From: Andrew Morton <akpm@linux-foundation.org>
To: Dave Hansen <haveblue@us.ibm.com>
Cc: linux-kernel@vger.kernel.org, hch@infradead.org
Subject: Re: [PATCH 07/25] r/o bind mounts: elevate write count for some ioctls
Date: Fri, 21 Sep 2007 01:17:06 -0700 [thread overview]
Message-ID: <20070921011706.88e9bcdd.akpm@linux-foundation.org> (raw)
In-Reply-To: <20070920195257.0E38EED5@kernel>
On Thu, 20 Sep 2007 12:52:57 -0700 Dave Hansen <haveblue@us.ibm.com> wrote:
> + ret = mnt_want_write(filp->f_vfsmnt);
It still creeps me out that we have this sprinkled *all over* the tree and
people will forget to do it and there's no runtime or compile-time checking
that they remembered to do it and when they forget to do it nobody will
notice that it broke until ages and ages later.
IOW: it is a sheer horror for maintainability.
Please have a think about what we can do about this. For example, if you'd
thought about this up-front, (and I think it's a big problem), we could
have done something grotty like, in mnt_want_write():
current->vfsmnt_im_allowed_to_write_to = inode;
and then check that current->vfsmnt_im_allowed_to_write_to is the correct
inode in __mark_inode_dirty() and various other strategic places. That
sort of thing.
We need to do *something*, I think. This code just doesn't look feasibly
maintainable to me.
next prev parent reply other threads:[~2007-09-21 8:17 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-20 19:52 [PATCH 00/25] Read-only bind mounts Dave Hansen
2007-09-20 19:52 ` [PATCH 01/25] filesystem helpers for custom 'struct file's Dave Hansen
2007-09-20 19:52 ` [PATCH 02/25] rearrange may_open() to be r/o friendly Dave Hansen
2007-09-20 19:52 ` [PATCH 03/25] give may_open() a local 'mnt' variable Dave Hansen
2007-09-20 19:57 ` Christoph Hellwig
2007-09-20 19:52 ` [PATCH 04/25] create cleanup helper svc_msnfs() Dave Hansen
2007-09-20 19:52 ` [PATCH 05/25] r/o bind mounts: stub functions Dave Hansen
2007-09-20 19:52 ` [PATCH 06/25] elevate write count open()'d files Dave Hansen
2007-11-28 8:41 ` Andrew Morton
2007-11-28 17:33 ` Dave Hansen
2007-09-20 19:52 ` [PATCH 07/25] r/o bind mounts: elevate write count for some ioctls Dave Hansen
2007-09-21 8:17 ` Andrew Morton [this message]
2007-09-21 21:15 ` Dave Hansen
2007-09-26 1:34 ` [RFC] detect missed mnt_want_write() calls Dave Hansen
2007-09-21 23:03 ` [PATCH 07/25] r/o bind mounts: elevate write count for some ioctls Andrew Morton
2007-09-21 23:39 ` Dave Hansen
2007-09-21 23:47 ` Andrew Morton
2007-09-20 19:52 ` [PATCH 08/25] elevate writer count for chown and friends Dave Hansen
2007-09-20 19:53 ` [PATCH 09/25] make access() use mnt check Dave Hansen
2007-09-20 19:53 ` [PATCH 10/25] elevate mnt writers for callers of vfs_mkdir() Dave Hansen
2007-09-20 19:53 ` [PATCH 11/25] elevate write count during entire ncp_ioctl() Dave Hansen
2007-09-20 19:53 ` [PATCH 12/25] elevate write count for link and symlink calls Dave Hansen
2007-09-20 19:53 ` [PATCH 13/25] elevate mount count for extended attributes Dave Hansen
2007-09-20 19:53 ` [PATCH 14/25] elevate write count for file_update_time() Dave Hansen
2007-09-20 19:53 ` [PATCH 15/25] unix_find_other() elevate write count for touch_atime() Dave Hansen
2007-09-20 19:53 ` [PATCH 16/25] elevate write count over calls to vfs_rename() Dave Hansen
2007-09-20 19:53 ` [PATCH 17/25] nfs: check mnt instead of superblock directly Dave Hansen
2007-09-20 19:53 ` [PATCH 18/25] elevate writer count for do_sys_truncate() Dave Hansen
2007-09-20 19:53 ` [PATCH 19/25] elevate write count for do_utimes() Dave Hansen
2007-09-20 19:53 ` [PATCH 20/25] elevate write count for do_sys_utime() and touch_atime() Dave Hansen
2007-09-20 19:53 ` [PATCH 21/25] sys_mknodat(): elevate write count for vfs_mknod/create() Dave Hansen
2007-09-20 19:53 ` [PATCH 22/25] elevate mnt writers for vfs_unlink() callers Dave Hansen
2007-09-20 19:53 ` [PATCH 23/25] do_rmdir(): elevate write count Dave Hansen
2007-09-20 19:53 ` [PATCH 24/25] r/o bind mounts: track number of mount writers Dave Hansen
2007-09-24 6:17 ` Andrew Morton
2007-09-24 14:34 ` Arjan van de Ven
2007-09-24 22:06 ` Dave Hansen
2007-09-24 22:25 ` Andrew Morton
2007-09-24 23:05 ` Dave Hansen
2007-09-24 23:15 ` Andrew Morton
2007-09-25 16:10 ` Dave Hansen
2007-09-24 17:54 ` Christoph Hellwig
2007-09-24 19:10 ` Andrew Morton
2007-09-24 19:24 ` Christoph Hellwig
2007-09-24 19:28 ` Dave Hansen
2007-09-24 19:42 ` Andrew Morton
2007-10-01 18:06 ` Dave Hansen
2007-09-20 19:53 ` [PATCH 25/25] honor r/w changes at do_remount() time Dave Hansen
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