Changes since last update:

- Add some locking assertions for the _ilock helpers.
 - Revert the XFS_QMOPT_NOLOCK patch; after discussion with hch the
   online fsck patch that would have needed it has been redesigned and
   no longer needs it.
 - Fix behavioral regression of SEEK_HOLE/DATA with negative offsets to match
   4.12-era XFS behavior.
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Merge tag 'xfs-4.13-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull XFS fixes from Darrick Wong:
 "Largely debugging and regression fixes.

   - Add some locking assertions for the _ilock helpers.

   - Revert the XFS_QMOPT_NOLOCK patch; after discussion with hch the
     online fsck patch that would have needed it has been redesigned and
     no longer needs it.

   - Fix behavioral regression of SEEK_HOLE/DATA with negative offsets
     to match 4.12-era XFS behavior"

* tag 'xfs-4.13-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  vfs: in iomap seek_{hole,data}, return -ENXIO for negative offsets
  Revert "xfs: grab dquots without taking the ilock"
  xfs: assert locking precondition in xfs_readlink_bmap_ilocked
  xfs: assert locking precondіtion in xfs_attr_list_int_ilocked
  xfs: fixup xfs_attr_get_ilocked

fs/iomap.c

@@ -610,8 +610,8 @@ iomap_seek_hole(struct inode *inode, loff_t offset, const struct iomap_ops *ops)
 	loff_t length = size - offset;
 	loff_t ret;
 
-	/* Nothing to be found beyond the end of the file. */
-	if (offset >= size)
+	/* Nothing to be found before or beyond the end of the file. */
+	if (offset < 0 || offset >= size)
 		return -ENXIO;
 
 	while (length > 0) {
@@ -656,8 +656,8 @@ iomap_seek_data(struct inode *inode, loff_t offset, const struct iomap_ops *ops)
 	loff_t length = size - offset;
 	loff_t ret;
 
-	/* Nothing to be found beyond the end of the file. */
-	if (offset >= size)
+	/* Nothing to be found before or beyond the end of the file. */
+	if (offset < 0 || offset >= size)
 		return -ENXIO;
 
 	while (length > 0) {

fs/xfs/libxfs/xfs_attr.c

@@ -114,12 +114,14 @@ xfs_inode_hasattr(
  * Overall external interface routines.
  *========================================================================*/
 
-/* Retrieve an extended attribute and its value.  Must have iolock. */
+/* Retrieve an extended attribute and its value.  Must have ilock. */
 int
 xfs_attr_get_ilocked(
 	struct xfs_inode	*ip,
 	struct xfs_da_args	*args)
 {
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
+
 	if (!xfs_inode_hasattr(ip))
 		return -ENOATTR;
 	else if (ip->i_d.di_aformat == XFS_DINODE_FMT_LOCAL)

fs/xfs/libxfs/xfs_quota_defs.h

@@ -136,8 +136,6 @@ typedef uint16_t	xfs_qwarncnt_t;
  */
 #define XFS_QMOPT_INHERIT	0x1000000
 
-#define XFS_QMOPT_NOLOCK	0x2000000 /* don't ilock during dqget */
-
 /*
  * flags to xfs_trans_mod_dquot.
  */

fs/xfs/xfs_attr_list.c

@@ -463,6 +463,8 @@ xfs_attr_list_int_ilocked(
 {
 	struct xfs_inode		*dp = context->dp;
 
+	ASSERT(xfs_isilocked(dp, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
+
 	/*
 	 * Decide on what work routines to call based on the inode size.
 	 */

fs/xfs/xfs_dquot.c

@@ -472,23 +472,18 @@ xfs_qm_dqtobp(
 	struct xfs_mount	*mp = dqp->q_mount;
 	xfs_dqid_t		id = be32_to_cpu(dqp->q_core.d_id);
 	struct xfs_trans	*tp = (tpp ? *tpp : NULL);
-	uint			lock_mode = 0;
+	uint			lock_mode;
 
 	quotip = xfs_quota_inode(dqp->q_mount, dqp->dq_flags);
 	dqp->q_fileoffset = (xfs_fileoff_t)id / mp->m_quotainfo->qi_dqperchunk;
 
-	ASSERT(!(flags & XFS_QMOPT_NOLOCK) ||
-		xfs_isilocked(quotip, XFS_ILOCK_SHARED) ||
-		xfs_isilocked(quotip, XFS_ILOCK_EXCL));
-	if (!(flags & XFS_QMOPT_NOLOCK))
-		lock_mode = xfs_ilock_data_map_shared(quotip);
+	lock_mode = xfs_ilock_data_map_shared(quotip);
 	if (!xfs_this_quota_on(dqp->q_mount, dqp->dq_flags)) {
 		/*
 		 * Return if this type of quotas is turned off while we
 		 * didn't have the quota inode lock.
 		 */
-		if (lock_mode)
-			xfs_iunlock(quotip, lock_mode);
+		xfs_iunlock(quotip, lock_mode);
 		return -ESRCH;
 	}
 
@@ -498,8 +493,7 @@ xfs_qm_dqtobp(
 	error = xfs_bmapi_read(quotip, dqp->q_fileoffset,
 			       XFS_DQUOT_CLUSTER_SIZE_FSB, &map, &nmaps, 0);
 
-	if (lock_mode)
-		xfs_iunlock(quotip, lock_mode);
+	xfs_iunlock(quotip, lock_mode);
 	if (error)
 		return error;
 

fs/xfs/xfs_symlink.c

@@ -61,6 +61,8 @@ xfs_readlink_bmap_ilocked(
 	int			fsblocks = 0;
 	int			offset;
 
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
+
 	fsblocks = xfs_symlink_blocks(mp, pathlen);
 	error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0);
 	if (error)