Merge remote-tracking branch 'remotes/dgilbert-gitlab/tags/pull-virtiofs-20220217b' into staging

V3: virtiofs pull 2022-02-17

Security label improvements from Vivek
  - includes a fix for building against new kernel headers
  [V3: checkpatch style fixes]
  [V2: Fix building on old Linux]
Blocking flock disable from Sebastian
SYNCFS support from Greg

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

# gpg: Signature made Thu 17 Feb 2022 17:24:25 GMT
# gpg:                using RSA key 45F5C71B4A0CB7FB977A9FA90516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>" [full]
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A  9FA9 0516 331E BC5B FDE7

* remotes/dgilbert-gitlab/tags/pull-virtiofs-20220217b:
  virtiofsd: Add basic support for FUSE_SYNCFS request
  virtiofsd: Add an option to enable/disable security label
  virtiofsd: Create new file using O_TMPFILE and set security context
  virtiofsd: Create new file with security context
  virtiofsd: Add helpers to work with /proc/self/task/tid/attr/fscreate
  virtiofsd: Move core file creation code in separate function
  virtiofsd, fuse_lowlevel.c: Add capability to parse security context
  virtiofsd: Extend size of fuse_conn_info->capable and ->want fields
  virtiofsd: Parse extended "struct fuse_init_in"
  linux-headers: Update headers to v5.17-rc1
  virtiofsd: Fix breakage due to fuse_init_in size change
  virtiofsd: Do not support blocking flock

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>