xfs: persist quota flags with metadir

It's annoying that one has to keep reminding XFS about what quota
options it should mount with, since the quota flags recording the
previous state are sitting right there in the primary superblock.  Even
more strangely, there exists a noquota option to disable quotas
completely, so it's odder still that providing no options is the same as
noquota.

Starting with metadir, let's change the behavior so that if the user
does not specify any quota-related mount options at all, the ondisk
quota flags will be used to bring up quota.  In other words, the
filesystem will mount in the same state and with the same functionality
as it had during the last mount.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 24 insertions, 1 deletions

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 3afeab684468..20fde2442768 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -67,6 +67,9 @@ enum xfs_dax_mode {
 	XFS_DAX_NEVER = 2,
 };
 
+/* Were quota mount options provided?  Must use the upper 16 bits of qflags. */
+#define XFS_QFLAGS_MNTOPTS	(1U << 31)
+
 static void
 xfs_mount_set_dax_mode(
 	struct xfs_mount	*mp,
@@ -1264,6 +1267,8 @@ xfs_fs_parse_param(
 	int			size = 0;
 	int			opt;
 
+	BUILD_BUG_ON(XFS_QFLAGS_MNTOPTS & XFS_MOUNT_QUOTA_ALL);
+
 	opt = fs_parse(fc, xfs_fs_parameters, param, &result);
 	if (opt < 0)
 		return opt;
@@ -1341,32 +1346,39 @@ xfs_fs_parse_param(
 	case Opt_noquota:
 		parsing_mp->m_qflags &= ~XFS_ALL_QUOTA_ACCT;
 		parsing_mp->m_qflags &= ~XFS_ALL_QUOTA_ENFD;
+		parsing_mp->m_qflags |= XFS_QFLAGS_MNTOPTS;
 		return 0;
 	case Opt_quota:
 	case Opt_uquota:
 	case Opt_usrquota:
 		parsing_mp->m_qflags |= (XFS_UQUOTA_ACCT | XFS_UQUOTA_ENFD);
+		parsing_mp->m_qflags |= XFS_QFLAGS_MNTOPTS;
 		return 0;
 	case Opt_qnoenforce:
 	case Opt_uqnoenforce:
 		parsing_mp->m_qflags |= XFS_UQUOTA_ACCT;
 		parsing_mp->m_qflags &= ~XFS_UQUOTA_ENFD;
+		parsing_mp->m_qflags |= XFS_QFLAGS_MNTOPTS;
 		return 0;
 	case Opt_pquota:
 	case Opt_prjquota:
 		parsing_mp->m_qflags |= (XFS_PQUOTA_ACCT | XFS_PQUOTA_ENFD);
+		parsing_mp->m_qflags |= XFS_QFLAGS_MNTOPTS;
 		return 0;
 	case Opt_pqnoenforce:
 		parsing_mp->m_qflags |= XFS_PQUOTA_ACCT;
 		parsing_mp->m_qflags &= ~XFS_PQUOTA_ENFD;
+		parsing_mp->m_qflags |= XFS_QFLAGS_MNTOPTS;
 		return 0;
 	case Opt_gquota:
 	case Opt_grpquota:
 		parsing_mp->m_qflags |= (XFS_GQUOTA_ACCT | XFS_GQUOTA_ENFD);
+		parsing_mp->m_qflags |= XFS_QFLAGS_MNTOPTS;
 		return 0;
 	case Opt_gqnoenforce:
 		parsing_mp->m_qflags |= XFS_GQUOTA_ACCT;
 		parsing_mp->m_qflags &= ~XFS_GQUOTA_ENFD;
+		parsing_mp->m_qflags |= XFS_QFLAGS_MNTOPTS;
 		return 0;
 	case Opt_discard:
 		parsing_mp->m_features |= XFS_FEAT_DISCARD;
@@ -1433,7 +1445,8 @@ xfs_fs_validate_params(
 		return -EINVAL;
 	}
 
-	if (!IS_ENABLED(CONFIG_XFS_QUOTA) && mp->m_qflags != 0) {
+	if (!IS_ENABLED(CONFIG_XFS_QUOTA) &&
+	    (mp->m_qflags & ~XFS_QFLAGS_MNTOPTS)) {
 		xfs_warn(mp, "quota support not available in this kernel.");
 		return -EINVAL;
 	}
@@ -1768,6 +1781,14 @@ xfs_fs_fill_super(
 	if (xfs_has_parent(mp))
 		xfs_warn_experimental(mp, XFS_EXPERIMENTAL_PPTR);
 
+	/*
+	 * If no quota mount options were provided, maybe we'll try to pick
+	 * up the quota accounting and enforcement flags from the ondisk sb.
+	 */
+	if (!(mp->m_qflags & XFS_QFLAGS_MNTOPTS))
+		xfs_set_resuming_quotaon(mp);
+	mp->m_qflags &= ~XFS_QFLAGS_MNTOPTS;
+
 	error = xfs_mountfs(mp);
 	if (error)
 		goto out_filestream_unmount;
@@ -1954,6 +1975,8 @@ xfs_fs_reconfigure(
 	int			flags = fc->sb_flags;
 	int			error;
 
+	new_mp->m_qflags &= ~XFS_QFLAGS_MNTOPTS;
+
 	/* version 5 superblocks always support version counters. */
 	if (xfs_has_crc(mp))
 		fc->sb_flags |= SB_I_VERSION;