the mapping is:
VM_PAGER_OK 0
VM_PAGER_BAD <unused>
VM_PAGER_FAIL <unused>
VM_PAGER_PEND 0 (see below)
VM_PAGER_ERROR EIO
VM_PAGER_AGAIN EAGAIN
VM_PAGER_UNLOCK EBUSY
VM_PAGER_REFAULT ERESTART
for async i/o requests, it used to be possible for the request to
be convert to sync, and the pager would return VM_PAGER_OK or VM_PAGER_PEND
to indicate whether the caller should perform post-i/o cleanup.
this is no longer allowed; pagers must now return 0 to indicate that
the async i/o was successfully started, and the caller never needs to
worry about doing the post-i/o cleanup.
- in the cases where we skip over the i/o loop, increment npages by ridx
so that when the cleanup code starts processing the pgs array at index 0
it'll actually process all of the pages.
- process the PG_RELEASED flag when unbusying pages.
- add some missing MP locking.
- use MIN() and MAX() instead of min() and max() since the latter are
functions which take arguments of type "int" but we call them with
values of type "off_t", so the values could be truncated.
problem reported by msaitoh@netbsd.org. NOTE: These are marked XXXUBC
since the code that allocates the bufs is new with UBC, but it may be
the case that bp->b_proc needs to be intialized to curproc (it's used
in a call to nfs_sigintr()).
- fix math when skipping writing pages that just need a commit.
- clear the needcommit stuff and PG_RDONLY flags on pages returned for
overwrite requests as well as for normal write faults.
- bail out of nfs_write() if we get an error.
- remove a bogus attempt to clean up after failed uiomove()s.
- bring over a workaround for a lock-ordering problem from the genfs code.
- add some missing MP locking.
passed it down to the appropriate usrreq function, and this
allows usage for contexts that need to be explicitly different
from curproc (like in the NFS code when binding to a reserved port).
if we do this for VBLK vnodes which are in use by softdep mounts,
brelse() will mark the buffer B_INVAL as well, which makes the
softdep code very unhappy.
havoc if the server erroneously uses the same filehandle for
different files. This changes back revision 1.28; the PR that
that revision fixed doesn't apply anymore, it has been verified
not to be a problem with this change.
