Commit Graph

166 Commits

Author SHA1 Message Date
David Xu
5ff2bb52cc I am comparing current pipe code with the one in 8.3-STABLE r236165,
I found 8.3 is a history BSD version using socket to implement FIFO
pipe, it uses per-file seqcount to compare with writer generation
stored in per-pipe object. The concept is after all writers are gone,
the pipe enters next generation, all old readers have not closed the
pipe should get the indication that the pipe is disconnected, result
is they should get EPIPE, SIGPIPE or get POLLHUP in poll().
But newcomer should not know that previous writters were gone, it
should treat it as a fresh session.
I am trying to bring back FIFO pipe to history behavior. It is still
unclear that if single EOF flag can represent SBS_CANTSENDMORE and
SBS_CANTRCVMORE which socket-based version is using, but I have run
the poll regression test in tool directory, output is same as the one
on 8.3-STABLE now.
I think the output "not ok 18 FIFO state 6b: poll result 0 expected 1.
expected POLLHUP; got 0" might be bogus, because newcomer should not
know that old writers were gone. I got the same behavior on Linux.
Our implementation always return POLLIN for disconnected pipe even it
should return POLLHUP, but I think it is not wise to remove POLLIN for
compatible reason, this is our history behavior.

Regression test: /usr/src/tools/regression/poll
2012-07-31 05:48:35 +00:00
David Xu
12a480fa41 When a thread is blocked in direct write state, it only sets PIPE_DIRECTW
flag but not PIPE_WANTW, but FIFO pipe code does not understand this internal
state, when a FIFO peer reader closes the pipe, it wants to notify the writer,
it checks PIPE_WANTW, if not set, it skips calling wakeup(), so blocked writer
never noticed the case, but in general, the writer should return from the
syscall with EPIPE error code and may get SIGPIPE signal. Setting the
PIPE_WANTW fixed problem, or you can turn off direct write, it should fix the
problem too. This bug is found by PR/170203.

Another bug in FIFO pipe code is when peer closes the pipe, another end which
is being blocked in select() or poll() is not notified, it missed to call
pipeselwakeup().

Third problem is found in poll regression test, the existing code can not
pass 6b,6c,6d tests, but FreeBSD-4 works. This commit does not fix the
problem, I still need to study more to find the cause.

PR: 170203
Tested by: Garrett Copper < yanegomi at gmail dot com >
2012-07-31 02:00:37 +00:00
Konstantin Belousov
0e738b4c0f Update comment.
Submitted by:	gianni
2012-03-11 15:58:27 +00:00
Konstantin Belousov
b80dcb55aa Remove fifo.h. The only used function declaration from the header is
migrated to sys/vnode.h.

Submitted by:	gianni
2012-03-11 12:19:58 +00:00
Konstantin Belousov
f950879e16 The pipe_poll() performs lockless access to the vnode to test
fifo_iseof() condition, allowing the v_fifoinfo to be reset and freed
by fifo_cleanup().

Precalculate EOF at the places were fo_wgen is changed, and cache the
state in a new pipe state flag PIPE_SAMEWGEN.

Reported and tested by:	bf
Submitted by:	gianni
MFC after:	1 week (a backport)
2012-03-07 07:31:50 +00:00
Kip Macy
11ac7ec076 merge pipe and fifo implementations
Also reviewed by: jhb, jilles (initial revision)
Tested by: pho, jilles

Submitted by:	gianni
Reviewed by:	bde
2012-02-23 18:37:30 +00:00
Konstantin Belousov
d8e8af3166 Initialize fifoinfo fi_wgen field on open. The only important is the
difference between fi_wgen and f_seqcount, so the change is purely
cosmetic, but it makes the code easier to understand.

Submitted by:	gianni
MFC after:	2 weeks
2011-12-04 19:25:49 +00:00
Konstantin Belousov
9c00bb9190 Add the fo_chown and fo_chmod methods to struct fileops and use them
to implement fchown(2) and fchmod(2) support for several file types
that previously lacked it. Add MAC entries for chown/chmod done on
posix shared memory and (old) in-kernel posix semaphores.

Based on the submission by:	glebius
Reviewed by:	rwatson
Approved by:	re (bz)
2011-08-16 20:07:47 +00:00
Attilio Rao
9c76640868 - Improve comments about locking of the "struct fifoinfo" which is a bit
unclear.
- Fix a memory leak [0]

[0] Diagnosed by:	Dorr H. Clark <dclark at engr dot scu dot edu>
MFC:	1 week
2009-11-06 22:29:46 +00:00
Edward Tomasz Napierala
2c29cfa083 Provide default implementation for VOP_ACCESS(9), so that filesystems which
want to provide VOP_ACCESSX(9) don't have to implement both.  Note that
this commit makes implementation of either of these two mandatory.

Reviewed by:	kib
2009-10-01 17:22:03 +00:00
Robert Watson
e76d823b81 Use C99 initialization for struct filterops.
Obtained from:	Mac OS X
Sponsored by:	Apple Inc.
MFC after:	3 weeks
2009-09-12 20:03:45 +00:00
Jilles Tjoelker
74d1c4927a Fix poll() on half-closed sockets, while retaining POLLHUP for fifos.
This reverts part of r196460, so that sockets only return POLLHUP if both
directions are closed/error. Fifos get POLLHUP by closing the unused
direction immediately after creating the sockets.

The tools/regression/poll/*poll.c tests now pass except for two other things:
- if POLLHUP is returned, POLLIN is always returned as well instead of only
  when there is data left in the buffer to be read
- fifo old/new reader distinction does not work the way POSIX specs it

Reviewed by:	kib, bde
2009-08-25 21:44:14 +00:00
Konstantin Belousov
7f5dff5064 Fix poll(2) and select(2) for named pipes to return "ready for read"
when all writers, observed by reader, exited. Use writer generation
counter for fifo, and store the snapshot of the fifo generation in the
f_seqcount field of struct file, that is otherwise unused for fifos.
Set FreeBSD-undocumented POLLINIGNEOF flag only when file f_seqcount is
equal to fifo' fi_wgen, and revert r89376.

Fix POLLINIGNEOF for sockets and pipes, and return POLLHUP for them.
Note that the patch does not fix not returning POLLHUP for fifos.

PR:	kern/94772
Submitted by:	bde (original version)
Reviewed by:	rwatson, jilles
Approved by:	re (kensmith)
MFC after:	6 weeks (might be)
2009-07-07 09:43:44 +00:00
Konstantin Belousov
e4d9bdc105 s/a_fdidx/a_fp/ for VOP_OPEN comments that inline struct vop_open_args
definition.

Discussed with:	bde
MFC after:	2 weeks
2009-06-10 14:09:05 +00:00
Konstantin Belousov
c4702e66f4 Remove unused VOP_IOCTL and VOP_KQFILTER implementations for fifofs.
MFC after:	2 weeks
2009-06-10 14:02:22 +00:00
Robert Watson
885868cd8f Remove VOP_LEASE and supporting functions. This hasn't been used since
the removal of NQNFS, but was left in in case it was required for NFSv4.
Since our new NFSv4 client and server can't use it for their
requirements, GC the old mechanism, as well as other unused lease-
related code and interfaces.

Due to its impact on kernel programming and binary interfaces, this
change should not be MFC'd.

Proposed by:    jeff
Reviewed by:    jeff
Discussed with: rmacklem, zach loafman @ isilon
2009-04-10 10:52:19 +00:00
John Baldwin
8941aad19b Tweak the output of VOP_PRINT/vn_printf() some.
- Align the fifo output in fifo_print() with other vn_printf() output.
- Remove the leading space from lockmgr_printinfo() so its output lines up
  in vn_printf().
- lockmgr_printinfo() now ends with a newline, so remove an extra newline
  from vn_printf().
2009-02-06 20:06:48 +00:00
John Baldwin
be09858abd Assert an exclusive vnode lock for fifo_cleanup() and fifo_close() since
they change v_fifoinfo.

Discussed with:	ups (a while ago)
2009-01-28 18:10:57 +00:00
Konstantin Belousov
e442a285a6 The kernel may do unbalanced calls to fifo_close() for fifo vnode,
without corresponding number of fifo_open(). This causes assertion
failure in fifo_close() due to vp->v_fifoinfo being NULL for kernel
with INVARIANTS, or NULL pointer dereference otherwise. In fact, we may
ignore excess calls to fifo_close() without bad consequences.

Turn KASSERT() into the return, and print warning for now.

Tested by:	pho
Reviewed by:	rwatson
MFC after:	2 weeks
2009-01-26 14:21:00 +00:00
Dag-Erling Smørgrav
1ede983cc9 Retire the MALLOC and FREE macros. They are an abomination unto style(9).
MFC after:	3 months
2008-10-23 15:53:51 +00:00
Jeff Roberson
6617724c5f Remove kernel support for M:N threading.
While the KSE project was quite successful in bringing threading to
FreeBSD, the M:N approach taken by the kse library was never developed
to its full potential.  Backwards compatibility will be provided via
libmap.conf for dynamically linked binaries and static binaries will
be broken.
2008-03-12 10:12:01 +00:00
Robert Watson
c55376e791 Remove Giant acquisition around soreceive() and sosend() in fifofs. The
bug that caused us to reintroduce it is believed to be fixed, and Kris
says he no longer sees problems with fifofs in highly parallel builds.
If this works out, we'll MFC it for 7.1.

MFC after:	3 months
Pointed out by:	kris
2008-01-26 12:34:23 +00:00
Attilio Rao
22db15c06f VOP_LOCK1() (and so VOP_LOCK()) and VOP_UNLOCK() are only used in
conjuction with 'thread' argument passing which is always curthread.
Remove the unuseful extra-argument and pass explicitly curthread to lower
layer functions, when necessary.

KPI results broken by this change, which should affect several ports, so
version bumping and manpage update will be further committed.

Tested by: kris, pho, Diego Sardina <siarodx at gmail dot com>
2008-01-13 14:44:15 +00:00
Attilio Rao
cb05b60a89 vn_lock() is currently only used with the 'curthread' passed as argument.
Remove this argument and pass curthread directly to underlying
VOP_LOCK1() VFS method. This modify makes the code cleaner and in
particular remove an annoying dependence helping next lockmgr() cleanup.
KPI results, obviously, changed.

Manpage and FreeBSD_version will be updated through further commits.

As a side note, would be valuable to say that next commits will address
a similar cleanup about VFS methods, in particular vop_lock1 and
vop_unlock.

Tested by:	Diego Sardina <siarodx at gmail dot com>,
		Andrea Di Pasquale <whyx dot it at gmail dot com>
2008-01-10 01:10:58 +00:00
John Baldwin
e46502943a Make ftruncate a 'struct file' operation rather than a vnode operation.
This makes it possible to support ftruncate() on non-vnode file types in
the future.
- 'struct fileops' grows a 'fo_truncate' method to handle an ftruncate() on
  a given file descriptor.
- ftruncate() moves to kern/sys_generic.c and now just fetches a file
  object and invokes fo_truncate().
- The vnode-specific portions of ftruncate() move to vn_truncate() in
  vfs_vnops.c which implements fo_truncate() for vnode file types.
- Non-vnode file types return EINVAL in their fo_truncate() method.

Submitted by:	rwatson
2008-01-07 20:05:19 +00:00
Jeff Roberson
397c19d175 Remove explicit locking of struct file.
- Introduce a finit() which is used to initailize the fields of struct file
   in such a way that the ops vector is only valid after the data, type,
   and flags are valid.
 - Protect f_flag and f_count with atomic operations.
 - Remove the global list of all files and associated accounting.
 - Rewrite the unp garbage collection such that it no longer requires
   the global list of all files and instead uses a list of all unp sockets.
 - Mark sockets in the accept queue so we don't incorrectly gc them.

Tested by:	kris, pho
2007-12-30 01:42:15 +00:00
Pawel Jakub Dawidek
57fd3d5572 When we do open, we should lock the vnode exclusively. This fixes few races:
- fifo race, where two threads assign v_fifoinfo,
- v_writecount modifications,
- v_object modifications,
- and probably more...

Discussed with:	kib, ups
Approved by:	re (rwatson)
2007-07-26 16:58:09 +00:00
Konstantin Belousov
9e223287c0 Revert UF_OPENING workaround for CURRENT.
Change the VOP_OPEN(), vn_open() vnode operation and d_fdopen() cdev operation
argument from being file descriptor index into the pointer to struct file.

Proposed and reviewed by:	jhb
Reviewed by:	daichi (unionfs)
Approved by:	re (kensmith)
2007-05-31 11:51:53 +00:00
Robert Watson
5e3f7694b1 Replace custom file descriptor array sleep lock constructed using a mutex
and flags with an sxlock.  This leads to a significant and measurable
performance improvement as a result of access to shared locking for
frequent lookup operations, reduced general overhead, and reduced overhead
in the event of contention.  All of these are imported for threaded
applications where simultaneous access to a shared file descriptor array
occurs frequently.  Kris has reported 2x-4x transaction rate improvements
on 8-core MySQL benchmarks; smaller improvements can be expected for many
workloads as a result of reduced overhead.

- Generally eliminate the distinction between "fast" and regular
  acquisisition of the filedesc lock; the plan is that they will now all
  be fast.  Change all locking instances to either shared or exclusive
  locks.

- Correct a bug (pointed out by kib) in fdfree() where previously msleep()
  was called without the mutex held; sx_sleep() is now always called with
  the sxlock held exclusively.

- Universally hold the struct file lock over changes to struct file,
  rather than the filedesc lock or no lock.  Always update the f_ops
  field last. A further memory barrier is required here in the future
  (discussed with jhb).

- Improve locking and reference management in linux_at(), which fails to
  properly acquire vnode references before using vnode pointers.  Annotate
  improper use of vn_fullpath(), which will be replaced at a future date.

In fcntl(), we conservatively acquire an exclusive lock, even though in
some cases a shared lock may be sufficient, which should be revisited.
The dropping of the filedesc lock in fdgrowtable() is no longer required
as the sxlock can be held over the sleep operation; we should consider
removing that (pointed out by attilio).

Tested by:	kris
Discussed with:	jhb, kris, attilio, jeff
2007-04-04 09:11:34 +00:00
Mike Pritchard
45cdcb7aab Change fifo_printinfo to check if the vnode v_fifoinfo pointer
is NULL and print a message to that effect to prevent a panic.
2007-03-02 00:10:11 +00:00
Robert Watson
eca7e73743 Add a_fdidx to comment prototype for fifo_open().
MFC after:	3 days
Submitted by:	Kostik Belousov <kostikbel at gmail dot com>
2006-03-15 10:15:35 +00:00
Robert Watson
945a519a23 If fifo_open() is called with a negative file descriptor, return EINVAL
rather than panicking later.  This can occur if the kernel calls
vn_open() on a fifo, as there will be no associated file descriptor,
and therefore the file descriptor operations cannot be modified to
point to the fifo operation set.

MFC after:	3 days
Reported by:	Martin <nakal at nurfuerspam dot de>
PR:		94278
2006-03-14 19:29:45 +00:00
Robert Watson
2affdbee3e Second attempt at a work-around for fifo-related socket panics during
make -j with high levels of parallelism: acquire Giant in fifo I/O
routines.

Discussed with:	ups
MFC after:	3 days
2005-10-01 20:15:41 +00:00
Robert Watson
a0e81bce69 Back out fifo_vnops.c:1.127, which introduced an sx lock around I/O on
a fifo.  While this did indeed close the race, confirming suspicions
about the nature of the problem, it causes difficulties with blocking
I/O on fifos.

Discussed with:		ups
Also spotted by:	Peter Holm <peter at holm dot cc>
2005-09-27 16:45:22 +00:00
Robert Watson
454c3d13be Assert v_fifoinfo is non-NULL in fifo_close() in order to catch
non-conforming cases sooner.

MFC after:	3 days
Reported by:	Peter Holm <peter at holm dot cc>
2005-09-26 08:17:03 +00:00
Robert Watson
ee47648770 Lock the read socket receive buffer when frobbing the sb_state flag on
that socket during open, not the write socket receive buffer.  This
might explain clearing of the sb_state SB_LOCK flag seen occasionally
in soreceive() on fifos.

MFC after:	3 days
Spotted by:	ups
2005-09-25 19:52:09 +00:00
Robert Watson
5d3df5cc1b For reasons of consistency (and necessity), assert an exclusive vnode
lock on the fifo vnode in fifo_open(): we rely on the vnode lock to
serialize access to v_fifoinfo.

MFC after:	3 days
2005-09-23 12:39:51 +00:00
Robert Watson
7028887eac Add fi_sx, an sx lock to serialize I/O operations on the socket pair
underlying the POSIX fifo implementation.  In 6.x/7.x, fifo access is
moved from the VFS layer, where it was serialized using the vnode
lock, to the file descriptor layer, where access is protected by a
reference count but not serialized.  This exposed socket buffer
locking to high levels of parallelism in specific fifo workloads, such
as make -j 32, which expose as yet unresolved socket buffer bugs.

fi_sx re-adds serialization about the read and write routines,
although not paths that simply test socket buffer mbuf queue state,
such as the poll and kqueue methods.  This restores the extra locking
cost previously present in some cases, but is an effective workaround
for the instability that has been experienced.  This workaround should
be removed once the bug in socket buffer handling has been fixed.

Reported by:	kris, jhb, Julien Gabel <jpeg at thilelli dot net>,
		Peter Holm <peter at holm dot cc>, others
MFC after:	3 days
2005-09-22 10:51:12 +00:00
Robert Watson
526e258d3a Assert that (vp) is locked in fifo_close(), since we rely on the
exclusive vnode lock to synchronize the reference counts on struct
fifoinfo.

MFC after:	3 days
2005-09-18 10:44:50 +00:00
Robert Watson
ca17bccaa1 The socket pointers in fifoinfo are not permitted to be NULL, so
don't check if they are, it just confuses the fifo code more.

MFC after:	3 days
2005-09-15 15:45:34 +00:00
Robert Watson
447bbaa2cf Trim down now (believed to be) unused fifo_ioctl() and
fifo_kqfilter() VOP implementations, since they in theory are used
only on open file descriptors, in which case the ioctls are via
fifo_ioctl_f() and kqueue requests are via fifo_kqfilter_f().
Generate warnings if they are entered for now.  These printf()
calls should become panic() calls.

Annotate and re-implement fifo_ioctl_f(): don't arbitrarily
forward ioctls to the socket layer, only forward the ones we
explicitly support for fifos.  In the case of FIONREAD, don't
forward the request to the write socket on a read-write fifo, or
the read result is overwritten.  Annotate a nasty case for the
undefined POSIX O_RDWR on fifos, in which failure of the second
ioctl will result in the socket pair being in an inconsistent
state.

Assert copyright as I find myself rewriting non-trivial parts of
fifofs.

MFC after:	3 days
2005-09-13 17:46:48 +00:00
Robert Watson
8a22e151be As a result of kqueue locking work, socket buffer locks will always
be held when entering a kqueue filter for fifos via a socket buffer
event: as such, assert the lock unconditionally rather than acquiring
it conditionall.

MFC after:	3 days
2005-09-13 10:39:24 +00:00
Robert Watson
db7a6c2f43 Annotate two issues:
1) fifo_kqfilter() is not actually ever used, it likely should be GC'd.

2) fifo_kqfilter_f() doesn't implement EVFILT_VNODE, so detecting events
   on the underlying vnode for a fifo no longer works (it did in 4.x).
   Likely, fifo_kqfilter_f() should forward the request to the VFS using
   fp->f_vnode, which would work once fifo_kqfilter() was detached from
   the vnode operation vector (removing the fifo override).

Discussed with:	phk
2005-09-13 09:23:22 +00:00
Robert Watson
88f39e8e95 Introduce no-op nosup fifo kqueue filter and detach routine, which are
used when a read filter is requested on a write-only fifo descriptor, or
a write filter is requested on a read-only fifo descriptor.  This
permits the filters to be registered, but never raises the event, which
causes kqueue behavior for fifos to more closely match similar semantics
for poll and select, which permit testing for the condition even though
the condition will never be raised, and is consistent with POSIX's notion
that a fifo has identical semantics to a one-way IPC channel created
using pipe() on most operating systems.

The fifo regression test suite can now run to completion on HEAD without
errors.

MFC after:	3 days
2005-09-12 19:59:12 +00:00
Robert Watson
48afebb83d When a request is made to register a filter on a fifo that doesn't
apply to the fifo (i.e., not EVFILT_READ or EVFILT_WRITE), reject
it as EINVAL, not by returning 1 (EPERM).

MFC after:	3 days
2005-09-12 18:07:49 +00:00
Robert Watson
114538d85b Remove DFLAG_SEEKABLE from fifo file descriptors: fifos are not seekable
according to POSIX, not to mention the fact that it doesn't make sense
(and hence isn't really implemented).  This causes the fifo_misc
regression test to succeed.
2005-09-12 12:15:12 +00:00
Robert Watson
6dd84b0bdc Only poll the fifo for read events if the fifo is attached to a readable
file descriptor.  Otherwise, the read end of a fifo might return that it
is writable (which it isn't).

Only poll the fifo for write events if the fifo attached to a writable
file descriptor.  Otherwise, the write end of a fifo might return that
it is readable (which it isn't).

In the event that a file is FREAD|FWRITE (which is allowed by POSIX, but
has undefined behavior), we poll for both.

MFC after:	3 days
2005-09-12 10:16:18 +00:00
Robert Watson
845e8e827b After going to some trouble to identify only the write-related events
to poll the write socket for, the fifo polling code proceeded to poll
for the complete set of events.  Use 'levents' instead of 'events' as
the argument to poll, and only poll the write socket if there is
interest in write events.

MFC after:	3 days
2005-09-12 10:13:15 +00:00
Robert Watson
ab5182012a When a writer opens a fifo, wake up the read socket for read, not the
write socket.

MFC after:	3 days
2005-09-12 10:07:21 +00:00
Robert Watson
a1b9943657 Add an assertion that fifo_open() doesn't race against other threads
while sleeping to allocate fifo state: due to using the vnode lock to
serialize access to a fifo during open, it shouldn't happen (tm).

MFC after:	3 days
2005-09-12 10:06:38 +00:00