Using st_dev is not sufficient to uniquely identify a mount: You can
mount the same device twice, but those are still separate trees, and
e.g. by mounting something else inside one of them, they may differ.
Using statx(), we can get a mount ID that uniquely identifies a mount.
If that is available, add it to the lo_inode key.
Most of this patch is taken from Miklos's mail here:
https://marc.info/?l=fuse-devel&m=160062521827983
(virtiofsd-use-mount-id.patch attachment)
Suggested-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20201102161859.156603-5-mreitz@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
fuse_entry_param is converted to fuse_attr on the line (by
fill_entry()), so it should have a member that mirrors fuse_attr.flags.
fill_entry() should then copy this fuse_entry_param.attr_flags to
fuse_attr.flags.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20201102161859.156603-3-mreitz@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
FUSE_SUBMOUNTS is a pure indicator by the kernel to signal that it
supports submounts. It does not check its state in the init reply, so
there is nothing for fuse_lowlevel.c to do but to check its existence
and copy it into fuse_conn_info.capable.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20201102161859.156603-2-mreitz@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
The commit 88fc107956 disabled remote
posix locks by default. But the --help message still says it is enabled
by default. So fix it to output no_posix_lock.
Signed-off-by: Jiachen Zhang <zhangjiachen.jaycee@bytedance.com>
Message-Id: <20201027081558.29904-1-zhangjiachen.jaycee@bytedance.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Since commit 6f5fd83788, vu_init() can fail if malloc() returns NULL.
This fixes the following Coverity warning:
CID 1435958 (#1 of 1): Unchecked return value (CHECKED_RETURN)
Fixes: 6f5fd83788 ("libvhost-user: support many virtqueues")
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20201102092339.2034297-1-philmd@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
On ppc, and some other archs, it looks like syslog ends up using 'send'
rather than 'sendto'.
Reference: https://github.com/kata-containers/kata-containers/issues/1050
Reported-by: amulmek1@in.ibm.com
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20201102150750.34565-1-dgilbert@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This reverts the following commits due to their basis on a bogus
linux kernel header update:
c93a656f7b ("tests/acceptance: Add virtiofs_submounts.py")
45ced7ca2f ("tests/acceptance/boot_linux: Accept SSH pubkey")
08dce386e7 ("virtiofsd: Announce sub-mount points")
eba8b096c1 ("virtiofsd: Store every lo_inode's parent_dev")
ede24b6be7 ("virtiofsd: Add fuse_reply_attr_with_flags()")
e2577435d3 ("virtiofsd: Add attr_flags to fuse_entry_param")
2f10415abf ("virtiofsd: Announce FUSE_ATTR_FLAGS")
97d741cc96 ("linux/fuse.h: Pull in from Linux")
Cc: Max Reitz <mreitz@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 160385090886.20017.13382256442750027666.stgit@gimli.home
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Whenever we encounter a directory with an st_dev that differs from that
of its parent, we set the FUSE_ATTR_SUBMOUNT flag so the guest can
create a submount for it.
Make this behavior optional, so submounts are only announced to the
guest with the announce_submounts option. Some users may prefer the
current behavior, so that the guest learns nothing about the host mount
structure.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200909184028.262297-7-mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Manual merge
We want to detect mount points in the shared tree. We report them to
the guest by setting the FUSE_ATTR_SUBMOUNT flag in fuse_attr.flags, but
because the FUSE client will create a submount for every directory that
has this flag set, we must do this only for the actual mount points.
We can detect mount points by comparing a directory's st_dev with its
parent's st_dev. To be able to do so, we need to store the parent's
st_dev in the lo_inode object.
Note that mount points need not necessarily be directories; a single
file can be a mount point as well. However, for the sake of simplicity
let us ignore any non-directory mount points for now.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200909184028.262297-6-mreitz@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
The plain fuse_reply_attr() function does not allow setting
fuse_attr.flags, so add this new function that does.
Make fuse_reply_attr() a wrapper around it.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200909184028.262297-5-mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
fuse_entry_param is converted to fuse_attr on the line (by
fill_entry()), so it should have a member that mirrors fuse_attr.flags.
fill_entry() should then copy this fuse_entry_param.attr_flags to
fuse_attr.flags.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200909184028.262297-4-mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
The fuse_attr.flags field is currently just initialized to 0, which is
valid. Thus, there is no reason not to always announce FUSE_ATTR_FLAGS
(when the kernel supports it).
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200909184028.262297-3-mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
The mapping rule system implemented in the last few patches is
extremely flexible, but not easy to use. Add a simple
'map' type as a sprinkling of sugar to make it easy.
e.g.
-o xattrmap=":map::user.virtiofs.:"
would be sufficient to prefix all xattr's
or
-o xattrmap=":map:trusted.:user.virtiofs.:"
would just prefix 'trusted.' xattr's and leave
everything else alone.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20201023165812.36028-6-dgilbert@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Map xattr names coming from the server, i.e. the host filesystem;
currently this is only from listxattr.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20201023165812.36028-4-dgilbert@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Map xattr names originating at the client; from get/set/remove xattr.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20201023165812.36028-3-dgilbert@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Add an option to define mappings of xattr names so that
the client and server filesystems see different views.
This can be used to have different SELinux mappings as
seen by the guest, to run the virtiofsd with less privileges
(e.g. in a case where it can't set trusted/system/security
xattrs but you want the guest to be able to), or to isolate
multiple users of the same name; e.g. trusted attributes
used by stacking overlayfs.
A mapping engine is used with 3 simple rules; the rules can
be combined to allow most useful mapping scenarios.
The ruleset is defined by -o xattrmap='rules...'.
This patch doesn't use the rule maps yet.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20201023165812.36028-2-dgilbert@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
virtiofsd cannot run in a container because CAP_SYS_ADMIN is required to
create namespaces.
Introduce a weaker sandbox mode that is sufficient in container
environments because the container runtime already sets up namespaces.
Use chroot to restrict path traversal to the shared directory.
virtiofsd loses the following:
1. Mount namespace. The process chroots to the shared directory but
leaves the mounts in place. Seccomp rejects mount(2)/umount(2)
syscalls.
2. Pid namespace. This should be fine because virtiofsd is the only
process running in the container.
3. Network namespace. This should be fine because seccomp already
rejects the connect(2) syscall, but an additional layer of security
is lost. Container runtime-specific network security policies can be
used drop network traffic (except for the vhost-user UNIX domain
socket).
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20201008085534.16070-1-stefanha@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Just noticed that although help message says default log level is INFO,
it is actually 0 (EMRGE) and no mesage will be shown when error occurs.
It's better to follow help message.
Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Message-Id: <20201008110148.2757734-1-misono.tomohiro@jp.fujitsu.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Currently it is unknown whether virtiofsd will be built at
configuration time. It will be automatically built when dependency
is met. Also, required libraries are not clear.
To make this clear, add configure option --{enable,disable}-virtiofsd.
The default is the same as current (enabled if available) like many
other options. When --enable-virtiofsd is given and dependency is not
met, we get:
ERROR: Problem encountered: virtiofsd requires libcap-ng-devel and seccomp-devel
or
ERROR: Problem encountered: virtiofsd needs tools and vhost-user support
In addition, configuration summary now includes virtiofsd entry:
build virtiofs daemon: YES/NO
Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Message-Id: <20201008103133.2722903-1-misono.tomohiro@jp.fujitsu.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Manual merge
Since installation is not part of Makefiles anymore, Make need not
know the directories anymore. Meson already knows them through
built-in options, do everything using them instead of the config_host
dictionary.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Allow vu_message_read to be replaced by one which will make use of the
QIOChannel functions. Thus reading vhost-user message won't stall the
guest. For slave channel, we still use the default vu_message_read.
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Coiby Xu <coiby.xu@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20200918080912.321299-2-coiby.xu@gmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
In order to prevent /proc/self/fd escapes a temporary directory is
created where /proc/self/fd is bind-mounted. This doesn't work on
read-only file systems.
Avoid the temporary directory by bind-mounting /proc/self/fd over /proc.
This does not affect other processes since we remounted / with MS_REC |
MS_SLAVE. /proc must exist and virtiofsd does not use it so it's safe to
do this.
Path traversal can be tested with the following function:
static void test_proc_fd_escape(struct lo_data *lo)
{
int fd;
int level = 0;
ino_t last_ino = 0;
fd = lo->proc_self_fd;
for (;;) {
struct stat st;
if (fstat(fd, &st) != 0) {
perror("fstat");
return;
}
if (last_ino && st.st_ino == last_ino) {
fprintf(stderr, "inode number unchanged, stopping\n");
return;
}
last_ino = st.st_ino;
fprintf(stderr, "Level %d dev %lu ino %lu\n", level,
(unsigned long)st.st_dev,
(unsigned long)last_ino);
fd = openat(fd, "..", O_PATH | O_DIRECTORY | O_NOFOLLOW);
level++;
}
}
Before and after this patch only Level 0 is displayed. Without
/proc/self/fd bind-mount protection it is possible to traverse parent
directories.
Fixes: 397ae982f4 ("virtiofsd: jail lo->proc_self_fd")
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Jens Freimann <jfreimann@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20201006095826.59813-1-stefanha@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Tested-by: Jens Freimann <jfreimann@redhat.com>
Reviewed-by: Jens Freimann <jfreimann@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Since fcb4f59c87 qemu_get_local_state_pathname relies on the
init_exec_dir, and virtiofsd asserts because we never set it.
Set it.
Reported-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20201002124015.44820-1-dgilbert@redhat.com>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
If you like running QEMU as a normal user (very common for TCG runs)
but you have to run virtiofsd as a root user you run into connection
problems. Adding support for an optional --socket-group allows the
users to keep using the command line.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200925125147.26943-2-alex.bennee@linaro.org>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
dgilbert: Split long line
Gcc worries fd might be used unset, in reality it's always set if
fi is set, and only used if fi is set so it's safe. Initialise it to -1
just to keep gcc happy for now.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20200827153657.111098-2-dgilbert@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Due to the commit 65da453980, the O_DIRECT
open flag of guest applications will be discarded by virtiofsd. While
this behavior makes it consistent with the virtio-9p scheme when guest
applications use direct I/O, we no longer have any chance to bypass the
host page cache.
Therefore, we add a flag 'allow_direct_io' to lo_data. If '-o
no_allow_direct_io' option is added, or none of '-o allow_direct_io' or
'-o no_allow_direct_io' is added, the 'allow_direct_io' will be set to
0, and virtiofsd discards O_DIRECT as before. If '-o allow_direct_io'
is added to the starting command-line, 'allow_direct_io' will be set to
1, so that the O_DIRECT flags will be retained and host page cache can
be bypassed.
Signed-off-by: Jiachen Zhang <zhangjiachen.jaycee@bytedance.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200824105957.61265-1-zhangjiachen.jaycee@bytedance.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
glib offers thread pools and it seems to support "exclusive" and "shared"
thread pools.
https://developer.gnome.org/glib/stable/glib-Thread-Pools.html#g-thread-pool-new
Currently we use "exlusive" thread pools but its performance seems to be
poor. I tried using "shared" thread pools and performance seems much
better. I posted performance results here.
https://www.redhat.com/archives/virtio-fs/2020-September/msg00080.html
So lets switch to shared thread pools. We can think of making it optional
once somebody can show in what cases exclusive thread pools offer better
results. For now, my simple performance tests across the board see
better results with shared thread pools.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Message-Id: <20200921213216.GE13362@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
With seccomp fix from Miklos
When cross-compiling, by default qemu_datadir is 'c:\Program
Files\QEMU', which is not recognized as being an absolute path, and
meson will end up adding the prefix again.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20200826110419.528931-6-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
An assertion failure is raised during request processing if
unshare(CLONE_FS) fails. Implement a probe at startup so the problem can
be detected right away.
Unfortunately Docker/Moby does not include unshare in the seccomp.json
list unless CAP_SYS_ADMIN is given. Other seccomp.json lists always
include unshare (e.g. podman is unaffected):
https://raw.githubusercontent.com/seccomp/containers-golang/master/seccomp.json
Use "docker run --security-opt seccomp=path/to/seccomp.json ..." if the
default seccomp.json is missing unshare.
Cc: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200727190223.422280-4-stefanha@redhat.com>
Reviewed-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
virtiofsd does not need CAP_DAC_READ_SEARCH because it already has
the more powerful CAP_DAC_OVERRIDE. Drop it from the list of
capabilities.
This is important because container runtimes may not include
CAP_DAC_READ_SEARCH by default. This patch allows virtiofsd to reduce
its capabilities when running inside a Docker container.
Note that CAP_DAC_READ_SEARCH may be necessary again in the future if
virtiofsd starts using open_by_handle_at(2).
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20200727190223.422280-2-stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Commit 93bb3d8d4c ("virtiofsd: remove symlink fallbacks") removed
the implementation of the "norace" option, so remove it from the
cmdline help and the documentation too.
Signed-off-by: Sergio Lopez <slp@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20200717121110.50580-1-slp@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Right now we enable remote posix locks by default. That means when guest
does a posix lock it sends request to server (virtiofsd). But currently
we only support non-blocking posix lock and return -EOPNOTSUPP for
blocking version.
This means that existing applications which are doing blocking posix
locks get -EOPNOTSUPP and fail. To avoid this, people have been
running virtiosd with option "-o no_posix_lock". For new users it
is still a surprise and trial and error takes them to this option.
Given posix lock implementation is not complete in virtiofsd, disable
it by default. This means that posix locks will work with-in applications
in a guest but not across guests. Anyway we don't support sharing
filesystem among different guests yet in virtiofs so this should
not lead to any kind of surprise or regression and will make life
little easier for virtiofs users.
Reported-by: Aa Aa <jimbothom@yandex.com>
Suggested-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Allow capabilities to be added or removed from the allowed set for the
daemon; e.g.
default:
CapPrm: 00000000880000df
CapEff: 00000000880000df
-o modcaps=+sys_admin
CapPrm: 00000000882000df
CapEff: 00000000882000df
-o modcaps=+sys_admin:-chown
CapPrm: 00000000882000de
CapEff: 00000000882000de
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20200629115420.98443-4-dgilbert@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Check the capability calls worked.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Message-Id: <20200629115420.98443-3-dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
capng_updatev is a varargs function that needs a -1 to terminate it,
but it was missing.
In practice what seems to have been happening is that it's added the
capabilities we asked for, then runs into junk on the stack, so if
we're unlucky it might be adding some more, but in reality it's
failing - but after adding the capabilities we asked for.
Fixes: a59feb483b ("virtiofsd: only retain file system capabilities")
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Message-Id: <20200629115420.98443-2-dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
lo_setattr() invokes fchmod() in a rarely used code path, so it should
be whitelisted or virtiofsd will crash with EBADSYS.
Said code path can be triggered for example as follows:
On the host, in the shared directory, create a file with the sticky bit
set and a security.capability xattr:
(1) # touch foo
(2) # chmod u+s foo
(3) # setcap '' foo
Then in the guest let some process truncate that file after it has
dropped all of its capabilities (at least CAP_FSETID):
int main(int argc, char *argv[])
{
capng_setpid(getpid());
capng_clear(CAPNG_SELECT_BOTH);
capng_updatev(CAPNG_ADD, CAPNG_PERMITTED | CAPNG_EFFECTIVE, 0);
capng_apply(CAPNG_SELECT_BOTH);
ftruncate(open(argv[1], O_RDWR), 0);
}
This will cause the guest kernel to drop the sticky bit (i.e. perform a
mode change) as part of the truncate (where FATTR_FH is set), and that
will cause virtiofsd to invoke fchmod() instead of fchmodat().
(A similar configuration exists further below with futimens() vs.
utimensat(), but the former is not a syscall but just a wrapper for the
latter, so no further whitelisting is required.)
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1842667
Reported-by: Qian Cai <caiqian@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200608093111.14942-1-mreitz@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Path lookup in the kernel has special rules for looking up magic symlinks
under /proc. If a filesystem operation is instructed to follow symlinks
(e.g. via AT_SYMLINK_FOLLOW or lack of AT_SYMLINK_NOFOLLOW), and the final
component is such a proc symlink, then the target of the magic symlink is
used for the operation, even if the target itself is a symlink. I.e. path
lookup is always terminated after following a final magic symlink.
I was erronously assuming that in the above case the target symlink would
also be followed, and so workarounds were added for a couple of operations
to handle the symlink case. Since the symlink can be handled simply by
following the proc symlink, these workardouds are not needed.
Also remove the "norace" option, which disabled the workarounds.
Commit bdfd667883 ("virtiofsd: Fix xattr operations") already dealt with
the same issue for xattr operations.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Message-Id: <20200514140736.20561-1-mszeredi@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
All this process does is wait for its child. No capabilities are
needed.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
virtiofsd runs as root but only needs a subset of root's Linux
capabilities(7). As a file server its purpose is to create and access
files on behalf of a client. It needs to be able to access files with
arbitrary uid/gid owners. It also needs to be create device nodes.
Introduce a Linux capabilities(7) whitelist and drop all capabilities
that we don't need, making the virtiofsd process less powerful than a
regular uid root process.
# cat /proc/PID/status
...
Before After
CapInh: 0000000000000000 0000000000000000
CapPrm: 0000003fffffffff 00000000880000df
CapEff: 0000003fffffffff 00000000880000df
CapBnd: 0000003fffffffff 0000000000000000
CapAmb: 0000000000000000 0000000000000000
Note that file capabilities cannot be used to achieve the same effect on
the virtiofsd executable because mount is used during sandbox setup.
Therefore we drop capabilities programmatically at the right point
during startup.
This patch only affects the sandboxed child process. The parent process
that sits in waitpid(2) still has full root capabilities and will be
addressed in the next patch.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200416164907.244868-2-stefanha@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Currently, setup_mounts() bind-mounts the shared directory without
MS_REC. This makes all submounts disappear.
Pass MS_REC so that the guest can see submounts again.
Fixes: 5baa3b8e95
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200424133516.73077-1-mreitz@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Changed Fixes to point to the commit with the problem rather than
the commit that turned it on
While it's not possible to escape the proc filesystem through
lo->proc_self_fd, it is possible to escape to the root of the proc
filesystem itself through "../..".
Use a temporary mount for opening lo->proc_self_fd, that has it's root at
/proc/self/fd/, preventing access to the ancestor directories.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Message-Id: <20200429124733.22488-1-mszeredi@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
The system-wide fs.file-max sysctl value determines how many files can
be open. It defaults to a value calculated based on the machine's RAM
size. Previously virtiofsd would try to set RLIMIT_NOFILE to 1,000,000
and this allowed the FUSE client to exhaust the number of open files
system-wide on Linux hosts with less than 10 GB of RAM!
Take fs.file-max into account when choosing the default RLIMIT_NOFILE
value.
Fixes: CVE-2020-10717
Reported-by: Yuval Avrahami <yavrahami@paloaltonetworks.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20200501140644.220940-3-stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Make it possible to specify the RLIMIT_NOFILE on the command-line.
Users running multiple virtiofsd processes should allocate a certain
number to each process so that the system-wide limit can never be
exhausted.
When this option is set to 0 the rlimit is left at its current value.
This is useful when a management tool wants to configure the rlimit
itself.
The default behavior remains unchanged: try to set the limit to
1,000,000 file descriptors if the current rlimit is lower.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20200501140644.220940-2-stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
On success, the fdopendir() call closes fd. Later on the error
path we try to close an already-closed fd. This can lead to
use-after-free. Fix by only closing the fd if the fdopendir()
call failed.
Cc: qemu-stable@nongnu.org
Fixes: b39bce121b (add dirp_map to hide lo_dirp pointers)
Reported-by: Coverity (CID 1421933 USE_AFTER_FREE)
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200321120654.7985-1-philmd@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Current virtiofsd has problems about xattr operations and
they does not work properly for directory/symlink/special file.
The fundamental cause is that virtiofsd uses openat() + f...xattr()
systemcalls for xattr operation but we should not open symlink/special
file in the daemon. Therefore the function is restricted.
Fix this problem by:
1. during setup of each thread, call unshare(CLONE_FS)
2. in xattr operations (i.e. lo_getxattr), if inode is not a regular
file or directory, use fchdir(proc_loot_fd) + ...xattr() +
fchdir(root.fd) instead of openat() + f...xattr()
(Note: for a regular file/directory openat() + f...xattr()
is still used for performance reason)
With this patch, xfstests generic/062 passes on virtiofs.
This fix is suggested by Miklos Szeredi and Stefan Hajnoczi.
The original discussion can be found here:
https://www.redhat.com/archives/virtio-fs/2019-October/msg00046.html
Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Message-Id: <20200227055927.24566-3-misono.tomohiro@jp.fujitsu.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This is a cleanup patch to simplify the following xattr fix and
there is no functional changes.
- Move memory allocation to head of the function
- Unify fgetxattr/flistxattr call for both size == 0 and
size != 0 case
- Remove redundant lo_inode_put call in error path
(Note: second call is ignored now since @inode is already NULL)
Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Message-Id: <20200227055927.24566-2-misono.tomohiro@jp.fujitsu.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
All code in fuse.h and struct fuse_module are not used by virtiofsd
so removing them is safe.
Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Fix warning reported by Clang static code analyzer:
CC tools/virtiofsd/fuse_lowlevel.o
tools/virtiofsd/fuse_lowlevel.c:195:9: warning: Value stored to 'error' is never read
error = -ERANGE;
^ ~~~~~~~
Fixes: 3db2876
Reported-by: Clang Static Analyzer
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Fix warning reported by Clang static code analyzer:
CC tools/virtiofsd/passthrough_ll.o
tools/virtiofsd/passthrough_ll.c:925:9: warning: Value stored to 'newfd' is never read
newfd = -1;
^ ~~
tools/virtiofsd/passthrough_ll.c:942:9: warning: Value stored to 'newfd' is never read
newfd = -1;
^ ~~
Fixes: 7c6b66027
Reported-by: Clang Static Analyzer
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Fix warning reported by Clang static code analyzer:
CC tools/virtiofsd/passthrough_ll.o
tools/virtiofsd/passthrough_ll.c:1083:5: warning: Value stored to 'saverr' is never read
saverr = ENOMEM;
^ ~~~~~~
Fixes: 7c6b66027
Reported-by: Clang Static Analyzer
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Missing a NULL check if the argument fetch fails.
Fixes: Coverity CID 1413119
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Missing unlock in error path.
Fixes: Covertiy CID 1413123
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
If we fail when bringing up the socket we can leak the listen_fd;
in practice the daemon will exit so it's not really a problem.
Fixes: Coverity CID 1413121
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Remove fuse_req_getgroups that's unused in virtiofsd; it came in
from libfuse but we don't actually use it. It was called from
fuse_getgroups which we previously removed (but had left it's header
in).
Coverity had complained about null termination in it, but removing
it is the easiest answer.
Fixes: Coverity CID: 1413117 (String not null terminated)
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Add following options to the help message:
- cache
- flock|no_flock
- norace
- posix_lock|no_posix_lock
- readdirplus|no_readdirplus
- timeout
- writeback|no_writeback
- xattr|no_xattr
Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
dgilbert: Split cache, norace, posix_lock, readdirplus off
into our own earlier patches that added the options
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
On guest graceful shutdown, virtiofsd receives VHOST_USER_GET_VRING_BASE
request from VMM and shuts down virtqueues by calling fv_set_started(),
which joins fv_queue_thread() threads. So when virtio_loop() returns,
there should be no thread is still accessing data in fuse session and/or
virtio dev.
But on abnormal exit, e.g. guest got killed for whatever reason,
vhost-user socket is closed and virtio_loop() breaks out the main loop
and returns to main(). But it's possible fv_queue_worker()s are still
working and accessing fuse session and virtio dev, which results in
crash or use-after-free.
Fix it by stopping fv_queue_thread()s before virtio_loop() returns,
to make sure there's no-one could access fuse session and virtio dev.
Reported-by: Qingming Su <qingming.su@linux.alibaba.com>
Signed-off-by: Eryu Guan <eguan@linux.alibaba.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
lo_copy_file_range() passes -errno to fuse_reply_err() and then fuse_reply_err()
changes it to errno again, so that subsequent fuse_send_reply_iov_nofree() catches
the wrong errno.(i.e. reports "fuse: bad error value: ...").
Make fuse_send_reply_iov_nofree() accept the correct -errno by passing errno
directly in lo_copy_file_range().
Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Reviewed-by: Eryu Guan <eguan@linux.alibaba.com>
dgilbert: Sent upstream and now Merged as aa1185e153f774f1df65
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
lo_destroy was relying on some implicit knowledge of the locking;
we can avoid this if we create an unref_inode that doesn't take
the lock and then grab it for the whole of the lo_destroy.
Suggested-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Add an option to control the size of the thread pool. Requests are now
processed in parallel by default.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Now that lo_destroy() is serialized we can call unref_inode() so that
all inode resources are freed.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
When running with multiple threads it can be tricky to handle
FUSE_INIT/FUSE_DESTROY in parallel with other request types or in
parallel with themselves. Serialize FUSE_INIT and FUSE_DESTROY so that
malicious clients cannot trigger race conditions.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Introduce a thread pool so that fv_queue_thread() just pops
VuVirtqElements and hands them to the thread pool. For the time being
only one worker thread is allowed since passthrough_ll.c is not
thread-safe yet. Future patches will lift this restriction so that
multiple FUSE requests can be processed in parallel.
The main new concept is struct FVRequest, which contains both
VuVirtqElement and struct fuse_chan. We now have fv_VuDev for a device,
fv_QueueInfo for a virtqueue, and FVRequest for a request. Some of
fv_QueueInfo's fields are moved into FVRequest because they are
per-request. The name FVRequest conforms to QEMU coding style and I
expect the struct fv_* types will be renamed in a future refactoring.
This patch series is not optimal. fbuf reuse is dropped so each request
does malloc(se->bufsize), but there is no clean and cheap way to keep
this with a thread pool. The vq_lock mutex is held for longer than
necessary, especially during the eventfd_write() syscall. Performance
can be improved in the future.
prctl(2) had to be added to the seccomp whitelist because glib invokes
it.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
fuse_buf_writev() only handles the normal write in which src is buffer
and dest is fd. Specially if src buffer represents guest physical
address that can't be mapped by the daemon process, IO must be bounced
back to the VMM to do it by fuse_buf_copy().
Signed-off-by: Jun Piao <piaojun@huawei.com>
Suggested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Define fuse_buf_writev() which use pwritev and writev to improve io
bandwidth. Especially, the src bufs with 0 size should be skipped as
their mems are not *block_size* aligned which will cause writev failed
in direct io mode.
Signed-off-by: Jun Piao <piaojun@huawei.com>
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Since keep_cache(FOPEN_KEEP_CACHE) has no effect for directory as
described in fuse_common.h, use cache_readdir(FOPNE_CACHE_DIR) for
diretory open when cache=always mode.
Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
When writeback mode is enabled (-o writeback), O_APPEND handling is
done in kernel. Therefore virtiofsd clears O_APPEND flag when open.
Otherwise O_APPEND flag takes precedence over pwrite() and write
data may corrupt.
Currently clearing O_APPEND flag is done in lo_open(), but we also
need the same operation in lo_create(). So, factor out the flag
update operation in lo_open() to update_open_flags() and call it
in both lo_open() and lo_create().
This fixes the failure of xfstest generic/069 in writeback mode
(which tests O_APPEND write data integrity).
Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
If an application wants to do direct IO and opens a file with O_DIRECT
in guest, that does not necessarily mean that we need to bypass page
cache on host as well. So reset this flag on host.
If somebody needs to bypass page cache on host as well (and it is safe to
do so), we can add a knob in daemon later to control this behavior.
I check virtio-9p and they do reset O_DIRECT flag.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Eryu Guan <eguan@linux.alibaba.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Right now we always enable it regardless of given commandlines.
Fix it by setting the flag relying on the lo->flock bit.
Signed-off-by: Peng Tao <tao.peng@linux.alibaba.com>
Reviewed-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Reviewed-by: Sergio Lopez <slp@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
If thread A is using an inode it must not be deleted by thread B when
processing a FUSE_FORGET request.
The FUSE protocol itself already has a counter called nlookup that is
used in FUSE_FORGET messages. We cannot trust this counter since the
untrusted client can manipulate it via FUSE_FORGET messages.
Introduce a new refcount to keep inodes alive for the required lifespan.
lo_inode_put() must be called to release a reference. FUSE's nlookup
counter holds exactly one reference so that the inode stays alive as
long as the client still wants to remember it.
Note that the lo_inode->is_symlink field is moved to avoid creating a
hole in the struct due to struct field alignment.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Reviewed-by: Sergio Lopez <slp@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This reference counter plays a specific role in the FUSE protocol. It's
not a generic object reference counter and the FUSE kernel code calls it
"nlookup".
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Introduce lo_dirp_put() so that FUSE_RELEASEDIR does not cause
use-after-free races with other threads that are accessing lo_dirp.
Also make lo_releasedir() atomic to prevent FUSE_RELEASEDIR racing with
itself. This prevents double-frees.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Hold the lock across both lo_map_get() and lo_map_remove() to prevent
races between two FUSE_RELEASE requests. In this case I don't see a
serious bug but it's safer to do things atomically.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
We call into libvhost-user from the virtqueue handler thread and the
vhost-user message processing thread without a lock. There is nothing
protecting the virtqueue handler thread if the vhost-user message
processing thread changes the virtqueue or memory table while it is
running.
This patch introduces a read-write lock. Virtqueue handler threads are
readers. The vhost-user message processing thread is a writer. This
will allow concurrency for multiqueue in the future while protecting
against fv_queue_thread() vs virtio_loop() races.
Note that the critical sections could be made smaller but it would be
more invasive and require libvhost-user changes. Let's start simple and
improve performance later, if necessary. Another option would be an
RCU-style approach with lighter-weight primitives.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
vu_socket_path is NULL when --fd=FDNUM was used. Use
fuse_lowlevel_is_virtio() instead.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Doing posix locks with-in guest kernel are not sufficient if a file/dir
is being shared by multiple guests. So we need the notion of daemon doing
the locks which are visible to rest of the guests.
Given posix locks are per process, one can not call posix lock API on host,
otherwise bunch of basic posix locks properties are broken. For example,
If two processes (A and B) in guest open the file and take locks on different
sections of file, if one of the processes closes the fd, it will close
fd on virtiofsd and all posix locks on file will go away. This means if
process A closes the fd, then locks of process B will go away too.
Similar other problems exist too.
This patch set tries to emulate posix locks while using open file
description locks provided on Linux.
Daemon provides two options (-o posix_lock, -o no_posix_lock) to enable
or disable posix locking in daemon. By default it is enabled.
There are few issues though.
- GETLK() returns pid of process holding lock. As we are emulating locks
using OFD, and these locks are not per process and don't return pid
of process, so GETLK() in guest does not reuturn process pid.
- As of now only F_SETLK is supported and not F_SETLKW. We can't block
the thread in virtiofsd for arbitrary long duration as there is only
one thread serving the queue. That means unlock request will not make
it to daemon and F_SETLKW will block infinitely and bring virtio-fs
to a halt. This is a solvable problem though and will require significant
changes in virtiofsd and kernel. Left as a TODO item for now.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
For fuse's queueinfo, both queueinfo array and queueinfos are allocated in
fv_queue_set_started() but not cleaned up when the daemon process quits.
This fixes the leak in proper places.
Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
Signed-off-by: Eric Ren <renzhen@linux.alibaba.com>
Reviewed-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Eric Ren <renzhen@linux.alibaba.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
lookup is a RO operations, PARALLEL_DIROPS can be enabled.
Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
virtiofsd can run multiply even if the vhost_user_socket is same path.
]# ./virtiofsd -o vhost_user_socket=/tmp/vhostqemu -o source=/tmp/share &
[1] 244965
virtio_session_mount: Waiting for vhost-user socket connection...
]# ./virtiofsd -o vhost_user_socket=/tmp/vhostqemu -o source=/tmp/share &
[2] 244966
virtio_session_mount: Waiting for vhost-user socket connection...
]#
The user will get confused about the situation and maybe the cause of the
unexpected problem. So it's better to prevent the multiple running.
Create a regular file under localstatedir directory to exclude the
vhost_user_socket. To create and lock the file, use qemu_write_pidfile()
because the API has some sanity checks and file lock.
Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Applied fixes from Stefan's review and moved osdep include
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This offers an helper function for lo_data's cleanup.
Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
valgrind reported that lo.source is leaked on quiting, but it was defined
as (const char*) as it may point to a const string "/".
Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This cleans up unfreed resources in se on quiting, including
se->virtio_dev, se->vu_socket_path, se->vu_socketfd.
Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Neither fuse_parse_cmdline() nor fuse_opt_parse() goes to the right place
to do cleanup.
Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Define HAVE_STRUCT_STAT_ST_ATIM to 1 if `st_atim' is member of `struct
stat' which means support nanosecond resolution for the file timestamp
fields.
Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Clear out our inodes and fd's on a 'destroy' - so we get rid
of them if we reboot the guest.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Improve performance of inode lookup by using a hash table.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
- Rename "cache=never" to "cache=none" to match 9p's similar option.
- Rename CACHE_NORMAL constant to CACHE_AUTO to match the "cache=auto"
option.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Inititialize the root inode in a single place.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
dgilbert:
with fix suggested by Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Reviewed-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
The Linux file handle APIs (struct export_operations) can access inodes
that are not attached to parents because path name traversal is not
performed. Refuse if there is no parent in lo_do_lookup().
Also clean up lo_do_lookup() while we're here.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
...because the attributes sent in the READDIRPLUS reply would be discarded
anyway.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Kill the threads we've started when the queues get stopped.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
With improvements by:
Signed-off-by: Eryu Guan <eguan@linux.alibaba.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Handle a
mount
hard reboot (without unmount)
mount
we get another 'init' which FUSE doesn't normally expect.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
