Commit Graph

370 Commits

Author SHA1 Message Date
Linus Torvalds 53ef7d0e20 Merge tag 'libnvdimm-for-4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm updates from Dan Williams:
 "The bulk of this has been in multiple -next releases. There were a few
  late breaking fixes and small features that got added in the last
  couple days, but the whole set has received a build success
  notification from the kbuild robot.

  Change summary:

   - Region media error reporting: A libnvdimm region device is the
     parent to one or more namespaces. To date, media errors have been
     reported via the "badblocks" attribute attached to pmem block
     devices for namespaces in "raw" or "memory" mode. Given that
     namespaces can be in "device-dax" or "btt-sector" mode this new
     interface reports media errors generically, i.e. independent of
     namespace modes or state.

     This subsequently allows userspace tooling to craft "ACPI 6.1
     Section 9.20.7.6 Function Index 4 - Clear Uncorrectable Error"
     requests and submit them via the ioctl path for NVDIMM root bus
     devices.

   - Introduce 'struct dax_device' and 'struct dax_operations': Prompted
     by a request from Linus and feedback from Christoph this allows for
     dax capable drivers to publish their own custom dax operations.
     This fixes the broken assumption that all dax operations are
     related to a persistent memory device, and makes it easier for
     other architectures and platforms to add customized persistent
     memory support.

   - 'libnvdimm' core updates: A new "deep_flush" sysfs attribute is
     available for storage appliance applications to manually trigger
     memory controllers to drain write-pending buffers that would
     otherwise be flushed automatically by the platform ADR
     (asynchronous-DRAM-refresh) mechanism at a power loss event.
     Support for "locked" DIMMs is included to prevent namespaces from
     surfacing when the namespace label data area is locked. Finally,
     fixes for various reported deadlocks and crashes, also tagged for
     -stable.

   - ACPI / nfit driver updates: General updates of the nfit driver to
     add DSM command overrides, ACPI 6.1 health state flags support, DSM
     payload debug available by default, and various fixes.

  Acknowledgements that came after the branch was pushed:

   - commmit 565851c972 "device-dax: fix sysfs attribute deadlock":
     Tested-by: Yi Zhang <yizhan@redhat.com>

   - commit 23f4984483 "libnvdimm: rework region badblocks clearing"
     Tested-by: Toshi Kani <toshi.kani@hpe.com>"

* tag 'libnvdimm-for-4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (52 commits)
  libnvdimm, pfn: fix 'npfns' vs section alignment
  libnvdimm: handle locked label storage areas
  libnvdimm: convert NDD_ flags to use bitops, introduce NDD_LOCKED
  brd: fix uninitialized use of brd->dax_dev
  block, dax: use correct format string in bdev_dax_supported
  device-dax: fix sysfs attribute deadlock
  libnvdimm: restore "libnvdimm: band aid btt vs clear poison locking"
  libnvdimm: fix nvdimm_bus_lock() vs device_lock() ordering
  libnvdimm: rework region badblocks clearing
  acpi, nfit: kill ACPI_NFIT_DEBUG
  libnvdimm: fix clear length of nvdimm_forget_poison()
  libnvdimm, pmem: fix a NULL pointer BUG in nd_pmem_notify
  libnvdimm, region: sysfs trigger for nvdimm_flush()
  libnvdimm: fix phys_addr for nvdimm_clear_poison
  x86, dax, pmem: remove indirection around memcpy_from_pmem()
  block: remove block_device_operations ->direct_access()
  block, dax: convert bdev_dax_supported() to dax_direct_access()
  filesystem-dax: convert to dax_direct_access()
  Revert "block: use DAX for partition table reads"
  ext2, ext4, xfs: retrieve dax_device for iomap operations
  ...
2017-05-05 18:49:20 -07:00
Andrey Ryabinin a5f6a6a9c7 fs/block_dev: always invalidate cleancache in invalidate_bdev()
invalidate_bdev() calls cleancache_invalidate_inode() iff ->nrpages != 0
which doen't make any sense.

Make sure that invalidate_bdev() always calls cleancache_invalidate_inode()
regardless of mapping->nrpages value.

Fixes: c515e1fd36 ("mm/fs: add hooks to support cleancache")
Link: http://lkml.kernel.org/r/20170424164135.22350-3-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alexey Kuznetsov <kuznet@virtuozzo.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Nikolay Borisov <n.borisov.lkml@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03 15:52:12 -07:00
Arnd Bergmann 67fd389735 block, dax: use correct format string in bdev_dax_supported
The new message has an incorrect format string, causing a warning in some
configurations:

fs/block_dev.c: In function 'bdev_dax_supported':
fs/block_dev.c:779:5: error: format '%d' expects argument of type 'int', but argument 2 has type 'long int' [-Werror=format=]
     "error: dax access failed (%d)", len);

This changes it to use the correct %ld instead of %d.

Fixes: 2093f2e9df ("block, dax: convert bdev_dax_supported() to dax_direct_access()")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-05-01 13:16:29 -07:00
Dan Williams d4b29fd78e block: remove block_device_operations ->direct_access()
Now that all the producers and consumers of dax interfaces have been
converted to using dax_operations on a dax_device, remove the block
device direct_access enabling.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-04-25 13:20:46 -07:00
Dan Williams 2093f2e9df block, dax: convert bdev_dax_supported() to dax_direct_access()
Kill of the final user of bdev_direct_access() and struct blk_dax_ctl.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-04-25 13:20:46 -07:00
Ilya Dryomov 19b7ccf865 block: get rid of blk_integrity_revalidate()
Commit 25520d55cd ("block: Inline blk_integrity in struct gendisk")
introduced blk_integrity_revalidate(), which seems to assume ownership
of the stable pages flag and unilaterally clears it if no blk_integrity
profile is registered:

    if (bi->profile)
            disk->queue->backing_dev_info->capabilities |=
                    BDI_CAP_STABLE_WRITES;
    else
            disk->queue->backing_dev_info->capabilities &=
                    ~BDI_CAP_STABLE_WRITES;

It's called from revalidate_disk() and rescan_partitions(), making it
impossible to enable stable pages for drivers that support partitions
and don't use blk_integrity: while the call in revalidate_disk() can be
trivially worked around (see zram, which doesn't support partitions and
hence gets away with zram_revalidate_disk()), rescan_partitions() can
be triggered from userspace at any time.  This breaks rbd, where the
ceph messenger is responsible for generating/verifying CRCs.

Since blk_integrity_{un,}register() "must" be used for (un)registering
the integrity profile with the block layer, move BDI_CAP_STABLE_WRITES
setting there.  This way drivers that call blk_integrity_register() and
use integrity infrastructure won't interfere with drivers that don't
but still want stable pages.

Fixes: 25520d55cd ("block: Inline blk_integrity in struct gendisk")
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 4.4+, needs backporting
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-21 14:17:27 -06:00
Dan Williams b0686260fe dax: introduce dax_direct_access()
Replace bdev_direct_access() with dax_direct_access() that uses
dax_device and dax_operations instead of a block_device and
block_device_operations for dax. Once all consumers of the old api have
been converted bdev_direct_access() will be deleted.

Given that block device partitioning decisions can cause dax page
alignment constraints to be violated this also introduces the
bdev_dax_pgoff() helper. It handles calculating a logical pgoff relative
to the dax_device and also checks for page alignment.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-04-20 11:57:52 -07:00
Dan Williams d8f07aee3f block: kill bdev_dax_capable()
This is leftover dead code that has since been replaced by
bdev_dax_supported().

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-04-20 11:57:52 -07:00
Christoph Hellwig 34045129b1 block_dev: use blkdev_issue_zerout for hole punches
This gets us support for non-discard efficient write of zeroes (e.g. NVMe)
and prepares for removing the discard_zeroes_data flag.

Also remove a pointless discard support check, which is done in
blkdev_issue_discard already.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>

Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-08 11:25:38 -06:00
Christoph Hellwig ee472d835c block: add a flags argument to (__)blkdev_issue_zeroout
Turn the existing discard flag into a new BLKDEV_ZERO_UNMAP flag with
similar semantics, but without referring to diѕcard.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-08 11:25:38 -06:00
Jan Kara f759741d9d block: Fix oops in locked_inode_to_wb_and_lock_list()
When block device is closed, we call inode_detach_wb() in __blkdev_put()
which sets inode->i_wb to NULL. That is contrary to expectations that
inode->i_wb stays valid once set during the whole inode's lifetime and
leads to oops in wb_get() in locked_inode_to_wb_and_lock_list() because
inode_to_wb() returned NULL.

The reason why we called inode_detach_wb() is not valid anymore though.
BDI is guaranteed to stay along until we call bdi_put() from
bdev_evict_inode() so we can postpone calling inode_detach_wb() to that
moment.

Also add a warning to catch if someone uses inode_detach_wb() in a
dangerous way.

Reported-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-03-22 20:11:33 -06:00
Jan Kara 03e2627988 block: Fix bdi assignment to bdev inode when racing with disk delete
When disk->fops->open() in __blkdev_get() returns -ERESTARTSYS, we
restart the process of opening the block device. However we forget to
switch bdev->bd_bdi back to noop_backing_dev_info and as a result bdev
inode will be pointing to a stale bdi. Fix the problem by setting
bdev->bd_bdi later when __blkdev_get() is already guaranteed to succeed.

Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-03-22 20:11:22 -06:00
Jan Kara a5a79d0001 block: Initialize bd_bdi on inode initialization
So far we initialized bd_bdi only in bdget(). That is fine for normal
bdev inodes however for the special case of the root inode of
blockdev_superblock that function is never called and thus bd_bdi is
left uninitialized. As a result bdev_evict_inode() may oops doing
bdi_put(root->bd_bdi) on that inode as can be seen when doing:

mount -t bdev none /mnt

Fix the problem by initializing bd_bdi when first allocating the inode
and then reinitializing bd_bdi in bdev_evict_inode().

Thanks to syzkaller team for finding the problem.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Fixes: b1d2dc5659 ("block: Make blk_get_backing_dev_info() safe without open bdev")
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-03-02 08:56:59 -07:00
Fabian Frederick 93407472a2 fs: add i_blocksize()
Replace all 1 << inode->i_blkbits and (1 << inode->i_blkbits) in fs
branch.

This patch also fixes multiple checkpatch warnings: WARNING: Prefer
'unsigned int' to bare use of 'unsigned'

Thanks to Andrew Morton for suggesting more appropriate function instead
of macro.

[geliangtang@gmail.com: truncate: use i_blocksize()]
  Link: http://lkml.kernel.org/r/9c8b2cd83c8f5653805d43debde9fa8817e02fc4.1484895804.git.geliangtang@gmail.com
Link: http://lkml.kernel.org/r/1481319905-10126-1-git-send-email-fabf@skynet.be
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27 18:43:46 -08:00
Jan Kara cccd9fb9ec block: Revalidate i_bdev reference in bd_aquire()
When a device gets removed, block device inode unhashed so that it is not
used anymore (bdget() will not find it anymore). Later when a new device
gets created with the same device number, we create new block device
inode. However there may be file system device inodes whose i_bdev still
points to the original block device inode and thus we get two active
block device inodes for the same device. They will share the same
gendisk so the only visible differences will be that page caches will
not be coherent and BDIs will be different (the old block device inode
still points to unregistered BDI).

Fix the problem by checking in bd_acquire() whether i_bdev still points
to active block device inode and re-lookup the block device if not. That
way any open of a block device happening after the old device has been
removed will get correct block device inode.

Tested-by: Lekshmi Pillai <lekshmicpillai@in.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-21 12:51:54 -07:00
Jens Axboe 818551e2b2 Merge branch 'for-4.11/next' into for-4.11/linus-merge
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-17 14:08:19 -07:00
Jan Kara b1d2dc5659 block: Make blk_get_backing_dev_info() safe without open bdev
Currenly blk_get_backing_dev_info() is not safe to be called when the
block device is not open as bdev->bd_disk is NULL in that case. However
inode_to_bdi() uses this function and may be call called from flusher
worker or other writeback related functions without bdev being open
which leads to crashes such as:

[113031.075540] Unable to handle kernel paging request for data at address 0x00000000
[113031.075614] Faulting instruction address: 0xc0000000003692e0
0:mon> t
[c0000000fb65f900] c00000000036cb6c writeback_sb_inodes+0x30c/0x590
[c0000000fb65fa10] c00000000036ced4 __writeback_inodes_wb+0xe4/0x150
[c0000000fb65fa70] c00000000036d33c wb_writeback+0x30c/0x450
[c0000000fb65fb40] c00000000036e198 wb_workfn+0x268/0x580
[c0000000fb65fc50] c0000000000f3470 process_one_work+0x1e0/0x590
[c0000000fb65fce0] c0000000000f38c8 worker_thread+0xa8/0x660
[c0000000fb65fd80] c0000000000fc4b0 kthread+0x110/0x130
[c0000000fb65fe30] c0000000000098f0 ret_from_kernel_thread+0x5c/0x6c

Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-02 08:20:53 -07:00
Jan Kara f44f1ab5a2 block: Unhash block device inodes on gendisk destruction
Currently, block device inodes stay around after corresponding gendisk
hash died until memory reclaim finds them and frees them. Since we will
make block device inode pin the bdi, we want to free the block device
inode as soon as the device goes away so that bdi does not stay around
unnecessarily. Furthermore we need to avoid issues when new device with
the same major,minor pair gets created since reusing the bdi structure
would be rather difficult in this case.

Unhashing block device inode on gendisk destruction nicely deals with
these problems. Once last block device inode reference is dropped (which
may be directly in del_gendisk()), the inode gets evicted. Furthermore if
the major,minor pair gets reallocated, we are guaranteed to get new
block device inode even if old block device inode is not yet evicted and
thus we avoid issues with possible reuse of bdi.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-02 08:18:41 -07:00
Christoph Hellwig 690e5325b8 block: fix use after free in __blkdev_direct_IO
We can't dereference the dio structure after submitting the last bio for
this request, as I/O completion might have happened before the code is
run. Introduce a local is_sync variable instead.

Fixes: 542ff7bf ("block: new direct I/O implementation")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Matias Bjørling <m@bjorling.me>
Tested-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-24 07:55:53 -07:00
Linus Torvalds 62f8c40592 Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block layer fixes from Jens Axboe:
 "A set of fixes for the current series, one fixing a regression with
  block size < page cache size in the alias series from Jan. Outside of
  that, two small cleanups for wbt from Bart, a nvme pull request from
  Christoph, and a few small fixes of documentation updates"

* 'for-linus' of git://git.kernel.dk/linux-block:
  block: fix up io_poll documentation
  block: Avoid that sparse complains about context imbalance in __wbt_wait()
  block: Make wbt_wait() definition consistent with declaration
  clean_bdev_aliases: Prevent cleaning blocks that are not in block range
  genhd: remove dead and duplicated scsi code
  block: add back plugging in __blkdev_direct_IO
  nvmet/fcloop: remove some logically dead code performing redundant ret checks
  nvmet: fix KATO offset in Set Features
  nvme/fc: simplify error handling of nvme_fc_create_hw_io_queues
  nvme/fc: correct some printk information
  nvme/scsi: Remove START STOP emulation
  nvme/pci: Delete misleading queue-wrap comment
  nvme/pci: Fix whitespace problem
  nvme: simplify stripe quirk
  nvme: update maintainers information
2017-01-04 09:03:37 -08:00
Linus Torvalds 7c0f6ba682 Replace <asm/uaccess.h> with <linux/uaccess.h> globally
This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-24 11:46:01 -08:00
Christoph Hellwig 64d656a162 block: add back plugging in __blkdev_direct_IO
This allows sending larger than 1 MB requests to devices that support
large I/O sizes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-12-22 11:48:20 -07:00
Shaohua Li 7a62a52333 block_dev: don't update file access position for sync direct IO
For sync direct IO, generic_file_direct_write/generic_file_read_iter
will update file access position. Don't duplicate the update in
.direct_IO. This cause my raid array can't assemble.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-12-13 21:07:08 -07:00
NeilBrown bcc7f5b4be block_dev: don't test bdev->bd_contains when it is not stable
bdev->bd_contains is not stable before calling __blkdev_get().
When __blkdev_get() is called on a parition with ->bd_openers == 0
it sets
  bdev->bd_contains = bdev;
which is not correct for a partition.
After a call to __blkdev_get() succeeds, ->bd_openers will be > 0
and then ->bd_contains is stable.

When FMODE_EXCL is used, blkdev_get() calls
   bd_start_claiming() ->  bd_prepare_to_claim() -> bd_may_claim()

This call happens before __blkdev_get() is called, so ->bd_contains
is not stable.  So bd_may_claim() cannot safely use ->bd_contains.
It currently tries to use it, and this can lead to a BUG_ON().

This happens when a whole device is already open with a bd_holder (in
use by dm in my particular example) and two threads race to open a
partition of that device for the first time, one opening with O_EXCL and
one without.

The thread that doesn't use O_EXCL gets through blkdev_get() to
__blkdev_get(), gains the ->bd_mutex, and sets bdev->bd_contains = bdev;

Immediately thereafter the other thread, using FMODE_EXCL, calls
bd_start_claiming() from blkdev_get().  This should fail because the
whole device has a holder, but because bdev->bd_contains == bdev
bd_may_claim() incorrectly reports success.
This thread continues and blocks on bd_mutex.

The first thread then sets bdev->bd_contains correctly and drops the mutex.
The thread using FMODE_EXCL then continues and when it calls bd_may_claim()
again in:
			BUG_ON(!bd_may_claim(bdev, whole, holder));
The BUG_ON fires.

Fix this by removing the dependency on ->bd_contains in
bd_may_claim().  As bd_may_claim() has direct access to the whole
device, it can simply test if the target bdev is the whole device.

Fixes: 6b4517a791 ("block: implement bd_claiming and claiming block")
Cc: stable@vger.kernel.org (v2.6.35+)
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-12-13 21:07:08 -07:00
Rabin Vincent af309226db block: protect iterate_bdevs() against concurrent close
If a block device is closed while iterate_bdevs() is handling it, the
following NULL pointer dereference occurs because bdev->b_disk is NULL
in bdev_get_queue(), which is called from blk_get_backing_dev_info() (in
turn called by the mapping_cap_writeback_dirty() call in
__filemap_fdatawrite_range()):

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000508
 IP: [<ffffffff81314790>] blk_get_backing_dev_info+0x10/0x20
 PGD 9e62067 PUD 9ee8067 PMD 0
 Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
 Modules linked in:
 CPU: 1 PID: 2422 Comm: sync Not tainted 4.5.0-rc7+ #400
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
 task: ffff880009f4d700 ti: ffff880009f5c000 task.ti: ffff880009f5c000
 RIP: 0010:[<ffffffff81314790>]  [<ffffffff81314790>] blk_get_backing_dev_info+0x10/0x20
 RSP: 0018:ffff880009f5fe68  EFLAGS: 00010246
 RAX: 0000000000000000 RBX: ffff88000ec17a38 RCX: ffffffff81a4e940
 RDX: 7fffffffffffffff RSI: 0000000000000000 RDI: ffff88000ec176c0
 RBP: ffff880009f5fe68 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000000000001 R11: 0000000000000000 R12: ffff88000ec17860
 R13: ffffffff811b25c0 R14: ffff88000ec178e0 R15: ffff88000ec17a38
 FS:  00007faee505d700(0000) GS:ffff88000fb00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 CR2: 0000000000000508 CR3: 0000000009e8a000 CR4: 00000000000006e0
 Stack:
  ffff880009f5feb8 ffffffff8112e7f5 0000000000000000 7fffffffffffffff
  0000000000000000 0000000000000000 7fffffffffffffff 0000000000000001
  ffff88000ec178e0 ffff88000ec17860 ffff880009f5fec8 ffffffff8112e81f
 Call Trace:
  [<ffffffff8112e7f5>] __filemap_fdatawrite_range+0x85/0x90
  [<ffffffff8112e81f>] filemap_fdatawrite+0x1f/0x30
  [<ffffffff811b25d6>] fdatawrite_one_bdev+0x16/0x20
  [<ffffffff811bc402>] iterate_bdevs+0xf2/0x130
  [<ffffffff811b2763>] sys_sync+0x63/0x90
  [<ffffffff815d4272>] entry_SYSCALL_64_fastpath+0x12/0x76
 Code: 0f 1f 44 00 00 48 8b 87 f0 00 00 00 55 48 89 e5 <48> 8b 80 08 05 00 00 5d
 RIP  [<ffffffff81314790>] blk_get_backing_dev_info+0x10/0x20
  RSP <ffff880009f5fe68>
 CR2: 0000000000000508
 ---[ end trace 2487336ceb3de62d ]---

The crash is easily reproducible by running the following command, if an
msleep(100) is inserted before the call to func() in iterate_devs():

 while :; do head -c1 /dev/nullb0; done > /dev/null & while :; do sync; done

Fix it by holding the bd_mutex across the func() call and only calling
func() if the bdev is opened.

Cc: stable@vger.kernel.org
Fixes: 5c0d6b60a0 ("vfs: Create function for iterating over block devices")
Reported-and-tested-by: Wei Fang <fangwei1@huawei.com>
Signed-off-by: Rabin Vincent <rabinv@axis.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-12-01 08:26:39 -07:00