To avoid deadlock when suspending a multipath device after all its paths have
failed, stop queueing any I/O that is about to fail *before* calling
freeze_bdev instead of after.

Instead of setting a multipath 'suspended' flag which would have to be reset
if an error occurs during the process, save the previous queueing state and
leave userspace to restore if it wishes.
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The multipath destructor must flush its workqueue.  Otherwise items that
reference the destroyed object could remain.

From: "goggin, edward" <egoggin@emc.com>
Signed-off-by: NLars Marowsky-Bree <lmb@suse.de>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

dm multipath will report barriers as not supported with this patch.
Signed-off-by: NLars Marowsky-Bree <lmb@suse.de>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

READA errors failing with EWOULDBLOCK/EAGAIN do not constitute a valid
reason for failing the path; this lead to erratic errors on DM multipath
devices.  This error can be safely propagated upwards without failing the
path.
Acked-by: NKevin Corry <kevcorry@us.ibm.com>
Acked-by: NJens Axboe <axboe@suse.de>
Signed-off-by: NLars Marowsky-Bree <lmb@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

dm-mpath.c needs to use a private workqueue (like other dm targets already do)
to avoid interfering with users of the default workqueue.
Signed-Off-By: NAlasdair G Kergon <agk@redhat.com>
Acked-by: NJens Axboe <axboe@suse.de>
Signed-off-by: NLars Marowsky-Bree <lmb@suse.de>
Signed-off-by: <mikenc@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!