xfs: convert remaining mount flags to state flags

The remaining mount flags kept in m_flags are actually runtime state
flags. These change dynamically, so they really should be updated
atomically so we don't potentially lose an update due to racing
modifications.

Convert these remaining flags to be stored in m_opstate and use
atomic bitops to set and clear the flags. This also adds a couple of
simple wrappers for common state checks - read only and shutdown.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

1 files changed, 15 insertions, 17 deletions

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 471dba910d39..72009a3b89bb 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -250,7 +250,7 @@ xfs_fs_show_options(
  *
  * Inode allocation patterns are altered only if inode32 is requested
  * (XFS_FEAT_SMALL_INUMS), and the filesystem is sufficiently large.
- * If altered, XFS_MOUNT_32BITINODES is set as well.
+ * If altered, XFS_OPSTATE_INODE32 is set as well.
  *
  * An agcount independent of that in the mount structure is provided
  * because in the growfs case, mp->m_sb.sb_agcount is not yet updated
@@ -292,13 +292,13 @@ xfs_set_inode_alloc(
 
 	/*
 	 * If user asked for no more than 32-bit inodes, and the fs is
-	 * sufficiently large, set XFS_MOUNT_32BITINODES if we must alter
+	 * sufficiently large, set XFS_OPSTATE_INODE32 if we must alter
 	 * the allocator to accommodate the request.
 	 */
 	if (xfs_has_small_inums(mp) && ino > XFS_MAXINUMBER_32)
-		mp->m_flags |= XFS_MOUNT_32BITINODES;
+		set_bit(XFS_OPSTATE_INODE32, &mp->m_opstate);
 	else
-		mp->m_flags &= ~XFS_MOUNT_32BITINODES;
+		clear_bit(XFS_OPSTATE_INODE32, &mp->m_opstate);
 
 	for (index = 0; index < agcount; index++) {
 		struct xfs_perag	*pag;
@@ -307,7 +307,7 @@ xfs_set_inode_alloc(
 
 		pag = xfs_perag_get(mp, index);
 
-		if (mp->m_flags & XFS_MOUNT_32BITINODES) {
+		if (xfs_is_inode32(mp)) {
 			if (ino > XFS_MAXINUMBER_32) {
 				pag->pagi_inodeok = 0;
 				pag->pagf_metadata = 0;
@@ -327,7 +327,7 @@ xfs_set_inode_alloc(
 		xfs_perag_put(pag);
 	}
 
-	return (mp->m_flags & XFS_MOUNT_32BITINODES) ? maxagi : agcount;
+	return xfs_is_inode32(mp) ? maxagi : agcount;
 }
 
 STATIC int
@@ -887,7 +887,7 @@ xfs_fs_freeze(
 	 * here, so we can restart safely without racing with a stop in
 	 * xfs_fs_sync_fs().
 	 */
-	if (ret && !(mp->m_flags & XFS_MOUNT_RDONLY)) {
+	if (ret && !xfs_is_readonly(mp)) {
 		xfs_blockgc_start(mp);
 		xfs_inodegc_start(mp);
 	}
@@ -910,7 +910,7 @@ xfs_fs_unfreeze(
 	 * worker because there are no speculative preallocations on a readonly
 	 * filesystem.
 	 */
-	if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
+	if (!xfs_is_readonly(mp)) {
 		xfs_blockgc_start(mp);
 		xfs_inodegc_start(mp);
 	}
@@ -926,8 +926,6 @@ STATIC int
 xfs_finish_flags(
 	struct xfs_mount	*mp)
 {
-	int			ronly = (mp->m_flags & XFS_MOUNT_RDONLY);
-
 	/* Fail a mount where the logbuf is smaller than the log stripe */
 	if (xfs_has_logv2(mp)) {
 		if (mp->m_logbsize <= 0 &&
@@ -960,7 +958,7 @@ xfs_finish_flags(
 	/*
 	 * prohibit r/w mounts of read-only filesystems
 	 */
-	if ((mp->m_sb.sb_flags & XFS_SBF_READONLY) && !ronly) {
+	if ((mp->m_sb.sb_flags & XFS_SBF_READONLY) && !xfs_is_readonly(mp)) {
 		xfs_warn(mp,
 			"cannot mount a read-only filesystem as read-write");
 		return -EROFS;
@@ -1334,7 +1332,7 @@ xfs_fs_validate_params(
 	struct xfs_mount	*mp)
 {
 	/* No recovery flag requires a read-only mount */
-	if (xfs_has_norecovery(mp) && !(mp->m_flags & XFS_MOUNT_RDONLY)) {
+	if (xfs_has_norecovery(mp) && !xfs_is_readonly(mp)) {
 		xfs_warn(mp, "no-recovery mounts must be read-only.");
 		return -EINVAL;
 	}
@@ -1713,7 +1711,7 @@ xfs_remount_rw(
 		return -EINVAL;
 	}
 
-	mp->m_flags &= ~XFS_MOUNT_RDONLY;
+	clear_bit(XFS_OPSTATE_READONLY, &mp->m_opstate);
 
 	/*
 	 * If this is the first remount to writeable state we might have some
@@ -1801,7 +1799,7 @@ xfs_remount_ro(
 	xfs_save_resvblks(mp);
 
 	xfs_log_clean(mp);
-	mp->m_flags |= XFS_MOUNT_RDONLY;
+	set_bit(XFS_OPSTATE_READONLY, &mp->m_opstate);
 
 	return 0;
 }
@@ -1851,14 +1849,14 @@ xfs_fs_reconfigure(
 	}
 
 	/* ro -> rw */
-	if ((mp->m_flags & XFS_MOUNT_RDONLY) && !(flags & SB_RDONLY)) {
+	if (xfs_is_readonly(mp) && !(flags & SB_RDONLY)) {
 		error = xfs_remount_rw(mp);
 		if (error)
 			return error;
 	}
 
 	/* rw -> ro */
-	if (!(mp->m_flags & XFS_MOUNT_RDONLY) && (flags & SB_RDONLY)) {
+	if (!xfs_is_readonly(mp) && (flags & SB_RDONLY)) {
 		error = xfs_remount_ro(mp);
 		if (error)
 			return error;
@@ -1925,7 +1923,7 @@ static int xfs_init_fs_context(
 	 * Copy binary VFS mount flags we are interested in.
 	 */
 	if (fc->sb_flags & SB_RDONLY)
-		mp->m_flags |= XFS_MOUNT_RDONLY;
+		set_bit(XFS_OPSTATE_READONLY, &mp->m_opstate);
 	if (fc->sb_flags & SB_DIRSYNC)
 		mp->m_features |= XFS_FEAT_DIRSYNC;
 	if (fc->sb_flags & SB_SYNCHRONOUS)