == sector;
ASSERT(tree->ops);
if (btrfs_bio_fits_in_stripe(page, page_size, bio, bio_flags))
can_merge = false;
if (prev_bio_flags != bio_flags || !contig || !can_merge ||
force_bio_submit ||
bio_add_page(bio, page, page_size, pg_offset) < page_size) {
ret = submit_one_bio(bio, mirror_num, prev_bio_flags);
if (ret < 0) {
*bio_ret = NULL;
return ret;
}
bio = NULL;
} else {
if (wbc)
wbc_account_cgroup_owner(wbc, page, page_size);
return 0;
}
}
bio = btrfs_bio_alloc(offset);
bio_add_page(bio, page, page_size, pg_offset);
bio->bi_end_io = end_io_func;
bio->bi_private = tree;
bio->bi_write_hint = page->mapping->host->i_write_hint;
bio->bi_opf = opf;
if (wbc) {
struct block_device *bdev;
bdev = BTRFS_I(page->mapping->host)->root->fs_info->fs_devices->latest_bdev;
bio_set_dev(bio, bdev);
wbc_init_bio(wbc, bio);
wbc_account_cgroup_owner(wbc, page, page_size);
}
*bio_ret = bio;
return ret;
}
static void attach_extent_buffer_page(struct extent_buffer *eb,
struct page *page)
{
if (!PagePrivate(page)) {
SetPagePrivate(page);
get_page(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);
get_page(page);
set_page_private(page, EXTENT_PAGE_PRIVATE);
}
}
static struct extent_map *
__get_extent_map(struct inode *inode, struct page *page, size_t pg_offset,
u64 start, u64 len, get_extent_t *get_extent,
struct extent_map **em_cached)
{
struct extent_map *em;
if (em_cached && *em_cached) {
em = *em_cached;
if (extent_map_in_tree(em) && start >= em->start &&
start < extent_map_end(em)) {
refcount_inc(&em->refs);
return em;
}
free_extent_map(em);
*em_cached = NULL;
}
em = get_extent(BTRFS_I(inode), page, pg_offset, start, len);
if (em_cached && !IS_ERR_OR_NULL(em)) {
BUG_ON(*em_cached);
refcount_inc(&em->refs);
*em_cached = em;
}
return em;
}
/*
* 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
* return 0 on success, otherwise return error
*/
static int __do_readpage(struct extent_io_tree *tree,
struct page *page,
get_extent_t *get_extent,
struct extent_map **em_cached,
struct bio **bio, int mirror_num,
unsigned long *bio_flags, unsigned int read_flags,
u64 *prev_em_start)
{
struct inode *inode = page->mapping->host;
u64 start = page_offset(page);
const u64 end = start + PAGE_SIZE - 1;
u64 cur = start;
u64 extent_offset;
u64 last_byte = i_size_read(inode);
u64 block_start;
u64 cur_end;
struct extent_map *em;
int ret = 0;
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);
unlock_extent(tree, start, end);
goto out;
}
}
if (page->index == last_byte >> PAGE_SHIFT) {
char *userpage;
size_t zero_offset = offset_in_page(last_byte);
if (zero_offset) {
iosize = PAGE_SIZE - zero_offset;
userpage = kmap_atomic(page);
memset(userpage + zero_offset, 0, iosize);
flush_dcache_page(page);
kunmap_atomic(userpage);
}
}
while (cur <= end) {
bool force_bio_submit = false;
u64 offset;
if (cur >= last_byte) {
char *userpage;
struct extent_state *cached = NULL;
iosize = PAGE_SIZE - pg_offset;
userpage = kmap_atomic(page);
memset(userpage + pg_offset, 0, iosize);
flush_dcache_page(page);
kunmap_atomic(userpage);
set_extent_uptodate(tree, cur, cur + iosize - 1,
&cached, GFP_NOFS);
unlock_extent_cached(tree, cur,
cur + iosize - 1, &cached);
break;
}
em = __get_extent_map(inode, page, pg_offset, cur,
end - cur + 1, get_extent, em_cached);
if (IS_ERR_OR_NULL(em)) {
SetPageError(page);
unlock_extent(tree, cur, end);
break;
}
extent_offset = cur - em->start;
BUG_ON(extent_map_end(em) <= cur);
BUG_ON(end < cur);
if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
this_bio_flag |= EXTENT_BIO_COMPRESSED;
extent_set_compress_type(&this_bio_flag,
em->compress_type);
}
iosize = min(extent_map_end(em) - cur, end - cur + 1);
cur_end = min(extent_map_end(em) - 1, end);
iosize = ALIGN(iosize, blocksize);
if (this_bio_flag & EXTENT_BIO_COMPRESSED) {
disk_io_size = em->block_len;
offset = em->block_start;
} else {
offset = em->block_start + extent_offset;
disk_io_size = iosize;
}
block_start = em->block_start;
if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
block_start = EXTENT_MAP_HOLE;
/*
* If we have a file range that points to a compressed extent
* and it's followed by a consecutive file range that points to
* to the same compressed extent (possibly with a different
* offset and/or length, so it either points to the whole extent
* or only part of it), we must make sure we do not submit a
* single bio to populate the pages for the 2 ranges because
* this makes the compressed extent read zero out the pages
* belonging to the 2nd range. Imagine the following scenario:
*
* File layout
* [0 - 8K] [8K - 24K]
* | |
* | |
* points to extent X, points to extent X,
* offset 4K, length of 8K offset 0, length 16K
*
* [extent X, compressed length = 4K uncompressed length = 16K]
*
* If the bio to read the compressed extent covers both ranges,
* it will decompress extent X into the pages belonging to the
* first range and then it will stop, zeroing out the remaining
* pages that belong to the other range that points to extent X.
* So here we make sure we submit 2 bios, one for the first
* range and another one for the third range. Both will target
* the same physical extent from disk, but we can't currently
* make the compressed bio endio callback populate the pages
* for both ranges because each compressed bio is tightly
* coupled with a single extent map, and each range can have
* an extent map with a different offset value relative to the
* uncompressed data of our extent and different lengths. This
* is a corner case so we prioritize correctness over
* non-optimal behavior (submitting 2 bios for the same extent).
*/
if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) &&
prev_em_start && *prev_em_start != (u64)-1 &&
*prev_em_start != em->start)
force_bio_submit = true;
if (prev_em_start)
*prev_em_start = em->start;
free_extent_map(em);
em = NULL;
/* we've found a hole, just zero and go on */
if (block_start == EXTENT_MAP_HOLE) {
char *userpage;
struct extent_state *cached = NULL;
userpage = kmap_atomic(page);
memset(userpage + pg_offset, 0, iosize);
flush_dcache_page(page);
kunmap_atomic(userpage);
set_extent_uptodate(tree, cur, cur + iosize - 1,
&cached, GFP_NOFS);
unlock_extent_cached(tree, cur,
cur + iosize - 1, &cached);
cur = cur + iosize;
pg_offset += iosize;
continue;
}
/* the get_extent function already copied into the page */
if (test_range_bit(tree, cur, cur_end,
EXTENT_UPTODATE, 1, NULL)) {
check_page_uptodate(tree, page);
unlock_extent(tree, cur, cur + iosize - 1);
cur = cur + iosize;
pg_offset += iosize;
continue;
}
/* 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);
cur = cur + iosize;
pg_offset += iosize;
continue;
}
ret = submit_extent_page(REQ_OP_READ | read_flags, tree, NULL,
page, offset, disk_io_size,
pg_offset, bio,
end_bio_extent_readpage, mirror_num,
*bio_flags,
this_bio_flag,
force_bio_submit);
if (!ret) {
nr++;
*bio_flags = this_bio_flag;
} else {
SetPageError(page);
unlock_extent(tree, cur, cur + iosize - 1);
goto out;
}
cur = cur + iosize;
pg_offset += iosize;
}
out:
if (!nr) {
if (!PageError(page))
SetPageUptodate(page);
unlock_page(page);
}
return ret;
}
static inline void contiguous_readpages(struct extent_io_tree *tree,
struct page *pages[], int nr_pages,
u64 start, u64 end,
struct extent_map **em_cached,
struct bio **bio,
unsigned long *bio_flags,
u64 *prev_em_start)
{
struct btrfs_inode *inode = BTRFS_I(pages[0]->mapping->host);
int index;
btrfs_lock_and_flush_ordered_range(tree, inode, start, end, NULL);
for (index = 0; index < nr_pages; index++) {
__do_readpage(tree, pages[index], btrfs_get_extent, em_cached,
bio, 0, bio_flags, REQ_RAHEAD, prev_em_start);
put_page(pages[index]);
}
}
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,
unsigned int read_flags)
{
struct btrfs_inode *inode = BTRFS_I(page->mapping->host);
u64 start = page_offset(page);
u64 end = start + PAGE_SIZE - 1;
int ret;
btrfs_lock_and_flush_ordered_range(tree, inode, start, end, NULL);
ret = __do_readpage(tree, page, get_extent, NULL, bio, mirror_num,
bio_flags, read_flags, NULL);
return ret;
}
int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
get_extent_t *get_extent, int mirror_num)
{
struct bio *bio = NULL;
unsigned long bio_flags = 0;
int ret;
ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
&bio_flags, 0);
if (bio)
ret = submit_one_bio(bio, mirror_num, bio_flags);
return ret;
}
static void update_nr_written(struct writeback_control *wbc,
unsigned long nr_written)
{
wbc->nr_to_write -= nr_written;
}
/*
* helper for __extent_writepage, doing all of the delayed allocation setup.
*
* This returns 1 if btrfs_run_delalloc_range function did all the work required
* to write the page (copy into inline extent). In this case the IO has
* been started and the page is already unlocked.
*
* This returns 0 if all went well (page still locked)
* This returns < 0 if there were errors (page still locked)
*/
static noinline_for_stack int writepage_delalloc(struct inode *inode,
struct page *page, struct writeback_control *wbc,
u64 delalloc_start, unsigned long *nr_written)
{
u64 page_end = delalloc_start + PAGE_SIZE - 1;
bool found;
u64 delalloc_to_write = 0;
u64 delalloc_end = 0;
int ret;
int page_started = 0;
while (delalloc_end < page_end) {
found = find_lock_delalloc_range(inode, page,
&delalloc_start,
&delalloc_end);
if (!found) {
delalloc_start = delalloc_end + 1;
continue;
}
ret = btrfs_run_delalloc_range(inode, page, delalloc_start,
delalloc_end, &page_started, nr_written, wbc);
if (ret) {
SetPageError(page);
/*
* btrfs_run_delalloc_range should return < 0 for error
* but just in case, we use > 0 here meaning the IO is
* started, so we don't want to return > 0 unless
* things are going well.
*/
ret = ret < 0 ? ret : -EIO;
goto done;
}
/*
* delalloc_end is already one less than the total length, so
* we don't subtract one from PAGE_SIZE
*/
delalloc_to_write += (delalloc_end - delalloc_start +
PAGE_SIZE) >> PAGE_SHIFT;
delalloc_start = delalloc_end + 1;
}
if (wbc->nr_to_write < delalloc_to_write) {
int thresh = 8192;
if (delalloc_to_write < thresh * 2)
thresh = delalloc_to_write;
wbc->nr_to_write = min_t(u64, delalloc_to_write,
thresh);
}
/* did the fill delalloc function already unlock and start
* the IO?
*/
if (page_started) {
/*
* we've unlocked the page, so we can't update
* the mapping's writeback index, just update
* nr_to_write.
*/
wbc->nr_to_write -= *nr_written;
return 1;
}
ret = 0;
done:
return ret;
}
/*
* helper for __extent_writepage. This calls the writepage start hooks,
* and does the loop to map the page into extents and bios.
*
* We return 1 if the IO is started and the page is unlocked,
* 0 if all went well (page still locked)
* < 0 if there were errors (page still locked)
*/
static noinline_for_stack int __extent_writepage_io(struct inode *inode,
struct page *page,
struct writeback_control *wbc,
struct extent_page_data *epd,
loff_t i_size,
unsigned long nr_written,
int *nr_ret)
{
struct extent_io_tree *tree = epd->tree;
u64 start = page_offset(page);
u64 page_end = start + PAGE_SIZE - 1;
u64 end;
u64 cur = start;
u64 extent_offset;
u64 block_start;
u64 iosize;
struct extent_map *em;
size_t pg_offset = 0;
size_t blocksize;
int ret = 0;
int nr = 0;
const unsigned int write_flags = wbc_to_write_flags(wbc);
bool compressed;
ret = btrfs_writepage_cow_fixup(page, start, page_end);
if (ret) {
/* Fixup worker will requeue */
redirty_page_for_writepage(wbc, page);
update_nr_written(wbc, nr_written);
unlock_page(page);
return 1;
}
/*
* we don't want to touch the inode after unlocking the page,
* so we update the mapping writeback index now
*/
update_nr_written(wbc, nr_written + 1);
end = page_end;
blocksize = inode->i_sb->s_blocksize;
while (cur <= end) {
u64 em_end;
u64 offset;
if (cur >= i_size) {
btrfs_writepage_endio_finish_ordered(page, cur,
page_end, 1);
break;
}
em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, cur,
end - cur + 1);
if (IS_ERR_OR_NULL(em)) {
SetPageError(page);
ret = PTR_ERR_OR_ZERO(em);
break;
}
extent_offset = cur - em->start;
em_end = extent_map_end(em);
BUG_ON(em_end <= cur);
BUG_ON(end < cur);
iosize = min(em_end - cur, end - cur + 1);
iosize = ALIGN(iosize, blocksize);
offset = em->block_start + extent_offset;
block_start = em->block_start;
compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
free_extent_map(em);
em = NULL;
/*
* compressed and inline extents are written through other
* paths in the FS
*/
if (compressed || block_start == EXTENT_MAP_HOLE ||
block_start == EXTENT_MAP_INLINE) {
if (compressed)
nr++;
else
btrfs_writepage_endio_finish_ordered(page, cur,
cur + iosize - 1, 1);
cur += iosize;
pg_offset += iosize;
continue;
}
btrfs_set_range_writeback(tree, cur, cur + iosize - 1);
if (!PageWriteback(page)) {
btrfs_err(BTRFS_I(inode)->root->fs_info,
"page %lu not writeback, cur %llu end %llu",
page->index, cur, end);
}
ret = submit_extent_page(REQ_OP_WRITE | write_flags, tree, wbc,
page, offset, iosize, pg_offset,
&epd->bio,
end_bio_extent_writepage,
0, 0, 0, false);
if (ret) {
SetPageError(page);
if (PageWriteback(page))
end_page_writeback(page);
}
cur = cur + iosize;
pg_offset += iosize;
nr++;
}
*nr_ret = nr;
return ret;
}
/*
* the writepage semantics are similar to regular writepage. extent
* records are inserted to lock ranges in the tree, and as dirty areas
* are found, they are marked writeback. Then the lock bits are removed
* and the end_io handler clears the writeback ranges
*
* Return 0 if everything goes well.
* Return <0 for error.
*/
static int __extent_writepage(struct page *page, struct writeback_control *wbc,
struct extent_page_data *epd)
{
struct inode *inode = page->mapping->host;
u64 start = page_offset(page);
u64 page_end = start + PAGE_SIZE - 1;
int ret;
int nr = 0;
size_t pg_offset;
loff_t i_size = i_size_read(inode);
unsigned long end_index = i_size >> PAGE_SHIFT;
unsigned long nr_written = 0;
trace___extent_writepage(page, inode, wbc);
WARN_ON(!PageLocked(page));
ClearPageError(page);
pg_offset = offset_in_page(i_size);
if (page->index > end_index ||
(page->index == end_index && !pg_offset)) {
page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
unlock_page(page);
return 0;
}
if (page->index == end_index) {
char *userpage;
userpage = kmap_atomic(page);
memset(userpage + pg_offset, 0,
PAGE_SIZE - pg_offset);
kunmap_atomic(userpage);
flush_dcache_page(page);
}
set_page_extent_mapped(page);
if (!epd->extent_locked) {
ret = writepage_delalloc(inode, page, wbc, start, &nr_written);
if (ret == 1)
return 0;
if (ret)
goto done;
}
ret = __extent_writepage_io(inode, page, wbc, epd,
i_size, nr_written, &nr);
if (ret == 1)
return 0;
done:
if (nr == 0) {
/* make sure the mapping tag for page dirty gets cleared */
set_page_writeback(page);
end_page_writeback(page);
}
if (PageError(page)) {
ret = ret < 0 ? ret : -EIO;
end_extent_writepage(page, ret, start, page_end);
}
unlock_page(page);
ASSERT(ret <= 0);
return ret;
}
void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
{
wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
TASK_UNINTERRUPTIBLE);
}
static void end_extent_buffer_writeback(struct extent_buffer *eb)
{
clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
smp_mb__after_atomic();
wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
}
/*
* Lock eb pages and flush the bio if we can't the locks
*
* Return 0 if nothing went wrong
* Return >0 is same as 0, except bio is not submitted
* Return <0 if something went wrong, no page is locked
*/
static noinline_for_stack int lock_extent_buffer_for_io(struct extent_buffer *eb,
struct extent_page_data *epd)
{
struct btrfs_fs_info *fs_info = eb->fs_info;
int i, num_pages, failed_page_nr;
int flush = 0;
int ret = 0;
if (!btrfs_try_tree_write_lock(eb)) {
ret = flush_write_bio(epd);
if (ret < 0)
return ret;
flush = 1;
btrfs_tree_lock(eb);
}
if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
btrfs_tree_unlock(eb);
if (!epd->sync_io)
return 0;
if (!flush) {
ret = flush_write_bio(epd);
if (ret < 0)
return ret;
flush = 1;
}
while (1) {
wait_on_extent_buffer_writeback(eb);
btrfs_tree_lock(eb);
if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
break;
btrfs_tree_unlock(eb);
}
}
/*
* We need to do this to prevent races in people who check if the eb is
* under IO since we can end up having no IO bits set for a short period
* of time.
*/
spin_lock(&eb->refs_lock);
if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
spin_unlock(&eb->refs_lock);
btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
percpu_counter_add_batch(&fs_info->dirty_metadata_bytes,
-eb->len,
fs_info->dirty_metadata_batch);
ret = 1;
} else {
spin_unlock(&eb->refs_lock);
}
btrfs_tree_unlock(eb);
if (!ret)
return ret;
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
struct page *p = eb->pages[i];
if (!trylock_page(p)) {
if (!flush) {
int err;
err = flush_write_bio(epd);
if (err < 0) {
ret = err;
failed_page_nr = i;
goto err_unlock;
}
flush = 1;
}
lock_page(p);
}
}
return ret;
err_unlock:
/* Unlock already locked pages */
for (i = 0; i < failed_page_nr; i++)
unlock_page(eb->pages[i]);
/*
* Clear EXTENT_BUFFER_WRITEBACK and wake up anyone waiting on it.
* Also set back EXTENT_BUFFER_DIRTY so future attempts to this eb can
* be made and undo everything done before.
*/
btrfs_tree_lock(eb);
spin_lock(&eb->refs_lock);
set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
end_extent_buffer_writeback(eb);
spin_unlock(&eb->refs_lock);
percpu_counter_add_batch(&fs_info->dirty_metadata_bytes, eb->len,
fs_info->dirty_metadata_batch);
btrfs_clear_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
btrfs_tree_unlock(eb);
return ret;
}
static void set_btree_ioerr(struct page *page)
{
struct extent_buffer *eb = (struct extent_buffer *)page->private;
struct btrfs_fs_info *fs_info;
SetPageError(page);
if (test_and_set_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags))
return;
/*
* If we error out, we should add back the dirty_metadata_bytes
* to make it consistent.
*/
fs_info = eb->fs_info;
percpu_counter_add_batch(&fs_info->dirty_metadata_bytes,
eb->len, fs_info->dirty_metadata_batch);
/*
* If writeback for a btree extent that doesn't belong to a log tree
* failed, increment the counter transaction->eb_write_errors.
* We do this because while the transaction is running and before it's
* committing (when we call filemap_fdata[write|wait]_range against
* the btree inode), we might have
* btree_inode->i_mapping->a_ops->writepages() called by the VM - if it
* returns an error or an error happens during writeback, when we're
* committing the transaction we wouldn't know about it, since the pages
* can be no longer dirty nor marked anymore for writeback (if a
* subsequent modification to the extent buffer didn't happen before the
* transaction commit), which makes filemap_fdata[write|wait]_range not
* able to find the pages tagged with SetPageError at transaction
* commit time. So if this happens we must abort the transaction,
* otherwise we commit a super block with btree roots that point to
* btree nodes/leafs whose content on disk is invalid - either garbage
* or the content of some node/leaf from a past generation that got
* cowed or deleted and is no longer valid.
*
* Note: setting AS_EIO/AS_ENOSPC in the btree inode's i_mapping would
* not be enough - we need to distinguish between log tree extents vs
* non-log tree extents, and the next filemap_fdatawait_range() call
* will catch and clear such errors in the mapping - and that call might
* be from a log sync and not from a transaction commit. Also, checking
* for the eb flag EXTENT_BUFFER_WRITE_ERR at transaction commit time is
* not done and would not be reliable - the eb might have been released
* from memory and reading it back again means that flag would not be
* set (since it's a runtime flag, not persisted on disk).
*
* Using the flags below in the btree inode also makes us achieve the
* goal of AS_EIO/AS_ENOSPC when writepages() returns success, started
* writeback for all dirty pages and before filemap_fdatawait_range()
* is called, the writeback for all dirty pages had already finished
* with errors - because we were not using AS_EIO/AS_ENOSPC,
* filemap_fdatawait_range() would return success, as it could not know
* that writeback errors happened (the pages were no longer tagged for
* writeback).
*/
switch (eb->log_index) {
case -1:
set_bit(BTRFS_FS_BTREE_ERR, &eb->fs_info->flags);
break;
case 0:
set_bit(BTRFS_FS_LOG1_ERR, &eb->fs_info->flags);
break;
case 1:
set_bit(BTRFS_FS_LOG2_ERR, &eb->fs_info->flags);
break;
default:
BUG(); /* unexpected, logic error */
}
}
static void end_bio_extent_buffer_writepage(struct bio *bio)
{
struct bio_vec *bvec;
struct extent_buffer *eb;
int done;
struct bvec_iter_all iter_all;
ASSERT(!bio_flagged(bio, BIO_CLONED));
bio_for_each_segment_all(bvec, bio, iter_all) {
struct page *page = bvec->bv_page;
eb = (struct extent_buffer *)page->private;
BUG_ON(!eb);
done = atomic_dec_and_test(&eb->io_pages);
if (bio->bi_status ||
test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) {
ClearPageUptodate(page);
set_btree_ioerr(page);
}
end_page_writeback(page);
if (!done)
continue;
end_extent_buffer_writeback(eb);
}
bio_put(bio);
}
static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
struct writeback_control *wbc,
struct extent_page_data *epd)
{
struct btrfs_fs_info *fs_info = eb->fs_info;
struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
u64 offset = eb->start;
u32 nritems;
int i, num_pages;
unsigned long start, end;
unsigned int write_flags = wbc_to_write_flags(wbc) | REQ_META;
int ret = 0;
clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
num_pages = num_extent_pages(eb);
atomic_set(&eb->io_pages, num_pages);
/* set btree blocks beyond nritems with 0 to avoid stale content. */
nritems = btrfs_header_nritems(eb);
if (btrfs_header_level(eb) > 0) {
end = btrfs_node_key_ptr_offset(nritems);
memzero_extent_buffer(eb, end, eb->len - end);
} else {
/*
* leaf:
* header 0 1 2 .. N ... data_N .. data_2 data_1 data_0
*/
start = btrfs_item_nr_offset(nritems);
end = BTRFS_LEAF_DATA_OFFSET + leaf_data_end(eb);
memzero_extent_buffer(eb, start, end - start);
}
for (i = 0; i < num_pages; i++) {
struct page *p = eb->pages[i];
clear_page_dirty_for_io(p);
set_page_writeback(p);
ret = submit_extent_page(REQ_OP_WRITE | write_flags, tree, wbc,
p, offset, PAGE_SIZE, 0,
&epd->bio,
end_bio_extent_buffer_writepage,
0, 0, 0, false);
if (ret) {
set_btree_ioerr(p);
if (PageWriteback(p))
end_page_writeback(p);
if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
end_extent_buffer_writeback(eb);
ret = -EIO;
break;
}
offset += PAGE_SIZE;
update_nr_written(wbc, 1);
unlock_page(p);
}
if (unlikely(ret)) {
for (; i < num_pages; i++) {
struct page *p = eb->pages[i];
clear_page_dirty_for_io(p);
unlock_page(p);
}
}
return ret;
}
int btree_write_cache_pages(struct address_space *mapping,
struct writeback_control *wbc)
{
struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
struct extent_buffer *eb, *prev_eb = NULL;
struct extent_page_data epd = {
.bio = NULL,
.tree = tree,
.extent_locked = 0,
.sync_io = wbc->sync_mode == WB_SYNC_ALL,
};
int ret = 0;
int done = 0;
int nr_to_write_done = 0;
struct pagevec pvec;
int nr_pages;
pgoff_t index;
pgoff_t end; /* Inclusive */
int scanned = 0;
xa_mark_t tag;
pagevec_init(&pvec);
if (wbc->range_cyclic) {
index = mapping->writeback_index; /* Start from prev offset */
end = -1;
/*
* Start from the beginning does not need to cycle over the
* range, mark it as scanned.
*/
scanned = (index == 0);
} else {
index = wbc->range_start >> PAGE_SHIFT;
end = wbc->range_end >> PAGE_SHIFT;
scanned = 1;
}
if (wbc->sync_mode == WB_SYNC_ALL)
tag = PAGECACHE_TAG_TOWRITE;
else
tag = PAGECACHE_TAG_DIRTY;
retry:
if (wbc->sync_mode == WB_SYNC_ALL)
tag_pages_for_writeback(mapping, index, end);
while (!done && !nr_to_write_done && (index <= end) &&
(nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
tag))) {
unsigned i;
for (i = 0; i < nr_pages; i++) {
struct page *page = pvec.pages[i];
if (!PagePrivate(page))
continue;
spin_lock(&mapping->private_lock);
if (!PagePrivate(page)) {
spin_unlock(&mapping->private_lock);
continue;
}
eb = (struct extent_buffer *)page->private;
/*
* Shouldn't happen and normally this would be a BUG_ON
* but no sense in crashing the users box for something
* we can survive anyway.
*/
if (WARN_ON(!eb)) {
spin_unlock(&mapping->private_lock);
continue;
}
if (eb == prev_eb) {
spin_unlock(&mapping->private_lock);
continue;
}
ret = atomic_inc_not_zero(&eb->refs);
spin_unlock(&mapping->private_lock);
if (!ret)
continue;
prev_eb = eb;
ret = lock_extent_buffer_for_io(eb, &epd);
if (!ret) {
free_extent_buffer(eb);
continue;
} else if (ret < 0) {
done = 1;
free_extent_buffer(eb);
break;
}
ret = write_one_eb(eb, wbc, &epd);
if (ret) {
done = 1;
free_extent_buffer(eb);
break;
}
free_extent_buffer(eb);
/*
* the filesystem may choose to bump up nr_to_write.
* We have to make sure to honor the new nr_to_write
* at any time
*/
nr_to_write_done = wbc->nr_to_write <= 0;
}
pagevec_release(&pvec);
cond_resched();
}
if (!scanned && !done) {
/*
* We hit the last page and there is more work to be done: wrap
* back to the start of the file
*/
scanned = 1;
index = 0;
goto retry;
}
ASSERT(ret <= 0);
if (ret < 0) {
end_write_bio(&epd, ret);
return ret;
}
ret = flush_write_bio(&epd);
return ret;
}
/**
* write_cache_pages - walk the list of dirty pages of the given address space and write all of them.
* @mapping: address space structure to write
* @wbc: subtract the number of written pages from *@wbc->nr_to_write
* @data: data passed to __extent_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.
*/
static int extent_write_cache_pages(struct address_space *mapping,
struct writeback_control *wbc,
struct extent_page_data *epd)
{
struct inode *inode = mapping->host;
int ret = 0;
int done = 0;
int nr_to_write_done = 0;
struct pagevec pvec;
int nr_pages;
pgoff_t index;
pgoff_t end; /* Inclusive */
pgoff_t done_index;
int range_whole = 0;
int scanned = 0;
xa_mark_t tag;
/*
* We have to hold onto the inode so that ordered extents can do their
* work when the IO finishes. The alternative to this is failing to add
* an ordered extent if the igrab() fails there and that is a huge pain
* to deal with, so instead just hold onto the inode throughout the
* writepages operation. If it fails here we are freeing up the inode
* anyway and we'd rather not waste our time writing out stuff that is
* going to be truncated anyway.
*/
if (!igrab(inode))
return 0;
pagevec_init(&pvec);
if (wbc->range_cyclic) {
index = mapping->writeback_index; /* Start from prev offset */
end = -1;
/*
* Start from the beginning does not need to cycle over the
* range, mark it as scanned.
*/
scanned = (index == 0);
} else {
index = wbc->range_start >> PAGE_SHIFT;
end = wbc->range_end >> PAGE_SHIFT;
if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
range_whole = 1;
scanned = 1;
}
/*
* We do the tagged writepage as long as the snapshot flush bit is set
* and we are the first one who do the filemap_flush() on this inode.
*
* The nr_to_write == LONG_MAX is needed to make sure other flushers do
* not race in and drop the bit.
*/
if (range_whole && wbc->nr_to_write == LONG_MAX &&
test_and_clear_bit(BTRFS_INODE_SNAPSHOT_FLUSH,
&BTRFS_I(inode)->runtime_flags))
wbc->tagged_writepages = 1;
if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
tag = PAGECACHE_TAG_TOWRITE;
else
tag = PAGECACHE_TAG_DIRTY;
retry:
if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
tag_pages_for_writeback(mapping, index, end);
done_index = index;
while (!done && !nr_to_write_done && (index <= end) &&
(nr_pages = pagevec_lookup_range_tag(&pvec, mapping,
&index, end, tag))) {
unsigned i;
for (i = 0; i < nr_pages; i++) {
struct page *page = pvec.pages[i];
done_index = page->index + 1;
/*
* At this point we hold neither the i_pages lock nor
* the page lock: the page may be truncated or
* invalidated (changing page->mapping to NULL),
* or even swizzled back from swapper_space to
* tmpfs file mapping
*/
if (!trylock_page(page)) {
ret = flush_write_bio(epd);
BUG_ON(ret < 0);
lock_page(page);
}
if (unlikely(page->mapping != mapping)) {
unlock_page(page);
continue;
}
if (wbc->sync_mode != WB_SYNC_NONE) {
if (PageWriteback(page)) {
ret = flush_write_bio(epd);
BUG_ON(ret < 0);
}
wait_on_page_writeback(page);
}
if (PageWriteback(page) ||
!clear_page_dirty_for_io(page)) {
unlock_page(page);
continue;
}
ret = __extent_writepage(page, wbc, epd);
if (ret < 0) {
done = 1;
break;
}
/*
* the filesystem may choose to bump up nr_to_write.
* We have to make sure to honor the new nr_to_write
* at any time
*/
nr_to_write_done = wbc->nr_to_write <= 0;
}
pagevec_release(&pvec);
cond_resched();
}
if (!scanned && !done) {
/*
* We hit the last page and there is more work to be done: wrap
* back to the start of the file
*/
scanned = 1;
index = 0;
/*
* If we're looping we could run into a page that is locked by a
* writer and that writer could be waiting on writeback for a
* page in our current bio, and thus deadlock, so flush the
* write bio here.
*/
ret = flush_write_bio(epd);
if (!ret)
goto retry;
}
if (wbc->range_cyclic || (wbc->nr_to_write > 0 && range_whole))
mapping->writeback_index = done_index;
btrfs_add_delayed_iput(inode);
return ret;
}
int extent_write_full_page(struct page *page, struct writeback_control *wbc)
{
int ret;
struct extent_page_data epd = {
.bio = NULL,
.tree = &BTRFS_I(page->mapping->host)->io_tree,
.extent_locked = 0,
.sync_io = wbc->sync_mode == WB_SYNC_ALL,
};
ret = __extent_writepage(page, wbc, &epd);
ASSERT(ret <= 0);
if (ret < 0) {
end_write_bio(&epd, ret);
return ret;
}
ret = flush_write_bio(&epd);
ASSERT(ret <= 0);
return ret;
}
int extent_write_locked_range(struct inode *inode, u64 start, u64 end,
int mode)
{
int ret = 0;
struct address_space *mapping = inode->i_mapping;
struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
struct page *page;
unsigned long nr_pages = (end - start + PAGE_SIZE) >>
PAGE_SHIFT;
struct extent_page_data epd = {
.bio = NULL,
.tree = tree,
.extent_locked = 1,
.sync_io = mode == WB_SYNC_ALL,
};
struct writeback_control wbc_writepages = {
.sync_mode = mode,
.nr_to_write = nr_pages * 2,
.range_start = start,
.range_end = end + 1,
/* We're called from an async helper function */
.punt_to_cgroup = 1,
.no_cgroup_owner = 1,
};
wbc_attach_fdatawrite_inode(&wbc_writepages, inode);
while (start <= end) {
page = find_get_page(mapping, start >> PAGE_SHIFT);
if (clear_page_dirty_for_io(page))
ret = __extent_writepage(page, &wbc_writepages, &epd);
else {
btrfs_writepage_endio_finish_ordered(page, start,
start + PAGE_SIZE - 1, 1);
unlock_page(page);
}
put_page(page);
start += PAGE_SIZE;
}
ASSERT(ret <= 0);
if (ret == 0)
ret = flush_write_bio(&epd);
else
end_write_bio(&epd, ret);
wbc_detach_inode(&wbc_writepages);
return ret;
}
int extent_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
int ret = 0;
struct extent_page_data epd = {
.bio = NULL,
.tree = &BTRFS_I(mapping->host)->io_tree,
.extent_locked = 0,
.sync_io = wbc->sync_mode == WB_SYNC_ALL,
};
ret = extent_write_cache_pages(mapping, wbc, &epd);
ASSERT(ret <= 0);
if (ret < 0) {
end_write_bio(&epd, ret);
return ret;
}
ret = flush_write_bio(&epd);
return ret;
}
int extent_readpages(struct address_space *mapping, struct list_head *pages,
unsigned nr_pages)
{
struct bio *bio = NULL;
unsigned long bio_flags = 0;
struct page *pagepool[16];
struct extent_map *em_cached = NULL;
struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
int nr = 0;
u64 prev_em_start = (u64)-1;
while (!list_empty(pages)) {
u64 contig_end = 0;
for (nr = 0; nr < ARRAY_SIZE(pagepool) && !list_empty(pages);) {
struct page *page = lru_to_page(pages);
prefetchw(&page->flags);
list_del(&page->lru);
if (add_to_page_cache_lru(page, mapping, page->index,
readahead_gfp_mask(mapping))) {
put_page(page);
break;
}
pagepool[nr++] = page;
contig_end = page_offset(page) + PAGE_SIZE - 1;
}
if (nr) {
u64 contig_start = page_offset(pagepool[0]);
ASSERT(contig_start + nr * PAGE_SIZE - 1 == contig_end);
contiguous_readpages(tree, pagepool, nr, contig_start,
contig_end, &em_cached, &bio, &bio_flags,
&prev_em_start);
}
}
if (em_cached)
free_extent_map(em_cached);
if (bio)
return submit_one_bio(bio, 0, bio_flags);
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)
{
struct extent_state *cached_state = NULL;
u64 start = page_offset(page);
u64 end = start + PAGE_SIZE - 1;
size_t blocksize = page->mapping->host->i_sb->s_blocksize;
start += ALIGN(offset, blocksize);
if (start > end)
return 0;
lock_extent_bits(tree, start, end, &cached_state);
wait_on_page_writeback(page);
clear_extent_bit(tree, start, end, EXTENT_LOCKED | EXTENT_DELALLOC |
EXTENT_DO_ACCOUNTING, 1, 1, &cached_state);
return 0;
}
/*
* 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.
*/
static int try_release_extent_state(struct extent_io_tree *tree,
struct page *page, gfp_t mask)
{
u64 start = page_offset(page);
u64 end = start + PAGE_SIZE - 1;
int ret = 1;
if (test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL)) {
ret = 0;
} else {
/*
* at this point we can safely clear everything except the
* locked bit and the nodatasum bit
*/
ret = __clear_extent_bit(tree, start, end,
~(EXTENT_LOCKED | EXTENT_NODATASUM),
0, 0, NULL, mask, NULL);
/* if clear_extent_bit failed for enomem reasons,
* we can't allow the release to continue.
*/
if (ret < 0)
ret = 0;
else
ret = 1;
}
return ret;
}
/*
* 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 page *page, gfp_t mask)
{
struct extent_map *em;
u64 start = page_offset(page);
u64 end = start + PAGE_SIZE - 1;
struct btrfs_inode *btrfs_inode = BTRFS_I(page->mapping->host);
struct extent_io_tree *tree = &btrfs_inode->io_tree;
struct extent_map_tree *map = &btrfs_inode->extent_tree;
if (gfpflags_allow_blocking(mask) &&
page->mapping->host->i_size > SZ_16M) {
u64 len;
while (start <= end) {
len = end - start + 1;
write_lock(&map->lock);
em = lookup_extent_mapping(map, start, len);
if (!em) {
write_unlock(&map->lock);
break;
}
if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
em->start != start) {
write_unlock(&map->lock);
free_extent_map(em);
break;
}
if (!test_range_bit(tree, em->start,
extent_map_end(em) - 1,
EXTENT_LOCKED, 0, NULL)) {
set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
&btrfs_inode->runtime_flags);
remove_extent_mapping(map, em);
/* once for the rb tree */
free_extent_map(em);
}
start = extent_map_end(em);
write_unlock(&map->lock);
/* once for us */
free_extent_map(em);
}
}
return try_release_extent_state(tree, page, mask);
}
/*
* helper function for fiemap, which doesn't want to see any holes.
* This maps until we find something past 'last'
*/
static struct extent_map *get_extent_skip_holes(struct inode *inode,
u64 offset, u64 last)
{
u64 sectorsize = btrfs_inode_sectorsize(inode);
struct extent_map *em;
u64 len;
if (offset >= last)
return NULL;
while (1) {
len = last - offset;
if (len == 0)
break;
len = ALIGN(len, sectorsize);
em = btrfs_get_extent_fiemap(BTRFS_I(inode), offset, len);
if (IS_ERR_OR_NULL(em))
return em;
/* if this isn't a hole return it */
if (em->block_start != EXTENT_MAP_HOLE)
return em;
/* this is a hole, advance to the next extent */
offset = extent_map_end(em);
free_extent_map(em);
if (offset >= last)
break;
}
return NULL;
}
/*
* To cache previous fiemap extent
*
* Will be used for merging fiemap extent
*/
struct fiemap_cache {
u64 offset;
u64 phys;
u64 len;
u32 flags;
bool cached;
};
/*
* Helper to submit fiemap extent.
*
* Will try to merge current fiemap extent specified by @offset, @phys,
* @len and @flags with cached one.
* And only when we fails to merge, cached one will be submitted as
* fiemap extent.
*
* Return value is the same as fiemap_fill_next_extent().
*/
static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
struct fiemap_cache *cache,
u64 offset, u64 phys, u64 len, u32 flags)
{
int ret = 0;
if (!cache->cached)
goto assign;
/*
* Sanity check, extent_fiemap() should have ensured that new
* fiemap extent won't overlap with cached one.
* Not recoverable.
*
* NOTE: Physical address can overlap, due to compression
*/
if (cache->offset + cache->len > offset) {
WARN_ON(1);
return -EINVAL;
}
/*
* Only merges fiemap extents if
* 1) Their logical addresses are continuous
*
* 2) Their physical addresses are continuous
* So truly compressed (physical size smaller than logical size)
* extents won't get merged with each other
*
* 3) Share same flags except FIEMAP_EXTENT_LAST
* So regular extent won't get merged with prealloc extent
*/
if (cache->offset + cache->len == offset &&
cache->phys + cache->len == phys &&
(cache->flags & ~FIEMAP_EXTENT_LAST) ==
(flags & ~FIEMAP_EXTENT_LAST)) {
cache->len += len;
cache->flags |= flags;
goto try_submit_last;
}
/* Not mergeable, need to submit cached one */
ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
cache->len, cache->flags);
cache->cached = false;
if (ret)
return ret;
assign:
cache->cached = true;
cache->offset = offset;
cache->phys = phys;
cache->len = len;
cache->flags = flags;
try_submit_last:
if (cache->flags & FIEMAP_EXTENT_LAST) {
ret = fiemap_fill_next_extent(fieinfo, cache->offset,
cache->phys, cache->len, cache->flags);
cache->cached = false;
}
return ret;
}
/*
* Emit last fiemap cache
*
* The last fiemap cache may still be cached in the following case:
* 0 4k 8k
* |<- Fiemap range ->|
* |<------------ First extent ----------->|
*
* In this case, the first extent range will be cached but not emitted.
* So we must emit it before ending extent_fiemap().
*/
static int emit_last_fiemap_cache(struct fiemap_extent_info *fieinfo,
struct fiemap_cache *cache)
{
int ret;
if (!cache->cached)
return 0;
ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
cache->len, cache->flags);
cache->cached = false;
if (ret > 0)
ret = 0;
return ret;
}
int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
__u64 start, __u64 len)
{
int ret = 0;
u64 off = start;
u64 max = start + len;
u32 flags = 0;
u32 found_type;
u64 last;
u64 last_for_get_extent = 0;
u64 disko = 0;
u64 isize = i_size_read(inode);
struct btrfs_key found_key;
struct extent_map *em = NULL;
struct extent_state *cached_state = NULL;
struct btrfs_path *path;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct fiemap_cache cache = { 0 };
struct ulist *roots;
struct ulist *tmp_ulist;
int end = 0;
u64 em_start = 0;
u64 em_len = 0;
u64 em_end = 0;
if (len == 0)
return -EINVAL;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->leave_spinning = 1;
roots = ulist_alloc(GFP_KERNEL);
tmp_ulist = ulist_alloc(GFP_KERNEL);
if (!roots || !tmp_ulist) {
ret = -ENOMEM;
goto out_free_ulist;
}
start = round_down(start, btrfs_inode_sectorsize(inode));
len = round_up(max, btrfs_inode_sectorsize(inode)) - start;
/*
* lookup the last file extent. We're not using i_size here
* because there might be preallocation past i_size
*/
ret = btrfs_lookup_file_extent(NULL, root, path,
btrfs_ino(BTRFS_I(inode)), -1, 0);
if (ret < 0) {
goto out_free_ulist;
} else {
WARN_ON(!ret);
if (ret == 1)
ret = 0;
}
path->slots[0]--;
btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
found_type = found_key.type;
/* No extents, but there might be delalloc bits */
if (found_key.objectid != btrfs_ino(BTRFS_I(inode)) ||
found_type != BTRFS_EXTENT_DATA_KEY) {
/* have to trust i_size as the end */
last = (u64)-1;
last_for_get_extent = isize;
} else {
/*
* remember the start of the last extent. There are a
* bunch of different factors that go into the length of the
* extent, so its much less complex to remember where it started
*/
last = found_key.offset;
last_for_get_extent = last + 1;
}
btrfs_release_path(path);
/*
* we might have some extents allocated but more delalloc past those
* extents. so, we trust isize unless the start of the last extent is
* beyond isize
*/
if (last < isize) {
last = (u64)-1;
last_for_get_extent = isize;
}
lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len - 1,
&cached_state);
em = get_extent_skip_holes(inode, start, last_for_get_extent);
if (!em)
goto out;
if (IS_ERR(em)) {
ret = PTR_ERR(em);
goto out;
}
while (!end) {
u64 offset_in_extent = 0;
/* break if the extent we found is outside the range */
if (em->start >= max || extent_map_end(em) < off)
break;
/*
* get_extent may return an extent that starts before our
* requested range. We have to make sure the ranges
* we return to fiemap always move forward and don't
* overlap, so adjust the offsets here
*/
em_start = max(em->start, off);
/*
* record the offset from the start of the extent
* for adjusting the disk offset below. Only do this if the
* extent isn't compressed since our in ram offset may be past
* what we have actually allocated on disk.
*/
if (!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
offset_in_extent = em_start - em->start;
em_end = extent_map_end(em);
em_len = em_end - em_start;
flags = 0;
if (em->block_start < EXTENT_MAP_LAST_BYTE)
disko = em->block_start + offset_in_extent;
else
disko = 0;
/*
* bump off for our next call to get_extent
*/
off = extent_map_end(em);
if (off >= max)
end = 1;
if (em->block_start == EXTENT_MAP_LAST_BYTE) {
end = 1;
flags |= FIEMAP_EXTENT_LAST;
} else if (em->block_start == EXTENT_MAP_INLINE) {
flags |= (FIEMAP_EXTENT_DATA_INLINE |
FIEMAP_EXTENT_NOT_ALIGNED);
} else if (em->block_start == EXTENT_MAP_DELALLOC) {
flags |= (FIEMAP_EXTENT_DELALLOC |
FIEMAP_EXTENT_UNKNOWN);
} else if (fieinfo->fi_extents_max) {
u64 bytenr = em->block_start -
(em->start - em->orig_start);
/*
* As btrfs supports shared space, this information
* can be exported to userspace tools via
* flag FIEMAP_EXTENT_SHARED. If fi_extents_max == 0
* then we're just getting a count and we can skip the
* lookup stuff.
*/
ret = btrfs_check_shared(root,
btrfs_ino(BTRFS_I(inode)),
bytenr, roots, tmp_ulist);
if (ret < 0)
goto out_free;
if (ret)
flags |= FIEMAP_EXTENT_SHARED;
ret = 0;
}
if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
flags |= FIEMAP_EXTENT_ENCODED;
if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
flags |= FIEMAP_EXTENT_UNWRITTEN;
free_extent_map(em);
em = NULL;
if ((em_start >= last) || em_len == (u64)-1 ||
(last == (u64)-1 && isize <= em_end)) {
flags |= FIEMAP_EXTENT_LAST;
end = 1;
}
/* now scan forward to see if this is really the last extent. */
em = get_extent_skip_holes(inode, off, last_for_get_extent);
if (IS_ERR(em)) {
ret = PTR_ERR(em);
goto out;
}
if (!em) {
flags |= FIEMAP_EXTENT_LAST;
end = 1;
}
ret = emit_fiemap_extent(fieinfo, &cache, em_start, disko,
em_len, flags);
if (ret) {
if (ret == 1)
ret = 0;
goto out_free;
}
}
out_free:
if (!ret)
ret = emit_last_fiemap_cache(fieinfo, &cache);
free_extent_map(em);
out:
unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len - 1,
&cached_state);
out_free_ulist:
btrfs_free_path(path);
ulist_free(roots);
ulist_free(tmp_ulist);
return ret;
}
static void __free_extent_buffer(struct extent_buffer *eb)
{
btrfs_leak_debug_del(&eb->leak_list);
kmem_cache_free(extent_buffer_cache, eb);
}
int extent_buffer_under_io(struct extent_buffer *eb)
{
return (atomic_read(&eb->io_pages) ||
test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
}
/*
* Release all pages attached to the extent buffer.
*/
static void btrfs_release_extent_buffer_pages(struct extent_buffer *eb)
{
int i;
int num_pages;
int mapped = !test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags);
BUG_ON(extent_buffer_under_io(eb));
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
struct page *page = eb->pages[i];
if (!page)
continue;
if (mapped)
spin_lock(&page->mapping->private_lock);
/*
* We do this since we'll remove the pages after we've
* removed the eb from the radix tree, so we could race
* and have this page now attached to the new eb. So
* only clear page_private if it's still connected to
* this eb.
*/
if (PagePrivate(page) &&
page->private == (unsigned long)eb) {
BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
BUG_ON(PageDirty(page));
BUG_ON(PageWriteback(page));
/*
* We need to make sure we haven't be attached
* to a new eb.
*/
ClearPagePrivate(page);
set_page_private(page, 0);
/* One for the page private */
put_page(page);
}
if (mapped)
spin_unlock(&page->mapping->private_lock);
/* One for when we allocated the page */
put_page(page);
}
}
/*
* Helper for releasing the extent buffer.
*/
static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
{
btrfs_release_extent_buffer_pages(eb);
__free_extent_buffer(eb);
}
static struct extent_buffer *
__alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
unsigned long len)
{
struct extent_buffer *eb = NULL;
eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS|__GFP_NOFAIL);
eb->start = start;
eb->len = len;
eb->fs_info = fs_info;
eb->bflags = 0;
rwlock_init(&eb->lock);
atomic_set(&eb->blocking_readers, 0);
eb->blocking_writers = 0;
eb->lock_nested = false;
init_waitqueue_head(&eb->write_lock_wq);
init_waitqueue_head(&eb->read_lock_wq);
btrfs_leak_debug_add(&eb->leak_list, &buffers);
spin_lock_init(&eb->refs_lock);
atomic_set(&eb->refs, 1);
atomic_set(&eb->io_pages, 0);
/*
* Sanity checks, currently the maximum is 64k covered by 16x 4k pages
*/
BUILD_BUG_ON(BTRFS_MAX_METADATA_BLOCKSIZE
> MAX_INLINE_EXTENT_BUFFER_SIZE);
BUG_ON(len > MAX_INLINE_EXTENT_BUFFER_SIZE);
#ifdef CONFIG_BTRFS_DEBUG
eb->spinning_writers = 0;
atomic_set(&eb->spinning_readers, 0);
atomic_set(&eb->read_locks, 0);
eb->write_locks = 0;
#endif
return eb;
}
struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src)
{
int i;
struct page *p;
struct extent_buffer *new;
int num_pages = num_extent_pages(src);
new = __alloc_extent_buffer(src->fs_info, src->start, src->len);
if (new == NULL)
return NULL;
for (i = 0; i < num_pages; i++) {
p = alloc_page(GFP_NOFS);
if (!p) {
btrfs_release_extent_buffer(new);
return NULL;
}
attach_extent_buffer_page(new, p);
WARN_ON(PageDirty(p));
SetPageUptodate(p);
new->pages[i] = p;
copy_page(page_address(p), page_address(src->pages[i]));
}
set_bit(EXTENT_BUFFER_UPTODATE, &new->bflags);
set_bit(EXTENT_BUFFER_UNMAPPED, &new->bflags);
return new;
}
struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
u64 start, unsigned long len)
{
struct extent_buffer *eb;
int num_pages;
int i;
eb = __alloc_extent_buffer(fs_info, start, len);
if (!eb)
return NULL;
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
eb->pages[i] = alloc_page(GFP_NOFS);
if (!eb->pages[i])
goto err;
}
set_extent_buffer_uptodate(eb);
btrfs_set_header_nritems(eb, 0);
set_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags);
return eb;
err:
for (; i > 0; i--)
__free_page(eb->pages[i - 1]);
__free_extent_buffer(eb);
return NULL;
}
struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
u64 start)
{
return __alloc_dummy_extent_buffer(fs_info, start, fs_info->nodesize);
}
static void check_buffer_tree_ref(struct extent_buffer *eb)
{
int refs;
/* the ref bit is tricky. We have to make sure it is set
* if we have the buffer dirty. Otherwise the
* code to free a buffer can end up dropping a dirty
* page
*
* Once the ref bit is set, it won't go away while the
* buffer is dirty or in writeback, and it also won't
* go away while we have the reference count on the
* eb bumped.
*
* We can't just set the ref bit without bumping the
* ref on the eb because free_extent_buffer might
* see the ref bit and try to clear it. If this happens
* free_extent_buffer might end up dropping our original
* ref by mistake and freeing the page before we are able
* to add one more ref.
*
* So bump the ref count first, then set the bit. If someone
* beat us to it, drop the ref we added.
*/
refs = atomic_read(&eb->refs);
if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
return;
spin_lock(&eb->refs_lock);
if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
atomic_inc(&eb->refs);
spin_unlock(&eb->refs_lock);
}
static void mark_extent_buffer_accessed(struct extent_buffer *eb,
struct page *accessed)
{
int num_pages, i;
check_buffer_tree_ref(eb);
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
struct page *p = eb->pages[i];
if (p != accessed)
mark_page_accessed(p);
}
}
struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
u64 start)
{
struct extent_buffer *eb;
rcu_read_lock();
eb = radix_tree_lookup(&fs_info->buffer_radix,
start >> PAGE_SHIFT);
if (eb && atomic_inc_not_zero(&eb->refs)) {
rcu_read_unlock();
/*
* Lock our eb's refs_lock to avoid races with
* free_extent_buffer. When we get our eb it might be flagged
* with EXTENT_BUFFER_STALE and another task running
* free_extent_buffer might have seen that flag set,
* eb->refs == 2, that the buffer isn't under IO (dirty and
* writeback flags not set) and it's still in the tree (flag
* EXTENT_BUFFER_TREE_REF set), therefore being in the process
* of decrementing the extent buffer's reference count twice.
* So here we could race and increment the eb's reference count,
* clear its stale flag, mark it as dirty and drop our reference
* before the other task finishes executing free_extent_buffer,
* which would later result in an attempt to free an extent
* buffer that is dirty.
*/
if (test_bit(EXTENT_BUFFER_STALE, &eb->bflags)) {
spin_lock(&eb->refs_lock);
spin_unlock(&eb->refs_lock);
}
mark_extent_buffer_accessed(eb, NULL);
return eb;
}
rcu_read_unlock();
return NULL;
}
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
u64 start)
{
struct extent_buffer *eb, *exists = NULL;
int ret;
eb = find_extent_buffer(fs_info, start);
if (eb)
return eb;
eb = alloc_dummy_extent_buffer(fs_info, start);
if (!eb)
return ERR_PTR(-ENOMEM);
eb->fs_info = fs_info;
again:
ret = radix_tree_preload(GFP_NOFS);
if (ret) {
exists = ERR_PTR(ret);
goto free_eb;
}
spin_lock(&fs_info->buffer_lock);
ret = radix_tree_insert(&fs_info->buffer_radix,
start >> PAGE_SHIFT, eb);
spin_unlock(&fs_info->buffer_lock);
radix_tree_preload_end();
if (ret == -EEXIST) {
exists = find_extent_buffer(fs_info, start);
if (exists)
goto free_eb;
else
goto again;
}
check_buffer_tree_ref(eb);
set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
return eb;
free_eb:
btrfs_release_extent_buffer(eb);
return exists;
}
#endif
struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
u64 start)
{
unsigned long len = fs_info->nodesize;
int num_pages;
int i;
unsigned long index = start >> PAGE_SHIFT;
struct extent_buffer *eb;
struct extent_buffer *exists = NULL;
struct page *p;
struct address_space *mapping = fs_info->btree_inode->i_mapping;
int uptodate = 1;
int ret;
if (!IS_ALIGNED(start, fs_info->sectorsize)) {
btrfs_err(fs_info, "bad tree block start %llu", start);
return ERR_PTR(-EINVAL);
}
eb = find_extent_buffer(fs_info, start);
if (eb)
return eb;
eb = __alloc_extent_buffer(fs_info, start, len);
if (!eb)
return ERR_PTR(-ENOMEM);
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++, index++) {
p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL);
if (!p) {
exists = ERR_PTR(-ENOMEM);
goto free_eb;
}
spin_lock(&mapping->private_lock);
if (PagePrivate(p)) {
/*
* We could have already allocated an eb for this page
* and attached one so lets see if we can get a ref on
* the existing eb, and if we can we know it's good and
* we can just return that one, else we know we can just
* overwrite page->private.
*/
exists = (struct extent_buffer *)p->private;
if (atomic_inc_not_zero(&exists->refs)) {
spin_unlock(&mapping->private_lock);
unlock_page(p);
put_page(p);
mark_extent_buffer_accessed(exists, p);
goto free_eb;
}
exists = NULL;
/*
* Do this so attach doesn't complain and we need to
* drop the ref the old guy had.
*/
ClearPagePrivate(p);
WARN_ON(PageDirty(p));
put_page(p);
}
attach_extent_buffer_page(eb, p);
spin_unlock(&mapping->private_lock);
WARN_ON(PageDirty(p));
eb->pages[i] = p;
if (!PageUptodate(p))
uptodate = 0;
/*
* We can't unlock the pages just yet since the extent buffer
* hasn't been properly inserted in the radix tree, this
* opens a race with btree_releasepage which can free a page
* while we are still filling in all pages for the buffer and
* we could crash.
*/
}
if (uptodate)
set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
again:
ret = radix_tree_preload(GFP_NOFS);
if (ret) {
exists = ERR_PTR(ret);
goto free_eb;
}
spin_lock(&fs_info->buffer_lock);
ret = radix_tree_insert(&fs_info->buffer_radix,
start >> PAGE_SHIFT, eb);
spin_unlock(&fs_info->buffer_lock);
radix_tree_preload_end();
if (ret == -EEXIST) {
exists = find_extent_buffer(fs_info, start);
if (exists)
goto free_eb;
else
goto again;
}
/* add one reference for the tree */
check_buffer_tree_ref(eb);
set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
/*
* Now it's safe to unlock the pages because any calls to
* btree_releasepage will correctly detect that a page belongs to a
* live buffer and won't free them prematurely.
*/
for (i = 0; i < num_pages; i++)
unlock_page(eb->pages[i]);
return eb;
free_eb:
WARN_ON(!atomic_dec_and_test(&eb->refs));
for (i = 0; i < num_pages; i++) {
if (eb->pages[i])
unlock_page(eb->pages[i]);
}
btrfs_release_extent_buffer(eb);
return exists;
}
static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
{
struct extent_buffer *eb =
container_of(head, struct extent_buffer, rcu_head);
__free_extent_buffer(eb);
}
static int release_extent_buffer(struct extent_buffer *eb)
{
lockdep_assert_held(&eb->refs_lock);
WARN_ON(atomic_read(&eb->refs) == 0);
if (atomic_dec_and_test(&eb->refs)) {
if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
struct btrfs_fs_info *fs_info = eb->fs_info;
spin_unlock(&eb->refs_lock);
spin_lock(&fs_info->buffer_lock);
radix_tree_delete(&fs_info->buffer_radix,
eb->start >> PAGE_SHIFT);
spin_unlock(&fs_info->buffer_lock);
} else {
spin_unlock(&eb->refs_lock);
}
/* Should be safe to release our pages at this point */
btrfs_release_extent_buffer_pages(eb);
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
if (unlikely(test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags))) {
__free_extent_buffer(eb);
return 1;
}
#endif
call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
return 1;
}
spin_unlock(&eb->refs_lock);
return 0;
}
void free_extent_buffer(struct extent_buffer *eb)
{
int refs;
int old;
if (!eb)
return;
while (1) {
refs = atomic_read(&eb->refs);
if ((!test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags) && refs <= 3)
|| (test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags) &&
refs == 1))
break;
old = atomic_cmpxchg(&eb->refs, refs, refs - 1);
if (old == refs)
return;
}
spin_lock(&eb->refs_lock);
if (atomic_read(&eb->refs) == 2 &&
test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
!extent_buffer_under_io(eb) &&
test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
atomic_dec(&eb->refs);
/*
* I know this is terrible, but it's temporary until we stop tracking
* the uptodate bits and such for the extent buffers.
*/
release_extent_buffer(eb);
}
void free_extent_buffer_stale(struct extent_buffer *eb)
{
if (!eb)
return;
spin_lock(&eb->refs_lock);
set_bit(EXTENT_BUFFER_STALE, &eb->bflags);
if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
atomic_dec(&eb->refs);
release_extent_buffer(eb);
}
void clear_extent_buffer_dirty(struct extent_buffer *eb)
{
int i;
int num_pages;
struct page *page;
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
page = eb->pages[i];
if (!PageDirty(page))
continue;
lock_page(page);
WARN_ON(!PagePrivate(page));
clear_page_dirty_for_io(page);
xa_lock_irq(&page->mapping->i_pages);
if (!PageDirty(page))
__xa_clear_mark(&page->mapping->i_pages,
page_index(page), PAGECACHE_TAG_DIRTY);
xa_unlock_irq(&page->mapping->i_pages);
ClearPageError(page);
unlock_page(page);
}
WARN_ON(atomic_read(&eb->refs) == 0);
}
bool set_extent_buffer_dirty(struct extent_buffer *eb)
{
int i;
int num_pages;
bool was_dirty;
check_buffer_tree_ref(eb);
was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
num_pages = num_extent_pages(eb);
WARN_ON(atomic_read(&eb->refs) == 0);
WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
if (!was_dirty)
for (i = 0; i < num_pages; i++)
set_page_dirty(eb->pages[i]);
#ifdef CONFIG_BTRFS_DEBUG
for (i = 0; i < num_pages; i++)
ASSERT(PageDirty(eb->pages[i]));
#endif
return was_dirty;
}
void clear_extent_buffer_uptodate(struct extent_buffer *eb)
{
int i;
struct page *page;
int num_pages;
clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
page = eb->pages[i];
if (page)
ClearPageUptodate(page);
}
}
void set_extent_buffer_uptodate(struct extent_buffer *eb)
{
int i;
struct page *page;
int num_pages;
set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
page = eb->pages[i];
SetPageUptodate(page);
}
}
int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num)
{
int i;
struct page *page;
int err;
int ret = 0;
int locked_pages = 0;
int all_uptodate = 1;
int num_pages;
unsigned long num_reads = 0;
struct bio *bio = NULL;
unsigned long bio_flags = 0;
struct extent_io_tree *tree = &BTRFS_I(eb->fs_info->btree_inode)->io_tree;
if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
return 0;
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
page = eb->pages[i];
if (wait == WAIT_NONE) {
if (!trylock_page(page))
goto unlock_exit;
} else {
lock_page(page);
}
locked_pages++;
}
/*
* We need to firstly lock all pages to make sure that
* the uptodate bit of our pages won't be affected by
* clear_extent_buffer_uptodate().
*/
for (i = 0; i < num_pages; i++) {
page = eb->pages[i];
if (!PageUptodate(page)) {
num_reads++;
all_uptodate = 0;
}
}
if (all_uptodate) {
set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
goto unlock_exit;
}
clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
eb->read_mirror = 0;
atomic_set(&eb->io_pages, num_reads);
for (i = 0; i < num_pages; i++) {
page = eb->pages[i];
if (!PageUptodate(page)) {
if (ret) {
atomic_dec(&eb->io_pages);
unlock_page(page);
continue;
}
ClearPageError(page);
err = __extent_read_full_page(tree, page,
btree_get_extent, &bio,
mirror_num, &bio_flags,
REQ_META);
if (err) {
ret = err;
/*
* We use &bio in above __extent_read_full_page,
* so we ensure that if it returns error, the
* current page fails to add itself to bio and
* it's been unlocked.
*
* We must dec io_pages by ourselves.
*/
atomic_dec(&eb->io_pages);
}
} else {
unlock_page(page);
}
}
if (bio) {
err = submit_one_bio(bio, mirror_num, bio_flags);
if (err)
return err;
}
if (ret || wait != WAIT_COMPLETE)
return ret;
for (i = 0; i < num_pages; i++) {
page = eb->pages[i];
wait_on_page_locked(page);
if (!PageUptodate(page))
ret = -EIO;
}
return ret;
unlock_exit:
while (locked_pages > 0) {
locked_pages--;
page = eb->pages[locked_pages];
unlock_page(page);
}
return ret;
}
void read_extent_buffer(const 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 = offset_in_page(eb->start);
unsigned long i = (start_offset + start) >> PAGE_SHIFT;
if (start + len > eb->len) {
WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, wanted %lu %lu\n",
eb->start, eb->len, start, len);
memset(dst, 0, len);
return;
}
offset = offset_in_page(start_offset + start);
while (len > 0) {
page = eb->pages[i];
cur = min(len, (PAGE_SIZE - offset));
kaddr = page_address(page);
memcpy(dst, kaddr + offset, cur);
dst += cur;
len -= cur;
offset = 0;
i++;
}
}
int read_extent_buffer_to_user(const struct extent_buffer *eb,
void __user *dstv,
unsigned long start, unsigned long len)
{
size_t cur;
size_t offset;
struct page *page;
char *kaddr;
char __user *dst = (char __user *)dstv;
size_t start_offset = offset_in_page(eb->start);
unsigned long i = (start_offset + start) >> PAGE_SHIFT;
int ret = 0;
WARN_ON(start > eb->len);
WARN_ON(start + len > eb->start + eb->len);
offset = offset_in_page(start_offset + start);
while (len > 0) {
page = eb->pages[i];
cur = min(len, (PAGE_SIZE - offset));
kaddr = page_address(page);
if (copy_to_user(dst, kaddr + offset, cur)) {
ret = -EFAULT;
break;
}
dst += cur;
len -= cur;
offset = 0;
i++;
}
return ret;
}
/*
* return 0 if the item is found within a page.
* return 1 if the item spans two pages.
* return -EINVAL otherwise.
*/
int map_private_extent_buffer(const struct extent_buffer *eb,
unsigned long start, unsigned long min_len,
char **map, unsigned long *map_start,
unsigned long *map_len)
{
size_t offset;
char *kaddr;
struct page *p;
size_t start_offset = offset_in_page(eb->start);
unsigned long i = (start_offset + start) >> PAGE_SHIFT;
unsigned long end_i = (start_offset + start + min_len - 1) >>
PAGE_SHIFT;
if (start + min_len > eb->len) {
WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, wanted %lu %lu\n",
eb->start, eb->len, start, min_len);
return -EINVAL;
}
if (i != end_i)
return 1;
if (i == 0) {
offset = start_offset;
*map_start = 0;
} else {
offset = 0;
*map_start = ((u64)i << PAGE_SHIFT) - start_offset;
}
p = eb->pages[i];
kaddr = page_address(p);
*map = kaddr + offset;
*map_len = PAGE_SIZE - offset;
return 0;
}
int memcmp_extent_buffer(const 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 = offset_in_page(eb->start);
unsigned long i = (start_offset + start) >> PAGE_SHIFT;
int ret = 0;
WARN_ON(start > eb->len);
WARN_ON(start + len > eb->start + eb->len);
offset = offset_in_page(start_offset + start);
while (len > 0) {
page = eb->pages[i];
cur = min(len, (PAGE_SIZE - offset));
kaddr = page_address(page);
ret = memcmp(ptr, kaddr + offset, cur);
if (ret)
break;
ptr += cur;
len -= cur;
offset = 0;
i++;
}
return ret;
}
void write_extent_buffer_chunk_tree_uuid(struct extent_buffer *eb,
const void *srcv)
{
char *kaddr;
WARN_ON(!PageUptodate(eb->pages[0]));
kaddr = page_address(eb->pages[0]);
memcpy(kaddr + offsetof(struct btrfs_header, chunk_tree_uuid), srcv,
BTRFS_FSID_SIZE);
}
void write_extent_buffer_fsid(struct extent_buffer *eb, const void *srcv)
{
char *kaddr;
WARN_ON(!PageUptodate(eb->pages[0]));
kaddr = page_address(eb->pages[0]);
memcpy(kaddr + offsetof(struct btrfs_header, fsid), srcv,
BTRFS_FSID_SIZE);
}
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 = offset_in_page(eb->start);
unsigned long i = (start_offset + start) >> PAGE_SHIFT;
WARN_ON(start > eb->len);
WARN_ON(start + len > eb->start + eb->len);
offset = offset_in_page(start_offset + start);
while (len > 0) {
page = eb->pages[i];
WARN_ON(!PageUptodate(page));
cur = min(len, PAGE_SIZE - offset);
kaddr = page_address(page);
memcpy(kaddr + offset, src, cur);
src += cur;
len -= cur;
offset = 0;
i++;
}
}
void memzero_extent_buffer(struct extent_buffer *eb, unsigned long start,
unsigned long len)
{
size_t cur;
size_t offset;
struct page *page;
char *kaddr;
size_t start_offset = offset_in_page(eb->start);
unsigned long i = (start_offset + start) >> PAGE_SHIFT;
WARN_ON(start > eb->len);
WARN_ON(start + len > eb->start + eb->len);
offset = offset_in_page(start_offset + start);
while (len > 0) {
page = eb->pages[i];
WARN_ON(!PageUptodate(page));
cur = min(len, PAGE_SIZE - offset);
kaddr = page_address(page);
memset(kaddr + offset, 0, cur);
len -= cur;
offset = 0;
i++;
}
}
void copy_extent_buffer_full(struct extent_buffer *dst,
struct extent_buffer *src)
{
int i;
int num_pages;
ASSERT(dst->len == src->len);
num_pages = num_extent_pages(dst);
for (i = 0; i < num_pages; i++)
copy_page(page_address(dst->pages[i]),
page_address(src->pages[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 = offset_in_page(dst->start);
unsigned long i = (start_offset + dst_offset) >> PAGE_SHIFT;
WARN_ON(src->len != dst_len);
offset = offset_in_page(start_offset + dst_offset);
while (len > 0) {
page = dst->pages[i];
WARN_ON(!PageUptodate(page));
cur = min(len, (unsigned long)(PAGE_SIZE - offset));
kaddr = page_address(page);
read_extent_buffer(src, kaddr + offset, src_offset, cur);
src_offset += cur;
len -= cur;
offset = 0;
i++;
}
}
/*
* eb_bitmap_offset() - calculate the page and offset of the byte containing the
* given bit number
* @eb: the extent buffer
* @start: offset of the bitmap item in the extent buffer
* @nr: bit number
* @page_index: return index of the page in the extent buffer that contains the
* given bit number
* @page_offset: return offset into the page given by page_index
*
* This helper hides the ugliness of finding the byte in an extent buffer which
* contains a given bit.
*/
static inline void eb_bitmap_offset(struct extent_buffer *eb,
unsigned long start, unsigned long nr,
unsigned long *page_index,
size_t *page_offset)
{
size_t start_offset = offset_in_page(eb->start);
size_t byte_offset = BIT_BYTE(nr);
size_t offset;
/*
* The byte we want is the offset of the extent buffer + the offset of
* the bitmap item in the extent buffer + the offset of the byte in the
* bitmap item.
*/
offset = start_offset + start + byte_offset;
*page_index = offset >> PAGE_SHIFT;
*page_offset = offset_in_page(offset);
}
/**
* extent_buffer_test_bit - determine whether a bit in a bitmap item is set
* @eb: the extent buffer
* @start: offset of the bitmap item in the extent buffer
* @nr: bit number to test
*/
int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start,
unsigned long nr)
{
u8 *kaddr;
struct page *page;
unsigned long i;
size_t offset;
eb_bitmap_offset(eb, start, nr, &i, &offset);
page = eb->pages[i];
WARN_ON(!PageUptodate(page));
kaddr = page_address(page);
return 1U & (kaddr[offset] >> (nr & (BITS_PER_BYTE - 1)));
}
/**
* extent_buffer_bitmap_set - set an area of a bitmap
* @eb: the extent buffer
* @start: offset of the bitmap item in the extent buffer
* @pos: bit number of the first bit
* @len: number of bits to set
*/
void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start,
unsigned long pos, unsigned long len)
{
u8 *kaddr;
struct page *page;
unsigned long i;
size_t offset;
const unsigned int size = pos + len;
int bits_to_set = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(pos);
eb_bitmap_offset(eb, start, pos, &i, &offset);
page = eb->pages[i];
WARN_ON(!PageUptodate(page));
kaddr = page_address(page);
while (len >= bits_to_set) {
kaddr[offset] |= mask_to_set;
len -= bits_to_set;
bits_to_set = BITS_PER_BYTE;
mask_to_set = ~0;
if (++offset >= PAGE_SIZE && len > 0) {
offset = 0;
page = eb->pages[++i];
WARN_ON(!PageUptodate(page));
kaddr = page_address(page);
}
}
if (len) {
mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
kaddr[offset] |= mask_to_set;
}
}
/**
* extent_buffer_bitmap_clear - clear an area of a bitmap
* @eb: the extent buffer
* @start: offset of the bitmap item in the extent buffer
* @pos: bit number of the first bit
* @len: number of bits to clear
*/
void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start,
unsigned long pos, unsigned long len)
{
u8 *kaddr;
struct page *page;
unsigned long i;
size_t offset;
const unsigned int size = pos + len;
int bits_to_clear = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(pos);
eb_bitmap_offset(eb, start, pos, &i, &offset);
page = eb->pages[i];
WARN_ON(!PageUptodate(page));
kaddr = page_address(page);
while (len >= bits_to_clear) {
kaddr[offset] &= ~mask_to_clear;
len -= bits_to_clear;
bits_to_clear = BITS_PER_BYTE;
mask_to_clear = ~0;
if (++offset >= PAGE_SIZE && len > 0) {
offset = 0;
page = eb->pages[++i];
WARN_ON(!PageUptodate(page));
kaddr = page_address(page);
}
}
if (len) {
mask_to_clear &= BITMAP_LAST_BYTE_MASK(size);
kaddr[offset] &= ~mask_to_clear;
}
}
static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
{
unsigned long distance = (src > dst) ? src - dst : dst - src;
return distance < len;
}
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 = page_address(dst_page);
char *src_kaddr;
int must_memmove = 0;
if (dst_page != src_page) {
src_kaddr = page_address(src_page);
} else {
src_kaddr = dst_kaddr;
if (areas_overlap(src_off, dst_off, len))
must_memmove = 1;
}
if (must_memmove)
memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
else
memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
}
void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
unsigned long src_offset, unsigned long len)
{
struct btrfs_fs_info *fs_info = dst->fs_info;
size_t cur;
size_t dst_off_in_page;
size_t src_off_in_page;
size_t start_offset = offset_in_page(dst->start);
unsigned long dst_i;
unsigned long src_i;
if (src_offset + len > dst->len) {
btrfs_err(fs_info,
"memmove bogus src_offset %lu move len %lu dst len %lu",
src_offset, len, dst->len);
BUG();
}
if (dst_offset + len > dst->len) {
btrfs_err(fs_info,
"memmove bogus dst_offset %lu move len %lu dst len %lu",
dst_offset, len, dst->len);
BUG();
}
while (len > 0) {
dst_off_in_page = offset_in_page(start_offset + dst_offset);
src_off_in_page = offset_in_page(start_offset + src_offset);
dst_i = (start_offset + dst_offset) >> PAGE_SHIFT;
src_i = (start_offset + src_offset) >> PAGE_SHIFT;
cur = min(len, (unsigned long)(PAGE_SIZE -
src_off_in_page));
cur = min_t(unsigned long, cur,
(unsigned long)(PAGE_SIZE - dst_off_in_page));
copy_pages(dst->pages[dst_i], dst->pages[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)
{
struct btrfs_fs_info *fs_info = dst->fs_info;
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 = offset_in_page(dst->start);
unsigned long dst_i;
unsigned long src_i;
if (src_offset + len > dst->len) {
btrfs_err(fs_info,
"memmove bogus src_offset %lu move len %lu len %lu",
src_offset, len, dst->len);
BUG();
}
if (dst_offset + len > dst->len) {
btrfs_err(fs_info,
"memmove bogus dst_offset %lu move len %lu len %lu",
dst_offset, len, dst->len);
BUG();
}
if (dst_offset < src_offset) {
memcpy_extent_buffer(dst, dst_offset, src_offset, len);
return;
}
while (len > 0) {
dst_i = (start_offset + dst_end) >> PAGE_SHIFT;
src_i = (start_offset + src_end) >> PAGE_SHIFT;
dst_off_in_page = offset_in_page(start_offset + dst_end);
src_off_in_page = offset_in_page(start_offset + src_end);
cur = min_t(unsigned long, len, src_off_in_page + 1);
cur = min(cur, dst_off_in_page + 1);
copy_pages(dst->pages[dst_i], dst->pages[src_i],
dst_off_in_page - cur + 1,
src_off_in_page - cur + 1, cur);
dst_end -= cur;
src_end -= cur;
len -= cur;
}
}
int try_release_extent_buffer(struct page *page)
{
struct extent_buffer *eb;
/*
* We need to make sure nobody is attaching this page to an eb right
* now.
*/
spin_lock(&page->mapping->private_lock);
if (!PagePrivate(page)) {
spin_unlock(&page->mapping->private_lock);
return 1;
}
eb = (struct extent_buffer *)page->private;
BUG_ON(!eb);
/*
* This is a little awful but should be ok, we need to make sure that
* the eb doesn't disappear out from under us while we're looking at
* this page.
*/
spin_lock(&eb->refs_lock);
if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
spin_unlock(&eb->refs_lock);
spin_unlock(&page->mapping->private_lock);
return 0;
}
spin_unlock(&page->mapping->private_lock);
/*
* If tree ref isn't set then we know the ref on this eb is a real ref,
* so just return, this page will likely be freed soon anyway.
*/
if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
spin_unlock(&eb->refs_lock);
return 0;
}
return release_extent_buffer(eb);
}
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