On Fri, Jul 20, 2018 at 2:46 PM, Trond Myklebust <trondmy@xxxxxxxxxxxxxxx> wrote: > On Fri, 2018-07-20 at 14:40 -0400, Olga Kornievskaia wrote: >> On Fri, Jul 20, 2018 at 2:17 PM, Olga Kornievskaia <aglo@xxxxxxxxx> >> wrote: >> > On Fri, Jul 20, 2018 at 2:05 PM, Trond Myklebust >> > <trondmy@xxxxxxxxxxxxxxx> wrote: >> > > On Fri, 2018-07-20 at 13:26 -0400, Olga Kornievskaia wrote: >> > > > Hi Trond, >> > > > >> > > > I would some help understanding attributes management. >> > > > >> > > > Right now, any time a directory inode that was marked with >> > > > INVALID_ACCESS (say to a change_attribute changed) ends up >> > > > triggering >> > > > sending a duplicate GETATTR. I don't think that's correct. >> > > > >> > > > In nfs_execute_ok() we check if (nfs_check_cache_invalid(inode, >> > > > NFS_INO_INVALID_ACCESS)) and the call __nfs_revalidate_inode() >> > > > which >> > > > will trigger GETATTR. I don't understand why after calling this >> > > > function the INVALID_ACCESS doesn't get cleared? Because that's >> > > > what >> > > > causes the double GETATTR to be sent. >> > > > >> > > > On the open path, the first time the getattr is sent is in >> > > > >> > > > Jul 19 15:39:52 ipa18 kernel: dump_stack+0x5a/0x73 >> > > > Jul 19 15:39:52 ipa18 kernel: nfs4_proc_getattr+0x65/0x110 >> > > > [nfsv4] >> > > > Jul 19 15:39:52 ipa18 kernel: __nfs_revalidate_inode+0xe1/0x370 >> > > > [nfs] >> > > > Jul 19 15:39:52 ipa18 kernel: nfs_permission+0x16b/0x1f0 [nfs] >> > > > Jul 19 15:39:52 ipa18 kernel: inode_permission+0xab/0x130 >> > > > Jul 19 15:39:52 ipa18 kernel: link_path_walk+0x29d/0x520 >> > > > Jul 19 15:39:52 ipa18 kernel: path_openat+0xf6/0x1230 >> > > > Jul 19 15:39:52 ipa18 kernel: do_filp_open+0x91/0x100 >> > > > Jul 19 15:39:52 ipa18 kernel: do_sys_open+0x126/0x210 >> > > > Jul 19 15:39:52 ipa18 kernel: do_syscall_64+0x55/0x180 >> > > > Jul 19 15:39:52 ipa18 kernel: >> > > > entry_SYSCALL_64_after_hwframe+0x44/0xa9 >> > > > >> > > > And then again during the open >> > > > >> > > > Jul 19 15:39:52 ipa18 kernel: dump_stack+0x5a/0x73 >> > > > Jul 19 15:39:52 ipa18 kernel: nfs4_proc_getattr+0x65/0x110 >> > > > [nfsv4] >> > > > Jul 19 15:39:52 ipa18 kernel: __nfs_revalidate_inode+0xe1/0x370 >> > > > [nfs] >> > > > Jul 19 15:39:52 ipa18 kernel: nfs_permission+0x16b/0x1f0 [nfs] >> > > > Jul 19 15:39:52 ipa18 kernel: inode_permission+0xab/0x130 >> > > > Jul 19 15:39:52 ipa18 kernel: path_openat+0x942/0x1230 >> > > > Jul 19 15:39:52 ipa18 kernel: do_filp_open+0x91/0x100 >> > > > Jul 19 15:39:52 ipa18 kernel: do_sys_open+0x126/0x210 >> > > > Jul 19 15:39:52 ipa18 kernel: do_syscall_64+0x55/0x180 >> > > > Jul 19 15:39:52 ipa18 kernel: >> > > > entry_SYSCALL_64_after_hwframe+0x44/0xa9 >> > > > >> > > > Can't we remove INVALID_ACCESS after we revalidated the inode? >> > > > This >> > > > removes the duplicated GETATTRs. Is this a valid way of fixing >> > > > this >> > > > issue? >> > > > >> > > > diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c >> > > > index 8f8e9e9..2b55a45 100644 >> > > > --- a/fs/nfs/dir.c >> > > > +++ b/fs/nfs/dir.c >> > > > @@ -2504,6 +2504,8 @@ static int nfs_execute_ok(struct inode >> > > > *inode, >> > > > int mask) >> > > > if (mask & MAY_NOT_BLOCK) >> > > > return -ECHILD; >> > > > ret = __nfs_revalidate_inode(server, inode); >> > > > + if (!ret) >> > > > + NFS_I(inode)->cache_validity &= >> > > > ~NFS_INO_INVALID_ACCESS; >> > > > } >> > > > if (ret == 0 && !execute_ok(inode)) >> > > > ret = -EACCES; >> > > >> > > >> > > I don't see how the above makes sense. >> > > >> > > Either the attribute revalidation confirmed that the change attr, >> > > mode >> > > + uid + gid are unchanged, in which case the call to >> > > nfs_refresh_inode() during revalidation will fail to set >> > > NFS_INO_INVALID_ACCESS, or it confirmed that at least one of them >> > > has >> > > changed, in which case we do want to revalidate the access cache. >> > >> > I'm confused as to against what are we checking then? >> > >> > We flagged a directory inode to have invalid attributes. So we sent >> > a >> > GETATTR. I would think that after getting the result all our >> > attributes should be valid. Why would a client as the next >> > operation >> > send another GETATTR for the same inode? >> > >> >> I didn't answer your question but rather explained what I see client >> do. >> >> Let's me see if I can try again: >> in nfs_execute_ok() the check for the INVALID_CACHE is true so the >> code calls __nfs_revalidate_inode() which ends up sending a GETATTR. >> Could it be that what's happening is that GETATTRs reply for the >> change_attr is different than what we have stored. BUT that's >> obvious, >> we knew that to begin with since we are validating the attributes. So >> we update it and then we send another GETATTR now the GETATTR sends >> back the "same" change_attr and this time it matches what we have >> stored. Why is this 2nd GETATTR necessary? The attribute should be >> marked as valid after a getting a successful GETATTR. >> > Oh... I see what you are saying. Yes, that check looks like it should > be looking for NFS_INO_INVALID_OTHER. Whew. ok I'm glad something make sense. However, you lost me on "NFS_INO_INVALID_OTHER". What does that flag means? Are you talking about checking the check in nfs_execute_ok() to check for INVALID_OTHER instead of INVALID_ACCESS? > > -- > Trond Myklebust > CTO, Hammerspace Inc > 4300 El Camino Real, Suite 105 > Los Altos, CA 94022 > www.hammer.space -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
