xfs: remove m_attroffset

With the upcoming v3 inodes the default attroffset needs to be calculated
for each specific inode, so we can't cache it in the superblock anymore.

Also replace the assert for wrong inode sizes with a proper error check
also included in non-debug builds.  Note that the ENOSYS return for
that might seem odd, but that error is returned by xfs_mount_validate_sb
for all theoretically valid but not supported filesystem geometries.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef 'Jeff' Sipek <jeffpc@josefsipek.net>

1 files changed, 40 insertions, 16 deletions

diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
index 47a87de35af..3a6ed426327 100644
--- a/fs/xfs/xfs_bmap.c
+++ b/fs/xfs/xfs_bmap.c
@@ -3569,6 +3569,27 @@ xfs_bmap_extents_to_btree(
 }
 
 /*
+ * Calculate the default attribute fork offset for newly created inodes.
+ */
+uint
+xfs_default_attroffset(
+	struct xfs_inode	*ip)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	uint			offset;
+
+	if (mp->m_sb.sb_inodesize == 256) {
+		offset = XFS_LITINO(mp) -
+				XFS_BMDR_SPACE_CALC(MINABTPTRS);
+	} else {
+		offset = XFS_BMDR_SPACE_CALC(6 * MINABTPTRS);
+	}
+
+	ASSERT(offset < XFS_LITINO(mp));
+	return offset;
+}
+
+/*
  * Helper routine to reset inode di_forkoff field when switching
  * attribute fork from local to extent format - we reset it where
  * possible to make space available for inline data fork extents.
@@ -3580,15 +3601,18 @@ xfs_bmap_forkoff_reset(
 	int		whichfork)
 {
 	if (whichfork == XFS_ATTR_FORK &&
-	    (ip->i_d.di_format != XFS_DINODE_FMT_DEV) &&
-	    (ip->i_d.di_format != XFS_DINODE_FMT_UUID) &&
-	    (ip->i_d.di_format != XFS_DINODE_FMT_BTREE) &&
-	    ((mp->m_attroffset >> 3) > ip->i_d.di_forkoff)) {
-		ip->i_d.di_forkoff = mp->m_attroffset >> 3;
-		ip->i_df.if_ext_max = XFS_IFORK_DSIZE(ip) /
-					(uint)sizeof(xfs_bmbt_rec_t);
-		ip->i_afp->if_ext_max = XFS_IFORK_ASIZE(ip) /
-					(uint)sizeof(xfs_bmbt_rec_t);
+	    ip->i_d.di_format != XFS_DINODE_FMT_DEV &&
+	    ip->i_d.di_format != XFS_DINODE_FMT_UUID &&
+	    ip->i_d.di_format != XFS_DINODE_FMT_BTREE) {
+		uint	dfl_forkoff = xfs_default_attroffset(ip) >> 3;
+
+		if (dfl_forkoff > ip->i_d.di_forkoff) {
+			ip->i_d.di_forkoff = dfl_forkoff;
+			ip->i_df.if_ext_max =
+				XFS_IFORK_DSIZE(ip) / sizeof(xfs_bmbt_rec_t);
+			ip->i_afp->if_ext_max =
+				XFS_IFORK_ASIZE(ip) / sizeof(xfs_bmbt_rec_t);
+		}
 	}
 }
 
@@ -4057,7 +4081,7 @@ xfs_bmap_add_attrfork(
 	case XFS_DINODE_FMT_BTREE:
 		ip->i_d.di_forkoff = xfs_attr_shortform_bytesfit(ip, size);
 		if (!ip->i_d.di_forkoff)
-			ip->i_d.di_forkoff = mp->m_attroffset >> 3;
+			ip->i_d.di_forkoff = xfs_default_attroffset(ip) >> 3;
 		else if (mp->m_flags & XFS_MOUNT_ATTR2)
 			version = 2;
 		break;
@@ -4204,12 +4228,12 @@ xfs_bmap_compute_maxlevels(
 	 * (a signed 16-bit number, xfs_aextnum_t).
 	 *
 	 * Note that we can no longer assume that if we are in ATTR1 that
-	 * the fork offset of all the inodes will be (m_attroffset >> 3)
-	 * because we could have mounted with ATTR2 and then mounted back
-	 * with ATTR1, keeping the di_forkoff's fixed but probably at
-	 * various positions. Therefore, for both ATTR1 and ATTR2
-	 * we have to assume the worst case scenario of a minimum size
-	 * available.
+	 * the fork offset of all the inodes will be
+	 * (xfs_default_attroffset(ip) >> 3) because we could have mounted
+	 * with ATTR2 and then mounted back with ATTR1, keeping the
+	 * di_forkoff's fixed but probably at various positions. Therefore,
+	 * for both ATTR1 and ATTR2 we have to assume the worst case scenario
+	 * of a minimum size available.
 	 */
 	if (whichfork == XFS_DATA_FORK) {
 		maxleafents = MAXEXTNUM;