On Fri, 7 Aug 2009, OGAWA Hirofumi wrote:
> akpm@xxxxxxxxxxxxxxxxxxxx writes:
>
> > diff -puN fs/namei.c~vfs-fix-vfs_rename_dir-for-fs_rename_does_d_move-filesystems fs/namei.c
> > --- a/fs/namei.c~vfs-fix-vfs_rename_dir-for-fs_rename_does_d_move-filesystems
> > +++ a/fs/namei.c
> > @@ -2595,8 +2595,6 @@ static int vfs_rename_dir(struct inode *
> > if (!error)
> > target->i_flags |= S_DEAD;
> > mutex_unlock(&target->i_mutex);
> > - if (d_unhashed(new_dentry))
> > - d_rehash(new_dentry);
> > dput(new_dentry);
> > }
> > if (!error)
>
> It breaks the error handling?
>
> I.e.
>
> if (target) {
> mutex_lock(&target->i_mutex);
> dentry_unhash(new_dentry); <= unhash
> }
> if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry))
> error = -EBUSY; <= error
> else
> error = old_dir->i_op->rename(); <= or return error
> if (target) {
> if (!error)
> target->i_flags |= S_DEAD;
> mutex_unlock(&target->i_mutex);
> <= doesn't rehash
> dput(new_dentry);
> }
FWIW, the originally proposed fix only rehashed on error, but Miklos was
worried the rehash (under any circumstances) looked racy and/or bogus.
And Al was just worried. See
http://marc.info/?t=121580579500004&r=1&w=2
and
http://marc.info/?t=121664078900004&r=1&w=2
The last word from Al (about this time last year :) was
On Thu, 21 Aug 2008, Al Viro wrote:
> I'm still not convinced that this is right. Let me finish review of the
> current situation with dcache and rehashing, please. We definitely have
> problems in that area; the question is how to deal with all that crap
> without breaking exportfs *and* secondary roots a-la NFS ;-/
sage
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