On Fri, Mar 09, 2018 at 05:20:30PM +0200, Amir Goldstein wrote: > On Fri, Mar 9, 2018 at 4:44 PM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote: > > On Fri, Mar 09, 2018 at 12:34:57AM +0200, Amir Goldstein wrote: > >> On Fri, Mar 9, 2018 at 12:18 AM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote: > >> > Certain properties in ovl_lookup_data should be set only for the last > >> > element of the path. IOW, of we are calling ovl_lookup_single() for an > >> > absolute redirect, then d->is_dir and d->opaque do not make much sense > >> > for intermediate path elements. Instead set them only if dentry being > >> > lookup is last path element. > >> > >> Yeh, that's what I said, but I realized later that this is not accurate. > >> it's true for d->is_dir, but not true for d->opaque. > >> opaqueness of path elements *can* determine that the redirect result is > >> opaque, for example when redirecting to /a/b/c and /a is opaque, then > >> the resolved redirection is opaque *unless* either /a/b or /a/b/c has > >> an absolute redirect to escape the opaqueness of /a. > > > > Hi Amir, > > > > I am not sure I understand this argument about "opaque". Why opaqueness > > of parent matters to child. Can you please give an example. > > > > upper: /redirect (redirect=/a/b/c) > lower1: /a/[b]/c ([b] is opaque) > lower0: /a/b/c/foo > > upper /redirect was created by 'mv /mnt/a/b/c/ /mnt/redirect' > before rename /mnt/a/b/c did not contain 'foo' because /mnt/a/b > is not a merge dir and therefore neither is /mnt/a/b/c. > after rename /redirect should not contain 'foo' as well. > This is handles by ovl_lookup_layer() when iterating absolute > redirect element [b] d->opaque is set in the lookup state. > > The fix I sent for the case where /a/[b]/c is again an absolute > redirect (say to /a/b/c in lower0) and that *should* results in > the merge dir containing 'foo'. > > Not easy... Aha.., I get it now. So I have couple of observations. - d->opaque is still seems to be the property of last element we are searching in the path. It is d->stop which should get set for intermediate elements if we find an opaque dir in the path. In fact, ovl_lookup() does not even look at d->opaque until and unless it is set on upperdentry. Right? So if we don't set d->opaque on a lower dentry, looks like nobody will care as of now. But just to define semantics right, we can say d->opaque represents the property of last element of the path. - And apply your patch on top which will just reset d->stop = false if an absolute redirect was found in the path and leave d->opaque untouched. Does it make sense? Vivek -- 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
