Commit eed96860 authored by Daniel P. Berrangé's avatar Daniel P. Berrangé Committed by Aneesh Kumar K.V
Browse files

hw/9pfs: Remove O_NOATIME flag from 9pfs open() calls in readonly mode 



When 2c74c2cb added support for
the 'readonly' flag against 9p filesystems, it also made QEMU
add the O_NOATIME flag as a side-effect.

The O_NOATIME flag, however, may only be set by the file owner,
or a user with CAP_FOWNER capability.  QEMU cannot assume that
this is the case for filesytems exported to QEMU.

eg, run QEMU as non-root, and attempt to pass the host OS
filesystem through to the guest OS with readonly enable.
The result is that the guest OS cannot open any files at
all.

If O_NOATIME is really required, it should be optionally
enabled via a separate QEMU command line flag.

 * hw/9pfs/virtio-9p.c: Remove O_NOATIME

Acked-by: default avatarM. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: default avatarDaniel P. Berrange <berrange@redhat.com>
Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
parent 68e59e14

hw/9pfs/virtio-9p.c

+0 −1
Original line number Diff line number Diff line
@@ -1391,7 +1391,6 @@ static void v9fs_open(void *opaque) 
                err = -EROFS;

                goto out;

            }

            flags |= O_NOATIME;

        }

        err = v9fs_co_open(pdu, fidp, flags);

        if (err < 0) {