On Thu, Mar 15, 2018 at 11:47 AM, Eddie Horng <eddiehorng.tw@xxxxxxxxx> wrote: > I tried to track the difference between overlay-NFSv3 and ext4-NFSv3 > of encode_post_op_attr. > mount configuration: > none /share overlay > rw,relatime,lowerdir=/base/lower,upperdir=/base/upper,workdir=/base/work,index=on,nfs_export=on > 0 0 > localhost:/share /mnt/n nfs > rw,relatime,vers=3,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=127.0.0.1,mountvers=3,mountport=40931,mountproto=udp,local_lock=none,addr=127.0.0.1 > 0 0 > /dev/loop0 /share2 ext4 rw,relatime,data=ordered 0 0 > localhost:/share2 /mnt/n2 nfs > rw,relatime,vers=3,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=127.0.0.1,mountvers=3,mountport=40931,mountproto=udp,local_lock=none,addr=127.0.0.1 > 0 0 > > file tree: > /mnt/n > |-- dirA > | `-- bar > |-- dirL > | `-- ro-file > `-- foo > > /mnt/n2 > `-- lost+found > > Attached log are dmesg start from "readdir /mnt/n (n2)" with nfs and > nfsd log are enabled all by sunrpc.nfs(d)_debug. I also add a > dump_stack() in the beginning of encode_post_op_attr. > > It seems overlay and ext4 have different call flow after "nfsd: > READDIR+", there is no failure in overlay's encode_post_op_attr, nfsd > does fill the attrs, same as ext4 but it has additional readdir call > to child node of "/". I'm not sure if this is normal to overlay and is > the cause of DT_UNKNOWN. I tried to follow nfsd readdir code to see where the difference can come from, but nothing poped at me so far. > > In additional, overlay returns DT_UNKNOWN to either lower dir or merged dir. Your test is readdir of a merged dir, the behavior could differ when readdir of an overlayfs non merged dir. Please send the output and dmesg of readdir of the non-merged lower dir: /readdir/a.out /mnt/n/dirL Please mount an NFS share of /base and send the output of the same dir: /readdir/a.out /mnt/n_base/lower/n/dirL Right now I speculate that the issue you report is related to how merged dirs are iterated, but not sure exactly why. Thanks, 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
