diff options
Diffstat (limited to 'fs/btrfs/extent-io-tree.c')
| -rw-r--r-- | fs/btrfs/extent-io-tree.c | 1674 |
1 files changed, 1674 insertions, 0 deletions
diff --git a/fs/btrfs/extent-io-tree.c b/fs/btrfs/extent-io-tree.c new file mode 100644 index 000000000000..83cb0378096f --- /dev/null +++ b/fs/btrfs/extent-io-tree.c @@ -0,0 +1,1674 @@ +// 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; + 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 && 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. */ + 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); + 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); +} + +/* + * 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 && 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)) + 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); + BUG_ON(!prealloc); + 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); + 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. + */ + 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); + 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, + 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; +} |