On Wed, Oct 09, 2019 at 07:31:19PM +0800, Ian Kent wrote:
> Add the fs_context_operations method .reconfigure that performs
> remount validation as previously done by the super_operations
> .remount_fs method.
>
> Signed-off-by: Ian Kent <raven@xxxxxxxxxx>
> ---
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
> fs/xfs/xfs_super.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 62 insertions(+)
>
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 7e634706626b..230b0e2a184c 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -1544,6 +1544,67 @@ xfs_fs_remount(
> return 0;
> }
>
> +/*
> + * Logically we would return an error here to prevent users
> + * from believing they might have changed mount options using
> + * remount which can't be changed.
> + *
> + * But unfortunately mount(8) adds all options from mtab and
> + * fstab to the mount arguments in some cases so we can't
> + * blindly reject options, but have to check for each specified
> + * option if it actually differs from the currently set option
> + * and only reject it if that's the case.
> + *
> + * Until that is implemented we return success for every remount
> + * request, and silently ignore all options that we can't actually
> + * change.
> + */
> +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 +2130,7 @@ 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 = {
>
