[XFS] Fix up noattr2 so that it will properly update the versionnum and

features2 fields.

Previously, mounting with noattr2 failed to achieve anything because
although it cleared the attr2 mount flag, it would set it again as soon as
it processed the superblock fields. The fix now has an explicit noattr2
flag and uses it later to fix up the versionnum and features2 fields.

SGI-PV: 980021
SGI-Modid: xfs-linux-melb:xfs-kern:31003a

Signed-off-by: Tim Shimmin <tes@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

6 files changed, 29 insertions, 2 deletions

diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index 943381284e2..1b60e46f527 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -314,6 +314,7 @@ xfs_parseargs(
 			args->flags |= XFSMNT_ATTR2;
 		} else if (!strcmp(this_char, MNTOPT_NOATTR2)) {
 			args->flags &= ~XFSMNT_ATTR2;
+			args->flags |= XFSMNT_NOATTR2;
 		} else if (!strcmp(this_char, MNTOPT_FILESTREAM)) {
 			args->flags2 |= XFSMNT2_FILESTREAMS;
 		} else if (!strcmp(this_char, MNTOPT_NOQUOTA)) {
diff --git a/fs/xfs/xfs_clnt.h b/fs/xfs/xfs_clnt.h
index d5d1e60ee22..d2ce5dd70d8 100644
--- a/fs/xfs/xfs_clnt.h
+++ b/fs/xfs/xfs_clnt.h
@@ -78,6 +78,7 @@ struct xfs_mount_args {
 #define XFSMNT_IOSIZE		0x00002000	/* optimize for I/O size */
 #define XFSMNT_OSYNCISOSYNC	0x00004000	/* o_sync is REALLY o_sync */
 						/* (osyncisdsync is default) */
+#define XFSMNT_NOATTR2		0x00008000	/* turn off ATTR2 EA format */
 #define XFSMNT_32BITINODES	0x00200000	/* restrict inodes to 32
 						 * bits of address space */
 #define XFSMNT_GQUOTA		0x00400000	/* group quota accounting */
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index da3988453b7..361c7a755a0 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -994,9 +994,19 @@ xfs_mountfs(
 		 * Re-check for ATTR2 in case it was found in bad_features2
 		 * slot.
 		 */
-		if (xfs_sb_version_hasattr2(&mp->m_sb))
+		if (xfs_sb_version_hasattr2(&mp->m_sb) &&
+		   !(mp->m_flags & XFS_MOUNT_NOATTR2))
 			mp->m_flags |= XFS_MOUNT_ATTR2;
+	}
+
+	if (xfs_sb_version_hasattr2(&mp->m_sb) &&
+	   (mp->m_flags & XFS_MOUNT_NOATTR2)) {
+		xfs_sb_version_removeattr2(&mp->m_sb);
+		update_flags |= XFS_SB_FEATURES2;
 
+		/* update sb_versionnum for the clearing of the morebits */
+		if (!sbp->sb_features2)
+			update_flags |= XFS_SB_VERSIONNUM;
 	}
 
 	/*
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 63e0693a358..4aff0c125ad 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -378,6 +378,7 @@ typedef struct xfs_mount {
 						   counters */
 #define XFS_MOUNT_FILESTREAMS	(1ULL << 24)	/* enable the filestreams
 						   allocator */
+#define XFS_MOUNT_NOATTR2	(1ULL << 25)	/* disable use of attr2 format */
 
 
 /*
diff --git a/fs/xfs/xfs_sb.h b/fs/xfs/xfs_sb.h
index d904efe7f87..e3204a36a22 100644
--- a/fs/xfs/xfs_sb.h
+++ b/fs/xfs/xfs_sb.h
@@ -473,6 +473,13 @@ static inline void xfs_sb_version_addattr2(xfs_sb_t *sbp)
 		((sbp)->sb_features2 | XFS_SB_VERSION2_ATTR2BIT)));
 }
 
+static inline void xfs_sb_version_removeattr2(xfs_sb_t *sbp)
+{
+	sbp->sb_features2 &= ~XFS_SB_VERSION2_ATTR2BIT;
+	if (!sbp->sb_features2)
+		sbp->sb_versionnum &= ~XFS_SB_VERSION_MOREBITSBIT;
+}
+
 /*
  * end of superblock version macros
  */
diff --git a/fs/xfs/xfs_vfsops.c b/fs/xfs/xfs_vfsops.c
index 30bacd8bb0e..bbc911720d8 100644
--- a/fs/xfs/xfs_vfsops.c
+++ b/fs/xfs/xfs_vfsops.c
@@ -284,6 +284,8 @@ xfs_start_flags(
 		mp->m_flags |= XFS_MOUNT_DIRSYNC;
 	if (ap->flags & XFSMNT_ATTR2)
 		mp->m_flags |= XFS_MOUNT_ATTR2;
+	if (ap->flags & XFSMNT_NOATTR2)
+		mp->m_flags |= XFS_MOUNT_NOATTR2;
 
 	if (ap->flags2 & XFSMNT2_COMPAT_IOSIZE)
 		mp->m_flags |= XFS_MOUNT_COMPAT_IOSIZE;
@@ -346,7 +348,12 @@ xfs_finish_flags(
 		}
 	}
 
-	if (xfs_sb_version_hasattr2(&mp->m_sb))
+	/*
+	 * mkfs'ed attr2 will turn on attr2 mount unless explicitly
+	 * told by noattr2 to turn it off
+	 */
+	if (xfs_sb_version_hasattr2(&mp->m_sb) &&
+	    !(ap->flags & XFSMNT_NOATTR2))
 		mp->m_flags |= XFS_MOUNT_ATTR2;
 
 	/*