Commit c2ca0fcd authored Jul 27, 2014 by Mikulas Patocka Committed by Al Viro Oct 09, 2014

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 <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

parent c35e0248

fs/buffer.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -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 */

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