Pull vfs cleanups from Al Viro:
 "More cleanups from Christoph"

* 'work.preadv2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  nfsd: use RWF_SYNC
  fs: add RWF_DSYNC aand RWF_SYNC
  ceph: use generic_write_sync
  fs: simplify the generic_write_sync prototype
  fs: add IOCB_SYNC and IOCB_DSYNC
  direct-io: remove the offset argument to dio_complete
  direct-io: eliminate the offset argument to ->direct_IO
  xfs: eliminate the pos variable in xfs_file_dio_aio_write
  filemap: remove the pos argument to generic_file_direct_write
  filemap: remove pos variables in generic_file_read_iter

Pull UDF fixes from Jan Kara:
 "A fix for UDF crash on corrupted media and one UDF header fixup"

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  udf: Export superblock magic to userspace
  udf: Prevent stack overflow on corrupted filesystem mount

Backmerge to resolve a conflict in ovl_lookup_real();
"ovl_lookup_real(): use lookup_one_len_unlocked()" instead,
but it was too late in the cycle to rebase.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

The rest of work.xattr stuff isn't needed for this branch

The kiocb already has the new position, so use that.  The only interesting
case is AIO, where we currently don't bother updating ki_pos.  We're about
to free the kiocb after we're done, so we might as well update it to make
everyone's life simpler.

While we're at it also return the bytes written argument passed in if
we were successful so that the boilerplate error switch code in the
callers can go away.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

This will allow us to do per-I/O sync file writes, as required by a lot
of fileservers or storage targets.

XXX: Will need a few additional audits for O_DSYNC

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Including blkdev_direct_IO and dax_do_io.  It has to be ki_pos to actually
work, so eliminate the superflous argument.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Currently UDF superblock magic doesn't appear in any userspace header
files and thus userspace apps have hard time checking for this fs. Let's
export the magic to userspace as with any other filesystem.

Signed-off-by: Jan Kara <jack@suse.cz>

Presently, a corrupted or malicious UDF filesystem containing a very large
number (or cycle) of Logical Volume Integrity Descriptor extent
indirections may trigger a stack overflow and kernel panic in
udf_load_logicalvolint() on mount.

Replace the unnecessary recursion in udf_load_logicalvolint() with
simple iteration. Set an arbitrary limit of 1000 indirections (which would
have almost certainly overflowed the stack without this fix), and treat
such cases as if there were no LVID.

Signed-off-by: Alden Tondettar <alden.tondettar@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>