From 581bb050941b4f220f84d3e5ed6dace3d42dd382 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Wed, 20 Apr 2011 10:06:11 +0800 Subject: Btrfs: Cache free inode numbers in memory Currently btrfs stores the highest objectid of the fs tree, and it always returns (highest+1) inode number when we create a file, so inode numbers won't be reclaimed when we delete files, so we'll run out of inode numbers as we keep create/delete files in 32bits machines. This fixes it, and it works similarly to how we cache free space in block cgroups. We start a kernel thread to read the file tree. By scanning inode items, we know which chunks of inode numbers are free, and we cache them in an rb-tree. Because we are searching the commit root, we have to carefully handle the cross-transaction case. The rb-tree is a hybrid extent+bitmap tree, so if we have too many small chunks of inode numbers, we'll use bitmaps. Initially we allow 16K ram of extents, and a bitmap will be used if we exceed this threshold. The extents threshold is adjusted in runtime. Signed-off-by: Li Zefan --- fs/btrfs/free-space-cache.h | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) (limited to 'fs/btrfs/free-space-cache.h') diff --git a/fs/btrfs/free-space-cache.h b/fs/btrfs/free-space-cache.h index a64a23fae1eb..af06e6b6ceaa 100644 --- a/fs/btrfs/free-space-cache.h +++ b/fs/btrfs/free-space-cache.h @@ -64,15 +64,25 @@ int btrfs_write_out_cache(struct btrfs_root *root, struct btrfs_trans_handle *trans, struct btrfs_block_group_cache *block_group, struct btrfs_path *path); + void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group); -int btrfs_add_free_space(struct btrfs_block_group_cache *block_group, - u64 bytenr, u64 size); +int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl, + u64 bytenr, u64 size); +static inline int +btrfs_add_free_space(struct btrfs_block_group_cache *block_group, + u64 bytenr, u64 size) +{ + return __btrfs_add_free_space(block_group->free_space_ctl, + bytenr, size); +} int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group, u64 bytenr, u64 size); +void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl); void btrfs_remove_free_space_cache(struct btrfs_block_group_cache - *block_group); + *block_group); u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group, u64 offset, u64 bytes, u64 empty_size); +u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root); void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group, u64 bytes); int btrfs_find_space_cluster(struct btrfs_trans_handle *trans, -- cgit v1.2.3