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authorLiu Bo <liubo2009@cn.fujitsu.com>2011-03-22 06:12:20 -0400
committerroot <Chris Mason chris.mason@oracle.com>2011-03-28 05:37:41 -0400
commit75e7cb7fe0c391561bd3af36515be3f3c64a04c6 (patch)
tree3738481e2db10b2904a4434e4ca42d326da02be7 /fs/btrfs/disk-io.c
parent32471f6e1983922473573da62cbee58699574aa4 (diff)
Btrfs: Per file/directory controls for COW and compression
Data compression and data cow are controlled across the entire FS by mount options right now. ioctls are needed to set this on a per file or per directory basis. This has been proposed previously, but VFS developers wanted us to use generic ioctls rather than btrfs-specific ones. According to Chris's comment, there should be just one true compression method(probably LZO) stored in the super. However, before this, we would wait for that one method is stable enough to be adopted into the super. So I list it as a long term goal, and just store it in ram today. After applying this patch, we can use the generic "FS_IOC_SETFLAGS" ioctl to control file and directory's datacow and compression attribute. NOTE: - The compression type is selected by such rules: If we mount btrfs with compress options, ie, zlib/lzo, the type is it. Otherwise, we'll use the default compress type (zlib today). v1->v2: - rebase to the latest btrfs. v2->v3: - fix a problem, i.e. when a file is set NOCOW via mount option, then this NOCOW will be screwed by inheritance from parent directory. Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/disk-io.c')
-rw-r--r--fs/btrfs/disk-io.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 2bdb124333ab..125639ddaffe 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1854,6 +1854,12 @@ struct btrfs_root *open_ctree(struct super_block *sb,
1854 1854
1855 btrfs_check_super_valid(fs_info, sb->s_flags & MS_RDONLY); 1855 btrfs_check_super_valid(fs_info, sb->s_flags & MS_RDONLY);
1856 1856
1857 /*
1858 * In the long term, we'll store the compression type in the super
1859 * block, and it'll be used for per file compression control.
1860 */
1861 fs_info->compress_type = BTRFS_COMPRESS_ZLIB;
1862
1857 ret = btrfs_parse_options(tree_root, options); 1863 ret = btrfs_parse_options(tree_root, options);
1858 if (ret) { 1864 if (ret) {
1859 err = ret; 1865 err = ret;