[PATCH] f2fs: fix to handle quota_{on,off} correctly

[Chao Yu]

With quota_ino feature on, generic/232 reports an inconsistence issue
on the image.

The root cause is that the testcase tries to:
- use quotactl to shutdown journalled quota based on sysfile;
- and then use quotactl to enable/turn on quota based on specific file
(aquota.user or aquota.group).

Eventually, quota sysfile will be out-of-update due to following specific
file creation.

Change as below to fix this issue:
- deny enabling quota based on specific file if quota sysfile exists.
- set SBI_QUOTA_NEED_REPAIR once sysfile based quota shutdowns via
ioctl.

Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
---
 fs/f2fs/super.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index e5cae67935f6..c28d2b864975 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2000,6 +2000,12 @@ static int f2fs_quota_on(struct super_block *sb, int type, int format_id,
 	struct inode *inode;
 	int err;
 
+	/* if quota sysfile exists, deny enabling quota with specific file */
+	if (f2fs_sb_has_quota_ino(F2FS_SB(sb))) {
+		f2fs_err(F2FS_SB(sb), "quota sysfile already exists");
+		return -EBUSY;
+	}
+
 	err = f2fs_quota_sync(sb, type);
 	if (err)
 		return err;
@@ -2019,7 +2025,7 @@ static int f2fs_quota_on(struct super_block *sb, int type, int format_id,
 	return 0;
 }
 
-static int f2fs_quota_off(struct super_block *sb, int type)
+static int __f2fs_quota_off(struct super_block *sb, int type)
 {
 	struct inode *inode = sb_dqopt(sb)->files[type];
 	int err;
@@ -2045,13 +2051,30 @@ static int f2fs_quota_off(struct super_block *sb, int type)
 	return err;
 }
 
+static int f2fs_quota_off(struct super_block *sb, int type)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(sb);
+	int err;
+
+	err = __f2fs_quota_off(sb, type);
+
+	/*
+	 * quotactl can shutdown journalled quota, result in inconsistence
+	 * between quota record and fs data by following updates, tag the
+	 * flag to let fsck be aware of it.
+	 */
+	if (is_journalled_quota(sbi))
+		set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR);
+	return err;
+}
+
 void f2fs_quota_off_umount(struct super_block *sb)
 {
 	int type;
 	int err;
 
 	for (type = 0; type < MAXQUOTAS; type++) {
-		err = f2fs_quota_off(sb, type);
+		err = __f2fs_quota_off(sb, type);
 		if (err) {
 			int ret = dquot_quota_off(sb, type);
 
-- 
2.18.0.rc1