Bug 1124583

Summary:	[SNAPSHOT] Snap mount doesn't inheret mount options from parent brick
Product:	[Red Hat Storage] Red Hat Gluster Storage	Reporter:	Dustin Black <dblack>
Component:	snapshot	Assignee:	Vijaikumar Mallikarjuna <vmallika>
Status:	CLOSED ERRATA	QA Contact:	Rahul Hinduja <rhinduja>
Severity:	high	Docs Contact:
Priority:	high
Version:	rhgs-3.0	CC:	asengupt, nsathyan, rhs-bugs, rjoseph, smohan, ssaha, ssamanta, storage-qa-internal, vmallika
Target Milestone:	---
Target Release:	RHGS 3.0.0
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	SNAPSHOT
Fixed In Version:	glusterfs-3.6.0.28-1	Doc Type:	Bug Fix
Doc Text:	Previously snapshot bricks are mounted with 'rw, nouuid' hard-coded mount options. Now we use the mount options used in the original brick.	Story Points:	---
Clone Of:
Clones:	1125180 (view as bug list)		Environment:
Last Closed:	2014-09-22 19:45:05 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:	1132058, 1132451, 1145090
Bug Blocks:	1125180, 1145088

Description Dustin Black 2014-07-29 20:51:58 UTC

Description of problem:
When creating a voulme snapshot with the 'gluster snapshot create <snapname> <volname(s)>" command, the underlying LV snap is automatically mounted under /var/run/gluster/snaps/<UUID>/brick<n>. However, this mount does not inherit the mount options for the original brick acting as the parent for the snap.

If the snap is restored, this could lead to performance degredations, functional limitations, or in extreme scenarios even potential data loss.


Version-Release number of selected component (if applicable):
# rpm -qa |grep -i glusterfs
glusterfs-fuse-3.6.0.22-1.el6rhs.x86_64
glusterfs-server-3.6.0.22-1.el6rhs.x86_64
glusterfs-libs-3.6.0.22-1.el6rhs.x86_64
glusterfs-cli-3.6.0.22-1.el6rhs.x86_64
samba-glusterfs-3.6.9-168.4.el6rhs.x86_64
glusterfs-api-3.6.0.22-1.el6rhs.x86_64
glusterfs-rdma-3.6.0.22-1.el6rhs.x86_64
glusterfs-3.6.0.22-1.el6rhs.x86_64
glusterfs-geo-replication-3.6.0.22-1.el6rhs.x86_64


How reproducible:
Consistently


Steps to Reproduce:
1. Create a volume snapshot with 'gluster snapshot create <snapname> <volname(s)>'
2. Compare the mount options of the parent brick and the snap in the output of the 'mount' command


Actual results:
Snapshot is mounted with only the 'rw' mount option.


Expected results:
Snapshot is mounted with the same mount options specified for the parent brick.


Additional info:
# gluster volume info
 
Volume Name: rep01
Type: Replicate
Volume ID: 4b7bf419-2681-46a7-a04f-cf57f81345be
Status: Started
Snap Volume: no
Number of Bricks: 1 x 2 = 2
Transport-type: tcp
Bricks:
Brick1: n1:/rhs/storage1/rep01
Brick2: n2:/rhs/storage1/rep01
Options Reconfigured:
features.barrier: disable
performance.readdir-ahead: on
snap-max-hard-limit: 256
snap-max-soft-limit: 90
auto-delete: disable
# grep datavg /etc/fstab
/dev/mapper/datavg-rhsdata /rhs/storage1 xfs inode64,noatime 1 2
# gluster snapshot create rep01-snap01 rep01
snapshot create: success: Snap rep01-snap01 created successfully
# lvs | grep datavg
  LV                                 VG     Attr       LSize   Pool        Origin  Data%  Move Log Cpy%Sync Convert
  e326a70445d34fd0b34e803837df38ce_0 datavg Vwi-aotz--   1.81g rhsthinpool rhsdata   1.68                          
  rhsdata                            datavg Vwi-aotz--   1.81g rhsthinpool           1.68                          
  rhsthinpool                        datavg twi-a-tz--   1.81g                       2.25                          
# mount | grep datavg
/dev/mapper/datavg-rhsdata on /rhs/storage1 type xfs (rw,noatime,inode64)
/dev/mapper/datavg-e326a70445d34fd0b34e803837df38ce_0 on /var/run/gluster/snaps/e326a70445d34fd0b34e803837df38ce/brick1 type xfs (rw)

Comment 2 Vijaikumar Mallikarjuna 2014-07-31 09:16:27 UTC

Patch http://review.gluster.org/#/c/8394 submitted upstream

Comment 4 Sayan Saha 2014-08-01 14:08:27 UTC

We should take it in but not delay build 26 for this one.

Comment 5 Avra Sengupta 2014-08-03 18:49:34 UTC

Fix at https://code.engineering.redhat.com/gerrit/30209

Comment 6 rjoseph 2014-08-20 11:29:39 UTC

note: Snapshot bricks are mounted with an additional option of (nouuid). Therefore even if the original brick does not have "nouuid" option the snap brick will have this option.

Comment 11 errata-xmlrpc 2014-09-22 19:45:05 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHEA-2014-1278.html