First letter in mount path of bricks are getting truncated for every volume.

[Shwetha-Acharya]

Description of problem:
Volume Name: master
Type: Distributed-Replicate
Volume ID: d6c52eee-0121-4944-89b6-3630fe14dbc2
Status: Started
Snapshot Count: 0
Number of Bricks: 2 x 2 = 4
Transport-type: tcp
Bricks:
Brick1: vm1:/d/backends/master1
Brick2: vm1:/d/backends/master2
Brick3: vm1:/d/backends/master3
Brick4: vm1:/d/backends/master4
Options Reconfigured:
changelog.changelog: on
geo-replication.ignore-pid-check: on
geo-replication.indexing: on
storage.fips-mode-rchecksum: on
transport.address-family: inet
nfs.disable: on
performance.client-io-threads: off

[root@vm1 bricks]# grep -nR mount /var/lib/glusterd/vols/master/bricks/
/var/lib/glusterd/vols/master/bricks/vm1:-d-backends-master1:9:mount_dir=//backends/master1
/var/lib/glusterd/vols/master/bricks/vm1:-d-backends-master4:9:mount_dir=//backends/master4
/var/lib/glusterd/vols/master/bricks/vm1:-d-backends-master2:9:mount_dir=//backends/master2
/var/lib/glusterd/vols/master/bricks/vm1:-d-backends-master3:9:mount_dir=//backends/master3

[root@vm1 bricks]# ls //backends/master1
ls: cannot access '//backends/master1': No such file or directory
[root@vm1 bricks]#ls /d/backends/master1/.glusterfs/

Here letter d in /d/backends/master1/.glusterfs/ is getting truncated into //backends/master1

It is observed that first letter is getting truncated in mount path of brick inside /var/lib/glusterd/vols/master/bricks/vm1:-d-backends-master{1..4}: for all the instances of volume creation.

The exact command to reproduce the issue

1. create any gluster volume
   #gluster volume create vol-name ip:brick force

2. start the gluster volume
   #gluster volume start vol-name

3. mount the volume to a mount point
   #mount -t glusterfs ip:vol-name mount-point

4. grep for mount under /var/lib/glusterd/vols/vol_name/bricks/

The full output of the command that failed:
[root@vm1 bricks]# grep -nR mount /var/lib/glusterd/vols/ma/bricks/
/var/lib/glusterd/vols/ma/bricks/vm1:-e1:9:mount_dir=/1
/var/lib/glusterd/vols/ma/bricks/vm1:-e2:9:mount_dir=/2
/var/lib/glusterd/vols/ma/bricks/vm1:-e3:9:mount_dir=/3

Expected results:
[root@vm1 bricks]# grep -nR mount /var/lib/glusterd/vols/ma/bricks/
/var/lib/glusterd/vols/ma/bricks/vm1:-e1:9:mount_dir=/e1
/var/lib/glusterd/vols/ma/bricks/vm1:-e2:9:mount_dir=/e2
/var/lib/glusterd/vols/ma/bricks/vm1:-e3:9:mount_dir=/e3

- The output of the gluster volume info command:
Volume Name: ma
Type: Distribute
Volume ID: 7767732e-558d-4fd3-ad79-931615c51657
Status: Started
Snapshot Count: 0
Number of Bricks: 3
Transport-type: tcp
Bricks:
Brick1: vm1:/e1
Brick2: vm1:/e2
Brick3: vm1:/e3
Options Reconfigured:
storage.fips-mode-rchecksum: on
transport.address-family: inet
nfs.disable: on

[sanjurakonde]

@nik-redhat I could reproduce this issue every time. Please send out a fix.

[gluster-ant]

A patch https://review.gluster.org/24989 has been posted that references this issue.

glusterd: mount directory getting truncated on mounting shared_storage

Issue:
In case of a user created volume the mount point
is the brick path 'ex: /data/brick' but in case of
shared_storage the mount point is '/'.So, here
we increment the array by one so as to get the exact
path of brick without '/', which works fine for other
volumes as the pointer of the brick_dir variable is
at '/', but for shared_storage it is at 'v'(where v is
starting letter of 'var' directory). So, on incrementing
the path we get in case of shared_storage starts from
'ar/lib/glusterd/...'

Fix:
Only, increment the pointer if the current position is '/',
else the path will be wrong.

Fixes: #1480

Change-Id: Id31bb13f58134ae2099884fbc5984c4e055fb357
Signed-off-by: nik-redhat nladha@redhat.com