Remove M_TRYWAIT/M_WAITOK/M_WAIT. Callers should use 0.
Merge M_NOWAIT/M_DONTWAIT into a single flag M_NOWAIT.

Close the remaining user address mapping races for physical
I/O, CAM, and AIO. Still TODO: streamline useracc() checks.

Reviewed by: alc, tegge
MFC after: 7 days

- Hold the page queues lock around vm_page_hold().
- Assert that the page queues lock rather than Giant is held in
vm_page_hold().

Fix two long-standing, but likely harmless, errors in the use of
vm_pageout_deficit:
1. Update vm_pageout_deficit before VM_WAIT. There is no sense in
delaying the update; the sooner the pageout

Fix two long-standing, but likely harmless, errors in the use of
vm_pageout_deficit:
1. Update vm_pageout_deficit before VM_WAIT. There is no sense in
delaying the update; the sooner the pageout daemon receives this
information the better. Reviewed by: tegge
2. Update vm_pageout_deficit according to the number of pages still
needed to complete the allocation, not the original size of the
allocation. Submitted by: tegge

(These errors have existed since the introduction of vm_pageout_deficit
in revision 1.144.)

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Merge all the various copies of vmapbuf() and vunmapbuf() into a single
portable copy. Note that pmap_extract() must be used instead of
pmap_kextract().

This is precursor work to a reorganization o

Merge all the various copies of vmapbuf() and vunmapbuf() into a single
portable copy. Note that pmap_extract() must be used instead of
pmap_kextract().

This is precursor work to a reorganization of vmapbuf() to close remaining
user/kernel races (which can lead to a panic).

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- Update vm_pageout_deficit using atomic operations. It's a simple
counter outside the scope of existing locks.
- Eliminate a redundant clearing of vm_pageout_deficit.

vm_hold_load_pages() needn't clear PG_ZERO because it didn't pass
VM_ALLOC_ZERO to vm_page_alloc(). (PG_ZERO is clear by default.)

Make bogus_offset local to bufinit().

Fix cut&paste bug which would result in a panic because buffer was
being biodone'ed multiple times.

Allocate bogus_page with VM_ALLOC_WIRED. (Previously, bogus_page's
allocation incremented the global count of wired pages, but not the
page's own wire count. This inconsistency was introduced in
re

Allocate bogus_page with VM_ALLOC_WIRED. (Previously, bogus_page's
allocation incremented the global count of wired pages, but not the
page's own wire count. This inconsistency was introduced in
revision 1.230.)

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Temporarily introduce a new VOP_SPECSTRATEGY operation while I try
to sort out disk-io from file-io in the vm/buffer/filesystem space.

The intent is to sort VOP_STRATEGY calls into those which opera

Temporarily introduce a new VOP_SPECSTRATEGY operation while I try
to sort out disk-io from file-io in the vm/buffer/filesystem space.

The intent is to sort VOP_STRATEGY calls into those which operate
on "real" vnodes and those which operate on VCHR vnodes. For
the latter kind, the call will be changed to VOP_SPECSTRATEGY,
possibly conditionally for those places where dual-use happens.

Add a default VOP_SPECSTRATEGY method which will call the normal
VOP_STRATEGY. First time it is called it will print debugging
information. This will only happen if a normal vnode is passed
to VOP_SPECSTRATEGY by mistake.

Add a real VOP_SPECSTRATEGY in specfs, which does what VOP_STRATEGY
does on a VCHR vnode today.

Add a new VOP_STRATEGY method in specfs to catch instances where
the conversion to VOP_SPECSTRATEGY has not yet happened. Handle
the request just like we always did, but first time called print
debugging information.

Apart up to two instances of console messages per boot, this amounts
to a glorified no-op commit.

If you get any of the messages on your console I would very much
like a copy of them mailed to phk@freebsd.org

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Don't call VOP_BMAP on VCHR vnodes when the logical and physical block
numbers are identical: it cannot even hope to accomplish anything.

Convert calls to BUF_STRATEGY to VOP_STRATEGY calls. This is a no-op since
all BUF_STRATEGY did in the first place was call VOP_STRATEGY.

Correct typos, mostly s/ a / an / where appropriate. Some whitespace cleanup,
especially in troff files.

Hold the page queues lock when calling vm_page_flag_clear().

- Hold the kernel_object's lock around vm_page_alloc(kernel_object,...).
- Hold the page queues lock around vm_page_wakeup().

The buffer daemon cannot skip over buffers owned by locked inodes as
they may be the only viable ones to flush. Thus it will now wait for
an inode lock if the other alternatives will result in rollba

The buffer daemon cannot skip over buffers owned by locked inodes as
they may be the only viable ones to flush. Thus it will now wait for
an inode lock if the other alternatives will result in rollbacks (and
immediate redirtying of the buffer). If only buffers with rollbacks
are available, one will be flushed, but then the buffer daemon will
wait briefly before proceeding. Failing to wait briefly effectively
deadlocks a uniprocessor since every other process writing to that
filesystem will wait for the buffer daemon to clean up which takes
close enough to forever to feel like a deadlock.

Reported by: Archie Cobbs <archie@dellroad.org>
Sponsored by: DARPA & NAI Labs.
Approved by: re

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Hold the page queues/flags lock when calling vm_page_set_validclean().

Approved by: re

Now that pmap_remove_all() is exported by our pmap implementations
use it directly.

When prot is VM_PROT_NONE, call pmap_page_protect() directly rather than
indirectly through vm_page_protect(). The one remaining page flag that
is updated by vm_page_protect() is already being updat

When prot is VM_PROT_NONE, call pmap_page_protect() directly rather than
indirectly through vm_page_protect(). The one remaining page flag that
is updated by vm_page_protect() is already being updated by our various
pmap implementations.

Note: A later commit will similarly change the VM_PROT_READ case and
eliminate vm_page_protect().

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When the number of dirty buffers rises too high, the buf_daemon runs
to help clean up. After selecting a potential buffer to write, this
patch has it acquire a lock on the vnode that owns the buffer

When the number of dirty buffers rises too high, the buf_daemon runs
to help clean up. After selecting a potential buffer to write, this
patch has it acquire a lock on the vnode that owns the buffer before
trying to write it. The vnode lock is necessary to avoid a race with
some other process holding the vnode locked and trying to flush its
dirty buffers. In particular, if the vnode in question is a snapshot
file, then the race can lead to a deadlock. To avoid slowing down the
buf_daemon, it does a non-blocking lock request when trying to lock
the vnode. If it fails to get the lock it skips over the buffer and
continues down its queue looking for buffers to flush.

Sponsored by: DARPA & NAI Labs.

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Remove unused includes.
Clarify the intention of a while();
Move a local variable to avoid potential name-confusion.

Be consistent about "static" functions: if the function is marked
static in its prototype, mark it static at the definition too.

Inspired by: FlexeLint warning #512

Correctly order VI_UNLOCK(), local variables and block comment.

Make biowait() check bio_error before the BIO_ERROR flag, to propery
catch internal GEOM use of bio_error.

Sponsored by: DARPA & NAI Labs.