[PATCH] ext4: Enable quota enforcement based on mount options

[Jan Kara <jack@suse.cz>]

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>
---
 fs/ext4/ext4.h  | 12 +++++++++---
 fs/ext4/super.c | 34 ++++++++++++++++++++++++----------
 2 files changed, 33 insertions(+), 13 deletions(-)

The patch passed xfstests both with old style and new style quotas and some
targetted manual tests so here we go... Ted please merge the patch if you
agree with it.

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index b84aa1ca480a..224cb832e2dc 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1129,9 +1129,15 @@ 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 */
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 3822a5aedc61..a03232634cd5 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1187,7 +1187,7 @@ 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,
@@ -1247,6 +1247,7 @@ 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"},
@@ -1466,8 +1467,11 @@ 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},
@@ -1756,13 +1760,17 @@ 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);
 
@@ -5129,12 +5137,18 @@ 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 "
-- 
2.6.6