Reverse mapping has had a while to soak, so remove the experimental tag.
Now that we've landed space metadata cross-referencing in scrub, the
feature actually has a purpose.

Reject rmap filesystems with an rt device until the code to support it
is actually implemented.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>

We don't support realtime filesystems with reflink either, so fail
those mounts.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>

Now that reflink is no longer experimental, reject attempts to mount
with DAX until that whole mess gets sorted out.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

Advertise this config option along with the others.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Don't use u32, use uint32_t, because this won't work in xfsprogs.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>

But reject reflink + DAX file systems for now until the code to
support reflinks on DAX is actually implemented.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
[darrick: port to 4.16]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

xfs_bmap_btalloc is given a range of file offset blocks that must be
allocated to some data/attr/cow fork.  If the fork has an extent size
hint associated with it, the request will be enlarged on both ends to
try to satisfy the alignment hint.  If free space is fragmentated,
sometimes we can allocate some blocks but not enough to fulfill any of
the requested range.  Since bmapi_allocate always trims the new extent
mapping to match the originally requested range, this results in
bmapi_write returning zero and no mapping.

The consequences of this vary -- buffered writes will simply re-call
bmapi_write until it can satisfy at least one block from the original
request.  Direct IO overwrites notice nmaps == 0 and return -ENOSPC
through the dio mechanism out to userspace with the weird result that
writes fail even when we have enough space because the ENOSPC return
overrides any partial write status.  For direct CoW writes the situation
was disastrous because nobody notices us returning an invalid zero-length
wrong-offset mapping to iomap and the write goes off into space.

Therefore, if free space is so fragmented that we managed to allocate
some space but not enough to map into even a single block of the
original allocation request range, we should break the alignment hint in
order to guarantee at least some forward progress for the direct write.
If we return a short allocation to iomap_apply it'll call back about the
remaining blocks.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

There's a really bad bug in xfs_reflink_allocate_cow -- if bmapi_write
can return a zero error code but no mappings.  This happens if there's
an extent size hint (which causes allocation requests to be rounded to
extsz granularity internally), but there wasn't a big enough chunk of
free space to start filling at the extsz granularity and fill even one
block of the range that we actually requested.

In any case, if we got no mappings we can't possibly do anything useful
with the contents of imap, so we must bail out with ENOSPC here.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Don't let the iomap callback get away with feeding us a garbage zero
length mapping -- there was a bug in xfs that resulted in those leaking
out to hilarious effect.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Since the CoW fork only exists in memory, it is incorrect to update the
on-disk quota block counts when we modify the CoW fork.  Unlike the data
fork, even real extents in the CoW fork are only delalloc-style
reservations (on-disk they're owned by the refcountbt) so they must not
be tracked in the on disk quota info.  Ensure the i_delayed_blks
accounting reflects this too.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Reflink and dedupe operations remap blocks from a source file into a
destination file.  The destination file needs exclusive locks on all
levels because we're updating its block map, but the source file isn't
undergoing any block map changes so we can use a shared lock.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

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: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Before we share blocks between files, we need to break the pnfs leases
on the layout before we start slicing and dicing the block map.  The
structure of this function sets us up for the lock contention reduction
in the next patch.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Even if we can't use the inobt/finobt cursors to count the number of
inode btree blocks, we are never allowed to clobber the cursor of the
btree being checked, so don't do this.  Found by fuzzing level = ones
in xfs/364.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Every so often we blow the ASSERT(type != XFS_IO_COW) in xfs_map_blocks
when running fsstress, as we do in generic/269.  The cause of this is
writeback racing with truncate -- writeback doesn't take the iolock, so
truncate can sneak in to decrease i_size and truncate page cache while
writeback is gathering buffer heads to schedule writeout.

If we hit this race on a block that has a CoW mapping, we'll get a valid
imap from the CoW fork but the reduced i_size trims the mapping to zero
length (which makes it invalid), so we call xfs_map_blocks to try again.
This doesn't do much anyway, since any mapping we get out of that will
also be invalid, so we might as well skip the assert and just stop.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Commit 66f36464 ("xfs: remove if_rdev") moved storing of rdev
value for special inodes to VFS inodes, but forgot to preserve the
value of i_rdev when recycling a reclaimable xfs_inode.

This was detected by xfstest overlay/017 with inodex=on mount option
and xfs base fs. The test does a lookup of overlay chardev and blockdev
right after drop caches.

Overlayfs inodes hold a reference on underlying xfs inodes when mount
option index=on is configured. If drop caches reclaim xfs inodes, before
it relclaims overlayfs inodes, that can sometimes leave a reclaimable xfs
inode and that test hits that case quite often.

When that happens, the xfs inode cache remains broken (zere i_rdev)
until the next cycle mount or drop caches.

Fixes: 66f36464 ("xfs: remove if_rdev")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Move all the inode and quota accounting updates out of xfs_bmap_btalloc
in preparation for fixing some quota accounting problems with copy on
write.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>

Refactor inode verifier error reporting into a non-libxfs function so
that we aren't encoding the message format in libxfs.  This also
changes the kernel dmesg output to resemble buffer verifier errors
more closely.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Fix all the inode number formats to be consistently (0x%llx) in all
trace point definitions.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Always zero the di_flags2 field when we free the inode so that we never
end up with an on-disk record for an unallocated inode that also has the
reflink iflag set.  This is in keeping with the general principle that
only files can have the reflink iflag set, even though we'll zero out
di_flags2 if we ever reallocate the inode.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Ensure that we've attached all the necessary dquots before performing
reflink operations so that quota accounting is accurate.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Remove the extent size hint and realtime inode relevant code from
the xfs_bmapi_reserve_delalloc since it is not called on the inode
with extent size hint set or on a realtime inode.
Signed-off-by: Shan Hai <shan.hai@oracle.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Now that buffer's b_fspriv has been split, just replace the current
singly linked list of xfs_log_items, by the list_head infrastructure.

Also, remove the xfs_log_item argument from xfs_buf_resubmit_failed_buffers(),
there is no need for this argument, once the log items can be walked
through the list_head in the buffer.
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
[darrick: minor style cleanups]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

By splitting the b_fspriv field into two different fields (b_log_item
and b_li_list). It's possible to get rid of an old ABI workaround, by
using the new b_log_item field to store xfs_buf_log_item separated from
the log items attached to the buffer, which will be linked in the new
b_li_list field.

This way, there is no more need to reorder the log items list to place
the buf_log_item at the beginning of the list, simplifying a bit the
logic to handle buffer IO.

This also opens the possibility to change buffer's log items list into a
proper list_head.

b_log_item field is still defined as a void *, because it is still used
by the log buffers to store xlog_in_core structures, and there is no
need to add an extra field on xfs_buf just for xlog_in_core.
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
[darrick: minor style changes]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Take advantage of the rework on xfs_buf log items list, to get rid of
ths typedef for xfs_buf_log_item.

This patch also fix some indentation alignment issues found along the way.
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Fix compiler warning on non-debug build
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

Currently, we don't check sb_agblocks or sb_agblklog when we validate
the superblock, which means that we can fuzz garbage values into those
values and the mount succeeds.  This leads to all sorts of UBSAN
warnings in xfs/350 since we can then coerce other parts of xfs into
shifting by ridiculously large values.

Once we've validated agblocks, make sure the agcount makes sense.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

Eryu Guan reported seeing occasional hangs when running generic/269 with
a new fsstress that supports clonerange/deduperange.  The cause of this
hang is an infinite loop when we convert the CoW fork extents from
unwritten to real just prior to writing the pages out; the infinite
loop happens because there's nothing in the CoW fork to convert, and so
it spins forever.

The fundamental issue here is that when we go to perform these CoW fork
conversions, we're supposed to have an extent waiting for us, but the
low space CoW reaper has snuck in and blown them away!  There are four
conditions that can dissuade the reaper from touching our file -- no
reflink iflag; dirty page cache; writeback in progress; or directio in
progress.  We check the four conditions prior to taking the locks, but
we neglect to recheck them once we have the locks, which is how we end
up whacking the writeback that's in progress.

Therefore, refactor the four checks into a helper function and call it
once again once we have the locks to make sure we really want to reap
the inode.  While we're at it, add an ASSERT for this weird condition so
that we'll fail noisily if we ever screw this up again.
Reported-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Tested-by: Eryu Guan <eguan@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

xfs_bmbt_irec.br_blockcount is declared as xfs_filblks_t, which is an
unsigned 64-bit integer.  Though the bmbt helpers will never set a value
larger than 2^21 (since the underlying on-disk extent record has a
length field that is only 21 bits wide), we should be a little defensive
about checking that a bmbt record doesn't exceed what we're expecting or
overflow into the next AG.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

A btree format inode fork with zero records makes no sense, so reject it
if we see it, or else we can miscalculate memory allocations.  Found by
zeroes fuzzing {a,u3}.bmbt.numrecs in xfs/{374,378,412} with KASAN.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

In the attribute leaf verifier, we can check for obviously bad values of
firstused and count so that later attempts at lasthash don't run off the
end of the memory buffer.  Found by ones fuzzing hdr.count in xfs/400 with
KASAN.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

In xfs_scrub_dir_rec, we must walk through the directory block entries
to arrive at the offset given by the hash structure.  If we blindly
trust the hash address, we can end up midway into a directory entry and
stray outside the block.  Found by lastbit fuzzing lents[3].address in
xfs/390 with KASAN enabled.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

Don't iunlock an unlocked inode, which can happen if the parent pointer
scrubber bails out with sc->ip unlocked while trying to grab the parent
directory inode.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

Whenever we load a buffer, explicitly re-call the structure verifier to
ensure that memory isn't corrupting things.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

Use an inode's block mappings to cross-reference inode block counters.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

While we're scrubbing various btrees, cross-reference the records
with the other metadata.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

During metadata btree scrub, we should cross-reference with the
reference counts.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

Cross reference the refcount data with the rmap data to check that the
number of rmaps for a given block match the refcount of that block, and
that CoW blocks (which are owned entirely by the refcountbt) are tracked
as well.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

When scrubbing various btrees, we should cross-reference the records
with the reverse mapping btree and ensure that traversing the btree
finds the same number of blocks that the rmapbt thinks are owned by
that btree.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

Cross-reference the inode btrees with the other metadata when we
scrub the filesystem.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>