Neil Brown <neilb@xxxxxxx> writes: > On Monday May 15, jdc@xxxxxx wrote: >> I accidentally ran mkswap on an md raid1 device which had a mounted >> ext3 filesystem on it. I also did a swapon, but I don't think >> anything was written to swap before I noticed the mistake. How much >> of the partition is toast, and is it something e2fsck might fix? > > I think (and an strace seems to confirm) that mkswap only writes in > the first 4k of the device. This will have held the superblock, but > there is always at least one backup - I think it is as block 8193. > But 'fsck -n' should help you out, though you might need > 'fsck.ext2 -n' as 'fsck' might think it is a swap device... Thanks for the quick response! I tried e2fsck, and it found the backup superblock on its own. I answered yes to dozens of questions, and the filesystem is now intact. > Ofcourse, if the filesystem is mounted, then unmounting the filesystem > should write the superblock, which might fix any corruption you > caused.. I decided to do a Alt-Sysrq-u Alt-Sysrq-b reboot to minimize what was written to disk when things were already messed up. > Adrian: You seem to be the MAINTAINER of mkswap.. any chance of > opening for O_EXCL as well as O_RDWR. That would make it a lot safer. That would have saved me lots of worry! Thanks again, Dan - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
