[Drbd-dev] verbose log output from drbd kernel module

["Tobin C. Harding" <me@tobin.cc>]

Currently the drdb kernel module is a little bit verbose. While there
are numerous repeated log lines, a number of them are repeated in
different sequences. It is not immediately clear which lines
are _really_ necessary to understand what is going on. A good
understanding of drdb is probably required to reduce the duplicates
without loss of information. There are however a number of duplicate log
entries that appear consecutively, these could be reduced to a
single instance without loss of information (assuming the number of
times the error message appears consecutively is not useful
information).

So far I have found the following duplicate consecutive log entries

#

[ 1274.952627] F2FS-fs (drbd0): Magic Mismatch, valid(0xf2f52010) - read(0x29363930)
[ 1274.952646] F2FS-fs (drbd0): Can't find valid F2FS filesystem in 1th superblock
[ 1274.953695] F2FS-fs (drbd0): Magic Mismatch, valid(0xf2f52010) - read(0x0)
[ 1274.953710] F2FS-fs (drbd0): Can't find valid F2FS filesystem in 2th superblock
[ 1274.953760] F2FS-fs (drbd0): Magic Mismatch, valid(0xf2f52010) - read(0x29363930)
[ 1274.953770] F2FS-fs (drbd0): Can't find valid F2FS filesystem in 1th superblock
[ 1274.953779] F2FS-fs (drbd0): Magic Mismatch, valid(0xf2f52010) - read(0x0)
[ 1274.953786] F2FS-fs (drbd0): Can't find valid F2FS filesystem in 2th superblock

# After adding/deploying a resource 

[1368149.470125] drbd backups: Preparing cluster-wide state change 3280213538 (1->-1 3/1)
[1368149.470127] drbd backups: Committing cluster-wide state change 3280213538 (0ms)
[1368149.470136] drbd backups: role( Secondary -> Primary )
[1368149.474569] drbd backups: role( Primary -> Secondary )
[1368149.479674] drbd backups: Preparing cluster-wide state change 1520483517 (1->-1 3/1)
[1368149.479676] drbd backups: Committing cluster-wide state change 1520483517 (0ms)
[1368149.479685] drbd backups: role( Secondary -> Primary )
[1368149.484642] drbd backups: role( Primary -> Secondary )
[1368164.080148] drbd backups: Preparing cluster-wide state change 3014496965 (1->-1 3/1)
[1368164.080150] drbd backups: Committing cluster-wide state change 3014496965 (0ms)
[1368164.080161] drbd backups: role( Secondary -> Primary )
... [repeats many times]

# If block device is busy

[1369106.294749] drbd backups: Failed: role( Primary -> Secondary )
[1369106.297290] drbd backups: State change failed: Device is held open by someone
... [repeats 6 times]


Would it be useful to reduce these log lines to a single instance?

thanks,
Tobin.