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>
1 file changed