a driver selectable callback function. This is used in the Xen port to
allow controlling the domain's network setup from the domain building
environment at domain creation (vs. having to maintain/change this on a
dhcp server). The Xen network driver parses a command line passed in
from the domain builder.
already being locked by our thread. VOP_INACTIVATE() makes no
statement as to the lock state of the parent, yet this code assumed
we had it unlocked.
With this change, we let vn_lock() fail with EDEADLK if we already
have the parent locked. We then handle the rename cleanup, and on
the way out just vrele() the parent vnode, not vput() it.
Fixes a case seen by Steve Woodford at Wasabisystems dot com where
we'd panic while running a pkgsrc configure test that verified
fork() functionality. I expect the problem is a result of the recent
exit() changes and the performance of the machines he tested on.
Specifically we would crash during an nfs_remove(). As best I can
tell, when nfs_remove() tested to see if we should rename or we
should remove, v_usecount was > 1 and vattr.va_nlink was 1. Thus
we did the sillyrename in nfs_remove(). However by the time we got
down to the vput(vp), v_usecount had dropped to one and thus vput()
triggered the VOP_INACTIVATE() code path. nfs_inactive() tries to
lock the parent to undo the sillyrename, and deadlocks as we still
have it locked.
is opened. An open file can always be read from and/or written to,
depending on how it was opened.
Therefore, the read/write/commit RPCs should never return EACCESS,
as they are only performed on files that have been successfully opened
already.
This change improves the current situation and works in most cases.
It simply always uses the most recently known owner/group of the file,
iff the authentication mechanism is AUTH_UNIX (in other cases, the
creds for a succesful open are used, but note that no other cases
are currently implemented).
A retry mechanism can be used to catch a few more cases, but this is
a good improvement for now.
Increase NFS_MAXRAHEAD to 32. With 32k read or write requests, that
amounts to 1 Mbyte of read-ahead, enough to cover about 10 ms latency
at gigabit Ethernet speeds. Increase the table of nfsiod kthreads
(NFS_MAXASYNCDAEMON) from 20 to 128, to match the raised value of
NFS_MAXRAHEAD. (Making the limit dynamic requires replacing the
compile-time array with a dynamic structure.)
Add a comment explaining that each read-ahead requires an I/O thread.
Wrap both parameters with an #ifdef <parameter>/#endif, to allow
hand-tuned values or (later) a kernel config-file option override.
Gone are the old kern_sysctl(), cpu_sysctl(), hw_sysctl(),
vfs_sysctl(), etc, routines, along with sysctl_int() et al. Now all
nodes are registered with the tree, and nodes can be added (or
removed) easily, and I/O to and from the tree is handled generically.
Since the nodes are registered with the tree, the mapping from name to
number (and back again) can now be discovered, instead of having to be
hard coded. Adding new nodes to the tree is likewise much simpler --
the new infrastructure handles almost all the work for simple types,
and just about anything else can be done with a small helper function.
All existing nodes are where they were before (numerically speaking),
so all existing consumers of sysctl information should notice no
difference.
PS - I'm sorry, but there's a distinct lack of documentation at the
moment. I'm working on sysctl(3/8/9) right now, and I promise to
watch out for buses.
local-loopback (lo0). As posted for review on tech-kern 2003-18-09,
with a long comment explaining (one of) the deadlock scenarios.
I've used this since shortly after 2002-09-12-, without noticing
performance degradataion or instability for non-loopback mounts.
previous error conditions.
If "(flags & (V_WAIT|V_PCATCH)) == V_WAIT" the return value is always zero.
Ignore the return value in these cases.
From Darrin B. Jewell.
file system.
The function vfs_write_suspend stops all new write operations to a file
system, allows any file system modifying system calls already in progress
to complete, then sync's the file system to disk and returns. The
function vfs_write_resume allows the suspended write operations to
complete.
From FreeBSD with slight modifications.
Approved by: Frank van der Linden <fvdl@netbsd.org>
it has a bug in the backoff calculation. so,
- clip it to 1-60 sec. (suggested by Rick Macklem)
- use a constant multiplier instead of nfs_backoff, which
is already exponential.
- move some related constant definations to nfs.h from nqnfs.h and
prefix with NFS_ instead of NQ_ because they are not nqnfs-specific.
