Bug 1079067

Description of problem:
This is one of the left over issues from bug 970798. Bug 970798 basically says the only way to properly restore a corrupted meta device is an inactive swap to a new device. However lvm will still let you attempt to dump from a live device to a file and then attempt to restore from that dumped file. This doesn't work. If it's not supported then it shouldn't be allowed and if it is supported then if should be fixed.


SCENARIO - [verify_io_between_online_mda_corruptions]
Create a snapshot and then verify it's io contents in between ONLINE pool mda corruptions and restorations
Making origin volume
lvcreate --thinpool POOL --zero n -L 5G snapper_thinp
Sanity checking pool device metadata
(thin_check /dev/mapper/snapper_thinp-POOL_tmeta)
examining superblock
examining devices tree
examining mapping tree
lvcreate --virtualsize 1G -T snapper_thinp/POOL -n origin
lvcreate --virtualsize 1G -T snapper_thinp/POOL -n other1
lvcreate -V 1G -T snapper_thinp/POOL -n other2
lvcreate -V 1G -T snapper_thinp/POOL -n other3
lvcreate --virtualsize 1G -T snapper_thinp/POOL -n other4
lvcreate -V 1G -T snapper_thinp/POOL -n other5
Placing an XFS filesystem on origin volume
Mounting origin volume

Writing files to /mnt/origin
Checking files on /mnt/origin

*** Pool MDA Corrupt/Restore iteration 1/5 ***
syncing before snap creation...
Creating thin snapshot of origin volume
lvcreate -K -s /dev/snapper_thinp/origin -n snap1
Mounting thin snapshot volume
mkdir -p /mnt/snap1
mount -o nouuid /dev/snapper_thinp/snap1 /mnt/snap1

Checking files on /mnt/snap1
Writing files to /mnt/origin
Checking files on /mnt/origin

Dumping current pool metadata to /tmp/snapper_thinp_dump_1.8910.2296
thin_dump /dev/mapper/snapper_thinp-POOL_tmeta > /tmp/snapper_thinp_dump_1.8910.2296

Corrupting pool meta device (/dev/mapper/snapper_thinp-POOL_tmeta)
dd if=/dev/zero of=/dev/mapper/snapper_thinp-POOL_tmeta count=1
1+0 records in
1+0 records out
512 bytes (512 B) copied, 0.000413308 s, 1.2 MB/s
Verifying that pool meta device is now corrupt
thin_check /dev/mapper/snapper_thinp-POOL_tmeta
examining superblock
  superblock is corrupt
    bad checksum in superblock

Restoring /dev/mapper/snapper_thinp-POOL_tmeta using dumped file
thin_restore -i /tmp/snapper_thinp_dump_1.8910.2296 -o /dev/mapper/snapper_thinp-POOL_tmeta
Verifying that pool meta device is no longer corrupt
thin_check /dev/mapper/snapper_thinp-POOL_tmeta
examining superblock
examining devices tree
examining mapping tree

*** Pool MDA Corrupt/Restore iteration 2/5 ***
syncing before snap creation...
Creating thin snapshot of origin volume
lvcreate -K -s /dev/snapper_thinp/origin -n snap2
Mounting thin snapshot volume
mkdir -p /mnt/snap2
mount -o nouuid /dev/snapper_thinp/snap2 /mnt/snap2

Checking files on /mnt/snap2
Writing files to /mnt/origin
Checking files on /mnt/origin

Dumping current pool metadata to /tmp/snapper_thinp_dump_2.7659.2296
thin_dump /dev/mapper/snapper_thinp-POOL_tmeta > /tmp/snapper_thinp_dump_2.7659.2296
metadata contains errors (run thin_check for details).
perhaps you wanted to run with --repair
dump of current pool meta data failed

[root@harding-02 ~]# thin_check /dev/mapper/snapper_thinp-POOL_tmeta
examining superblock
examining devices tree
examining mapping tree
  thin device 1 is missing mappings [16384, -]
    too few entries in btree_node: 1, expected at least 84(max_entries = 252)too few entries in btree_node: 1, expected at least 84(max_entries = 252)too few entries in btree_node: 1, expected at least 84(max_entries = 252)too few entries in btree_node: 1, expected at least 84(max_entries = 252)too few entries in btree_node: 1, expected at least 84(max_entries = 252)too few entries in btree_node: 24, expected at least 84(max_entries = 252)parent key mismatch: parent was 1764, but lowest in node was 0parent key mismatch: parent was 1890, but lowest in node was 126the last key of the previous leaf was 16383 and the first key of this leaf is 2016the last key of the previous leaf was 16383 and the first key of this leaf is 2142the last key of the previous leaf was 16383 and the first key of this leaf is 2268the last key of the previous leaf was 16383 and the first key of this leaf is 2396the last key of the previous leaf was 16383 and the first key of this leaf is 2522the last key of the previous leaf was 16383 and the first key of this leaf is 2648the last key of the previous 


[root@harding-02 ~]# umount /mnt/*

[root@harding-02 ~]# vgchange -an snapper_thinp
  WARNING: Integrity check of metadata for thin pool snapper_thinp/POOL failed.
  0 logical volume(s) in volume group "snapper_thinp" now active

[root@harding-02 ~]# lvremove snapper_thinp
Removing pool "POOL" will remove 8 dependent volume(s). Proceed? [y/n]: y
  Check of thin pool snapper_thinp/POOL failed (status:1). Manual repair required (thin_dump --repair /dev/mapper/snapper_thinp-POOL_tmeta)!
  Failed to update thin pool POOL.
  Failed to update thin pool POOL.
  Failed to update thin pool POOL.
  Failed to update thin pool POOL.
  Failed to update thin pool POOL.
  Failed to update thin pool POOL.
  Failed to update thin pool POOL.
  Failed to update thin pool POOL.


Version-Release number of selected component (if applicable):
3.10.0-110.el7.x86_64
lvm2-2.02.105-13.el7    BUILT: Wed Mar 19 05:38:19 CDT 2014
lvm2-libs-2.02.105-13.el7    BUILT: Wed Mar 19 05:38:19 CDT 2014
lvm2-cluster-2.02.105-13.el7    BUILT: Wed Mar 19 05:38:19 CDT 2014
device-mapper-1.02.84-13.el7    BUILT: Wed Mar 19 05:38:19 CDT 2014
device-mapper-libs-1.02.84-13.el7    BUILT: Wed Mar 19 05:38:19 CDT 2014
device-mapper-event-1.02.84-13.el7    BUILT: Wed Mar 19 05:38:19 CDT 2014
device-mapper-event-libs-1.02.84-13.el7    BUILT: Wed Mar 19 05:38:19 CDT 2014
device-mapper-persistent-data-0.2.8-4.el7    BUILT: Fri Jan 24 14:28:55 CST 2014
cmirror-2.02.105-13.el7    BUILT: Wed Mar 19 05:38:19 CDT 2014