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Bug 1602236

Summary:	When reserve limits are reached, append on an existing file after truncate operation results to hang
Product:	[Community] GlusterFS	Reporter:	Ravishankar N <ravishankar>
Component:	replicate	Assignee:	Ravishankar N <ravishankar>
Status:	CLOSED CURRENTRELEASE	QA Contact:
Severity:	medium	Docs Contact:
Priority:	unspecified
Version:	mainline	CC:	bugs, moagrawa, pasik, pkarampu, ravishankar
Target Milestone:	---	Keywords:	Triaged
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	glusterfs-5.0	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:	1599998
Clones:	1603056 (view as bug list)		Environment:
Last Closed:	2018-10-23 15:14:52 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1599998, 1602241
Bug Blocks:	1603056

Description Ravishankar N 2018-07-18 03:54:08 UTC

+++ This bug was initially created as a clone of Bug #1599998 +++

Description of problem:
=======================
When reserve limits are reached, append on an existing file after truncate operation results to hang.

Version-Release number of selected component (if applicable):
3.12.2-13.el7rhgs.x86_64

How reproducible:
always

Steps to Reproduce:
===================
1) Create a Distributed-Replicate volume and start it.
2) Set the storage.reserve limits to 50 using below command,
 gluster v set distrep storage.reserve 50
3) FUSE mount the volume on a client.
4) Write data till the limits reaches reserve limits(you will see 100% mount point fill in df -h client output). I have used fallocate to quickly fill the disk.
5) Pick an existing file and truncate that file.
truncate -s 0 fallocate_99
It will throw ENOSPC error.
6) Now on the same file try to append some data.
cat /etc/redhat-release > fallocate_99

Actual results:
===============
append will hang. cat command hung here.

Expected results:
=================
No hungs.

Comment 1 Worker Ant 2018-07-18 03:57:10 UTC

REVIEW: https://review.gluster.org/20527 (afr: switch lk_owner only when pre-op succeeds) posted (#1) for review on master by Ravishankar N

Comment 2 Worker Ant 2018-07-18 16:50:31 UTC

COMMIT: https://review.gluster.org/20527 committed in master by "Ravishankar N" <ravishankar> with a commit message- afr: switch lk_owner only when pre-op succeeds

Problem:
In a disk full scenario, we take a failure path in afr_transaction_perform_fop()
and go to unlock phase. But we change the lk-owner before that, causing unlock
to fail. When mount issues another fop that takes locks on that file, it hangs.

Fix:
Change lk-owner only when we are about to perform the fop phase.
Also fix the same issue for arbiters when afr_txn_arbitrate_fop() fails the fop.

Also removed the DISK_SPACE_CHECK_AND_GOTO in posix_xattrop. Otherwise truncate
to zero will fail pre-op phase with ENOSPC when the user is actually trying to
freee up space.

Change-Id: Ic4c8a596b4cdf4a7fc189bf00b561113cf114353
fixes: bz#1602236
Signed-off-by: Ravishankar N <ravishankar>

Comment 3 Shyamsundar 2018-10-23 15:14:52 UTC

This bug is getting closed because a release has been made available that should address the reported issue. In case the problem is still not fixed with glusterfs-5.0, please open a new bug report.

glusterfs-5.0 has been announced on the Gluster mailinglists [1], packages for several distributions should become available in the near future. Keep an eye on the Gluster Users mailinglist [2] and the update infrastructure for your distribution.

[1] https://lists.gluster.org/pipermail/announce/2018-October/000115.html
[2] https://www.gluster.org/pipermail/gluster-users/