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fs: remove FS_COW_FL 

FS_COW_FL and FS_NOCOW_FL were newly introduced to control per file
COW in btrfs, but FS_NOCOW_FL is sufficient.

The fact is we don't have corresponding BTRFS_INODE_COW flag.

COW is default, and FS_NOCOW_FL can be used to switch off COW for
a single file.

If we mount btrfs with nodatacow, a newly created file will be set with
the FS_NOCOW_FL flag. So to turn on COW for it, we can just clear the
FS_NOCOW_FL flag.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Li Zefan 2011-04-15 03:02:49 +00:00 committed by Chris Mason
parent 1aba86d67f
commit e1e8fb6a1f
2 changed files with 6 additions and 10 deletions
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15
fs/btrfs/ioctl.c
View File

@ -144,16 +144,13 @@ static int check_flags(unsigned int flags)
if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
FS_NOATIME_FL | FS_NODUMP_FL | \
FS_SYNC_FL | FS_DIRSYNC_FL | \
FS_NOCOMP_FL | FS_COMPR_FL | \
FS_NOCOW_FL | FS_COW_FL))
FS_NOCOMP_FL | FS_COMPR_FL |
FS_NOCOW_FL))
return -EOPNOTSUPP;
if ((flags & FS_NOCOMP_FL) && (flags & FS_COMPR_FL))
return -EINVAL;
if ((flags & FS_NOCOW_FL) && (flags & FS_COW_FL))
return -EINVAL;
return 0;
}
@ -218,6 +215,10 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
ip->flags |= BTRFS_INODE_DIRSYNC;
else
ip->flags &= ~BTRFS_INODE_DIRSYNC;
if (flags & FS_NOCOW_FL)
ip->flags |= BTRFS_INODE_NODATACOW;
else
ip->flags &= ~BTRFS_INODE_NODATACOW;
/*
* The COMPRESS flag can only be changed by users, while the NOCOMPRESS
@ -231,10 +232,6 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
ip->flags |= BTRFS_INODE_COMPRESS;
ip->flags &= ~BTRFS_INODE_NOCOMPRESS;
}
if (flags & FS_NOCOW_FL)
ip->flags |= BTRFS_INODE_NODATACOW;
else if (flags & FS_COW_FL)
ip->flags &= ~BTRFS_INODE_NODATACOW;
trans = btrfs_join_transaction(root, 1);
BUG_ON(IS_ERR(trans));

1
include/linux/fs.h
View File

@ -365,7 +365,6 @@ struct inodes_stat_t {
#define FS_EXTENT_FL 0x00080000 /* Extents */
#define FS_DIRECTIO_FL 0x00100000 /* Use direct i/o */
#define FS_NOCOW_FL 0x00800000 /* Do not cow file */
#define FS_COW_FL 0x02000000 /* Cow file */
#define FS_RESERVED_FL 0x80000000 /* reserved for ext2 lib */
#define FS_FL_USER_VISIBLE 0x0003DFFF /* User visible flags */