linux.git/fs/xfs, branch v4.5

Merge tag 'xfs-for-linus-4.5-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs

2016-03-11T18:21:32+00:00

Pull xfs fixes from Dave Chinner:
 "This is a fix for a regression introduced in 4.5-rc1 by the new torn
  log write detection code.  The regression only affects people moving a
  clean filesystem between machines/kernels of different architecture
  (such as changing between 32 bit and 64 bit kernels), but this is the
  recommended (and only!) safe way to migrate a filesystem between
  architectures so we really need to ensure it works.

  The changes are larger than I'd prefer right at the end of the release
  cycle, but the majority of the change is just factoring code to enable
  the detection of a clean log at the correct time to avoid this issue.

  Changes:

   - Only perform torn log write detection on dirty logs.  This prevents
     failures being detected due to a clean filesystem being moved
     between machines or kernels of different architectures (e.g.  32 ->
     64 bit, BE -> LE, etc).  This fixes a regression introduced by the
     torn log write detection in 4.5-rc1"

* tag 'xfs-for-linus-4.5-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs:
  xfs: only run torn log write detection on dirty logs
  xfs: refactor in-core log state update to helper
  xfs: refactor unmount record detection into helper
  xfs: separate log head record discovery from verification

xfs: only run torn log write detection on dirty logs

2016-03-06T21:22:22+00:00

XFS uses CRC verification over a sub-range of the head of the log to
detect and handle torn writes. This torn log write detection currently
runs unconditionally at mount time, regardless of whether the log is
dirty or clean. This is problematic in cases where a filesystem might
end up being moved across different, incompatible (i.e., opposite
byte-endianness) architectures.

The problem lies in the fact that log data is not necessarily written in
an architecture independent format. For example, certain bits of data
are written in native endian format. Further, the size of certain log
data structures differs (i.e., struct xlog_rec_header) depending on the
word size of the cpu. This leads to false positive crc verification
errors and ultimately failed mounts when a cleanly unmounted filesystem
is mounted on a system with an incompatible architecture from data that
was written near the head of the log.

Update the log head/tail discovery code to run torn write detection only
when the log is not clean. This means something other than an unmount
record resides at the head of the log and log recovery is imminent. It
is a requirement to run log recovery on the same type of host that had
written the content of the dirty log and therefore CRC failures are
legitimate corruptions in that scenario.

Reported-by: Jan Beulich 
Tested-by: Jan Beulich 
Signed-off-by: Brian Foster 
Reviewed-by: Dave Chinner 
Signed-off-by: Dave Chinner

xfs: refactor in-core log state update to helper

2016-03-06T21:22:22+00:00

Once the record at the head of the log is identified and verified, the
in-core log state is updated based on the record. This includes
information such as the current head block and cycle, the start block of
the last record written to the log, the tail lsn, etc.

Once torn write detection is conditional, this logic will need to be
reused. Factor the code to update the in-core log data structures into a
new helper function. This patch does not change behavior.

Signed-off-by: Brian Foster 
Reviewed-by: Dave Chinner 
Signed-off-by: Dave Chinner

xfs: refactor unmount record detection into helper

2016-03-06T21:22:22+00:00

Once the mount sequence has identified the head and tail blocks of the
physical log, the record at the head of the log is located and examined
for an unmount record to determine if the log is clean. This currently
occurs after torn write verification of the head region of the log.

This must ultimately be separated from torn write verification and may
need to be called again if the log head is walked back due to a torn
write (to determine whether the new head record is an unmount record).
Separate this logic into a new helper function. This patch does not
change behavior.

Signed-off-by: Brian Foster 
Reviewed-by: Dave Chinner 
Signed-off-by: Dave Chinner

xfs: separate log head record discovery from verification

2016-03-06T21:22:22+00:00

The code that locates the log record at the head of the log is buried in
the log head verification function. This is fine when torn write
verification occurs unconditionally, but this behavior is problematic
for filesystems that might be moved across systems with different
architectures.

In preparation for separating examination of the log head for unmount
records from torn write detection, lift the record location logic out of
the log verification function and into the caller. This patch does not
change behavior.

Signed-off-by: Brian Foster 
Reviewed-by: Dave Chinner 
Signed-off-by: Dave Chinner

dax: move writeback calls into the filesystems

2016-02-27T18:28:52+00:00

Previously calls to dax_writeback_mapping_range() for all DAX filesystems
(ext2, ext4 & xfs) were centralized in filemap_write_and_wait_range().

dax_writeback_mapping_range() needs a struct block_device, and it used
to get that from inode->i_sb->s_bdev.  This is correct for normal inodes
mounted on ext2, ext4 and XFS filesystems, but is incorrect for DAX raw
block devices and for XFS real-time files.

Instead, call dax_writeback_mapping_range() directly from the filesystem
->writepages function so that it can supply us with a valid block
device.  This also fixes DAX code to properly flush caches in response
to sync(2).

Signed-off-by: Ross Zwisler 
Signed-off-by: Jan Kara 
Cc: Al Viro 
Cc: Dan Williams 
Cc: Dave Chinner 
Cc: Jens Axboe 
Cc: Matthew Wilcox 
Cc: Theodore Ts'o 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

dax: give DAX clearing code correct bdev

2016-02-27T18:28:52+00:00

dax_clear_blocks() needs a valid struct block_device and previously it
was using inode->i_sb->s_bdev in all cases.  This is correct for normal
inodes on mounted ext2, ext4 and XFS filesystems, but is incorrect for
DAX raw block devices and for XFS real-time devices.

Instead, rename dax_clear_blocks() to dax_clear_sectors(), and change
its arguments to take a bdev and a sector instead of an inode and a
block.  This better reflects what the function does, and it allows the
filesystem and raw block device code to pass in an appropriate struct
block_device.

Signed-off-by: Ross Zwisler 
Suggested-by: Dan Williams 
Reviewed-by: Jan Kara 
Cc: Theodore Ts'o 
Cc: Al Viro 
Cc: Dave Chinner 
Cc: Jens Axboe 
Cc: Matthew Wilcox 
Cc: Ross Zwisler 
Cc: Theodore Ts'o 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

xfs: fix endianness error when checking log block crc on big endian platforms

2016-02-08T00:03:58+00:00

Since the checksum function and the field are both __le32, don't
perform endian conversion when comparing the two.  This fixes mount
failures on ppc64.

Signed-off-by: Darrick J. Wong 
Reviewed-by: Brian Foster 
Signed-off-by: Dave Chinner

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

2016-01-23T20:24:56+00:00

Pull final vfs updates from Al Viro:

 - The ->i_mutex wrappers (with small prereq in lustre)

 - a fix for too early freeing of symlink bodies on shmem (they need to
   be RCU-delayed) (-stable fodder)

 - followup to dedupe stuff merged this cycle

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  vfs: abort dedupe loop if fatal signals are pending
  make sure that freeing shmem fast symlinks is RCU-delayed
  wrappers for ->i_mutex access
  lustre: remove unused declaration

xfs: call dax_pfn_mkwrite() for DAX fsync/msync

2016-01-23T01:02:18+00:00

To properly support the new DAX fsync/msync infrastructure filesystems
need to call dax_pfn_mkwrite() so that DAX can track when user pages are
dirtied.

Signed-off-by: Ross Zwisler 
Cc: "H. Peter Anvin" 
Cc: "J. Bruce Fields" 
Cc: "Theodore Ts'o" 
Cc: Alexander Viro 
Cc: Andreas Dilger 
Cc: Dave Chinner 
Cc: Ingo Molnar 
Cc: Jan Kara 
Cc: Jeff Layton 
Cc: Matthew Wilcox 
Cc: Thomas Gleixner 
Cc: Dan Williams 
Cc: Matthew Wilcox 
Cc: Dave Hansen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds