2011-04-15 02:59:41

by Li Zefan

Subject: [PATCH 1/3] 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 <[email protected]>
---
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

2011-04-15 02:59:58

by Li Zefan

Subject: [PATCH 2/3] Btrfs: fix FS_IOC_GETFLAGS ioctl

As we've added per file compression/cow support.

Signed-off-by: Li Zefan <[email protected]>
---
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

2011-04-15 03:00:10

by Li Zefan

Subject: [PATCH 3/3] Btrfs: fix FS_IOC_SETFLAGS ioctl

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 <[email protected]>
---
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

2011-05-03 09:08:17

by Li Zefan

Subject: Re: [PATCH 1/3] fs: remove FS_COW_FL

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 <[email protected]>
> ---
> 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 */

2011-05-03 11:20:37

by Chris Mason

Subject: Re: [PATCH 1/3] fs: remove FS_COW_FL

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