On Fri, Jan 5, 2018 at 5:47 PM, Amir Goldstein <amir73il@xxxxxxxxx> wrote: > On Fri, Jan 5, 2018 at 5:43 PM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote: >> On Thu, Jan 04, 2018 at 06:40:01PM +0200, Amir Goldstein wrote: >>> Introduce the "verify" config, module and mount options. >>> >>> If the "verify" feature is enabled then overlay filesystems will use >>> the inodes index dir to verify layers consistency. >>> >>> It is possible to enable consistency verification by default during >>> build time with the OVERLAY_FS_VERIFY config option, during runtime >>> with the "verify=on" module option or on a filesystem instance basis >>> with the "verify=on" mount option. >>> >>> The "verify" feature will prevent multiple redirects to the same lower >>> dir and will prevent broken hardlinks from using the same inode number. >> >> So how does one end up with multiple redirects to same lower dir. >> >> Also what's the issue with broken hardlinks using same inode number. You >> mean lower and upper are on different fs and upper can use same inode >> number? With index=on, broken hardlink issue is taken care of so. So >> why would somebody use verify=on, which looks like will create index >> for all kind of files/dir. >> >> I have not followed this development and there is not much background >> in patch descrition or header patch, so asking all these basic questions. >> > > I have a ready answer for you :) > This is how it can happen and this is what can go wrong: > https://github.com/amir73il/xfstests/commit/f3c18125539660329195f142973ea620d6899418 > > The test duplicates a redirect dir offline with cp -a, but the > same thing can be done with a dir with origin. typo: with a non-dir with origin. > In both cases, 'diff' will wrongly report that the files/dir are the same > even though they may differ (after being copied). > > Amir. -- To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
