If a callback break occurs (change notification), afs_getattr() needs to
issue an FS.FetchStatus RPC operation to update the status of the file
being examined by the stat-family of system calls.

Fix afs_getattr() to do this if AFS_VNODE_CB_PROMISED has been cleared
on a vnode by a callback break.  Skip this if AT_STATX_DONT_SYNC is set.

This can be tested by appending to a file on one AFS client and then
using "stat -L" to examine its length on a machine running kafs.  This
can also be watched through tracing on the kafs machine.  The callback
break is seen:

     kworker/1:1-46      [001] .....   978.910812: afs_cb_call: c=0000005f YFSCB.CallBack
     kworker/1:1-46      [001] ...1.   978.910829: afs_cb_break: 100058:23b4c:242d2c2 b=2 s=1 break-cb
     kworker/1:1-46      [001] .....   978.911062: afs_call_done:    c=0000005f ret=0 ab=0 [0000000082994ead]

And then the stat command generated no traffic if unpatched, but with
this change a call to fetch the status can be observed:

            stat-4471    [000] .....   986.744122: afs_make_fs_call: c=000000ab 100058:023b4c:242d2c2 YFS.FetchStatus
            stat-4471    [000] .....   986.745578: afs_call_done:    c=000000ab ret=0 ab=0 [0000000087fc8c84]

Fixes: 08e0e7c82eea ("[AF_RXRPC]: Make the in-kernel AFS filesystem use AF_RXRPC.")
Reported-by: Markus Suvanto <markus.suvanto@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Tested-by: Markus Suvanto <markus.suvanto@gmail.com>
Tested-by: kafs-testing+fedora34_64checkkafs-build-496@auristor.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216010
Link: https://lore.kernel.org/r/165308359800.162686.14122417881564420962.stgit@warthog.procyon.org.uk/ # v1
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull io_uring fixes from Jens Axboe:
 "Two small changes fixing issues from the 5.18 merge window:

   - Fix wrong ordering of a tracepoint (Dylan)

   - Fix MSG_RING on IOPOLL rings (me)"

* tag 'io_uring-5.18-2022-05-18' of git://git.kernel.dk/linux-block:
  io_uring: don't attempt to IOPOLL for MSG_RING requests
  io_uring: fix ordering of args in io_uring_queue_async_work

We gate whether to IOPOLL for a request on whether the opcode is allowed
on a ring setup for IOPOLL and if it's got a file assigned. MSG_RING
is the only one that allows a file yet isn't pollable, it's merely
supported to allow communication on an IOPOLL ring, not because we can
poll for completion of it.

Put the assigned file early and clear it, so we don't attempt to poll
for it.

Reported-by: syzbot+1a0a53300ce782f8b3ad@syzkaller.appspotmail.com
Fixes: 3f1d52abf098 ("io_uring: defer msg-ring file validity check until command issue")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull gfs2 fixes from Andreas Gruenbacher:
 "We've finally identified commit dc732906c245 ("gfs2: Introduce flag
  for glock holder auto-demotion") to be the other cause of the
  filesystem corruption we've been seeing. This feature isn't strictly
  necessary anymore, so we've decided to stop using it for now.

  With this and the gfs_iomap_end rounding fix you've already seen
  ("gfs2: Fix filesystem block deallocation for short writes" in this
  pull request), we're corruption free again now.

   - Fix filesystem block deallocation for short writes.

   - Stop using glock holder auto-demotion for now.

   - Get rid of buffered writes inefficiencies due to page faults being
     disabled.

   - Minor other cleanups"

* tag 'gfs2-v5.18-rc4-fix3' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  gfs2: Stop using glock holder auto-demotion for now
  gfs2: buffered write prefaulting
  gfs2: Align read and write chunks to the page cache
  gfs2: Pull return value test out of should_fault_in_pages
  gfs2: Clean up use of fault_in_iov_iter_{read,write}able
  gfs2: Variable rename
  gfs2: Fix filesystem block deallocation for short writes

We're having unresolved issues with the glock holder auto-demotion mechanism
introduced in commit dc732906c245.  This mechanism was assumed to be essential
for avoiding frequent short reads and writes until commit 296abc0d91d8
("gfs2: No short reads or writes upon glock contention").  Since then,
when the inode glock is lost, it is simply re-acquired and the operation
is resumed.  This means that apart from the performance penalty, we
might as well drop the inode glock before faulting in pages, and
re-acquire it afterwards.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

In gfs2_file_buffered_write, to increase the likelihood that all the
user memory we're trying to write will be resident in memory, carry out
the write in chunks and fault in each chunk of user memory before trying
to write it.  Otherwise, some workloads will trigger frequent short
"internal" writes, causing filesystem blocks to be allocated and then
partially deallocated again when writing into holes, which is wasteful
and breaks reservations.

Neither the chunked writes nor any of the short "internal" writes are
user visible.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Align the chunks that reads and writes are carried out in to the page
cache rather than the user buffers.  This will be more efficient in
general, especially for allocating writes.  Optimizing the case that the
user buffer is gfs2 backed isn't very useful; we only need to make sure
we won't deadlock.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Pull the return value test of the previous read or write operation out
of should_fault_in_pages().  In a following patch, we'll fault in pages
before the I/O and there will be no return value to check.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

No need to store the return value of the fault_in functions in separate
variables.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Instead of counting the number of bytes read from the filesystem,
functions gfs2_file_direct_read and gfs2_file_read_iter count the number
of bytes written into the user buffer.  Conversely, functions
gfs2_file_direct_write and gfs2_file_buffered_write count the number of
bytes read from the user buffer.  This is nothing but confusing, so
change the read functions to count how many bytes they have read, and
the write functions to count how many bytes they have written.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>