Enabling lazy counters damages filesystem
Marcin Mirosław
marcin at mejor.pl
Wed Apr 28 09:34:25 CDT 2010
Hello,
Please look at this:
# mkfs.xfs -f /dev/malowazne/test
meta-data=/dev/malowazne/test isize=256 agcount=4, agsize=524288 blks
= sectsz=512 attr=2
data = bsize=4096 blocks=2097152, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=0
realtime =none extsz=4096 blocks=0, rtextents=0
# xfs_check /dev/malowazne/test
# xfs_check /dev/malowazne/test
It's still clean.
# xfs_admin -c 1 /dev/malowazne/test
Enabling lazy-counters
# xfs_check /dev/malowazne/test
sb_features2 (0xa) not same as sb_bad_features2 (0x8)
Not good, let's repair fs:
# xfs_repair /dev/malowazne/test
Phase 1 - find and verify superblock...
superblock has a features2 mismatch, correcting
writing modified primary superblock
Phase 2 - using internal log
- zero log...
- scan filesystem freespace and inode maps...
- found root inode chunk
Phase 3 - for each AG...
- scan and clear agi unlinked lists...
- process known inodes and perform inode discovery...
- agno = 0
- agno = 1
- agno = 2
- agno = 3
- process newly discovered inodes...
Phase 4 - check for duplicate blocks...
- setting up duplicate extent list...
- check for inodes claiming duplicate blocks...
- agno = 0
- agno = 1
- agno = 2
- agno = 3
Phase 5 - rebuild AG headers and trees...
- reset superblock...
Phase 6 - check inode connectivity...
- resetting contents of realtime bitmap and summary inodes
- traversing filesystem ...
- traversal finished ...
- moving disconnected inodes to lost+found ...
Phase 7 - verify and correct link counts...
done
Now i'm trying to turn off lazy counters:
# xfs_admin -c 0 /dev/malowazne/test
Disabling lazy-counters
# xfs_check /dev/malowazne/test
sb_features2 (0x8) not same as sb_bad_features2 (0xa)
# xfs_repair /dev/malowazne/test
Phase 1 - find and verify superblock...
superblock has a features2 mismatch, correcting
writing modified primary superblock
Phase 2 - using internal log
- zero log...
- scan filesystem freespace and inode maps...
- found root inode chunk
Phase 3 - for each AG...
- scan and clear agi unlinked lists...
- process known inodes and perform inode discovery...
- agno = 0
- agno = 1
- agno = 2
- agno = 3
- process newly discovered inodes...
Phase 4 - check for duplicate blocks...
- setting up duplicate extent list...
- check for inodes claiming duplicate blocks...
- agno = 0
- agno = 1
- agno = 2
- agno = 3
Phase 5 - rebuild AG headers and trees...
- reset superblock...
Phase 6 - check inode connectivity...
- resetting contents of realtime bitmap and summary inodes
- traversing filesystem ...
- traversal finished ...
- moving disconnected inodes to lost+found ...
Phase 7 - verify and correct link counts...
done
# mount /dev/malowazne/test /mnt/test
# xfs_info /dev/malowazne/test
meta-data=/dev/mapper/malowazne-test isize=256 agcount=4,
agsize=524288 blks
= sectsz=512 attr=2
data = bsize=4096 blocks=2097152, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0
log =internal bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
So as you can see lazy conters are still turn on.
I'm using:
# mkfs.xfs -V
mkfs.xfs version 3.0.3
# uname -r
2.6.33-zen2
The same problem noticed with kernel-2.6.28-r9 with grsecurity, and with
xfsprogs-3.0.0 .
Is this behaviour bug or i don't know about something that i should?:)
Regards!
Marcin
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