ext4: enable quota enforcement based on mount options

When quota information is stored in quota files, we enable only quota
accounting on mount and enforcement is enabled only in response to
Q_QUOTAON quotactl. To make ext4 behavior consistent with XFS, we add a
possibility to enable quota enforcement on mount by specifying
corresponding quota mount option (usrquota, grpquota, prjquota).

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/ext4.h

@@ -1117,9 +1117,15 @@ struct ext4_inode_info {
 #define EXT4_MOUNT_POSIX_ACL		0x08000	/* POSIX Access Control Lists */
 #define EXT4_MOUNT_NO_AUTO_DA_ALLOC	0x10000	/* No auto delalloc mapping */
 #define EXT4_MOUNT_BARRIER		0x20000 /* Use block barriers */
-#define EXT4_MOUNT_QUOTA		0x80000 /* Some quota option set */
-#define EXT4_MOUNT_USRQUOTA		0x100000 /* "old" user quota */
-#define EXT4_MOUNT_GRPQUOTA		0x200000 /* "old" group quota */
+#define EXT4_MOUNT_QUOTA		0x40000 /* Some quota option set */
+#define EXT4_MOUNT_USRQUOTA		0x80000 /* "old" user quota,
+						 * enable enforcement for hidden
+						 * quota files */
+#define EXT4_MOUNT_GRPQUOTA		0x100000 /* "old" group quota, enable
+						  * enforcement for hidden quota
+						  * files */
+#define EXT4_MOUNT_PRJQUOTA		0x200000 /* Enable project quota
+						  * enforcement */
 #define EXT4_MOUNT_DIOREAD_NOLOCK	0x400000 /* Enable support for dio read nolocking */
 #define EXT4_MOUNT_JOURNAL_CHECKSUM	0x800000 /* Journal checksums */
 #define EXT4_MOUNT_JOURNAL_ASYNC_COMMIT	0x1000000 /* Journal Async Commit */

fs/ext4/super.c

@@ -1267,7 +1267,7 @@ enum {
 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
 	Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err,
-	Opt_usrquota, Opt_grpquota, Opt_i_version, Opt_dax,
+	Opt_usrquota, Opt_grpquota, Opt_prjquota, Opt_i_version, Opt_dax,
 	Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_mblk_io_submit,
 	Opt_lazytime, Opt_nolazytime,
 	Opt_nomblk_io_submit, Opt_block_validity, Opt_noblock_validity,
@@ -1327,6 +1327,7 @@ static const match_table_t tokens = {
 	{Opt_noquota, "noquota"},
 	{Opt_quota, "quota"},
 	{Opt_usrquota, "usrquota"},
+	{Opt_prjquota, "prjquota"},
 	{Opt_barrier, "barrier=%u"},
 	{Opt_barrier, "barrier"},
 	{Opt_nobarrier, "nobarrier"},
@@ -1546,8 +1547,11 @@ static const struct mount_opts {
 							MOPT_SET | MOPT_Q},
 	{Opt_grpquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_GRPQUOTA,
 							MOPT_SET | MOPT_Q},
+	{Opt_prjquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_PRJQUOTA,
+							MOPT_SET | MOPT_Q},
 	{Opt_noquota, (EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA |
-		       EXT4_MOUNT_GRPQUOTA), MOPT_CLEAR | MOPT_Q},
+		       EXT4_MOUNT_GRPQUOTA | EXT4_MOUNT_PRJQUOTA),
+							MOPT_CLEAR | MOPT_Q},
 	{Opt_usrjquota, 0, MOPT_Q},
 	{Opt_grpjquota, 0, MOPT_Q},
 	{Opt_offusrjquota, 0, MOPT_Q},
@@ -1836,13 +1840,17 @@ static int parse_options(char *options, struct super_block *sb,
 			return 0;
 	}
 #ifdef CONFIG_QUOTA
-	if (ext4_has_feature_quota(sb) &&
-	    (test_opt(sb, USRQUOTA) || test_opt(sb, GRPQUOTA))) {
-		ext4_msg(sb, KERN_INFO, "Quota feature enabled, usrquota and grpquota "
-			 "mount options ignored.");
-		clear_opt(sb, USRQUOTA);
-		clear_opt(sb, GRPQUOTA);
-	} else if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
+	/*
+	 * We do the test below only for project quotas. 'usrquota' and
+	 * 'grpquota' mount options are allowed even without quota feature
+	 * to support legacy quotas in quota files.
+	 */
+	if (test_opt(sb, PRJQUOTA) && !ext4_has_feature_project(sb)) {
+		ext4_msg(sb, KERN_ERR, "Project quota feature not enabled. "
+			 "Cannot enable project quota enforcement.");
+		return 0;
+	}
+	if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
 		if (test_opt(sb, USRQUOTA) && sbi->s_qf_names[USRQUOTA])
 			clear_opt(sb, USRQUOTA);
 
@@ -5250,12 +5258,18 @@ static int ext4_enable_quotas(struct super_block *sb)
 		le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum),
 		le32_to_cpu(EXT4_SB(sb)->s_es->s_prj_quota_inum)
 	};
+	bool quota_mopt[EXT4_MAXQUOTAS] = {
+		test_opt(sb, USRQUOTA),
+		test_opt(sb, GRPQUOTA),
+		test_opt(sb, PRJQUOTA),
+	};
 
 	sb_dqopt(sb)->flags |= DQUOT_QUOTA_SYS_FILE;
 	for (type = 0; type < EXT4_MAXQUOTAS; type++) {
 		if (qf_inums[type]) {
 			err = ext4_quota_enable(sb, type, QFMT_VFS_V1,
-						DQUOT_USAGE_ENABLED);
+				DQUOT_USAGE_ENABLED |
+				(quota_mopt[type] ? DQUOT_LIMITS_ENABLED : 0));
 			if (err) {
 				ext4_warning(sb,
 					"Failed to enable quota tracking "