exfat: fix the newly allocated clusters are not freed in error handling

In error handling 'free_cluster', before num_alloc clusters allocated,
p_chain->size will not updated and always 0, thus the newly allocated
clusters are not freed.
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

fs/exfat/fatent.c

@@ -307,7 +307,7 @@ int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
 		struct exfat_chain *p_chain, bool sync_bmap)
 {
 	int ret = -ENOSPC;
-	unsigned int num_clusters = 0, total_cnt;
+	unsigned int total_cnt;
 	unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER;
 	struct super_block *sb = inode->i_sb;
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
@@ -358,7 +358,7 @@ int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
 		if (new_clu != hint_clu &&
 		    p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 			if (exfat_chain_cont_cluster(sb, p_chain->dir,
-					num_clusters)) {
+					p_chain->size)) {
 				ret = -EIO;
 				goto free_cluster;
 			}
@@ -371,8 +371,6 @@ int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
 			goto free_cluster;
 		}
 
-		num_clusters++;
-
 		/* update FAT table */
 		if (p_chain->flags == ALLOC_FAT_CHAIN) {
 			if (exfat_ent_set(sb, new_clu, EXFAT_EOF_CLUSTER)) {
@@ -389,13 +387,14 @@ int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
 				goto free_cluster;
 			}
 		}
+		p_chain->size++;
+
 		last_clu = new_clu;
 
-		if (--num_alloc == 0) {
+		if (p_chain->size == num_alloc) {
 			sbi->clu_srch_ptr = hint_clu;
-			sbi->used_clusters += num_clusters;
+			sbi->used_clusters += num_alloc;
 
-			p_chain->size += num_clusters;
 			mutex_unlock(&sbi->bitmap_lock);
 			return 0;
 		}
@@ -406,7 +405,7 @@ int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
 
 			if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
 				if (exfat_chain_cont_cluster(sb, p_chain->dir,
-						num_clusters)) {
+						p_chain->size)) {
 					ret = -EIO;
 					goto free_cluster;
 				}
@@ -415,7 +414,6 @@ int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
 		}
 	}
 free_cluster:
-	if (num_clusters)
 	__exfat_free_cluster(inode, p_chain);
 unlock:
 	mutex_unlock(&sbi->bitmap_lock);