From c2ca0fcd202863b14bd041a7fece2e789926c225 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Sun, 27 Jul 2014 13:00:41 -0400 Subject: 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 Cc: stable@vger.kernel.org Signed-off-by: Al Viro --- fs/buffer.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/buffer.c b/fs/buffer.c index 3588a80854b2..c8a1c01d6187 100644 --- 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 */ -- cgit v1.2.3-58-ga151