xfs: sparse inode chunks feature helpers and mount requirements

The sparse inode chunks feature uses the helper function to enable the
allocation of sparse inode chunks. The incompatible feature bit is set
on disk at mkfs time to prevent mount from unsupported kernels.

Also, enforce the inode alignment requirements required for sparse inode
chunks at mount time. When enabled, full inode chunks (and all inode
record) alignment is increased from cluster size to inode chunk size.
Sparse inode alignment must match the cluster size of the fs. Both
superblock alignment fields are set as such by mkfs when sparse inode
support is enabled.

Finally, warn that sparse inode chunks is an experimental feature until
further notice.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 2ce7ee3b4ec1..02f827fab829 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -725,6 +725,22 @@ xfs_mountfs(
 	}
 
 	/*
+	 * If enabled, sparse inode chunk alignment is expected to match the
+	 * cluster size. Full inode chunk alignment must match the chunk size,
+	 * but that is checked on sb read verification...
+	 */
+	if (xfs_sb_version_hassparseinodes(&mp->m_sb) &&
+	    mp->m_sb.sb_spino_align !=
+			XFS_B_TO_FSBT(mp, mp->m_inode_cluster_size)) {
+		xfs_warn(mp,
+	"Sparse inode block alignment (%u) must match cluster size (%llu).",
+			 mp->m_sb.sb_spino_align,
+			 XFS_B_TO_FSBT(mp, mp->m_inode_cluster_size));
+		error = -EINVAL;
+		goto out_remove_uuid;
+	}
+
+	/*
 	 * Set inode alignment fields
 	 */
 	xfs_set_inoalignment(mp);