Merge tag 'xfs-fixes-for-linus-4.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs

Pull xfs fixes from Dave Chinner:
 "This update contains fixes for most of the outstanding regressions
  introduced with the 4.9-rc1 XFS merge. There is also a fix for an
  iomap bug, too.

  This is a quite a bit larger than I'd prefer for a -rc3, but most of
  the change comes from cleaning up the new reflink copy on write code;
  it's much simpler and easier to understand now. These changes fixed
  several bugs in the new code, and it wasn't clear that there was an
  easier/simpler way to fix them. The rest of the fixes are the usual
  size you'd expect at this stage.

  I've left the commits to soak in linux-next for a some extra time
  because of the size before asking you to pull, no new problems with
  them have been reported so I think it's all OK.

  Summary:
   - iomap page offset masking fix for page faults
   - add IOMAP_REPORT to distinguish between read and fiemap map
     requests
   - cleanups to new shared data extent code
   - fix mount active status on failed log recovery
   - fix broken dquots in a buffer calculation
   - fix locking order issues and merge xfs_reflink_remap_range and
     xfs_file_share_range
   - rework unmapping of CoW extents and remove now unused functions
   - clean state when CoW is done"

* tag 'xfs-fixes-for-linus-4.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (25 commits)
  xfs: clear cowblocks tag when cow fork is emptied
  xfs: fix up inode cowblocks tracking tracepoints
  fs: Do to trim high file position bits in iomap_page_mkwrite_actor
  xfs: remove xfs_bunmapi_cow
  xfs: optimize xfs_reflink_end_cow
  xfs: optimize xfs_reflink_cancel_cow_blocks
  xfs: refactor xfs_bunmapi_cow
  xfs: optimize writes to reflink files
  xfs: don't bother looking at the refcount tree for reads
  xfs: handle "raw" delayed extents xfs_reflink_trim_around_shared
  xfs: add xfs_trim_extent
  iomap: add IOMAP_REPORT
  xfs: merge xfs_reflink_remap_range and xfs_file_share_range
  xfs: remove xfs_file_wait_for_io
  xfs: move inode locking from xfs_reflink_remap_range to xfs_file_share_range
  xfs: fix the same_inode check in xfs_file_share_range
  xfs: remove the same fs check from xfs_file_share_range
  libxfs: v3 inodes are only valid on crc-enabled filesystems
  libxfs: clean up _calc_dquots_per_chunk
  xfs: unset MS_ACTIVE if mount fails
  ...

1 files changed, 41 insertions, 16 deletions

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index d907eb9f8ef3..436e109bb01e 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -566,6 +566,17 @@ xfs_file_iomap_begin_delay(
 	xfs_bmap_search_extents(ip, offset_fsb, XFS_DATA_FORK, &eof, &idx,
 			&got, &prev);
 	if (!eof && got.br_startoff <= offset_fsb) {
+		if (xfs_is_reflink_inode(ip)) {
+			bool		shared;
+
+			end_fsb = min(XFS_B_TO_FSB(mp, offset + count),
+					maxbytes_fsb);
+			xfs_trim_extent(&got, offset_fsb, end_fsb - offset_fsb);
+			error = xfs_reflink_reserve_cow(ip, &got, &shared);
+			if (error)
+				goto out_unlock;
+		}
+
 		trace_xfs_iomap_found(ip, offset, count, 0, &got);
 		goto done;
 	}
@@ -961,19 +972,13 @@ xfs_file_iomap_begin(
 	struct xfs_mount	*mp = ip->i_mount;
 	struct xfs_bmbt_irec	imap;
 	xfs_fileoff_t		offset_fsb, end_fsb;
-	bool			shared, trimmed;
 	int			nimaps = 1, error = 0;
+	bool			shared = false, trimmed = false;
 	unsigned		lockmode;
 
 	if (XFS_FORCED_SHUTDOWN(mp))
 		return -EIO;
 
-	if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && xfs_is_reflink_inode(ip)) {
-		error = xfs_reflink_reserve_cow_range(ip, offset, length);
-		if (error < 0)
-			return error;
-	}
-
 	if ((flags & IOMAP_WRITE) && !IS_DAX(inode) &&
 		   !xfs_get_extsz_hint(ip)) {
 		/* Reserve delalloc blocks for regular writeback. */
@@ -981,7 +986,16 @@ xfs_file_iomap_begin(
 				iomap);
 	}
 
-	lockmode = xfs_ilock_data_map_shared(ip);
+	/*
+	 * COW writes will allocate delalloc space, so we need to make sure
+	 * to take the lock exclusively here.
+	 */
+	if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && xfs_is_reflink_inode(ip)) {
+		lockmode = XFS_ILOCK_EXCL;
+		xfs_ilock(ip, XFS_ILOCK_EXCL);
+	} else {
+		lockmode = xfs_ilock_data_map_shared(ip);
+	}
 
 	ASSERT(offset <= mp->m_super->s_maxbytes);
 	if ((xfs_fsize_t)offset + length > mp->m_super->s_maxbytes)
@@ -991,16 +1005,24 @@ xfs_file_iomap_begin(
 
 	error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
 			       &nimaps, 0);
-	if (error) {
-		xfs_iunlock(ip, lockmode);
-		return error;
+	if (error)
+		goto out_unlock;
+
+	if (flags & IOMAP_REPORT) {
+		/* Trim the mapping to the nearest shared extent boundary. */
+		error = xfs_reflink_trim_around_shared(ip, &imap, &shared,
+				&trimmed);
+		if (error)
+			goto out_unlock;
 	}
 
-	/* Trim the mapping to the nearest shared extent boundary. */
-	error = xfs_reflink_trim_around_shared(ip, &imap, &shared, &trimmed);
-	if (error) {
-		xfs_iunlock(ip, lockmode);
-		return error;
+	if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && xfs_is_reflink_inode(ip)) {
+		error = xfs_reflink_reserve_cow(ip, &imap, &shared);
+		if (error)
+			goto out_unlock;
+
+		end_fsb = imap.br_startoff + imap.br_blockcount;
+		length = XFS_FSB_TO_B(mp, end_fsb) - offset;
 	}
 
 	if ((flags & IOMAP_WRITE) && imap_needs_alloc(inode, &imap, nimaps)) {
@@ -1039,6 +1061,9 @@ xfs_file_iomap_begin(
 	if (shared)
 		iomap->flags |= IOMAP_F_SHARED;
 	return 0;
+out_unlock:
+	xfs_iunlock(ip, lockmode);
+	return error;
 }
 
 static int