f2fs: deallocate compressed pages when error happens

In f2fs_write_multi_pages(), f2fs_compress_pages() allocates pages for
compression work in cc->cpages[]. Then, f2fs_write_compressed_pages() initiates
bio submission. But, if there's any error before submitting the IOs like early
f2fs_cp_error(), previously it didn't free cpages by f2fs_compress_free_page().
Let's fix memory leak by putting that just before deallocating cc->cpages.

Fixes: 4c8ff709 ("f2fs: support data compression")
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/compress.c

@@ -1394,12 +1394,6 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
 
 	for (--i; i >= 0; i--)
 		fscrypt_finalize_bounce_page(&cc->cpages[i]);
-	for (i = 0; i < cc->nr_cpages; i++) {
-		if (!cc->cpages[i])
-			continue;
-		f2fs_compress_free_page(cc->cpages[i]);
-		cc->cpages[i] = NULL;
-	}
 out_put_cic:
 	kmem_cache_free(cic_entry_slab, cic);
 out_put_dnode:
@@ -1410,6 +1404,12 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
 	else
 		f2fs_unlock_op(sbi);
 out_free:
+	for (i = 0; i < cc->nr_cpages; i++) {
+		if (!cc->cpages[i])
+			continue;
+		f2fs_compress_free_page(cc->cpages[i]);
+		cc->cpages[i] = NULL;
+	}
 	page_array_free(cc->inode, cc->cpages, cc->nr_cpages);
 	cc->cpages = NULL;
 	return -EAGAIN;