Linux-2.6.31-rc8 inotify hangs samba clients [UPDATED]

From: Jeff Chua
Date: Fri Aug 28 2009 - 12:22:12 EST

Sorry, corrected patch below. Previous one was bad ... I was messing with.

The first part of commit 0db501bd0610ee0c0aca84d927f90bcccd09e2bd hangs WinXP clients browsing Linux samba folders ... trying to add a terminating byte to name_len. Reverting this solves the problem.

The second part of adding zeros is fine.

If we don't revert here, then Samba 3.3.7 will have to change to work with Linux 2.6.31-rc8, and perhaps other codes as well.


Here the patch to revert.

commit 0db501bd0610ee0c0aca84d927f90bcccd09e2bd
Author: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Date: Thu Aug 27 03:20:04 2009 -0700

inotify: Ensure we alwasy write the terminating NULL.

Before the rewrite copy_event_to_user always wrote a terqminating '\0'
byte to user space after the filename. Since the rewrite that
terminating byte was skipped if your filename is exactly a multiple of
event_size. Ouch!

So add one byte to name_size before we round up and use clear_user to
set userspace to zero like /dev/zero does instead of copying the
strange nul_inotify_event.

Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Eric Paris <eparis@xxxxxxxxxx>

diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index ce1f582..0e781bc 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -199,8 +196,10 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,

- /* round up event->name_len so it is a multiple of event_size */
- name_len = roundup(event->name_len, event_size);
+ /* round up event->name_len so it is a multiple of event_size
+ * plus an extra byte for the terminating '\0'.
+ */
+ name_len = roundup(event->name_len + 1, event_size);
inotify_event.len = name_len;

inotify_event.mask = inotify_mask_to_arg(event->mask);
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