Commit graph

47 commits

Author SHA1 Message Date
David van Moolenbroek
723e51327f VFS: worker thread model overhaul
The main purpose of this patch is to fix handling of unpause calls
from PM while another call is ongoing. The solution to this problem
sparked a full revision of the threading model, consisting of a large
number of related changes:

- all active worker threads are now always associated with a process,
  and every process has at most one active thread working for it;
- the process lock is always held by a process's worker thread;
- a process can now have both normal work and postponed PM work
  associated to it;
- timer expiry and non-postponed PM work is done from the main thread;
- filp garbage collection is done from a thread associated with VFS;
- reboot calls from PM are now done from a thread associated with PM;
- the DS events handler is protected from starting multiple threads;
- support for a system worker thread has been removed;
- the deadlock recovery thread has been replaced by a parameter to the
  worker_start() function; the number of worker threads has
  consequently been increased by one;
- saving and restoring of global but per-thread variables is now
  centralized in worker_suspend() and worker_resume(); err_code is now
  saved and restored in all cases;
- the concept of jobs has been removed, and job_m_in now points to a
  message stored in the worker thread structure instead;
- the PM lock has been removed;
- the separate exec lock has been replaced by a lock on the VM
  process, which was already being locked for exec calls anyway;
- PM_UNPAUSE is now processed as a postponed PM request, from a thread
  associated with the target process;
- the FP_DROP_WORK flag has been removed, since it is no longer more
  than just an optimization and only applied to processes operating on
  a pipe when getting killed;
- assignment to "fp" now takes place only when obtaining new work in
  the main thread or a worker thread, when resuming execution of a
  thread, and in the special case of exiting processes during reboot;
- there are no longer special cases where the yield() call is used to
  force a thread to run.

Change-Id: I7a97b9b95c2450454a9b5318dfa0e6150d4e6858
2014-02-18 11:25:03 +01:00
David van Moolenbroek
f707937192 VFS: process char driver replies from main thread
Previously, processing of some replies coming from character drivers
could block on locks, and therefore, such processing was done from
threads that were associated to the character driver process. The
hidden consequence of this was that if all threads were in use, VFS
could drop replies coming from the driver. This patch returns VFS to
a situation where the replies from character drivers are processed
instantly from the main thread, by removing the situations that may
cause VFS to block while handling those replies.

- change the locking model for select, so that it will never block
  on any processing that happens after the select call has been set
  up, in particular processing of character driver select replies;
- clearly mark all select routines that may never block;
- protect against race conditions in do_select as result of the
  locking that still does happen there (as is required for pipes);
- also handle select timers from the main thread;
- move processing of character driver replies into device.c.

Change-Id: I4dc8e69f265cbd178de0fbf321d35f58f067cc57
2014-02-18 11:25:03 +01:00
David van Moolenbroek
2e9f4d0198 VFS: properly cancel select queries on unpause
Change-Id: I16e71db3f5c1bcc7ba6045bc9f02b13d71dc31eb
2014-02-18 11:25:03 +01:00
David van Moolenbroek
87aefd7eb2 VFS: remove support for sync char driver protocol
Change-Id: I57cc870a053b813b3a3fc45da46606ea84fe4cb1
2014-02-18 11:25:03 +01:00
David van Moolenbroek
6331e8f845 Retire the synchronous character driver protocol
- change all sync char drivers into async drivers;
- retire support for the sync protocol in libchardev;
- remove async dev style, as this is now the default;
- remove dev_status from VFS;
- clean up now-unused protocol messages.

Change-Id: I6aacff712292f6b29f2ccd51bc1e7d7003723e87
2014-02-18 11:25:02 +01:00
Thomas Veerman
32e916ad53 VFS: use 64-bit file offsets in all requests
Change-Id: I735c4068135474aff2c397f4bc9fb147a618b453
2014-02-18 11:25:01 +01:00
Ben Gras
456359aa72 retire 64-bit conversion functions
Change-Id: Ib6b81403f877c363a286c654e0524fa1cb781b80
2013-06-24 16:50:57 +02:00
Ben Gras
cef94e096e vfs: make m_out non-global
m_out is shared between threads as the reply message, and it can happen
results get overwritten by another thread before the reply is sent. This
change

	. makes m_out local to the message handling function,
	  declared on the stack of the caller
	. forces callers of reply() to give it a message, or
	  declare the reply message has no significant fields except
	  for the return code by calling replycode()

Change-Id: Id06300083a63c72c00f34f86a5c7d96e4bbdf9f6
2013-04-12 23:40:38 +00:00
Thomas Veerman
fa78dc389f socket: implement SOCK_CLOEXEC and SOCK_NONBLOCK
Change-Id: I3fa36fa999c82a192d402cb4d913bd397e106e53
2013-02-28 10:08:53 +00:00
Lionel Sambuc
f640210005 Removing obsolete _NBSD_LIBC define
Change-Id: Ia6ce84ccdf36cf6f64540b990baaa7d85c53533d
2013-02-26 09:44:24 +00:00
Thomas Veerman
06e2adbeaa VFS: fix select again
Change-Id: Ia5e26cdbfe38e3fb293dd57269a76b15c1fe236b
2013-01-25 17:42:36 +00:00
Thomas Veerman
306f3ccd6f VFS: fix select bug on pipes 2013-01-23 11:14:34 +00:00
Thomas Veerman
3de8d1cf6e VFS/PFS: remove notion of position in pipes
Because pipes have no file position. VFS maintained (file) offsets into a
buffer internal to PFS and stored them in vnodes for simplicity, mixing
the responsibilities of filp and vnode objects.

With this patch PFS ignores the position field in REQ_READ and REQ_WRITE
requests making VFS' job a lot simpler.
2013-01-11 09:18:35 +00:00
Thomas Veerman
992799b91f VFS: make all IPC asynchronous
By decoupling synchronous drivers from VFS, we are a big step closer to
supporting driver crashes under all circumstances. That is, VFS can't
become stuck on IPC with a synchronous driver (e.g., INET) and can
recover from crashing block drivers during open/close/ioctl or during
communication with an FS.

In order to maintain serialized communication with a synchronous driver,
the communication is wrapped by a mutex on a per driver basis (not major
numbers as there can be multiple majors with identical endpoints). Majors
that share a driver endpoint point to a single mutex object.

In order to support crashes from block drivers, the file reopen tactic
had to be changed; first reopen files associated with the crashed
driver, then send the new driver endpoint to FSes. This solves a
deadlock between the FS and the block driver;
  - VFS would send REQ_NEW_DRIVER to an FS, but he FS only receives it
    after retrying the current request to the newly started driver.
  - The block driver would refuse the retried request until all files
    had been reopened.
  - VFS would reopen files only after getting a reply from the initial
    REQ_NEW_DRIVER.

When a character special driver crashes, all associated files have to
be marked invalid and closed (or reopened if flagged as such). However,
they can only be closed if a thread holds exclusive access to it. To
obtain exclusive access, the worker thread (which handles the new driver
endpoint event from DS) schedules a new job to garbage collect invalid
files. This way, we can signal the worker thread that was talking to the
crashed driver and will release exclusive access to a file associated
with the crashed driver and prevent the garbage collecting worker thread
from dead locking on that file.

Also, when a character special driver crashes, RS will unmap the driver
and remap it upon restart. During unmapping, associated files are marked
invalid instead of waiting for an endpoint up event from DS, as that
event might come later than new read/write/select requests and thus
cause confusion in the freshly started driver.

When locking a filp, the usage counters are no longer checked. The usage
counter can legally go down to zero during filp invalidation while there
are locks pending.

DS events are handled by a separate worker thread instead of the main
thread as reopening files could lead to another crash and a stuck thread.
An additional worker thread is then necessary to unlock it.

Finally, with everything asynchronous a race condition in do_select
surfaced. A select entry was only marked in use after succesfully sending
initial select requests to drivers and having to wait. When multiple
select() calls were handled there was opportunity that these entries
were overwritten. This had as effect that some select results were
ignored (and select() remained blocking instead if returning) or do_select
tried to access filps that were not present (because thrown away by
secondary select()). This bug manifested itself with sendrecs, but was
very hard to reproduce. However, it became awfully easy to trigger with
asynsends only.
2012-09-17 11:01:45 +00:00
Ben Gras
0fb2f83da9 drop from segments physcopy/vircopy invocations
. sys_vircopy always uses D for both src and dst
	. sys_physcopy uses PHYS_SEG if and only if corresponding
	  endpoint is NONE, so we can derive the mode (PHYS_SEG or D)
	  from the endpoint arg in the kernel, dropping the seg args
	. fields in msg still filled in for backwards compatability,
	  using same NONE-logic in the library
2012-06-18 12:28:40 +00:00
Thomas Veerman
db8198d99d VFS: use S_IS* macros 2012-04-27 08:49:38 +00:00
Thomas Veerman
96bbc5da3e VFS: I_PIPE is redundant
Also, use S_IS* macros instead of manual comparison.
2012-04-27 08:49:38 +00:00
Thomas Veerman
b956493367 VFS: fix new signed/unsigned comparisons 2012-04-13 13:00:11 +00:00
Thomas Veerman
8f55767619 VFS: make m_in job local
By making m_in job local (i.e., each job has its own copy of m_in instead
of refering to the global m_in) we don't have to store and restore m_in
on every thread yield. This reduces overhead. Moreover, remove the
assumption that m_in is preserved. Do_XXX functions have to copy the
system call parameters as soon as possible and only pass those copies to
other functions.

Furthermore, this patch cleans up some code and uses better types in a lot
of places.
2012-04-13 12:50:38 +00:00
Ben Gras
7336a67dfe retire PUBLIC, PRIVATE and FORWARD 2012-03-25 21:58:14 +02:00
Ben Gras
6a73e85ad1 retire _PROTOTYPE
. only good for obsolete K&R support
	. also remove a stray ansi.h and the proto cmd
2012-03-25 16:17:10 +02:00
Tomas Hruby
f19d8df184 VFS : simplification of handling asyn selects
- select_request_async() returns no ops by default

- wantops in do_select() always set correctly, do_select() does
  not need a special case for SUSPEND (and ugly code)
2012-03-02 15:44:48 +00:00
Thomas Veerman
c540bcb001 VFS: various select fixes
- Fix locking bug when unable to send DEV_SELECT request. Upon failure
  VFS tried to cancel the select operation, but this failed due to trying
  to lock a filp that was already locked to send the request in the first
  place. Do_select_request now handles locking of filps itself instead of
  relying on the caller to do it.  This fixes a crash when killing INET.
- Fix failure to revive a process after a non-blocking select operation
  yielded no ready select operations when replying DEV_SEL_REPL1.
- Improve readability by using OK, SUSPEND, and standard error values as
  results instead of having separate macros in select.
- Don't print not having a driver for a major device; after killing a driver
  select will trigger this printf.
2012-02-17 21:09:07 +00:00
Thomas Veerman
80c4685324 VFS: replace VFS with AVFS 2012-02-13 16:53:21 +00:00
Thomas Veerman
d4b72e81b2 Cleanup servers to make GCC/Clang a little happier 2011-09-08 13:57:03 +00:00
Thomas Veerman
902e0e27e0 Don't panic if owner has vanished before reply 2011-07-15 14:11:34 +00:00
Gianluca Guida
cc17b27a2b Build NetBSD libc library in world in ELF mode.
3 sets of libraries are built now:
  . ack: all libraries that ack can compile (/usr/lib/i386/)
  . clang+elf: all libraries with minix headers (/usr/lib/)
  . clang+elf: all libraries with netbsd headers (/usr/netbsd/)

Once everything can be compiled with netbsd libraries and headers, the
/usr/netbsd hierarchy will be obsolete and its libraries compiled with
netbsd headers will be installed in /usr/lib, and its headers
in /usr/include. (i.e. minix libc and current minix headers set
will be gone.)

To use the NetBSD libc system (libraries + headers) before
it is the default libc, see:
   http://wiki.minix3.org/en/DevelopersGuide/UsingNetBSDCode
This wiki page also documents the maintenance of the patch
files of minix-specific changes to imported NetBSD code.

Changes in this commit:
  . libsys: Add NBSD compilation and create a safe NBSD-based libc.
  . Port rest of libraries (except libddekit) to new header system.
  . Enable compilation of libddekit with new headers.
  . Enable kernel compilation with new headers.
  . Enable drivers compilation with new headers.
  . Port legacy commands to new headers and libc.
  . Port servers to new headers.
  . Add <sys/sigcontext.h> in compat library.
  . Remove dependency file in tree.
  . Enable compilation of common/lib/libc/atomic in libsys
  . Do not generate RCSID strings in libc.
  . Temporarily disable zoneinfo as they are incompatible with NetBSD format
  . obj-nbsd for .gitignore
  . Procfs: use only integer arithmetic. (Antoine Leca)
  . Increase ramdisk size to create NBSD-based images.
  . Remove INCSYMLINKS handling hack.
  . Add nbsd_include/sys/exec_elf.h
  . Enable ELF compilation with NBSD libc.
  . Add 'make nbsdsrc' in tools to download reference NetBSD sources.
  . Automate minix-port.patch creation.
  . Avoid using fstavfs() as it is *extremely* slow and unneeded.
  . Set err() as PRIVATE to avoid name clash with libc.
  . [NBSD] servers/vm: remove compilation warnings.
  . u32 is not a long in NBSD headers.
  . UPDATING info on netbsd hierarchy
  . commands fixes for netbsd libc
2011-06-24 11:46:30 +02:00
Ben Gras
a77c2973b3 fix clang warnings -R in kernel/ and servers/ 2011-06-09 16:09:13 +02:00
Thomas Veerman
aba392e630 Clean up and fix multiple bugs in select:
- Remove redundant code.
 - Always wait for the initial reply from an asynchronous select request,
   even if the select has been satisfied on another file descriptor or
   was canceled due to a serious error.
 - Restart asynchronous selects if upon reply from the driver turns out
   that there are deferred operations (and do not forget we're still
   interested in the results of the deferred operations).
 - Do not hang a non-blocking select when another blocking select on
   the same filp is still blocking.
 - Split blocking operations in read, write, and exceptions (i.e.,
   blocking on read does not imply the write will block as well).
 - Some loops would iterate over OPEN_MAX file descriptors instead of
   the "highest" file descriptor.
 - Use proper internal error return values.
 - A secondary reply from a synchronous driver is essentially the same
   as from an asynchronous driver (the only difference being how the 
   answer is received). Merge.
 - Return proper error code after a driver failure.
 - Auto-detect whether a driver is synchronous or asynchronous.
 - Remove some code duplication.
 - Clean up code (coding style, add missing comments, put all select
   related code together).
2011-04-13 13:25:34 +00:00
Erik van der Kouwe
36f9c1155a Restart process after response from async driver on non-blocking select 2011-02-23 10:27:48 +00:00
Erik van der Kouwe
9235536f38 Fix select-related bugs: missing cancellations led to potentially forgetting notifies, especially in the case of async drivers 2010-10-08 12:50:52 +00:00
Thomas Veerman
5aff633a0b Make RS and VFS aware of new UDS major. Contributed by Thomas Cort 2010-07-15 13:51:38 +00:00
David van Moolenbroek
895850b8cf move timers code to libsys 2010-07-09 12:58:18 +00:00
Tomas Hruby
6e25ad8b0a Use of all NIL_* defines converted to NULL 2010-05-10 13:26:00 +00:00
Kees van Reeuwijk
fc7dced1fa Fix printfs with too few or too many parms, remove unused vars, fix incorrect flag tests, other code cleanup. 2010-04-01 13:25:05 +00:00
Kees van Reeuwijk
c33102ea6b Miscellaneous code cleanup. 2010-03-22 20:43:06 +00:00
Ben Gras
35a108b911 panic() cleanup.
this change
   - makes panic() variadic, doing full printf() formatting -
     no more NO_NUM, and no more separate printf() statements
     needed to print extra info (or something in hex) before panicing
   - unifies panic() - same panic() name and usage for everyone -
     vm, kernel and rest have different names/syntax currently
     in order to implement their own luxuries, but no longer
   - throws out the 1st argument, to make source less noisy.
     the panic() in syslib retrieves the server name from the kernel
     so it should be clear enough who is panicing; e.g.
         panic("sigaction failed: %d", errno);
     looks like:
         at_wini(73130): panic: sigaction failed: 0
         syslib:panic.c: stacktrace: 0x74dc 0x2025 0x100a
   - throws out report() - printf() is more convenient and powerful
   - harmonizes/fixes the use of panic() - there were a few places
     that used printf-style formatting (didn't work) and newlines
     (messes up the formatting) in panic()
   - throws out a few per-server panic() functions
   - cleans up a tie-in of tty with panic()

merging printf() and panic() statements to be done incrementally.
2010-03-05 15:05:11 +00:00
Kees van Reeuwijk
1597e701a0 Remove useless variables and the computations on them. 2010-02-19 10:00:32 +00:00
Thomas Veerman
958b25be50 - Introduce support for sticky bit.
- Revise VFS-FS protocol and update VFS/MFS/ISOFS accordingly.
- Clean up MFS by removing old, dead code (backwards compatibility is broken by
  the new VFS-FS protocol, anyway) and rewrite other parts. Also, make sure all
  functions have proper banners and prototypes.
- VFS should always provide a (syntactically) valid path to the FS; no need for
  the FS to do sanity checks when leaving/entering mount points.
- Fix several bugs in MFS:
  - Several path lookup bugs in MFS.
  - A link can be too big for the path buffer.
  - A mountpoint can become inaccessible when the creation of a new inode
    fails, because the inode already exists and is a mountpoint.
- Introduce support for supplemental groups.
- Add test 46 to test supplemental group functionality (and removed obsolete
  suppl. tests from test 2).
- Clean up VFS (not everything is done yet).
- ISOFS now opens device read-only. This makes the -r flag in the mount command
  unnecessary (but will still report to be mounted read-write).
- Introduce PipeFS. PipeFS is a new FS that handles all anonymous and
  named pipes. However, named pipes still reside on the (M)FS, as they are part
  of the file system on disk. To make this work VFS now has a concept of
  'mapped' inodes, which causes read, write, truncate and stat requests to be
  redirected to the mapped FS, and all other requests to the original FS.
2009-12-20 20:27:14 +00:00
Tomas Hruby
8590ac260d Removed dependency of vfs on NR_TASKS macro
- all macros in consts.h that depend on NR_TASKS replaced by a FP_BLOCKED_ON_*

- fp_suspended removed and replaced by fp_blocked_on. Testing whether a process
  is supended is qeual to testing whether fp_blocked_on is FP_BLOCKED_ON_NONE or
  not

- fp_task is valid only if fp_blocked_on == FP_BLOCKED_ON_OTHER

- no need of special values that do not colide with valid and special endpoints
  since they are not used as endpoints anymore

- suspend only takes FP_BLOCKED_ON_* values not endpoints anymore

- suspend(task) replaced by wait_for(task) which sets fp_task so we remember who
  are we waiting for and suspend sets fp_blocked_on to FP_BLOCKED_ON_OTHER to
  signal that we are waiting for some other process

- some functions should take endpoint_t instead of int, fixed
2009-09-22 21:48:26 +00:00
Ben Gras
834d9d34e8 Initialize deferred field. This seems to fix a hanging select() bug. 2008-12-17 14:20:08 +00:00
Ben Gras
7d674f4b8e no more HZ; less debugging statements 2008-12-11 14:47:48 +00:00
Philip Homburg
bc7e3c02a3 Asynchronous select implementation. 2008-02-22 15:46:59 +00:00
Philip Homburg
4b1cd8c0ec Return EIO if a filedescriptor cannot be re-opened after a driver restart.
Select now returns such a filedescriptor as ready (instead of EBADF). 
Reply before dev_up in FSSIGNON to avoid the problem that a DEV_OPEN
request is received by a driver that expects a reply from the FSSIGNON.
2007-08-15 12:53:52 +00:00
Ben Gras
8ea438ae93 Retired DEV_{READ,WRITE,GATHER,SCATTER,IOCTL} (safe versions *_S are to
be used and drivers should never receieve these 'unsafe' variants
any more).
2007-02-07 16:22:19 +00:00
Philip Homburg
bafc45a309 First cut at 64-bit file offsets in block devices for mkfs/fsck. 2006-11-27 14:21:43 +00:00
Ben Gras
fa0ba56bc9 Merge of VFS by Balasz Gerofi with Minix trunk. 2006-10-25 13:40:36 +00:00
Renamed from servers/fs/select.c (Browse further)