diff options
Diffstat (limited to '')
| -rw-r--r-- | fs/btrfs/extent_io.c | 6139 |
1 files changed, 6139 insertions, 0 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c new file mode 100644 index 000000000..685a375bb --- /dev/null +++ b/fs/btrfs/extent_io.c @@ -0,0 +1,6139 @@ +// 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(states); +static DEFINE_SPINLOCK(leak_lock); + +static inline void btrfs_leak_debug_add(spinlock_t *lock, + struct list_head *new, + struct list_head *head) +{ + unsigned long flags; + + spin_lock_irqsave(lock, flags); + list_add(new, head); + spin_unlock_irqrestore(lock, flags); +} + +static inline void btrfs_leak_debug_del(spinlock_t *lock, + struct list_head *entry) +{ + unsigned long flags; + + spin_lock_irqsave(lock, flags); + list_del(entry); + spin_unlock_irqrestore(lock, flags); +} + +void btrfs_extent_buffer_leak_debug_check(struct btrfs_fs_info *fs_info) +{ + struct extent_buffer *eb; + unsigned long flags; + + /* + * If we didn't get into open_ctree our allocated_ebs will not be + * initialized, so just skip this. + */ + if (!fs_info->allocated_ebs.next) + return; + + spin_lock_irqsave(&fs_info->eb_leak_lock, flags); + while (!list_empty(&fs_info->allocated_ebs)) { + eb = list_first_entry(&fs_info->allocated_ebs, + struct extent_buffer, leak_list); + pr_err( + "BTRFS: buffer leak start %llu len %lu refs %d bflags %lu owner %llu\n", + eb->start, eb->len, atomic_read(&eb->refs), eb->bflags, + btrfs_header_owner(eb)); + list_del(&eb->leak_list); + kmem_cache_free(extent_buffer_cache, eb); + } + spin_unlock_irqrestore(&fs_info->eb_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 || !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(lock, new, head) do {} while (0) +#define btrfs_leak_debug_del(lock, entry) 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; + /* 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; +} + +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 (is_data_inode(tree->private_data)) + ret = btrfs_submit_data_bio(tree->private_data, bio, mirror_num, + bio_flags); + else + ret = btrfs_submit_metadata_bio(tree->private_data, bio, + mirror_num, bio_flags); + + 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) +{ + /* + * 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->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(&leak_lock, &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(&leak_lock, &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) +{ + btrfs_panic(tree->fs_info, 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; + } + + /* + * 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. + */ + 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]); + for (; i < ret; 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 btrfs_inode *inode, u64 start, u64 end, + struct page *locked_page, + unsigned clear_bits, + unsigned long page_ops) +{ + clear_extent_bit(&inode->io_tree, start, end, clear_bits, 1, 0, NULL); + + __process_pages_contig(inode->vfs_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; +} + +struct io_failure_record *get_state_failrec(struct extent_io_tree *tree, u64 start) +{ + struct rb_node *node; + struct extent_state *state; + struct io_failure_record *failrec; + + spin_lock(&tree->lock); + /* + * this search will find all the extents that end after + * our range starts. + */ + node = tree_search(tree, start); + if (!node) { + failrec = ERR_PTR(-ENOENT); + goto out; + } + state = rb_entry(node, struct extent_state, rb_node); + if (state->start != start) { + failrec = ERR_PTR(-ENOENT); + goto out; + } + + failrec = state->failrec; +out: + spin_unlock(&tree->lock); + return failrec; +} + +/* + * 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(const 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; + + failrec = get_state_failrec(failure_tree, start); + if (IS_ERR(failrec)) + 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); +} + +static struct io_failure_record *btrfs_get_io_failure_record(struct inode *inode, + u64 start, u64 end) +{ + 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; + + failrec = get_state_failrec(failure_tree, start); + if (!IS_ERR(failrec)) { + 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. + */ + + return failrec; + } + + failrec = kzalloc(sizeof(*failrec), GFP_NOFS); + if (!failrec) + return ERR_PTR(-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 ERR_PTR(-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 ERR_PTR(-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 */ + ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED); + } else if (ret < 0) { + kfree(failrec); + return ERR_PTR(ret); + } + + return failrec; +} + +static bool btrfs_check_repairable(struct inode *inode, bool needs_validation, + 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 (needs_validation) { + /* + * 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; +} + +static bool btrfs_io_needs_validation(struct inode *inode, struct bio *bio) +{ + u64 len = 0; + const u32 blocksize = inode->i_sb->s_blocksize; + + /* + * If bi_status is BLK_STS_OK, then this was a checksum error, not an + * I/O error. In this case, we already know exactly which sector was + * bad, so we don't need to validate. + */ + if (bio->bi_status == BLK_STS_OK) + return false; + + /* + * We need to validate each sector individually if the failed I/O was + * for multiple sectors. + * + * There are a few possible bios that can end up here: + * 1. A buffered read bio, which is not cloned. + * 2. A direct I/O read bio, which is cloned. + * 3. A (buffered or direct) repair bio, which is not cloned. + * + * For cloned bios (case 2), we can get the size from + * btrfs_io_bio->iter; for non-cloned bios (cases 1 and 3), we can get + * it from the bvecs. + */ + if (bio_flagged(bio, BIO_CLONED)) { + if (btrfs_io_bio(bio)->iter.bi_size > blocksize) + return true; + } else { + struct bio_vec *bvec; + int i; + + bio_for_each_bvec_all(bvec, bio, i) { + len += bvec->bv_len; + if (len > blocksize) + return true; + } + } + return false; +} + +blk_status_t btrfs_submit_read_repair(struct inode *inode, + struct bio *failed_bio, u64 phy_offset, + struct page *page, unsigned int pgoff, + u64 start, u64 end, int failed_mirror, + submit_bio_hook_t *submit_bio_hook) +{ + struct io_failure_record *failrec; + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree; + struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree; + struct btrfs_io_bio *failed_io_bio = btrfs_io_bio(failed_bio); + const int icsum = phy_offset >> inode->i_sb->s_blocksize_bits; + bool need_validation; + struct bio *repair_bio; + struct btrfs_io_bio *repair_io_bio; + blk_status_t status; + + btrfs_debug(fs_info, + "repair read error: read error at %llu", start); + + BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE); + + failrec = btrfs_get_io_failure_record(inode, start, end); + if (IS_ERR(failrec)) + return errno_to_blk_status(PTR_ERR(failrec)); + + need_validation = btrfs_io_needs_validation(inode, failed_bio); + + if (!btrfs_check_repairable(inode, need_validation, failrec, + failed_mirror)) { + free_io_failure(failure_tree, tree, failrec); + return BLK_STS_IOERR; + } + + repair_bio = btrfs_io_bio_alloc(1); + repair_io_bio = btrfs_io_bio(repair_bio); + repair_bio->bi_opf = REQ_OP_READ; + if (need_validation) + repair_bio->bi_opf |= REQ_FAILFAST_DEV; + repair_bio->bi_end_io = failed_bio->bi_end_io; + repair_bio->bi_iter.bi_sector = failrec->logical >> 9; + repair_bio->bi_private = failed_bio->bi_private; + + if (failed_io_bio->csum) { + const u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); + + repair_io_bio->csum = repair_io_bio->csum_inline; + memcpy(repair_io_bio->csum, + failed_io_bio->csum + csum_size * icsum, csum_size); + } + + bio_add_page(repair_bio, page, failrec->len, pgoff); + repair_io_bio->logical = failrec->start; + repair_io_bio->iter = repair_bio->bi_iter; + + btrfs_debug(btrfs_sb(inode->i_sb), +"repair read error: submitting new read to mirror %d, in_validation=%d", + failrec->this_mirror, failrec->in_validation); + + status = submit_bio_hook(inode, repair_bio, failrec->this_mirror, + failrec->bio_flags); + if (status) { + free_io_failure(failure_tree, tree, failrec); + bio_put(repair_bio); + } + return status; +} + +/* 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); + + 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)) { + if (is_data_inode(inode)) + ret = btrfs_verify_data_csum(io_bio, offset, page, + start, end, mirror); + else + ret = btrfs_validate_metadata_buffer(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 (is_data_inode(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. + */ + if (!btrfs_submit_read_repair(inode, bio, offset, page, + start - page_offset(page), + start, end, mirror, + btrfs_submit_data_bio)) { + 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 + * @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 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; + struct extent_io_tree *tree = &BTRFS_I(page->mapping->host)->io_tree; + + 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; + + 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)) + attach_page_private(page, eb); + else + WARN_ON(page->private != (unsigned long)eb); +} + +void set_page_extent_mapped(struct page *page) +{ + if (!PagePrivate(page)) + attach_page_private(page, (void *)EXTENT_PAGE_PRIVATE); +} + +static struct extent_map * +__get_extent_map(struct inode *inode, struct page *page, size_t pg_offset, + u64 start, u64 len, 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 = btrfs_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 + */ +int btrfs_do_readpage(struct page *page, struct extent_map **em_cached, + struct bio **bio, 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; + struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree; + + 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, 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 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, NULL, + page, offset, disk_io_size, + pg_offset, bio, + end_bio_extent_readpage, 0, + *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 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(inode, start, end, NULL); + + for (index = 0; index < nr_pages; index++) { + btrfs_do_readpage(pages[index], em_cached, bio, bio_flags, + REQ_RAHEAD, prev_em_start); + put_page(pages[index]); + } +} + +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 btrfs_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->vfs_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. + */ + return ret < 0 ? ret : -EIO; + } + /* + * 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; + } + + return 0; +} + +/* + * 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 btrfs_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 = &inode->io_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->vfs_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(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(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, 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(BTRFS_I(inode), page, wbc, start, + &nr_written); + if (ret == 1) + return 0; + if (ret) + goto done; + } + + ret = __extent_writepage_io(BTRFS_I(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; + + /* + * A read may stumble upon this buffer later, make sure that it gets an + * error and knows there was an error. + */ + clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags); + + /* + * 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) +{ + 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, 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_buffer *eb, *prev_eb = NULL; + struct extent_page_data epd = { + .bio = NULL, + .extent_locked = 0, + .sync_io = wbc->sync_mode == WB_SYNC_ALL, + }; + struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info; + 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->sync_mode == WB_SYNC_NONE && + 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; + } + /* + * If something went wrong, don't allow any metadata write bio to be + * submitted. + * + * This would prevent use-after-free if we had dirty pages not + * cleaned up, which can still happen by fuzzed images. + * + * - Bad extent tree + * Allowing existing tree block to be allocated for other trees. + * + * - Log tree operations + * Exiting tree blocks get allocated to log tree, bumps its + * generation, then get cleaned in tree re-balance. + * Such tree block will not be written back, since it's clean, + * thus no WRITTEN flag set. + * And after log writes back, this tree block is not traced by + * any dirty extent_io_tree. + * + * - Offending tree block gets re-dirtied from its original owner + * Since it has bumped generation, no WRITTEN flag, it can be + * reused without COWing. This tree block will not be traced + * by btrfs_transaction::dirty_pages. + * + * Now such dirty tree block will not be cleaned by any dirty + * extent io tree. Thus we don't want to submit such wild eb + * if the fs already has error. + */ + if (!test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) { + ret = flush_write_bio(&epd); + } else { + ret = -EROFS; + end_write_bio(&epd, ret); + } + 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, + .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 page *page; + unsigned long nr_pages = (end - start + PAGE_SIZE) >> + PAGE_SHIFT; + + struct extent_page_data epd = { + .bio = NULL, + .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, + .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; +} + +void extent_readahead(struct readahead_control *rac) +{ + struct bio *bio = NULL; + unsigned long bio_flags = 0; + struct page *pagepool[16]; + struct extent_map *em_cached = NULL; + u64 prev_em_start = (u64)-1; + int nr; + + while ((nr = readahead_page_batch(rac, pagepool))) { + u64 contig_start = page_offset(pagepool[0]); + u64 contig_end = page_offset(pagepool[nr - 1]) + PAGE_SIZE - 1; + + ASSERT(contig_start + nr * PAGE_SIZE - 1 == contig_end); + + contiguous_readpages(pagepool, nr, contig_start, contig_end, + &em_cached, &bio, &bio_flags, &prev_em_start); + } + + if (em_cached) + free_extent_map(em_cached); + + if (bio) { + if (submit_one_bio(bio, 0, bio_flags)) + return; + } +} + +/* + * 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) { + struct btrfs_fs_info *fs_info; + u64 cur_gen; + + 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)) + goto next; + /* + * If it's not in the list of modified extents, used + * by a fast fsync, we can remove it. If it's being + * logged we can safely remove it since fsync took an + * extra reference on the em. + */ + if (list_empty(&em->list) || + test_bit(EXTENT_FLAG_LOGGING, &em->flags)) + goto remove_em; + /* + * If it's in the list of modified extents, remove it + * only if its generation is older then the current one, + * in which case we don't need it for a fast fsync. + * Otherwise don't remove it, we could be racing with an + * ongoing fast fsync that could miss the new extent. + */ + fs_info = btrfs_inode->root->fs_info; + spin_lock(&fs_info->trans_lock); + cur_gen = fs_info->generation; + spin_unlock(&fs_info->trans_lock); + if (em->generation >= cur_gen) + goto next; +remove_em: + /* + * We only remove extent maps that are not in the list of + * modified extents or that are in the list but with a + * generation lower then the current generation, so there + * is no need to set the full fsync flag on the inode (it + * hurts the fsync performance for workloads with a data + * size that exceeds or is close to the system's memory). + */ + remove_extent_mapping(map, em); + /* once for the rb tree */ + free_extent_map(em); +next: + start = extent_map_end(em); + write_unlock(&map->lock); + + /* once for us */ + free_extent_map(em); + + cond_resched(); /* Allow large-extent preemption. */ + } + } + 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 btrfs_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(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 btrfs_inode *inode, struct fiemap_extent_info *fieinfo, + u64 start, u64 len) +{ + int ret = 0; + u64 off; + 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->vfs_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 = 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; + } + + /* + * We can't initialize that to 'start' as this could miss extents due + * to extent item merging + */ + off = 0; + 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(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(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(&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(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(&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) +{ + kmem_cache_free(extent_buffer_cache, eb); +} + +int extent_buffer_under_io(const 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. + */ + detach_page_private(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); + btrfs_leak_debug_del(&eb->fs_info->eb_leak_lock, &eb->leak_list); + __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_recursed = false; + init_waitqueue_head(&eb->write_lock_wq); + init_waitqueue_head(&eb->read_lock_wq); + + btrfs_leak_debug_add(&fs_info->eb_leak_lock, &eb->leak_list, + &fs_info->allocated_ebs); + + 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(const 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 TREE_REF bit is first set when the extent_buffer is added + * to the radix tree. It is also reset, if unset, when a new reference + * is created by find_extent_buffer. + * + * It is only cleared in two cases: freeing the last non-tree + * reference to the extent_buffer when its STALE bit is set or + * calling releasepage when the tree reference is the only reference. + * + * In both cases, care is taken to ensure that the extent_buffer's + * pages are not under io. However, releasepage can be concurrently + * called with creating new references, which is prone to race + * conditions between the calls to check_buffer_tree_ref in those + * codepaths and clearing TREE_REF in try_release_extent_buffer. + * + * The actual lifetime of the extent_buffer in the radix tree is + * adequately protected by the refcount, but the TREE_REF bit and + * its corresponding reference are not. To protect against this + * class of races, we call check_buffer_tree_ref from the codepaths + * which trigger io after they set eb->io_pages. Note that once io is + * initiated, TREE_REF can no longer be cleared, so that is the + * moment at which any such race is best fixed. + */ + 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) + __releases(&eb->refs_lock) +{ + 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); + } + + btrfs_leak_debug_del(&eb->fs_info->eb_leak_lock, &eb->leak_list); + /* 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(const 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; + + 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); + /* + * It is possible for releasepage to clear the TREE_REF bit before we + * set io_pages. See check_buffer_tree_ref for a more detailed comment. + */ + check_buffer_tree_ref(eb); + 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 = submit_extent_page(REQ_OP_READ | REQ_META, NULL, + page, page_offset(page), PAGE_SIZE, 0, + &bio, end_bio_extent_readpage, + mirror_num, 0, 0, false); + if (err) { + /* + * We failed to submit the bio so it's the + * caller's responsibility to perform cleanup + * i.e unlock page/set error bit. + */ + ret = err; + SetPageError(page); + unlock_page(page); + 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; +} + +static bool report_eb_range(const struct extent_buffer *eb, unsigned long start, + unsigned long len) +{ + btrfs_warn(eb->fs_info, + "access to eb bytenr %llu len %lu out of range start %lu len %lu", + eb->start, eb->len, start, len); + WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG)); + + return true; +} + +/* + * Check if the [start, start + len) range is valid before reading/writing + * the eb. + * NOTE: @start and @len are offset inside the eb, not logical address. + * + * Caller should not touch the dst/src memory if this function returns error. + */ +static inline int check_eb_range(const struct extent_buffer *eb, + unsigned long start, unsigned long len) +{ + unsigned long offset; + + /* start, start + len should not go beyond eb->len nor overflow */ + if (unlikely(check_add_overflow(start, len, &offset) || offset > eb->len)) + return report_eb_range(eb, start, len); + + return false; +} + +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; + unsigned long i = start >> PAGE_SHIFT; + + if (check_eb_range(eb, start, len)) { + /* + * Invalid range hit, reset the memory, so callers won't get + * some random garbage for their uninitialzed memory. + */ + memset(dstv, 0, len); + return; + } + + offset = offset_in_page(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_nofault(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; + unsigned long i = start >> PAGE_SHIFT; + int ret = 0; + + WARN_ON(start > eb->len); + WARN_ON(start + len > eb->start + eb->len); + + offset = offset_in_page(start); + + while (len > 0) { + page = eb->pages[i]; + + cur = min(len, (PAGE_SIZE - offset)); + kaddr = page_address(page); + if (copy_to_user_nofault(dst, kaddr + offset, cur)) { + ret = -EFAULT; + break; + } + + dst += cur; + len -= cur; + offset = 0; + i++; + } + + return ret; +} + +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; + unsigned long i = start >> PAGE_SHIFT; + int ret = 0; + + if (check_eb_range(eb, start, len)) + return -EINVAL; + + offset = offset_in_page(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(const 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(const 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(const 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; + unsigned long i = start >> PAGE_SHIFT; + + if (check_eb_range(eb, start, len)) + return; + + offset = offset_in_page(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(const struct extent_buffer *eb, unsigned long start, + unsigned long len) +{ + size_t cur; + size_t offset; + struct page *page; + char *kaddr; + unsigned long i = start >> PAGE_SHIFT; + + if (check_eb_range(eb, start, len)) + return; + + offset = offset_in_page(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(const struct extent_buffer *dst, + const 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(const struct extent_buffer *dst, + const 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; + unsigned long i = dst_offset >> PAGE_SHIFT; + + if (check_eb_range(dst, dst_offset, len) || + check_eb_range(src, src_offset, len)) + return; + + WARN_ON(src->len != dst_len); + + offset = offset_in_page(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(const struct extent_buffer *eb, + unsigned long start, unsigned long nr, + unsigned long *page_index, + size_t *page_offset) +{ + 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 + 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(const 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(const 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(const 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(const struct extent_buffer *dst, + unsigned long dst_offset, unsigned long src_offset, + unsigned long len) +{ + size_t cur; + size_t dst_off_in_page; + size_t src_off_in_page; + unsigned long dst_i; + unsigned long src_i; + + if (check_eb_range(dst, dst_offset, len) || + check_eb_range(dst, src_offset, len)) + return; + + while (len > 0) { + dst_off_in_page = offset_in_page(dst_offset); + src_off_in_page = offset_in_page(src_offset); + + dst_i = dst_offset >> PAGE_SHIFT; + src_i = 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(const struct extent_buffer *dst, + unsigned long dst_offset, unsigned long src_offset, + unsigned long len) +{ + size_t cur; + size_t dst_off_in_page; + size_t src_off_in_page; + unsigned long dst_end = dst_offset + len - 1; + unsigned long src_end = src_offset + len - 1; + unsigned long dst_i; + unsigned long src_i; + + if (check_eb_range(dst, dst_offset, len) || + check_eb_range(dst, src_offset, len)) + return; + if (dst_offset < src_offset) { + memcpy_extent_buffer(dst, dst_offset, src_offset, len); + return; + } + while (len > 0) { + dst_i = dst_end >> PAGE_SHIFT; + src_i = src_end >> PAGE_SHIFT; + + dst_off_in_page = offset_in_page(dst_end); + src_off_in_page = offset_in_page(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); +} |