lkml.org 
[lkml]   [2010]   [Sep]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 09/10] VFS: Remove read-only checks from dentry_permission
From
Date
On Mon, 06 Sep 2010, NeilBrown wrote:
> It is not sufficient to depend on the the "filesystem is readonly"
> tests in dentry_permission as it does not check if the vfsmnt is
> readonly.
> All call sites already call mnt_want_write or __mnt_is_readonly which
> includes the test on MS_RDONLY.

Last time I checked I found some holes (in nfsd IIRC). That was a
long time ago and things may have changed.

That check could be replaced with a

if (IS_RDONLY(inode) &&
(S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
BUG();

which would catch these cases but only if the superblock was marked
r/o. Otherwise it's basically impossible to make sure the callers of
the VFS play by the rules. That was one reason I advocated a
path_... interface for the VFS instead of the current dentry based
one, but Al didn't like it.

Thanks,
Miklos


\
 
 \ /
  Last update: 2010-09-06 21:13    [W:0.152 / U:0.572 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site