First thanks alot to Kay and Goffredo! But I have another question. I read that the current tools cannot display subvolumes, but one should still be able to mount them. If I try I get an error message:> mount -t btrfs -o subvol=root.2010-01-07 /dev/sda3 /savemount: /dev/sda3 is not a valid block device root.2010-01-07 is a snapshot of the /root-directory /save is an empty directory used for mounting backups taken (successfully) with the following command:> btrfsctl -s root.2010-01-07 /rootWhat am I doing wrong? Isn''t it possible to mount the whole filesystem and a subvolume at the same time? Greetings, Michael -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Saturday 09 January 2010 14:07:57 Dipl.-Ing. Michael Niederle wrote:> First thanks alot to Kay and Goffredo! > > But I have another question. > > I read that the current tools cannot display subvolumes, but one should > still > > be able to mount them. If I try I get an error message: > > mount -t btrfs -o subvol=root.2010-01-07 /dev/sda3 /save > > mount: /dev/sda3 is not a valid block deviceDoes /dev/sda3 actually exist? Is this a USB device which may have changed its name (now sdb3, or even sdc3) after plugging it out and back in again? Bye... Dirk -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi, Dirk!> Does /dev/sda3 actually exist?/dev/sda3 does exist; it is an btrfs formatted partition containing my root file system:> mount... /dev/sda3 on / type btrfs (rw,relatime,noacl) ... Greetings, Michael @Johannes: I will recreate the /dev/brtfs-control device node in the startup scripts using the information from /sys/class/misc/btrfs-control/dev - thanks! -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sat, Jan 09, 2010 at 03:07:57PM +0100, Dipl.-Ing. Michael Niederle wrote:> I read that the current tools cannot display subvolumes, but one should still > be able to mount them. If I try I get an error message: > > > mount -t btrfs -o subvol=root.2010-01-07 /dev/sda3 /save > mount: /dev/sda3 is not a valid block device > > root.2010-01-07 is a snapshot of the /root-directory > taken (successfully) with the following command: > > btrfsctl -s root.2010-01-07 /rootSnapshots aren''t subvolumes. You create mountable subvolumes with btrfsctl -S -- Tomasz Torcz RIP is irrevelant. Spoofing is futile. xmpp: zdzichubg@chrome.pl Your routes will be aggreggated. -- Alex Yuriev -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Saturday 09 January 2010, Dipl.-Ing. Michael Niederle wrote:> First thanks alot to Kay and Goffredo! > > But I have another question. > > I read that the current tools cannot display subvolumes, but one shouldstill> be able to mount them. If I try I get an error message: > > > mount -t btrfs -o subvol=root.2010-01-07 /dev/sda3 /save > mount: /dev/sda3 is not a valid block device > > root.2010-01-07 is a snapshot of the /root-directory > > /save is an empty directory used for mounting backups > > taken (successfully) with the following command: > > > btrfsctl -s root.2010-01-07 /root > > What am I doing wrong? Isn''t it possible to mount the whole filesystem and a > subvolume at the same time?It is possible. I do that on my machine. The magic part is that the subvolume/snapshot (are the same thing) has to be under the / of the filesystem. ghigo@arakne:/tmp$ mkdir test ghigo@arakne:/tmp$ mkdir test-snap ghigo@arakne:/tmp$ sudo mount -o /dev/sdc test ghigo@arakne:/tmp$ mount | grep btrfs /dev/sdc on /tmp/test type btrfs (rw) ghigo@arakne:/tmp$ cd test ghigo@arakne:/tmp/test$ sudo mkdir a ghigo@arakne:/tmp/test$ sudo btrfsctl -s a/snap-on-subdir . operation complete Btrfs Btrfs v0.19 ghigo@arakne:/tmp/test$ sudo btrfsctl -s snap-of-root . operation complete Btrfs Btrfs v0.19 ghigo@arakne:/tmp/test$ cd .. ghigo@arakne:/tmp$ sudo mount -o subvol=snap-on-subdir /dev/sdc test-snap/ mount: /dev/sdc is not a valid block device ghigo@arakne:/tmp$ sudo mount -o subvol=snap-of-root /dev/sdc test-snap/ ghigo@arakne:/tmp$ mount | grep btrfs /dev/sdc on /tmp/test type btrfs (rw) /dev/sdc on /tmp/test-snap type btrfs (rw,subvol=snap-of-root) Note: - both the root of the btrfs filesystem and its snapshot are mounted at the same time - if a subvolume/snapshot not placed in the root is mounted an error is returned (/dev/sdX is not a valid block device)> Greetings, MichaelGoffredo> -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >-- gpg key@ keyserver.linux.it: Goffredo Baroncelli (ghigo) <kreijackATinwind.it> Key fingerprint = 4769 7E51 5293 D36C 814E C054 BF04 F161 3DC5 0512 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html