fs: make cont_expand_zero interruptible

This patch makes it possible to kill a process looping in cont_expand_zero. A process may spend a lot of time in this function, so it is desirable to be able to kill it. It happened to me that I wanted to copy a piece data from the disk to a file. By mistake, I used the "seek" parameter to dd instead of "skip". Due to the "seek" parameter, dd attempted to extend the file and became stuck doing so - the only possibility was to reset the machine or wait many hours until the filesystem runs out of space and cont_expand_zero fails. We need this patch to be able to terminate the process. Signed-off-by: Mikulas Patocka <[email protected]> Cc: [email protected] Signed-off-by: Al Viro <[email protected]>
maraz · Oct 9, 2014 · c2ca0fc · c2ca0fc
1 parent c35e024
commit c2ca0fc
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/fs/buffer.c b/fs/buffer.c
@@ -2318,6 +2318,11 @@ static int cont_expand_zero(struct file *file, struct address_space *mapping,
 		err = 0;
 
 		balance_dirty_pages_ratelimited(mapping);
+
+		if (unlikely(fatal_signal_pending(current))) {
+			err = -EINTR;
+			goto out;
+		}
 	}
 
 	/* page covers the boundary, find the boundary offset */