Merge remote-tracking branch 'remotes/gkurz/tags/for-upstream' into staging

Merge remote-tracking branch 'remotes/gkurz/tags/for-upstream' into staging

This pull request mostly contains some more fixes to prevent buggy guests from
breaking QEMU.

# gpg: Signature made Tue 01 Nov 2016 11:26:42 GMT
# gpg:                using DSA key 0x02FC3AEB0101DBC2
# gpg: Good signature from "Greg Kurz <groug@kaod.org>"
# gpg:                 aka "Greg Kurz <groug@free.fr>"
# gpg:                 aka "Greg Kurz <gkurz@fr.ibm.com>"
# gpg:                 aka "Greg Kurz <gkurz@linux.vnet.ibm.com>"
# gpg:                 aka "Gregory Kurz (Groug) <groug@free.fr>"
# gpg:                 aka "Gregory Kurz (Cimai Technology) <gkurz@cimai.com>"
# gpg:                 aka "Gregory Kurz (Meiosys Technology) <gkurz@meiosys.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 2BD4 3B44 535E C0A7 9894  DBA2 02FC 3AEB 0101 DBC2

* remotes/gkurz/tags/for-upstream:
  9pfs: drop excessive error message from virtfs_reset()
  9pfs: don't BUG_ON() if fid is already opened
  9pfs: xattrcreate requires non-opened fids
  9pfs: limit xattr size in xattrcreate
  9pfs: fix integer overflow issue in xattr read/write
  9pfs: convert 'len/copied_len' field in V9fsXattr to the type of uint64_t
  9pfs: add xattrwalk_fid field in V9fsXattr struct

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