[PATCH 2/2] fs: Make write(2) interruptible by a signal

[Jan Kara <jack@suse.cz>]

Currently write(2) to a file is not interruptible by a signal. Sometimes this
is desirable (e.g. when you want to quickly kill a process hogging your disk or
when some process gets blocked in balance_dirty_pages() indefinitely due to a
filesystem being in an error condition).

Reported-by: Kazuya Mio <k-mio@sx.jp.nec.com>
Tested-by: Kazuya Mio <k-mio@sx.jp.nec.com>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 mm/filemap.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index c0018f2..6b01d2f 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2407,6 +2407,10 @@ static ssize_t generic_perform_write(struct file *file,
 						iov_iter_count(i));
 
 again:
+		if (signal_pending(current)) {
+			status = -EINTR;
+			break;
+		}
 
 		/*
 		 * Bring in the user page that we will copy from _first_.
-- 
1.7.1