linux-toradex.git/drivers/block/loop.c, branch v4.2.8

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2015-07-05T02:36:06+00:00

Pull more vfs updates from Al Viro:
 "Assorted VFS fixes and related cleanups (IMO the most interesting in
  that part are f_path-related things and Eric's descriptor-related
  stuff).  UFS regression fixes (it got broken last cycle).  9P fixes.
  fs-cache series, DAX patches, Jan's file_remove_suid() work"

[ I'd say this is much more than "fixes and related cleanups".  The
  file_table locking rule change by Eric Dumazet is a rather big and
  fundamental update even if the patch isn't huge.   - Linus ]

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (49 commits)
  9p: cope with bogus responses from server in p9_client_{read,write}
  p9_client_write(): avoid double p9_free_req()
  9p: forgetting to cancel request on interrupted zero-copy RPC
  dax: bdev_direct_access() may sleep
  block: Add support for DAX reads/writes to block devices
  dax: Use copy_from_iter_nocache
  dax: Add block size note to documentation
  fs/file.c: __fget() and dup2() atomicity rules
  fs/file.c: don't acquire files->file_lock in fd_install()
  fs:super:get_anon_bdev: fix race condition could cause dev exceed its upper limitation
  vfs: avoid creation of inode number 0 in get_next_ino
  namei: make set_root_rcu() return void
  make simple_positive() public
  ufs: use dir_pages instead of ufs_dir_pages()
  pagemap.h: move dir_pages() over there
  remove the pointless include of lglock.h
  fs: cleanup slight list_entry abuse
  xfs: Correctly lock inode when removing suid and file capabilities
  fs: Call security_ops->inode_killpriv on truncate
  fs: Provide function telling whether file_remove_privs() will do anything
  ...

Merge branch 'for-4.2/drivers' of git://git.kernel.dk/linux-block

2015-06-25T22:12:50+00:00

Pull block driver updates from Jens Axboe:
 "This contains:

   - a few race fixes for null_blk, from Akinobu Mita.

   - a series of fixes for mtip32xx, from Asai Thambi and Selvan Mani at
     Micron.

   - NVMe:
        * Fix for missing error return on allocation failure, from Axel
          Lin.

        * Code consolidation and cleanups from Christoph.

        * Memory barrier addition, syncing queue count and queue
          pointers. From Jon Derrick.

        * Various fixes from Keith, an addition to support user
          issue reset from sysfs or ioctl, and automatic namespace
          rescan.

        * Fix from Matias, avoiding losing some request flags when
          marking the request failfast.

   - small cleanups and sparse fixups for ps3vram.  From Geert
     Uytterhoeven and Geoff Lavand.

   - s390/dasd dead code removal, from Jarod Wilson.

   - a set of fixes and optimizations for loop, from Ming Lei.

   - conversion to blkdev_reread_part() of loop, dasd, ndb.  From Ming
     Lei.

   - updates to cciss.  From Tomas Henzl"

* 'for-4.2/drivers' of git://git.kernel.dk/linux-block: (44 commits)
  mtip32xx: Fix accessing freed memory
  block: nvme-scsi: Catch kcalloc failure
  NVMe: Fix IO for extended metadata formats
  nvme: don't overwrite req->cmd_flags on sync cmd
  mtip32xx: increase wait time for hba reset
  mtip32xx: fix minor number
  mtip32xx: remove unnecessary sleep in mtip_ftl_rebuild_poll()
  mtip32xx: fix crash on surprise removal of the drive
  mtip32xx: Abort I/O during secure erase operation
  mtip32xx: fix incorrectly setting MTIP_DDF_SEC_LOCK_BIT
  mtip32xx: remove unused variable 'port->allocated'
  mtip32xx: fix rmmod issue
  MAINTAINERS: Update ps3vram block driver
  block/ps3vram: Remove obsolete reference to MTD
  block/ps3vram: Fix sparse warnings
  NVMe: Automatic namespace rescan
  NVMe: Memory barrier before queue_count is incremented
  NVMe: add sysfs and ioctl controller reset
  null_blk: restart request processing on completion handler
  null_blk: prevent timer handler running on a different CPU where started
  ...

vfs: add file_path() helper

2015-06-23T22:00:05+00:00

Turn
	d_path(&file->f_path, ...);
into
	file_path(file, ...);

Signed-off-by: Miklos Szeredi 
Signed-off-by: Al Viro

loop: remove (now) unused 'out' label

2015-05-20T15:54:35+00:00

gcc, righfully, complains:

drivers/block/loop.c:1369:1: warning: label 'out' defined but not used [-Wunused-label]

Kill it.

Signed-off-by: Jens Axboe

block: loop: fix another reread part failure

2015-05-20T15:06:11+00:00

loop_clr_fd() can be run piggyback with lo_release(), and
under this situation, reread partition may always fail because
bd_mutex has been held already.

This patch detects the situation by the reference count, and
call __blkdev_reread_part() to avoid acquiring the lock again.

In the meantime, this patch switches to new kernel APIs
of blkdev_reread_part() and __blkdev_reread_part().

Reviewed-by: Christoph Hellwig 
Tested-by: Jarod Wilson 
Acked-by: Jarod Wilson 
Signed-off-by: Jarod Wilson 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

block: loop: don't hold lo_ctl_mutex in lo_open

2015-05-20T15:06:09+00:00

The lo_ctl_mutex is held for running all ioctl handlers, and
in some ioctl handlers, ioctl_by_bdev(BLKRRPART) is called for
rereading partitions, which requires bd_mutex.

So it is easy to cause failure because trylock(bd_mutex) may
fail inside blkdev_reread_part(), and follows the lock context:

blkid or other application:
	->open()
		->mutex_lock(bd_mutex)
		->lo_open()
			->mutex_lock(lo_ctl_mutex)

losetup(set fd ioctl):
	->mutex_lock(lo_ctl_mutex)
	->ioctl_by_bdev(BLKRRPART)
		->trylock(bd_mutex)

This patch trys to eliminate the ABBA lock dependency by removing
lo_ctl_mutext in lo_open() with the following approach:

1) make lo_refcnt as atomic_t and avoid acquiring lo_ctl_mutex in lo_open():
	- for open vs. add/del loop, no any problem because of loop_index_mutex
	- freeze request queue during clr_fd, so I/O can't come until
	  clearing fd is completed, like the effect of holding lo_ctl_mutex
	  in lo_open
	- both open() and release() have been serialized by bd_mutex already

2) don't hold lo_ctl_mutex for decreasing/checking lo_refcnt in
lo_release(), then lo_ctl_mutex is only required for the last release.

Reviewed-by: Christoph Hellwig 
Tested-by: Jarod Wilson 
Acked-by: Jarod Wilson 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

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

2015-05-05T19:46:55+00:00

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: stable@vger.kernel.org (v4.0)
Cc: Justin M. Forbes 
Signed-off-by: Ming Lei 
Acked-by: Tejun Heo 
Signed-off-by: Jens Axboe

block: loop: convert to per-device workqueue

2015-05-05T19:46:53+00:00

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: stable@vger.kernel.org (v4.0)
Cc: Justin M. Forbes 
Signed-off-by: Ming Lei 
Acked-by: Tejun Heo 
Signed-off-by: Jens Axboe

block: destroy bdi before blockdev is unregistered.

2015-04-27T16:27:20+00:00

Because of the peculiar way that md devices are created (automatically
when the device node is opened), a new device can be created and
registered immediately after the
	blk_unregister_region(disk_devt(disk), disk->minors);
call in del_gendisk().

Therefore it is important that all visible artifacts of the previous
device are removed before this call.  In particular, the 'bdi'.

Since:
commit c4db59d31e39ea067c32163ac961e9c80198fd37
Author: Christoph Hellwig 
    fs: don't reassign dirty inodes to default_backing_dev_info

moved the
   device_unregister(bdi->dev);
call from bdi_unregister() to bdi_destroy() it has been quite easy to
lose a race and have a new (e.g.) "md127" be created after the
blk_unregister_region() call and before bdi_destroy() is ultimately
called by the final 'put_disk', which must come after del_gendisk().

The new device finds that the bdi name is already registered in sysfs
and complains

> [ 9627.630029] WARNING: CPU: 18 PID: 3330 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x5a/0x70()
> [ 9627.630032] sysfs: cannot create duplicate filename '/devices/virtual/bdi/9:127'

We can fix this by moving the bdi_destroy() call out of
blk_release_queue() (which can happen very late when a refcount
reaches zero) and into blk_cleanup_queue() - which happens exactly when the md
device driver calls it.

Then it is only necessary for md to call blk_cleanup_queue() before
del_gendisk().  As loop.c devices are also created on demand by
opening the device node, we make the same change there.

Fixes: c4db59d31e39ea067c32163ac961e9c80198fd37
Reported-by: Azat Khuzhin 
Cc: Christoph Hellwig 
Cc: stable@vger.kernel.org (v4.0)
Signed-off-by: NeilBrown 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

block: loop: switch to VFS ITER_BVEC

2015-04-15T19:06:33+00:00

Signed-off-by: Christoph Hellwig 
Signed-off-by: Al Viro