[Bugs] [Bug 1186657] Inode infinite loop leads to glusterfsd segfault

[bugzilla at redhat.com]

https://bugzilla.redhat.com/show_bug.cgi?id=1186657

Amit Chaurasia <achauras at redhat.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ON_QA                       |VERIFIED



--- Comment #4 from Amit Chaurasia <achauras at redhat.com> ---
The issue was that a dentry in the inode table was skewed in a way that the
dentry of a file occured before its parent. So, the entry was like parent >
child > parent.

This triggered an infinite loop in inode table causing the loc>Path to be NULL
and as there was no way to handle this NULL path, a crash dump was triggered. 

This dentry issue in the inode table was caused by a race in readdirp.

I followed simple steps as suggested :

1. Create a 3 level folder structure.
/fuse_mnt1/test_1186657/bug1/sub_dir

2. cd to the folder and start creating and deleting the files.

while true; do touch a; rm -f a; done

3. From the other mount point, start a lookup:
while true; do ls -lR > /dev/null; done

4. I started this file and link creation from multiple terminals for different
files on different mount points. 

The idea was to try and create a race in readdirp while entries are being made
and deleted from the inode table.

Didn't see the crash neither the error messages in the logs files.

Note: I could see following quota messages on the log files:
==> /var/log/glusterfs/bricks/rhs-brick1-gv0.log <==
[2015-03-10 15:22:47.771144] W [quota.c:1773:quota_unlink_cbk] 0-gv0-quota:
quota context not set in inode (gfid:51a0154d-318c-42dc-9d31-12e3eaa13d15)

==> /var/log/glusterfs/bricks/rhs-brick3-gv0.log <==
[2015-03-10 15:22:47.774715] W [quota.c:1773:quota_unlink_cbk] 0-gv0-quota:
quota context not set in inode (gfid:51a0154d-318c-42dc-9d31-12e3eaa13d15)


Marking the bug verified.

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