diff options
Diffstat (limited to 'ANDROID_3.4.5/fs/btrfs/extent_io.c')
| -rw-r--r-- | ANDROID_3.4.5/fs/btrfs/extent_io.c | 4891 |
1 files changed, 4891 insertions, 0 deletions
diff --git a/ANDROID_3.4.5/fs/btrfs/extent_io.c b/ANDROID_3.4.5/fs/btrfs/extent_io.c new file mode 100644 index 00000000..c9018a05 --- /dev/null +++ b/ANDROID_3.4.5/fs/btrfs/extent_io.c @@ -0,0 +1,4891 @@ +#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/module.h> +#include <linux/spinlock.h> +#include <linux/blkdev.h> +#include <linux/swap.h> +#include <linux/writeback.h> +#include <linux/pagevec.h> +#include <linux/prefetch.h> +#include <linux/cleancache.h> +#include "extent_io.h" +#include "extent_map.h" +#include "compat.h" +#include "ctree.h" +#include "btrfs_inode.h" +#include "volumes.h" +#include "check-integrity.h" +#include "locking.h" + +static struct kmem_cache *extent_state_cache; +static struct kmem_cache *extent_buffer_cache; + +static LIST_HEAD(buffers); +static LIST_HEAD(states); + +#define LEAK_DEBUG 0 +#if LEAK_DEBUG +static DEFINE_SPINLOCK(leak_lock); +#endif + +#define BUFFER_LRU_MAX 64 + +struct tree_entry { + u64 start; + u64 end; + struct rb_node rb_node; +}; + +struct extent_page_data { + struct bio *bio; + struct extent_io_tree *tree; + get_extent_t *get_extent; + + /* tells writepage not to lock the state bits for this range + * it still does the unlocking + */ + unsigned int extent_locked:1; + + /* tells the submit_bio code to use a WRITE_SYNC */ + unsigned int sync_io:1; +}; + +static noinline void flush_write_bio(void *data); +static inline struct btrfs_fs_info * +tree_fs_info(struct extent_io_tree *tree) +{ + return btrfs_sb(tree->mapping->host->i_sb); +} + +int __init extent_io_init(void) +{ + extent_state_cache = kmem_cache_create("extent_state", + sizeof(struct extent_state), 0, + SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL); + if (!extent_state_cache) + return -ENOMEM; + + extent_buffer_cache = kmem_cache_create("extent_buffers", + sizeof(struct extent_buffer), 0, + SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL); + if (!extent_buffer_cache) + goto free_state_cache; + return 0; + +free_state_cache: + kmem_cache_destroy(extent_state_cache); + return -ENOMEM; +} + +void extent_io_exit(void) +{ + struct extent_state *state; + struct extent_buffer *eb; + + while (!list_empty(&states)) { + state = list_entry(states.next, struct extent_state, leak_list); + printk(KERN_ERR "btrfs state leak: start %llu end %llu " + "state %lu in tree %p refs %d\n", + (unsigned long long)state->start, + (unsigned long long)state->end, + state->state, state->tree, atomic_read(&state->refs)); + list_del(&state->leak_list); + kmem_cache_free(extent_state_cache, state); + + } + + while (!list_empty(&buffers)) { + eb = list_entry(buffers.next, struct extent_buffer, leak_list); + printk(KERN_ERR "btrfs buffer leak start %llu len %lu " + "refs %d\n", (unsigned long long)eb->start, + eb->len, atomic_read(&eb->refs)); + list_del(&eb->leak_list); + kmem_cache_free(extent_buffer_cache, eb); + } + if (extent_state_cache) + kmem_cache_destroy(extent_state_cache); + if (extent_buffer_cache) + kmem_cache_destroy(extent_buffer_cache); +} + +void extent_io_tree_init(struct extent_io_tree *tree, + struct address_space *mapping) +{ + tree->state = RB_ROOT; + INIT_RADIX_TREE(&tree->buffer, GFP_ATOMIC); + tree->ops = NULL; + tree->dirty_bytes = 0; + spin_lock_init(&tree->lock); + spin_lock_init(&tree->buffer_lock); + tree->mapping = mapping; +} + +static struct extent_state *alloc_extent_state(gfp_t mask) +{ + struct extent_state *state; +#if LEAK_DEBUG + unsigned long flags; +#endif + + state = kmem_cache_alloc(extent_state_cache, mask); + if (!state) + return state; + state->state = 0; + state->private = 0; + state->tree = NULL; +#if LEAK_DEBUG + spin_lock_irqsave(&leak_lock, flags); + list_add(&state->leak_list, &states); + spin_unlock_irqrestore(&leak_lock, flags); +#endif + atomic_set(&state->refs, 1); + init_waitqueue_head(&state->wq); + trace_alloc_extent_state(state, mask, _RET_IP_); + return state; +} + +void free_extent_state(struct extent_state *state) +{ + if (!state) + return; + if (atomic_dec_and_test(&state->refs)) { +#if LEAK_DEBUG + unsigned long flags; +#endif + WARN_ON(state->tree); +#if LEAK_DEBUG + spin_lock_irqsave(&leak_lock, flags); + list_del(&state->leak_list); + spin_unlock_irqrestore(&leak_lock, flags); +#endif + trace_free_extent_state(state, _RET_IP_); + kmem_cache_free(extent_state_cache, state); + } +} + +static struct rb_node *tree_insert(struct rb_root *root, u64 offset, + struct rb_node *node) +{ + struct rb_node **p = &root->rb_node; + struct rb_node *parent = NULL; + struct tree_entry *entry; + + while (*p) { + parent = *p; + entry = rb_entry(parent, struct tree_entry, rb_node); + + if (offset < entry->start) + p = &(*p)->rb_left; + else if (offset > entry->end) + p = &(*p)->rb_right; + else + return parent; + } + + entry = rb_entry(node, struct tree_entry, rb_node); + rb_link_node(node, parent, p); + rb_insert_color(node, root); + return NULL; +} + +static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset, + struct rb_node **prev_ret, + struct rb_node **next_ret) +{ + struct rb_root *root = &tree->state; + struct rb_node *n = root->rb_node; + struct rb_node *prev = NULL; + struct rb_node *orig_prev = NULL; + struct tree_entry *entry; + struct tree_entry *prev_entry = NULL; + + while (n) { + entry = rb_entry(n, struct tree_entry, rb_node); + prev = n; + prev_entry = entry; + + if (offset < entry->start) + n = n->rb_left; + else if (offset > entry->end) + n = n->rb_right; + else + return n; + } + + if (prev_ret) { + orig_prev = prev; + while (prev && offset > prev_entry->end) { + prev = rb_next(prev); + prev_entry = rb_entry(prev, struct tree_entry, rb_node); + } + *prev_ret = prev; + prev = orig_prev; + } + + if (next_ret) { + prev_entry = rb_entry(prev, struct tree_entry, rb_node); + while (prev && offset < prev_entry->start) { + prev = rb_prev(prev); + prev_entry = rb_entry(prev, struct tree_entry, rb_node); + } + *next_ret = prev; + } + return NULL; +} + +static inline struct rb_node *tree_search(struct extent_io_tree *tree, + u64 offset) +{ + struct rb_node *prev = NULL; + struct rb_node *ret; + + ret = __etree_search(tree, offset, &prev, NULL); + if (!ret) + return prev; + return ret; +} + +static void merge_cb(struct extent_io_tree *tree, struct extent_state *new, + struct extent_state *other) +{ + if (tree->ops && tree->ops->merge_extent_hook) + tree->ops->merge_extent_hook(tree->mapping->host, new, + other); +} + +/* + * utility function to look for merge candidates inside a given range. + * Any extents with matching state are merged together into a single + * extent in the tree. Extents with EXTENT_IO in their state field + * are not merged because the end_io handlers need to be able to do + * operations on them without sleeping (or doing allocations/splits). + * + * This should be called with the tree lock held. + */ +static void merge_state(struct extent_io_tree *tree, + struct extent_state *state) +{ + struct extent_state *other; + struct rb_node *other_node; + + if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY)) + return; + + other_node = rb_prev(&state->rb_node); + if (other_node) { + other = rb_entry(other_node, struct extent_state, rb_node); + if (other->end == state->start - 1 && + other->state == state->state) { + merge_cb(tree, state, other); + state->start = other->start; + other->tree = NULL; + rb_erase(&other->rb_node, &tree->state); + free_extent_state(other); + } + } + other_node = rb_next(&state->rb_node); + if (other_node) { + other = rb_entry(other_node, struct extent_state, rb_node); + if (other->start == state->end + 1 && + other->state == state->state) { + merge_cb(tree, state, other); + state->end = other->end; + other->tree = NULL; + rb_erase(&other->rb_node, &tree->state); + free_extent_state(other); + } + } +} + +static void set_state_cb(struct extent_io_tree *tree, + struct extent_state *state, int *bits) +{ + if (tree->ops && tree->ops->set_bit_hook) + tree->ops->set_bit_hook(tree->mapping->host, state, bits); +} + +static void clear_state_cb(struct extent_io_tree *tree, + struct extent_state *state, int *bits) +{ + if (tree->ops && tree->ops->clear_bit_hook) + tree->ops->clear_bit_hook(tree->mapping->host, state, bits); +} + +static void set_state_bits(struct extent_io_tree *tree, + struct extent_state *state, int *bits); + +/* + * insert an extent_state struct into the tree. 'bits' are set on the + * struct before it is inserted. + * + * This may return -EEXIST if the extent is already there, in which case the + * state struct is freed. + * + * The tree lock is not taken internally. This is a utility function and + * probably isn't what you want to call (see set/clear_extent_bit). + */ +static int insert_state(struct extent_io_tree *tree, + struct extent_state *state, u64 start, u64 end, + int *bits) +{ + struct rb_node *node; + + if (end < start) { + printk(KERN_ERR "btrfs end < start %llu %llu\n", + (unsigned long long)end, + (unsigned long long)start); + WARN_ON(1); + } + state->start = start; + state->end = end; + + set_state_bits(tree, state, bits); + + node = tree_insert(&tree->state, end, &state->rb_node); + if (node) { + struct extent_state *found; + found = rb_entry(node, struct extent_state, rb_node); + printk(KERN_ERR "btrfs found node %llu %llu on insert of " + "%llu %llu\n", (unsigned long long)found->start, + (unsigned long long)found->end, + (unsigned long long)start, (unsigned long long)end); + return -EEXIST; + } + state->tree = tree; + merge_state(tree, state); + return 0; +} + +static void split_cb(struct extent_io_tree *tree, struct extent_state *orig, + u64 split) +{ + if (tree->ops && tree->ops->split_extent_hook) + tree->ops->split_extent_hook(tree->mapping->host, orig, split); +} + +/* + * split a given extent state struct in two, inserting the preallocated + * struct 'prealloc' as the newly created second half. 'split' indicates an + * offset inside 'orig' where it should be split. + * + * Before calling, + * the tree has 'orig' at [orig->start, orig->end]. After calling, there + * are two extent state structs in the tree: + * prealloc: [orig->start, split - 1] + * orig: [ split, orig->end ] + * + * The tree locks are not taken by this function. They need to be held + * by the caller. + */ +static int split_state(struct extent_io_tree *tree, struct extent_state *orig, + struct extent_state *prealloc, u64 split) +{ + struct rb_node *node; + + split_cb(tree, orig, split); + + prealloc->start = orig->start; + prealloc->end = split - 1; + prealloc->state = orig->state; + orig->start = split; + + node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node); + if (node) { + free_extent_state(prealloc); + return -EEXIST; + } + prealloc->tree = tree; + return 0; +} + +static struct extent_state *next_state(struct extent_state *state) +{ + struct rb_node *next = rb_next(&state->rb_node); + if (next) + return rb_entry(next, struct extent_state, rb_node); + else + return NULL; +} + +/* + * utility function to clear some bits in an extent state struct. + * it will optionally wake up any one waiting on this state (wake == 1) + * + * If no bits are set on the state struct after clearing things, the + * struct is freed and removed from the tree + */ +static struct extent_state *clear_state_bit(struct extent_io_tree *tree, + struct extent_state *state, + int *bits, int wake) +{ + struct extent_state *next; + int bits_to_clear = *bits & ~EXTENT_CTLBITS; + + if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) { + u64 range = state->end - state->start + 1; + WARN_ON(range > tree->dirty_bytes); + tree->dirty_bytes -= range; + } + clear_state_cb(tree, state, bits); + state->state &= ~bits_to_clear; + if (wake) + wake_up(&state->wq); + if (state->state == 0) { + next = next_state(state); + if (state->tree) { + rb_erase(&state->rb_node, &tree->state); + state->tree = NULL; + free_extent_state(state); + } else { + WARN_ON(1); + } + } else { + merge_state(tree, state); + next = next_state(state); + } + return next; +} + +static struct extent_state * +alloc_extent_state_atomic(struct extent_state *prealloc) +{ + if (!prealloc) + prealloc = alloc_extent_state(GFP_ATOMIC); + + return prealloc; +} + +void extent_io_tree_panic(struct extent_io_tree *tree, int err) +{ + btrfs_panic(tree_fs_info(tree), err, "Locking error: " + "Extent tree was modified by another " + "thread while locked."); +} + +/* + * clear some bits on a range in the tree. This may require splitting + * or inserting elements in the tree, so the gfp mask is used to + * indicate which allocations or sleeping are allowed. + * + * pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove + * the given range from the tree regardless of state (ie for truncate). + * + * the range [start, end] is inclusive. + * + * This takes the tree lock, and returns 0 on success and < 0 on error. + */ +int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, + int bits, int wake, int delete, + struct extent_state **cached_state, + gfp_t mask) +{ + struct extent_state *state; + struct extent_state *cached; + struct extent_state *prealloc = NULL; + struct rb_node *node; + u64 last_end; + int err; + int clear = 0; + + if (delete) + bits |= ~EXTENT_CTLBITS; + bits |= EXTENT_FIRST_DELALLOC; + + if (bits & (EXTENT_IOBITS | EXTENT_BOUNDARY)) + clear = 1; +again: + if (!prealloc && (mask & __GFP_WAIT)) { + prealloc = alloc_extent_state(mask); + if (!prealloc) + return -ENOMEM; + } + + spin_lock(&tree->lock); + if (cached_state) { + cached = *cached_state; + + if (clear) { + *cached_state = NULL; + cached_state = NULL; + } + + if (cached && cached->tree && cached->start <= start && + cached->end > start) { + if (clear) + atomic_dec(&cached->refs); + state = cached; + goto hit_next; + } + if (clear) + free_extent_state(cached); + } + /* + * this search will find the extents that end after + * our range starts + */ + node = tree_search(tree, start); + if (!node) + goto out; + state = rb_entry(node, struct extent_state, rb_node); +hit_next: + if (state->start > end) + goto out; + WARN_ON(state->end < start); + last_end = state->end; + + /* the state doesn't have the wanted bits, go ahead */ + if (!(state->state & bits)) { + state = next_state(state); + goto next; + } + + /* + * | ---- desired range ---- | + * | state | or + * | ------------- state -------------- | + * + * We need to split the extent we found, and may flip + * bits on second half. + * + * If the extent we found extends past our range, we + * just split and search again. It'll get split again + * the next time though. + * + * If the extent we found is inside our range, we clear + * the desired bit on it. + */ + + if (state->start < start) { + prealloc = alloc_extent_state_atomic(prealloc); + BUG_ON(!prealloc); + err = split_state(tree, state, prealloc, start); + if (err) + extent_io_tree_panic(tree, err); + + prealloc = NULL; + if (err) + goto out; + if (state->end <= end) { + clear_state_bit(tree, state, &bits, wake); + if (last_end == (u64)-1) + goto out; + start = last_end + 1; + } + goto search_again; + } + /* + * | ---- desired range ---- | + * | state | + * We need to split the extent, and clear the bit + * on the first half + */ + if (state->start <= end && state->end > end) { + prealloc = alloc_extent_state_atomic(prealloc); + BUG_ON(!prealloc); + err = split_state(tree, state, prealloc, end + 1); + if (err) + extent_io_tree_panic(tree, err); + + if (wake) + wake_up(&state->wq); + + clear_state_bit(tree, prealloc, &bits, wake); + + prealloc = NULL; + goto out; + } + + state = clear_state_bit(tree, state, &bits, wake); +next: + if (last_end == (u64)-1) + goto out; + start = last_end + 1; + if (start <= end && state && !need_resched()) + goto hit_next; + goto search_again; + +out: + spin_unlock(&tree->lock); + if (prealloc) + free_extent_state(prealloc); + + return 0; + +search_again: + if (start > end) + goto out; + spin_unlock(&tree->lock); + if (mask & __GFP_WAIT) + cond_resched(); + goto again; +} + +static void wait_on_state(struct extent_io_tree *tree, + struct extent_state *state) + __releases(tree->lock) + __acquires(tree->lock) +{ + DEFINE_WAIT(wait); + prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE); + spin_unlock(&tree->lock); + schedule(); + spin_lock(&tree->lock); + finish_wait(&state->wq, &wait); +} + +/* + * waits for one or more bits to clear on a range in the state tree. + * The range [start, end] is inclusive. + * The tree lock is taken by this function + */ +void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits) +{ + struct extent_state *state; + struct rb_node *node; + + spin_lock(&tree->lock); +again: + while (1) { + /* + * this search will find all the extents that end after + * our range starts + */ + node = tree_search(tree, start); + if (!node) + break; + + state = rb_entry(node, struct extent_state, rb_node); + + if (state->start > end) + goto out; + + if (state->state & bits) { + start = state->start; + atomic_inc(&state->refs); + wait_on_state(tree, state); + free_extent_state(state); + goto again; + } + start = state->end + 1; + + if (start > end) + break; + + cond_resched_lock(&tree->lock); + } +out: + spin_unlock(&tree->lock); +} + +static void set_state_bits(struct extent_io_tree *tree, + struct extent_state *state, + int *bits) +{ + int bits_to_set = *bits & ~EXTENT_CTLBITS; + + set_state_cb(tree, state, bits); + if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) { + u64 range = state->end - state->start + 1; + tree->dirty_bytes += range; + } + state->state |= bits_to_set; +} + +static void cache_state(struct extent_state *state, + struct extent_state **cached_ptr) +{ + if (cached_ptr && !(*cached_ptr)) { + if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY)) { + *cached_ptr = state; + atomic_inc(&state->refs); + } + } +} + +static void uncache_state(struct extent_state **cached_ptr) +{ + if (cached_ptr && (*cached_ptr)) { + struct extent_state *state = *cached_ptr; + *cached_ptr = NULL; + free_extent_state(state); + } +} + +/* + * set some bits on a range in the tree. This may require allocations or + * sleeping, so the gfp mask is used to indicate what is allowed. + * + * If any of the exclusive bits are set, this will fail with -EEXIST if some + * part of the range already has the desired bits set. The start of the + * existing range is returned in failed_start in this case. + * + * [start, end] is inclusive This takes the tree lock. + */ + +static int __must_check +__set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, + int bits, int exclusive_bits, u64 *failed_start, + struct extent_state **cached_state, gfp_t mask) +{ + struct extent_state *state; + struct extent_state *prealloc = NULL; + struct rb_node *node; + int err = 0; + u64 last_start; + u64 last_end; + + bits |= EXTENT_FIRST_DELALLOC; +again: + if (!prealloc && (mask & __GFP_WAIT)) { + prealloc = alloc_extent_state(mask); + BUG_ON(!prealloc); + } + + spin_lock(&tree->lock); + if (cached_state && *cached_state) { + state = *cached_state; + if (state->start <= start && state->end > start && + state->tree) { + node = &state->rb_node; + goto hit_next; + } + } + /* + * this search will find all the extents that end after + * our range starts. + */ + node = tree_search(tree, start); + if (!node) { + prealloc = alloc_extent_state_atomic(prealloc); + BUG_ON(!prealloc); + err = insert_state(tree, prealloc, start, end, &bits); + if (err) + extent_io_tree_panic(tree, err); + + prealloc = NULL; + goto out; + } + state = rb_entry(node, struct extent_state, rb_node); +hit_next: + last_start = state->start; + last_end = state->end; + + /* + * | ---- desired range ---- | + * | state | + * + * Just lock what we found and keep going + */ + if (state->start == start && state->end <= end) { + struct rb_node *next_node; + if (state->state & exclusive_bits) { + *failed_start = state->start; + err = -EEXIST; + goto out; + } + + set_state_bits(tree, state, &bits); + + cache_state(state, cached_state); + merge_state(tree, state); + if (last_end == (u64)-1) + goto out; + + start = last_end + 1; + next_node = rb_next(&state->rb_node); + if (next_node && start < end && prealloc && !need_resched()) { + state = rb_entry(next_node, struct extent_state, + rb_node); + if (state->start == start) + goto hit_next; + } + goto search_again; + } + + /* + * | ---- desired range ---- | + * | state | + * or + * | ------------- state -------------- | + * + * We need to split the extent we found, and may flip bits on + * second half. + * + * If the extent we found extends past our + * range, we just split and search again. It'll get split + * again the next time though. + * + * If the extent we found is inside our range, we set the + * desired bit on it. + */ + if (state->start < start) { + if (state->state & exclusive_bits) { + *failed_start = start; + err = -EEXIST; + goto out; + } + + prealloc = alloc_extent_state_atomic(prealloc); + BUG_ON(!prealloc); + err = split_state(tree, state, prealloc, start); + if (err) + extent_io_tree_panic(tree, err); + + prealloc = NULL; + if (err) + goto out; + if (state->end <= end) { + set_state_bits(tree, state, &bits); + cache_state(state, cached_state); + merge_state(tree, state); + if (last_end == (u64)-1) + goto out; + start = last_end + 1; + } + goto search_again; + } + /* + * | ---- desired range ---- | + * | state | or | state | + * + * There's a hole, we need to insert something in it and + * ignore the extent we found. + */ + if (state->start > start) { + u64 this_end; + if (end < last_start) + this_end = end; + else + this_end = last_start - 1; + + prealloc = alloc_extent_state_atomic(prealloc); + BUG_ON(!prealloc); + + /* + * Avoid to free 'prealloc' if it can be merged with + * the later extent. + */ + err = insert_state(tree, prealloc, start, this_end, + &bits); + if (err) + extent_io_tree_panic(tree, err); + + cache_state(prealloc, cached_state); + prealloc = NULL; + start = this_end + 1; + goto search_again; + } + /* + * | ---- desired range ---- | + * | state | + * We need to split the extent, and set the bit + * on the first half + */ + if (state->start <= end && state->end > end) { + if (state->state & exclusive_bits) { + *failed_start = start; + err = -EEXIST; + goto out; + } + + prealloc = alloc_extent_state_atomic(prealloc); + BUG_ON(!prealloc); + err = split_state(tree, state, prealloc, end + 1); + if (err) + extent_io_tree_panic(tree, err); + + set_state_bits(tree, prealloc, &bits); + cache_state(prealloc, cached_state); + merge_state(tree, prealloc); + prealloc = NULL; + goto out; + } + + goto search_again; + +out: + spin_unlock(&tree->lock); + if (prealloc) + free_extent_state(prealloc); + + return err; + +search_again: + if (start > end) + goto out; + spin_unlock(&tree->lock); + if (mask & __GFP_WAIT) + cond_resched(); + goto again; +} + +int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits, + u64 *failed_start, struct extent_state **cached_state, + gfp_t mask) +{ + return __set_extent_bit(tree, start, end, bits, 0, failed_start, + cached_state, mask); +} + + +/** + * convert_extent - 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 + * @mask: the allocation mask + * + * This will go through and set bits for the given range. If any states exist + * already in this range they are set with the given bit and cleared of the + * clear_bits. This is only meant to be used by things that are mergeable, ie + * converting from say DELALLOC to DIRTY. This is not meant to be used with + * boundary bits like LOCK. + */ +int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, + int bits, int clear_bits, gfp_t mask) +{ + struct extent_state *state; + struct extent_state *prealloc = NULL; + struct rb_node *node; + int err = 0; + u64 last_start; + u64 last_end; + +again: + if (!prealloc && (mask & __GFP_WAIT)) { + prealloc = alloc_extent_state(mask); + if (!prealloc) + return -ENOMEM; + } + + spin_lock(&tree->lock); + /* + * this search will find all the extents that end after + * our range starts. + */ + node = tree_search(tree, start); + if (!node) { + prealloc = alloc_extent_state_atomic(prealloc); + if (!prealloc) { + err = -ENOMEM; + goto out; + } + err = insert_state(tree, prealloc, start, end, &bits); + prealloc = NULL; + if (err) + extent_io_tree_panic(tree, err); + goto out; + } + state = rb_entry(node, struct extent_state, rb_node); +hit_next: + last_start = state->start; + last_end = state->end; + + /* + * | ---- desired range ---- | + * | state | + * + * Just lock what we found and keep going + */ + if (state->start == start && state->end <= end) { + struct rb_node *next_node; + + set_state_bits(tree, state, &bits); + clear_state_bit(tree, state, &clear_bits, 0); + if (last_end == (u64)-1) + goto out; + + start = last_end + 1; + next_node = rb_next(&state->rb_node); + if (next_node && start < end && prealloc && !need_resched()) { + state = rb_entry(next_node, struct extent_state, + rb_node); + if (state->start == start) + 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); + clear_state_bit(tree, state, &clear_bits, 0); + if (last_end == (u64)-1) + goto out; + start = last_end + 1; + } + goto search_again; + } + /* + * | ---- desired range ---- | + * | state | or | state | + * + * There's a hole, we need to insert something in it and + * ignore the extent we found. + */ + if (state->start > start) { + u64 this_end; + if (end < last_start) + this_end = end; + else + this_end = last_start - 1; + + prealloc = alloc_extent_state_atomic(prealloc); + if (!prealloc) { + err = -ENOMEM; + goto out; + } + + /* + * Avoid to free 'prealloc' if it can be merged with + * the later extent. + */ + err = insert_state(tree, prealloc, start, this_end, + &bits); + if (err) + extent_io_tree_panic(tree, err); + 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); + clear_state_bit(tree, prealloc, &clear_bits, 0); + prealloc = NULL; + goto out; + } + + goto search_again; + +out: + spin_unlock(&tree->lock); + if (prealloc) + free_extent_state(prealloc); + + return err; + +search_again: + if (start > end) + goto out; + spin_unlock(&tree->lock); + if (mask & __GFP_WAIT) + cond_resched(); + goto again; +} + +/* wrappers around set/clear extent bit */ +int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end, + gfp_t mask) +{ + return set_extent_bit(tree, start, end, EXTENT_DIRTY, NULL, + NULL, mask); +} + +int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end, + int bits, gfp_t mask) +{ + return set_extent_bit(tree, start, end, bits, NULL, + NULL, mask); +} + +int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end, + int bits, gfp_t mask) +{ + return clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask); +} + +int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end, + struct extent_state **cached_state, gfp_t mask) +{ + return set_extent_bit(tree, start, end, + EXTENT_DELALLOC | EXTENT_UPTODATE, + NULL, cached_state, mask); +} + +int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end, + gfp_t mask) +{ + return clear_extent_bit(tree, start, end, + EXTENT_DIRTY | EXTENT_DELALLOC | + EXTENT_DO_ACCOUNTING, 0, 0, NULL, mask); +} + +int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end, + gfp_t mask) +{ + return set_extent_bit(tree, start, end, EXTENT_NEW, NULL, + NULL, mask); +} + +int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end, + struct extent_state **cached_state, gfp_t mask) +{ + return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, + cached_state, mask); +} + +static int clear_extent_uptodate(struct extent_io_tree *tree, u64 start, + u64 end, struct extent_state **cached_state, + gfp_t mask) +{ + return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0, + cached_state, mask); +} + +/* + * either insert or lock state struct between start and end use mask to tell + * us if waiting is desired. + */ +int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end, + int bits, struct extent_state **cached_state) +{ + int err; + u64 failed_start; + while (1) { + err = __set_extent_bit(tree, start, end, EXTENT_LOCKED | bits, + EXTENT_LOCKED, &failed_start, + cached_state, GFP_NOFS); + if (err == -EEXIST) { + wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED); + start = failed_start; + } else + break; + WARN_ON(start > end); + } + return err; +} + +int lock_extent(struct extent_io_tree *tree, u64 start, u64 end) +{ + return lock_extent_bits(tree, start, end, 0, NULL); +} + +int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end) +{ + int err; + u64 failed_start; + + err = __set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED, + &failed_start, NULL, GFP_NOFS); + if (err == -EEXIST) { + if (failed_start > start) + clear_extent_bit(tree, start, failed_start - 1, + EXTENT_LOCKED, 1, 0, NULL, GFP_NOFS); + return 0; + } + return 1; +} + +int unlock_extent_cached(struct extent_io_tree *tree, u64 start, u64 end, + struct extent_state **cached, gfp_t mask) +{ + return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached, + mask); +} + +int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end) +{ + return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL, + GFP_NOFS); +} + +/* + * helper function to set both pages and extents in the tree writeback + */ +static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end) +{ + unsigned long index = start >> PAGE_CACHE_SHIFT; + unsigned long end_index = end >> PAGE_CACHE_SHIFT; + struct page *page; + + while (index <= end_index) { + page = find_get_page(tree->mapping, index); + BUG_ON(!page); /* Pages should be in the extent_io_tree */ + set_page_writeback(page); + page_cache_release(page); + index++; + } + return 0; +} + +/* find the first state struct with 'bits' set after 'start', and + * return it. tree->lock must be held. NULL will returned if + * nothing was found after 'start' + */ +struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree, + u64 start, int 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, < 0 on error + */ +int find_first_extent_bit(struct extent_io_tree *tree, u64 start, + u64 *start_ret, u64 *end_ret, int 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; + ret = 0; + } + spin_unlock(&tree->lock); + return ret; +} + +/* + * find a contiguous range of bytes in the file marked as delalloc, not + * more than 'max_bytes'. start and end are used to return the range, + * + * 1 is returned if we find something, 0 if nothing was in the tree + */ +static noinline u64 find_delalloc_range(struct extent_io_tree *tree, + u64 *start, u64 *end, u64 max_bytes, + struct extent_state **cached_state) +{ + struct rb_node *node; + struct extent_state *state; + u64 cur_start = *start; + u64 found = 0; + u64 total_bytes = 0; + + spin_lock(&tree->lock); + + /* + * this search will find all the extents that end after + * our range starts. + */ + node = tree_search(tree, cur_start); + if (!node) { + if (!found) + *end = (u64)-1; + goto out; + } + + while (1) { + state = rb_entry(node, struct extent_state, rb_node); + if (found && (state->start != cur_start || + (state->state & EXTENT_BOUNDARY))) { + goto out; + } + if (!(state->state & EXTENT_DELALLOC)) { + if (!found) + *end = state->end; + goto out; + } + if (!found) { + *start = state->start; + *cached_state = state; + atomic_inc(&state->refs); + } + found++; + *end = state->end; + cur_start = state->end + 1; + node = rb_next(node); + if (!node) + break; + total_bytes += state->end - state->start + 1; + if (total_bytes >= max_bytes) + break; + } +out: + spin_unlock(&tree->lock); + return found; +} + +static noinline void __unlock_for_delalloc(struct inode *inode, + struct page *locked_page, + u64 start, u64 end) +{ + int ret; + struct page *pages[16]; + unsigned long index = start >> PAGE_CACHE_SHIFT; + unsigned long end_index = end >> PAGE_CACHE_SHIFT; + unsigned long nr_pages = end_index - index + 1; + int i; + + if (index == locked_page->index && end_index == index) + return; + + while (nr_pages > 0) { + ret = find_get_pages_contig(inode->i_mapping, index, + min_t(unsigned long, nr_pages, + ARRAY_SIZE(pages)), pages); + for (i = 0; i < ret; i++) { + if (pages[i] != locked_page) + unlock_page(pages[i]); + page_cache_release(pages[i]); + } + nr_pages -= ret; + index += ret; + cond_resched(); + } +} + +static noinline int lock_delalloc_pages(struct inode *inode, + struct page *locked_page, + u64 delalloc_start, + u64 delalloc_end) +{ + unsigned long index = delalloc_start >> PAGE_CACHE_SHIFT; + unsigned long start_index = index; + unsigned long end_index = delalloc_end >> PAGE_CACHE_SHIFT; + unsigned long pages_locked = 0; + struct page *pages[16]; + unsigned long nrpages; + int ret; + int i; + + /* the caller is responsible for locking the start index */ + if (index == locked_page->index && index == end_index) + return 0; + + /* skip the page at the start index */ + nrpages = end_index - index + 1; + while (nrpages > 0) { + ret = find_get_pages_contig(inode->i_mapping, index, + min_t(unsigned long, + nrpages, ARRAY_SIZE(pages)), pages); + if (ret == 0) { + ret = -EAGAIN; + goto done; + } + /* now we have an array of pages, lock them all */ + for (i = 0; i < ret; i++) { + /* + * the caller is taking responsibility for + * locked_page + */ + if (pages[i] != locked_page) { + lock_page(pages[i]); + if (!PageDirty(pages[i]) || + pages[i]->mapping != inode->i_mapping) { + ret = -EAGAIN; + unlock_page(pages[i]); + page_cache_release(pages[i]); + goto done; + } + } + page_cache_release(pages[i]); + pages_locked++; + } + nrpages -= ret; + index += ret; + cond_resched(); + } + ret = 0; +done: + if (ret && pages_locked) { + __unlock_for_delalloc(inode, locked_page, + delalloc_start, + ((u64)(start_index + pages_locked - 1)) << + PAGE_CACHE_SHIFT); + } + return ret; +} + +/* + * find a contiguous range of bytes in the file marked as delalloc, not + * more than 'max_bytes'. start and end are used to return the range, + * + * 1 is returned if we find something, 0 if nothing was in the tree + */ +static noinline u64 find_lock_delalloc_range(struct inode *inode, + struct extent_io_tree *tree, + struct page *locked_page, + u64 *start, u64 *end, + u64 max_bytes) +{ + u64 delalloc_start; + u64 delalloc_end; + u64 found; + struct extent_state *cached_state = NULL; + int ret; + int loops = 0; + +again: + /* step one, find a bunch of delalloc bytes starting at start */ + delalloc_start = *start; + delalloc_end = 0; + found = find_delalloc_range(tree, &delalloc_start, &delalloc_end, + max_bytes, &cached_state); + if (!found || delalloc_end <= *start) { + *start = delalloc_start; + *end = delalloc_end; + free_extent_state(cached_state); + return found; + } + + /* + * start comes from the offset of locked_page. We have to lock + * pages in order, so we can't process delalloc bytes before + * locked_page + */ + if (delalloc_start < *start) + delalloc_start = *start; + + /* + * make sure to limit the number of pages we try to lock down + * if we're looping. + */ + if (delalloc_end + 1 - delalloc_start > max_bytes && loops) + delalloc_end = delalloc_start + PAGE_CACHE_SIZE - 1; + + /* step two, lock all the pages after the page that has start */ + ret = lock_delalloc_pages(inode, locked_page, + delalloc_start, delalloc_end); + if (ret == -EAGAIN) { + /* some of the pages are gone, lets avoid looping by + * shortening the size of the delalloc range we're searching + */ + free_extent_state(cached_state); + if (!loops) { + unsigned long offset = (*start) & (PAGE_CACHE_SIZE - 1); + max_bytes = PAGE_CACHE_SIZE - offset; + loops = 1; + goto again; + } else { + found = 0; + goto out_failed; + } + } + BUG_ON(ret); /* Only valid values are 0 and -EAGAIN */ + + /* step three, lock the state bits for the whole range */ + lock_extent_bits(tree, delalloc_start, delalloc_end, 0, &cached_state); + + /* then test to make sure it is all still delalloc */ + ret = test_range_bit(tree, delalloc_start, delalloc_end, + EXTENT_DELALLOC, 1, cached_state); + if (!ret) { + unlock_extent_cached(tree, delalloc_start, delalloc_end, + &cached_state, GFP_NOFS); + __unlock_for_delalloc(inode, locked_page, + delalloc_start, delalloc_end); + cond_resched(); + goto again; + } + free_extent_state(cached_state); + *start = delalloc_start; + *end = delalloc_end; +out_failed: + return found; +} + +int extent_clear_unlock_delalloc(struct inode *inode, + struct extent_io_tree *tree, + u64 start, u64 end, struct page *locked_page, + unsigned long op) +{ + int ret; + struct page *pages[16]; + unsigned long index = start >> PAGE_CACHE_SHIFT; + unsigned long end_index = end >> PAGE_CACHE_SHIFT; + unsigned long nr_pages = end_index - index + 1; + int i; + int clear_bits = 0; + + if (op & EXTENT_CLEAR_UNLOCK) + clear_bits |= EXTENT_LOCKED; + if (op & EXTENT_CLEAR_DIRTY) + clear_bits |= EXTENT_DIRTY; + + if (op & EXTENT_CLEAR_DELALLOC) + clear_bits |= EXTENT_DELALLOC; + + clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS); + if (!(op & (EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY | + EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK | + EXTENT_SET_PRIVATE2))) + return 0; + + while (nr_pages > 0) { + ret = find_get_pages_contig(inode->i_mapping, index, + min_t(unsigned long, + nr_pages, ARRAY_SIZE(pages)), pages); + for (i = 0; i < ret; i++) { + + if (op & EXTENT_SET_PRIVATE2) + SetPagePrivate2(pages[i]); + + if (pages[i] == locked_page) { + page_cache_release(pages[i]); + continue; + } + if (op & EXTENT_CLEAR_DIRTY) + clear_page_dirty_for_io(pages[i]); + if (op & EXTENT_SET_WRITEBACK) + set_page_writeback(pages[i]); + if (op & EXTENT_END_WRITEBACK) + end_page_writeback(pages[i]); + if (op & EXTENT_CLEAR_UNLOCK_PAGE) + unlock_page(pages[i]); + page_cache_release(pages[i]); + } + nr_pages -= ret; + index += ret; + cond_resched(); + } + return 0; +} + +/* + * count the number of bytes in the tree that have a given bit(s) + * set. This can be fairly slow, except for EXTENT_DIRTY which is + * cached. The total number found is returned. + */ +u64 count_range_bits(struct extent_io_tree *tree, + u64 *start, u64 search_end, u64 max_bytes, + unsigned long bits, int contig) +{ + struct rb_node *node; + struct extent_state *state; + u64 cur_start = *start; + u64 total_bytes = 0; + u64 last = 0; + int found = 0; + + if (search_end <= cur_start) { + WARN_ON(1); + return 0; + } + + spin_lock(&tree->lock); + if (cur_start == 0 && bits == EXTENT_DIRTY) { + total_bytes = tree->dirty_bytes; + goto out; + } + /* + * this search will find all the extents that end after + * our range starts. + */ + node = tree_search(tree, cur_start); + if (!node) + goto out; + + while (1) { + state = rb_entry(node, struct extent_state, rb_node); + if (state->start > search_end) + break; + if (contig && found && state->start > last + 1) + break; + if (state->end >= cur_start && (state->state & bits) == bits) { + total_bytes += min(search_end, state->end) + 1 - + max(cur_start, state->start); + if (total_bytes >= max_bytes) + break; + if (!found) { + *start = max(cur_start, state->start); + found = 1; + } + last = state->end; + } else if (contig && found) { + break; + } + node = rb_next(node); + if (!node) + break; + } +out: + spin_unlock(&tree->lock); + return total_bytes; +} + +/* + * set the private field for a given byte offset in the tree. If there isn't + * an extent_state there already, this does nothing. + */ +int set_state_private(struct extent_io_tree *tree, u64 start, u64 private) +{ + struct rb_node *node; + struct extent_state *state; + int ret = 0; + + spin_lock(&tree->lock); + /* + * this search will find all the extents that end after + * our range starts. + */ + node = tree_search(tree, start); + if (!node) { + ret = -ENOENT; + goto out; + } + state = rb_entry(node, struct extent_state, rb_node); + if (state->start != start) { + ret = -ENOENT; + goto out; + } + state->private = private; +out: + spin_unlock(&tree->lock); + return ret; +} + +int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private) +{ + struct rb_node *node; + struct extent_state *state; + int ret = 0; + + spin_lock(&tree->lock); + /* + * this search will find all the extents that end after + * our range starts. + */ + node = tree_search(tree, start); + if (!node) { + ret = -ENOENT; + goto out; + } + state = rb_entry(node, struct extent_state, rb_node); + if (state->start != start) { + ret = -ENOENT; + goto out; + } + *private = state->private; +out: + spin_unlock(&tree->lock); + return ret; +} + +/* + * searches a range in the state tree for a given mask. + * If 'filled' == 1, this returns 1 only if every extent in the tree + * has the bits set. Otherwise, 1 is returned if any bit in the + * range is found set. + */ +int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end, + int bits, int filled, struct extent_state *cached) +{ + struct extent_state *state = NULL; + struct rb_node *node; + int bitset = 0; + + spin_lock(&tree->lock); + if (cached && cached->tree && cached->start <= start && + cached->end > start) + node = &cached->rb_node; + else + node = tree_search(tree, start); + while (node && start <= end) { + state = rb_entry(node, struct extent_state, rb_node); + + if (filled && state->start > start) { + bitset = 0; + break; + } + + if (state->start > end) + break; + + if (state->state & bits) { + bitset = 1; + if (!filled) + break; + } else if (filled) { + bitset = 0; + break; + } + + if (state->end == (u64)-1) + break; + + start = state->end + 1; + if (start > end) + break; + node = rb_next(node); + if (!node) { + if (filled) + bitset = 0; + break; + } + } + spin_unlock(&tree->lock); + return bitset; +} + +/* + * helper function to set a given page up to date if all the + * extents in the tree for that page are up to date + */ +static void check_page_uptodate(struct extent_io_tree *tree, struct page *page) +{ + u64 start = (u64)page->index << PAGE_CACHE_SHIFT; + u64 end = start + PAGE_CACHE_SIZE - 1; + if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL)) + SetPageUptodate(page); +} + +/* + * helper function to unlock a page if all the extents in the tree + * for that page are unlocked + */ +static void check_page_locked(struct extent_io_tree *tree, struct page *page) +{ + u64 start = (u64)page->index << PAGE_CACHE_SHIFT; + u64 end = start + PAGE_CACHE_SIZE - 1; + if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL)) + unlock_page(page); +} + +/* + * helper function to end page writeback if all the extents + * in the tree for that page are done with writeback + */ +static void check_page_writeback(struct extent_io_tree *tree, + struct page *page) +{ + end_page_writeback(page); +} + +/* + * When IO fails, either with EIO or csum verification fails, we + * try other mirrors that might have a good copy of the data. This + * io_failure_record is used to record state as we go through all the + * mirrors. If another mirror has good data, the page is set up to date + * and things continue. If a good mirror can't be found, the original + * bio end_io callback is called to indicate things have failed. + */ +struct io_failure_record { + struct page *page; + u64 start; + u64 len; + u64 logical; + unsigned long bio_flags; + int this_mirror; + int failed_mirror; + int in_validation; +}; + +static int free_io_failure(struct inode *inode, struct io_failure_record *rec, + int did_repair) +{ + int ret; + int err = 0; + struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree; + + set_state_private(failure_tree, rec->start, 0); + ret = clear_extent_bits(failure_tree, rec->start, + rec->start + rec->len - 1, + EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS); + if (ret) + err = ret; + + if (did_repair) { + ret = clear_extent_bits(&BTRFS_I(inode)->io_tree, rec->start, + rec->start + rec->len - 1, + EXTENT_DAMAGED, GFP_NOFS); + if (ret && !err) + err = ret; + } + + kfree(rec); + return err; +} + +static void repair_io_failure_callback(struct bio *bio, int err) +{ + complete(bio->bi_private); +} + +/* + * this bypasses the standard btrfs submit functions deliberately, as + * the standard behavior is to write all copies in a raid setup. here we only + * want to write the one bad copy. so we do the mapping for ourselves and issue + * submit_bio directly. + * to avoid any synchonization 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_mapping_tree *map_tree, u64 start, + u64 length, u64 logical, struct page *page, + int mirror_num) +{ + struct bio *bio; + struct btrfs_device *dev; + DECLARE_COMPLETION_ONSTACK(compl); + u64 map_length = 0; + u64 sector; + struct btrfs_bio *bbio = NULL; + int ret; + + BUG_ON(!mirror_num); + + bio = bio_alloc(GFP_NOFS, 1); + if (!bio) + return -EIO; + bio->bi_private = &compl; + bio->bi_end_io = repair_io_failure_callback; + bio->bi_size = 0; + map_length = length; + + ret = btrfs_map_block(map_tree, WRITE, logical, + &map_length, &bbio, mirror_num); + if (ret) { + bio_put(bio); + return -EIO; + } + BUG_ON(mirror_num != bbio->mirror_num); + sector = bbio->stripes[mirror_num-1].physical >> 9; + bio->bi_sector = sector; + dev = bbio->stripes[mirror_num-1].dev; + kfree(bbio); + if (!dev || !dev->bdev || !dev->writeable) { + bio_put(bio); + return -EIO; + } + bio->bi_bdev = dev->bdev; + bio_add_page(bio, page, length, start-page_offset(page)); + btrfsic_submit_bio(WRITE_SYNC, bio); + wait_for_completion(&compl); + + if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) { + /* try to remap that extent elsewhere? */ + bio_put(bio); + return -EIO; + } + + printk(KERN_INFO "btrfs read error corrected: ino %lu off %llu (dev %s " + "sector %llu)\n", page->mapping->host->i_ino, start, + dev->name, sector); + + bio_put(bio); + return 0; +} + +int repair_eb_io_failure(struct btrfs_root *root, struct extent_buffer *eb, + int mirror_num) +{ + struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree; + u64 start = eb->start; + unsigned long i, num_pages = num_extent_pages(eb->start, eb->len); + int ret = 0; + + for (i = 0; i < num_pages; i++) { + struct page *p = extent_buffer_page(eb, i); + ret = repair_io_failure(map_tree, start, PAGE_CACHE_SIZE, + start, p, mirror_num); + if (ret) + break; + start += PAGE_CACHE_SIZE; + } + + return ret; +} + +/* + * each time an IO finishes, we do a fast check in the IO failure tree + * to see if we need to process or clean up an io_failure_record + */ +static int clean_io_failure(u64 start, struct page *page) +{ + u64 private; + u64 private_failure; + struct io_failure_record *failrec; + struct btrfs_mapping_tree *map_tree; + struct extent_state *state; + int num_copies; + int did_repair = 0; + int ret; + struct inode *inode = page->mapping->host; + + private = 0; + ret = count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private, + (u64)-1, 1, EXTENT_DIRTY, 0); + if (!ret) + return 0; + + ret = get_state_private(&BTRFS_I(inode)->io_failure_tree, start, + &private_failure); + if (ret) + return 0; + + failrec = (struct io_failure_record *)(unsigned long) private_failure; + BUG_ON(!failrec->this_mirror); + + if (failrec->in_validation) { + /* there was no real error, just free the record */ + pr_debug("clean_io_failure: freeing dummy error at %llu\n", + failrec->start); + did_repair = 1; + goto out; + } + + spin_lock(&BTRFS_I(inode)->io_tree.lock); + state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree, + failrec->start, + EXTENT_LOCKED); + spin_unlock(&BTRFS_I(inode)->io_tree.lock); + + if (state && state->start == failrec->start) { + map_tree = &BTRFS_I(inode)->root->fs_info->mapping_tree; + num_copies = btrfs_num_copies(map_tree, failrec->logical, + failrec->len); + if (num_copies > 1) { + ret = repair_io_failure(map_tree, start, failrec->len, + failrec->logical, page, + failrec->failed_mirror); + did_repair = !ret; + } + } + +out: + if (!ret) + ret = free_io_failure(inode, failrec, did_repair); + + return ret; +} + +/* + * this is a generic handler for readpage errors (default + * readpage_io_failed_hook). if other copies exist, read those and write back + * good data to the failed position. does not investigate in remapping the + * failed extent elsewhere, hoping the device will be smart enough to do this as + * needed + */ + +static int bio_readpage_error(struct bio *failed_bio, struct page *page, + u64 start, u64 end, int failed_mirror, + struct extent_state *state) +{ + struct io_failure_record *failrec = NULL; + u64 private; + struct extent_map *em; + struct inode *inode = page->mapping->host; + struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree; + struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree; + struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; + struct bio *bio; + int num_copies; + int ret; + int read_mode; + u64 logical; + + BUG_ON(failed_bio->bi_rw & REQ_WRITE); + + ret = get_state_private(failure_tree, start, &private); + if (ret) { + failrec = kzalloc(sizeof(*failrec), GFP_NOFS); + if (!failrec) + return -ENOMEM; + failrec->start = start; + failrec->len = end - start + 1; + failrec->this_mirror = 0; + failrec->bio_flags = 0; + failrec->in_validation = 0; + + read_lock(&em_tree->lock); + em = lookup_extent_mapping(em_tree, start, failrec->len); + if (!em) { + read_unlock(&em_tree->lock); + kfree(failrec); + return -EIO; + } + + if (em->start > start || em->start + em->len < start) { + free_extent_map(em); + em = NULL; + } + read_unlock(&em_tree->lock); + + if (!em || IS_ERR(em)) { + kfree(failrec); + return -EIO; + } + logical = start - em->start; + logical = em->block_start + logical; + if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) { + logical = em->block_start; + failrec->bio_flags = EXTENT_BIO_COMPRESSED; + extent_set_compress_type(&failrec->bio_flags, + em->compress_type); + } + pr_debug("bio_readpage_error: (new) logical=%llu, start=%llu, " + "len=%llu\n", logical, start, failrec->len); + failrec->logical = logical; + free_extent_map(em); + + /* set the bits in the private failure tree */ + ret = set_extent_bits(failure_tree, start, end, + EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS); + if (ret >= 0) + ret = set_state_private(failure_tree, start, + (u64)(unsigned long)failrec); + /* set the bits in the inode's tree */ + if (ret >= 0) + ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED, + GFP_NOFS); + if (ret < 0) { + kfree(failrec); + return ret; + } + } else { + failrec = (struct io_failure_record *)(unsigned long)private; + pr_debug("bio_readpage_error: (found) logical=%llu, " + "start=%llu, len=%llu, validation=%d\n", + failrec->logical, failrec->start, failrec->len, + failrec->in_validation); + /* + * when data can be on disk more than twice, add to failrec here + * (e.g. with a list for failed_mirror) to make + * clean_io_failure() clean all those errors at once. + */ + } + num_copies = btrfs_num_copies( + &BTRFS_I(inode)->root->fs_info->mapping_tree, + failrec->logical, failrec->len); + if (num_copies == 1) { + /* + * we only have a single copy of the data, so don't bother with + * all the retry and error correction code that follows. no + * matter what the error is, it is very likely to persist. + */ + pr_debug("bio_readpage_error: cannot repair, num_copies == 1. " + "state=%p, num_copies=%d, next_mirror %d, " + "failed_mirror %d\n", state, num_copies, + failrec->this_mirror, failed_mirror); + free_io_failure(inode, failrec, 0); + return -EIO; + } + + if (!state) { + spin_lock(&tree->lock); + state = find_first_extent_bit_state(tree, failrec->start, + EXTENT_LOCKED); + if (state && state->start != failrec->start) + state = NULL; + spin_unlock(&tree->lock); + } + + /* + * there are two premises: + * a) deliver good data to the caller + * b) correct the bad sectors on disk + */ + if (failed_bio->bi_vcnt > 1) { + /* + * to fulfill b), we need to know the exact failing sectors, as + * we don't want to rewrite any more than the failed ones. thus, + * we need separate read requests for the failed bio + * + * if the following BUG_ON triggers, our validation request got + * merged. we need separate requests for our algorithm to work. + */ + BUG_ON(failrec->in_validation); + failrec->in_validation = 1; + failrec->this_mirror = failed_mirror; + read_mode = READ_SYNC | REQ_FAILFAST_DEV; + } else { + /* + * we're ready to fulfill a) and b) alongside. get a good copy + * of the failed sector and if we succeed, we have setup + * everything for repair_io_failure to do the rest for us. + */ + if (failrec->in_validation) { + BUG_ON(failrec->this_mirror != failed_mirror); + failrec->in_validation = 0; + failrec->this_mirror = 0; + } + failrec->failed_mirror = failed_mirror; + failrec->this_mirror++; + if (failrec->this_mirror == failed_mirror) + failrec->this_mirror++; + read_mode = READ_SYNC; + } + + if (!state || failrec->this_mirror > num_copies) { + pr_debug("bio_readpage_error: (fail) state=%p, num_copies=%d, " + "next_mirror %d, failed_mirror %d\n", state, + num_copies, failrec->this_mirror, failed_mirror); + free_io_failure(inode, failrec, 0); + return -EIO; + } + + bio = bio_alloc(GFP_NOFS, 1); + if (!bio) { + free_io_failure(inode, failrec, 0); + return -EIO; + } + bio->bi_private = state; + bio->bi_end_io = failed_bio->bi_end_io; + bio->bi_sector = failrec->logical >> 9; + bio->bi_bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; + bio->bi_size = 0; + + bio_add_page(bio, page, failrec->len, start - page_offset(page)); + + pr_debug("bio_readpage_error: submitting new read[%#x] to " + "this_mirror=%d, num_copies=%d, in_validation=%d\n", read_mode, + failrec->this_mirror, num_copies, failrec->in_validation); + + ret = tree->ops->submit_bio_hook(inode, read_mode, bio, + failrec->this_mirror, + failrec->bio_flags, 0); + return ret; +} + +/* lots and lots of room for performance fixes in the end_bio funcs */ + +int end_extent_writepage(struct page *page, int err, u64 start, u64 end) +{ + int uptodate = (err == 0); + struct extent_io_tree *tree; + int ret; + + tree = &BTRFS_I(page->mapping->host)->io_tree; + + if (tree->ops && tree->ops->writepage_end_io_hook) { + ret = tree->ops->writepage_end_io_hook(page, start, + end, NULL, uptodate); + if (ret) + uptodate = 0; + } + + if (!uptodate && tree->ops && + tree->ops->writepage_io_failed_hook) { + ret = tree->ops->writepage_io_failed_hook(NULL, page, + start, end, NULL); + /* Writeback already completed */ + if (ret == 0) + return 1; + } + + if (!uptodate) { + clear_extent_uptodate(tree, start, end, NULL, GFP_NOFS); + ClearPageUptodate(page); + SetPageError(page); + } + return 0; +} + +/* + * after a writepage IO is done, we need to: + * clear the uptodate bits on error + * clear the writeback bits in the extent tree for this IO + * end_page_writeback if the page has no more pending IO + * + * Scheduling is not allowed, so the extent state tree is expected + * to have one and only one object corresponding to this IO. + */ +static void end_bio_extent_writepage(struct bio *bio, int err) +{ + struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; + struct extent_io_tree *tree; + u64 start; + u64 end; + int whole_page; + + do { + struct page *page = bvec->bv_page; + tree = &BTRFS_I(page->mapping->host)->io_tree; + + start = ((u64)page->index << PAGE_CACHE_SHIFT) + + bvec->bv_offset; + end = start + bvec->bv_len - 1; + + if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE) + whole_page = 1; + else + whole_page = 0; + + if (--bvec >= bio->bi_io_vec) + prefetchw(&bvec->bv_page->flags); + + if (end_extent_writepage(page, err, start, end)) + continue; + + if (whole_page) + end_page_writeback(page); + else + check_page_writeback(tree, page); + } while (bvec >= bio->bi_io_vec); + + bio_put(bio); +} + +/* + * after a readpage IO is done, we need to: + * clear the uptodate bits on error + * set the uptodate bits if things worked + * set the page up to date if all extents in the tree are uptodate + * clear the lock bit in the extent tree + * unlock the page if there are no other extents locked for it + * + * Scheduling is not allowed, so the extent state tree is expected + * to have one and only one object corresponding to this IO. + */ +static void end_bio_extent_readpage(struct bio *bio, int err) +{ + int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); + struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1; + struct bio_vec *bvec = bio->bi_io_vec; + struct extent_io_tree *tree; + u64 start; + u64 end; + int whole_page; + int mirror; + int ret; + + if (err) + uptodate = 0; + + do { + struct page *page = bvec->bv_page; + struct extent_state *cached = NULL; + struct extent_state *state; + + pr_debug("end_bio_extent_readpage: bi_vcnt=%d, idx=%d, err=%d, " + "mirror=%ld\n", bio->bi_vcnt, bio->bi_idx, err, + (long int)bio->bi_bdev); + tree = &BTRFS_I(page->mapping->host)->io_tree; + + start = ((u64)page->index << PAGE_CACHE_SHIFT) + + bvec->bv_offset; + end = start + bvec->bv_len - 1; + + if (bvec->bv_offset == 0 && bvec->bv_len == PAGE_CACHE_SIZE) + whole_page = 1; + else + whole_page = 0; + + if (++bvec <= bvec_end) + prefetchw(&bvec->bv_page->flags); + + spin_lock(&tree->lock); + state = find_first_extent_bit_state(tree, start, EXTENT_LOCKED); + if (state && state->start == start) { + /* + * take a reference on the state, unlock will drop + * the ref + */ + cache_state(state, &cached); + } + spin_unlock(&tree->lock); + + mirror = (int)(unsigned long)bio->bi_bdev; + if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) { + ret = tree->ops->readpage_end_io_hook(page, start, end, + state, mirror); + if (ret) + uptodate = 0; + else + clean_io_failure(start, page); + } + + if (!uptodate && tree->ops && tree->ops->readpage_io_failed_hook) { + ret = tree->ops->readpage_io_failed_hook(page, mirror); + if (!ret && !err && + test_bit(BIO_UPTODATE, &bio->bi_flags)) + uptodate = 1; + } else if (!uptodate) { + /* + * The generic bio_readpage_error handles errors the + * following way: If possible, new read requests are + * created and submitted and will end up in + * end_bio_extent_readpage as well (if we're lucky, not + * in the !uptodate case). In that case it returns 0 and + * we just go on with the next page in our bio. If it + * can't handle the error it will return -EIO and we + * remain responsible for that page. + */ + ret = bio_readpage_error(bio, page, start, end, mirror, NULL); + if (ret == 0) { + uptodate = + test_bit(BIO_UPTODATE, &bio->bi_flags); + if (err) + uptodate = 0; + uncache_state(&cached); + continue; + } + } + + if (uptodate && tree->track_uptodate) { + set_extent_uptodate(tree, start, end, &cached, + GFP_ATOMIC); + } + unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC); + + if (whole_page) { + if (uptodate) { + SetPageUptodate(page); + } else { + ClearPageUptodate(page); + SetPageError(page); + } + unlock_page(page); + } else { + if (uptodate) { + check_page_uptodate(tree, page); + } else { + ClearPageUptodate(page); + SetPageError(page); + } + check_page_locked(tree, page); + } + } while (bvec <= bvec_end); + + bio_put(bio); +} + +struct bio * +btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs, + gfp_t gfp_flags) +{ + struct bio *bio; + + bio = bio_alloc(gfp_flags, nr_vecs); + + if (bio == NULL && (current->flags & PF_MEMALLOC)) { + while (!bio && (nr_vecs /= 2)) + bio = bio_alloc(gfp_flags, nr_vecs); + } + + if (bio) { + bio->bi_size = 0; + bio->bi_bdev = bdev; + bio->bi_sector = first_sector; + } + return bio; +} + +/* + * Since writes are async, they will only return -ENOMEM. + * Reads can return the full range of I/O error conditions. + */ +static int __must_check submit_one_bio(int rw, struct bio *bio, + int mirror_num, unsigned long bio_flags) +{ + int ret = 0; + struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; + struct page *page = bvec->bv_page; + struct extent_io_tree *tree = bio->bi_private; + u64 start; + + start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset; + + bio->bi_private = NULL; + + bio_get(bio); + + if (tree->ops && tree->ops->submit_bio_hook) + ret = tree->ops->submit_bio_hook(page->mapping->host, rw, bio, + mirror_num, bio_flags, start); + else + btrfsic_submit_bio(rw, bio); + + if (bio_flagged(bio, BIO_EOPNOTSUPP)) + ret = -EOPNOTSUPP; + bio_put(bio); + return ret; +} + +static int merge_bio(struct extent_io_tree *tree, struct page *page, + unsigned long offset, size_t size, struct bio *bio, + unsigned long bio_flags) +{ + int ret = 0; + if (tree->ops && tree->ops->merge_bio_hook) + ret = tree->ops->merge_bio_hook(page, offset, size, bio, + bio_flags); + BUG_ON(ret < 0); + return ret; + +} + +static int submit_extent_page(int rw, struct extent_io_tree *tree, + struct page *page, sector_t sector, + size_t size, unsigned long offset, + struct block_device *bdev, + struct bio **bio_ret, + unsigned long max_pages, + bio_end_io_t end_io_func, + int mirror_num, + unsigned long prev_bio_flags, + unsigned long bio_flags) +{ + int ret = 0; + struct bio *bio; + int nr; + int contig = 0; + int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED; + int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED; + size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE); + + if (bio_ret && *bio_ret) { + bio = *bio_ret; + if (old_compressed) + contig = bio->bi_sector == sector; + else + contig = bio->bi_sector + (bio->bi_size >> 9) == + sector; + + if (prev_bio_flags != bio_flags || !contig || + merge_bio(tree, page, offset, page_size, bio, bio_flags) || + bio_add_page(bio, page, page_size, offset) < page_size) { + ret = submit_one_bio(rw, bio, mirror_num, + prev_bio_flags); + if (ret < 0) + return ret; + bio = NULL; + } else { + return 0; + } + } + if (this_compressed) + nr = BIO_MAX_PAGES; + else + nr = bio_get_nr_vecs(bdev); + + bio = btrfs_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH); + if (!bio) + return -ENOMEM; + + bio_add_page(bio, page, page_size, offset); + bio->bi_end_io = end_io_func; + bio->bi_private = tree; + + if (bio_ret) + *bio_ret = bio; + else + ret = submit_one_bio(rw, bio, mirror_num, bio_flags); + + return ret; +} + +void attach_extent_buffer_page(struct extent_buffer *eb, struct page *page) +{ + if (!PagePrivate(page)) { + SetPagePrivate(page); + page_cache_get(page); + set_page_private(page, (unsigned long)eb); + } else { + WARN_ON(page->private != (unsigned long)eb); + } +} + +void set_page_extent_mapped(struct page *page) +{ + if (!PagePrivate(page)) { + SetPagePrivate(page); + page_cache_get(page); + set_page_private(page, EXTENT_PAGE_PRIVATE); + } +} + +/* + * basic readpage implementation. Locked extent state structs are inserted + * into the tree that are removed when the IO is done (by the end_io + * handlers) + * XXX JDM: This needs looking at to ensure proper page locking + */ +static int __extent_read_full_page(struct extent_io_tree *tree, + struct page *page, + get_extent_t *get_extent, + struct bio **bio, int mirror_num, + unsigned long *bio_flags) +{ + struct inode *inode = page->mapping->host; + u64 start = (u64)page->index << PAGE_CACHE_SHIFT; + u64 page_end = start + PAGE_CACHE_SIZE - 1; + u64 end; + u64 cur = start; + u64 extent_offset; + u64 last_byte = i_size_read(inode); + u64 block_start; + u64 cur_end; + sector_t sector; + struct extent_map *em; + struct block_device *bdev; + struct btrfs_ordered_extent *ordered; + int ret; + int nr = 0; + size_t pg_offset = 0; + size_t iosize; + size_t disk_io_size; + size_t blocksize = inode->i_sb->s_blocksize; + unsigned long this_bio_flag = 0; + + set_page_extent_mapped(page); + + if (!PageUptodate(page)) { + if (cleancache_get_page(page) == 0) { + BUG_ON(blocksize != PAGE_SIZE); + goto out; + } + } + + end = page_end; + while (1) { + lock_extent(tree, start, end); + ordered = btrfs_lookup_ordered_extent(inode, start); + if (!ordered) + break; + unlock_extent(tree, start, end); + btrfs_start_ordered_extent(inode, ordered, 1); + btrfs_put_ordered_extent(ordered); + } + + if (page->index == last_byte >> PAGE_CACHE_SHIFT) { + char *userpage; + size_t zero_offset = last_byte & (PAGE_CACHE_SIZE - 1); + + if (zero_offset) { + iosize = PAGE_CACHE_SIZE - zero_offset; + userpage = kmap_atomic(page); + memset(userpage + zero_offset, 0, iosize); + flush_dcache_page(page); + kunmap_atomic(userpage); + } + } + while (cur <= end) { + if (cur >= last_byte) { + char *userpage; + struct extent_state *cached = NULL; + + iosize = PAGE_CACHE_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, GFP_NOFS); + break; + } + em = get_extent(inode, page, pg_offset, cur, + end - cur + 1, 0); + 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 = (iosize + blocksize - 1) & ~((u64)blocksize - 1); + if (this_bio_flag & EXTENT_BIO_COMPRESSED) { + disk_io_size = em->block_len; + sector = em->block_start >> 9; + } else { + sector = (em->block_start + extent_offset) >> 9; + disk_io_size = iosize; + } + bdev = em->bdev; + block_start = em->block_start; + if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) + block_start = EXTENT_MAP_HOLE; + 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, GFP_NOFS); + 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 = 0; + if (tree->ops && tree->ops->readpage_io_hook) { + ret = tree->ops->readpage_io_hook(page, cur, + cur + iosize - 1); + } + if (!ret) { + unsigned long pnr = (last_byte >> PAGE_CACHE_SHIFT) + 1; + pnr -= page->index; + ret = submit_extent_page(READ, tree, page, + sector, disk_io_size, pg_offset, + bdev, bio, pnr, + end_bio_extent_readpage, mirror_num, + *bio_flags, + this_bio_flag); + BUG_ON(ret == -ENOMEM); + nr++; + *bio_flags = this_bio_flag; + } + if (ret) + SetPageError(page); + cur = cur + iosize; + pg_offset += iosize; + } +out: + if (!nr) { + if (!PageError(page)) + SetPageUptodate(page); + unlock_page(page); + } + return 0; +} + +int extent_read_full_page(struct extent_io_tree *tree, struct page *page, + get_extent_t *get_extent, int mirror_num) +{ + struct bio *bio = NULL; + unsigned long bio_flags = 0; + int ret; + + ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num, + &bio_flags); + if (bio) + ret = submit_one_bio(READ, bio, mirror_num, bio_flags); + return ret; +} + +static noinline void update_nr_written(struct page *page, + struct writeback_control *wbc, + unsigned long nr_written) +{ + wbc->nr_to_write -= nr_written; + if (wbc->range_cyclic || (wbc->nr_to_write > 0 && + wbc->range_start == 0 && wbc->range_end == LLONG_MAX)) + page->mapping->writeback_index = page->index + nr_written; +} + +/* + * 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 + */ +static int __extent_writepage(struct page *page, struct writeback_control *wbc, + void *data) +{ + struct inode *inode = page->mapping->host; + struct extent_page_data *epd = data; + struct extent_io_tree *tree = epd->tree; + u64 start = (u64)page->index << PAGE_CACHE_SHIFT; + u64 delalloc_start; + u64 page_end = start + PAGE_CACHE_SIZE - 1; + u64 end; + u64 cur = start; + u64 extent_offset; + u64 last_byte = i_size_read(inode); + u64 block_start; + u64 iosize; + sector_t sector; + struct extent_state *cached_state = NULL; + struct extent_map *em; + struct block_device *bdev; + int ret; + int nr = 0; + size_t pg_offset = 0; + size_t blocksize; + loff_t i_size = i_size_read(inode); + unsigned long end_index = i_size >> PAGE_CACHE_SHIFT; + u64 nr_delalloc; + u64 delalloc_end; + int page_started; + int compressed; + int write_flags; + unsigned long nr_written = 0; + bool fill_delalloc = true; + + if (wbc->sync_mode == WB_SYNC_ALL) + write_flags = WRITE_SYNC; + else + write_flags = WRITE; + + trace___extent_writepage(page, inode, wbc); + + WARN_ON(!PageLocked(page)); + + ClearPageError(page); + + pg_offset = i_size & (PAGE_CACHE_SIZE - 1); + if (page->index > end_index || + (page->index == end_index && !pg_offset)) { + page->mapping->a_ops->invalidatepage(page, 0); + unlock_page(page); + return 0; + } + + if (page->index == end_index) { + char *userpage; + + userpage = kmap_atomic(page); + memset(userpage + pg_offset, 0, + PAGE_CACHE_SIZE - pg_offset); + kunmap_atomic(userpage); + flush_dcache_page(page); + } + pg_offset = 0; + + set_page_extent_mapped(page); + + if (!tree->ops || !tree->ops->fill_delalloc) + fill_delalloc = false; + + delalloc_start = start; + delalloc_end = 0; + page_started = 0; + if (!epd->extent_locked && fill_delalloc) { + u64 delalloc_to_write = 0; + /* + * make sure the wbc mapping index is at least updated + * to this page. + */ + update_nr_written(page, wbc, 0); + + while (delalloc_end < page_end) { + nr_delalloc = find_lock_delalloc_range(inode, tree, + page, + &delalloc_start, + &delalloc_end, + 128 * 1024 * 1024); + if (nr_delalloc == 0) { + delalloc_start = delalloc_end + 1; + continue; + } + ret = tree->ops->fill_delalloc(inode, page, + delalloc_start, + delalloc_end, + &page_started, + &nr_written); + /* File system has been set read-only */ + if (ret) { + SetPageError(page); + goto done; + } + /* + * delalloc_end is already one less than the total + * length, so we don't subtract one from + * PAGE_CACHE_SIZE + */ + delalloc_to_write += (delalloc_end - delalloc_start + + PAGE_CACHE_SIZE) >> + PAGE_CACHE_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) { + ret = 0; + /* + * 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; + goto done_unlocked; + } + } + if (tree->ops && tree->ops->writepage_start_hook) { + ret = tree->ops->writepage_start_hook(page, start, + page_end); + if (ret) { + /* Fixup worker will requeue */ + if (ret == -EBUSY) + wbc->pages_skipped++; + else + redirty_page_for_writepage(wbc, page); + update_nr_written(page, wbc, nr_written); + unlock_page(page); + ret = 0; + goto done_unlocked; + } + } + + /* + * we don't want to touch the inode after unlocking the page, + * so we update the mapping writeback index now + */ + update_nr_written(page, wbc, nr_written + 1); + + end = page_end; + if (last_byte <= start) { + if (tree->ops && tree->ops->writepage_end_io_hook) + tree->ops->writepage_end_io_hook(page, start, + page_end, NULL, 1); + goto done; + } + + blocksize = inode->i_sb->s_blocksize; + + while (cur <= end) { + if (cur >= last_byte) { + if (tree->ops && tree->ops->writepage_end_io_hook) + tree->ops->writepage_end_io_hook(page, cur, + page_end, NULL, 1); + break; + } + em = epd->get_extent(inode, page, pg_offset, cur, + end - cur + 1, 1); + if (IS_ERR_OR_NULL(em)) { + SetPageError(page); + break; + } + + extent_offset = cur - em->start; + BUG_ON(extent_map_end(em) <= cur); + BUG_ON(end < cur); + iosize = min(extent_map_end(em) - cur, end - cur + 1); + iosize = (iosize + blocksize - 1) & ~((u64)blocksize - 1); + sector = (em->block_start + extent_offset) >> 9; + bdev = em->bdev; + 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) { + /* + * end_io notification does not happen here for + * compressed extents + */ + if (!compressed && tree->ops && + tree->ops->writepage_end_io_hook) + tree->ops->writepage_end_io_hook(page, cur, + cur + iosize - 1, + NULL, 1); + else if (compressed) { + /* we don't want to end_page_writeback on + * a compressed extent. this happens + * elsewhere + */ + nr++; + } + + cur += iosize; + pg_offset += iosize; + continue; + } + /* leave this out until we have a page_mkwrite call */ + if (0 && !test_range_bit(tree, cur, cur + iosize - 1, + EXTENT_DIRTY, 0, NULL)) { + cur = cur + iosize; + pg_offset += iosize; + continue; + } + + if (tree->ops && tree->ops->writepage_io_hook) { + ret = tree->ops->writepage_io_hook(page, cur, + cur + iosize - 1); + } else { + ret = 0; + } + if (ret) { + SetPageError(page); + } else { + unsigned long max_nr = end_index + 1; + + set_range_writeback(tree, cur, cur + iosize - 1); + if (!PageWriteback(page)) { + printk(KERN_ERR "btrfs warning page %lu not " + "writeback, cur %llu end %llu\n", + page->index, (unsigned long long)cur, + (unsigned long long)end); + } + + ret = submit_extent_page(write_flags, tree, page, + sector, iosize, pg_offset, + bdev, &epd->bio, max_nr, + end_bio_extent_writepage, + 0, 0, 0); + if (ret) + SetPageError(page); + } + cur = cur + iosize; + pg_offset += iosize; + nr++; + } +done: + if (nr == 0) { + /* make sure the mapping tag for page dirty gets cleared */ + set_page_writeback(page); + end_page_writeback(page); + } + unlock_page(page); + +done_unlocked: + + /* drop our reference on any cached states */ + free_extent_state(cached_state); + return 0; +} + +static int eb_wait(void *word) +{ + io_schedule(); + return 0; +} + +static void wait_on_extent_buffer_writeback(struct extent_buffer *eb) +{ + wait_on_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK, eb_wait, + TASK_UNINTERRUPTIBLE); +} + +static int lock_extent_buffer_for_io(struct extent_buffer *eb, + struct btrfs_fs_info *fs_info, + struct extent_page_data *epd) +{ + unsigned long i, num_pages; + int flush = 0; + int ret = 0; + + if (!btrfs_try_tree_write_lock(eb)) { + flush = 1; + flush_write_bio(epd); + btrfs_tree_lock(eb); + } + + if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) { + btrfs_tree_unlock(eb); + if (!epd->sync_io) + return 0; + if (!flush) { + flush_write_bio(epd); + 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); + } + } + + if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) { + set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags); + btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN); + spin_lock(&fs_info->delalloc_lock); + if (fs_info->dirty_metadata_bytes >= eb->len) + fs_info->dirty_metadata_bytes -= eb->len; + else + WARN_ON(1); + spin_unlock(&fs_info->delalloc_lock); + ret = 1; + } + + btrfs_tree_unlock(eb); + + if (!ret) + return ret; + + num_pages = num_extent_pages(eb->start, eb->len); + for (i = 0; i < num_pages; i++) { + struct page *p = extent_buffer_page(eb, i); + + if (!trylock_page(p)) { + if (!flush) { + flush_write_bio(epd); + flush = 1; + } + lock_page(p); + } + } + + return ret; +} + +static void end_extent_buffer_writeback(struct extent_buffer *eb) +{ + clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags); + smp_mb__after_clear_bit(); + wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK); +} + +static void end_bio_extent_buffer_writepage(struct bio *bio, int err) +{ + int uptodate = err == 0; + struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; + struct extent_buffer *eb; + int done; + + do { + struct page *page = bvec->bv_page; + + bvec--; + eb = (struct extent_buffer *)page->private; + BUG_ON(!eb); + done = atomic_dec_and_test(&eb->io_pages); + + if (!uptodate || test_bit(EXTENT_BUFFER_IOERR, &eb->bflags)) { + set_bit(EXTENT_BUFFER_IOERR, &eb->bflags); + ClearPageUptodate(page); + SetPageError(page); + } + + end_page_writeback(page); + + if (!done) + continue; + + end_extent_buffer_writeback(eb); + } while (bvec >= bio->bi_io_vec); + + bio_put(bio); + +} + +static int write_one_eb(struct extent_buffer *eb, + struct btrfs_fs_info *fs_info, + struct writeback_control *wbc, + struct extent_page_data *epd) +{ + struct block_device *bdev = fs_info->fs_devices->latest_bdev; + u64 offset = eb->start; + unsigned long i, num_pages; + int rw = (epd->sync_io ? WRITE_SYNC : WRITE); + int ret; + + clear_bit(EXTENT_BUFFER_IOERR, &eb->bflags); + num_pages = num_extent_pages(eb->start, eb->len); + atomic_set(&eb->io_pages, num_pages); + for (i = 0; i < num_pages; i++) { + struct page *p = extent_buffer_page(eb, i); + + clear_page_dirty_for_io(p); + set_page_writeback(p); + ret = submit_extent_page(rw, eb->tree, p, offset >> 9, + PAGE_CACHE_SIZE, 0, bdev, &epd->bio, + -1, end_bio_extent_buffer_writepage, + 0, 0, 0); + if (ret) { + set_bit(EXTENT_BUFFER_IOERR, &eb->bflags); + SetPageError(p); + if (atomic_sub_and_test(num_pages - i, &eb->io_pages)) + end_extent_buffer_writeback(eb); + ret = -EIO; + break; + } + offset += PAGE_CACHE_SIZE; + update_nr_written(p, wbc, 1); + unlock_page(p); + } + + if (unlikely(ret)) { + for (; i < num_pages; i++) { + struct page *p = extent_buffer_page(eb, i); + unlock_page(p); + } + } + + return ret; +} + +int btree_write_cache_pages(struct address_space *mapping, + struct writeback_control *wbc) +{ + struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree; + struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info; + struct extent_buffer *eb, *prev_eb = NULL; + struct extent_page_data epd = { + .bio = NULL, + .tree = tree, + .extent_locked = 0, + .sync_io = wbc->sync_mode == WB_SYNC_ALL, + }; + int ret = 0; + int done = 0; + int nr_to_write_done = 0; + struct pagevec pvec; + int nr_pages; + pgoff_t index; + pgoff_t end; /* Inclusive */ + int scanned = 0; + int tag; + + pagevec_init(&pvec, 0); + if (wbc->range_cyclic) { + index = mapping->writeback_index; /* Start from prev offset */ + end = -1; + } else { + index = wbc->range_start >> PAGE_CACHE_SHIFT; + end = wbc->range_end >> PAGE_CACHE_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_tag(&pvec, mapping, &index, tag, + min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) { + unsigned i; + + scanned = 1; + for (i = 0; i < nr_pages; i++) { + struct page *page = pvec.pages[i]; + + if (!PagePrivate(page)) + continue; + + if (!wbc->range_cyclic && page->index > end) { + done = 1; + break; + } + + eb = (struct extent_buffer *)page->private; + if (!eb) { + WARN_ON(1); + continue; + } + + if (eb == prev_eb) + continue; + + if (!atomic_inc_not_zero(&eb->refs)) { + WARN_ON(1); + continue; + } + + prev_eb = eb; + ret = lock_extent_buffer_for_io(eb, fs_info, &epd); + if (!ret) { + free_extent_buffer(eb); + continue; + } + + ret = write_one_eb(eb, fs_info, wbc, &epd); + if (ret) { + done = 1; + free_extent_buffer(eb); + break; + } + free_extent_buffer(eb); + + /* + * the filesystem may choose to bump up nr_to_write. + * We have to make sure to honor the new nr_to_write + * at any time + */ + nr_to_write_done = wbc->nr_to_write <= 0; + } + pagevec_release(&pvec); + cond_resched(); + } + if (!scanned && !done) { + /* + * We hit the last page and there is more work to be done: wrap + * back to the start of the file + */ + scanned = 1; + index = 0; + goto retry; + } + flush_write_bio(&epd); + return ret; +} + +/** + * write_cache_pages - walk the list of dirty pages of the given address space and write all of them. + * @mapping: address space structure to write + * @wbc: subtract the number of written pages from *@wbc->nr_to_write + * @writepage: function called for each page + * @data: data passed to 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 extent_io_tree *tree, + struct address_space *mapping, + struct writeback_control *wbc, + writepage_t writepage, void *data, + void (*flush_fn)(void *)) +{ + 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; + int tag; + + pagevec_init(&pvec, 0); + if (wbc->range_cyclic) { + index = mapping->writeback_index; /* Start from prev offset */ + end = -1; + } else { + index = wbc->range_start >> PAGE_CACHE_SHIFT; + end = wbc->range_end >> PAGE_CACHE_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_tag(&pvec, mapping, &index, tag, + min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) { + unsigned i; + + scanned = 1; + for (i = 0; i < nr_pages; i++) { + struct page *page = pvec.pages[i]; + + /* + * At this point we hold neither mapping->tree_lock nor + * lock on the page itself: the page may be truncated or + * invalidated (changing page->mapping to NULL), or even + * swizzled back from swapper_space to tmpfs file + * mapping + */ + if (tree->ops && + tree->ops->write_cache_pages_lock_hook) { + tree->ops->write_cache_pages_lock_hook(page, + data, flush_fn); + } else { + if (!trylock_page(page)) { + flush_fn(data); + lock_page(page); + } + } + + if (unlikely(page->mapping != mapping)) { + unlock_page(page); + continue; + } + + if (!wbc->range_cyclic && page->index > end) { + done = 1; + unlock_page(page); + continue; + } + + if (wbc->sync_mode != WB_SYNC_NONE) { + if (PageWriteback(page)) + flush_fn(data); + wait_on_page_writeback(page); + } + + if (PageWriteback(page) || + !clear_page_dirty_for_io(page)) { + unlock_page(page); + continue; + } + + ret = (*writepage)(page, wbc, data); + + if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) { + unlock_page(page); + ret = 0; + } + if (ret) + done = 1; + + /* + * the filesystem may choose to bump up nr_to_write. + * We have to make sure to honor the new nr_to_write + * at any time + */ + nr_to_write_done = wbc->nr_to_write <= 0; + } + pagevec_release(&pvec); + cond_resched(); + } + if (!scanned && !done) { + /* + * We hit the last page and there is more work to be done: wrap + * back to the start of the file + */ + scanned = 1; + index = 0; + goto retry; + } + return ret; +} + +static void flush_epd_write_bio(struct extent_page_data *epd) +{ + if (epd->bio) { + int rw = WRITE; + int ret; + + if (epd->sync_io) + rw = WRITE_SYNC; + + ret = submit_one_bio(rw, epd->bio, 0, 0); + BUG_ON(ret < 0); /* -ENOMEM */ + epd->bio = NULL; + } +} + +static noinline void flush_write_bio(void *data) +{ + struct extent_page_data *epd = data; + flush_epd_write_bio(epd); +} + +int extent_write_full_page(struct extent_io_tree *tree, struct page *page, + get_extent_t *get_extent, + struct writeback_control *wbc) +{ + int ret; + struct extent_page_data epd = { + .bio = NULL, + .tree = tree, + .get_extent = get_extent, + .extent_locked = 0, + .sync_io = wbc->sync_mode == WB_SYNC_ALL, + }; + + ret = __extent_writepage(page, wbc, &epd); + + flush_epd_write_bio(&epd); + return ret; +} + +int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode, + u64 start, u64 end, get_extent_t *get_extent, + int mode) +{ + int ret = 0; + struct address_space *mapping = inode->i_mapping; + struct page *page; + unsigned long nr_pages = (end - start + PAGE_CACHE_SIZE) >> + PAGE_CACHE_SHIFT; + + struct extent_page_data epd = { + .bio = NULL, + .tree = tree, + .get_extent = get_extent, + .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, + }; + + while (start <= end) { + page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT); + if (clear_page_dirty_for_io(page)) + ret = __extent_writepage(page, &wbc_writepages, &epd); + else { + if (tree->ops && tree->ops->writepage_end_io_hook) + tree->ops->writepage_end_io_hook(page, start, + start + PAGE_CACHE_SIZE - 1, + NULL, 1); + unlock_page(page); + } + page_cache_release(page); + start += PAGE_CACHE_SIZE; + } + + flush_epd_write_bio(&epd); + return ret; +} + +int extent_writepages(struct extent_io_tree *tree, + struct address_space *mapping, + get_extent_t *get_extent, + struct writeback_control *wbc) +{ + int ret = 0; + struct extent_page_data epd = { + .bio = NULL, + .tree = tree, + .get_extent = get_extent, + .extent_locked = 0, + .sync_io = wbc->sync_mode == WB_SYNC_ALL, + }; + + ret = extent_write_cache_pages(tree, mapping, wbc, + __extent_writepage, &epd, + flush_write_bio); + flush_epd_write_bio(&epd); + return ret; +} + +int extent_readpages(struct extent_io_tree *tree, + struct address_space *mapping, + struct list_head *pages, unsigned nr_pages, + get_extent_t get_extent) +{ + struct bio *bio = NULL; + unsigned page_idx; + unsigned long bio_flags = 0; + + for (page_idx = 0; page_idx < nr_pages; page_idx++) { + struct page *page = list_entry(pages->prev, struct page, lru); + + prefetchw(&page->flags); + list_del(&page->lru); + if (!add_to_page_cache_lru(page, mapping, + page->index, GFP_NOFS)) { + __extent_read_full_page(tree, page, get_extent, + &bio, 0, &bio_flags); + } + page_cache_release(page); + } + BUG_ON(!list_empty(pages)); + if (bio) + return submit_one_bio(READ, bio, 0, bio_flags); + return 0; +} + +/* + * basic invalidatepage code, this waits on any locked or writeback + * ranges corresponding to the page, and then deletes any extent state + * records from the tree + */ +int extent_invalidatepage(struct extent_io_tree *tree, + struct page *page, unsigned long offset) +{ + struct extent_state *cached_state = NULL; + u64 start = ((u64)page->index << PAGE_CACHE_SHIFT); + u64 end = start + PAGE_CACHE_SIZE - 1; + size_t blocksize = page->mapping->host->i_sb->s_blocksize; + + start += (offset + blocksize - 1) & ~(blocksize - 1); + if (start > end) + return 0; + + lock_extent_bits(tree, start, end, 0, &cached_state); + wait_on_page_writeback(page); + clear_extent_bit(tree, start, end, + EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC | + EXTENT_DO_ACCOUNTING, + 1, 1, &cached_state, GFP_NOFS); + 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. + */ +int try_release_extent_state(struct extent_map_tree *map, + struct extent_io_tree *tree, struct page *page, + gfp_t mask) +{ + u64 start = (u64)page->index << PAGE_CACHE_SHIFT; + u64 end = start + PAGE_CACHE_SIZE - 1; + int ret = 1; + + if (test_range_bit(tree, start, end, + EXTENT_IOBITS, 0, NULL)) + ret = 0; + else { + if ((mask & GFP_NOFS) == GFP_NOFS) + mask = GFP_NOFS; + /* + * 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); + + /* 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 extent_map_tree *map, + struct extent_io_tree *tree, struct page *page, + gfp_t mask) +{ + struct extent_map *em; + u64 start = (u64)page->index << PAGE_CACHE_SHIFT; + u64 end = start + PAGE_CACHE_SIZE - 1; + + if ((mask & __GFP_WAIT) && + page->mapping->host->i_size > 16 * 1024 * 1024) { + u64 len; + while (start <= end) { + len = end - start + 1; + write_lock(&map->lock); + em = lookup_extent_mapping(map, start, len); + if (!em) { + write_unlock(&map->lock); + break; + } + if (test_bit(EXTENT_FLAG_PINNED, &em->flags) || + em->start != start) { + write_unlock(&map->lock); + free_extent_map(em); + break; + } + if (!test_range_bit(tree, em->start, + extent_map_end(em) - 1, + EXTENT_LOCKED | EXTENT_WRITEBACK, + 0, NULL)) { + remove_extent_mapping(map, em); + /* once for the rb tree */ + free_extent_map(em); + } + start = extent_map_end(em); + write_unlock(&map->lock); + + /* once for us */ + free_extent_map(em); + } + } + return try_release_extent_state(map, tree, page, mask); +} + +/* + * helper function for fiemap, which doesn't want to see any holes. + * This maps until we find something past 'last' + */ +static struct extent_map *get_extent_skip_holes(struct inode *inode, + u64 offset, + u64 last, + get_extent_t *get_extent) +{ + u64 sectorsize = BTRFS_I(inode)->root->sectorsize; + struct extent_map *em; + u64 len; + + if (offset >= last) + return NULL; + + while(1) { + len = last - offset; + if (len == 0) + break; + len = (len + sectorsize - 1) & ~(sectorsize - 1); + em = get_extent(inode, NULL, 0, offset, len, 0); + if (IS_ERR_OR_NULL(em)) + return em; + + /* if this isn't a hole return it */ + if (!test_bit(EXTENT_FLAG_VACANCY, &em->flags) && + 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; +} + +int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, + __u64 start, __u64 len, get_extent_t *get_extent) +{ + int ret = 0; + u64 off = start; + u64 max = start + len; + u32 flags = 0; + u32 found_type; + u64 last; + u64 last_for_get_extent = 0; + u64 disko = 0; + u64 isize = i_size_read(inode); + struct btrfs_key found_key; + struct extent_map *em = NULL; + struct extent_state *cached_state = NULL; + struct btrfs_path *path; + struct btrfs_file_extent_item *item; + int end = 0; + u64 em_start = 0; + u64 em_len = 0; + u64 em_end = 0; + unsigned long emflags; + + if (len == 0) + return -EINVAL; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + path->leave_spinning = 1; + + start = ALIGN(start, BTRFS_I(inode)->root->sectorsize); + len = ALIGN(len, BTRFS_I(inode)->root->sectorsize); + + /* + * 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, BTRFS_I(inode)->root, + path, btrfs_ino(inode), -1, 0); + if (ret < 0) { + btrfs_free_path(path); + return ret; + } + WARN_ON(!ret); + path->slots[0]--; + item = btrfs_item_ptr(path->nodes[0], path->slots[0], + struct btrfs_file_extent_item); + btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]); + found_type = btrfs_key_type(&found_key); + + /* 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_free_path(path); + + /* + * we might have some extents allocated but more delalloc past those + * extents. so, we trust isize unless the start of the last extent is + * beyond isize + */ + if (last < isize) { + last = (u64)-1; + last_for_get_extent = isize; + } + + lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len, 0, + &cached_state); + + em = get_extent_skip_holes(inode, start, last_for_get_extent, + get_extent); + if (!em) + goto out; + if (IS_ERR(em)) { + ret = PTR_ERR(em); + goto out; + } + + while (!end) { + u64 offset_in_extent; + + /* 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 + */ + offset_in_extent = em_start - em->start; + em_end = extent_map_end(em); + em_len = em_end - em_start; + emflags = em->flags; + disko = 0; + flags = 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 { + disko = em->block_start + offset_in_extent; + } + if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) + flags |= FIEMAP_EXTENT_ENCODED; + + 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, + get_extent); + if (IS_ERR(em)) { + ret = PTR_ERR(em); + goto out; + } + if (!em) { + flags |= FIEMAP_EXTENT_LAST; + end = 1; + } + ret = fiemap_fill_next_extent(fieinfo, em_start, disko, + em_len, flags); + if (ret) + goto out_free; + } +out_free: + free_extent_map(em); +out: + unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len, + &cached_state, GFP_NOFS); + return ret; +} + +inline struct page *extent_buffer_page(struct extent_buffer *eb, + unsigned long i) +{ + return eb->pages[i]; +} + +inline unsigned long num_extent_pages(u64 start, u64 len) +{ + return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) - + (start >> PAGE_CACHE_SHIFT); +} + +static void __free_extent_buffer(struct extent_buffer *eb) +{ +#if LEAK_DEBUG + unsigned long flags; + spin_lock_irqsave(&leak_lock, flags); + list_del(&eb->leak_list); + spin_unlock_irqrestore(&leak_lock, flags); +#endif + if (eb->pages && eb->pages != eb->inline_pages) + kfree(eb->pages); + kmem_cache_free(extent_buffer_cache, eb); +} + +static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree, + u64 start, + unsigned long len, + gfp_t mask) +{ + struct extent_buffer *eb = NULL; +#if LEAK_DEBUG + unsigned long flags; +#endif + + eb = kmem_cache_zalloc(extent_buffer_cache, mask); + if (eb == NULL) + return NULL; + eb->start = start; + eb->len = len; + eb->tree = tree; + rwlock_init(&eb->lock); + atomic_set(&eb->write_locks, 0); + atomic_set(&eb->read_locks, 0); + atomic_set(&eb->blocking_readers, 0); + atomic_set(&eb->blocking_writers, 0); + atomic_set(&eb->spinning_readers, 0); + atomic_set(&eb->spinning_writers, 0); + eb->lock_nested = 0; + init_waitqueue_head(&eb->write_lock_wq); + init_waitqueue_head(&eb->read_lock_wq); + +#if LEAK_DEBUG + spin_lock_irqsave(&leak_lock, flags); + list_add(&eb->leak_list, &buffers); + spin_unlock_irqrestore(&leak_lock, flags); +#endif + spin_lock_init(&eb->refs_lock); + atomic_set(&eb->refs, 1); + atomic_set(&eb->io_pages, 0); + + if (len > MAX_INLINE_EXTENT_BUFFER_SIZE) { + struct page **pages; + int num_pages = (len + PAGE_CACHE_SIZE - 1) >> + PAGE_CACHE_SHIFT; + pages = kzalloc(num_pages, mask); + if (!pages) { + __free_extent_buffer(eb); + return NULL; + } + eb->pages = pages; + } else { + eb->pages = eb->inline_pages; + } + + return eb; +} + +static int extent_buffer_under_io(struct extent_buffer *eb) +{ + return (atomic_read(&eb->io_pages) || + test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) || + test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)); +} + +/* + * Helper for releasing extent buffer page. + */ +static void btrfs_release_extent_buffer_page(struct extent_buffer *eb, + unsigned long start_idx) +{ + unsigned long index; + struct page *page; + + BUG_ON(extent_buffer_under_io(eb)); + + index = num_extent_pages(eb->start, eb->len); + if (start_idx >= index) + return; + + do { + index--; + page = extent_buffer_page(eb, index); + if (page) { + spin_lock(&page->mapping->private_lock); + /* + * We do this since we'll remove the pages after we've + * removed the eb from the radix tree, so we could race + * and have this page now attached to the new eb. So + * only clear page_private if it's still connected to + * this eb. + */ + if (PagePrivate(page) && + page->private == (unsigned long)eb) { + BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)); + BUG_ON(PageDirty(page)); + BUG_ON(PageWriteback(page)); + /* + * We need to make sure we haven't be attached + * to a new eb. + */ + ClearPagePrivate(page); + set_page_private(page, 0); + /* One for the page private */ + page_cache_release(page); + } + spin_unlock(&page->mapping->private_lock); + + /* One for when we alloced the page */ + page_cache_release(page); + } + } while (index != start_idx); +} + +/* + * Helper for releasing the extent buffer. + */ +static inline void btrfs_release_extent_buffer(struct extent_buffer *eb) +{ + btrfs_release_extent_buffer_page(eb, 0); + __free_extent_buffer(eb); +} + +static void check_buffer_tree_ref(struct extent_buffer *eb) +{ + /* the ref bit is tricky. We have to make sure it is set + * if we have the buffer dirty. Otherwise the + * code to free a buffer can end up dropping a dirty + * page + * + * Once the ref bit is set, it won't go away while the + * buffer is dirty or in writeback, and it also won't + * go away while we have the reference count on the + * eb bumped. + * + * We can't just set the ref bit without bumping the + * ref on the eb because free_extent_buffer might + * see the ref bit and try to clear it. If this happens + * free_extent_buffer might end up dropping our original + * ref by mistake and freeing the page before we are able + * to add one more ref. + * + * So bump the ref count first, then set the bit. If someone + * beat us to it, drop the ref we added. + */ + if (!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) { + atomic_inc(&eb->refs); + if (test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) + atomic_dec(&eb->refs); + } +} + +static void mark_extent_buffer_accessed(struct extent_buffer *eb) +{ + unsigned long num_pages, i; + + check_buffer_tree_ref(eb); + + num_pages = num_extent_pages(eb->start, eb->len); + for (i = 0; i < num_pages; i++) { + struct page *p = extent_buffer_page(eb, i); + mark_page_accessed(p); + } +} + +struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree, + u64 start, unsigned long len) +{ + unsigned long num_pages = num_extent_pages(start, len); + unsigned long i; + unsigned long index = start >> PAGE_CACHE_SHIFT; + struct extent_buffer *eb; + struct extent_buffer *exists = NULL; + struct page *p; + struct address_space *mapping = tree->mapping; + int uptodate = 1; + int ret; + + rcu_read_lock(); + eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT); + if (eb && atomic_inc_not_zero(&eb->refs)) { + rcu_read_unlock(); + mark_extent_buffer_accessed(eb); + return eb; + } + rcu_read_unlock(); + + eb = __alloc_extent_buffer(tree, start, len, GFP_NOFS); + if (!eb) + return NULL; + + for (i = 0; i < num_pages; i++, index++) { + p = find_or_create_page(mapping, index, GFP_NOFS); + if (!p) { + WARN_ON(1); + 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); + page_cache_release(p); + mark_extent_buffer_accessed(exists); + goto free_eb; + } + + /* + * Do this so attach doesn't complain and we need to + * drop the ref the old guy had. + */ + ClearPagePrivate(p); + WARN_ON(PageDirty(p)); + page_cache_release(p); + } + attach_extent_buffer_page(eb, p); + spin_unlock(&mapping->private_lock); + WARN_ON(PageDirty(p)); + mark_page_accessed(p); + eb->pages[i] = p; + if (!PageUptodate(p)) + uptodate = 0; + + /* + * see below about how we avoid a nasty race with release page + * and why we unlock later + */ + } + if (uptodate) + set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags); +again: + ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM); + if (ret) + goto free_eb; + + spin_lock(&tree->buffer_lock); + ret = radix_tree_insert(&tree->buffer, start >> PAGE_CACHE_SHIFT, eb); + if (ret == -EEXIST) { + exists = radix_tree_lookup(&tree->buffer, + start >> PAGE_CACHE_SHIFT); + if (!atomic_inc_not_zero(&exists->refs)) { + spin_unlock(&tree->buffer_lock); + radix_tree_preload_end(); + exists = NULL; + goto again; + } + spin_unlock(&tree->buffer_lock); + radix_tree_preload_end(); + mark_extent_buffer_accessed(exists); + goto free_eb; + } + /* add one reference for the tree */ + spin_lock(&eb->refs_lock); + check_buffer_tree_ref(eb); + spin_unlock(&eb->refs_lock); + spin_unlock(&tree->buffer_lock); + radix_tree_preload_end(); + + /* + * there is a race where release page may have + * tried to find this extent buffer in the radix + * but failed. It will tell the VM it is safe to + * reclaim the, and it will clear the page private bit. + * We must make sure to set the page private bit properly + * after the extent buffer is in the radix tree so + * it doesn't get lost + */ + SetPageChecked(eb->pages[0]); + for (i = 1; i < num_pages; i++) { + p = extent_buffer_page(eb, i); + ClearPageChecked(p); + unlock_page(p); + } + unlock_page(eb->pages[0]); + return eb; + +free_eb: + for (i = 0; i < num_pages; i++) { + if (eb->pages[i]) + unlock_page(eb->pages[i]); + } + + WARN_ON(!atomic_dec_and_test(&eb->refs)); + btrfs_release_extent_buffer(eb); + return exists; +} + +struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree, + u64 start, unsigned long len) +{ + struct extent_buffer *eb; + + rcu_read_lock(); + eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT); + if (eb && atomic_inc_not_zero(&eb->refs)) { + rcu_read_unlock(); + mark_extent_buffer_accessed(eb); + return eb; + } + rcu_read_unlock(); + + return NULL; +} + +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); +} + +/* Expects to have eb->eb_lock already held */ +static void release_extent_buffer(struct extent_buffer *eb, gfp_t mask) +{ + WARN_ON(atomic_read(&eb->refs) == 0); + if (atomic_dec_and_test(&eb->refs)) { + struct extent_io_tree *tree = eb->tree; + + spin_unlock(&eb->refs_lock); + + spin_lock(&tree->buffer_lock); + radix_tree_delete(&tree->buffer, + eb->start >> PAGE_CACHE_SHIFT); + spin_unlock(&tree->buffer_lock); + + /* Should be safe to release our pages at this point */ + btrfs_release_extent_buffer_page(eb, 0); + + call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu); + return; + } + spin_unlock(&eb->refs_lock); +} + +void free_extent_buffer(struct extent_buffer *eb) +{ + if (!eb) + 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, GFP_ATOMIC); +} + +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, GFP_NOFS); +} + +void clear_extent_buffer_dirty(struct extent_buffer *eb) +{ + unsigned long i; + unsigned long num_pages; + struct page *page; + + num_pages = num_extent_pages(eb->start, eb->len); + + for (i = 0; i < num_pages; i++) { + page = extent_buffer_page(eb, i); + if (!PageDirty(page)) + continue; + + lock_page(page); + WARN_ON(!PagePrivate(page)); + + clear_page_dirty_for_io(page); + spin_lock_irq(&page->mapping->tree_lock); + if (!PageDirty(page)) { + radix_tree_tag_clear(&page->mapping->page_tree, + page_index(page), + PAGECACHE_TAG_DIRTY); + } + spin_unlock_irq(&page->mapping->tree_lock); + ClearPageError(page); + unlock_page(page); + } + WARN_ON(atomic_read(&eb->refs) == 0); +} + +int set_extent_buffer_dirty(struct extent_buffer *eb) +{ + unsigned long i; + unsigned long num_pages; + int was_dirty = 0; + + check_buffer_tree_ref(eb); + + was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags); + + num_pages = num_extent_pages(eb->start, eb->len); + WARN_ON(atomic_read(&eb->refs) == 0); + WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)); + + for (i = 0; i < num_pages; i++) + set_page_dirty(extent_buffer_page(eb, i)); + return was_dirty; +} + +static int range_straddles_pages(u64 start, u64 len) +{ + if (len < PAGE_CACHE_SIZE) + return 1; + if (start & (PAGE_CACHE_SIZE - 1)) + return 1; + if ((start + len) & (PAGE_CACHE_SIZE - 1)) + return 1; + return 0; +} + +int clear_extent_buffer_uptodate(struct extent_buffer *eb) +{ + unsigned long i; + struct page *page; + unsigned long num_pages; + + clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags); + num_pages = num_extent_pages(eb->start, eb->len); + for (i = 0; i < num_pages; i++) { + page = extent_buffer_page(eb, i); + if (page) + ClearPageUptodate(page); + } + return 0; +} + +int set_extent_buffer_uptodate(struct extent_buffer *eb) +{ + unsigned long i; + struct page *page; + unsigned long num_pages; + + set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags); + num_pages = num_extent_pages(eb->start, eb->len); + for (i = 0; i < num_pages; i++) { + page = extent_buffer_page(eb, i); + SetPageUptodate(page); + } + return 0; +} + +int extent_range_uptodate(struct extent_io_tree *tree, + u64 start, u64 end) +{ + struct page *page; + int ret; + int pg_uptodate = 1; + int uptodate; + unsigned long index; + + if (range_straddles_pages(start, end - start + 1)) { + ret = test_range_bit(tree, start, end, + EXTENT_UPTODATE, 1, NULL); + if (ret) + return 1; + } + while (start <= end) { + index = start >> PAGE_CACHE_SHIFT; + page = find_get_page(tree->mapping, index); + if (!page) + return 1; + uptodate = PageUptodate(page); + page_cache_release(page); + if (!uptodate) { + pg_uptodate = 0; + break; + } + start += PAGE_CACHE_SIZE; + } + return pg_uptodate; +} + +int extent_buffer_uptodate(struct extent_buffer *eb) +{ + return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags); +} + +int read_extent_buffer_pages(struct extent_io_tree *tree, + struct extent_buffer *eb, u64 start, int wait, + get_extent_t *get_extent, int mirror_num) +{ + unsigned long i; + unsigned long start_i; + struct page *page; + int err; + int ret = 0; + int locked_pages = 0; + int all_uptodate = 1; + unsigned long 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; + + if (start) { + WARN_ON(start < eb->start); + start_i = (start >> PAGE_CACHE_SHIFT) - + (eb->start >> PAGE_CACHE_SHIFT); + } else { + start_i = 0; + } + + num_pages = num_extent_pages(eb->start, eb->len); + for (i = start_i; i < num_pages; i++) { + page = extent_buffer_page(eb, i); + if (wait == WAIT_NONE) { + if (!trylock_page(page)) + goto unlock_exit; + } else { + lock_page(page); + } + locked_pages++; + if (!PageUptodate(page)) { + num_reads++; + all_uptodate = 0; + } + } + if (all_uptodate) { + if (start_i == 0) + set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags); + goto unlock_exit; + } + + clear_bit(EXTENT_BUFFER_IOERR, &eb->bflags); + eb->read_mirror = 0; + atomic_set(&eb->io_pages, num_reads); + for (i = start_i; i < num_pages; i++) { + page = extent_buffer_page(eb, i); + if (!PageUptodate(page)) { + ClearPageError(page); + err = __extent_read_full_page(tree, page, + get_extent, &bio, + mirror_num, &bio_flags); + if (err) + ret = err; + } else { + unlock_page(page); + } + } + + if (bio) { + err = submit_one_bio(READ, bio, mirror_num, bio_flags); + if (err) + return err; + } + + if (ret || wait != WAIT_COMPLETE) + return ret; + + for (i = start_i; i < num_pages; i++) { + page = extent_buffer_page(eb, i); + wait_on_page_locked(page); + if (!PageUptodate(page)) + ret = -EIO; + } + + return ret; + +unlock_exit: + i = start_i; + while (locked_pages > 0) { + page = extent_buffer_page(eb, i); + i++; + unlock_page(page); + locked_pages--; + } + return ret; +} + +void read_extent_buffer(struct extent_buffer *eb, void *dstv, + unsigned long start, + unsigned long len) +{ + size_t cur; + size_t offset; + struct page *page; + char *kaddr; + char *dst = (char *)dstv; + size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1); + unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT; + + WARN_ON(start > eb->len); + WARN_ON(start + len > eb->start + eb->len); + + offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1); + + while (len > 0) { + page = extent_buffer_page(eb, i); + + cur = min(len, (PAGE_CACHE_SIZE - offset)); + kaddr = page_address(page); + memcpy(dst, kaddr + offset, cur); + + dst += cur; + len -= cur; + offset = 0; + i++; + } +} + +int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start, + unsigned long min_len, char **map, + unsigned long *map_start, + unsigned long *map_len) +{ + size_t offset = start & (PAGE_CACHE_SIZE - 1); + char *kaddr; + struct page *p; + size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1); + unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT; + unsigned long end_i = (start_offset + start + min_len - 1) >> + PAGE_CACHE_SHIFT; + + if (i != end_i) + return -EINVAL; + + if (i == 0) { + offset = start_offset; + *map_start = 0; + } else { + offset = 0; + *map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset; + } + + if (start + min_len > eb->len) { + printk(KERN_ERR "btrfs bad mapping eb start %llu len %lu, " + "wanted %lu %lu\n", (unsigned long long)eb->start, + eb->len, start, min_len); + WARN_ON(1); + return -EINVAL; + } + + p = extent_buffer_page(eb, i); + kaddr = page_address(p); + *map = kaddr + offset; + *map_len = PAGE_CACHE_SIZE - offset; + return 0; +} + +int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv, + unsigned long start, + unsigned long len) +{ + size_t cur; + size_t offset; + struct page *page; + char *kaddr; + char *ptr = (char *)ptrv; + size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1); + unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT; + int ret = 0; + + WARN_ON(start > eb->len); + WARN_ON(start + len > eb->start + eb->len); + + offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1); + + while (len > 0) { + page = extent_buffer_page(eb, i); + + cur = min(len, (PAGE_CACHE_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(struct extent_buffer *eb, const void *srcv, + unsigned long start, unsigned long len) +{ + size_t cur; + size_t offset; + struct page *page; + char *kaddr; + char *src = (char *)srcv; + size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1); + unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT; + + WARN_ON(start > eb->len); + WARN_ON(start + len > eb->start + eb->len); + + offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1); + + while (len > 0) { + page = extent_buffer_page(eb, i); + WARN_ON(!PageUptodate(page)); + + cur = min(len, PAGE_CACHE_SIZE - offset); + kaddr = page_address(page); + memcpy(kaddr + offset, src, cur); + + src += cur; + len -= cur; + offset = 0; + i++; + } +} + +void memset_extent_buffer(struct extent_buffer *eb, char c, + unsigned long start, unsigned long len) +{ + size_t cur; + size_t offset; + struct page *page; + char *kaddr; + size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1); + unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT; + + WARN_ON(start > eb->len); + WARN_ON(start + len > eb->start + eb->len); + + offset = (start_offset + start) & ((unsigned long)PAGE_CACHE_SIZE - 1); + + while (len > 0) { + page = extent_buffer_page(eb, i); + WARN_ON(!PageUptodate(page)); + + cur = min(len, PAGE_CACHE_SIZE - offset); + kaddr = page_address(page); + memset(kaddr + offset, c, cur); + + len -= cur; + offset = 0; + i++; + } +} + +void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src, + unsigned long dst_offset, unsigned long src_offset, + unsigned long len) +{ + u64 dst_len = dst->len; + size_t cur; + size_t offset; + struct page *page; + char *kaddr; + size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1); + unsigned long i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT; + + WARN_ON(src->len != dst_len); + + offset = (start_offset + dst_offset) & + ((unsigned long)PAGE_CACHE_SIZE - 1); + + while (len > 0) { + page = extent_buffer_page(dst, i); + WARN_ON(!PageUptodate(page)); + + cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset)); + + kaddr = page_address(page); + read_extent_buffer(src, kaddr + offset, src_offset, cur); + + src_offset += cur; + len -= cur; + offset = 0; + i++; + } +} + +static void move_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); + if (dst_page == src_page) { + memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len); + } else { + char *src_kaddr = page_address(src_page); + char *p = dst_kaddr + dst_off + len; + char *s = src_kaddr + src_off + len; + + while (len--) + *--p = *--s; + } +} + +static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len) +{ + unsigned long distance = (src > dst) ? src - dst : dst - src; + return distance < len; +} + +static void copy_pages(struct page *dst_page, struct page *src_page, + unsigned long dst_off, unsigned long src_off, + unsigned long len) +{ + char *dst_kaddr = page_address(dst_page); + char *src_kaddr; + int must_memmove = 0; + + if (dst_page != src_page) { + src_kaddr = page_address(src_page); + } else { + src_kaddr = dst_kaddr; + if (areas_overlap(src_off, dst_off, len)) + must_memmove = 1; + } + + if (must_memmove) + memmove(dst_kaddr + dst_off, src_kaddr + src_off, len); + else + memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len); +} + +void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset, + unsigned long src_offset, unsigned long len) +{ + size_t cur; + size_t dst_off_in_page; + size_t src_off_in_page; + size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1); + unsigned long dst_i; + unsigned long src_i; + + if (src_offset + len > dst->len) { + printk(KERN_ERR "btrfs memmove bogus src_offset %lu move " + "len %lu dst len %lu\n", src_offset, len, dst->len); + BUG_ON(1); + } + if (dst_offset + len > dst->len) { + printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move " + "len %lu dst len %lu\n", dst_offset, len, dst->len); + BUG_ON(1); + } + + while (len > 0) { + dst_off_in_page = (start_offset + dst_offset) & + ((unsigned long)PAGE_CACHE_SIZE - 1); + src_off_in_page = (start_offset + src_offset) & + ((unsigned long)PAGE_CACHE_SIZE - 1); + + dst_i = (start_offset + dst_offset) >> PAGE_CACHE_SHIFT; + src_i = (start_offset + src_offset) >> PAGE_CACHE_SHIFT; + + cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - + src_off_in_page)); + cur = min_t(unsigned long, cur, + (unsigned long)(PAGE_CACHE_SIZE - dst_off_in_page)); + + copy_pages(extent_buffer_page(dst, dst_i), + extent_buffer_page(dst, src_i), + dst_off_in_page, src_off_in_page, cur); + + src_offset += cur; + dst_offset += cur; + len -= cur; + } +} + +void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset, + unsigned long src_offset, unsigned long len) +{ + size_t cur; + size_t dst_off_in_page; + size_t src_off_in_page; + unsigned long dst_end = dst_offset + len - 1; + unsigned long src_end = src_offset + len - 1; + size_t start_offset = dst->start & ((u64)PAGE_CACHE_SIZE - 1); + unsigned long dst_i; + unsigned long src_i; + + if (src_offset + len > dst->len) { + printk(KERN_ERR "btrfs memmove bogus src_offset %lu move " + "len %lu len %lu\n", src_offset, len, dst->len); + BUG_ON(1); + } + if (dst_offset + len > dst->len) { + printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move " + "len %lu len %lu\n", dst_offset, len, dst->len); + BUG_ON(1); + } + if (dst_offset < src_offset) { + memcpy_extent_buffer(dst, dst_offset, src_offset, len); + return; + } + while (len > 0) { + dst_i = (start_offset + dst_end) >> PAGE_CACHE_SHIFT; + src_i = (start_offset + src_end) >> PAGE_CACHE_SHIFT; + + dst_off_in_page = (start_offset + dst_end) & + ((unsigned long)PAGE_CACHE_SIZE - 1); + src_off_in_page = (start_offset + src_end) & + ((unsigned long)PAGE_CACHE_SIZE - 1); + + cur = min_t(unsigned long, len, src_off_in_page + 1); + cur = min(cur, dst_off_in_page + 1); + move_pages(extent_buffer_page(dst, dst_i), + extent_buffer_page(dst, 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, gfp_t mask) +{ + struct extent_buffer *eb; + + /* + * We need to make sure noboody 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 ((mask & GFP_NOFS) == GFP_NOFS) + mask = GFP_NOFS; + + /* + * 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; + } + release_extent_buffer(eb, mask); + + return 1; +} |