[PATCH 01/12] quota: Allow each filesystem to specify which quota types it supports

From: Jan Kara <jack@suse.cz>
To: linux-fsdevel@vger.kernel.org
Cc: linux-ext4@vger.kernel.org, Dave Chinner <david@fromorbit.com>,
	xfs@oss.sgi.com, cluster-devel@redhat.com,
	Steven Whitehouse <swhiteho@redhat.com>,
	Mark Fasheh <mfasheh@suse.com>, Joel Becker <jlbec@evilplan.org>,
	ocfs2-devel@oss.oracle.com, reiserfs-devel@vger.kernel.org,
	Jeff Mahoney <jeffm@suse.de>, Dave Kleikamp <shaggy@kernel.org>,
	jfs-discussion@lists.sourceforge.net, tytso@mit.edu,
	viro@zeniv.linux.org.uk, Jan Kara <jack@suse.cz>
Subject: [PATCH 01/12] quota: Allow each filesystem to specify which quota types it supports
Date: Fri, 10 Oct 2014 16:54:59 +0200	[thread overview]
Message-ID: <1412952910-7142-2-git-send-email-jack@suse.cz> (raw)
In-Reply-To: <1412952910-7142-1-git-send-email-jack@suse.cz>

Currently all filesystems supporting VFS quota support user and group
quotas. With introduction of project quotas this is going to change so
make sure filesystem isn't called for quota type it doesn't support by
introduction of a bitmask determining which quota types each filesystem
supports.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/quota/quota.c      | 13 +++++++++++--
 fs/super.c            |  7 +++++++
 include/linux/quota.h |  6 ++++++
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index 75621649dbd7..0f28eac6e638 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -47,8 +47,11 @@ static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
 
 static void quota_sync_one(struct super_block *sb, void *arg)
 {
-	if (sb->s_qcop && sb->s_qcop->quota_sync)
-		sb->s_qcop->quota_sync(sb, *(int *)arg);
+	int type = *(int *)arg;
+
+	if (sb->s_qcop && sb->s_qcop->quota_sync &&
+	    (sb->s_dquot.allowed_types & (1 << type)))
+		sb->s_qcop->quota_sync(sb, type);
 }
 
 static int quota_sync_all(int type)
@@ -297,8 +300,14 @@ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
 
 	if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS))
 		return -EINVAL;
+	/*
+	 * Quota not supported on this fs? Check this before allowed_types
+	 * since they needn't be set if quota is not supported.
+	 */
 	if (!sb->s_qcop)
 		return -ENOSYS;
+	if (!(sb->s_dquot.allowed_types & (1 << type)))
+		return -EINVAL;
 
 	ret = check_quotactl_permission(sb, type, cmd, id);
 	if (ret < 0)
diff --git a/fs/super.c b/fs/super.c
index b9a214d2fe98..c6c9b2de9e31 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -215,6 +215,13 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags)
 	atomic_set(&s->s_active, 1);
 	mutex_init(&s->s_vfs_rename_mutex);
 	lockdep_set_class(&s->s_vfs_rename_mutex, &type->s_vfs_rename_key);
+	/*
+	 * For now MAXQUOTAS check in do_quotactl() will limit quota type
+	 * appropriately. When each fs sets allowed_types, we can remove the
+	 * line below
+	 */
+	s->s_dquot.allowed_types = QTYPE_MASK_USR | QTYPE_MASK_GRP |
+				   QTYPE_MASK_PRJ;
 	mutex_init(&s->s_dquot.dqio_mutex);
 	mutex_init(&s->s_dquot.dqonoff_mutex);
 	s->s_maxbytes = MAX_NON_LFS;
diff --git a/include/linux/quota.h b/include/linux/quota.h
index 80d345a3524c..b52539f42e19 100644
--- a/include/linux/quota.h
+++ b/include/linux/quota.h
@@ -56,6 +56,11 @@ enum quota_type {
 	PRJQUOTA = 2,		/* element used for project quotas */
 };
 
+/* Masks for quota types when used as a bitmask */
+#define QTYPE_MASK_USER (1 << USRQUOTA)
+#define QTYPE_MASK_GROUP (1 << GRPQUOTA)
+#define QTYPE_MASK_PROJECT (1 << PRJQUOTA)
+
 typedef __kernel_uid32_t qid_t; /* Type in which we store ids in memory */
 typedef long long qsize_t;	/* Type in which we store sizes */
 
@@ -388,6 +393,7 @@ static inline void quota_send_warning(struct kqid qid, dev_t dev,
 
 struct quota_info {
 	unsigned int flags;			/* Flags for diskquotas on this device */
+	unsigned int allowed_types;		/* Bitmask of quota types this fs supports */
 	struct mutex dqio_mutex;		/* lock device while I/O in progress */
 	struct mutex dqonoff_mutex;		/* Serialize quotaon & quotaoff */
 	struct inode *files[MAXQUOTAS];		/* inodes of quotafiles */
-- 
1.8.1.4

