Normal, synchronous requests will have their args allocated on the stack.
After the FR_FINISHED bit is set by receiving the reply from the userspace
fuse server, the originating task may return and reuse the stack frame,
resulting in an Oops if the args structure is dereferenced.
Fix by setting a flag in the request itself upon initializing, indicating
whether it has an asynchronous ->end() callback.
Reported-by: Kyle Sanderson <kyle.leet@gmail.com>
Reported-by: Michael Stapelberg <michael+lkml@stapelberg.ch>
Fixes: 2b319d1f6f ("fuse: don't dereference req->args on finished request")
Cc: <stable@vger.kernel.org> # v5.4
Tested-by: Michael Stapelberg <michael+lkml@stapelberg.ch>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Pull vfs file system parameter updates from Al Viro:
"Saner fs_parser.c guts and data structures. The system-wide registry
of syntax types (string/enum/int32/oct32/.../etc.) is gone and so is
the horror switch() in fs_parse() that would have to grow another case
every time something got added to that system-wide registry.
New syntax types can be added by filesystems easily now, and their
namespace is that of functions - not of system-wide enum members. IOW,
they can be shared or kept private and if some turn out to be widely
useful, we can make them common library helpers, etc., without having
to do anything whatsoever to fs_parse() itself.
And we already get that kind of requests - the thing that finally
pushed me into doing that was "oh, and let's add one for timeouts -
things like 15s or 2h". If some filesystem really wants that, let them
do it. Without somebody having to play gatekeeper for the variants
blessed by direct support in fs_parse(), TYVM.
Quite a bit of boilerplate is gone. And IMO the data structures make a
lot more sense now. -200LoC, while we are at it"
* 'merge.nfs-fs_parse.1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (25 commits)
tmpfs: switch to use of invalfc()
cgroup1: switch to use of errorfc() et.al.
procfs: switch to use of invalfc()
hugetlbfs: switch to use of invalfc()
cramfs: switch to use of errofc() et.al.
gfs2: switch to use of errorfc() et.al.
fuse: switch to use errorfc() et.al.
ceph: use errorfc() and friends instead of spelling the prefix out
prefix-handling analogues of errorf() and friends
turn fs_param_is_... into functions
fs_parse: handle optional arguments sanely
fs_parse: fold fs_parameter_desc/fs_parameter_spec
fs_parser: remove fs_parameter_description name field
add prefix to fs_context->log
ceph_parse_param(), ceph_parse_mon_ips(): switch to passing fc_log
new primitive: __fs_parse()
switch rbd and libceph to p_log-based primitives
struct p_log, variants of warnf() et.al. taking that one instead
teach logfc() to handle prefices, give it saner calling conventions
get rid of cg_invalf()
...
Unused now.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Fixes coccicheck warning:
fs/fuse/readdir.c:335:1-19: WARNING: Assignment of 0/1 to bool variable
fs/fuse/file.c:1398:2-19: WARNING: Assignment of 0/1 to bool variable
fs/fuse/file.c:1400:2-20: WARNING: Assignment of 0/1 to bool variable
fs/fuse/cuse.c:454:1-20: WARNING: Assignment of 0/1 to bool variable
fs/fuse/cuse.c:455:1-19: WARNING: Assignment of 0/1 to bool variable
fs/fuse/inode.c:497:2-17: WARNING: Assignment of 0/1 to bool variable
fs/fuse/inode.c:504:2-23: WARNING: Assignment of 0/1 to bool variable
fs/fuse/inode.c:511:2-22: WARNING: Assignment of 0/1 to bool variable
fs/fuse/inode.c:518:2-23: WARNING: Assignment of 0/1 to bool variable
fs/fuse/inode.c:522:2-26: WARNING: Assignment of 0/1 to bool variable
fs/fuse/inode.c:526:2-18: WARNING: Assignment of 0/1 to bool variable
fs/fuse/inode.c:1000:1-20: WARNING: Assignment of 0/1 to bool variable
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Allow fuse to pass RENAME_WHITEOUT to fuse server. Overlayfs on top of
virtiofs uses RENAME_WHITEOUT.
Without this patch renaming a directory in overlayfs (dir is on lower)
fails with -EINVAL. With this patch it works.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Handle the special case of fuse_readpages() wanting to read the last page
of a hugest file possible and overflowing the end offset in the process.
This is basically to unbreak xfstests:generic/525 and prevent filesystems
from doing bad things with an overflowing offset.
Reported-by: Xiao Yang <ice_yangxiao@163.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
fuse_direct_io() can end up advancing the iterator by more than the amount
of data read or written. This case is handled by the generic code if going
through ->direct_IO(), but not in the FOPEN_DIRECT_IO case.
Fix by reverting the extra bytes from the iterator in case of error or a
short count.
To test: install lxcfs, then the following testcase
int fd = open("/var/lib/lxcfs/proc/uptime", O_RDONLY);
sendfile(1, fd, NULL, 16777216);
sendfile(1, fd, NULL, 16777216);
will spew WARN_ON() in iov_iter_pipe().
Reported-by: Peter Geis <pgwipeout@gmail.com>
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Fixes: 3c3db095b6 ("fuse: use iov_iter based generic splice helpers")
Cc: <stable@vger.kernel.org> # v5.1
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Buffered read in fuse normally goes via:
-> generic_file_buffered_read()
-> fuse_readpages()
-> fuse_send_readpages()
->fuse_simple_request() [called since v5.4]
In the case of a read request, fuse_simple_request() will return a
non-negative bytecount on success or a negative error value. A positive
bytecount was taken to be an error and the PG_error flag set on the page.
This resulted in generic_file_buffered_read() falling back to ->readpage(),
which would repeat the read request and succeed. Because of the repeated
read succeeding the bug was not detected with regression tests or other use
cases.
The FTP module in GVFS however fails the second read due to the
non-seekable nature of FTP downloads.
Fix by checking and ignoring positive return value from
fuse_simple_request().
Reported-by: Ondrej Holy <oholy@redhat.com>
Link: https://gitlab.gnome.org/GNOME/gvfs/issues/441
Fixes: 134831e36b ("fuse: convert readpages to simple api")
Cc: <stable@vger.kernel.org> # v5.4
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fix the iteration end check in fuse_dev_splice_write(). The iterator
position can only be compared with == or != since wrappage may be involved.
Fixes: 8cefc107ca ("pipe: Use head and tail pointers for the ring, not cursor and length")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Merge tag 'fuse-update-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
Pull fuse update from Miklos Szeredi:
- Fix a regression introduced in the last release
- Fix a number of issues with validating data coming from userspace
- Some cleanups in virtiofs
* tag 'fuse-update-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: fix Kconfig indentation
fuse: fix leak of fuse_io_priv
virtiofs: Use completions while waiting for queue to be drained
virtiofs: Do not send forget request "struct list_head" element
virtiofs: Use a common function to send forget
virtiofs: Fix old-style declaration
fuse: verify nlink
fuse: verify write return
fuse: verify attributes
As part of the cleanup of some remaining y2038 issues, I came to
fs/compat_ioctl.c, which still has a couple of commands that need support
for time64_t.
In completely unrelated work, I spent time on cleaning up parts of this
file in the past, moving things out into drivers instead.
After Al Viro reviewed an earlier version of this series and did a lot
more of that cleanup, I decided to try to completely eliminate the rest
of it and move it all into drivers.
This series incorporates some of Al's work and many patches of my own,
but in the end stops short of actually removing the last part, which is
the scsi ioctl handlers. I have patches for those as well, but they need
more testing or possibly a rewrite.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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Merge tag 'compat-ioctl-5.5' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground
Pull removal of most of fs/compat_ioctl.c from Arnd Bergmann:
"As part of the cleanup of some remaining y2038 issues, I came to
fs/compat_ioctl.c, which still has a couple of commands that need
support for time64_t.
In completely unrelated work, I spent time on cleaning up parts of
this file in the past, moving things out into drivers instead.
After Al Viro reviewed an earlier version of this series and did a lot
more of that cleanup, I decided to try to completely eliminate the
rest of it and move it all into drivers.
This series incorporates some of Al's work and many patches of my own,
but in the end stops short of actually removing the last part, which
is the scsi ioctl handlers. I have patches for those as well, but they
need more testing or possibly a rewrite"
* tag 'compat-ioctl-5.5' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground: (42 commits)
scsi: sd: enable compat ioctls for sed-opal
pktcdvd: add compat_ioctl handler
compat_ioctl: move SG_GET_REQUEST_TABLE handling
compat_ioctl: ppp: move simple commands into ppp_generic.c
compat_ioctl: handle PPPIOCGIDLE for 64-bit time_t
compat_ioctl: move PPPIOCSCOMPRESS to ppp_generic
compat_ioctl: unify copy-in of ppp filters
tty: handle compat PPP ioctls
compat_ioctl: move SIOCOUTQ out of compat_ioctl.c
compat_ioctl: handle SIOCOUTQNSD
af_unix: add compat_ioctl support
compat_ioctl: reimplement SG_IO handling
compat_ioctl: move WDIOC handling into wdt drivers
fs: compat_ioctl: move FITRIM emulation into file systems
gfs2: add compat_ioctl support
compat_ioctl: remove unused convert_in_user macro
compat_ioctl: remove last RAID handling code
compat_ioctl: remove /dev/raw ioctl translation
compat_ioctl: remove PCI ioctl translation
compat_ioctl: remove joystick ioctl translation
...
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Merge tag 'notifications-pipe-prep-20191115' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull pipe rework from David Howells:
"This is my set of preparatory patches for building a general
notification queue on top of pipes. It makes a number of significant
changes:
- It removes the nr_exclusive argument from __wake_up_sync_key() as
this is always 1. This prepares for the next step:
- Adds wake_up_interruptible_sync_poll_locked() so that poll can be
woken up from a function that's holding the poll waitqueue
spinlock.
- Change the pipe buffer ring to be managed in terms of unbounded
head and tail indices rather than bounded index and length. This
means that reading the pipe only needs to modify one index, not
two.
- A selection of helper functions are provided to query the state of
the pipe buffer, plus a couple to apply updates to the pipe
indices.
- The pipe ring is allowed to have kernel-reserved slots. This allows
many notification messages to be spliced in by the kernel without
allowing userspace to pin too many pages if it writes to the same
pipe.
- Advance the head and tail indices inside the pipe waitqueue lock
and use wake_up_interruptible_sync_poll_locked() to poke poll
without having to take the lock twice.
- Rearrange pipe_write() to preallocate the buffer it is going to
write into and then drop the spinlock. This allows kernel
notifications to then be added the ring whilst it is filling the
buffer it allocated. The read side is stalled because the pipe
mutex is still held.
- Don't wake up readers on a pipe if there was already data in it
when we added more.
- Don't wake up writers on a pipe if the ring wasn't full before we
removed a buffer"
* tag 'notifications-pipe-prep-20191115' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
pipe: Remove sync on wake_ups
pipe: Increase the writer-wakeup threshold to reduce context-switch count
pipe: Check for ring full inside of the spinlock in pipe_write()
pipe: Remove redundant wakeup from pipe_write()
pipe: Rearrange sequence in pipe_write() to preallocate slot
pipe: Conditionalise wakeup in pipe_read()
pipe: Advance tail pointer inside of wait spinlock in pipe_read()
pipe: Allow pipes to have kernel-reserved slots
pipe: Use head and tail pointers for the ring, not cursor and length
Add wake_up_interruptible_sync_poll_locked()
Remove the nr_exclusive argument from __wake_up_sync_key()
pipe: Reduce #inclusion of pipe_fs_i.h
Adjust indentation from spaces to tab (+optional two spaces) as in
coding style with command like:
$ sed -e 's/^ /\t/' -i */Kconfig
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
exit_aio() is sometimes stuck in wait_for_completion() after aio is issued
with direct IO and the task receives a signal.
The reason is failure to call ->ki_complete() due to a leaked reference to
fuse_io_priv. This happens in fuse_async_req_send() if
fuse_simple_background() returns an error (e.g. -EINTR).
In this case the error value is propagated via io->err, so return success
to not confuse callers.
This issue is tracked as a virtio-fs issue:
https://gitlab.com/virtio-fs/qemu/issues/14
Reported-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Fixes: 45ac96ed7c ("fuse: convert direct_io to simple api")
Cc: <stable@vger.kernel.org> # v5.4
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
While we wait for queue to finish draining, use completions instead of
usleep_range(). This is better way of waiting for event.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
We are sending whole of virtio_fs_forget struct to the other end over
virtqueue. Other end does not need to see elements like "struct list".
That's internal detail of guest kernel. Fix it.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Currently we are duplicating logic to send forgets at two
places. Consolidate the code by calling one helper function.
This also uses virtqueue_add_outbuf() instead of
virtqueue_add_sgs(). Former is simpler to call.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Split pipe->ring_size into two numbers:
(1) pipe->ring_size - indicates the hard size of the pipe ring.
(2) pipe->max_usage - indicates the maximum number of pipe ring slots that
userspace orchestrated events can fill.
This allows for a pipe that is both writable by the general kernel
notification facility and by userspace, allowing plenty of ring space for
notifications to be added whilst preventing userspace from being able to
pin too much unswappable kernel space.
Signed-off-by: David Howells <dhowells@redhat.com>
There expect the 'static' keyword to come first in a declaration, and we
get warnings like this with "make W=1":
fs/fuse/virtio_fs.c:687:1: warning: 'static' is not at beginning of declaration [-Wold-style-declaration]
fs/fuse/virtio_fs.c:692:1: warning: 'static' is not at beginning of declaration [-Wold-style-declaration]
fs/fuse/virtio_fs.c:1029:1: warning: 'static' is not at beginning of declaration [-Wold-style-declaration]
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
When adding a new hard link, make sure that i_nlink doesn't overflow.
Fixes: ac45d61357 ("fuse: fix nlink after unlink")
Cc: <stable@vger.kernel.org> # v3.4
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Make sure filesystem is not returning a bogus number of bytes written.
Fixes: ea9b9907b8 ("fuse: implement perform_write")
Cc: <stable@vger.kernel.org> # v2.6.26
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
If a filesystem returns negative inode sizes, future reads on the file were
causing the cpu to spin on truncate_pagecache.
Create a helper to validate the attributes. This now does two things:
- check the file mode
- check if the file size fits in i_size without overflowing
Reported-by: Arijit Banerjee <arijit@rubrik.com>
Fixes: d8a5ba4545 ("[PATCH] FUSE - core")
Cc: <stable@vger.kernel.org> # v2.6.14
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Convert pipes to use head and tail pointers for the buffer ring rather than
pointer and length as the latter requires two atomic ops to update (or a
combined op) whereas the former only requires one.
(1) The head pointer is the point at which production occurs and points to
the slot in which the next buffer will be placed. This is equivalent
to pipe->curbuf + pipe->nrbufs.
The head pointer belongs to the write-side.
(2) The tail pointer is the point at which consumption occurs. It points
to the next slot to be consumed. This is equivalent to pipe->curbuf.
The tail pointer belongs to the read-side.
(3) head and tail are allowed to run to UINT_MAX and wrap naturally. They
are only masked off when the array is being accessed, e.g.:
pipe->bufs[head & mask]
This means that it is not necessary to have a dead slot in the ring as
head == tail isn't ambiguous.
(4) The ring is empty if "head == tail".
A helper, pipe_empty(), is provided for this.
(5) The occupancy of the ring is "head - tail".
A helper, pipe_occupancy(), is provided for this.
(6) The number of free slots in the ring is "pipe->ring_size - occupancy".
A helper, pipe_space_for_user() is provided to indicate how many slots
userspace may use.
(7) The ring is full if "head - tail >= pipe->ring_size".
A helper, pipe_full(), is provided for this.
Signed-off-by: David Howells <dhowells@redhat.com>
The .ioctl and .compat_ioctl file operations have the same prototype so
they can both point to the same function, which works great almost all
the time when all the commands are compatible.
One exception is the s390 architecture, where a compat pointer is only
31 bit wide, and converting it into a 64-bit pointer requires calling
compat_ptr(). Most drivers here will never run in s390, but since we now
have a generic helper for it, it's easy enough to use it consistently.
I double-checked all these drivers to ensure that all ioctl arguments
are used as pointers or are ignored, but are not interpreted as integer
values.
Acked-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: David Sterba <dsterba@suse.com>
Acked-by: Darren Hart (VMware) <dvhart@infradead.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Currently fuse_writepages_fill() calls get_fuse_inode() few times with
the same argument.
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Make sure cached writes are not reordered around open(..., O_TRUNC), with
the obvious wrong results.
Fixes: 4d99ff8f12 ("fuse: Turn writeback cache on")
Cc: <stable@vger.kernel.org> # v3.15+
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
If writeback cache is enabled, then writes might get reordered with
chmod/chown/utimes. The problem with this is that performing the write in
the fuse daemon might itself change some of these attributes. In such case
the following sequence of operations will result in file ending up with the
wrong mode, for example:
int fd = open ("suid", O_WRONLY|O_CREAT|O_EXCL);
write (fd, "1", 1);
fchown (fd, 0, 0);
fchmod (fd, 04755);
close (fd);
This patch fixes this by flushing pending writes before performing
chown/chmod/utimes.
Reported-by: Giuseppe Scrivano <gscrivan@redhat.com>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Fixes: 4d99ff8f12 ("fuse: Turn writeback cache on")
Cc: <stable@vger.kernel.org> # v3.15+
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes gcc '-Wunused-but-set-variable' warning:
fs/fuse/virtio_fs.c: In function virtio_fs_wake_pending_and_unlock:
fs/fuse/virtio_fs.c:983:20: warning: variable fc set but not used [-Wunused-but-set-variable]
It is not used since commit 7ee1e2e631 ("virtiofs: No need to check
fpq->connected state")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
If regular request queue gets full, currently we sleep for a bit and
retrying submission in submitter's context. This assumes submitter is not
holding any spin lock. But this assumption is not true for background
requests. For background requests, we are called with fc->bg_lock held.
This can lead to deadlock where one thread is trying submission with
fc->bg_lock held while request completion thread has called
fuse_request_end() which tries to acquire fc->bg_lock and gets blocked. As
request completion thread gets blocked, it does not make further progress
and that means queue does not get empty and submitter can't submit more
requests.
To solve this issue, retry submission with the help of a worker, instead of
retrying in submitter's context. We already do this for hiprio/forget
requests.
Reported-by: Chirantan Ekbote <chirantan@chromium.org>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
If virtqueue is full, we put forget requests on a list and these forgets
are dispatched later using a worker. As of now we don't count these forgets
in fsvq->in_flight variable. This means when queue is being drained, we
have to have special logic to first drain these pending requests and then
wait for fsvq->in_flight to go to zero.
By counting pending forgets in fsvq->in_flight, we can get rid of special
logic and just wait for in_flight to go to zero. Worker thread will kick
and drain all the forgets anyway, leading in_flight to zero.
I also need similar logic for normal request queue in next patch where I am
about to defer request submission in the worker context if queue is full.
This simplifies the code a bit.
Also add two helper functions to inc/dec in_flight. Decrement in_flight
helper will later used to call completion when in_flight reaches zero.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
FR_SENT flag should be set when request has been sent successfully sent
over virtqueue. This is used by interrupt logic to figure out if interrupt
request should be sent or not.
Also add it to fqp->processing list after sending it successfully.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
In virtiofs we keep per queue connected state in virtio_fs_vq->connected
and use that to end request if queue is not connected. And virtiofs does
not even touch fpq->connected state.
We probably need to merge these two at some point of time. For now,
simplify the code a bit and do not worry about checking state of
fpq->connected.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Submission context can hold some locks which end request code tries to hold
again and deadlock can occur. For example, fc->bg_lock. If a background
request is being submitted, it might hold fc->bg_lock and if we could not
submit request (because device went away) and tried to end request, then
deadlock happens. During testing, I also got a warning from deadlock
detection code.
So put requests on a list and end requests from a worker thread.
I got following warning from deadlock detector.
[ 603.137138] WARNING: possible recursive locking detected
[ 603.137142] --------------------------------------------
[ 603.137144] blogbench/2036 is trying to acquire lock:
[ 603.137149] 00000000f0f51107 (&(&fc->bg_lock)->rlock){+.+.}, at: fuse_request_end+0xdf/0x1c0 [fuse]
[ 603.140701]
[ 603.140701] but task is already holding lock:
[ 603.140703] 00000000f0f51107 (&(&fc->bg_lock)->rlock){+.+.}, at: fuse_simple_background+0x92/0x1d0 [fuse]
[ 603.140713]
[ 603.140713] other info that might help us debug this:
[ 603.140714] Possible unsafe locking scenario:
[ 603.140714]
[ 603.140715] CPU0
[ 603.140716] ----
[ 603.140716] lock(&(&fc->bg_lock)->rlock);
[ 603.140718] lock(&(&fc->bg_lock)->rlock);
[ 603.140719]
[ 603.140719] *** DEADLOCK ***
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
If the FUSE_READDIRPLUS_AUTO feature is enabled, then lookups on a
directory before/during readdir are used as an indication that READDIRPLUS
should be used instead of READDIR. However if the lookup turns out to be
negative, then selecting READDIRPLUS makes no sense.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Move the check for async request after check for the request being already
finished and done with.
Reported-by: syzbot+ae0bb7aae3de6b4594e2@syzkaller.appspotmail.com
Fixes: d49937749f ("fuse: stop copying args to fuse_req")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Virtio-fs does not accept any mount options, so it's confusing and wrong to
show any in /proc/mounts.
Reported-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
We have been calling it virtio_fs and even file name is virtio_fs.c. Module
name is virtio_fs.ko but when registering file system user is supposed to
specify filesystem type as "virtiofs".
Masayoshi Mizuma reported that he specified filesytem type as "virtio_fs"
and got this warning on console.
------------[ cut here ]------------
request_module fs-virtio_fs succeeded, but still no fs?
WARNING: CPU: 1 PID: 1234 at fs/filesystems.c:274 get_fs_type+0x12c/0x138
Modules linked in: ... virtio_fs fuse virtio_net net_failover ...
CPU: 1 PID: 1234 Comm: mount Not tainted 5.4.0-rc1 #1
So looks like kernel could find the module virtio_fs.ko but could not find
filesystem type after that.
It probably is better to rename module name to virtiofs.ko so that above
warning goes away in case user ends up specifying wrong fs name.
Reported-by: Masayoshi Mizuma <msys.mizuma@gmail.com>
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Tested-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Merge tag 'virtio-fs-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
Pull fuse virtio-fs support from Miklos Szeredi:
"Virtio-fs allows exporting directory trees on the host and mounting
them in guest(s).
This isn't actually a new filesystem, but a glue layer between the
fuse filesystem and a virtio based back-end.
It's similar in functionality to the existing virtio-9p solution, but
significantly faster in benchmarks and has better POSIX compliance.
Further permformance improvements can be achieved by sharing the page
cache between host and guest, allowing for faster I/O and reduced
memory use.
Kata Containers have been including the out-of-tree virtio-fs (with
the shared page cache patches as well) since version 1.7 as an
experimental feature. They have been active in development and plan to
switch from virtio-9p to virtio-fs as their default solution. There
has been interest from other sources as well.
The userspace infrastructure is slated to be merged into qemu once the
kernel part hits mainline.
This was developed by Vivek Goyal, Dave Gilbert and Stefan Hajnoczi"
* tag 'virtio-fs-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
virtio-fs: add virtiofs filesystem
virtio-fs: add Documentation/filesystems/virtiofs.rst
fuse: reserve values for mapping protocol
Fix sparse warning:
fs/fuse/dev.c:468:6: warning: symbol 'fuse_args_to_req' was not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Fixes: 68583165f9 ("fuse: add pages to fuse_args")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This function has been made static, which now causes a compile-time
warning:
WARNING: "fuse_put_request" [vmlinux] is a static EXPORT_SYMBOL_GPL
Remove the unneeded export.
Fixes: 66abc3599c ("fuse: unexport request ops")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
account per-file, dentry, and inode data
blockdev/superblock and temporary per-request data was left alone, as
this usually isn't accounted
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Implements the optimization noted in commit f75fdf22b0 ("fuse: don't
use ->d_time"), as the additional memory can be significant. (In
particular, on SLAB configurations this 8-byte alloc becomes 32 bytes).
Per-dentry, this can consume significant memory.
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
unlock_page() was missing in case of an already in-flight write against the
same page.
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Fixes: ff17be0864 ("fuse: writepage: skip already in flight")
Cc: <stable@vger.kernel.org> # v3.13
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Add a basic file system module for virtio-fs. This does not yet contain
shared data support between host and guest or metadata coherency speedups.
However it is already significantly faster than virtio-9p.
Design Overview
===============
With the goal of designing something with better performance and local file
system semantics, a bunch of ideas were proposed.
- Use fuse protocol (instead of 9p) for communication between guest and
host. Guest kernel will be fuse client and a fuse server will run on
host to serve the requests.
- For data access inside guest, mmap portion of file in QEMU address space
and guest accesses this memory using dax. That way guest page cache is
bypassed and there is only one copy of data (on host). This will also
enable mmap(MAP_SHARED) between guests.
- For metadata coherency, there is a shared memory region which contains
version number associated with metadata and any guest changing metadata
updates version number and other guests refresh metadata on next access.
This is yet to be implemented.
How virtio-fs differs from existing approaches
==============================================
The unique idea behind virtio-fs is to take advantage of the co-location of
the virtual machine and hypervisor to avoid communication (vmexits).
DAX allows file contents to be accessed without communication with the
hypervisor. The shared memory region for metadata avoids communication in
the common case where metadata is unchanged.
By replacing expensive communication with cheaper shared memory accesses,
we expect to achieve better performance than approaches based on network
file system protocols. In addition, this also makes it easier to achieve
local file system semantics (coherency).
These techniques are not applicable to network file system protocols since
the communications channel is bypassed by taking advantage of shared memory
on a local machine. This is why we decided to build virtio-fs rather than
focus on 9P or NFS.
Caching Modes
=============
Like virtio-9p, different caching modes are supported which determine the
coherency level as well. The “cache=FOO” and “writeback” options control
the level of coherence between the guest and host filesystems.
- cache=none
metadata, data and pathname lookup are not cached in guest. They are
always fetched from host and any changes are immediately pushed to host.
- cache=always
metadata, data and pathname lookup are cached in guest and never expire.
- cache=auto
metadata and pathname lookup cache expires after a configured amount of
time (default is 1 second). Data is cached while the file is open
(close to open consistency).
- writeback/no_writeback
These options control the writeback strategy. If writeback is disabled,
then normal writes will immediately be synchronized with the host fs.
If writeback is enabled, then writes may be cached in the guest until
the file is closed or an fsync(2) performed. This option has no effect
on mmap-ed writes or writes going through the DAX mechanism.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
virtio-fs does not support aborting requests which are being
processed. That is requests which have been sent to fuse daemon on host.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Miklos Szeredi