#259 lost all data on disk after kernel crash

[Loic Dachary]

<pre>
USB disk

Vanilia Debian kernel

Linux call 2.6.22-3-vserver-686 #1 SMP Mon Nov 12 11:07:35 UTC 2007 i686 GNU/Linux

ERROR: (device sdb3): DT_GETPAGE: dtree page corrupt
[<f8f2d257>] __get_metapage+0x43/0x34d [jfs]
[<f8f2cc5a>] release_metapage+0x11e/0x12a [jfs]
[<f8f25c26>] dtReadFirst+0x7e/0x1f1 [jfs]
[<f8f2897c>] jfs_readdir+0x2b8/0xfbd [jfs]
[<c015aeb2>] get_page_from_freelist+0x290/0x327
[<c017dd30>] filldir64+0x0/0xc5
[<f8f34d51>] jfs_check_acl+0x20/0x5f [jfs]
[<c015af9b>] __alloc_pages+0x52/0x294
[<c01796ad>] permission+0x20c/0x245
[<c016341d>] __handle_mm_fault+0x6c6/0xc55
[<c017a54d>] may_open+0xa6/0x25d
[<c011aeea>] do_page_fault+0x2d0/0x58e
[<c017df11>] vfs_readdir+0x63/0x8d
[<c017dd30>] filldir64+0x0/0xc5
[<c017df9e>] sys_getdents64+0x63/0xa5
[<c0103d1a>] sysenter_past_esp+0x6b/0xa1
=======================

umount

fsck says:

call:/home/loic# fsck /sdb3
fsck 1.40.2 (12-Jul-2007)
fsck.jfs version 1.1.11, 05-Jun-2006
processing started: 12/15/2007 19.55.24
Using default parameter: -p
The current device is: /dev/sdb3
Block size in bytes: 4096
Filesystem size in blocks: 58295868
**Phase 0 - Replay Journal Log
logredo failed (rc=-268). fsck continuing.
**Phase 1 - Check Blocks, Files/Directories, and Directory Entries
The root directory has an invalid data format. Will correct.
**Phase 2 - Count links
**Phase 3 - Duplicate Block Rescan and Directory Connectedness
**Phase 4 - Report Problems
**Phase 5 - Check Connectivity
**Phase 6 - Perform Approved Corrections
**Phase 7 - Rebuild File/Directory Allocation Maps
**Phase 8 - Rebuild Disk Allocation Maps
**Phase 9 - Reformat File System Log
233183472 kilobytes total disk space.
0 kilobytes in 1 directories.
0 kilobytes in 0 user files.
0 kilobytes in extended attributes
68888 kilobytes reserved for system use.
233114584 kilobytes are available for use.
Filesystem is clean.
</pre>

[David Kleikamp]

Logged In: YES
user_id=422440
Originator: NO

Ouch!

Usually, when the root directory is found to be bad, all if it's contents get dumped into the lost+found directory. It looks like nothing at all was found. And the journal wasn't found to be valid either (logredo failure). I'm not sure how to explain this one. Was this a recently created file system? This looks very odd.