diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/extent_io.c | 114 | ||||
| -rw-r--r-- | fs/btrfs/extent_io.h | 4 |
2 files changed, 49 insertions, 69 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 6e3b326..4c639e1 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -104,7 +104,7 @@ void extent_io_tree_init(struct extent_io_tree *tree, struct address_space *mapping, gfp_t mask) { tree->state = RB_ROOT; - tree->buffer = RB_ROOT; + INIT_RADIX_TREE(&tree->buffer, GFP_ATOMIC); tree->ops = NULL; tree->dirty_bytes = 0; spin_lock_init(&tree->lock); @@ -235,50 +235,6 @@ static inline struct rb_node *tree_search(struct extent_io_tree *tree, return ret; } -static struct extent_buffer *buffer_tree_insert(struct extent_io_tree *tree, - u64 offset, struct rb_node *node) -{ - struct rb_root *root = &tree->buffer; - struct rb_node **p = &root->rb_node; - struct rb_node *parent = NULL; - struct extent_buffer *eb; - - while (*p) { - parent = *p; - eb = rb_entry(parent, struct extent_buffer, rb_node); - - if (offset < eb->start) - p = &(*p)->rb_left; - else if (offset > eb->start) - p = &(*p)->rb_right; - else - return eb; - } - - rb_link_node(node, parent, p); - rb_insert_color(node, root); - return NULL; -} - -static struct extent_buffer *buffer_search(struct extent_io_tree *tree, - u64 offset) -{ - struct rb_root *root = &tree->buffer; - struct rb_node *n = root->rb_node; - struct extent_buffer *eb; - - while (n) { - eb = rb_entry(n, struct extent_buffer, rb_node); - if (offset < eb->start) - n = n->rb_left; - else if (offset > eb->start) - n = n->rb_right; - else - return eb; - } - return NULL; -} - static void merge_cb(struct extent_io_tree *tree, struct extent_state *new, struct extent_state *other) { @@ -3082,6 +3038,7 @@ static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree, eb->len = len; spin_lock_init(&eb->lock); init_waitqueue_head(&eb->lock_wq); + INIT_RCU_HEAD(&eb->rcu_head); #if LEAK_DEBUG spin_lock_irqsave(&leak_lock, flags); @@ -3150,16 +3107,16 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree, struct page *p; struct address_space *mapping = tree->mapping; int uptodate = 1; + int ret; - spin_lock(&tree->buffer_lock); - eb = buffer_search(tree, start); - if (eb) { - atomic_inc(&eb->refs); - spin_unlock(&tree->buffer_lock); + 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_page_accessed(eb->first_page); return eb; } - spin_unlock(&tree->buffer_lock); + rcu_read_unlock(); eb = __alloc_extent_buffer(tree, start, len, mask); if (!eb) @@ -3198,17 +3155,25 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree, if (uptodate) set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags); + ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM); + if (ret) + goto free_eb; + spin_lock(&tree->buffer_lock); - exists = buffer_tree_insert(tree, start, &eb->rb_node); - if (exists) { + ret = radix_tree_insert(&tree->buffer, start >> PAGE_CACHE_SHIFT, eb); + if (ret == -EEXIST) { + exists = radix_tree_lookup(&tree->buffer, + start >> PAGE_CACHE_SHIFT); /* add one reference for the caller */ atomic_inc(&exists->refs); spin_unlock(&tree->buffer_lock); + radix_tree_preload_end(); goto free_eb; } /* add one reference for the tree */ atomic_inc(&eb->refs); spin_unlock(&tree->buffer_lock); + radix_tree_preload_end(); return eb; free_eb: @@ -3224,16 +3189,16 @@ struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree, { struct extent_buffer *eb; - spin_lock(&tree->buffer_lock); - eb = buffer_search(tree, start); - if (eb) - atomic_inc(&eb->refs); - spin_unlock(&tree->buffer_lock); - - if (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_page_accessed(eb->first_page); + return eb; + } + rcu_read_unlock(); - return eb; + return NULL; } void free_extent_buffer(struct extent_buffer *eb) @@ -3863,6 +3828,14 @@ void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset, } } +static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head) +{ + struct extent_buffer *eb = + container_of(head, struct extent_buffer, rcu_head); + + btrfs_release_extent_buffer(eb); +} + int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page) { u64 start = page_offset(page); @@ -3870,23 +3843,30 @@ int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page) int ret = 1; spin_lock(&tree->buffer_lock); - eb = buffer_search(tree, start); + eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT); if (!eb) goto out; - if (atomic_read(&eb->refs) > 1) { + if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) { ret = 0; goto out; } - if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) { + + /* + * set @eb->refs to 0 if it is already 1, and then release the @eb. + * Or go back. + */ + if (atomic_cmpxchg(&eb->refs, 1, 0) != 1) { ret = 0; goto out; } - rb_erase(&eb->rb_node, &tree->buffer); - /* at this point we can safely release the extent buffer */ - btrfs_release_extent_buffer(eb); + radix_tree_delete(&tree->buffer, start >> PAGE_CACHE_SHIFT); out: spin_unlock(&tree->buffer_lock); + + /* at this point we can safely release the extent buffer */ + if (atomic_read(&eb->refs) == 0) + call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu); return ret; } diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h index 5691c7b..1c6d4f3 100644 --- a/fs/btrfs/extent_io.h +++ b/fs/btrfs/extent_io.h @@ -85,7 +85,7 @@ struct extent_io_ops { struct extent_io_tree { struct rb_root state; - struct rb_root buffer; + struct radix_tree_root buffer; struct address_space *mapping; u64 dirty_bytes; spinlock_t lock; @@ -123,7 +123,7 @@ struct extent_buffer { unsigned long bflags; atomic_t refs; struct list_head leak_list; - struct rb_node rb_node; + struct rcu_head rcu_head; /* the spinlock is used to protect most operations */ spinlock_t lock; |
