Bug 1232199

+++ This bug was initially created as a clone of Bug #1224611 +++

Description of problem:
commit c93c433 introduces signing of objects during write/truncate [first modification]. This avoids signing files which were never modified after creation.

But, bitrot daemon sapwns a filesystem crawler (one top-down scan of the filesystem) that triggers signing of files which may have got missed in the last run (due to disabling bitrot and other scenarios). Triggering signing does not take into account the file size and hence triggers signing for empty files.

Fix: The "oneshot" crawler needs to take into account the file size to counter this issue. Moreover, this check needs to be done *only* when an object has no bitrot extended attributed (version and signature). This check is required to handle truncates.

Although harmless, this situation can be avoided with some minor modifications.

Version-Release number of selected component (if applicable):
mainline

How reproducible:
always

Steps to Reproduce:
1. Create a Gluster volume and enable bitrot
2. create some empty files
3. before the files can be signed restart bitrot daemon

Actual results:
Empty files are signed

Expected results:
Since bitrot daemon signs files only on modification, empty files need not be signed.

Additional info:
None

--- Additional comment from Niels de Vos on 2015-06-02 04:20:20 EDT ---

The required changes to fix this bug have not made it into glusterfs-3.7.1. This bug is now getting tracked for glusterfs-3.7.2.

--- Additional comment from Anand Avati on 2015-06-02 08:54:35 EDT ---

REVIEW: http://review.gluster.org/10947 (features/bit-rot: check for both inmemory and ondisk staleness) posted (#2) for review on master by Raghavendra Bhat (raghavendra)

--- Additional comment from Anand Avati on 2015-06-12 06:45:24 EDT ---

REVIEW: http://review.gluster.org/10947 (features/bit-rot: check for both inmemory and ondisk staleness) posted (#3) for review on master by Venky Shankar (vshankar)

--- Additional comment from Anand Avati on 2015-06-15 00:47:06 EDT ---

REVIEW: http://review.gluster.org/10947 (features/bit-rot: check for both inmemory and ondisk staleness) posted (#4) for review on master by Venky Shankar (vshankar)

--- Additional comment from Anand Avati on 2015-06-15 05:41:49 EDT ---

REVIEW: http://review.gluster.org/10947 (features/bit-rot: check for both inmemory and ondisk staleness) posted (#5) for review on master by Raghavendra Bhat (raghavendra)

--- Additional comment from Anand Avati on 2015-06-15 23:07:24 EDT ---

COMMIT: http://review.gluster.org/10947 committed in master by Venky Shankar (vshankar) 
------
commit 60b6e5d2c3442ea0f7f85374d6613cd0dd76604c
Author: Raghavendra Bhat <raghavendra>
Date:   Wed May 27 17:00:36 2015 +0530

    features/bit-rot: check for both inmemory and ondisk staleness
    
    * Let bit-rot stub check both on disk ongoing version, signed version xattrs and
      the in memory flags in the inode and then decide whether the inode is stale or
      not. This information is used by one shot crawler in BitD to decide whether to
      trigger the sign for the object or skip it.
    
      NOTE: The above check should be done only for BitD. For scrubber its still the
            old way of comparing on disk ongoing version with signed version.
    
    * BitD's one shot crawler should not sign zero byte objects if they do not contain
      signature. (Means the object was just created and nothing was written to it).
    
    Change-Id: I6941aefc2981bf79a6aeb476e660f79908e165a8
    BUG: 1224611
    Signed-off-by: Raghavendra Bhat <raghavendra>
    Reviewed-on: http://review.gluster.org/10947
    Reviewed-by: Venky Shankar <vshankar>
    Tested-by: Venky Shankar <vshankar>
    Tested-by: Gluster Build System <jenkins.com>