Merge tag 'xfs-4.20-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pul xfs updates from Dave Chinner:
 "There's not a huge amount of change in this cycle - Darrick has been
  out of action for a couple of months (hence me sending the last few
  pull requests), so we decided a quiet cycle mainly focussed on bug
  fixes was a good idea. Darrick will take the helm again at the end of
  this merge window.

  FYI, I may be sending another update later in the cycle - there's a
  pending rework of the clone/dedupe_file_range code that fixes numerous
  bugs that is spread amongst the VFS, XFS and ocfs2 code. It has been
  reviewed and tested, Al and I just need to work out the details of the
  merge, so it may come from him rather than me.

  Summary:

   - only support filesystems with unwritten extents

   - add definition for statfs XFS magic number

   - remove unused parameters around reflink code

   - more debug for dangling delalloc extents

   - cancel COW extents on extent swap targets

   - fix quota stats output and clean up the code

   - refactor some of the attribute code in preparation for parent
     pointers

   - fix several buffer handling bugs"

* tag 'xfs-4.20-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (21 commits)
  xfs: cancel COW blocks before swapext
  xfs: clear ail delwri queued bufs on unmount of shutdown fs
  xfs: use offsetof() in place of offset macros for __xfsstats
  xfs: Fix xqmstats offsets in /proc/fs/xfs/xqmstat
  xfs: fix use-after-free race in xfs_buf_rele
  xfs: Add attibute remove and helper functions
  xfs: Add attibute set and helper functions
  xfs: Add helper function xfs_attr_try_sf_addname
  xfs: Move fs/xfs/xfs_attr.h to fs/xfs/libxfs/xfs_attr.h
  xfs: issue log message on user force shutdown
  xfs: fix buffer state management in xrep_findroot_block
  xfs: always assign buffer verifiers when one is provided
  xfs: xrep_findroot_block should reject root blocks with siblings
  xfs: add a define for statfs magic to uapi
  xfs: print dangling delalloc extents
  xfs: fix fork selection in xfs_find_trim_cow_extent
  xfs: remove the unused trimmed argument from xfs_reflink_trim_around_shared
  xfs: remove the unused shared argument to xfs_reflink_reserve_cow
  xfs: handle zeroing in xfs_file_iomap_begin_delay
  xfs: remove suport for filesystems without unwritten extent flag
  ...

include/uapi/linux/magic.h

@@ -29,6 +29,7 @@
 #define HPFS_SUPER_MAGIC	0xf995e849
 #define ISOFS_SUPER_MAGIC	0x9660
 #define JFFS2_SUPER_MAGIC	0x72b6
+#define XFS_SUPER_MAGIC		0x58465342	/* "XFSB" */
 #define PSTOREFS_MAGIC		0x6165676C
 #define EFIVARFS_MAGIC		0xde5e81e4
 #define HOSTFS_SUPER_MAGIC	0x00c0ffee