Remove current_pid(), current_test_flags() and
current_clear_flags_nested(), because they are useless.
Signed-off-by: NYafang Shao <laoar.shao@gmail.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>

The page faultround path ->map_pages is implemented in XFS via
filemap_map_pages(). This function checks that pages found in page
cache lookups have not raced with truncate based invalidation by
checking page->mapping is correct and page->index is within EOF.

However, we've known for a long time that this is not sufficient to
protect against races with invalidations done by operations that do
not change EOF. e.g. hole punching and other fallocate() based
direct extent manipulations. The way we protect against these
races is we wrap the page fault operations in a XFS_MMAPLOCK_SHARED
lock so they serialise against fallocate and truncate before calling
into the filemap function that processes the fault.

Do the same for XFS's ->map_pages implementation to close this
potential data corruption issue.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NAmir Goldstein <amir73il@gmail.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>

Move the double-inode locking helpers to xfs_inode.c since they're not
specific to reflink.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

Refactor the two functions that we use to lock and unlock two inodes to
block userspace from initiating IO against a file, whether via system
calls or mmap activity.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

Fix the return value of xfs_reflink_remap_prep so that its return value
conventions match the rest of xfs.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

If the source and destination map are identical, we can skip the remap
step to save some time.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

When logging quota block count updates during a reflink operation, we
only log the /delta/ of the block count changes to the dquot.  Since we
now know ahead of time the extent type of both dmap and smap (and that
they have the same length), we know that we only need to reserve quota
blocks for dmap's blockcount if we're mapping it into a hole.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

Now that we've reworked xfs_reflink_remap_extent to remap only one
extent per transaction, we actually know if the extent being removed is
an allocated mapping.  This means that we now know ahead of time if
we're going to be touching the data fork.

Since we only need blocks for a bmbt split if we're going to update the
data fork, we only need to get quota reservation if we know we're going
to touch the data fork.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

The existing reflink remapping loop has some structural problems that
need addressing:

The biggest problem is that we create one transaction for each extent in
the source file without accounting for the number of mappings there are
for the same range in the destination file.  In other words, we don't
know the number of remap operations that will be necessary and we
therefore cannot guess the block reservation required.  On highly
fragmented filesystems (e.g. ones with active dedupe) we guess wrong,
run out of block reservation, and fail.

The second problem is that we don't actually use the bmap intents to
their full potential -- instead of calling bunmapi directly and having
to deal with its backwards operation, we could call the deferred ops
xfs_bmap_unmap_extent and xfs_refcount_decrease_extent instead.  This
makes the frontend loop much simpler.

Solve all of these problems by refactoring the remapping loops so that
we only perform one remapping operation per transaction, and each
operation only tries to remap a single extent from source to dest.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reported-by: NEdwin Török <edwin@etorok.net>
Tested-by: NEdwin Török <edwin@etorok.net>

The name of this predicate is a little misleading -- it decides if the
extent mapping is allocated and written.  Change the name to be more
direct, as we're going to add a new predicate in the next patch.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

Quota reservations are supposed to account for the blocks that might be
allocated due to a bmap btree split.  Reflink doesn't do this, so fix
this to make the quota accounting more accurate before we start
rearranging things.

Fixes: 862bb360 ("xfs: reflink extents from one file to another")
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

The data fork scrubber calls filemap_write_and_wait to flush dirty pages
and delalloc reservations out to disk prior to checking the data fork's
extent mappings.  Unfortunately, this means that scrub can consume the
EIO/ENOSPC errors that would otherwise have stayed around in the address
space until (we hope) the writer application calls fsync to persist data
and collect errors.  The end result is that programs that wrote to a
file might never see the error code and proceed as if nothing were
wrong.

xfs_scrub is not in a position to notify file writers about the
writeback failure, and it's only here to check metadata, not file
contents.  Therefore, if writeback fails, we should stuff the error code
back into the address space so that an fsync by the writer application
can pick that up.

Fixes: 99d9d8d0 ("xfs: scrub inode block mappings")
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

The rmapbt extent swap algorithm remaps individual extents between
the source inode and the target to trigger reverse mapping metadata
updates. If either inode straddles a format or other bmap allocation
boundary, the individual unmap and map cycles can trigger repeated
bmap block allocations and frees as the extent count bounces back
and forth across the boundary. While net block usage is bound across
the swap operation, this behavior can prematurely exhaust the
transaction block reservation because it continuously drains as the
transaction rolls. Each allocation accounts against the reservation
and each free returns to global free space on transaction roll.

The previous workaround to this problem attempted to detect this
boundary condition and provide surplus block reservation to
acommodate it. This is insufficient because more remaps can occur
than implied by the extent counts; if start offset boundaries are
not aligned between the two inodes, for example.

To address this problem more generically and dynamically, add a
transaction accounting mode that returns freed blocks to the
transaction reservation instead of the superblock counters on
transaction roll and use it when the rmapbt based algorithm is
active. This allows the chain of remap transactions to preserve the
block reservation based own its own frees and prevent premature
exhaustion regardless of the remap pattern. Note that this is only
safe for superblocks with lazy sb accounting, but the latter is
required for v5 supers and the rmap feature depends on v5.

Fixes: b3fed434 ("xfs: account format bouncing into rmapbt swapext tx reservation")
Root-caused-by: NDarrick J. Wong <darrick.wong@oracle.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>

./xfs/libxfs/xfs_inode_buf.c:56: unnecssary ==> unnecessary
./xfs/libxfs/xfs_inode_buf.c:59: behavour ==> behaviour
./xfs/libxfs/xfs_inode_buf.c:206: unitialized ==> uninitialized
Signed-off-by: NKeyur Patel <iamkeyur96@gmail.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

xlog_wait() on the CIL context can reference a freed context if the
waiter doesn't get scheduled before the CIL context is freed. This
can happen when a task is on the hard throttle and the CIL push
aborts due to a shutdown. This was detected by generic/019:

thread 1			thread 2

__xfs_trans_commit
 xfs_log_commit_cil
  <CIL size over hard throttle limit>
  xlog_wait
   schedule
				xlog_cil_push_work
				wake_up_all
				<shutdown aborts commit>
				xlog_cil_committed
				kmem_free

   remove_wait_queue
    spin_lock_irqsave --> UAF

Fix it by moving the wait queue to the CIL rather than keeping it in
in the CIL context that gets freed on push completion. Because the
wait queue is now independent of the CIL context and we might have
multiple contexts in flight at once, only wake the waiters on the
push throttle when the context we are pushing is over the hard
throttle size threshold.

Fixes: 0e7ab7ef ("xfs: Throttle commits on delayed background CIL push")
Reported-by: NYu Kuai <yukuai3@huawei.com>
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

Convert comments that reference mmap_sem to reference mmap_lock instead.

[akpm@linux-foundation.org: fix up linux-next leftovers]
[akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil]
[akpm@linux-foundation.org: more linux-next fixups, per Michel]
Signed-off-by: NMichel Lespinasse <walken@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NVlastimil Babka <vbabka@suse.cz>
Reviewed-by: NDaniel Jordan <daniel.m.jordan@oracle.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

xfs_ifree_cluster() calls xfs_perag_get() at the beginning, but forgets to
call xfs_perag_put() in one failed path.
Add the missed function call to fix it.

Fixes: ce92464c ("xfs: make xfs_trans_get_buf return an error code")
Signed-off-by: NChuhong Yuan <hslester96@gmail.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

No need to pull the fiemap definitions into almost every file in the
kernel build.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NRitesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Link: https://lore.kernel.org/r/20200523073016.2944131-5-hch@lst.deSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

The pgprot argument to __vmalloc is always PAGE_KERNEL now, so remove it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com> [hyperv]
Acked-by: Gao Xiang <xiang@kernel.org> [erofs]
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: NWei Liu <wei.liu@kernel.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200414131348.444715-22-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is always PAGE_KERNEL - for long term mappings with other properties
vmap should be used.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200414131348.444715-19-hch@lst.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the new readahead operation in iomap.  Convert XFS and ZoneFS to use
it.
Signed-off-by: NMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NWilliam Kucharski <william.kucharski@oracle.com>
Cc: Chao Yu <yuchao0@huawei.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Gao Xiang <gaoxiang25@huawei.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Link: http://lkml.kernel.org/r/20200414150233.24495-26-willy@infradead.orgSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Because of the separation of FS_XFLAG_DAX from S_DAX and the delayed
setting of S_DAX, data invalidation no longer needs to happen when
FS_XFLAG_DAX is changed.

Change xfs_ioctl_setattr_dax_invalidate() to be
xfs_ioctl_dax_check_set_cache() and alter the code to reflect the new
functionality.

Furthermore, we no longer need the locking so we remove the join_flags
logic.
Signed-off-by: NIra Weiny <ira.weiny@intel.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

The functionality in xfs_diflags_to_linux() and xfs_diflags_to_iflags() are
nearly identical.  The only difference is that *_to_linux() is called after
inode setup and disallows changing the DAX flag.

Combining them can be done with a flag which indicates if this is the initial
setup to allow the DAX flag to be properly set only at init time.

So remove xfs_diflags_to_linux() and call the modified xfs_diflags_to_iflags()
directly.

While we are here simplify xfs_diflags_to_iflags() to take struct xfs_inode and
use xfs_ip2xflags() to ensure future diflags are included correctly.
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NIra Weiny <ira.weiny@intel.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

xfs_inode_supports_dax() should reflect if the inode can support DAX not
that it is enabled for DAX.

Change the use of xfs_inode_supports_dax() to reflect only if the inode
and underlying storage support dax.

Add a new function xfs_inode_should_enable_dax() which reflects if the
inode should be enabled for DAX.
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NIra Weiny <ira.weiny@intel.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

As agreed upon[1].  We make the dax mount option a tri-state.  '-o dax'
continues to operate the same.  We add 'always', 'never', and 'inode'
(default).

[1] https://lore.kernel.org/lkml/20200405061945.GA94792@iweiny-DESK2.sc.intel.com/Signed-off-by: NIra Weiny <ira.weiny@intel.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

In prep for the new tri-state mount option which then introduces
XFS_MOUNT_DAX_NEVER.
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NIra Weiny <ira.weiny@intel.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

An earlier call of xfs_reinit_inode() from xfs_iget_cache_hit() already
handles initialization of i_rwsem.

Doing so again is unneeded.
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NIra Weiny <ira.weiny@intel.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

Dave Airlie reported the following lockdep complaint:

>  ======================================================
>  WARNING: possible circular locking dependency detected
>  5.7.0-0.rc5.20200515git1ae7efb3.1.fc33.x86_64 #1 Not tainted
>  ------------------------------------------------------
>  kswapd0/159 is trying to acquire lock:
>  ffff9b38d01a4470 (&xfs_nondir_ilock_class){++++}-{3:3},
>  at: xfs_ilock+0xde/0x2c0 [xfs]
>
>  but task is already holding lock:
>  ffffffffbbb8bd00 (fs_reclaim){+.+.}-{0:0}, at:
>  __fs_reclaim_acquire+0x5/0x30
>
>  which lock already depends on the new lock.
>
>
>  the existing dependency chain (in reverse order) is:
>
>  -> #1 (fs_reclaim){+.+.}-{0:0}:
>         fs_reclaim_acquire+0x34/0x40
>         __kmalloc+0x4f/0x270
>         kmem_alloc+0x93/0x1d0 [xfs]
>         kmem_alloc_large+0x4c/0x130 [xfs]
>         xfs_attr_copy_value+0x74/0xa0 [xfs]
>         xfs_attr_get+0x9d/0xc0 [xfs]
>         xfs_get_acl+0xb6/0x200 [xfs]
>         get_acl+0x81/0x160
>         posix_acl_xattr_get+0x3f/0xd0
>         vfs_getxattr+0x148/0x170
>         getxattr+0xa7/0x240
>         path_getxattr+0x52/0x80
>         do_syscall_64+0x5c/0xa0
>         entry_SYSCALL_64_after_hwframe+0x49/0xb3
>
>  -> #0 (&xfs_nondir_ilock_class){++++}-{3:3}:
>         __lock_acquire+0x1257/0x20d0
>         lock_acquire+0xb0/0x310
>         down_write_nested+0x49/0x120
>         xfs_ilock+0xde/0x2c0 [xfs]
>         xfs_reclaim_inode+0x3f/0x400 [xfs]
>         xfs_reclaim_inodes_ag+0x20b/0x410 [xfs]
>         xfs_reclaim_inodes_nr+0x31/0x40 [xfs]
>         super_cache_scan+0x190/0x1e0
>         do_shrink_slab+0x184/0x420
>         shrink_slab+0x182/0x290
>         shrink_node+0x174/0x680
>         balance_pgdat+0x2d0/0x5f0
>         kswapd+0x21f/0x510
>         kthread+0x131/0x150
>         ret_from_fork+0x3a/0x50
>
>  other info that might help us debug this:
>
>   Possible unsafe locking scenario:
>
>         CPU0                    CPU1
>         ----                    ----
>    lock(fs_reclaim);
>                                 lock(&xfs_nondir_ilock_class);
>                                 lock(fs_reclaim);
>    lock(&xfs_nondir_ilock_class);
>
>   *** DEADLOCK ***
>
>  4 locks held by kswapd0/159:
>   #0: ffffffffbbb8bd00 (fs_reclaim){+.+.}-{0:0}, at:
>  __fs_reclaim_acquire+0x5/0x30
>   #1: ffffffffbbb7cef8 (shrinker_rwsem){++++}-{3:3}, at:
>  shrink_slab+0x115/0x290
>   #2: ffff9b39f07a50e8
>  (&type->s_umount_key#56){++++}-{3:3}, at: super_cache_scan+0x38/0x1e0
>   #3: ffff9b39f077f258
>  (&pag->pag_ici_reclaim_lock){+.+.}-{3:3}, at:
>  xfs_reclaim_inodes_ag+0x82/0x410 [xfs]

This is a known false positive because inodes cannot simultaneously be
getting reclaimed and the target of a getxattr operation, but lockdep
doesn't know that.  We can (selectively) shut up lockdep until either
it gets smarter or we change inode reclaim not to require the ILOCK by
applying a stupid GFP_NOLOCKDEP bandaid.
Reported-by: NDave Airlie <airlied@gmail.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Tested-by: NDave Airlie <airlied@gmail.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

When writing to a delalloc region in the data fork, commit the new
allocations (of the da reservation) as unwritten so that the mappings
are only marked written once writeback completes successfully.  This
fixes the problem of stale data exposure if the system goes down during
targeted writeback of a specific region of a file, as tested by
generic/042.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

Refactor xfs_iomap_prealloc_size to be the function that dynamically
computes the per-file preallocation size by moving the allocsize= case
to the caller.  Break up the huge comment preceding the function to
annotate the relevant parts of the code, and remove the impossible
check_writeio case.
Suggested-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

When we're estimating a new speculative preallocation length for an
extending write, we should walk backwards through the extent list to
determine the number of number of blocks that are physically and
logically contiguous with the write offset, and use that as an input to
the preallocation size computation.

This way, preallocation length is truly measured by the effectiveness of
the allocator in giving us contiguous allocations without being
influenced by the state of a given extent.  This fixes both the problem
where ZERO_RANGE within an EOF can reduce preallocation, and prevents
the unnecessary shrinkage of preallocation when delalloc extents are
turned into unwritten extents.

This was found as a regression in xfs/014 after changing delalloc writes
to create unwritten extents during writeback.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

During writeback, it's possible for the quota block reservation in
xfs_iomap_write_unwritten to fail with EDQUOT because we hit the quota
limit.  This causes writeback errors for data that was already written
to disk, when it's not even guaranteed that the bmbt will expand to
exceed the quota limit.  Irritatingly, this condition is reported to
userspace as EIO by fsync, which is confusing.

We wrote the data, so allow the reservation.  That might put us slightly
above the hard limit, but it's better than losing data after a write.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

The perag structure already has a pointer to the xfs_mount, so we don't
need to pass that separately and can drop it.  Having done that, move
iter_flags so that the argument order is the same between xfs_inode_walk
and xfs_inode_walk_ag.  The latter will make things less confusing for a
future patch that enables background scanning work to be done in
parallel.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

We're not very consistent about function names for the incore inode
iteration function.  Turn them all into xfs_inode_walk* variants.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

Move the xfs_inode_ag_iterator function to be nearer xfs_inode_ag_walk
so that we don't have to scroll back and forth to figure out how the
incore inode walking function works.  No functional changes.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

This is a boolean variable, so use the bool type.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

There are a number of predicate functions that help the incore inode
walking code decide if we really want to apply the iteration function to
the inode.  These are boolean decisions, so change the return types to
boolean to match.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

Refactor the two eofb-matching logics into a single helper so that we
don't repeat ourselves.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

This is now a pointless wrapper, so kill it.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBrian Foster <bfoster@redhat.com>

The incore inode walk code passes a flags argument and a pointer from
the xfs_inode_ag_iterator caller all the way to the iteration function.
We can reduce the function complexity by passing flags through the
private pointer.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBrian Foster <bfoster@redhat.com>