>Da: jeromepou...@gmail.com >Data: 06/12/2010 1.48 >A: "kreij...@inwind.it"<kreij...@inwind.it> >Cc: "chris.ma...@oracle.com"<chris.ma...@oracle.com>, "linux-bt...@vger. kernel.org"<linux-btrfs@vger.kernel.org>, "Felix Blanke"<felixbla...@gmail. com> >Ogg: Re: [PATCH 5/5][REPOST][BTRFS-PROGS] Add the "btrfs filesystem label" command > >On 2010-12-05, at 12:47, Goffredo Baroncelli <kreij...@inwind.it> wrote: > >> Hi all, >> >> this patch adds the command "btrfs filesystem label" to change (or show) the >> label of a filesystem. >> This patch is a subset of the one written previously by Morey Roof. I >> included the user space part only. So it is possible only to change/show a > >label of a *single device* and *umounted* filesystem.
The label is changed on *every devices*. I tested it (on a machine without btrfs) and I confirm that. $ for i in 1 2 ; do dd if=/dev/zero of=img$i bs=1M count=520; done $ sudo losetup -f img1 $ sudo losetup -f img2 $ sudo losetup -a /dev/loop0: [0801]:3965895 (img1) /dev/loop1: [0801]:3965896 (img2) $ sudo mkfs.btrfs -L test1 /dev/loop[01] < removed some messages> $ sudo blkid /dev/loop[01] /dev/loop0: LABEL="test1" UUID="764ac2d3-dd37-4a64-8cfe-db118da8f09f" UUID_SUB="da978017-61c4-488c-9a79-b58271f2b615" TYPE="btrfs" /dev/loop1: LABEL="test1" UUID="764ac2d3-dd37-4a64-8cfe-db118da8f09f" UUID_SUB="83ea15d5-db8f-4605-96ec-77807502627b" TYPE="btrfs" $ sudo btrfs-progs-unstable/btrfs file labe /dev/loop0 failed to open /dev/btrfs-control skipping device registration failed to open /dev/btrfs-control skipping device registration failed to open /dev/btrfs-control skipping device registration failed to open /dev/btrfs-control skipping device registration test1 $ sudo btrfs-progs-unstable/btrfs file labe /dev/loop0 test2 failed to open /dev/btrfs-control skipping device registration failed to open /dev/btrfs-control skipping device registration failed to open /dev/btrfs-control skipping device registration failed to open /dev/btrfs-control skipping device registration $ sudo btrfs file labe /dev/loop1 failed to open /dev/btrfs-control skipping device registration failed to open /dev/btrfs-control skipping device registration failed to open /dev/btrfs-control skipping device registration failed to open /dev/btrfs-control skipping device registration test2 $ sudo blkid /dev/loop[01] /dev/loop0: LABEL="test2" UUID="764ac2d3-dd37-4a64-8cfe-db118da8f09f" UUID_SUB="da978017-61c4-488c-9a79-b58271f2b615" TYPE="btrfs" /dev/loop1: LABEL="test2" UUID="764ac2d3-dd37-4a64-8cfe-db118da8f09f" UUID_SUB="83ea15d5-db8f-4605-96ec-77807502627b" TYPE="btrfs" On the basis of which test your results are different ? >Personally I really don't understand why changing the label of a >mounted filesystem would cause any problem at all. Could someone >explain that to me? Because btrfs rewrite the superblock quite often. So if you change the superblock from the user space when a btrfs filesystem is mounted, it is likely that your change is over-written. Or, worse, the changing of the superblock from the user space may lead to a corruption of the filesystem. >Or at least the applet could include some force option for filesystem >that can't be umounted, for example, root. This request (changing the label of the root filesystem) requires a changing in the kernel side. >Jerome Goffredo >-- >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 -- 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
