- if an operation (R, W, IOCTL) is non blocking, a flag is set
and sent to the device.
- nothing changes for sync devices
- asyn devices should reply asap if an operation is non-blocking.
We must trust the devices, but we had to trust them anyway to
reply to CANCEL correctly
- we safe sending CANCEL commands to asyn devices. This greatly
simplifies the protocol. Asynchronous devices can always reply
when a reply is ready and do not need to deal with other
situations
- currently, none of our drivers use the flags since they drive
virtual devices which do not block
- 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)
The NetBSD boot loader loads automatically the kernel module appropriate
for the detected root file system; it is preset at "ffs". The MINIX3fs
support does not reset the underlying global variable, since there are
no use for this on MINIX. As a result, the boot loader searches for
/ffs.kmod, and issues two warnings about "module failure to open/load."
When VFS detects that an FS has crashed and tries to clean up
resources, it marks fairly late in the process that a vmnt is not
to be used again (to send requests to). This allows a thread to
become blocked on a vmnt after all blocked threads were stopped, but
before it finds out it shouldn't try to send to that vmnt.
If the provided path was only a single component (i.e., without
slashes), then last_dir would return early and skip the symlink
detection (i.e., check whether the path ends in a symlink and resolve
that first before returning). This bug triggered an assert in open
which expects that an advance after an last_dir (with VMNT_WRITE lock)
does not yield another vmnt lock.
The assert was meant as an additional check to the assert in link.c:198.
The reasoning behind the assert in link.c:198 is that once you've
obtained a write lock on a vmnt, you can't get an additional read lock
on the same vmnt. However, that does not always hold for the assert in
path.c:281 where the situation could be that you've obtained a read lock
and managed to get another read lock (this is possible). In other words,
the assert in path.c:281 is not the right place to check for that
situation.
- 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.
. harmonize bsd.lib.mk and bsd.man.mk with netbsd files
. throw out minix section 3 (library calls) manpages,
replaced by netbsd ones that are now installed
