** Also affects: ubuntu Importance: Undecided Status: New -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1336794
Title: 9pfs does not honor open file handles on unlinked files Status in QEMU: New Status in Ubuntu: New Bug description: This was originally filed over here: https://bugzilla.redhat.com/show_bug.cgi?id=1114221 The open-unlink-fstat idiom used in some places to create an anonymous private temporary file does not work in a QEMU guest over a virtio-9p filesystem. Version-Release number of selected component (if applicable): qemu-kvm-1.6.2-6.fc20.x86_64 qemu-system-x86-1.6.2-6.fc20.x86_64 (those are fedora RPMs) How reproducible: Always. See this example C program: https://bugzilla.redhat.com/attachment.cgi?id=913069 Steps to Reproduce: 1. Export a filesystem with virt-manager for the guest. (type: mount, driver: default, mode: passthrough) 2. Start guest and mount that filesystem (mount -t 9p -o trans=virtio,version=9p2000.L ...) 3. Run a program that uses open-unlink-fstat (in my case it was trying to compile Perl 5.20) Actual results: fstat fails: open("/home/tst/filename", O_RDWR|O_CREAT|O_EXCL, 0600) = 3 unlink("/home/tst/filename") = 0 fstat(3, 0x23aa1a8) = -1 ENOENT (No such file or directory) close(3) Expected results: open("/home/tst/filename", O_RDWR|O_CREAT|O_EXCL, 0600) = 3 unlink("/home/tst/filename") = 0 fstat(3, {st_mode=S_IFREG|0600, st_size=0, ...}) = 0 fcntl(3, F_SETFD, FD_CLOEXEC) = 0 close(3) Additional info: There was a patch put into the kernel back in '07 to handle this very problem for other filesystems; maybe its helpful: http://lwn.net/Articles/251228/ There is also a thread on LKML from last December specifically about this very problem: https://lkml.org/lkml/2013/12/31/163 There was a discussion on the QEMU list back in '11 that doesn't seem to have come to a conclusion, but did provide the test program that i've attached to this report: http://marc.info/?l=qemu-devel&m=130443605720648&w=2 To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1336794/+subscriptions