linux.git/fs/dax.c, branch v4.1

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

2015-04-27T00:22:07+00:00

Pull fourth vfs update from Al Viro:
 "d_inode() annotations from David Howells (sat in for-next since before
  the beginning of merge window) + four assorted fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  RCU pathwalk breakage when running into a symlink overmounting something
  fix I_DIO_WAKEUP definition
  direct-io: only inc/dec inode->i_dio_count for file systems
  fs/9p: fix readdir()
  VFS: assorted d_backing_inode() annotations
  VFS: fs/inode.c helpers: d_inode() annotations
  VFS: fs/cachefiles: d_backing_inode() annotations
  VFS: fs library helpers: d_inode() annotations
  VFS: assorted weird filesystems: d_inode() annotations
  VFS: normal filesystems (and lustre): d_inode() annotations
  VFS: security/: d_inode() annotations
  VFS: security/: d_backing_inode() annotations
  VFS: net/: d_inode() annotations
  VFS: net/unix: d_backing_inode() annotations
  VFS: kernel/: d_inode() annotations
  VFS: audit: d_backing_inode() annotations
  VFS: Fix up some ->d_inode accesses in the chelsio driver
  VFS: Cachefiles should perform fs modifications on the top layer only
  VFS: AF_UNIX sockets should call mknod on the top layer only

direct-io: only inc/dec inode->i_dio_count for file systems

2015-04-24T19:45:28+00:00

do_blockdev_direct_IO() increments and decrements the inode
->i_dio_count for each IO operation. It does this to protect against
truncate of a file. Block devices don't need this sort of protection.

For a capable multiqueue setup, this atomic int is the only shared
state between applications accessing the device for O_DIRECT, and it
presents a scaling wall for that. In my testing, as much as 30% of
system time is spent incrementing and decrementing this value. A mixed
read/write workload improved from ~2.5M IOPS to ~9.6M IOPS, with
better latencies too. Before:

clat percentiles (usec):
 |  1.00th=[   33],  5.00th=[   34], 10.00th=[   34], 20.00th=[   34],
 | 30.00th=[   34], 40.00th=[   34], 50.00th=[   35], 60.00th=[   35],
 | 70.00th=[   35], 80.00th=[   35], 90.00th=[   37], 95.00th=[   80],
 | 99.00th=[   98], 99.50th=[  151], 99.90th=[  155], 99.95th=[  155],
 | 99.99th=[  165]

After:

clat percentiles (usec):
 |  1.00th=[   95],  5.00th=[  108], 10.00th=[  129], 20.00th=[  149],
 | 30.00th=[  155], 40.00th=[  161], 50.00th=[  167], 60.00th=[  171],
 | 70.00th=[  177], 80.00th=[  185], 90.00th=[  201], 95.00th=[  270],
 | 99.00th=[  390], 99.50th=[  398], 99.90th=[  418], 99.95th=[  422],
 | 99.99th=[  438]

In other setups, Robert Elliott reported seeing good performance
improvements:

https://lkml.org/lkml/2015/4/3/557

The more applications accessing the device, the worse it gets.

Add a new direct-io flags, DIO_SKIP_DIO_COUNT, which tells
do_blockdev_direct_IO() that it need not worry about incrementing
or decrementing the inode i_dio_count for this caller.

Cc: Andrew Morton 
Cc: Christoph Hellwig 
Cc: Theodore Ts'o 
Cc: Elliott, Robert (Server Storage) 
Cc: Al Viro 
Signed-off-by: Jens Axboe 
Signed-off-by: Al Viro

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

2015-04-17T03:27:56+00:00

Pull third hunk of vfs changes from Al Viro:
 "This contains the ->direct_IO() changes from Omar + saner
  generic_write_checks() + dealing with fcntl()/{read,write}() races
  (mirroring O_APPEND/O_DIRECT into iocb->ki_flags and instead of
  repeatedly looking at ->f_flags, which can be changed by fcntl(2),
  check ->ki_flags - which cannot) + infrastructure bits for dhowells'
  d_inode annotations + Christophs switch of /dev/loop to
  vfs_iter_write()"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (30 commits)
  block: loop: switch to VFS ITER_BVEC
  configfs: Fix inconsistent use of file_inode() vs file->f_path.dentry->d_inode
  VFS: Make pathwalk use d_is_reg() rather than S_ISREG()
  VFS: Fix up debugfs to use d_is_dir() in place of S_ISDIR()
  VFS: Combine inode checks with d_is_negative() and d_is_positive() in pathwalk
  NFS: Don't use d_inode as a variable name
  VFS: Impose ordering on accesses of d_inode and d_flags
  VFS: Add owner-filesystem positive/negative dentry checks
  nfs: generic_write_checks() shouldn't be done on swapout...
  ocfs2: use __generic_file_write_iter()
  mirror O_APPEND and O_DIRECT into iocb->ki_flags
  switch generic_write_checks() to iocb and iter
  ocfs2: move generic_write_checks() before the alignment checks
  ocfs2_file_write_iter: stop messing with ppos
  udf_file_write_iter: reorder and simplify
  fuse: ->direct_IO() doesn't need generic_write_checks()
  ext4_file_write_iter: move generic_write_checks() up
  xfs_file_aio_write_checks: switch to iocb/iov_iter
  generic_write_checks(): drop isblk argument
  blkdev_write_iter: expand generic_file_checks() call in there
  ...

dax: use pfn_mkwrite to update c/mtime + freeze protection

2015-04-15T23:35:20+00:00

From: Yigal Korman 

[v1]
Without this patch, c/mtime is not updated correctly when mmap'ed page is
first read from and then written to.

A new xfstest is submitted for testing this (generic/080)

[v2]
Jan Kara has pointed out that if we add the
sb_start/end_pagefault pair in the new pfn_mkwrite we
are then fixing another bug where: A user could start
writing to the page while filesystem is frozen.

Signed-off-by: Yigal Korman 
Signed-off-by: Boaz Harrosh 
Reviewed-by: Jan Kara 
Cc: Matthew Wilcox 
Cc: Dave Chinner 
Cc: Hugh Dickins 
Cc: Mel Gorman 
Cc: Kirill A. Shutemov 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Remove rw from dax_{do_,}io()

2015-04-12T02:29:44+00:00

And use iov_iter_rw() instead.

Signed-off-by: Omar Sandoval 
Signed-off-by: Al Viro

dax: add dax_zero_page_range

2015-02-17T01:56:04+00:00

This new function allows us to support hole-punch for DAX files by zeroing
a partial page, as opposed to the dax_truncate_page() function which can
only truncate to the end of the page.  Reimplement dax_truncate_page() to
call dax_zero_page_range().

[ross.zwisler@linux.intel.com: ported to 3.13-rc2]
[akpm@linux-foundation.org: fix typos in comments]
Signed-off-by: Matthew Wilcox 
Signed-off-by: Ross Zwisler 
Cc: Andreas Dilger 
Cc: Boaz Harrosh 
Cc: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Jan Kara 
Cc: Jens Axboe 
Cc: Kirill A. Shutemov 
Cc: Mathieu Desnoyers 
Cc: Randy Dunlap 
Cc: Theodore Ts'o 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

dax,ext2: replace xip_truncate_page with dax_truncate_page

2015-02-17T01:56:03+00:00

It takes a get_block parameter just like nobh_truncate_page() and
block_truncate_page()

Signed-off-by: Matthew Wilcox 
Reviewed-by: Mathieu Desnoyers 
Cc: Andreas Dilger 
Cc: Boaz Harrosh 
Cc: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Jan Kara 
Cc: Jens Axboe 
Cc: Kirill A. Shutemov 
Cc: Randy Dunlap 
Cc: Ross Zwisler 
Cc: Theodore Ts'o 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

dax,ext2: replace the XIP page fault handler with the DAX page fault handler

2015-02-17T01:56:03+00:00

Instead of calling aops->get_xip_mem from the fault handler, the
filesystem passes a get_block_t that is used to find the appropriate
blocks.

This requires that all architectures implement copy_user_page().  At the
time of writing, mips and arm do not.  Patches exist and are in progress.

[akpm@linux-foundation.org: remap_file_pages went away]
Signed-off-by: Matthew Wilcox 
Reviewed-by: Jan Kara 
Cc: Andreas Dilger 
Cc: Boaz Harrosh 
Cc: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Jens Axboe 
Cc: Kirill A. Shutemov 
Cc: Mathieu Desnoyers 
Cc: Randy Dunlap 
Cc: Ross Zwisler 
Cc: Theodore Ts'o 
Cc: Russell King 
Cc: Ralf Baechle 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

dax,ext2: replace ext2_clear_xip_target with dax_clear_blocks

2015-02-17T01:56:03+00:00

This is practically generic code; other filesystems will want to call it
from other places, but there's nothing ext2-specific about it.

Make it a little more generic by allowing it to take a count of the number
of bytes to zero rather than fixing it to a single page.  Thanks to Dave
Hansen for suggesting that I need to call cond_resched() if zeroing more
than one page.

Signed-off-by: Matthew Wilcox 
Cc: Andreas Dilger 
Cc: Boaz Harrosh 
Cc: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Jan Kara 
Cc: Jens Axboe 
Cc: Kirill A. Shutemov 
Cc: Mathieu Desnoyers 
Cc: Randy Dunlap 
Cc: Ross Zwisler 
Cc: Theodore Ts'o 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

dax,ext2: replace XIP read and write with DAX I/O

2015-02-17T01:56:03+00:00

Use the generic AIO infrastructure instead of custom read and write
methods.  In addition to giving us support for AIO, this adds the missing
locking between read() and truncate().

Signed-off-by: Matthew Wilcox 
Reviewed-by: Ross Zwisler 
Reviewed-by: Jan Kara 
Cc: Andreas Dilger 
Cc: Boaz Harrosh 
Cc: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Jens Axboe 
Cc: Kirill A. Shutemov 
Cc: Mathieu Desnoyers 
Cc: Randy Dunlap 
Cc: Theodore Ts'o 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds