qemu-io: Don't leak pattern file in error path

qemu_io_alloc_from_file() needs to close the pattern file even if some
error occurred.

Setting f = NULL in the success path and checking it for NULL in the
error path isn't strictly necessary at this point, but let's do it
anyway in case someone later adds a 'goto error' after closing the file.

Coverity: CID 1405303
Fixes: 4d731510d3
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

qemu-io-cmds.c

@@ -401,6 +401,7 @@ static void *qemu_io_alloc_from_file(BlockBackend *blk, size_t len,
     }
 
     fclose(f);
+    f = NULL;
 
     if (len > pattern_len) {
         len -= pattern_len;
@@ -420,6 +421,9 @@ static void *qemu_io_alloc_from_file(BlockBackend *blk, size_t len,
 
 error:
     qemu_io_free(buf_origin);
+    if (f) {
+        fclose(f);
+    }
     return NULL;
 }