On Thu, Oct 11, 2018 at 06:49:57PM +0800, Gao Xiang wrote: > Hi Dan, > > On 2018/10/11 18:18, Dan Carpenter wrote: > > On Thu, Oct 11, 2018 at 05:46:26PM +0800, Gao Xiang wrote: > >> > >> > >> On 2018/10/11 16:44, Dan Carpenter wrote: > >>> On Tue, Oct 09, 2018 at 10:07:13PM +0800, Gao Xiang wrote: > >>>> This patch introduces inode hash function, test and set callbacks, > >>>> and iget5_locked to find the right inode for 32-bit platforms. > >>>> > >>> > >>> The way I read this changelog, we're trying to deal with corrupt file > >>> systems? Is that correct? Presumably in the current code it could lead > >>> to a Oops or something? > >> > >> No, this commit isn't trying to deal with corrupt file systems. > >> In EROFS, the nid is not continuous and it represents the inode offset > >> inode offset = nid * 32. > >> Therefore the nid is 64-bit both for 32-bit and 64-bit platforms. However, > >> i_ino is 'unsigned long', which means for 32-bit platforms, i_ino is not enough > >> to contain the nid. > >> > >> Therefore, we should use iget5_locked for this case. > > > > I guess what I'm saying is, what are the user visible effects of this > > patch? It's hard for me to tell from the patch description. Could you > > please re-write the description and send a v2? > > Sorry for my just hurry reply. It seems I really misunderstood your point :-( > > If all nids are less than 32-bit, the user will see the correct inode/nid number > for all 32-bit platforms, but if some nids are greater than 32-bit, it could be > collisions without this patch for 32-bit platforms. > > This patch switch the inode number by XOR the high 32-bit and the low 32-bit, > use customized tester to avoid collisions for 32-bit platforms. > > I will send v2 to fix the commit message...but it seems Greg is already merged in > https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git/commit/?h=staging-testing&id=2abd7814138774eb56319e9dcc0abd08ece45424 > Oh. Then that's fine then. If Greg already merged it, then it's too late to change. Thanks for the explanation, though. regards, dan carpenter _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
