Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

This helper doesn't add any real value over just calling iomap_zero_range
directly, so remove it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

i_cnextents does not include delayed allocated extents, so switch
to the inode fork size check that we already use in other places
instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

The extent swap mechanism requires a unique implementation for
rmapbt enabled filesystems. Because the rmapbt tracks extent owner
information, extent swap must individually unmap and remap each
extent between the two inodes.

The rmapbt extent swap transaction block reservation currently
accounts for the worst case bmapbt block and rmapbt block
consumption based on the extent count of each inode. There is a
corner case that exists due to the extent swap implementation that
is not covered by this reservation, however.

If one of the associated inodes is just over the max extent count
used for extent format inodes (i.e., the inode is in btree format by
a single extent), the unmap/remap cycle of the extent swap can
bounce the inode between extent and btree format multiple times,
almost as many times as there are extents in the inode (if the
opposing inode happens to have one less, for example). Each back and
forth cycle involves a block free and allocation, which isn't a
problem except for that the initial transaction reservation must
account for the total number of block allocations performed by the
chain of deferred operations. If not, a block reservation overrun
occurs and the filesystem shuts down.

Update the rmapbt extent swap block reservation to check for this
situation and add some block reservation slop to ensure the entire
operation succeeds. We'd never likely require reservation for both
inodes as fsr wouldn't defrag the file in that case, but the
additional reservation is constrained by the data fork size so be
cautious and check for both.
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

Refactor xfs_lock_two_inodes to take separate locking modes for each
inode.  Specifically, this enables us to take a SHARED lock on one inode
and an EXCL lock on the other.  The lock class (MMAPLOCK/ILOCK) must be
the same for each inode.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

Supporting a small bit of data inside the inode fork blows up the fork size
a lot, removing the 32 bytes of inline data halves the effective size of
the inode fork (and it still has a lot of unused padding left), and the
performance of a single kmalloc doesn't show up compared to the size to read
an inode or create one.

It also simplifies the fork management code a lot.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

Add a new xfs_iext_cursor structure to hide the direct extent map
index manipulations. In addition to the existing lookup/get/insert/
remove and update routines new primitives to get the first and last
extent cursor, as well as moving up and down by one extent are
provided.  Also new are convenience to increment/decrement the
cursor and retreive the new extent, as well as to peek into the
previous/next extent without updating the cursor and last but not
least a macro to iterate over all extents in a fork.

[darrick: rename for_each_iext to for_each_xfs_iext]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

Have a separate helper for insert vs collapse, as this prepares us for
simplifying the code in the next patches.

Also changed the done output argument to a bool intead of int for both
new functions.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

The define was always set to 1, which means looping until we reach is
was dead code from the start.

Also remove an initialization of next_fsb for the done case that doesn't
fit the new code flow - it was never checked by the caller in the done
case to start with.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

The code is sufficiently different for the insert vs collapse cases both
in xfs_shift_file_space itself and the callers that untangling them will
make life a lot easier down the road.

We still keep a common helper for flushing all data and COW state to get
the inode into the right shape for shifting the extents around.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

Instead of passing in a formatter callback allocate the bmap buffer
in the caller and process the entries there.  Additionally replace
the in-kernel buffer with a new much smaller structure, and unify
the implementation of the different ioctls in a single function.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

Currently getbmap uses xfs_bmapi_read to query the extent map, and then
fixes up various bits that are eventually reported to userspace.

This patch instead rewrites it to use xfs_iext_lookup_extent and
xfs_iext_get_extent to iteratively process the extent map.  This not
only avoids the need to allocate a map for the returned xfs_bmbt_irec
structures but also greatly simplified the code.

There are two intentional behavior changes compared to the old code:

 - the current code reports unwritten extents that don't directly border
   a written one as unwritten even when not passing the BMV_IF_PREALLOC
   option, contrary to the documentation.  The new code requires the
   BMV_IF_PREALLOC flag to report the unwrittent extent bit.
 - The new code does never merges consecutive extents, unlike the old
   code that sometimes does it based on the boundaries of the
   xfs_bmapi_read calls.  Note that the extent merging behavior was
   entirely undocumented.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

Various utility functions and interfaces that iterate internal
devices try to reference the realtime device even when RT support is
not compiled into the kernel.

Make sure this code is excluded from the CONFIG_XFS_RT=n build,
and where appropriate stub functions to return fatal errors if
they ever get called when RT support is not present.
Signed-Off-By: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

Since the CoW fork exists as a secondary data structure to the data
fork, we must always swap cow forks during swapext.  We also need to
swap the extent counts and reset the cowblocks tags.
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

When we perform an finsert/fcollapse operation, cancel all the CoW
extents for the affected file offset range so that they don't end up
pointing to the wrong blocks.
Reported-by: NAmir Goldstein <amir73il@gmail.com>
Reviewed-by: NCarlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

This avoids poking into the internals of the extent list.  Also return
the number of extents as the return value instead of an additional
by reference argument, and make it available to callers outside of
xfs_bmap_util.c
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

The owner change bmbt scan that occurs during extent swap operations
does not handle ordered buffer failures. Buffers that cannot be
marked ordered must be physically logged so previously dirty ranges
of the buffer can be relogged in the transaction.

Since the bmbt scan may need to process and potentially log a large
number of blocks, we can't expect to complete this operation in a
single transaction. Update extent swap to use a permanent
transaction with enough log reservation to physically log a buffer.
Update the bmbt scan to physically log any buffers that cannot be
ordered and to terminate the scan with -EAGAIN. On -EAGAIN, the
caller rolls the transaction and restarts the scan. Finally, update
the bmbt scan helper function to skip bmbt blocks that already match
the expected owner so they are not reprocessed after scan restarts.
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
[darrick: fix the xfs_trans_roll call]
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

The extent swap operation currently resets bmbt block owners before
the inode forks are swapped. The bmbt buffers are marked as ordered
so they do not have to be physically logged in the transaction.

This use of ordered buffers is not safe as bmbt buffers may have
been previously physically logged. The bmbt owner change algorithm
needs to be updated to physically log buffers that are already dirty
when/if they are encountered. This means that an extent swap will
eventually require multiple rolling transactions to handle large
btrees. In addition, all inode related changes must be logged before
the bmbt owner change scan begins and can roll the transaction for
the first time to preserve fs consistency via log recovery.

In preparation for such fixes to the bmbt owner change algorithm,
refactor the bmbt scan out of the extent fork swap code to the last
operation before the transaction is committed. Update
xfs_swap_extent_forks() to only set the inode log flags when an
owner change scan is necessary. Update xfs_swap_extents() to trigger
the owner change based on the inode log flags. Note that since the
owner change now occurs after the extent fork swap, the inode btrees
must be fixed up with the inode number of the current inode (similar
to log recovery).
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

And instead require callers to explicitly join the inode using
xfs_defer_ijoin.  Also consolidate the defer error handling in
a few places using a goto label.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

Refactor the inode fork block counting function to count extents for us
at the same time.  This will be used by the bmbt scrubber function.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

There is an inconsistency in the way that _bmap_count_blocks deals with
delalloc reservations -- if the specified fork is in extents format,
*count is set to the total number of blocks referenced by the in-core
fork, including delalloc extents.  However, if the fork is in btree
format, *count is set to the number of blocks referenced by the on-disk
fork, which does /not/ include delalloc extents.

For the lone existing caller of _bmap_count_blocks this hasn't been an
issue because the function is only used to count xattr fork blocks
(where there aren't any delalloc reservations).  However, when scrub
comes along it will use this same function to check di_nblocks against
both on-disk extent maps, so we need this behavior to be consistent.

Therefore, fix _bmap_count_leaves not to include delalloc extents and
remove unnecessary parameters.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

Adapt _reflink_find_shared to take an optional transaction pointer.  The
inode scrubber code will need to decide (within transaction context) if
a file has shared blocks.  To avoid buffer deadlocks, we must pass the
tp through to this function's utility calls.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

This is a purely mechanical patch that removes the private
__{u,}int{8,16,32,64}_t typedefs in favor of using the system
{u,}int{8,16,32,64}_t typedefs.  This is the sed script used to perform
the transformation and fix the resulting whitespace and indentation
errors:

s/typedef\t__uint8_t/typedef __uint8_t\t/g
s/typedef\t__uint/typedef __uint/g
s/typedef\t__int\([0-9]*\)_t/typedef int\1_t\t/g
s/__uint8_t\t/__uint8_t\t\t/g
s/__uint/uint/g
s/__int\([0-9]*\)_t\t/__int\1_t\t\t/g
s/__int/int/g
/^typedef.*int[0-9]*_t;$/d
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

gcc-7 flags the use of integer math inside of a condition
as a potential bug:

fs/xfs/xfs_bmap_util.c: In function 'xfs_swap_extents_check_format':
fs/xfs/xfs_bmap_util.c:1619:8: error: '<<' in boolean context, did you mean '<' ? [-Werror=int-in-bool-context]
fs/xfs/xfs_bmap_util.c:1629:8: error: '<<' in boolean context, did you mean '<' ? [-Werror=int-in-bool-context]

There is already a helper function for testing the di_forkoff
field for zero, so let's use that instead to shut up the warning.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

By run fsstress long enough time enough in RHEL-7, I find an
assertion failure (harder to reproduce on linux-4.11, but problem
is still there):

  XFS: Assertion failed: (iflags & BMV_IF_DELALLOC) != 0, file: fs/xfs/xfs_bmap_util.c

The assertion is in xfs_getbmap() funciton:

  if (map[i].br_startblock == DELAYSTARTBLOCK &&
-->   map[i].br_startoff <= XFS_B_TO_FSB(mp, XFS_ISIZE(ip)))
          ASSERT((iflags & BMV_IF_DELALLOC) != 0);

When map[i].br_startoff == XFS_B_TO_FSB(mp, XFS_ISIZE(ip)), the
startoff is just at EOF. But we only need to make sure delalloc
extents that are within EOF, not include EOF.
Signed-off-by: NZorro Lang <zlang@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

When we're fulfilling a BMAPX request, jump out early if the data fork
is in local format.  This prevents us from hitting a debugging check in
bmapi_read and barfing errors back to userspace.  The on-disk extent
count check later isn't sufficient for IF_DELALLOC mode because da
extents are in memory and not on disk.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

On some architectures do_div does the pointer compare
trick to make sure that we've sent it an unsigned 64-bit
number.  (Why unsigned?  I don't know.)

Fix up the few places that squawk about this; in
xfs_bmap_wants_extents() we just used a bare int64_t so change
that to unsigned.

In xfs_adjust_extent_unmap_boundaries() all we wanted was the
mod, and we have an xfs-specific function to handle that w/o
side effects, which includes proper casting for do_div.

In xfs_daddr_to_ag[b]no, we were using the wrong type anyway;
XFS_BB_TO_FSBT returns a block in the filesystem, so use
xfs_rfsblock_t not xfs_daddr_t, and gain the unsignedness
from that type as a bonus.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

Lockdep complains about use of the iolock in inode reclaim context
because it doesn't understand that reclaim has the last reference to
the inode, and thus an iolock->reclaim->iolock deadlock is not
possible.

The iolock is technically not necessary in xfs_inactive() and was
only added to appease an assert in xfs_free_eofblocks(), which can
be called from other non-reclaim contexts. Therefore, just kill the
assert and drop the use of the iolock from reclaim context to quiet
lockdep.
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

Turn the existing discard flag into a new BLKDEV_ZERO_UNMAP flag with
similar semantics, but without referring to diѕcard.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

This checks for all the non-normal extent types, including handling both
encodings of delayed allocations.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

When punching past EOF on XFS, fallocate(mode=PUNCH_HOLE|KEEP_SIZE) will
round the file size up to the nearest multiple of PAGE_SIZE:

  calvinow@vm-disks/generic-xfs-1 ~$ dd if=/dev/urandom of=test bs=2048 count=1
  calvinow@vm-disks/generic-xfs-1 ~$ stat test
    Size: 2048            Blocks: 8          IO Block: 4096   regular file
  calvinow@vm-disks/generic-xfs-1 ~$ fallocate -n -l 2048 -o 2048 -p test
  calvinow@vm-disks/generic-xfs-1 ~$ stat test
    Size: 4096            Blocks: 8          IO Block: 4096   regular file

Commit 3c2bdc91 ("xfs: kill xfs_zero_remaining_bytes") replaced
xfs_zero_remaining_bytes() with calls to iomap helpers. The new helpers
don't enforce that [pos,offset) lies strictly on [0,i_size) when being
called from xfs_free_file_space(), so by "leaking" these ranges into
xfs_zero_range() we get this buggy behavior.

Fix this by reintroducing the checks xfs_zero_remaining_bytes() did
against i_size at the bottom of xfs_free_file_space().
Reported-by: NAaron Gao <gzh@fb.com>
Fixes: 3c2bdc91 ("xfs: kill xfs_zero_remaining_bytes")
Cc: Christoph Hellwig <hch@lst.de>
Cc: Brian Foster <bfoster@redhat.com>
Cc: <stable@vger.kernel.org> # 4.8+
Signed-off-by: NCalvin Owens <calvinowens@fb.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

When punching past EOF on XFS, fallocate(mode=PUNCH_HOLE|KEEP_SIZE) will
round the file size up to the nearest multiple of PAGE_SIZE:

  calvinow@vm-disks/generic-xfs-1 ~$ dd if=/dev/urandom of=test bs=2048 count=1
  calvinow@vm-disks/generic-xfs-1 ~$ stat test
    Size: 2048            Blocks: 8          IO Block: 4096   regular file
  calvinow@vm-disks/generic-xfs-1 ~$ fallocate -n -l 2048 -o 2048 -p test
  calvinow@vm-disks/generic-xfs-1 ~$ stat test
    Size: 4096            Blocks: 8          IO Block: 4096   regular file

Commit 3c2bdc91 ("xfs: kill xfs_zero_remaining_bytes") replaced
xfs_zero_remaining_bytes() with calls to iomap helpers. The new helpers
don't enforce that [pos,offset) lies strictly on [0,i_size) when being
called from xfs_free_file_space(), so by "leaking" these ranges into
xfs_zero_range() we get this buggy behavior.

Fix this by reintroducing the checks xfs_zero_remaining_bytes() did
against i_size at the bottom of xfs_free_file_space().
Reported-by: NAaron Gao <gzh@fb.com>
Fixes: 3c2bdc91 ("xfs: kill xfs_zero_remaining_bytes")
Cc: Christoph Hellwig <hch@lst.de>
Cc: Brian Foster <bfoster@redhat.com>
Cc: <stable@vger.kernel.org> # 4.8+
Signed-off-by: NCalvin Owens <calvinowens@fb.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

We can deduce the allocation type from the bno argument, and do the
return without prod much simpler internally.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
[darrick: fix the macro for the non-rt build]
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

The block reservation for the transaction allocated in
xfs_shift_file_space() is an artifact of the original collapse range
support. It exists to handle the case where a collapse range occurs,
the initial extent is left shifted into a location that forms a
contiguous boundary with the previous extent and thus the extents
are merged. This code was subsequently refactored and reused for
insert range (right shift) support.

If an insert range occurs under low free space conditions, the
extent at the starting offset is split before the first shift
transaction is allocated. If the block reservation fails, this
leaves separate, but contiguous extents around in the inode. While
not a fatal problem, this is unexpected and will flag a warning on
subsequent insert range operations on the inode. This problem has
been reproduce intermittently by generic/270 running against a
ramdisk device.

Since right shift does not create new extent boundaries in the
inode, a block reservation for extent merge is unnecessary. Update
xfs_shift_file_space() to conditionally reserve fs blocks for left
shift transactions only. This avoids the warning reproduced by
generic/270.
Reported-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

The "full" argument was used only by the fiemap formatter,
which is now gone with the iomap updates.

Remove the unused arg.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Reviewed-by: NAlex Elder <elder@linaro.org>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

It's possible for post-eof blocks to end up being used for direct I/O
writes. dio write performs an upfront unwritten extent allocation, sends
the dio and then updates the inode size (if necessary) on write
completion. If a file release occurs while a file extending dio write is
in flight, it is possible to mistake the post-eof blocks for speculative
preallocation and incorrectly truncate them from the inode. This means
that the resulting dio write completion can discover a hole and allocate
new blocks rather than perform unwritten extent conversion.

This requires a strange mix of I/O and is thus not likely to reproduce
in real world workloads. It is intermittently reproduced by generic/299.
The error manifests as an assert failure due to transaction overrun
because the aforementioned write completion transaction has only
reserved enough blocks for btree operations:

  XFS: Assertion failed: tp->t_blk_res_used <= tp->t_blk_res, \
   file: fs/xfs//xfs_trans.c, line: 309

The root cause is that xfs_free_eofblocks() uses i_size to truncate
post-eof blocks from the inode, but async, file extending direct writes
do not update i_size until write completion, long after inode locks are
dropped. Therefore, xfs_free_eofblocks() effectively truncates the inode
to the incorrect size.

Update xfs_free_eofblocks() to serialize against dio similar to how
extending writes are serialized against i_size updates before post-eof
block zeroing. Specifically, wait on dio while under the iolock. This
ensures that dio write completions have updated i_size before post-eof
blocks are processed.
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

xfs_free_eofblocks() requires the IOLOCK_EXCL lock, but is called from
different contexts where the lock may or may not be held. The
need_iolock parameter exists for this reason, to indicate whether
xfs_free_eofblocks() must acquire the iolock itself before it can
proceed.

This is ugly and confusing. Simplify the semantics of
xfs_free_eofblocks() to require the caller to acquire the iolock
appropriately and kill the need_iolock parameter. While here, the mp
param can be removed as well as the xfs_mount is accessible from the
xfs_inode structure. This patch does not change behavior.
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

In a bmapx call, bmv_count is the total size of the array, including the
zeroth element that userspace uses to supply the search key.  The output
array starts at offset 1 so that we can set up the user for the next
invocation.  Since we now can split an extent into multiple bmap records
due to shared/unshared status, we have to be careful that we don't
overflow the output array.

In the original patch f86f4037 ("xfs: teach get_bmapx about shared
extents and the CoW fork") I used cur_ext (the output index) to check
for overflows, albeit with an off-by-one error.  Since nexleft no longer
describes the number of unfilled slots in the output, we can rip all
that out and use cur_ext for the overflow check directly.

Failure to do this causes heap corruption in bmapx callers such as
xfs_io and xfs_scrub.  xfs/328 can reproduce this problem.
Reviewed-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

This patch drops the XFS-own i_iolock and uses the VFS i_rwsem which
recently replaced i_mutex instead.  This means we only have to take
one lock instead of two in many fast path operations, and we can
also shrink the xfs_inode structure.  Thanks to the xfs_ilock family
there is very little churn, the only thing of note is that we need
to switch to use the lock_two_directory helper for taking the i_rwsem
on two inodes in a few places to make sure our lock order matches
the one used in the VFS.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Tested-by: NJens Axboe <axboe@fb.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>