linux-stable.git/drivers/md, branch v3.18.55

dm space map disk: fix some book keeping in the disk space map

2017-05-25T12:17:57+00:00

commit 0377a07c7a035e0d033cd8b29f0cb15244c0916a upstream.

When decrementing the reference count for a block, the free count wasn't
being updated if the reference count went to zero.

Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm thin metadata: call precommit before saving the roots

2017-05-25T12:17:57+00:00

commit 91bcdb92d39711d1adb40c26b653b7978d93eb98 upstream.

These calls were the wrong way round in __write_initial_superblock.

Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm bufio: avoid a possible ABBA deadlock

2017-05-25T12:17:57+00:00

commit 1b0fb5a5b2dc0dddcfa575060441a7176ba7ac37 upstream.

__get_memory_limit() tests if dm_bufio_cache_size changed and calls
__cache_size_refresh() if it did.  It takes dm_bufio_clients_lock while
it already holds the client lock.  However, lock ordering is violated
because in cleanup_old_buffers() dm_bufio_clients_lock is taken before
the client lock.

This results in a possible deadlock and lockdep engine warning.

Fix this deadlock by changing mutex_lock() to mutex_trylock().  If the
lock can't be taken, it will be re-checked next time when a new buffer
is allocated.

Also add "unlikely" to the if condition, so that the optimizer assumes
that the condition is false.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm btree: fix for dm_btree_find_lowest_key()

2017-05-25T12:17:56+00:00

commit 7d1fedb6e96a960aa91e4ff70714c3fb09195a5a upstream.

dm_btree_find_lowest_key() is giving incorrect results.  find_key()
traverses the btree correctly for finding the highest key, but there is
an error in the way it traverses the btree for retrieving the lowest
key.  dm_btree_find_lowest_key() fetches the first key of the rightmost
block of the btree instead of fetching the first key from the leftmost
block.

Fix this by conditionally passing the correct parameter to value64()
based on the @find_highest flag.

Signed-off-by: Erez Zadok 
Signed-off-by: Vinothkumar Raja 
Signed-off-by: Nidhi Panpalia 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

md/raid1: avoid reusing a resync bio after error handling.

2017-05-20T12:18:42+00:00

commit 0c9d5b127f695818c2c5a3868c1f28ca2969e905 upstream.

fix_sync_read_error() modifies a bio on a newly faulty
device by setting bi_end_io to end_sync_write.
This ensure that put_buf() will still call rdev_dec_pending()
as required, but makes sure that subsequent code in
fix_sync_read_error() doesn't try to read from the device.

Unfortunately this interacts badly with sync_request_write()
which assumes that any bio with bi_end_io set to non-NULL
other than end_sync_read is safe to write to.

As the device is now faulty it doesn't make sense to write.
As the bio was recently used for a read, it is "dirty"
and not suitable for immediate submission.
In particular, ->bi_next might be non-NULL, which will cause
generic_make_request() to complain.

Break this interaction by refusing to write to devices
which are marked as Faulty.

Reported-and-tested-by: Michael Wang 
Fixes: 2e52d449bcec ("md/raid1: add failfast handling for reads.")
Signed-off-by: NeilBrown 
Signed-off-by: Shaohua Li 
Signed-off-by: Greg Kroah-Hartman

dm era: save spacemap metadata root after the pre-commit

2017-05-20T12:18:41+00:00

commit 117aceb030307dcd431fdcff87ce988d3016c34a upstream.

When committing era metadata to disk, it doesn't always save the latest
spacemap metadata root in superblock. Due to this, metadata is getting
corrupted sometimes when reopening the device. The correct order of update
should be, pre-commit (shadows spacemap root), save the spacemap root
(newly shadowed block) to in-core superblock and then the final commit.

Signed-off-by: Somasundaram Krishnasamy 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm ioctl: prevent stack leak in dm ioctl call

2017-05-08T05:44:13+00:00

commit 4617f564c06117c7d1b611be49521a4430042287 upstream.

When calling a dm ioctl that doesn't process any data
(IOCTL_FLAGS_NO_PARAMS), the contents of the data field in struct
dm_ioctl are left initialized.  Current code is incorrectly extending
the size of data copied back to user, causing the contents of kernel
stack to be leaked to user.  Fix by only copying contents before data
and allow the functions processing the ioctl to override.

Signed-off-by: Adrian Salido 
Reviewed-by: Alasdair G Kergon 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

md:raid1: fix a dead loop when read from a WriteMostly disk

2017-05-08T05:44:07+00:00

commit 816b0acf3deb6d6be5d0519b286fdd4bafade905 upstream.

If first_bad == this_sector when we get the WriteMostly disk
in read_balance(), valid disk will be returned with zero
max_sectors. It'll lead to a dead loop in make_request(), and
OOM will happen because of endless allocation of struct bio.

Since we can't get data from this disk in this case, so
continue for another disk.

Signed-off-by: Wei Fang 
Signed-off-by: Shaohua Li 
Cc: Julia Lawall 
Signed-off-by: Greg Kroah-Hartman

dm bufio: hide bogus warning

2017-04-30T03:49:14+00:00

mips-gcc-5.3 warns about correct code on linux-3.18 and earlier:

In file included from ../include/linux/blkdev.h:4:0,
                 from ../drivers/md/dm-bufio.h:12,
                 from ../drivers/md/dm-bufio.c:9:
../drivers/md/dm-bufio.c: In function 'alloc_buffer':
../include/linux/sched.h:1975:56: warning: 'noio_flag' may be used uninitialized in this function [-Wmaybe-uninitialized]
  current->flags = (current->flags & ~PF_MEMALLOC_NOIO) | flags;
                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
../drivers/md/dm-bufio.c:325:11: note: 'noio_flag' was declared here

The warning disappeared on later kernels with this commit: be0c37c985ed
("MIPS: Rearrange PTE bits into fixed positions.")  I assume this only
happened because it changed some inlining decisions.

On 3.18.y, we can shut up the warning by adding an extra initialization.

Signed-off-by: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman

md/raid1/10: fix potential deadlock

2017-04-22T05:15:03+00:00

commit 61eb2b43b99ebdc9bc6bc83d9792257b243e7cb3 upstream.

Neil Brown pointed out a potential deadlock in raid 10 code with
bio_split/chain. The raid1 code could have the same issue, but recent
barrier rework makes it less likely to happen. The deadlock happens in
below sequence:

1. generic_make_request(bio), this will set current->bio_list
2. raid10_make_request will split bio to bio1 and bio2
3. __make_request(bio1), wait_barrer, add underlayer disk bio to
current->bio_list
4. __make_request(bio2), wait_barrer

If raise_barrier happens between 3 & 4, since wait_barrier runs at 3,
raise_barrier waits for IO completion from 3. And since raise_barrier
sets barrier, 4 waits for raise_barrier. But IO from 3 can't be
dispatched because raid10_make_request() doesn't finished yet.

The solution is to adjust the IO ordering. Quotes from Neil:
"
It is much safer to:

    if (need to split) {
        split = bio_split(bio, ...)
        bio_chain(...)
        make_request_fn(split);
        generic_make_request(bio);
   } else
        make_request_fn(mddev, bio);

This way we first process the initial section of the bio (in 'split')
which will queue some requests to the underlying devices.  These
requests will be queued in generic_make_request.
Then we queue the remainder of the bio, which will be added to the end
of the generic_make_request queue.
Then we return.
generic_make_request() will pop the lower-level device requests off the
queue and handle them first.  Then it will process the remainder
of the original bio once the first section has been fully processed.
"

Note, this only happens in read path. In write path, the bio is flushed to
underlaying disks either by blk flush (from schedule) or offladed to raid1/10d.
It's queued in current->bio_list.

Cc: Coly Li 
Suggested-by: NeilBrown 
Reviewed-by: Jack Wang 
Signed-off-by: Shaohua Li 
Signed-off-by: Greg Kroah-Hartman