On Mon, 2 Aug 2021 at 13:49, Max Reitz <[email protected]> wrote: > On 02.08.21 12:44, Gal Hammer wrote: > > > > > > On Mon, 2 Aug 2021 at 13:36, Dr. David Alan Gilbert > > <[email protected] <mailto:[email protected]>> wrote: > > > > * Gal Hammer ([email protected] <mailto:[email protected]>) wrote: > > > Hello, > > > > > > When using NFS as a shared folder (mount type nfs4) with a Linux > > guest I > > > have the following issue: > > > > > > Guest: > > > $ ls -la /mnt/shared > > > total 8 > > > drwxr-xrwx. 2 135 135 4096 Aug 2 13:08 . > > > dr-xr-xr-x. 17 root root 224 May 23 10:58 .. > > > -rw-r--rw-. 1 135 135 27 Aug 2 13:07 readme.txt > > > > > > Host: > > > $ rm readme.txt > > > > > > Guest: > > > $ ls -la /mnt/shared > > > total 8 > > > drwxr-xrwx. 2 135 135 4096 Aug 2 13:10 . > > > dr-xr-xr-x. 17 root root 224 May 23 10:58 .. > > > -rw-r--rw-. 1 135 135 27 Aug 2 13:07 > > .nfs0000000001b600d000000005 > > > > > > Guest: > > > $ cat /mnt/shared/readme.txt > > > This is a readme.txt file. > > > > > > So it seems that the virtiofsd has a reference to the file which > > the guest > > > is not aware of and is unable to send a FUSE_FORGET message. > > This results > > > in a file not actually deleted (renamed to .nfsXXX) and is still > > accessible > > > by the guest. > > > > > > I have a similar problem when deleting a file from a Windows > > guest side. > > > The FUSE_READDIR(PLUS) commands add a reference count to files > > which the OS > > > doesn't have a file context for. However I was able to solve it > > (for now?) > > > by keeping track of returned files' inodes. > > > > > > Is this behaviour current and by design? > > > > Current problem, not really by design; the problem is the O_PATH > files > > that we have open for the inodes. I thought if the guest sent the > > forget for the file then it got closed. > > > > > > So if I understand then sending forget message for each inode returned > > by readdir won't solve the problem because you need the open files for > > inodes? > > virtiofsd internally keeps an lo_inode object for every inode that has > been looked up at some point, and every such lo_inode contains an O_PATH > fd referencing that inode. I don’t know by heart what the conditions > for dropping those lo_inode objects are. >
I think it depends on the guest's forget message. > However, once it’s possible to use file handles to reference inodes > instead of O_PATH fds (already in virtiofsd-rs, for virtiofsd there’s > this series: > https://listman.redhat.com/archives/virtio-fs/2021-July/msg00050.html), > then giving the appropriate options (-o inode_file_handles -o > modcaps=+dac_read_search) should result in no O_PATH fds being kept > around anymore, so that deleting an inode on the host will result in the > inode being truly deleted (unless the guest still has it open). > Will the guest will still need to send forget messages with this new feature? > > But with O_PATH fds, it’s kind of by design, I would say. > Thanks for the clarification. Gal. > > Max > >
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