Interrupt is only queued after the request has been sent to userspace.
This is either done in request_wait_answer() or fuse_dev_do_read()
depending on which state the request is in at the time of the interrupt.
If it's not yet sent, then queuing the interrupt is postponed until the
request is read. Otherwise (the request has already been read and is
waiting for an answer) the interrupt is queued immedidately.
We want to call queue_interrupt() without fc->lock protection, in which
case there can be a race between the two functions:
- neither of them queue the interrupt (thinking the other one has already
done it).
- both of them queue the interrupt
The first one is prevented by adding memory barriers, the second is
prevented by checking (under fiq->waitq.lock) if the interrupt has already
been queued.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Use fiq->waitq.lock for protecting members of struct fuse_iqueue and
FR_PENDING request flag, previously protected by fc->lock.
Following patches will remove fc->lock protection from these members.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
This will allow checking ->connected just with the input queue lock.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
The input queue contains normal requests (fc->pending), forgets
(fc->forget_*) and interrupts (fc->interrupts). There's also fc->waitq and
fc->fasync for waking up the readers of the fuse device when a request is
available.
The fc->reqctr is also moved to the input queue (assigned to the request
when the request is added to the input queue.
This patch just rearranges the fields, no functional change.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
Use flags for representing the state in fuse_req. This is needed since
req->list will be protected by different locks in different states, hence
we'll want the state itself to be split into distinct bits, each protected
with the relevant lock in that state.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
FUSE_REQ_INIT is actually the same state as FUSE_REQ_PENDING and
FUSE_REQ_READING and FUSE_REQ_WRITING can be merged into a common
FUSE_REQ_IO state.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
Only hold fc->lock over sections of request_wait_answer() that actually
need it. If wait_event_interruptible() returns zero, it means that the
request finished. Need to add memory barriers, though, to make sure that
all relevant data in the request is synchronized.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Since it's a 64bit counter, it's never gonna wrap around. Remove code
dealing with that possibility.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
Splice fc->pending and fc->processing lists into a common kill list while
holding fc->lock.
By the time we release fc->lock, pending and processing lists are empty and
the io list contains only locked requests.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
Finer grained locking will mean there's no single lock to protect
modification of bitfileds in fuse_req.
So move to using bitops. Can use the non-atomic variants for those which
happen while the request definitely has only one reference.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
- don't end the request while req->locked is true
- make unlock_request() return an error if the connection was aborted
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
fuse_abort_conn() does all the work done by fuse_dev_release() and more.
"More" consists of:
end_io_requests(fc);
wake_up_all(&fc->waitq);
kill_fasync(&fc->fasync, SIGIO, POLL_IN);
All of which should be no-op (WARN_ON's added).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
And the same with fuse_request_send_nowait_locked().
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
fc->conn_error is set once in FUSE_INIT reply and never cleared. Check it
in request allocation, there's no sense in doing all the preparation if
sending will surely fail.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
Move accounting of fc->num_waiting to the point where the request actually
starts waiting. This is earlier than the current queue_request() for
background requests, since they might be waiting on the fc->bg_queue before
being queued on fc->pending.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
Reset req->waiting in fuse_put_request(). This is needed for correct
accounting in fc->num_waiting for reserved requests.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
request_end() expects fc->num_background and fc->active_background to have
been incremented, which is not the case in fuse_request_send_nowait()
failure path. So instead just call the ->end() callback (which is actually
set by all callers).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
struct kiocb now is a generic I/O container, so move it to fs.h.
Also do a #include diet for aio.h while we're at it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The misc subsystem (which is used for /dev/fuse) initializes private_data to
point to the misc device when a driver has registered a custom open file
operation, and initializes it to NULL when a custom open file operation has
*not* been provided.
This subtle quirk is confusing, to the point where kernel code registers
*empty* file open operations to have private_data point to the misc device
structure. And it leads to bugs, where the addition or removal of a custom open
file operation surprisingly changes the initial contents of a file's
private_data structure.
So to simplify things in the misc subsystem, a patch [1] has been proposed to
*always* set the private_data to point to the misc device, instead of only
doing this when a custom open file operation has been registered.
But before this patch can be applied we need to modify drivers that make the
assumption that a misc device file's private_data is initialized to NULL
because they didn't register a custom open file operation, so they don't rely
on this assumption anymore. FUSE uses private_data to store the fuse_conn and
errors out if this is not initialized to NULL at mount time.
Hence, we now set a file's private_data to NULL explicitly, to be independent
of whatever value the misc subsystem initializes it to by default.
[1] https://lkml.org/lkml/2014/12/4/939
Reported-by: Giedrius Statkevicius <giedriuswork@gmail.com>
Reported-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Tom Van Braeckel <tomvanbraeckel@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Regular pipe buffers' ->steal method (generic_pipe_buf_steal()) doesn't set
PG_uptodate.
Don't warn on this condition, just set the uptodate flag.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: stable@vger.kernel.org
fuse_try_move_page() is not prepared for replacing pages that have already
been read.
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: stable@vger.kernel.org
Theoretically we need to order setting of various fields in fc with
fc->initialized.
No known bug reports related to this yet.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Analysis from Marc:
"Commit 7078187a79 ("fuse: introduce fuse_simple_request() helper")
from the above pull request triggers some EIO errors for me in some tests
that rely on fuse
Looking at the code changes and a bit of debugging info I think there's a
general problem here that fuse_get_req checks and possibly waits for
fc->initialized, and this was always called first. But this commit
changes the ordering and in many places fc->minor is now possibly used
before fuse_get_req, and we can't be sure that fc has been initialized.
In my case fuse_lookup_init sets req->out.args[0].size to the wrong size
because fc->minor at that point is still 0, leading to the EIO error."
Fix by moving the compat adjustments into fuse_simple_request() to after
fuse_get_req().
This is also more readable than the original, since now compatibility is
handled in a single function instead of cluttering each operation.
Reported-by: Marc Dionne <marc.c.dionne@gmail.com>
Tested-by: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Fixes: 7078187a79 ("fuse: introduce fuse_simple_request() helper")
The following pattern is repeated many times:
req = fuse_get_req_nopages(fc);
/* Initialize req->(in|out).args */
fuse_request_send(fc, req);
err = req->out.h.error;
fuse_put_request(req);
Create a new replacement helper:
/* Initialize args */
err = fuse_simple_request(fc, &args);
In addition to reducing the code size, this will ease moving from the
complex arg-based to a simpler page-based I/O on the fuse device.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Pull fuse fixes from Miklos Szeredi:
"This contains miscellaneous fixes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: replace count*size kzalloc by kcalloc
fuse: release temporary page if fuse_writepage_locked() failed
fuse: restructure ->rename2()
fuse: avoid scheduling while atomic
fuse: handle large user and group ID
fuse: inode: drop cast
fuse: ignore entry-timeout on LOOKUP_REVAL
fuse: timeout comparison fix
As reported by Richard Sharpe, an attempt to use fuse_notify_inval_entry()
triggers complains about scheduling while atomic:
BUG: scheduling while atomic: fuse.hf/13976/0x10000001
This happens because fuse_notify_inval_entry() attempts to allocate memory
with GFP_KERNEL, holding "struct fuse_copy_state" mapped by kmap_atomic().
Introduced by commit 58bda1da4b "fuse/dev: use atomic maps"
Fix by moving the map/unmap to just cover the actual memcpy operation.
Original patch from Maxim Patlasov <mpatlasov@parallels.com>
Reported-by: Richard Sharpe <realrichardsharpe@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: <stable@vger.kernel.org> # v3.15+
cold is a bool, make it one. Make the likely case the "if" part of the
block instead of the else as according to the optimisation manual this is
preferred.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As noticed by Coverity the "num != 0" condition never triggers. Instead it
should check for a complete page.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Having this struct in module memory could Oops when if the module is
unloaded while the buffer still persists in a pipe.
Since sock_pipe_buf_ops is essentially the same as fuse_dev_pipe_buf_steal
merge them into nosteal_pipe_buf_ops (this is the same as
default_pipe_buf_ops except stealing the page from the buffer is not
allowed).
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: stable@vger.kernel.org
Merge more incoming from Andrew Morton:
- Various fixes which were stalled or which I picked up recently
- A large rotorooting of the AIO code. Allegedly to improve
performance but I don't really have good performance numbers (I might
have lost the email) and I can't raise Kent today. I held this out
of 3.9 and we could give it another cycle if it's all too late/scary.
I ended up taking only the first two thirds of the AIO rotorooting. I
left the percpu parts and the batch completion for later. - Linus
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (33 commits)
aio: don't include aio.h in sched.h
aio: kill ki_retry
aio: kill ki_key
aio: give shared kioctx fields their own cachelines
aio: kill struct aio_ring_info
aio: kill batch allocation
aio: change reqs_active to include unreaped completions
aio: use cancellation list lazily
aio: use flush_dcache_page()
aio: make aio_read_evt() more efficient, convert to hrtimers
wait: add wait_event_hrtimeout()
aio: refcounting cleanup
aio: make aio_put_req() lockless
aio: do fget() after aio_get_req()
aio: dprintk() -> pr_debug()
aio: move private stuff out of aio.h
aio: add kiocb_cancel()
aio: kill return value of aio_complete()
char: add aio_{read,write} to /dev/{null,zero}
aio: remove retry-based AIO
...
Pull fuse updates from Miklos Szeredi:
"This contains two patchsets from Maxim Patlasov.
The first reworks the request throttling so that only async requests
are throttled. Wakeup of waiting async requests is also optimized.
The second series adds support for async processing of direct IO which
optimizes direct IO and enables the use of the AIO userspace
interface."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: add flag to turn on async direct IO
fuse: truncate file if async dio failed
fuse: optimize short direct reads
fuse: enable asynchronous processing direct IO
fuse: make fuse_direct_io() aware about AIO
fuse: add support of async IO
fuse: move fuse_release_user_pages() up
fuse: optimize wake_up
fuse: implement exclusive wakeup for blocked_waitq
fuse: skip blocking on allocations of synchronous requests
fuse: add flag fc->initialized
fuse: make request allocations for background processing explicit
The patch implements passing "struct fuse_io_priv *io" down the stack up to
fuse_send_read/write where it is used to submit request asynchronously.
io->async==0 designates synchronous processing.
Non-trivial part of the patch is changes in fuse_direct_io(): resources
like fuse requests and user pages cannot be released immediately in async
case.
Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
The patch solves thundering herd problem. So far as previous patches ensured
that only allocations for background may block, it's safe to wake up one
waiter. Whoever it is, it will wake up another one in request_end() afterwards.
Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
A task may have at most one synchronous request allocated. So these
requests need not be otherwise limited.
The patch re-works fuse_get_req() to follow this idea.
Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Existing flag fc->blocked is used to suspend request allocation both in case
of many background request submitted and period of time before init_reply
arrives from userspace. Next patch will skip blocking allocations of
synchronous request (disregarding fc->blocked). This is mostly OK, but
we still need to suspend allocations if init_reply is not arrived yet. The
patch introduces flag fc->initialized which will serve this purpose.
Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
There are two types of processing requests in FUSE: synchronous (via
fuse_request_send()) and asynchronous (via adding to fc->bg_queue).
Fortunately, the type of processing is always known in advance, at the time
of request allocation. This preparatory patch utilizes this fact making
fuse_get_req() aware about the type. Next patches will use it.
Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
it's used only as a flag to distinguish normal pipes/FIFOs from the
internal per-task one used by file-to-file splice. And pipe->files
would work just as well for that purpose...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
