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From: Al Viro <viro@ftp.linux.org.uk>
To: Dave Hansen <haveblue@us.ibm.com>
Cc: akpm@osdl.org, linux-kernel@vger.kernel.org,
	herbert@13thfloor.at, serue@us.ibm.com
Subject: Re: [PATCH 20/20] honor r/w changes at do_remount() time
Date: Mon, 3 Jul 2006 18:48:04 +0100	[thread overview]
Message-ID: <20060703174804.GD29920@ftp.linux.org.uk> (raw)
In-Reply-To: <1151947814.11159.147.camel@localhost.localdomain>

On Mon, Jul 03, 2006 at 10:30:14AM -0700, Dave Hansen wrote:
> On Wed, 2006-06-28 at 06:19 +0100, Al Viro wrote:
> >         * make the moments when i_nlink hits 0 bump the superblock writers
> > count; drop it when such sucker gets freed on final iput. 
> 
> Could you elaborate on this one a bit?  
> 
> I assume that there are rules that once i_nlink hits 0, it never goes
> back up again.  It seems that a whole bunch (if not all) of the
> individual filesystems do things to it.  Is it really necessary to go
> into all of those looking for the places that i_nlink hits 0?  Seems
> like it would be an awful lot of patching.

Not that much...  That happens in three methods (->unlink(), ->rename(),
->rmdir()) and yes, we really want to track those.  Think for a minute
and you'll see why - we don't want to allow remount ro when there is
a pending truncate/freeing inode.

  reply	other threads:[~2006-07-03 17:48 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-06-27 22:14 [PATCH 00/20] Mount writer count and read-only bind mounts (v3) Dave Hansen
2006-06-27 22:14 ` [PATCH 01/20] prepare for write access checks: collapse if() Dave Hansen
2006-06-27 22:14 ` [PATCH 02/20] r/o bind mount prepwork: move open_namei()'s vfs_create() Dave Hansen
2006-06-27 22:14 ` [PATCH 03/20] Add vfsmount writer count Dave Hansen
2006-06-27 22:14 ` [PATCH 04/20] elevate mnt writers for callers of vfs_mkdir() Dave Hansen
2006-06-27 22:14 ` [PATCH 05/20] elevate write count during entire ncp_ioctl() Dave Hansen
2006-06-27 22:14 ` [PATCH 06/20] sys_symlinkat() elevate write count around vfs_symlink() Dave Hansen
2006-06-27 22:14 ` [PATCH 07/20] elevate mount count for extended attributes Dave Hansen
2006-06-27 22:14 ` [PATCH 08/20] sys_linkat(): elevate write count around vfs_link() Dave Hansen
2006-06-27 22:14 ` [PATCH 09/20] mount_is_safe(): add comment Dave Hansen
2006-06-27 22:14 ` [PATCH 10/20] unix_find_other() elevate write count for touch_atime() Dave Hansen
2006-06-27 22:14 ` [PATCH 11/20] elevate write count over calls to vfs_rename() Dave Hansen
2006-06-27 22:14 ` [PATCH 12/20] tricky: elevate write count files are open()ed Dave Hansen
2006-06-27 22:14 ` [PATCH 13/20] elevate writer count for do_sys_truncate() Dave Hansen
2006-06-27 22:14 ` [PATCH 14/20] elevate write count for do_utimes() Dave Hansen
2006-06-27 22:14 ` [PATCH 15/20] elevate write count for do_sys_utime() and touch_atime() Dave Hansen
2006-06-27 22:14 ` [PATCH 16/20] sys_mknodat(): elevate write count for vfs_mknod/create() Dave Hansen
2006-06-27 22:14 ` [PATCH 17/20] elevate mnt writers for vfs_unlink() callers Dave Hansen
2006-06-27 22:14 ` [PATCH 18/20] do_rmdir(): elevate write count Dave Hansen
2006-06-27 22:14 ` [PATCH 19/20] elevate writer count for custom 'struct file' Dave Hansen
2006-06-28  2:40   ` Andrew Morton
2006-06-28  3:59     ` Dave Hansen
2006-06-27 22:14 ` [PATCH 20/20] honor r/w changes at do_remount() time Dave Hansen
2006-06-28  5:19   ` Al Viro
2006-06-28 14:41     ` Herbert Poetzl
2006-06-28 15:01       ` Serge E. Hallyn
2006-07-03 17:30     ` Dave Hansen
2006-07-03 17:48       ` Al Viro [this message]
2006-07-03 18:23         ` Joshua Hudson
2006-07-03 18:38           ` Al Viro
2006-06-28  1:38 ` [PATCH 00/20] Mount writer count and read-only bind mounts (v3) Andrew Morton
2006-06-28  1:50   ` Dave Hansen
2006-06-28  2:17     ` Andrew Morton
2006-06-28  2:24       ` Randy.Dunlap
2006-06-28  2:30         ` Andrew Morton
2006-06-28  8:42       ` Arjan van de Ven
2006-06-28  5:56     ` Christoph Hellwig
2006-06-28 14:52     ` Herbert Poetzl

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