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authorLi Zefan <lizf@cn.fujitsu.com>2011-04-20 06:06:11 +0400
committerLi Zefan <lizf@cn.fujitsu.com>2011-04-25 12:46:04 +0400
commit581bb050941b4f220f84d3e5ed6dace3d42dd382 (patch)
tree5ebd56af5eb3612f508419b188dfc18e959e7c94 /fs/btrfs/inode-map.h
parent34d52cb6c50b5a43901709998f59fb1c5a43dc4a (diff)
downloadlinux-581bb050941b4f220f84d3e5ed6dace3d42dd382.tar.xz
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>
Diffstat (limited to 'fs/btrfs/inode-map.h')
-rw-r--r--fs/btrfs/inode-map.h11
1 files changed, 11 insertions, 0 deletions
diff --git a/fs/btrfs/inode-map.h b/fs/btrfs/inode-map.h
new file mode 100644
index 000000000000..eb918451b492
--- /dev/null
+++ b/fs/btrfs/inode-map.h
@@ -0,0 +1,11 @@
+#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);
+
+int btrfs_find_free_objectid(struct btrfs_root *root, u64 *objectid);
+
+#endif