Re: directory notifications lost after fork?

Stephen Rothwell (sfr@canb.auug.org.au)
Tue, 12 Mar 2002 12:04:52 +1100


Hi Andrea,

On Mon, 11 Mar 2002 11:26:52 +0100 Andrea Arcangeli <andrea@suse.de> wrote:
>
> On Sun, Mar 10, 2002 at 10:08:02PM +0100, Oskar Liljeblad wrote:
> > The code snipper demonstrates what I consider a bug in the
> > dnotify facilities in the kernel. After a fork, all registered
> > notifications are lost in the process where they originally
> > where registered (the parent process). "lost" here means that
> > the signal specified with F_SETSIG fcntl no longer is delivered
> > when notified.
>
> this should fix your problem:
>
> ftp://ftp.us.kernel.org/pub/linux/kernel/people/andrea/kernels/v2.4/2.4.19pre2aa2/00_dnotify-fl_owner-1
>
> Andrea

Can you see any reason we should not use hte patch below instead?

-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au
http://www.canb.auug.org.au/~sfr/

diff -ruN 2.4.19-pre3/fs/dnotify.c 2.4.19-pre3-notify/fs/dnotify.c --- 2.4.19-pre3/fs/dnotify.c Wed Nov 8 18:27:57 2000 +++ 2.4.19-pre3-notify/fs/dnotify.c Tue Mar 12 12:02:15 2002 @@ -1,7 +1,7 @@ /* * Directory notifications for Linux. * - * Copyright (C) 2000 Stephen Rothwell + * Copyright (C) 2000,2001,2002 Stephen Rothwell * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the @@ -59,7 +59,7 @@ write_lock(&dn_lock); prev = &inode->i_dnotify; for (odn = *prev; odn != NULL; prev = &odn->dn_next, odn = *prev) - if (odn->dn_filp == filp) + if ((odn->dn_owner == current->files) && (odn->dn_filp == filp)) break; if (odn != NULL) { if (turning_off) { @@ -82,6 +82,7 @@ dn->dn_mask = arg; dn->dn_fd = fd; dn->dn_filp = filp; + dn->dn_owner = current->files; inode->i_dnotify_mask |= arg & ~DN_MULTISHOT; dn->dn_next = inode->i_dnotify; inode->i_dnotify = dn; diff -ruN 2.4.19-pre3/include/linux/dnotify.h 2.4.19-pre3-notify/include/linux/dnotify.h --- 2.4.19-pre3/include/linux/dnotify.h Wed Mar 6 16:08:12 2002 +++ 2.4.19-pre3-notify/include/linux/dnotify.h Tue Mar 12 11:23:07 2002 @@ -11,6 +11,7 @@ see linux/fcntl.h */ int dn_fd; struct file * dn_filp; + fl_owner_t dn_owner; }; #define DNOTIFY_MAGIC 0x444E4F54 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/