diff options
Diffstat (limited to 'fs/btrfs')
-rw-r--r-- | fs/btrfs/extent_map.c | 48 | ||||
-rw-r--r-- | fs/btrfs/extent_map.h | 2 | ||||
-rw-r--r-- | fs/btrfs/inode.c | 10 |
3 files changed, 59 insertions, 1 deletions
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index 5bc7a0d325e..2c726b7b9fa 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -367,6 +367,54 @@ out: } /** + * search_extent_mapping - find a nearby extent map + * @tree: tree to lookup in + * @start: byte offset to start the search + * @len: length of the lookup range + * + * Find and return the first extent_map struct in @tree that intersects the + * [start, len] range. + * + * If one can't be found, any nearby extent may be returned + */ +struct extent_map *search_extent_mapping(struct extent_map_tree *tree, + u64 start, u64 len) +{ + struct extent_map *em; + struct rb_node *rb_node; + struct rb_node *prev = NULL; + struct rb_node *next = NULL; + + rb_node = __tree_search(&tree->map, start, &prev, &next); + if (!rb_node && prev) { + em = rb_entry(prev, struct extent_map, rb_node); + goto found; + } + if (!rb_node && next) { + em = rb_entry(next, struct extent_map, rb_node); + goto found; + } + if (!rb_node) { + em = NULL; + goto out; + } + if (IS_ERR(rb_node)) { + em = ERR_PTR(PTR_ERR(rb_node)); + goto out; + } + em = rb_entry(rb_node, struct extent_map, rb_node); + goto found; + + em = NULL; + goto out; + +found: + atomic_inc(&em->refs); +out: + return em; +} + +/** * remove_extent_mapping - removes an extent_map from the extent tree * @tree: extent tree to remove from * @em: extent map beeing removed diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h index d3d442f4bbb..ab6d74b6e64 100644 --- a/fs/btrfs/extent_map.h +++ b/fs/btrfs/extent_map.h @@ -60,4 +60,6 @@ void free_extent_map(struct extent_map *em); int __init extent_map_init(void); void extent_map_exit(void); int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len); +struct extent_map *search_extent_mapping(struct extent_map_tree *tree, + u64 start, u64 len); #endif diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 941f1b71cd2..81ba6654c33 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -726,6 +726,15 @@ static noinline int cow_file_range(struct inode *inode, BUG_ON(disk_num_bytes > btrfs_super_total_bytes(&root->fs_info->super_copy)); + + read_lock(&BTRFS_I(inode)->extent_tree.lock); + em = search_extent_mapping(&BTRFS_I(inode)->extent_tree, + start, num_bytes); + if (em) { + alloc_hint = em->block_start; + free_extent_map(em); + } + read_unlock(&BTRFS_I(inode)->extent_tree.lock); btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0); while (disk_num_bytes > 0) { @@ -738,7 +747,6 @@ static noinline int cow_file_range(struct inode *inode, em = alloc_extent_map(GFP_NOFS); em->start = start; em->orig_start = em->start; - ram_size = ins.offset; em->len = ins.offset; |