Bug 764201 (GLUSTER-2469)

Summary:	glusterd can render directories inaccessible
Product:	[Community] GlusterFS	Reporter:	tcp
Component:	glusterd	Assignee:	Kaushal <kaushal>
Status:	CLOSED CURRENTRELEASE	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	mainline	CC:	amarts, gluster-bugs, rabhat, sac
Target Milestone:	---	Keywords:	Reopened
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	glusterfs-3.4.0	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2013-07-24 17:31:42 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:	master	Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	817967

Description tcp 2011-02-28 07:28:36 UTC

I was trying to figure out how glusterd starts. Since it is the same binary as glusterfsd, it calls create_fuse_mount(). This quickly returns 0 if no mount point was specified, but if you did specify a mount point, it ends up making that directory a fuse mount. Any command on that directory hangs (for obvious reasons).

Now, I got a bit adventurous and ran glusterd as below:

# glusterd /var

and lo, every command after that hung up. The window manager wouldn't do many useful things. I had a root shell handy, but reboot wouldn't proceed. I had to forcefully power down the system to get out of this scenario. Bad!

We need to be careful about when to call create_fuse_mount(). We've got to be more defensive than depend on (the absence of) a variable to determine whether to call it or not.

Comment 1 Amar Tumballi 2011-07-15 06:03:29 UTC

'mount' should happen only when 'glusterfs' option is given. If not the last argument should not be treated as mountpoint.

Comment 2 Kaushal 2011-07-18 04:36:32 UTC

This patch should fix the problem
http://patches.gluster.com/patch/7961/

Comment 3 Amar Tumballi 2011-07-18 04:48:50 UTC

A bug gets resolved only after the patch is committed to the source repository. Keep it open till it gets committed.

Comment 4 Anand Avati 2011-07-21 10:38:44 UTC

CHANGE: http://review.gluster.com/5 (create_fuse_mount() now checks if it is a client process before performing) merged in master by Anand Avati (avati)

Comment 5 Raghavendra Bhat 2011-08-22 05:15:45 UTC

Tested with the mainline. gave glusterfsd <mount_point>, and did df -h, there was no hang and no message saying transport endpoint not connected. Tried with glusterd <mount point> and got the same results. 

Tried with glusterfs <mount point> and when I did df it said transport endpoint not connected (which is the expected result).

Comment 6 Sachidananda Urs 2011-10-09 03:05:54 UTC

Few suggestions:

glusterfsd.c:main
* Instead of calling create_fuse_mount and making checks on process_mode, call create_fuse_mount only if process_mode is client process.

glusterfsd.c:create_fuse_mount
* If mount point is not present, don't log it as a TRACE log, user has to know why mount failed.