Add the fs_context_operations method .reconfigure that performs
remount validation as previously done by the super_operations
.remount_fs method.
An attempt has also been made to update the comment about options
handling problems with mount(8) to reflect the current situation.
Signed-off-by: Ian Kent <raven@xxxxxxxxxx>
---
fs/xfs/xfs_super.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 68 insertions(+)
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index ddcf030cca7c..06f650fb3a8c 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1544,6 +1544,73 @@ xfs_fs_remount(
return 0;
}
+/*
+ * There can be problems with options passed from mount(8) when
+ * only the mount point path is given. The options are a merge
+ * of options from the fstab, mtab of the current mount and options
+ * given on the command line.
+ *
+ * But this can't be relied upon to accurately reflect the current
+ * mount options. Consequently rejecting options that can't be
+ * changed on reconfigure could erronously cause a mount failure.
+ *
+ * Nowadays it should be possible to compare incoming options
+ * and return an error for options that differ from the current
+ * mount and can't be changed on reconfigure.
+ *
+ * But this still might not always be the case so for now continue
+ * to return success for every reconfigure request, and silently
+ * ignore all options that can't actually be changed.
+ *
+ * See the commit log entry of this change for a more detailed
+ * desription of the problem.
+ */
+STATIC int
+xfs_reconfigure(
+ struct fs_context *fc)
+{
+ struct xfs_fs_context *ctx = fc->fs_private;
+ struct xfs_mount *mp = XFS_M(fc->root->d_sb);
+ struct xfs_mount *new_mp = fc->s_fs_info;
+ xfs_sb_t *sbp = &mp->m_sb;
+ int flags = fc->sb_flags;
+ int error;
+
+ error = xfs_validate_params(new_mp, ctx, false);
+ if (error)
+ return error;
+
+ /* inode32 -> inode64 */
+ if ((mp->m_flags & XFS_MOUNT_SMALL_INUMS) &&
+ !(new_mp->m_flags & XFS_MOUNT_SMALL_INUMS)) {
+ mp->m_flags &= ~XFS_MOUNT_SMALL_INUMS;
+ mp->m_maxagi = xfs_set_inode_alloc(mp, sbp->sb_agcount);
+ }
+
+ /* inode64 -> inode32 */
+ if (!(mp->m_flags & XFS_MOUNT_SMALL_INUMS) &&
+ (new_mp->m_flags & XFS_MOUNT_SMALL_INUMS)) {
+ mp->m_flags |= XFS_MOUNT_SMALL_INUMS;
+ mp->m_maxagi = xfs_set_inode_alloc(mp, sbp->sb_agcount);
+ }
+
+ /* ro -> rw */
+ if ((mp->m_flags & XFS_MOUNT_RDONLY) && !(flags & SB_RDONLY)) {
+ error = xfs_remount_rw(mp);
+ if (error)
+ return error;
+ }
+
+ /* rw -> ro */
+ if (!(mp->m_flags & XFS_MOUNT_RDONLY) && (flags & SB_RDONLY)) {
+ error = xfs_remount_ro(mp);
+ if (error)
+ return error;
+ }
+
+ return 0;
+}
+
/*
* Second stage of a freeze. The data is already frozen so we only
* need to take care of the metadata. Once that's done sync the superblock
@@ -2069,6 +2136,7 @@ static const struct super_operations xfs_super_operations = {
static const struct fs_context_operations xfs_context_ops = {
.parse_param = xfs_parse_param,
.get_tree = xfs_get_tree,
+ .reconfigure = xfs_reconfigure,
};
static struct file_system_type xfs_fs_type = {
