Can't mount subvolume with ro option

Sébastien ROHAUT Fri, 27 Jun 2014 13:08:37 -0700

Hi,

In the wiki, it's said we can mount subvolumes with different mountoptions. nosuid, nodev, rw and ro are listed, as valid generic mountoptions.


https://btrfs.wiki.kernel.org/index.php/FAQ#Can_I_mount_subvolumes_with_different_mount_options.3F

But, when I try to mount my subvolume in read only I get an error.

# df
/dev/sdb1             5242880     352    4689856   1% /my_btrfs

# btrfs subvolume list /my_btrfs
ID 257 gen 10 top level 5 path subvol1

# LANG=C mount -t btrfs -o subvol=subvol1,ro /dev/sdb1 /my_btrfs/subvol1_mnt
mount: /dev/sdb1 is already mounted or /my_btrfs/subvol1_mnt busy
       /dev/sdb1 is already mounted on /my_btrfs

nodev and nosuid are working.

Is there an error in the wiki, or do I do something wrong ?

Thanks,

Sebastien ROHAUT

Some infos :

# cat /etc/redhat-release
Fedora release 20 (Heisenbug)

# uname -a

Linux localhost.localdomain 3.14.7-200.fc20.x86_64 #1 SMP Wed Jun 1122:38:05 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux


# btrfs --version
Btrfs v3.14.1

# btrfs fi show
Label: none  uuid: 66e0f120-e478-4cac-b04a-82a0ffc4d6ce
    Total devices 1 FS bytes used 208.00KiB
    devid    1 size 5.00GiB used 548.00MiB path /dev/sdb1

Btrfs v3.14.1

# dmesg|grep -i btrfs
[    2.753052] Btrfs loaded

[ 2.766655] BTRFS: device fsid 66e0f120-e478-4cac-b04a-82a0ffc4d6cedevid 1 transid 9 /dev/sdb1[ 36.382921] BTRFS: device fsid 66e0f120-e478-4cac-b04a-82a0ffc4d6cedevid 1 transid 9 /dev/sdb1

[   36.389497] BTRFS info (device sdb1): disk space caching is enabled
[   36.393462] SELinux: initialized (dev sdb1, type btrfs), uses xattr

[ 860.375237] BTRFS: device fsid 66e0f120-e478-4cac-b04a-82a0ffc4d6cedevid 1 transid 9 /dev/sdb1[ 1141.451952] BTRFS: device fsid 66e0f120-e478-4cac-b04a-82a0ffc4d6cedevid 1 transid 10 /dev/sdb1

[ 1379.802221] BTRFS info (device sdb1): disk space caching is enabled
[ 1513.815988] BTRFS info (device sdb1): disk space caching is enabled

[ 1529.839598] BTRFS: device fsid 66e0f120-e478-4cac-b04a-82a0ffc4d6cedevid 1 transid 11 /dev/sdb1[ 1624.310822] BTRFS: device fsid 66e0f120-e478-4cac-b04a-82a0ffc4d6cedevid 1 transid 11 /dev/sdb1[ 1650.630700] BTRFS: device fsid 66e0f120-e478-4cac-b04a-82a0ffc4d6cedevid 1 transid 11 /dev/sdb1[ 2297.318435] BTRFS: device fsid 66e0f120-e478-4cac-b04a-82a0ffc4d6cedevid 1 transid 11 /dev/sdb1[ 2305.110964] BTRFS: device fsid 66e0f120-e478-4cac-b04a-82a0ffc4d6cedevid 1 transid 11 /dev/sdb1[ 2332.863021] BTRFS: device fsid 66e0f120-e478-4cac-b04a-82a0ffc4d6cedevid 1 transid 12 /dev/sdb1[ 2344.573903] BTRFS: device fsid 66e0f120-e478-4cac-b04a-82a0ffc4d6cedevid 1 transid 12 /dev/sdb1[ 2348.597860] BTRFS: device fsid 66e0f120-e478-4cac-b04a-82a0ffc4d6cedevid 1 transid 12 /dev/sdb1[ 2580.620032] BTRFS: device fsid 66e0f120-e478-4cac-b04a-82a0ffc4d6cedevid 1 transid 13 /dev/sdb1[ 2645.162881] BTRFS: device fsid 66e0f120-e478-4cac-b04a-82a0ffc4d6cedevid 1 transid 13 /dev/sdb1[ 2706.458681] BTRFS: device fsid 66e0f120-e478-4cac-b04a-82a0ffc4d6cedevid 1 transid 13 /dev/sdb1[ 2727.745959] BTRFS: device fsid 66e0f120-e478-4cac-b04a-82a0ffc4d6cedevid 1 transid 13 /dev/sdb1[ 2797.601678] BTRFS: device fsid 66e0f120-e478-4cac-b04a-82a0ffc4d6cedevid 1 transid 13 /dev/sdb1

--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Can't mount subvolume with ro option

Reply via email to