Yes. 'device' options work good on boot. (There may be trivial differences, perhaps.) Both 'btrfsctl -a|A' and device option of mount calls a same device collection function, 'scan_one_device' and by this function btrfs knows devices for btrfs. # But, there's no mount option like 'btrfsctl -a', so # option string grows longer and longer as number of # devices increases... Leszek Ciesielski wrote: > On Tue, Dec 1, 2009 at 6:56 AM, TARUISI Hiroaki > <taruishi.hiroak@xxxxxxxxxxxxxx> wrote: >> Btrfs collects block device information when mount or mkfs >> (device_list_add in volumes.c), and know devid-device relation >> by collected information. So, if we make filesystem on plain >> file, btrfs cannot know devid-device relation. As a result, >> btrfs cannot know which is 'devid=n', and mount fails. Same as >> this, if collected relation is cleared by shutdown, mount fails. >> >> If wlee need to mount a filesystem without fail(cf, /etc/fstab line), >> we should specify 'device' options for every devices(except mount >> target device) like this. >> >> # mount -t btrfs -o device=/dev/loop2,device=/dev/loop3, >> device=/dev/loop4 /dev/loop1 /mnt/ >> (when a filesystem is constructed by /dev/loop[1-4]) >> >> Regards, >> taruisi > > Would this option ["mount -t btrfs -o device=/dev/sdb2 /dev/sda2 > /mnt"] work on boot, bypasing the need for "btrfsctl -a" to mount a > multi-device filesystem? > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- taruisi -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
