Messages in this thread | | | Date | Wed, 5 Aug 2009 07:37:05 +0200 | From | Nick Piggin <> | Subject | Re: mnt_want_write_file() has problem? |
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On Tue, Aug 04, 2009 at 12:15:19PM -0700, Dave Hansen wrote: > On Mon, 2009-08-03 at 06:36 +0900, OGAWA Hirofumi wrote: > > diff -puN fs/namespace.c~mnt_want_write-wrong-assume fs/namespace.c > > --- > > linux-2.6/fs/namespace.c~mnt_want_write-wrong-assume 2009-08-03 > > 04:33:35.000000000 +0900 > > +++ linux-2.6-hirofumi/fs/namespace.c 2009-08-03 04:31:34.000000000 > > +0900 > > @@ -316,7 +316,8 @@ EXPORT_SYMBOL_GPL(mnt_clone_write); > > */ > > int mnt_want_write_file(struct file *file) > > { > > - if (!(file->f_mode & FMODE_WRITE)) > > + struct inode *inode = file->f_dentry->d_inode; > > + if (!(file->f_mode & FMODE_WRITE) || special_file(inode->i_mode)) > > return mnt_want_write(file->f_path.mnt); > > else > > return mnt_clone_write(file->f_path.mnt); > > I'm fine with this. I'd like a debugging check in mnt_clone_write() > since this bug is easy to detect, but such a check will also cost all of > the performance gains that Nick added. So, we can't have it > unconditionally.
Yeah, good catch, thanks for this.
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