Robin Dong <hao.bigrat@xxxxxxxxx> writes: > Hi, Miklos > > We are testing and evaluating overlayfs on our machines now. It is > stable but we feel unsure about the ovl_link. > > Imaging using ext4 as upperdir which has a file "hello" and lowdir is > totally empty. > > 1. mount -t overlayfs overlayfs -o lowerdir=/lower,upperdir=/upper /overlay > 2. cd /overlay > 3. ln hello bye > > then the overlayfs code will call vfs_link to create a real ext4 > dentry for "bye" and create > a new overlayfs dentry point to overlayfs inode (which standed for > "hello"). That means: two > overlayfs dentries and only one overlayfs inode. > > now we continue > > 4. umount /overlay > 5. mount -t overlayfs overlayfs -o lowerdir=/lower,upperdir=/upper > /overlay (again) > 6. cd /overlay > 7. ls hello bye > > then the overlayfs will create two inodes(one for the "hello", another > for the "bye") and two > dentries (each point a inode).That means: two dentries and two inodes. I understand what you are saying but does this have any visible effect? I mean, is there a way to observe the difference in behavior just from userspace or the only difference is in the kernel internal objects? > As above, with different order of "create link" and "mount", the > result is not the same. > > My question is: Why not create a new overlayfs inode for "bye" and a > new overrlayfs dentry to point it when user do "ln hello bye" ? Could be done, but I'm interested in a reason for the change. Thanks, Miklos -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
