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From: Dave Hansen <haveblue@us.ibm.com>
To: Andrew Morton <akpm@osdl.org>
Cc: linux-kernel@vger.kernel.org, herbert@13thfloor.at,
	viro@ftp.linux.org.uk, serue@us.ibm.com
Subject: Re: [PATCH 19/20] elevate writer count for custom 'struct file'
Date: Tue, 27 Jun 2006 20:59:08 -0700	[thread overview]
Message-ID: <1151467148.24103.76.camel@localhost.localdomain> (raw)
In-Reply-To: <20060627194011.d485c0ec.akpm@osdl.org>

On Tue, 2006-06-27 at 19:40 -0700, Andrew Morton wrote:
> On Tue, 27 Jun 2006 15:14:56 -0700
> Dave Hansen <haveblue@us.ibm.com> wrote:
> 
> > Some filesystems forego the vfs and may_open() and create their
> > own 'struct file's.  Any of these users which set the write flag
> > on the file will cause an extra mnt_drop_write() on __fput(),
> > thus dropping the reference count too low.
> > 
> > These users tend to have artifical in-kernel vfsmounts which
> > aren't really exposed to userspace and can't be remounted, but
> > this patch is included for completeness and so that the warnings
> > don't trip over these cases.
> 
> Does the fake_file in fs/block_dev.c need similar treatment?

In practice, I think it should be OK.  The reference drop in __fput() is
only when the 'struct file' is !special_file(), which I assume all of
those block_dev.c files will be.  

I'll examine it in more detail to make sure this is true for all of the
users.

-- Dave


  reply	other threads:[~2006-06-28  3:59 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 11/20] elevate write count over calls to vfs_rename() 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 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 [this message]
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
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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