quota: propagate error from __dquot_initialize

In commit 6184fc0b ("quota: Propagate error from ->acquire_dquot()"),
we have propagated error from __dquot_initialize to caller, but we forgot
to handle such error in add_dquot_ref(), so, currently, during quota
accounting information initialization flow, if we failed for some of
inodes, we just ignore such error, and do account for others, which is
not a good implementation.

In this patch, we choose to let user be aware of such error, so after
turning on quota successfully, we can make sure all inodes disk usage
can be accounted, which will be more reasonable.
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/quota/dquot.c

@@ -941,12 +941,13 @@ static int dqinit_needed(struct inode *inode, int type)
 }
 
 /* This routine is guarded by s_umount semaphore */
-static void add_dquot_ref(struct super_block *sb, int type)
+static int add_dquot_ref(struct super_block *sb, int type)
 {
 	struct inode *inode, *old_inode = NULL;
 #ifdef CONFIG_QUOTA_DEBUG
 	int reserved = 0;
 #endif
+	int err = 0;
 
 	spin_lock(&sb->s_inode_list_lock);
 	list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
@@ -966,7 +967,11 @@ static void add_dquot_ref(struct super_block *sb, int type)
 			reserved = 1;
 #endif
 		iput(old_inode);
-		__dquot_initialize(inode, type);
+		err = __dquot_initialize(inode, type);
+		if (err) {
+			iput(inode);
+			goto out;
+		}
 
 		/*
 		 * We hold a reference to 'inode' so it couldn't have been
@@ -981,7 +986,7 @@ static void add_dquot_ref(struct super_block *sb, int type)
 	}
 	spin_unlock(&sb->s_inode_list_lock);
 	iput(old_inode);
-
+out:
 #ifdef CONFIG_QUOTA_DEBUG
 	if (reserved) {
 		quota_error(sb, "Writes happened before quota was turned on "
@@ -989,6 +994,7 @@ static void add_dquot_ref(struct super_block *sb, int type)
 			"Please run quotacheck(8)");
 	}
 #endif
+	return err;
 }
 
 /*
@@ -2379,10 +2385,11 @@ static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
 	dqopt->flags |= dquot_state_flag(flags, type);
 	spin_unlock(&dq_state_lock);
 
-	add_dquot_ref(sb, type);
-
-	return 0;
+	error = add_dquot_ref(sb, type);
+	if (error)
+		dquot_disable(sb, type, flags);
 
+	return error;
 out_file_init:
 	dqopt->files[type] = NULL;
 	iput(inode);