linux-stable.git/drivers/block, branch v4.14.166

xen/blkback: Avoid unmapping unmapped grant pages

2020-01-09T09:17:59+00:00

[ Upstream commit f9bd84a8a845d82f9b5a081a7ae68c98a11d2e84 ]

For each I/O request, blkback first maps the foreign pages for the
request to its local pages.  If an allocation of a local page for the
mapping fails, it should unmap every mapping already made for the
request.

However, blkback's handling mechanism for the allocation failure does
not mark the remaining foreign pages as unmapped.  Therefore, the unmap
function merely tries to unmap every valid grant page for the request,
including the pages not mapped due to the allocation failure.  On a
system that fails the allocation frequently, this problem leads to
following kernel crash.

  [  372.012538] BUG: unable to handle kernel NULL pointer dereference at 0000000000000001
  [  372.012546] IP: [] gnttab_unmap_refs.part.7+0x1c/0x40
  [  372.012557] PGD 16f3e9067 PUD 16426e067 PMD 0
  [  372.012562] Oops: 0002 [#1] SMP
  [  372.012566] Modules linked in: act_police sch_ingress cls_u32
  ...
  [  372.012746] Call Trace:
  [  372.012752]  [] gnttab_unmap_refs+0x34/0x40
  [  372.012759]  [] xen_blkbk_unmap+0x83/0x150 [xen_blkback]
  ...
  [  372.012802]  [] dispatch_rw_block_io+0x970/0x980 [xen_blkback]
  ...
  Decompressing Linux... Parsing ELF... done.
  Booting the kernel.
  [    0.000000] Initializing cgroup subsys cpuset

This commit fixes this problem by marking the grant pages of the given
request that didn't mapped due to the allocation failure as invalid.

Fixes: c6cc142dac52 ("xen-blkback: use balloon pages for all mappings")

Reviewed-by: David Woodhouse 
Reviewed-by: Maximilian Heyne 
Reviewed-by: Paul Durrant 
Reviewed-by: Roger Pau Monné 
Signed-off-by: SeongJae Park 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

xen-blkback: prevent premature module unload

2020-01-09T09:17:53+00:00

[ Upstream commit fa2ac657f9783f0891b2935490afe9a7fd29d3fa ]

Objects allocated by xen_blkif_alloc come from the 'blkif_cache' kmem
cache. This cache is destoyed when xen-blkif is unloaded so it is
necessary to wait for the deferred free routine used for such objects to
complete. This necessity was missed in commit 14855954f636 "xen-blkback:
allow module to be cleanly unloaded". This patch fixes the problem by
taking/releasing extra module references in xen_blkif_alloc/free()
respectively.

Signed-off-by: Paul Durrant 
Reviewed-by: Roger Pau Monné 
Signed-off-by: Juergen Gross 
Signed-off-by: Sasha Levin

nbd: fix shutdown and recv work deadlock v2

2019-12-31T11:38:07+00:00

commit 1c05839aa973cfae8c3db964a21f9c0eef8fcc21 upstream.

This fixes a regression added with:

commit e9e006f5fcf2bab59149cb38a48a4817c1b538b4
Author: Mike Christie 
Date:   Sun Aug 4 14:10:06 2019 -0500

    nbd: fix max number of supported devs

where we can deadlock during device shutdown. The problem occurs if
the recv_work's nbd_config_put occurs after nbd_start_device_ioctl has
returned and the userspace app has droppped its reference via closing
the device and running nbd_release. The recv_work nbd_config_put call
would then drop the refcount to zero and try to destroy the config which
would try to do destroy_workqueue from the recv work.

This patch just has nbd_start_device_ioctl do a flush_workqueue when it
wakes so we know after the ioctl returns running works have exited. This
also fixes a possible race where we could try to reuse the device while
old recv_works are still running.

Cc: stable@vger.kernel.org
Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs")
Signed-off-by: Mike Christie 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

loop: fix no-unmap write-zeroes request behavior

2019-12-31T11:37:18+00:00

[ Upstream commit efcfec579f6139528c9e6925eca2bc4a36da65c6 ]

Currently, if the loop device receives a WRITE_ZEROES request, it asks
the underlying filesystem to punch out the range.  This behavior is
correct if unmapping is allowed.  However, a NOUNMAP request means that
the caller doesn't want us to free the storage backing the range, so
punching out the range is incorrect behavior.

To satisfy a NOUNMAP | WRITE_ZEROES request, loop should ask the
underlying filesystem to FALLOC_FL_ZERO_RANGE, which is (according to
the fallocate documentation) required to ensure that the entire range is
backed by real storage, which suffices for our purposes.

Fixes: 19372e2769179dd ("loop: implement REQ_OP_WRITE_ZEROES")
Signed-off-by: Darrick J. Wong 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

drbd: Change drbd_request_detach_interruptible's return type to int

2019-12-17T19:39:55+00:00

[ Upstream commit 5816a0932b4fd74257b8cc5785bc8067186a8723 ]

Clang warns when an implicit conversion is done between enumerated
types:

drivers/block/drbd/drbd_state.c:708:8: warning: implicit conversion from
enumeration type 'enum drbd_ret_code' to different enumeration type
'enum drbd_state_rv' [-Wenum-conversion]
                rv = ERR_INTR;
                   ~ ^~~~~~~~

drbd_request_detach_interruptible's only call site is in the return
statement of adm_detach, which returns an int. Change the return type of
drbd_request_detach_interruptible to match, silencing Clang's warning.

Reported-by: Nick Desaulniers 
Reviewed-by: Nick Desaulniers 
Signed-off-by: Nathan Chancellor 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

rsxx: add missed destroy_workqueue calls in remove

2019-12-17T19:37:30+00:00

[ Upstream commit dcb77e4b274b8f13ac6482dfb09160cd2fae9a40 ]

The driver misses calling destroy_workqueue in remove like what is done
when probe fails.
Add the missed calls to fix it.

Signed-off-by: Chuhong Yuan 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

drbd: fix print_st_err()'s prototype to match the definition

2019-12-05T14:37:45+00:00

[ Upstream commit 2c38f035117331eb78d0504843c79ea7c7fabf37 ]

print_st_err() is defined with its 4th argument taking an
'enum drbd_state_rv' but its prototype use an int for it.

Fix this by using 'enum drbd_state_rv' in the prototype too.

Signed-off-by: Luc Van Oostenryck 
Signed-off-by: Roland Kammerer 
Signed-off-by: Lars Ellenberg 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

drbd: do not block when adjusting "disk-options" while IO is frozen

2019-12-05T14:37:45+00:00

[ Upstream commit f708bd08ecbdc23d03aaedf5b3311ebe44cfdb50 ]

"suspending" IO is overloaded.
It can mean "do not allow new requests" (obviously),
but it also may mean "must not complete pending IO",
for example while the fencing handlers do their arbitration.

When adjusting disk options, we suspend io (disallow new requests), then
wait for the activity-log to become unused (drain all IO completions),
and possibly replace it with a new activity log of different size.

If the other "suspend IO" aspect is active, pending IO completions won't
happen, and we would block forever (unkillable drbdsetup process).

Fix this by skipping the activity log adjustment if the "al-extents"
setting did not change. Also, in case it did change, fail early without
blocking if it looks like we would block forever.

Signed-off-by: Lars Ellenberg 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

drbd: reject attach of unsuitable uuids even if connected

2019-12-05T14:37:44+00:00

[ Upstream commit fe43ed97bba3b11521abd934b83ed93143470e4f ]

Multiple failure scenario:
a) all good
   Connected Primary/Secondary UpToDate/UpToDate
b) lose disk on Primary,
   Connected Primary/Secondary Diskless/UpToDate
c) continue to write to the device,
   changes only make it to the Secondary storage.
d) lose disk on Secondary,
   Connected Primary/Secondary Diskless/Diskless
e) now try to re-attach on Primary

This would have succeeded before, even though that is clearly the
wrong data set to attach to (missing the modifications from c).
Because we only compared our "effective" and the "to-be-attached"
data generation uuid tags if (device->state.conn < C_CONNECTED).

Fix: change that constraint to (device->state.pdsk != D_UP_TO_DATE)
compare the uuids, and reject the attach.

This patch also tries to improve the reverse scenario:
first lose Secondary, then Primary disk,
then try to attach the disk on Secondary.

Before this patch, the attach on the Secondary succeeds, but since commit
drbd: disconnect, if the wrong UUIDs are attached on a connected peer
the Primary will notice unsuitable data, and drop the connection hard.

Though unfortunately at a point in time during the handshake where
we cannot easily abort the attach on the peer without more
refactoring of the handshake.

We now reject any attach to "unsuitable" uuids,
as long as we can see a Primary role,
unless we already have access to "good" data.

Signed-off-by: Lars Ellenberg 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

drbd: ignore "all zero" peer volume sizes in handshake

2019-12-05T14:37:44+00:00

[ Upstream commit 94c43a13b8d6e3e0dd77b3536b5e04a84936b762 ]

During handshake, if we are diskless ourselves, we used to accept any size
presented by the peer.

Which could be zero if that peer was just brought up and connected
to us without having a disk attached first, in which case both
peers would just "flip" their volume sizes.

Now, even a diskless node will ignore "zero" sizes
presented by a diskless peer.

Also a currently Diskless Primary will refuse to shrink during handshake:
it may be frozen, and waiting for a "suitable" local disk or peer to
re-appear (on-no-data-accessible suspend-io). If the peer is smaller
than what we used to be, it is not suitable.

The logic for a diskless node during handshake is now supposed to be:
believe the peer, if
 - I don't have a current size myself
 - we agree on the size anyways
 - I do have a current size, am Secondary, and he has the only disk
 - I do have a current size, am Primary, and he has the only disk,
   which is larger than my current size

Signed-off-by: Lars Ellenberg 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin