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>
---
fs/btrfs/ioctl.c | 15 ++++++---------
include/linux/fs.h | 1 -
2 files changed, 6 insertions(+), 10 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index f580a3a..3240dd9 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -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));
diff --git a/include/linux/fs.h b/include/linux/fs.h
index de9dd81..56a4141 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -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 */
--
1.7.3.1
As we''ve added per file compression/cow support. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> --- fs/btrfs/ioctl.c | 7 +++++++ 1 files changed, 7 insertions(+), 0 deletions(-) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 3240dd9..aeabf6b 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -81,6 +81,13 @@ static unsigned int btrfs_flags_to_ioctl(unsigned int flags) iflags |= FS_NOATIME_FL; if (flags & BTRFS_INODE_DIRSYNC) iflags |= FS_DIRSYNC_FL; + if (flags & BTRFS_INODE_NODATACOW) + iflags |= FS_NOCOW_FL; + + if ((flags & BTRFS_INODE_COMPRESS) && !(flags & BTRFS_INODE_NOCOMPRESS)) + iflags |= FS_COMPR_FL; + else if (flags & BTRFS_INODE_NOCOMPRESS) + iflags |= FS_NOCOMP_FL; return iflags; } -- 1.7.3.1
Steps to reproduce the bug:
- Call FS_IOC_SETLFAGS ioctl with flags=FS_COMPR_FL
- Call FS_IOC_SETFLAGS ioctl with flags=0
- Call FS_IOC_GETFLAGS ioctl, and you''ll see FS_COMPR_FL is still
set!
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
fs/btrfs/ioctl.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index aeabf6b..3e7031d 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -238,6 +238,8 @@ static int btrfs_ioctl_setflags(struct file *file, void
__user *arg)
} else if (flags & FS_COMPR_FL) {
ip->flags |= BTRFS_INODE_COMPRESS;
ip->flags &= ~BTRFS_INODE_NOCOMPRESS;
+ } else {
+ ip->flags &= ~(BTRFS_INODE_COMPRESS | BTRFS_INODE_NOCOMPRESS);
}
trans = btrfs_join_transaction(root, 1);
--
1.7.3.1
Any comments? If this patch is acceptable, it should be queued for .39? since fs.h is exported to userspace. Li Zefan wrote:> 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> > --- > fs/btrfs/ioctl.c | 15 ++++++--------- > include/linux/fs.h | 1 - > 2 files changed, 6 insertions(+), 10 deletions(-) > > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c > index f580a3a..3240dd9 100644 > --- a/fs/btrfs/ioctl.c > +++ b/fs/btrfs/ioctl.c > @@ -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)); > diff --git a/include/linux/fs.h b/include/linux/fs.h > index de9dd81..56a4141 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -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 */
Excerpts from Li Zefan''s message of 2011-05-03 05:11:44 -0400:> Any comments? If this patch is acceptable, it should be queued for .39? > since fs.h is exported to userspace. > > Li Zefan wrote: > > FS_COW_FL and FS_NOCOW_FL were newly introduced to control per file > > COW in btrfs, but FS_NOCOW_FL is sufficient. > >Good point, I''ll send this in. -chris