This patch fixes the below warnings with new glibc and gcc:

hv_vss_daemon.c:100:13: warning: In the GNU C Library, "major" is defined
 by <sys/sysmacros.h>. For historical compatibility, it is currently
defined by <sys/types.h> as well, but we plan to  remove this soon.
To use "major", include <sys/sysmacros.h>  directly.

hv_fcopy_daemon.c:42:2: note: 'snprintf' output between 2 and 1040
bytes into a destination of size 260
Signed-off-by: NDexuan Cui <decui@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since a loop device is backed by a file, a backup will already result in
its parent filesystem being frozen. It's sufficient to just freeze the
parent filesystem, so we can skip the loop device.

This avoids a situation where a loop device and its parent filesystem are
both frozen and then thawed out of order. For example, if the loop device
is enumerated first, we would thaw it while its parent filesystem is still
frozen. The thaw operation fails and the loop device remains frozen.
Signed-off-by: NAlex Ng <alexng@messages.microsoft.com>
Signed-off-by: NVyronas Tsingaras <vyronas@vtsingaras.me>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If a FREEZE operation takes too long, the driver may time out and move on
to another  operation. The daemon is unaware of this and attempts to
notify the driver that the FREEZE succeeded. This results in an error from
the driver and the daemon leaves the filesystem in frozen state.

Fix this by thawing the filesystem and continuing.
Signed-off-by: NMichael Gissing <mg@faulpeltz.net>
Signed-off-by: NAlex Ng <alexng@messages.microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Hyper-V host will send a VSS_OP_HOT_BACKUP request to check if guest is
ready for a live backup/snapshot. The driver should respond to the check
only if the daemon is running and listening to requests. This allows the
host to fallback to standard snapshots in case the VSS daemon is not
running.
Signed-off-by: NAlex Ng <alexng@messages.microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix the write()'s argument in the daemon code.

Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Signed-off-by: NDexuan Cui <decui@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Introduce VSS_OP_REGISTER1 to support kernel replying to the negotiation
message with its own version.
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Tested-by: NAlex Ng <alexng@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use /dev/vmbus/hv_vss instead of netlink.
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Tested-by: NAlex Ng <alexng@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If freeze fails, vss_operate will re-enter itself to thaw. But it forgets
to call endmntent() before it recalls setmntent() again.
Signed-off-by: NVaughan Cao <vaughan.cao@oracle.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Instead of making a list of exceptions for readonly filesystems
in addition to iso9660 we already have it is better to skip freeze
operation for all readonly-mounted filesystems.
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Acked-by: NDexuan Cui <decui@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When ioctl(fd, FIFREEZE, 0) results in an error we cannot report it
to syslog instantly since that can cause write to a frozen disk.
However, the name of the filesystem which caused the error and errno
are valuable and we would like to get a nice human-readable message
in the log. Save errno before calling vss_operate(VSS_OP_THAW) and
report the error right after.

Unfortunately, FITHAW errors cannot be reported the same way as we
need to finish thawing all filesystems before calling syslog().

We should also avoid calling endmntent() for the second time in
case we encountered an error during freezing of '/' as it usually
results in SEGSEGV.
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Acked-by: NDexuan Cui <decui@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

All tools/hv daemons do mandatory daemon() on startup. However, no pidfile
is created, this make it difficult for an init system to track such daemons.
Modern linux distros use systemd as their init system. It can handle the
daemonizing by itself, however, it requires a daemon to stay in foreground
for that. Some distros already carry distro-specific patch for hv tools
which switches off daemon().

Introduce -n/--no-daemon option for all 3 daemons in hv/tools. Parse options
with getopt() to make this part easily expandable.
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If a partition appears mounted more than once in /proc/mounts, vss_do_freeze()
succeeds only for the first time and gets EBUSY (on freeze) or EINVAL (on
thaw) for the second time. The patch ignores these to make the backup feature
work.

Also improved the error handling in case a freeze operation fails.
Signed-off-by: NDexuan Cui <decui@microsoft.com>
Reviewed-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If the guest has a FAT file system mounted, skip it during the FREEZE
operation. With this change we can support host initiated backup of
the guest even when the guest may have FAT file systems mounted.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

With very old libc headers the inclusion of sys/types.h causes conflicts
with linux/types.h. Since the latter is not required anyway, remove it
from the source files. If any of the headers really needs linux/types.h
it has to include it itself.
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

send_buffer is used only once during registration. To reduce runtime
memory usage reuse the recv_buffer for registration. Also use
NLMSG_LENGTH instead of NLMSG_HDRLEN to take alignment into account.
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There is no need to have a nlmsghdr pointer to another temporary buffer.
Instead use a full struct nlmsghdr.
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

netlink_send is supposed to send just the cn_msg+hv_kvp_msg via netlink.
Currently it sets an incorrect iovec size, as reported by valgrind.

In the case of registering with the kernel the allocated buffer is large
enough to hold nlmsghdr+cn_msg+hv_kvp_msg, no overrun happens. In the
case of responding to the kernel the cn_msg is located in the middle of
recv_buffer, after the nlmsghdr. Currently the code in netlink_send adds
also the size of nlmsghdr to the payload. But nlmsghdr is a separate
iovec. This leads to an (harmless) out-of-bounds access when the kernel
processes the iovec. Correct the iovec size of the cn_msg to be just
cn_msg + its payload.
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

hv_kvp_daemon fails to start in current openSuSE 13.1 snapshots because
the kvp_send_buffer is too small to hold cn_msg+hv_kvp_msg, the very
first sendmsg returns with EFAULT. In addition it fixes the Network info
tab in Windows Server 2012R2 in SLES11.

Adjust the code in kvp and vss daemon to allocate the needed buffers at
runtime. To keep the code simple, the buffer_len includes also the
nlmsghdr, although only the recv_buffer needs this extra space.
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Check return value of setsockopt call and if it fails print error to the
system log and exit with non-zero value.
Signed-off-by: NTomas Hozza <thozza@redhat.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Check return value of poll call and if it fails print error to the
system log. If errno is EINVAL then exit with non-zero value otherwise
continue the while loop and call poll again.
Signed-off-by: NTomas Hozza <thozza@redhat.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use errno and strerror() when logging errors to provide more
information.
Signed-off-by: NTomas Hozza <thozza@redhat.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix a checkpatch warning.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

fsreeze does not work for iso9660 filesystems. A ENOSUPP may be caught
in the freeze case, but the subsequent thaw call would fail and leads to
a false error.
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As suggested by Paolo Bonzini, use ioctl instead of calling fsfreeze.
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As suggested by Paolo Bonzini, use getmntent instead of parsing output
of mount(1).
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix a checkpatch warning.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Similar to what commit 95a69ada ("tools:
hv: Netlink source address validation allows DoS") does in
hv_kvp_daemon, improve checks for origin of netlink connector message.
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This change fixes a few compile errors:

hv_vss_daemon.c:64:15: warning: unknown escape sequence '\/'
hv_vss_daemon.c:64:15: warning: unknown escape sequence '\/'
hv_vss_daemon.c: In function 'vss_operate':
hv_vss_daemon.c:66: warning: 'return' with no value, in function returning non-void
hv_vss_daemon.c: In function 'main':
hv_vss_daemon.c:130: warning: ignoring return value of 'daemon', declared with attribute warn_unused_result
hv_vss_daemon.c: In function 'vss_operate':
hv_vss_daemon.c:47: warning: 'fs_op' may be used uninitialized in this function
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This driver supports host initiated backup of the guest. On Windows guests,
the host can generate application consistent backups using the Windows VSS
framework. On Linux, we ensure that the backup will be file system consistent.
This driver allows the host to initiate a  "Freeze" operation on all the mounted
file systems in the guest. Once the mounted file systems in the guest are frozen,
the host snapshots the guest's file systems. Once this is done, the guest's file
systems are "thawed".

This driver has a user-level component (daemon) that invokes the appropriate
operation on all the mounted file systems in response to the requests from
the host. The duration for which the guest is frozen is very short - a few seconds.
During this interval, the diff disk is comitted.

In this version of the patch I have addressed the feedback from Olaf Herring.
Also, some of the connector related issues have been fixed.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>