[dm-devel] [PATCH] deadlock with suspend and quotas
Mikulas Patocka
mpatocka at redhat.com
Wed Nov 30 06:52:22 UTC 2011
> > dm-ioctl.h:
> > /*
> > * Set this to avoid attempting to freeze any filesystem when suspending.
> > */
> > #define DM_SKIP_LOCKFS_FLAG (1 << 10) /* In */
> Thanks. I was now checking in detail and indeed FIFREEZE fails if
> ->freeze_fs is not set. And only xfs, ext3, ext4, reiserfs, jfs, nilfs2,
> and gfs2 provide this function. So I was correct in assuming that when
> filesystem supports FIFREEZE it must make sure no modifications happen to
> the filesystem. So I believe that my original plan for sync to skip frozen
> filesystem is correct.
>
> Honza
LVM doesn't suspend with FIFREEZE, it calls freeze_bdev directly from
drivers/md/dm.c (and it works for all filesystems, including ext2). So if
you skip sync of frozen filesystems, you introduce a data corruption if
someone takes a snapshot of ext2.
Mikulas
More information about the dm-devel
mailing list