deadlock in VOP_FSYNC() if the unreferenced vnode picked for
reclamation happened to be stacked on top of a vnode the process
already had locked. This could happen if the same filesystem was
accessed both through a union mount and directly; it seemed to happen
most frequently when the direct access was through NFS.
Avoid this deadlock by changing vinvalbuf to pass a new FSYNC_RECLAIM
flag bit to VOP_FSYNC() to indicate that a reclaim is in progress and
only a `shallow' fsync is necessary.
Do nothing in *_fsync() in umapfs, nullfs, and unionfs when
FSYNC_RECLAIM is set; the underlying vnodes will shortly be released
in *_reclaim and may be reclaimed (and fsync'ed) later.
only benefit this provides is that we don't use kmem_map to map the memory
used for vnodes (though, this is a 30 virtual page savings on my PPro)
since vnodes are never freed (they have their own freelist).
* we already have the vnode interlock, so vref() should not ask for it again.
* we call VOP_RECLAIM/VOP_INACTIVE(), which shouldn't be duplicated in vrele().
UVM was written by chuck cranor <chuck@maria.wustl.edu>, with some
minor portions derived from the old Mach code. i provided some help
getting swap and paging working, and other bug fixes/ideas. chuck
silvers <chuq@chuq.com> also provided some other fixes.
this is the rest of the MI portion changes.
this will be KNF'd shortly. :-)
unmounting all of the file systems. If we encounter a condition where
all of the dirty buffers could not flush, then don't unmount file systems,
since it might be likely to wedge.
anon cred are the same. Should probably be handled better in the mountd,
but this will do for now. Fixes PR 469, submitted Sept 1994 by
a certain "Jason R. Thorpe".. ;-)
so that if the drop to spl0() causes another panic (e.g. because there's
still some fatal hardware interrupt that's pending) we'll know that we
dropped IPL to sync the disks.
* When a delayed write buffer falls off the LRU queue, arrange for it to go on
the AGE queue after being flushed out to disk.
* When a delayed write buffer is synced, leave it in its relative position in
the LRU queue.
work. Not quite as good as with the Lite2 merges, but it'll do until then.
* dounmount() expects to be called with the mountpoint marked busy
* all callers of dounmount() thus make the call themselves
* if a filesystem was being unmounted, and we're woken up in vfs_busy(),
don't reference the mountpoint struct pointer, as it has very probably
been freed.
mount the root file system. If the operator specified the root
file system type in the kernel configuration file, attempt to
mount that file system type on the root device. If the root
file system type was wildcarded (or unspecified), try all of
the file systems statically built into the kernel until one
succeeds. If no file systems succeed, return an error. The
system will recover from this condition.
- Implement vfs_getopsbyname(). This function returns the file
system ops vector given a file system name.
queue.h list/queue head initializer macros. mountlist was converted so
that panics (or other reboots) early on in kernel startup don't cause
sys_sync() to croak. vnode_free_list was converted because it was nearby.
