Hello,
I have a setup of a partition on a SSD with nilfs on it all running under
Centos 5.5 on a x86. With some heavy amount of writes to the nilfs partition
the power was accidentally cycled. On bootup the nilfs partition reported
the following errors:
NILFS warning: Checksum error in segment payload
NILFS: error searching super root
I worked around this by modifying the nilfs kernel code to remove the full
check in load_segment_summary (i.e. basically just check the segment summary
and I made it further towards recovery of my data). Now, I have encountered
this error:
NILFS warning: Checksum error in super root
NILFS: error loading super root.
I am not comfortable changing the code in nilfs_read_super_root_block
without feedback from this list. I am okay if I lose some of
the data at the end as long as I can recover most of the data. Some
questions I have are:
1. Why cannot mount allow one to mount from an earlier checkpoint on a
previous segment if the super_root for the latest is corrupted, or
am I missing something? Does anybody have a mount that does?
2. Is there any work on a fsck for nilfs? Even if it is very pre-release it
might help me to recover my data?
3. On a accidental power failure I considered nilfs to be the most robust
on a SSD - am I wrong in my appraisal.
Any help is much appreciated. Thanks.
Zahid
P.S.: nilfs-tune works well on the partition:
nilfs-tune 2.0.22
Filesystem volume name: /writable
Filesystem UUID: 0ba44621-5e7c-40ad-8087-b9493765e419
Filesystem magic number: 0x3434
Filesystem revision #: 2.0
Filesystem features: (none)
Filesystem state: invalid or mounted
Filesystem OS type: Linux
Block size: 4096
Filesystem created: Tue May 24 17:12:08 2011
Last mount time: Fri Jun 3 19:07:49 2011
Last write time: Fri Jun 3 19:08:35 2011
Mount count: 715
Maximum mount count: 50
Reserve blocks uid: 0 (user root)
Reserve blocks gid: 0 (group root)
First inode: 11
Inode size: 128
DAT entry size: 32
Checkpoint size: 192
Segment usage size: 16
Number of segments: 1316
Device size: 11046551040
First data block: 1
# of blocks per segment: 2048
Reserved segments %: 5
Last checkpoint #: 1893038
Last block address: 712887
Last sequence #: 200747
Free blocks count: 1939456
Commit interval: 0
# of blks to create seg: 0
CRC seed: 0x298bad54
CRC check sum: 0x5e92199d
CRC check data size: 0x00000118
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