f2fs: fix to allow removing qf_name

[ Upstream commit ff11d8701b77e303593fd86cf9ef74ef3ac4048e ]

The mount behavior changed after commit d18535132523 ("f2fs: separate the
options parsing and options checking"), let's fix it.

[Scripts]
mkfs.f2fs -f /dev/vdb
mount -t f2fs -o usrquota /dev/vdb /mnt/f2fs
quotacheck -uc /mnt/f2fs
umount /mnt/f2fs
mount -t f2fs -o usrjquota=aquota.user,jqfmt=vfsold /dev/vdb /mnt/f2fs
mount|grep f2fs
mount -t f2fs -o remount,usrjquota=,jqfmt=vfsold /dev/vdb /mnt/f2fs
mount|grep f2fs
dmesg

[Before commit]
mount#1: ...,quota,jqfmt=vfsold,usrjquota=aquota.user,...
mount#2: ...,quota,jqfmt=vfsold,...
kmsg: no output

[After commit]
mount#1: ...,quota,jqfmt=vfsold,usrjquota=aquota.user,...
mount#2: ...,quota,jqfmt=vfsold,usrjquota=aquota.user,...
kmsg: "user quota file already specified"

[After patch]
mount#1: ...,quota,jqfmt=vfsold,usrjquota=aquota.user,...
mount#2: ...,quota,jqfmt=vfsold,...
kmsg: "remove qf_name aquota.user"

Fixes: d18535132523 ("f2fs: separate the options parsing and options checking")
Cc: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Reviewed-by: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index bf0497187bdf..8086a3456e4d 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1189,8 +1189,11 @@ static int f2fs_check_quota_consistency(struct fs_context *fc,
 				goto err_jquota_change;
 
 			if (old_qname) {
-				if (new_qname &&
-					strcmp(old_qname, new_qname) == 0) {
+				if (!new_qname) {
+					f2fs_info(sbi, "remove qf_name %s",
+								old_qname);
+					continue;
+				} else if (strcmp(old_qname, new_qname) == 0) {
 					ctx->qname_mask &= ~(1 << i);
 					continue;
 				}