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linux/fs/btrfs/inode-map.h

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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 <lizf@cn.fujitsu.com>
2011-04-19 19:06:11 -07:00
#ifndef __BTRFS_INODE_MAP
#define __BTRFS_INODE_MAP
void btrfs_init_free_ino_ctl(struct btrfs_root *root);
void btrfs_unpin_free_ino(struct btrfs_root *root);
void btrfs_return_ino(struct btrfs_root *root, u64 objectid);
int btrfs_find_free_ino(struct btrfs_root *root, u64 *objectid);
Btrfs: Support reading/writing on disk free ino cache This is similar to block group caching. We dedicate a special inode in fs tree to save free ino cache. At the very first time we create/delete a file after mount, the free ino cache will be loaded from disk into memory. When the fs tree is commited, the cache will be written back to disk. To keep compatibility, we check the root generation against the generation of the special inode when loading the cache, so the loading will fail if the btrfs filesystem was mounted in an older kernel before. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
2011-04-19 19:33:24 -07:00
int btrfs_save_ino_cache(struct btrfs_root *root,
struct btrfs_trans_handle *trans);
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 <lizf@cn.fujitsu.com>
2011-04-19 19:06:11 -07:00
int btrfs_find_free_objectid(struct btrfs_root *root, u64 *objectid);
#endif
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