Recently I've been seeing xfs/051 fail on 1k block size filesystems.
Trying to trace the events during the test lead to the problem going
away, indicating that it was a race condition that lead to this
ASSERT failure:

XFS: Assertion failed: atomic_read(&pag->pag_ref) == 0, file: fs/xfs/xfs_mount.c, line: 156
.....
[<ffffffff814e1257>] xfs_free_perag+0x87/0xb0
[<ffffffff814e21b9>] xfs_mountfs+0x4d9/0x900
[<ffffffff814e5dff>] xfs_fs_fill_super+0x3bf/0x4d0
[<ffffffff811d8800>] mount_bdev+0x180/0x1b0
[<ffffffff814e3ff5>] xfs_fs_mount+0x15/0x20
[<ffffffff811d90a8>] mount_fs+0x38/0x170
[<ffffffff811f4347>] vfs_kern_mount+0x67/0x120
[<ffffffff811f7018>] do_mount+0x218/0xd60
[<ffffffff811f7e5b>] SyS_mount+0x8b/0xd0

When I finally caught it with tracing enabled, I saw that AG 2 had
an elevated reference count and a buffer was responsible for it. I
tracked down the specific buffer, and found that it was missing the
final reference count release that would put it back on the LRU and
hence be found by xfs_wait_buftarg() calls in the log mount failure
handling.

The last four traces for the buffer before the assert were (trimmed
for relevance)

kworker/0:1-5259   xfs_buf_iodone:        hold 2  lock 0 flags ASYNC
kworker/0:1-5259   xfs_buf_ioerror:       hold 2  lock 0 error -5
mount-7163	   xfs_buf_lock_done:     hold 2  lock 0 flags ASYNC
mount-7163	   xfs_buf_unlock:        hold 2  lock 1 flags ASYNC

This is an async write that is completing, so there's nobody waiting
for it directly.  Hence we call xfs_buf_relse() once all the
processing is complete. That does:

static inline void xfs_buf_relse(xfs_buf_t *bp)
{
	xfs_buf_unlock(bp);
	xfs_buf_rele(bp);
}

Now, it's clear that mount is waiting on the buffer lock, and that
it has been released by xfs_buf_relse() and gained by mount. This is
expected, because at this point the mount process is in
xfs_buf_delwri_submit() waiting for all the IO it submitted to
complete.

The mount process, however, is waiting on the lock for the buffer
because it is in xfs_buf_delwri_submit(). This waits for IO
completion, but it doesn't wait for the buffer reference owned by
the IO to go away. The mount process collects all the completions,
fails the log recovery, and the higher level code then calls
xfs_wait_buftarg() to free all the remaining buffers in the
filesystem.

The issue is that on unlocking the buffer, the scheduler has decided
that the mount process has higher priority than the the kworker
thread that is running the IO completion, and so immediately
switched contexts to the mount process from the semaphore unlock
code, hence preventing the kworker thread from finishing the IO
completion and releasing the IO reference to the buffer.

Hence by the time that xfs_wait_buftarg() is run, the buffer still
has an active reference and so isn't on the LRU list that the
function walks to free the remaining buffers. Hence we miss that
buffer and continue onwards to tear down the mount structures,
at which time we get find a stray reference count on the perag
structure. On a non-debug kernel, this will be ignored and the
structure torn down and freed. Hence when the kworker thread is then
rescheduled and the buffer released and freed, it will access a
freed perag structure.

The problem here is that when the log mount fails, we still need to
quiesce the log to ensure that the IO workqueues have returned to
idle before we run xfs_wait_buftarg(). By synchronising the
workqueues, we ensure that all IO completions are fully processed,
not just to the point where buffers have been unlocked. This ensures
we don't end up in the situation above.

cc: <stable@vger.kernel.org> # 3.18
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

This reverts commit 24ba16bb as it
prevents machines from suspending. This regression occurs when the
xfsaild is idle on entry to suspend, and so there s no activity to
wake it from it's idle sleep and hence see that it is supposed to
freeze. Hence the freezer times out waiting for it and suspend is
cancelled.

There is no obvious fix for this short of freezing the filesystem
properly, so revert this change for now.

cc: <stable@vger.kernel.org> # 4.4
Signed-off-by: Dave Chinner <david@fromorbit.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

When we do dquot readahead in log recovery, we do not use a verifier
as the underlying buffer may not have dquots in it. e.g. the
allocation operation hasn't yet been replayed. Hence we do not want
to fail recovery because we detect an operation to be replayed has
not been run yet. This problem was addressed for inodes in commit
d8914002 ("xfs: inode buffers may not be valid during recovery
readahead") but the problem was not recognised to exist for dquots
and their buffers as the dquot readahead did not have a verifier.

The result of not using a verifier is that when the buffer is then
next read to replay a dquot modification, the dquot buffer verifier
will only be attached to the buffer if *readahead is not complete*.
Hence we can read the buffer, replay the dquot changes and then add
it to the delwri submission list without it having a verifier
attached to it. This then generates warnings in xfs_buf_ioapply(),
which catches and warns about this case.

Fix this and make it handle the same readahead verifier error cases
as for inode buffers by adding a new readahead verifier that has a
write operation as well as a read operation that marks the buffer as
not done if any corruption is detected.  Also make sure we don't run
readahead if the dquot buffer has been marked as cancelled by
recovery.

This will result in readahead either succeeding and the buffer
having a valid write verifier, or readahead failing and the buffer
state requiring the subsequent read to resubmit the IO with the new
verifier.  In either case, this will result in the buffer always
ending up with a valid write verifier on it.

Note: we also need to fix the inode buffer readahead error handling
to mark the buffer with EIO. Brian noticed the code I copied from
there wrong during review, so fix it at the same time. Add comments
linking the two functions that handle readahead verifier errors
together so we don't forget this behavioural link in future.

cc: <stable@vger.kernel.org> # 3.12 - current
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

When we do inode readahead in log recovery, we do can do the
readahead before we've replayed the icreate transaction that stamps
the buffer with inode cores. The inode readahead verifier catches
this and marks the buffer as !done to indicate that it doesn't yet
contain valid inodes.

In adding buffer error notification  (i.e. setting b_error = -EIO at
the same time as as we clear the done flag) to such a readahead
verifier failure, we can then get subsequent inode recovery failing
with this error:

XFS (dm-0): metadata I/O error: block 0xa00060 ("xlog_recover_do..(read#2)") error 5 numblks 32

This occurs when readahead completion races with icreate item replay
such as:

	inode readahead
		find buffer
		lock buffer
		submit RA io
	....
	icreate recovery
	    xfs_trans_get_buffer
		find buffer
		lock buffer
		<blocks on RA completion>
	.....
	<ra completion>
		fails verifier
		clear XBF_DONE
		set bp->b_error = -EIO
		release and unlock buffer
	<icreate gains lock>
	icreate initialises buffer
	marks buffer as done
	adds buffer to delayed write queue
	releases buffer

At this point, we have an initialised inode buffer that is up to
date but has an -EIO state registered against it. When we finally
get to recovering an inode in that buffer:

	inode item recovery
	    xfs_trans_read_buffer
		find buffer
		lock buffer
		sees XBF_DONE is set, returns buffer
	    sees bp->b_error is set
		fail log recovery!

Essentially, we need xfs_trans_get_buf_map() to clear the error status of
the buffer when doing a lookup. This function returns uninitialised
buffers, so the buffer returned can not be in an error state and
none of the code that uses this function expects b_error to be set
on return. Indeed, there is an ASSERT(!bp->b_error); in the
transaction case in xfs_trans_get_buf_map() that would have caught
this if log recovery used transactions....

This patch firstly changes the inode readahead failure to set -EIO
on the buffer, and secondly changes xfs_buf_get_map() to never
return a buffer with an error state set so this first change doesn't
cause unexpected log recovery failures.

cc: <stable@vger.kernel.org> # 3.12 - current
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Calls to xfs_bmap_finish() and xfs_trans_ijoin(), and the
associated comments were replicated several times across
the attribute code, all dealing with what to do if the
transaction was or wasn't committed.

And in that replicated code, an ASSERT() test of an
uninitialized variable occurs in several locations:

	error = xfs_attr_thing(&args);
	if (!error) {
		error = xfs_bmap_finish(&args.trans, args.flist,
					&committed);
	}
	if (error) {
		ASSERT(committed);

If the first xfs_attr_thing() failed, we'd skip the xfs_bmap_finish,
never set "committed", and then test it in the ASSERT.

Fix this up by moving the committed state internal to xfs_bmap_finish,
and add a new inode argument.  If an inode is passed in, it is passed
through to __xfs_trans_roll() and joined to the transaction there if
the transaction was committed.

xfs_qm_dqalloc() was a little unique in that it called bjoin rather
than ijoin, but as Dave points out we can detect the committed state
but checking whether (*tpp != tp).

Addresses-Coverity-Id: 102360
Addresses-Coverity-Id: 102361
Addresses-Coverity-Id: 102363
Addresses-Coverity-Id: 102364
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

For large sparse or fragmented files, checking every single entry in
the bmapbt on every operation is prohibitively expensive. Especially
as such checks rarely discover problems during normal operations on
high extent coutn files. Our regression tests don't tend to exercise
files with hundreds of thousands to millions of extents, so mostly
this isn't noticed.

However, trying to run things like xfs_mdrestore of large filesystem
dumps on a debug kernel quickly becomes impossible as the CPU is
completely burnt up repeatedly walking the sparse file bmapbt that
is generated for every allocation that is made.

Hence, if the file has more than 10,000 extents, just don't bother
with walking the tree to check it exhaustively. The btree code has
checks that ensure that the newly inserted/removed/modified record
is correctly ordered, so the entrie tree walk in thses cases has
limited additional value.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

This allows us to see page cache driven readahead in action as it
passes through XFS. This helps to understand buffered read
throughput problems such as readahead IO IO sizes being too small
for the underlying device to reach max throughput.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

XFS now uses CRC verification over a limited section of the log to
detect torn writes prior to a crash. This is difficult to test directly
due to the timing and hardware requirements to cause a short write.

Add a mechanism to inject CRC errors into log records to facilitate
testing torn write detection during log recovery. This mechanism is
dangerous and can result in filesystem corruption. Thus, it is only
available in DEBUG mode for testing/development purposes. Set a non-zero
value to the following sysfs entry to enable error injection:

	/sys/fs/xfs/<dev>/log/log_badcrc_factor

Once enabled, XFS intentionally writes an invalid CRC to a log record at
some random point in the future based on the provided frequency. The
filesystem immediately shuts down once the record has been written to
the physical log to prevent metadata writeback (e.g., AIL insertion)
once the log write completes. This helps reasonably simulate a torn
write to the log as the affected record must be safe to discard. The
next mount after the intentional shutdown requires log recovery and
should detect and recover from the torn write.

Note again that this _will_ result in data loss or worse. For testing
and development purposes only!
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Certain types of storage, such as persistent memory, do not provide
sector atomicity for writes. This means that if a crash occurs while XFS
is writing log records, only part of those records might make it to the
storage. This is problematic because log recovery uses the cycle value
packed at the top of each log block to locate the head/tail of the log.
This can lead to CRC verification failures during log recovery and an
unmountable fs for a filesystem that is otherwise consistent.

Update log recovery to incorporate log record CRC verification as part
of the head/tail discovery process. Once the head is located via the
traditional algorithm, run a CRC-only pass over the records up to the
head of the log. If CRC verification fails, assume that the records are
torn as a matter of policy and trim the head block back to the start of
the first bad record.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Rather than just being able to turn DAX on and off via a mount
option, some applications may only want to enable DAX for certain
performance critical files in a filesystem.

This patch introduces a new inode flag to enable DAX in the v3 inode
di_flags2 field. It adds support for setting and clearing flags in
the di_flags2 field via the XFS_IOC_FSSETXATTR ioctl, and sets the
S_DAX inode flag appropriately when it is seen.

When this flag is set on a directory, it acts as an "inherit flag".
That is, inodes created in the directory will automatically inherit
the on-disk inode DAX flag, enabling administrators to set up
directory heirarchies that automatically use DAX. Setting this flag
on an empty root directory will make the entire filesystem use DAX
by default.
Signed-off-by: Dave Chinner <dchinner@redhat.com>

Now that the ioctls have been hoisted up to the VFS level, use
the VFs definitions directly and remove the XFS specific definitions
completely. Userspace is going to have to handle the change of this
interface separately, so removing the definitions from xfs_fs.h is
not an issue here at all.
Signed-off-by: Dave Chinner <dchinner@redhat.com>

Hoist the ioctl definitions for the XFS_IOC_FS[SG]SETXATTR API from
fs/xfs/libxfs/xfs_fs.h to include/uapi/linux/fs.h so that the ioctls
can be used by all filesystems, not just XFS. This enables
(initially) ext4 to use the ioctl to set project IDs on inodes.

Based-on-patch-from: Li Xi <lixi@ddn.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>

Doing a splice read (generic/249) generates a lockdep splat because
we recursively lock the inode iolock in this path:

SyS_sendfile64
do_sendfile
do_splice_direct
splice_direct_to_actor
do_splice_to
xfs_file_splice_read			<<<<<< lock here
default_file_splice_read
vfs_readv
do_readv_writev
do_iter_readv_writev
xfs_file_read_iter			<<<<<< then here

The issue here is that for DAX inodes we need to avoid the page
cache path and hence simply push it into the normal read path.
Unfortunately, we can't tell down at xfs_file_read_iter() whether we
are being called from the splice path and hence we cannot avoid the
locking at this layer. Hence we simply have to drop the inode
locking at the higher splice layer for DAX.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Commit 1ca19157 ("xfs: Don't use unwritten extents for DAX") enabled
the DAX allocation call to dip into the reserve pool in case it was
converting unwritten extents rather than allocating blocks. This was
a direct copy of the unwritten extent conversion code, but had an
unintended side effect of allowing normal data block allocation to
use the reserve pool. Hence normal block allocation could deplete
the reserve pool and prevent unwritten extent conversion at ENOSPC,
hence violating fallocate guarantees on preallocated space.

Fix it by checking whether the incoming map from __xfs_get_blocks()
spans an unwritten extent and only use the reserve pool if the
allocation covers an unwritten extent.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

The return type "unsigned long" was used by the suffix_kstrtoint()
function even though it will eventually return a negative error code.
Improve this implementation detail by using the type "int" instead.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Create xfs_btree_sblock_verify() to verify short-format btree blocks
(i.e. the per-AG btrees with 32-bit block pointers) instead of
open-coding them.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Because struct xfs_agfl is 36 bytes long and has a 64-bit integer
inside it, gcc will quietly round the structure size up to the nearest
64 bits -- in this case, 40 bytes.  This results in the XFS_AGFL_SIZE
macro returning incorrect results for v5 filesystems on 64-bit
machines (118 items instead of 119).  As a result, a 32-bit xfs_repair
will see garbage in AGFL item 119 and complain.

Therefore, tell gcc not to pad the structure so that the AGFL size
calculation is correct.

cc: <stable@vger.kernel.org> # 3.10 - 4.4
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Use a convenience variable instead of open-coding the inode fork.
This isn't really needed for now, but will become important when we
add the copy-on-write fork later.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Update the log ticket reservation type printing code to reflect
all the types of log tickets, to avoid incorrect debug output and
avoid running off the end of the array.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Since xfs_repair wants to use xfs_alloc_fix_freelist, remove the
static designation.  xfsprogs already has this; this simply brings
the kernel up to date.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

There are no callers of the xfs_buf_ioend_async() function outside
of the fs/xfs/xfs_buf.c. So, let's make it static.
Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Linux's quota subsystem has an ability to handle project quota. This
commit just utilizes the ability from xfs side.  dbus-monitor and
quota_nld shipped as part of quota-tools can be used for testing.
See the patch posting on the XFS list for details on testing.
Signed-off-by: Masatake YAMATO <yamato@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

In my earlier commit

  c29aad41 xfs: pass mp to XFS_WANT_CORRUPTED_GOTO

I added some local mp variables with code which indicates that
mp might be NULL.  Coverity doesn't like this now, because the
updated per-fs XFS_STATS macros dereference mp.

I don't think this is actually a problem; from what I can tell,
we cannot get to these functions with a null bma->tp, so my NULL
check was probably pointless.  Still, it's not super obvious.

So switch this code to get mp from the inode on the xfs_bmalloca
structure, with no conditional, because the functions are already
using bmap->ip directly.

Addresses-Coverity-Id: 1339552
Addresses-Coverity-Id: 1339553
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

This adds a name to each buf_ops structure, so that if
a verifier fails we can print the type of verifier that
failed it.  Should be a slight debugging aid, I hope.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

If there is any non zero bit in a long bitmap, it can jump out of the
loop and finish the function as soon as possible.
Signed-off-by: Jia He <hejianet@gmail.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

As part of the head/tail discovery process, log recovery locates the
head block and then reverse seeks to find the start of the last active
record in the log. This is non-trivial as the record itself could have
wrapped around the end of the physical log. Log recovery torn write
detection potentially needs to walk further behind the last record in
the log, as multiple log I/Os can be in-flight at one time during a
crash event.

Therefore, refactor the reverse log record header search mechanism into
a new helper that supports the ability to seek past an arbitrary number
of log records (or until the tail is hit). Update the head/tail search
mechanism to call the new helper, but otherwise there is no change in
log recovery behavior.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Log recovery torn write detection uses CRC verification over a range of
the active log to identify torn writes. Since the generic log recovery
pass code implements a superset of the functionality required for CRC
verification, it can be easily modified to support a CRC verification
only pass.

Create a new CRC pass type and update the log record processing helper
to skip everything beyond CRC verification when in this mode. This pass
will be invoked in subsequent patches to implement torn write detection.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Each log recovery pass walks from the tail block to the head block and
processes records appropriately based on the associated log pass type.
There are various failure conditions that can occur through this
sequence, such as I/O errors, CRC errors, etc. Log torn write detection
will perform CRC verification near the head of the log to detect torn
writes and trim torn records from the log appropriately.

As it is, xlog_do_recovery_pass() only returns an error code in the
event of CRC failure, which isn't enough information to trim the head of
the log. Update xlog_do_recovery_pass() to optionally return the start
block of the associated record when an error occurs. This patch contains
no functional changes.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Log record CRC verification currently occurs during active log recovery,
immediately before a log record is unpacked. Therefore, the CRC
calculation code is buried within the data unpack function. CRC
verification pass support only needs to go so far as check the CRC, but
this is not easily allowed as the code is currently organized.

Since we now have a new log record processing helper, pull the record
CRC verification code out from the unpack helper and open-code it at the
top of the new process helper. This facilitates the ability to modify
how records are processed based on the type of the current pass. This
patch contains no functional changes.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

xlog_do_recovery_pass() duplicates a couple function calls related to
processing log records because the function must handle wrapping around
the end of the log if the head is behind the tail. This is implemented
as separate loops. CRC verification pass support will modify how records
are processed in both of these loops.

Rather than continue to duplicate code, factor the calls that process a
log record into a new helper and call that helper from both loops. This
patch contains no functional changes.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

XFS log records have separate fields for the record size and the iclog
size used to write the record. mkfs.xfs zeroes the log and writes an
unmount record to generate a clean log for the subsequent mount. The
userspace record logging code has a bug where the iclog size (h_size)
field of the log record is hardcoded to 32k, even if a log stripe unit
is specified. The log record length is correctly extended to the stripe
unit. Since the kernel log recovery code uses the h_size field to
determine the log buffer size, this means that the kernel can attempt to
read/process records larger than the buffer size and overrun the buffer.

This has historically not been a problem because the kernel doesn't
actually run through log recovery in the clean unmount case. Instead,
the kernel detects that a single unmount record exists between the head
and tail and pushes the tail forward such that the log is viewed as
clean (head == tail). Once CRC verification is enabled, however, all
records at the head of the log are verified for CRC errors and thus we
are susceptible to overrun problems if the iclog field is not correct.

While the core problem must be fixed in userspace, this is historical
behavior that must be detected in the kernel to avoid severe side
effects such as memory corruption and crashes. Update the log buffer
size calculation code to detect this condition, warn the user and resize
the log buffer based on the log stripe unit. Return a corruption error
in cases where this does not look like a clean filesystem (i.e., the log
record header indicates more than one operation).
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Pull MIPS build fix from Ralf Baechle:
 "Fix a makefile issue resulting in build breakage with older binutils.

  This has sat in -next for a few days, testers and buildbot are happy
  with it, too though if you are going for another -rc that'd certainly
  help ironing out a few more issues"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: VDSO: Fix build error with binutils 2.24 and earlier

Pull i915 drm fixes from Jani Nikula:
 "Two display fixes still for v4.4.

  The new year's resolution is to start using signed tags per Linus'
  request.  This one is still unsigned; I want to fix this up in our
  maintainer scripts instead of doing it one-off"

* tag 'drm-intel-fixes-2016-01-02' of git://anongit.freedesktop.org/drm-intel:
  drm/i915: increase the tries for HDMI hotplug live status checking
  drm/i915: Unbreak check_digital_port_conflicts()

Pull PCI bugfix from Bjorn Helgaas:
 "Here's another fix for v4.4.

  This fixes 32-bit config reads for the HiSilicon driver.  Obviously
  the driver is completely broken without this fix (apparently it
  actually was tested internally, but got broken somehow in the process
  of upstreaming it).

  Summary:

  HiSilicon host bridge driver
    Fix 32-bit config reads (Dongdong Liu)"

* tag 'pci-v4.4-fixes-3' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI: hisi: Fix hisi_pcie_cfg_read() 32-bit reads