linux.git/fs/block_dev.c, branch v3.18-rc2

Merge branch 'for-3.18/core' of git://git.kernel.dk/linux-block

2014-10-18T18:53:51+00:00

Pull core block layer changes from Jens Axboe:
 "This is the core block IO pull request for 3.18.  Apart from the new
  and improved flush machinery for blk-mq, this is all mostly bug fixes
  and cleanups.

   - blk-mq timeout updates and fixes from Christoph.

   - Removal of REQ_END, also from Christoph.  We pass it through the
     ->queue_rq() hook for blk-mq instead, freeing up one of the request
     bits.  The space was overly tight on 32-bit, so Martin also killed
     REQ_KERNEL since it's no longer used.

   - blk integrity updates and fixes from Martin and Gu Zheng.

   - Update to the flush machinery for blk-mq from Ming Lei.  Now we
     have a per hardware context flush request, which both cleans up the
     code should scale better for flush intensive workloads on blk-mq.

   - Improve the error printing, from Rob Elliott.

   - Backing device improvements and cleanups from Tejun.

   - Fixup of a misplaced rq_complete() tracepoint from Hannes.

   - Make blk_get_request() return error pointers, fixing up issues
     where we NULL deref when a device goes bad or missing.  From Joe
     Lawrence.

   - Prep work for drastically reducing the memory consumption of dm
     devices from Junichi Nomura.  This allows creating clone bio sets
     without preallocating a lot of memory.

   - Fix a blk-mq hang on certain combinations of queue depths and
     hardware queues from me.

   - Limit memory consumption for blk-mq devices for crash dump
     scenarios and drivers that use crazy high depths (certain SCSI
     shared tag setups).  We now just use a single queue and limited
     depth for that"

* 'for-3.18/core' of git://git.kernel.dk/linux-block: (58 commits)
  block: Remove REQ_KERNEL
  blk-mq: allocate cpumask on the home node
  bio-integrity: remove the needless fail handle of bip_slab creating
  block: include func name in __get_request prints
  block: make blk_update_request print prefix match ratelimited prefix
  blk-merge: don't compute bi_phys_segments from bi_vcnt for cloned bio
  block: fix alignment_offset math that assumes io_min is a power-of-2
  blk-mq: Make bt_clear_tag() easier to read
  blk-mq: fix potential hang if rolling wakeup depth is too high
  block: add bioset_create_nobvec()
  block: use bio_clone_fast() in blk_rq_prep_clone()
  block: misplaced rq_complete tracepoint
  sd: Honor block layer integrity handling flags
  block: Replace strnicmp with strncasecmp
  block: Add T10 Protection Information functions
  block: Don't merge requests if integrity flags differ
  block: Integrity checksum flag
  block: Relocate bio integrity flags
  block: Add a disk flag to block integrity profile
  block: Add prefix to block integrity profile flags
  ...

block_dev: implement readpages() to optimize sequential read

2014-10-10T02:25:53+00:00

Sequential read from a block device is expected to be equal or faster than
from the file on a filesystem.  But it is not correct due to the lack of
effective readpages() in the address space operations for block device.

This implements readpages() operation for block device by using
mpage_readpages() which can create multipage BIOs instead of BIOs for each
page and reduce system CPU time consumption.

Install 1GB of RAM disk storage:

	# modprobe scsi_debug dev_size_mb=1024 delay=0

Sequential read from file on a filesystem:

	# mkfs.ext4 /dev/$DEV
	# mount /dev/$DEV /mnt
	# fio --name=t --size=512m --rw=read --filename=/mnt/file
	...
	  read : io=524288KB, bw=2133.4MB/s, iops=546133, runt=   240msec

Sequential read from a block device:
	# fio --name=t --size=512m --rw=read --filename=/dev/$DEV
	...
(Without this commit)
	  read : io=524288KB, bw=1700.2MB/s, iops=435455, runt=   301msec

(With this commit)
	  read : io=524288KB, bw=2160.4MB/s, iops=553046, runt=   237msec

Signed-off-by: Akinobu Mita 
Cc: Jens Axboe 
Cc: Alexander Viro 
Cc: Jeff Moyer 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

bdi: reimplement bdev_inode_switch_bdi()

2014-09-08T16:00:43+00:00

A block_device may be attached to different gendisks and thus
different bdis over time.  bdev_inode_switch_bdi() is used to switch
the associated bdi.  The function assumes that the inode could be
dirty and transfers it between bdis if so.  This is a bit nasty in
that it reaches into bdi internals.

This patch reimplements the function so that it writes out the inode
if dirty.  This is a lot simpler and can be implemented without
exposing bdi internals.

Signed-off-by: Tejun Heo 
Cc: Alexander Viro 
Signed-off-by: Jens Axboe

block, bdi: an active gendisk always has a request_queue associated with it

2014-09-08T16:00:35+00:00

bdev_get_queue() returns the request_queue associated with the
specified block_device.  blk_get_backing_dev_info() makes use of
bdev_get_queue() to determine the associated bdi given a block_device.

All the callers of bdev_get_queue() including
blk_get_backing_dev_info() assume that bdev_get_queue() may return
NULL and implement NULL handling; however, bdev_get_queue() requires
the passed in block_device is opened and attached to its gendisk.
Because an active gendisk always has a valid request_queue associated
with it, bdev_get_queue() can never return NULL and neither can
blk_get_backing_dev_info().

Make it clear that neither of the two functions can return NULL and
remove NULL handling from all the callers.

Signed-off-by: Tejun Heo 
Cc: Chris Mason 
Cc: Dave Chinner 
Signed-off-by: Jens Axboe

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

2014-06-12T17:30:18+00:00

Pull vfs updates from Al Viro:
 "This the bunch that sat in -next + lock_parent() fix.  This is the
  minimal set; there's more pending stuff.

  In particular, I really hope to get acct.c fixes merged this cycle -
  we need that to deal sanely with delayed-mntput stuff.  In the next
  pile, hopefully - that series is fairly short and localized
  (kernel/acct.c, fs/super.c and fs/namespace.c).  In this pile: more
  iov_iter work.  Most of prereqs for ->splice_write with sane locking
  order are there and Kent's dio rewrite would also fit nicely on top of
  this pile"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (70 commits)
  lock_parent: don't step on stale ->d_parent of all-but-freed one
  kill generic_file_splice_write()
  ceph: switch to iter_file_splice_write()
  shmem: switch to iter_file_splice_write()
  nfs: switch to iter_splice_write_file()
  fs/splice.c: remove unneeded exports
  ocfs2: switch to iter_file_splice_write()
  ->splice_write() via ->write_iter()
  bio_vec-backed iov_iter
  optimize copy_page_{to,from}_iter()
  bury generic_file_aio_{read,write}
  lustre: get rid of messing with iovecs
  ceph: switch to ->write_iter()
  ceph_sync_direct_write: stop poking into iov_iter guts
  ceph_sync_read: stop poking into iov_iter guts
  new helper: copy_page_from_iter()
  fuse: switch to ->write_iter()
  btrfs: switch to ->write_iter()
  ocfs2: switch to ->write_iter()
  xfs: switch to ->write_iter()
  ...

->splice_write() via ->write_iter()

2014-06-12T04:18:51+00:00

iter_file_splice_write() - a ->splice_write() instance that gathers the
pipe buffers, builds a bio_vec-based iov_iter covering those and feeds
it to ->write_iter().  A bunch of simple cases coverted to that...

[AV: fixed the braino spotted by Cyrill]

Signed-off-by: Al Viro

fs/block_dev.c: add bdev_read_page() and bdev_write_page()

2014-06-04T23:54:02+00:00

A block device driver may choose to provide a rw_page operation.  These
will be called when the filesystem is attempting to do page sized I/O to
page cache pages (ie not for direct I/O).  This does preclude I/Os that
are larger than page size, so this may only be a performance gain for
some devices.

Signed-off-by: Matthew Wilcox 
Tested-by: Dheeraj Reddy 
Cc: Dave Chinner 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

blkdev_aio_write() - turn into blkdev_write_iter()

2014-05-06T21:38:01+00:00

Signed-off-by: Al Viro

fs/block_dev.c: switch to ->read_iter()

2014-05-06T21:37:59+00:00

Signed-off-by: Al Viro

blkdev_aio_read(): switch to generic_file_read_iter(), get rid of iov_shorten()

2014-05-06T21:32:54+00:00

Signed-off-by: Al Viro