[PATCH 2/3] fs: Fix hang with BSD accounting on frozen filesystem

[Jan Kara <jack@suse.cz>]

When BSD process accounting is enabled and logs information to a filesystem
which gets frozen, system easily becomes unusable because each attempt to
account process information blocks. Thus e.g. every task gets blocked in exit.

It seems better to drop accounting information (which can already happen when
filesystem is running out of space) instead of locking system up. So we
open the accounting file with O_NONBLOCK.

Reported-and-tested-by: Nikola Ciprich <nikola.ciprich@linuxbox.cz>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 kernel/acct.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/kernel/acct.c b/kernel/acct.c
index 051e071..a061116 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -201,7 +201,8 @@ static int acct_on(struct filename *pathname)
 	struct bsd_acct_struct *acct = NULL;
 
 	/* Difference from BSD - they don't do O_APPEND */
-	file = file_open_name(pathname, O_WRONLY|O_APPEND|O_LARGEFILE, 0);
+	file = file_open_name(pathname,
+			      O_WRONLY|O_APPEND|O_LARGEFILE|O_NONBLOCK, 0);
 	if (IS_ERR(file))
 		return PTR_ERR(file);
 
-- 
1.7.1