v4: - Create kset before registering virtio driver because the kset needed in virtio_fs_probe(). Solves the empty /sys/fs/virtiofs bug. [Vivek] v3: - Use dev_dbg() to avoid spamming logs [Greg] - Fix 644 mode on "tag" attr and use __ATTR_RO() [Greg] - Use kset_uevent_ops and eliminate explicit KOBJ_REMOVE [Greg] v2: - Vivek mentioned that he didn't have time to work on this patch series recently so I gave it a shot. - Information is now exposed in /sys/fs/virtiofs/ whereas before it was part of the generic virtio device kobject, which didn't really fit. Userspace needs a way to enumerate available virtiofs filesystems and detect when they are hotplugged or unplugged. This would allow systemd to wait for a virtiofs filesystem during boot, for example. This patch series adds the following in sysfs: /sys/fs/virtiofs/<n>/tag - unique identifier for mount(8) /sys/fs/virtiofs/<n>/device - symlink to virtio device A uevent is emitted when virtiofs devices are hotplugged or unplugged: KERNEL[111.113221] add /fs/virtiofs/2 (virtiofs) ACTION=add DEVPATH=/fs/virtiofs/2 SUBSYSTEM=virtiofs TAG=test KERNEL[165.527167] remove /fs/virtiofs/2 (virtiofs) ACTION=remove DEVPATH=/fs/virtiofs/2 SUBSYSTEM=virtiofs TAG=test Stefan Hajnoczi (3): virtiofs: forbid newlines in tags virtiofs: export filesystem tags through sysfs virtiofs: emit uevents on filesystem events fs/fuse/virtio_fs.c | 137 ++++++++++++++++---- Documentation/ABI/testing/sysfs-fs-virtiofs | 11 ++ 2 files changed, 126 insertions(+), 22 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-fs-virtiofs -- 2.43.0
