Marcio Barbosa 45a69b6113 volser: take RO volume offline during convertROtoRW
The vos convertROtoRW command converts a RO volume into a RW volume.
Unfortunately, the RO volume is not checked out from the fileserver
during this process. As a result, accesses to the volume being converted
can leave volume objects in an inconsistent state.

Moreover, consider the following scenario:

1. Create a volume on host_b and add replicas on host_a and host_b.

$ vos create host_b a vol_1
$ vos addsite host_b a vol_1
$ vos addiste host_a a vol_1

2. Mount the volume:

$ fs mkmount /afs/.mycell/vol_1 vol_1
$ vos release vol_1
$ vos release root.cell

3. Shutdown dafs on host_b:

$ bos shutdown host_b dafs

4. Remove RO reference to host_b from the vldb:

$ vos remsite host_b a vol_1

5. Attach the RO copy by touching it:

$ fs flushall
$ ls /afs/mycell/vol_1

6. Convert RO copy to RW:

$ vos convertROtoRW host_a a vol_1

Notice that FSYNC_com_VolDone fails silently (FSYNC_BAD_STATE), leaving
the volume object for the RO copy set as VOL_STATE_ATTACHED (on success,
this volume should be set as VOL_STATE_DELETED).

7. Add replica on host_a:

$ vos addsite host_a a vol_1

8. Wait until the "inUse" flag of the RO entry is cleared (or force this
to happen by attaching multiple volumes).

9. Release the volume:

$ vos release vol_1

Failed to start transaction on volume 536870922
Volume not attached, does not exist, or not on line
Error in vos release command.
Volume not attached, does not exist, or not on line

Notice that this happens because we cannot mark an attached volume as
destroyed (FSYNC_com_VolDone).

To avoid the problem mentioned above and to prevent accesses to the
volume being converted, take the RO volume offline before converting it
to RW.

Change-Id: Ifd342e1f420dc42e5da49242a7aa70db7d97a884
Reviewed-on: https://gerrit.openafs.org/14340
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
2020-11-13 12:33:46 -05:00
2018-02-04 15:34:55 -05:00
2016-09-25 21:05:23 -04:00
2020-09-19 02:00:24 -04:00
2020-10-08 00:13:06 -04:00
2020-10-08 00:13:06 -04:00
2020-09-18 11:23:28 -04:00
2015-12-28 19:32:17 -05:00

AFS is a distributed file system that enables users to share and
access all of the files stored in a network of computers as easily as
they access the files stored on their local machines. The file system is
called distributed for this exact reason: files can reside on many
different machines, but are available to users on every machine.

OpenAFS 1.0 was originally released by IBM under the terms of the
IBM Public License 1.0 (IPL10).  For details on IPL10 see the LICENSE
file in this directory.  The current OpenAFS distribution is licensed
under a combination of the IPL10 and many other licenses as granted by
the relevant copyright holders.  The LICENSE file in this directory
contains more details, thought it is not a comprehensive statement.

See INSTALL for information about building and installing OpenAFS
on various platforms.

See CODING for developer information and guidelines.

See NEWS for recent changes to OpenAFS.

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