Re: Internal error xfs_sb_read_verify at line 726

[Dave Chinner <david@fromorbit.com>]

On Mon, May 06, 2013 at 04:48:39PM -0500, Eric Sandeen wrote:
> On 5/6/13 3:49 PM, Eric Sandeen wrote:
> ...
> 
> > Interesting, so [mount] really does try to mount by successive fs types.
> > 
> > I wonder when that behavior changed (my util-linux-ng 2.17 on RHEL6 doesn't do this)
> > 
> > I'll take a look.
> 
> Just to satisfy my curiosity:
> 
> commit c6c98f93f5e4b3fb9a8b51ed2ef9967793df7b1c
> Author: Karel Zak <kzak@redhat.com>
> Date:   Mon Mar 15 13:46:43 2010 +0100
> 
>     mount: report ambivalent FS detection, improve brute force detection
>     
>     The ambivalent probing result should be properly reported and user
>     should be informed that the problem is possible to bypass by "-t
>     <type>" or resolved by wipefs(8).
>     
>     The mount(8) command uses a brute force stage (calls mount(2) for all
>     /{proc,etc}/fylesystems) if there is not any other way how to detect
>     the filesystem type. The brute force stage should not be restricted by
>     libblkid. It's possible that libblkid is not able to detect slightly
>     corrupted filesystem, but kernel is able to mount such filesystem.
>     
>     Note that the brute force stage should not be used if libblkid returns
>     ambivalent probing result. In this case user's intervention is required
>     (e.g. mount -t <type>).
>     
>     Reported-by: Mike Frysinger <vapier@gentoo.org>
>     Signed-off-by: Karel Zak <kzak@redhat.com>
> 
> So we're getting into xfs mount with an actual "-t xfs" equivalent,
> and not going down the "silent" paths.

That's just completely broken mount behaviour. Probing is supposed
to be *silent*, and this is just downright obnxious. Here's what I
get in my log after doing this:

# dd if=/dev/zero of=/dev/vdb bs=512 count=1
# blkid -g
# mount  /dev/vdb /mnt/scratch/
mount: you must specify the filesystem type
$ dmesg
......
[83182.775467] REISERFS warning (device vdb): sh-2021 reiserfs_fill_super: can not find reiserfs on vdb
[83182.778473] EXT3-fs (vdb): error: can't find ext3 filesystem on dev vdb.
[83182.781135] EXT2-fs (vdb): error: can't find an ext2 filesystem on dev vdb.
[83182.783524] EXT4-fs (vdb): VFS: Can't find ext4 filesystem
[83182.787392] cramfs: wrong magic
[83182.788926] SQUASHFS error: Can't find a SQUASHFS superblock on vdb
[83182.791150] VFS: Can't find a Minix filesystem V1 | V2 | V3 on device vdb.
[83182.793737] FAT-fs (vdb): bogus number of reserved sectors
[83182.795202] FAT-fs (vdb): Can't find a valid FAT filesystem
[83182.797268] FAT-fs (vdb): bogus number of reserved sectors
[83182.798984] FAT-fs (vdb): Can't find a valid FAT filesystem
[83182.801236] BFS-fs: bfs_fill_super(): No BFS filesystem on vdb (magic=00000000)
[83182.846555] ISOFS: Unable to identify CD-ROM format.
[83182.849136] hfs: unable to find HFS+ superblock
[83182.851164] hfs: can't find a HFS filesystem on dev vdb.
[83182.853204] vxfs: WRONG superblock magic
[83182.856855] VFS: unable to find oldfs superblock on device vdb
[83182.858930] VFS: could not find a valid V7 on vdb.
[83182.860938] NTFS-fs error (device vdb): read_ntfs_boot_sector(): Primary boot sector is invalid.
[83182.863247] NTFS-fs error (device vdb): read_ntfs_boot_sector(): Mount option errors=recover not used. Aborting without trying to recover.
[83182.866563] NTFS-fs error (device vdb): ntfs_fill_super(): Not an NTFS volume.
[83182.873922] AFFS: No valid root block on device vdb
[83182.875697] VFS: Can't find a romfs filesystem on dev vdb.
[83182.877823] qnx4: wrong fsid in superblock.
[83182.884286] UDF-fs: warning (device vdb): udf_load_vrs: No VRS found
[83182.886217] UDF-fs: Rescanning with blocksize 2048
[83182.891965] UDF-fs: warning (device vdb): udf_load_vrs: No VRS found
[83182.893730] UDF-fs: warning (device vdb): udf_fill_super: No partition found (1)
[83182.896216] omfs: Invalid superblock (0)
[83182.898937] XFS (vdb): bad magic number
[83182.900150] ffff88007bbce000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[83182.902676] ffff88007bbce010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[83182.905281] ffff88007bbce020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[83182.907845] ffff88007bbce030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[83182.910559] XFS (vdb): Internal error xfs_sb_read_verify at line 726 of file fs/xfs/xfs_mount.c.  Caller 0xffffffff814645e5
[83182.910559]
[83182.914377] Pid: 1064, comm: kworker/0:1H Not tainted 3.9.0-rc8-dgc+ #575
[83182.916499] Call Trace:
[83182.917245]  [<ffffffff8146761f>] xfs_error_report+0x3f/0x50
[83182.918762]  [<ffffffff814645e5>] ? xfs_buf_iodone_work+0xc5/0xf0
[83182.920113]  [<ffffffff8146768e>] xfs_corruption_error+0x5e/0x90
[83182.921351]  [<ffffffff814cf50a>] xfs_sb_read_verify+0x11a/0x130
[83182.922692]  [<ffffffff814645e5>] ? xfs_buf_iodone_work+0xc5/0xf0
[83182.923972]  [<ffffffff810b6555>] ? finish_task_switch+0x65/0x100
[83182.925343]  [<ffffffff814645e5>] xfs_buf_iodone_work+0xc5/0xf0
[83182.926634]  [<ffffffff810a35d0>] process_one_work+0x170/0x400
[83182.927832]  [<ffffffff810a4f26>] worker_thread+0x116/0x390
[83182.929116]  [<ffffffff810a4e10>] ? busy_worker_rebind_fn+0xb0/0xb0
[83182.930460]  [<ffffffff810aadd8>] kthread+0xd8/0xe0
[83182.931469]  [<ffffffff810aad00>] ? kthread_create_on_node+0x140/0x140
[83182.932921]  [<ffffffff81c23dec>] ret_from_fork+0x7c/0xb0
[83182.934047]  [<ffffffff810aad00>] ? kthread_create_on_node+0x140/0x140
[83182.935489] XFS (vdb): Corruption detected. Unmount and run xfs_repair
[83182.937045] XFS (vdb): SB validate failed with error 22.
[83182.940181] NILFS: Can't find nilfs on dev vdb.
[83182.941321] BeFS(vdb): No write support. Marking filesystem read-only
[83182.943036] BeFS(vdb): invalid magic header
[83182.946526] (mount,23815,1):ocfs2_fill_super:1039 ERROR: superblock probe failed!
[83182.948515] (mount,23815,1):ocfs2_fill_super:1230 ERROR: status = -22
[83182.951606] GFS2: not a GFS2 filesystem
[83182.952898] GFS2: gfs2 mount does not exist
[83182.954425] F2FS-fs (vdb): Magic Mismatch, valid(0xf2f52010) - read(0x49474158)
[83182.956540] F2FS-fs (vdb): Can't find a valid F2FS filesystem in first superblock
[83182.959044] F2FS-fs (vdb): Magic Mismatch, valid(0xf2f52010) - read(0x0)
[83182.960894] F2FS-fs (vdb): Can't find a valid F2FS filesystem in second superblock


I've removed logfs from my kernels because this probing causes
logfs to oops the kernel...

> I'll send the patch.

I think that mount needs fixing, not XFS. mount needs to be doing
silent mounts when doing this brute forcing, not noisy, explicit
mounts that we expect to throw errors if there is a problem.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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