Re: inconsistent mount attributes (ro/rw), RHEL5 / Netapp

["Gregory Baker" <gregory.baker@amd.com>]

Ignore this email; my foolish use of

[root@adcgar04 tmp]# mount -v | grep pandora
[root@adcgar04 tmp]# cat /proc/mounts | grep pandora

and

[root@adcgar04 tmp]# umount -a -t nfs

make the captured session useless in debugging (as I cannot reproduce 
the behavior).

Sorry everyone!

--Greg


Gregory Baker wrote:
> 
> Gregory Baker wrote:
> 
>> So the deal is, the mount flags (and NFS options) are set only the first 
>> time that a given combination of server and filesystem are mounted. If 
>> you ever mount the same filesystem from the same server on another 
>> mountpoint, you'll get the flags and options that were passed on to the 
>> first mount. There's no working around that.
>> *****
> 
> Should these mount flags (and NFS options) expire/be removed from some 
> table somewhere when you unmount/remount the filesystem?  The mount 
> flags (and NFS options) persist between complete unmounting / remounting 
> of said filesystem.
> 
> [greg@apathy 115656]$ cat typescript
> 
> * Look at me.  Don't have anything mounted via NFS yet the mount
> * gets stuck as ro when mounted...
> 
> [root@adcgar04 tmp]# umount -a -t nfs
> [root@adcgar04 tmp]# mount -v | grep pandora
> [root@adcgar04 tmp]# cat /proc/mounts | grep pandora
> [root@adcgar04 tmp]# mount eng:/vol/vol4/pandora/pandora-k26_g25_64-2 /mnt2
> [root@adcgar04 tmp]# mount -v | grep pandora
> eng:/vol/vol4/pandora/pandora-k26_g25_64-2 on /mnt2 type nfs 
> (rw,addr=163.181.34.137)
> [root@adcgar04 tmp]# cat /proc/mounts | grep pandora
> eng:/vol/vol4/pandora/pandora-k26_g25_64-2 /mnt2 nfs 
> ro,vers=3,rsize=65536,wsize=65536,hard,intr,proto=tcp,timeo=600,retrans=2,sec=sys,addr=eng 
> 0 0
> [root@adcgar04 tmp]# touch /mnt2/asdf
> touch: cannot touch `/mnt2/asdf': Read-only file system
> 
> * OK, let's try this fancy mount command..
> 
> [root@adcgar04 tmp]# mount -o remount,rw /mnt2
> [root@adcgar04 tmp]#  mount -v | grep pandora
> eng:/vol/vol4/pandora/pandora-k26_g25_64-2 on /mnt2 type nfs 
> (rw,remount,addr=163.181.34.137)
> [root@adcgar04 tmp]#  cat /proc/mounts | grep pandora
> eng:/vol/vol4/pandora/pandora-k26_g25_64-2 /mnt2 nfs 
> rw,vers=3,rsize=65536,wsize=65536,hard,intr,proto=tcp,timeo=600,retrans=2,sec=sys,addr=eng 
> 0 0
> 
> * Everybody is happy!
> 
> [root@adcgar04 tmp]#  touch /mnt2/asdf
> 
> * Let's get rid of NFS mount and see what happens now
> 
> [root@adcgar04 tmp]# umount /mnt2
> [root@adcgar04 tmp]#  mount -v | grep pandora
> [root@adcgar04 tmp]#  cat /proc/mounts | grep pandora
> [root@adcgar04 tmp]#  mount eng:/vol/vol4/pandora/pandora-k26_g25_64-2 /mnt2
> [root@adcgar04 tmp]# mount -v | grep pandora
> eng:/vol/vol4/pandora/pandora-k26_g25_64-2 on /mnt2 type nfs 
> (rw,addr=163.181.34.137)
> [root@adcgar04 tmp]# cat /proc/mounts | grep pandora
> eng:/vol/vol4/pandora/pandora-k26_g25_64-2 /mnt2 nfs 
> rw,vers=3,rsize=65536,wsize=65536,hard,intr,proto=tcp,timeo=600,retrans=2,sec=sys,addr=eng 
> 0 0
> 
> * Everybody is happy!
> 
> [root@adcgar04 tmp]# touch /mnt2/asdf
> 
> * Let's give "something" the notion that this is a ro mount...
> 
> [root@adcgar04 tmp]# mount -o remount,ro /mnt2
> [root@adcgar04 tmp]#  mount -v | grep pandora
> eng:/vol/vol4/pandora/pandora-k26_g25_64-2 on /mnt2 type nfs 
> (ro,remount,addr=163.181.34.137)
> [root@adcgar04 tmp]#  cat /proc/mounts | grep pandora
> eng:/vol/vol4/pandora/pandora-k26_g25_64-2 /mnt2 nfs 
> ro,vers=3,rsize=65536,wsize=65536,hard,intr,proto=tcp,timeo=600,retrans=2,sec=sys,addr=eng 
> 0 0
> 
> * RO (expected)
> 
> [root@adcgar04 tmp]# touch /mnt2/asdf
> touch: cannot touch `/mnt2/asdf': Read-only file system
> 
> * OK, unmount NFS mount, try again
> 
> [root@adcgar04 tmp]#  umount /mnt2
> [root@adcgar04 tmp]#  mount -v | grep pandora
> [root@adcgar04 tmp]#  cat /proc/mounts | grep pandora
> [root@adcgar04 tmp]#  mount eng:/vol/vol4/pandora/pandora-k26_g25_64-2 /mnt2
> [root@adcgar04 tmp]#  mount -v | grep pandora
> eng:/vol/vol4/pandora/pandora-k26_g25_64-2 on /mnt2 type nfs 
> (rw,addr=163.181.34.137)
> [root@adcgar04 tmp]#  cat /proc/mounts | grep pandora
> eng:/vol/vol4/pandora/pandora-k26_g25_64-2 /mnt2 nfs 
> ro,vers=3,rsize=65536,wsize=65536,hard,intr,proto=tcp,timeo=600,retrans=2,sec=sys,addr=eng 
> 0 0
> 
> * Boo-RO/RW (unexpected)
> 
> [root@adcgar04 tmp]#  touch /mnt2/asdf
> touch: cannot touch `/mnt2/asdf': Read-only file system
> [root@adcgar04 tmp]# exit
> 
> * So it seems that something remembers the last mount permissions, even
> * though mount -v and /proc/mount do not show a filesystem mounted.
> * The permissions persist to be associated with the exported filesystem.
> * What causes this?  Note: it's not the automounter process; this was
> * stopped during testing.
> 
> 

-- 
----------------------------------------------------------------------
Greg Baker                                         512-602-3287 (work)
gregory.baker@amd.com                              512-602-6970 (fax)
5204 E. Ben White Blvd MS 625                      512-555-1212 (info)
Austin, TX 78741




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