Merge tag 'xfs-5.10-fixes-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs fixes from Darrick Wong:
 "The critical fixes are for a crash that someone reported in the xattr
  code on 32-bit arm last week; and a revert of the rmap key comparison
  change from last week as it was totally wrong. I need a vacation. :(

  Summary:

   - Fix various deficiencies in online fsck's metadata checking code

   - Fix an integer casting bug in the xattr code on 32-bit systems

   - Fix a hang in an inode walk when the inode index is corrupt

   - Fix error codes being dropped when initializing per-AG structures

   - Fix nowait directio writes that partially succeed but return EAGAIN

   - Revert last week's rmap comparison patch because it was wrong"

* tag 'xfs-5.10-fixes-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: revert "xfs: fix rmap key and record comparison functions"
  xfs: don't allow NOWAIT DIO across extent boundaries
  xfs: return corresponding errcode if xfs_initialize_perag() fail
  xfs: ensure inobt record walks always make forward progress
  xfs: fix forkoff miscalculation related to XFS_LITINO(mp)
  xfs: directory scrub should check the null bestfree entries too
  xfs: strengthen rmap record flags checking
  xfs: fix the minrecs logic when dealing with inode root child blocks

1 files changed, 27 insertions, 18 deletions

diff --git a/fs/xfs/scrub/btree.c b/fs/xfs/scrub/btree.c
index f52a7b8256f9..debf392e0515 100644
--- a/fs/xfs/scrub/btree.c
+++ b/fs/xfs/scrub/btree.c
@@ -452,32 +452,41 @@ xchk_btree_check_minrecs(
 	int			level,
 	struct xfs_btree_block	*block)
 {
-	unsigned int		numrecs;
-	int			ok_level;
-
-	numrecs = be16_to_cpu(block->bb_numrecs);
+	struct xfs_btree_cur	*cur = bs->cur;
+	unsigned int		root_level = cur->bc_nlevels - 1;
+	unsigned int		numrecs = be16_to_cpu(block->bb_numrecs);
 
 	/* More records than minrecs means the block is ok. */
-	if (numrecs >= bs->cur->bc_ops->get_minrecs(bs->cur, level))
+	if (numrecs >= cur->bc_ops->get_minrecs(cur, level))
 		return;
 
 	/*
-	 * Certain btree blocks /can/ have fewer than minrecs records.  Any
-	 * level greater than or equal to the level of the highest dedicated
-	 * btree block are allowed to violate this constraint.
-	 *
-	 * For a btree rooted in a block, the btree root can have fewer than
-	 * minrecs records.  If the btree is rooted in an inode and does not
-	 * store records in the root, the direct children of the root and the
-	 * root itself can have fewer than minrecs records.
+	 * For btrees rooted in the inode, it's possible that the root block
+	 * contents spilled into a regular ondisk block because there wasn't
+	 * enough space in the inode root.  The number of records in that
+	 * child block might be less than the standard minrecs, but that's ok
+	 * provided that there's only one direct child of the root.
 	 */
-	ok_level = bs->cur->bc_nlevels - 1;
-	if (bs->cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
-		ok_level--;
-	if (level >= ok_level)
+	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
+	    level == cur->bc_nlevels - 2) {
+		struct xfs_btree_block	*root_block;
+		struct xfs_buf		*root_bp;
+		int			root_maxrecs;
+
+		root_block = xfs_btree_get_block(cur, root_level, &root_bp);
+		root_maxrecs = cur->bc_ops->get_dmaxrecs(cur, root_level);
+		if (be16_to_cpu(root_block->bb_numrecs) != 1 ||
+		    numrecs <= root_maxrecs)
+			xchk_btree_set_corrupt(bs->sc, cur, level);
 		return;
+	}
 
-	xchk_btree_set_corrupt(bs->sc, bs->cur, level);
+	/*
+	 * Otherwise, only the root level is allowed to have fewer than minrecs
+	 * records or keyptrs.
+	 */
+	if (level < root_level)
+		xchk_btree_set_corrupt(bs->sc, cur, level);
 }
 
 /*