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>

fs/xfs/xfs_attr_leaf.c

@@ -155,7 +155,8 @@ xfs_attr_shortform_bytesfit(xfs_inode_t *dp, int bytes)
 		 * minimum offset only needs to be the space required for 
 		 * the btree root.
 		 */ 
-		if (!dp->i_d.di_forkoff && dp->i_df.if_bytes > mp->m_attroffset)
+		if (!dp->i_d.di_forkoff && dp->i_df.if_bytes >
+		    xfs_default_attroffset(dp))
 			dsize = XFS_BMDR_SPACE_CALC(MINDBTPTRS);
 		break;
 

fs/xfs/xfs_bmap.c

@@ -3568,6 +3568,27 @@ xfs_bmap_extents_to_btree(
 	return 0;
 }
 
+/*
+ * 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
@@ -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;

fs/xfs/xfs_bmap.h

@@ -338,6 +338,10 @@ xfs_check_nostate_extents(
 	xfs_extnum_t		idx,
 	xfs_extnum_t		num);
 
+uint
+xfs_default_attroffset(
+	struct xfs_inode	*ip);
+
 #ifdef __KERNEL__
 
 /*

fs/xfs/xfs_mount.c

@@ -256,6 +256,22 @@ xfs_mount_validate_sb(
 		return XFS_ERROR(ENOSYS);
 	}
 
+	/*
+	 * Currently only very few inode sizes are supported.
+	 */
+	switch (sbp->sb_inodesize) {
+	case 256:
+	case 512:
+	case 1024:
+	case 2048:
+		break;
+	default:
+		xfs_fs_mount_cmn_err(flags,
+			"inode size of %d bytes not supported",
+			sbp->sb_inodesize);
+		return XFS_ERROR(ENOSYS);
+	}
+
 	if (xfs_sb_validate_fsb_count(sbp, sbp->sb_dblocks) ||
 	    xfs_sb_validate_fsb_count(sbp, sbp->sb_rblocks)) {
 		xfs_fs_mount_cmn_err(flags,
@@ -578,27 +594,6 @@ xfs_mount_common(xfs_mount_t *mp, xfs_sb_t *sbp)
 	mp->m_blockwsize = sbp->sb_blocksize >> XFS_WORDLOG;
 	mp->m_blockwmask = mp->m_blockwsize - 1;
 
-	/*
-	 * Setup for attributes, in case they get created.
-	 * This value is for inodes getting attributes for the first time,
-	 * the per-inode value is for old attribute values.
-	 */
-	ASSERT(sbp->sb_inodesize >= 256 && sbp->sb_inodesize <= 2048);
-	switch (sbp->sb_inodesize) {
-	case 256:
-		mp->m_attroffset = XFS_LITINO(mp) -
-				   XFS_BMDR_SPACE_CALC(MINABTPTRS);
-		break;
-	case 512:
-	case 1024:
-	case 2048:
-		mp->m_attroffset = XFS_BMDR_SPACE_CALC(6 * MINABTPTRS);
-		break;
-	default:
-		ASSERT(0);
-	}
-	ASSERT(mp->m_attroffset < XFS_LITINO(mp));
-
 	mp->m_alloc_mxr[0] = xfs_allocbt_maxrecs(mp, sbp->sb_blocksize, 1);
 	mp->m_alloc_mxr[1] = xfs_allocbt_maxrecs(mp, sbp->sb_blocksize, 0);
 	mp->m_alloc_mnr[0] = mp->m_alloc_mxr[0] / 2;

fs/xfs/xfs_mount.h

@@ -276,7 +276,6 @@ typedef struct xfs_mount {
 	int			m_fixedfsid[2];	/* unchanged for life of FS */
 	uint			m_dmevmask;	/* DMI events for this FS */
 	__uint64_t		m_flags;	/* global mount flags */
-	uint			m_attroffset;	/* inode attribute offset */
 	uint			m_dir_node_ents; /* #entries in a dir danode */
 	uint			m_attr_node_ents; /* #entries in attr danode */
 	int			m_ialloc_inos;	/* inodes in inode allocation */