linuxdebug/fs/btrfs/extent-io-tree.c

1681 lines
42 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/slab.h>
#include <trace/events/btrfs.h>
#include "ctree.h"
#include "extent-io-tree.h"
#include "btrfs_inode.h"
#include "misc.h"
static struct kmem_cache *extent_state_cache;
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(states);
static DEFINE_SPINLOCK(leak_lock);
static inline void btrfs_leak_debug_add_state(struct extent_state *state)
{
unsigned long flags;
spin_lock_irqsave(&leak_lock, flags);
list_add(&state->leak_list, &states);
spin_unlock_irqrestore(&leak_lock, flags);
}
static inline void btrfs_leak_debug_del_state(struct extent_state *state)
{
unsigned long flags;
spin_lock_irqsave(&leak_lock, flags);
list_del(&state->leak_list);
spin_unlock_irqrestore(&leak_lock, flags);
}
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)
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_state(state) do {} while (0)
#define btrfs_leak_debug_del_state(state) 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
/*
* 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;
struct tree_entry {
u64 start;
u64 end;
struct rb_node rb_node;
};
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;
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;
RB_CLEAR_NODE(&state->rb_node);
btrfs_leak_debug_add_state(state);
refcount_set(&state->refs, 1);
init_waitqueue_head(&state->wq);
trace_alloc_extent_state(state, mask, _RET_IP_);
return state;
}
static struct extent_state *alloc_extent_state_atomic(struct extent_state *prealloc)
{
if (!prealloc)
prealloc = alloc_extent_state(GFP_ATOMIC);
return prealloc;
}
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(state);
trace_free_extent_state(state, _RET_IP_);
kmem_cache_free(extent_state_cache, state);
}
}
static int add_extent_changeset(struct extent_state *state, u32 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 inline 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;
}
static inline struct extent_state *prev_state(struct extent_state *state)
{
struct rb_node *next = rb_prev(&state->rb_node);
if (next)
return rb_entry(next, struct extent_state, rb_node);
else
return NULL;
}
/*
* Search @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
* @node_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
*
* Return a pointer to the entry that contains @offset byte address and don't change
* @node_ret and @parent_ret.
*
* If no such entry exists, return pointer to entry that ends before @offset
* and fill parameters @node_ret and @parent_ret, ie. does not return NULL.
*/
static inline struct extent_state *tree_search_for_insert(struct extent_io_tree *tree,
u64 offset,
struct rb_node ***node_ret,
struct rb_node **parent_ret)
{
struct rb_root *root = &tree->state;
struct rb_node **node = &root->rb_node;
struct rb_node *prev = NULL;
struct extent_state *entry = NULL;
while (*node) {
prev = *node;
entry = rb_entry(prev, struct extent_state, rb_node);
if (offset < entry->start)
node = &(*node)->rb_left;
else if (offset > entry->end)
node = &(*node)->rb_right;
else
return entry;
}
if (node_ret)
*node_ret = node;
if (parent_ret)
*parent_ret = prev;
/* Search neighbors until we find the first one past the end */
while (entry && offset > entry->end)
entry = next_state(entry);
return entry;
}
/*
* Search offset in the tree or fill neighbor rbtree node pointers.
*
* @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_ret: pointer to the first entry whose range begins before @offset
*
* Return a pointer to the entry that contains @offset byte address. If no
* such entry exists, then return NULL and fill @prev_ret and @next_ret.
* Otherwise return the found entry and other pointers are left untouched.
*/
static struct extent_state *tree_search_prev_next(struct extent_io_tree *tree,
u64 offset,
struct extent_state **prev_ret,
struct extent_state **next_ret)
{
struct rb_root *root = &tree->state;
struct rb_node **node = &root->rb_node;
struct extent_state *orig_prev;
struct extent_state *entry = NULL;
ASSERT(prev_ret);
ASSERT(next_ret);
while (*node) {
entry = rb_entry(*node, struct extent_state, rb_node);
if (offset < entry->start)
node = &(*node)->rb_left;
else if (offset > entry->end)
node = &(*node)->rb_right;
else
return entry;
}
orig_prev = entry;
while (entry && offset > entry->end)
entry = next_state(entry);
*next_ret = entry;
entry = orig_prev;
while (entry && offset < entry->start)
entry = prev_state(entry);
*prev_ret = entry;
return NULL;
}
/*
* Inexact rb-tree search, return the next entry if @offset is not found
*/
static inline struct extent_state *tree_search(struct extent_io_tree *tree, u64 offset)
{
return tree_search_for_insert(tree, offset, NULL, NULL);
}
static void extent_io_tree_panic(struct extent_io_tree *tree, int err)
{
btrfs_panic(tree->fs_info, err,
"locking error: extent tree was modified by another thread while locked");
}
/*
* 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;
if (state->state & (EXTENT_LOCKED | EXTENT_BOUNDARY))
return;
other = prev_state(state);
if (other && other->end == state->start - 1 &&
other->state == state->state) {
if (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 = next_state(state);
if (other && other->start == state->end + 1 &&
other->state == state->state) {
if (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,
u32 bits, struct extent_changeset *changeset)
{
u32 bits_to_set = bits & ~EXTENT_CTLBITS;
int ret;
if (tree->private_data)
btrfs_set_delalloc_extent(tree->private_data, state, bits);
ret = add_extent_changeset(state, bits_to_set, changeset, 1);
BUG_ON(ret < 0);
state->state |= bits_to_set;
}
/*
* 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,
u32 bits, struct extent_changeset *changeset)
{
struct rb_node **node;
struct rb_node *parent = NULL;
const u64 end = state->end;
set_state_bits(tree, state, bits, changeset);
node = &tree->state.rb_node;
while (*node) {
struct extent_state *entry;
parent = *node;
entry = rb_entry(parent, struct extent_state, rb_node);
if (end < entry->start) {
node = &(*node)->rb_left;
} else if (end > entry->end) {
node = &(*node)->rb_right;
} else {
btrfs_err(tree->fs_info,
"found node %llu %llu on insert of %llu %llu",
entry->start, entry->end, state->start, end);
return -EEXIST;
}
}
rb_link_node(&state->rb_node, parent, node);
rb_insert_color(&state->rb_node, &tree->state);
merge_state(tree, state);
return 0;
}
/*
* Insert state to @tree to the location given by @node and @parent.
*/
static void insert_state_fast(struct extent_io_tree *tree,
struct extent_state *state, struct rb_node **node,
struct rb_node *parent, unsigned bits,
struct extent_changeset *changeset)
{
set_state_bits(tree, state, bits, changeset);
rb_link_node(&state->rb_node, parent, node);
rb_insert_color(&state->rb_node, &tree->state);
merge_state(tree, state);
}
/*
* 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 *parent = NULL;
struct rb_node **node;
if (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;
parent = &orig->rb_node;
node = &parent;
while (*node) {
struct extent_state *entry;
parent = *node;
entry = rb_entry(parent, struct extent_state, rb_node);
if (prealloc->end < entry->start) {
node = &(*node)->rb_left;
} else if (prealloc->end > entry->end) {
node = &(*node)->rb_right;
} else {
free_extent_state(prealloc);
return -EEXIST;
}
}
rb_link_node(&prealloc->rb_node, parent, node);
rb_insert_color(&prealloc->rb_node, &tree->state);
return 0;
}
/*
* 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,
u32 bits, int wake,
struct extent_changeset *changeset)
{
struct extent_state *next;
u32 bits_to_clear = bits & ~EXTENT_CTLBITS;
int ret;
if (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;
}
/*
* 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,
u32 bits, 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;
u64 last_end;
int err;
int clear = 0;
int wake;
int delete = (bits & EXTENT_CLEAR_ALL_BITS);
btrfs_debug_check_extent_io_range(tree, start, end);
trace_btrfs_clear_extent_bit(tree, start, end - start + 1, bits);
if (delete)
bits |= ~EXTENT_CTLBITS;
if (bits & EXTENT_DELALLOC)
bits |= EXTENT_NORESERVE;
wake = (bits & EXTENT_LOCKED) ? 1 : 0;
if (bits & (EXTENT_LOCKED | EXTENT_BOUNDARY))
clear = 1;
again:
if (!prealloc) {
/*
* 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. */
state = tree_search(tree, start);
if (!state)
goto out;
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);
if (!prealloc)
goto search_again;
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);
if (!prealloc)
goto search_again;
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);
}
/*
* Wait 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
*/
void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, u32 bits)
{
struct extent_state *state;
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.
*/
state = tree_search(tree, start);
process_node:
if (!state)
break;
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)) {
state = next_state(state);
goto process_node;
}
}
out:
spin_unlock(&tree->lock);
}
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);
}
/*
* 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, u32 bits)
{
struct extent_state *state;
/*
* This search will find all the extents that end after our range
* starts.
*/
state = tree_search(tree, start);
while (state) {
if (state->end >= start && (state->state & bits))
return state;
state = next_state(state);
}
return NULL;
}
/*
* Find the first offset in the io tree with one or more @bits set.
*
* Note: If there are multiple bits set in @bits, any of them will match.
*
* Return 0 if we find something, and update @start_ret and @end_ret.
* Return 1 if we found nothing.
*/
int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
u64 *start_ret, u64 *end_ret, u32 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 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, u32 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 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 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.
*/
state = tree_search(tree, cur_start);
if (!state) {
*end = (u64)-1;
goto out;
}
while (state) {
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;
total_bytes += state->end - state->start + 1;
if (total_bytes >= max_bytes)
break;
state = next_state(state);
}
out:
spin_unlock(&tree->lock);
return found;
}
/*
* 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 __set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
u32 bits, u64 *failed_start,
struct extent_state **cached_state,
struct extent_changeset *changeset, gfp_t mask)
{
struct extent_state *state;
struct extent_state *prealloc = NULL;
struct rb_node **p;
struct rb_node *parent;
int err = 0;
u64 last_start;
u64 last_end;
u32 exclusive_bits = (bits & EXTENT_LOCKED);
btrfs_debug_check_extent_io_range(tree, start, end);
trace_btrfs_set_extent_bit(tree, start, end - start + 1, bits);
if (exclusive_bits)
ASSERT(failed_start);
else
ASSERT(failed_start == NULL);
again:
if (!prealloc) {
/*
* 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))
goto hit_next;
}
/*
* This search will find all the extents that end after our range
* starts.
*/
state = tree_search_for_insert(tree, start, &p, &parent);
if (!state) {
prealloc = alloc_extent_state_atomic(prealloc);
if (!prealloc)
goto search_again;
prealloc->start = start;
prealloc->end = end;
insert_state_fast(tree, prealloc, p, parent, bits, changeset);
cache_state(prealloc, cached_state);
prealloc = NULL;
goto out;
}
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;
}
/*
* If this extent already has all the bits we want set, then
* skip it, not necessary to split it or do anything with it.
*/
if ((state->state & bits) == bits) {
start = state->end + 1;
cache_state(state, cached_state);
goto search_again;
}
prealloc = alloc_extent_state_atomic(prealloc);
if (!prealloc)
goto search_again;
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);
if (!prealloc)
goto search_again;
/*
* Avoid to free 'prealloc' if it can be merged with the later
* extent.
*/
prealloc->start = start;
prealloc->end = this_end;
err = insert_state(tree, prealloc, 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);
if (!prealloc)
goto search_again;
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,
u32 bits, struct extent_state **cached_state, gfp_t mask)
{
return __set_extent_bit(tree, start, end, bits, NULL, cached_state,
NULL, mask);
}
/*
* 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,
u32 bits, u32 clear_bits,
struct extent_state **cached_state)
{
struct extent_state *state;
struct extent_state *prealloc = NULL;
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))
goto hit_next;
}
/*
* This search will find all the extents that end after our range
* starts.
*/
state = tree_search_for_insert(tree, start, &p, &parent);
if (!state) {
prealloc = alloc_extent_state_atomic(prealloc);
if (!prealloc) {
err = -ENOMEM;
goto out;
}
prealloc->start = start;
prealloc->end = end;
insert_state_fast(tree, prealloc, p, parent, bits, NULL);
cache_state(prealloc, cached_state);
prealloc = NULL;
goto out;
}
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.
*/
prealloc->start = start;
prealloc->end = this_end;
err = insert_state(tree, prealloc, 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;
}
/*
* Find the first range that has @bits not set. This range could start before
* @start.
*
* @tree: the tree to search
* @start: 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, u32 bits)
{
struct extent_state *state;
struct extent_state *prev = NULL, *next;
spin_lock(&tree->lock);
/* Find first extent with bits cleared */
while (1) {
state = tree_search_prev_next(tree, start, &prev, &next);
if (!state && !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 (!state && !next) {
/*
* We are past the last allocated chunk, set start at
* the end of the last extent.
*/
*start_ret = prev->end + 1;
*end_ret = -1;
goto out;
} else if (!state) {
state = next;
}
/*
* At this point 'state' either contains 'start' or start is
* before 'state'
*/
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)
*start_ret = prev->end + 1;
else
*start_ret = 0;
break;
}
}
/*
* Find the longest stretch from start until an entry which has the
* bits set
*/
while (state) {
if (state->end >= start && !(state->state & bits)) {
*end_ret = state->end;
} else {
*end_ret = state->start - 1;
break;
}
state = next_state(state);
}
out:
spin_unlock(&tree->lock);
}
/*
* 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,
u32 bits, int contig)
{
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);
/*
* This search will find all the extents that end after our range
* starts.
*/
state = tree_search(tree, cur_start);
while (state) {
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;
}
state = next_state(state);
}
spin_unlock(&tree->lock);
return total_bytes;
}
/*
* Searche 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,
u32 bits, int filled, struct extent_state *cached)
{
struct extent_state *state = NULL;
int bitset = 0;
spin_lock(&tree->lock);
if (cached && extent_state_in_tree(cached) && cached->start <= start &&
cached->end > start)
state = cached;
else
state = tree_search(tree, start);
while (state && start <= end) {
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;
state = next_state(state);
}
/* We ran out of states and were still inside of our range. */
if (filled && !state)
bitset = 0;
spin_unlock(&tree->lock);
return bitset;
}
/* Wrappers around set/clear extent bit */
int set_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
u32 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.
*/
ASSERT(!(bits & EXTENT_LOCKED));
return __set_extent_bit(tree, start, end, bits, NULL, NULL, changeset,
GFP_NOFS);
}
int clear_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
u32 bits, struct extent_changeset *changeset)
{
/*
* Don't support EXTENT_LOCKED case, same reason as
* set_record_extent_bits().
*/
ASSERT(!(bits & EXTENT_LOCKED));
return __clear_extent_bit(tree, start, end, bits, NULL, GFP_NOFS,
changeset);
}
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, &failed_start,
NULL, NULL, GFP_NOFS);
if (err == -EEXIST) {
if (failed_start > start)
clear_extent_bit(tree, start, failed_start - 1,
EXTENT_LOCKED, NULL);
return 0;
}
return 1;
}
/*
* Either insert or lock state struct between start and end use mask to tell
* us if waiting is desired.
*/
int lock_extent(struct extent_io_tree *tree, u64 start, u64 end,
struct extent_state **cached_state)
{
int err;
u64 failed_start;
err = __set_extent_bit(tree, start, end, EXTENT_LOCKED, &failed_start,
cached_state, NULL, GFP_NOFS);
while (err == -EEXIST) {
if (failed_start != start)
clear_extent_bit(tree, start, failed_start - 1,
EXTENT_LOCKED, cached_state);
wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
err = __set_extent_bit(tree, start, end, EXTENT_LOCKED,
&failed_start, cached_state, NULL,
GFP_NOFS);
}
return err;
}
void __cold extent_state_free_cachep(void)
{
btrfs_extent_state_leak_debug_check();
kmem_cache_destroy(extent_state_cache);
}
int __init extent_state_init_cachep(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;
}