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author | Harald Hoyer <harald@redhat.com> | 2013-11-19 11:36:05 +0100 |
---|---|---|
committer | Chris Mason <clm@fb.com> | 2014-04-10 13:32:50 -0700 |
commit | 0723a0473fb48a1c93b113a28665b64ce5faf35a (patch) | |
tree | 59f5dc31dd82e06dc8d836b4544e676c7b85d23d /fs/btrfs | |
parent | 36523e95129c0e69bf1592cd009261b1c6d96e77 (diff) | |
download | linux-stable-0723a0473fb48a1c93b113a28665b64ce5faf35a.tar.gz linux-stable-0723a0473fb48a1c93b113a28665b64ce5faf35a.tar.bz2 linux-stable-0723a0473fb48a1c93b113a28665b64ce5faf35a.zip |
btrfs: allow mounting btrfs subvolumes with different ro/rw options
Given the following /etc/fstab entries:
/dev/sda3 /mnt/foo btrfs subvol=foo,ro 0 0
/dev/sda3 /mnt/bar btrfs subvol=bar,rw 0 0
you can't issue:
$ mount /mnt/foo
$ mount /mnt/bar
You would have to do:
$ mount /mnt/foo
$ mount -o remount,rw /mnt/foo
$ mount --bind -o remount,ro /mnt/foo
$ mount /mnt/bar
or
$ mount /mnt/bar
$ mount --rw /mnt/foo
$ mount --bind -o remount,ro /mnt/foo
With this patch you can do
$ mount /mnt/foo
$ mount /mnt/bar
$ cat /proc/self/mountinfo
49 33 0:41 /foo /mnt/foo ro,relatime shared:36 - btrfs /dev/sda3 rw,ssd,space_cache
87 33 0:41 /bar /mnt/bar rw,relatime shared:74 - btrfs /dev/sda3 rw,ssd,space_cache
Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r-- | fs/btrfs/super.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index d4878ddba87a..994c40955315 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -66,6 +66,8 @@ static const struct super_operations btrfs_super_ops; static struct file_system_type btrfs_fs_type; +static int btrfs_remount(struct super_block *sb, int *flags, char *data); + static const char *btrfs_decode_error(int errno) { char *errstr = "unknown"; @@ -1185,6 +1187,26 @@ static struct dentry *mount_subvol(const char *subvol_name, int flags, mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs); kfree(newargs); + + if (PTR_RET(mnt) == -EBUSY) { + if (flags & MS_RDONLY) { + mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY, device_name, + newargs); + } else { + int r; + mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY, device_name, + newargs); + if (IS_ERR(mnt)) + return ERR_CAST(mnt); + + r = btrfs_remount(mnt->mnt_sb, &flags, NULL); + if (r < 0) { + /* FIXME: release vfsmount mnt ??*/ + return ERR_PTR(r); + } + } + } + if (IS_ERR(mnt)) return ERR_CAST(mnt); |