linux-stable.git/drivers/block, branch v4.1.6

rbd: fix copyup completion race

2015-08-17T03:52:20+00:00

commit 2761713d35e370fd640b5781109f753066b746c4 upstream.

For write/discard obj_requests that involved a copyup method call, the
opcode of the first op is CEPH_OSD_OP_CALL and the ->callback is
rbd_img_obj_copyup_callback().  The latter frees copyup pages, sets
->xferred and delegates to rbd_img_obj_callback(), the "normal" image
object callback, for reporting to block layer and putting refs.

rbd_osd_req_callback() however treats CEPH_OSD_OP_CALL as a trivial op,
which means obj_request is marked done in rbd_osd_trivial_callback(),
*before* ->callback is invoked and rbd_img_obj_copyup_callback() has
a chance to run.  Marking obj_request done essentially means giving
rbd_img_obj_callback() a license to end it at any moment, so if another
obj_request from the same img_request is being completed concurrently,
rbd_img_obj_end_request() may very well be called on such prematurally
marked done request:


handle_reply()
  rbd_osd_req_callback()
    rbd_osd_trivial_callback()
    rbd_obj_request_complete()
    rbd_img_obj_copyup_callback()
    rbd_img_obj_callback()
                                    
                                    handle_reply()
                                      rbd_osd_req_callback()
                                        rbd_osd_trivial_callback()
      for_each_obj_request(obj_request->img_request) {
        rbd_img_obj_end_request(obj_request-1/2)
        rbd_img_obj_end_request(obj_request-2/2) <--
      }

Calling rbd_img_obj_end_request() on such a request leads to trouble,
in particular because its ->xfferred is 0.  We report 0 to the block
layer with blk_update_request(), get back 1 for "this request has more
data in flight" and then trip on

    rbd_assert(more ^ (which == img_request->obj_request_count));

with rhs (which == ...) being 1 because rbd_img_obj_end_request() has
been called for both requests and lhs (more) being 1 because we haven't
got a chance to set ->xfferred in rbd_img_obj_copyup_callback() yet.

To fix this, leverage that rbd wants to call class methods in only two
cases: one is a generic method call wrapper (obj_request is standalone)
and the other is a copyup (obj_request is part of an img_request).  So
make a dedicated handler for CEPH_OSD_OP_CALL and directly invoke
rbd_img_obj_copyup_callback() from it if obj_request is part of an
img_request, similar to how CEPH_OSD_OP_READ handler invokes
rbd_img_obj_request_read_callback().

Since rbd_img_obj_copyup_callback() is now being called from the OSD
request callback (only), it is renamed to rbd_osd_copyup_callback().

Cc: Alex Elder 
Signed-off-by: Ilya Dryomov 
Reviewed-by: Alex Elder 
Signed-off-by: Greg Kroah-Hartman

rbd: use GFP_NOIO in rbd_obj_request_create()

2015-08-03T16:29:18+00:00

commit 5a60e87603c4c533492c515b7f62578189b03c9c upstream.

rbd_obj_request_create() is called on the main I/O path, so we need to
use GFP_NOIO to make sure allocation doesn't blow back on us.  Not all
callers need this, but I'm still hardcoding the flag inside rather than
making it a parameter because a) this is going to stable, and b) those
callers shouldn't really use rbd_obj_request_create() and will be fixed
in the future.

More memory allocation fixes will follow.

Signed-off-by: Ilya Dryomov 
Reviewed-by: Alex Elder 
Signed-off-by: Greg Kroah-Hartman

block: loop: avoiding too many pending per work I/O

2015-08-03T16:29:07+00:00

commit 4d4e41aef9429872ea3b105e83426941f7185ab6 upstream.

If there are too many pending per work I/O, too many
high priority work thread can be generated so that
system performance can be effected.

This patch limits the max_active parameter of workqueue as 16.

This patch fixes Fedora 22 live booting performance
regression when it is booted from squashfs over dm
based on loop, and looks the following reasons are
related with the problem:

- not like other filesyststems(such as ext4), squashfs
is a bit special, and I observed that increasing I/O jobs
to access file in squashfs only improve I/O performance a
little, but it can make big difference for ext4

- nested loop: both squashfs.img and ext3fs.img are mounted
as loop block, and ext3fs.img is inside the squashfs

- during booting, lots of tasks may run concurrently

Fixes: b5dd2f6047ca108001328aac0e8588edd15f1778
Cc: Justin M. Forbes 
Signed-off-by: Ming Lei 
Acked-by: Tejun Heo 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

block: loop: convert to per-device workqueue

2015-08-03T16:29:07+00:00

commit f4aa4c7bbac6c4afdd4adccf90898c1a3685396d upstream.

Documentation/workqueue.txt:
	If there is dependency among multiple work items used
	during memory reclaim, they should be queued to separate
	wq each with WQ_MEM_RECLAIM.

Loop devices can be stacked, so we have to convert to per-device
workqueue. One example is Fedora live CD.

Fixes: b5dd2f6047ca108001328aac0e8588edd15f1778
Cc: Justin M. Forbes 
Signed-off-by: Ming Lei 
Acked-by: Tejun Heo 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'for-linus' of git://git.kernel.dk/linux-block

2015-06-12T18:35:19+00:00

Pull block layer fixes from Jens Axboe:
 "Remember about a week ago when I sent the last pull request for 4.1?
  Well, I lied.  Now, I don't want to shift the blame, but Dan, Ming,
  and Richard made a liar out of me.

  Here are three small patches that should go into 4.1.  More
  specifically, this pull request contains:

   - A Kconfig dependency for the pmem block driver, so it can't be
     selected if HAS_IOMEM isn't availble.  From Richard Weinberger.

   - A fix for genhd, making the ext_devt_lock softirq safe.  This makes
     lockdep happier, since we also end up grabbing this lock on release
     off the softirq path.  From Dan Williams.

   - A blk-mq software queue release fix from Ming Lei.

  Last two are headed to stable, first fixes an issue introduced in this
  cycle"

* 'for-linus' of git://git.kernel.dk/linux-block:
  block: pmem: Add dependency on HAS_IOMEM
  block: fix ext_dev_lock lockdep report
  blk-mq: free hctx->ctxs in queue's release handler

block: pmem: Add dependency on HAS_IOMEM

2015-06-11T21:54:58+00:00

Not all architectures have io memory.

Fixes:
drivers/block/pmem.c: In function ‘pmem_alloc’:
drivers/block/pmem.c:146:2: error: implicit declaration of function ‘ioremap_nocache’ [-Werror=implicit-function-declaration]
  pmem->virt_addr = ioremap_nocache(pmem->phys_addr, pmem->size);
  ^
drivers/block/pmem.c:146:18: warning: assignment makes pointer from integer without a cast [enabled by default]
  pmem->virt_addr = ioremap_nocache(pmem->phys_addr, pmem->size);
                  ^
drivers/block/pmem.c:182:2: error: implicit declaration of function ‘iounmap’ [-Werror=implicit-function-declaration]
  iounmap(pmem->virt_addr);
  ^

Signed-off-by: Richard Weinberger 
Reviewed-by: Ross Zwisler 
Signed-off-by: Jens Axboe

zram: clear disk io accounting when reset zram device

2015-06-10T23:43:43+00:00

Clear zram disk io accounting when resetting the zram device.  Otherwise
the residual io accounting stat will affect the diskstat in the next
zram active cycle.

Signed-off-by: Weijie Yang 
Acked-by: Sergey Senozhatsky 
Acked-by: Minchan Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

NVMe: fix type warning on 32-bit

2015-05-29T16:06:21+00:00

A recent change to the ioctl handling caused a new harmless
warning in the NVMe driver on all 32-bit machines:

drivers/block/nvme-core.c: In function 'nvme_submit_io':
drivers/block/nvme-core.c:1794:29: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]

In order to shup up that warning, this introduces a new
temporary variable that uses a double cast to extract
the pointer from an __u64 structure member.

Signed-off-by: Arnd Bergmann 
Fixes: a67a95134ff ("NVMe: Meta data handling through submit io ioctl")
Acked-by: Keith Busch 
Signed-off-by: Jens Axboe

nvme: fix kernel memory corruption with short INQUIRY buffers

2015-05-13T14:22:12+00:00

If userspace asks for an INQUIRY buffer smaller than 36 bytes, the SCSI
translation layer will happily write past the end of the INQUIRY buffer
allocation.

This is fairly easily reproducible by running the libiscsi test
suite and then starting an xfstests run.

Fixes: 4f1982 ("NVMe: Update SCSI Inquiry VPD 83h translation")
Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

Merge branch 'for-linus' of git://git.kernel.dk/linux-block

2015-05-09T02:49:35+00:00

Pull block fixes from Jens Axboe:
 "A collection of fixes since the merge window;

   - fix for a double elevator module release, from Chao Yu.  Ancient bug.

   - the splice() MORE flag fix from Christophe Leroy.

   - a fix for NVMe, fixing a patch that went in in the merge window.
     From Keith.

   - two fixes for blk-mq CPU hotplug handling, from Ming Lei.

   - bdi vs blockdev lifetime fix from Neil Brown, fixing and oops in md.

   - two blk-mq fixes from Shaohua, fixing a race on queue stop and a
     bad merge issue with FUA writes.

   - division-by-zero fix for writeback from Tejun.

   - a block bounce page accounting fix, making sure we inc/dec after
     bouncing so that pre/post IO pages match up.  From Wang YanQing"

* 'for-linus' of git://git.kernel.dk/linux-block:
  splice: sendfile() at once fails for big files
  blk-mq: don't lose requests if a stopped queue restarts
  blk-mq: fix FUA request hang
  block: destroy bdi before blockdev is unregistered.
  block:bounce: fix call inc_|dec_zone_page_state on different pages confuse value of NR_BOUNCE
  elevator: fix double release of elevator module
  writeback: use |1 instead of +1 to protect against div by zero
  blk-mq: fix CPU hotplug handling
  blk-mq: fix race between timeout and CPU hotplug
  NVMe: Fix VPD B0 max sectors translation