#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" #include "rcu-string.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; unsigned long bio_flags; /* 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("btrfs_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("btrfs_extent_buffer", 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); } /* * Make sure all delayed rcu free are flushed before we * destroy caches. */ rcu_barrier(); 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; } 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) WARN(1, KERN_ERR "btrfs end < start %llu %llu\n", (unsigned long long)end, (unsigned long long)start); 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) { state = clear_state_bit(tree, state, &bits, wake); goto next; } goto search_again; } /* * | ---- desired range ---- | * | state | * We need to split the extent, and clear the bit * on the first half */ if (state->start <= end && state->end > end) { prealloc = alloc_extent_state_atomic(prealloc); BUG_ON(!prealloc); err = split_state(tree, state, prealloc, end + 1); if (err) extent_io_tree_panic(tree, err); if (wake) wake_up(&state->wq); clear_state_bit(tree, prealloc, &bits, wake); 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) { 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; state = next_state(state); if (start < end && state && state->start == start && !need_resched()) goto hit_next; goto search_again; } /* * | ---- desired range ---- | * | state | * or * | ------------- state -------------- | * * We need to split the extent we found, and may flip bits on * second half. * * If the extent we found extends past our * range, we just split and search again. It'll get split * again the next time though. * * If the extent we found is inside our range, we set the * desired bit on it. */ if (state->start < start) { if (state->state & exclusive_bits) { *failed_start = start; err = -EEXIST; goto out; } prealloc = alloc_extent_state_atomic(prealloc); BUG_ON(!prealloc); err = split_state(tree, state, prealloc, start); if (err) extent_io_tree_panic(tree, err); prealloc = NULL; if (err) goto out; if (state->end <= end) { set_state_bits(tree, state, &bits); cache_state(state, cached_state); merge_state(tree, state); if (last_end == (u64)-1) goto out; start = last_end + 1; state = next_state(state); if (start < end && state && state->start == start && !need_resched()) goto hit_next; } goto search_again; } /* * | ---- desired range ---- | * | state | or | state | * * There's a hole, we need to insert something in it and * ignore the extent we found. */ if (state->start > start) { u64 this_end; if (end < last_start) this_end = end; else this_end = last_start - 1; prealloc = alloc_extent_state_atomic(prealloc); BUG_ON(!prealloc); /* * Avoid to free 'prealloc' if it can be merged with * the later extent. */ err = insert_state(tree, prealloc, start, this_end, &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_bit - convert all bits in a given range from one bit to * another * @tree: the io tree to search * @start: the start offset in bytes * @end: the end offset in bytes (inclusive) * @bits: the bits to set in this range * @clear_bits: the bits to clear in this range * @cached_state: state that we're going to cache * @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, 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; again: if (!prealloc && (mask & __GFP_WAIT)) { prealloc = alloc_extent_state(mask); if (!prealloc) return -ENOMEM; } 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); 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) { set_state_bits(tree, state, &bits); cache_state(state, cached_state); state = clear_state_bit(tree, state, &clear_bits, 0); if (last_end == (u64)-1) goto out; start = last_end + 1; if (start < end && state && state->start == start && !need_resched()) goto hit_next; goto search_again; } /* * | ---- desired range ---- | * | state | * or * | ------------- state -------------- | * * We need to split the extent we found, and may flip bits on * second half. * * If the extent we found extends past our * range, we just split and search again. It'll get split * again the next time though. * * If the extent we found is inside our range, we set the * desired bit on it. */ if (state->start < start) { prealloc = alloc_extent_state_atomic(prealloc); if (!prealloc) { err = -ENOMEM; goto out; } err = split_state(tree, state, prealloc, start); if (err) extent_io_tree_panic(tree, err); prealloc = NULL; if (err) goto out; if (state->end <= end) { set_state_bits(tree, state, &bits); cache_state(state, cached_state); state = clear_state_bit(tree, state, &clear_bits, 0); if (last_end == (u64)-1) goto out; start = last_end + 1; if (start < end && state && state->start == start && !need_resched()) goto hit_next; } goto search_again; } /* * | ---- desired range ---- | * | state | or | state | * * There's a hole, we need to insert something in it and * ignore the extent we found. */ if (state->start > start) { u64 this_end; if (end < last_start) this_end = end; else this_end = last_start - 1; prealloc = alloc_extent_state_atomic(prealloc); if (!prealloc) { err = -ENOMEM; goto out; } /* * Avoid to free 'prealloc' if it can be merged with * the later extent. */ err = insert_state(tree, prealloc, start, this_end, &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) { 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); cache_state(prealloc, cached_state); 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 set_extent_defrag(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 | EXTENT_DEFRAG, 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); } 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. If found something, return 0. */ int find_first_extent_bit(struct extent_io_tree *tree, u64 start, u64 *start_ret, u64 *end_ret, int bits, struct extent_state **cached_state) { struct extent_state *state; struct rb_node *n; int ret = 1; spin_lock(&tree->lock); if (cached_state && *cached_state) { state = *cached_state; if (state->end == start - 1 && state->tree) { n = rb_next(&state->rb_node); while (n) { state = rb_entry(n, struct extent_state, rb_node); if (state->state & bits) goto got_it; n = rb_next(n); } free_extent_state(*cached_state); *cached_state = NULL; goto out; } free_extent_state(*cached_state); *cached_state = NULL; } state = find_first_extent_bit_state(tree, start, bits); got_it: if (state) { cache_state(state, cached_state); *start_ret = state->start; *end_ret = state->end; ret = 0; } out: 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 synchronization issues, wait for the data after writing, which * actually prevents the read that triggered the error from finishing. * currently, there can be no more than two copies of every data bit. thus, * exactly one rewrite is required. */ int repair_io_failure(struct btrfs_fs_info *fs_info, u64 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(fs_info, 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); btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS); return -EIO; } printk_ratelimited_in_rcu(KERN_INFO "btrfs read error corrected: ino %lu off %llu " "(dev %s sector %llu)\n", page->mapping->host->i_ino, start, rcu_str_deref(dev->name), sector); bio_put(bio); return 0; } int repair_eb_io_failure(struct btrfs_root *root, struct extent_buffer *eb, int mirror_num) { 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(root->fs_info, 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_fs_info *fs_info; 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) { fs_info = BTRFS_I(inode)->root->fs_info; num_copies = btrfs_num_copies(fs_info, failrec->logical, failrec->len); if (num_copies > 1) { ret = repair_io_failure(fs_info, 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) { 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, 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) { 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_sector=%llu, err=%d, " "mirror=%ld\n", (u64)bio->bi_sector, 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; } 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); if (!ret) { nr++; *bio_flags = this_bio_flag; } } if (ret) { SetPageError(page); unlock_extent(tree, cur, cur + iosize - 1); } 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); } } /* * We need to do this to prevent races in people who check if the eb is * under IO since we can end up having no IO bits set for a short period * of time. */ spin_lock(&eb->refs_lock); if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) { set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags); spin_unlock(&eb->refs_lock); btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN); 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; } else { spin_unlock(&eb->refs_lock); } 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; unsigned long bio_flags = 0; int rw = (epd->sync_io ? WRITE_SYNC : WRITE); int ret = 0; clear_bit(EXTENT_BUFFER_IOERR, &eb->bflags); num_pages = num_extent_pages(eb->start, eb->len); atomic_set(&eb->io_pages, num_pages); if (btrfs_header_owner(eb) == BTRFS_TREE_LOG_OBJECTID) bio_flags = EXTENT_BIO_TREE_LOG; 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, epd->bio_flags, bio_flags); epd->bio_flags = bio_flags; 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, .bio_flags = 0, }; 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; } spin_lock(&mapping->private_lock); if (!PagePrivate(page)) { spin_unlock(&mapping->private_lock); continue; } eb = (struct extent_buffer *)page->private; /* * Shouldn't happen and normally this would be a BUG_ON * but no sense in crashing the users box for something * we can survive anyway. */ if (!eb) { spin_unlock(&mapping->private_lock); WARN_ON(1); continue; } if (eb == prev_eb) { spin_unlock(&mapping->private_lock); continue; } ret = atomic_inc_not_zero(&eb->refs); spin_unlock(&mapping->private_lock); if (!ret) continue; prev_eb = eb; ret = lock_extent_buffer_for_io(eb, 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 *)) { struct inode *inode = mapping->host; int ret = 0; int done = 0; int nr_to_write_done = 0; struct pagevec pvec; int nr_pages; pgoff_t index; pgoff_t end; /* Inclusive */ int scanned = 0; int tag; /* * We have to hold onto the inode so that ordered extents can do their * work when the IO finishes. The alternative to this is failing to add * an ordered extent if the igrab() fails there and that is a huge pain * to deal with, so instead just hold onto the inode throughout the * writepages operation. If it fails here we are freeing up the inode * anyway and we'd rather not waste our time writing out stuff that is * going to be truncated anyway. */ if (!igrab(inode)) return 0; pagevec_init(&pvec, 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; } btrfs_add_delayed_iput(inode); 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, epd->bio_flags); 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, .bio_flags = 0, }; 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, .bio_flags = 0, }; 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, .bio_flags = 0, }; 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; struct page *pagepool[16]; struct page *page; int i = 0; int nr = 0; for (page_idx = 0; page_idx < nr_pages; page_idx++) { 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)) { page_cache_release(page); continue; } pagepool[nr++] = page; if (nr < ARRAY_SIZE(pagepool)) continue; for (i = 0; i < nr; i++) { __extent_read_full_page(tree, pagepool[i], get_extent, &bio, 0, &bio_flags); page_cache_release(pagepool[i]); } nr = 0; } for (i = 0; i < nr; i++) { __extent_read_full_page(tree, pagepool[i], get_extent, &bio, 0, &bio_flags); page_cache_release(pagepool[i]); } 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; } 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; eb->bflags = 0; 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; } struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src) { unsigned long i; struct page *p; struct extent_buffer *new; unsigned long num_pages = num_extent_pages(src->start, src->len); new = __alloc_extent_buffer(NULL, src->start, src->len, GFP_ATOMIC); if (new == NULL) return NULL; for (i = 0; i < num_pages; i++) { p = alloc_page(GFP_ATOMIC); BUG_ON(!p); attach_extent_buffer_page(new, p); WARN_ON(PageDirty(p)); SetPageUptodate(p); new->pages[i] = p; } copy_extent_buffer(new, src, 0, 0, src->len); set_bit(EXTENT_BUFFER_UPTODATE, &new->bflags); set_bit(EXTENT_BUFFER_DUMMY, &new->bflags); return new; } struct extent_buffer *alloc_dummy_extent_buffer(u64 start, unsigned long len) { struct extent_buffer *eb; unsigned long num_pages = num_extent_pages(0, len); unsigned long i; eb = __alloc_extent_buffer(NULL, start, len, GFP_ATOMIC); if (!eb) return NULL; for (i = 0; i < num_pages; i++) { eb->pages[i] = alloc_page(GFP_ATOMIC); if (!eb->pages[i]) goto err; } set_extent_buffer_uptodate(eb); btrfs_set_header_nritems(eb, 0); set_bit(EXTENT_BUFFER_DUMMY, &eb->bflags); return eb; err: for (; i > 0; i--) __free_page(eb->pages[i - 1]); __free_extent_buffer(eb); return NULL; } 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; unsigned long num_pages; struct page *page; int mapped = !test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags); BUG_ON(extent_buffer_under_io(eb)); num_pages = num_extent_pages(eb->start, eb->len); index = start_idx + num_pages; if (start_idx >= index) return; do { index--; page = extent_buffer_page(eb, index); if (page && mapped) { spin_lock(&page->mapping->private_lock); /* * We do this since we'll remove the pages after we've * removed the eb from the radix tree, so we could race * and have this page now attached to the new eb. So * only clear page_private if it's still connected to * this eb. */ if (PagePrivate(page) && page->private == (unsigned long)eb) { BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)); BUG_ON(PageDirty(page)); BUG_ON(PageWriteback(page)); /* * We need to make sure we haven't be attached * to a new eb. */ ClearPagePrivate(page); set_page_private(page, 0); /* One for the page private */ page_cache_release(page); } spin_unlock(&page->mapping->private_lock); } if (page) { /* 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. */ spin_lock(&eb->refs_lock); if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) atomic_inc(&eb->refs); spin_unlock(&eb->refs_lock); } static void mark_extent_buffer_accessed(struct extent_buffer *eb) { 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) 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 */ check_buffer_tree_ref(eb); 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 int release_extent_buffer(struct extent_buffer *eb, gfp_t mask) { WARN_ON(atomic_read(&eb->refs) == 0); if (atomic_dec_and_test(&eb->refs)) { if (test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags)) { spin_unlock(&eb->refs_lock); } else { 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 1; } spin_unlock(&eb->refs_lock); return 0; } 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_DUMMY, &eb->bflags)) atomic_dec(&eb->refs); 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) { WARN(1, KERN_ERR "btrfs bad mapping eb start %llu len %lu, " "wanted %lu %lu\n", (unsigned long long)eb->start, eb->len, start, min_len); 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; } return release_extent_buffer(eb, mask); }