the lower layer needs to have control over that flag.
that didn't solve the whole problem that it was trying to solve anyway.
(the issue is that if we have create mappings to the lower layer,
we need to get rid of those when we copy the file to the upper layer.)
we'll have to figure out some other way to handle this.
between creation of a file descriptor and close(2) when using kernel
assisted threads. What we do is stick descriptors in the table, but
mark them as "larval". This causes essentially everything to treat
it as a non-existent descriptor, except for fdalloc(), which sees a
filled slot so that it won't (incorrectly) allocate it again. When
a descriptor is fully constructed, the code that has constructed it
marks it as "mature" (which actually clears the "larval" flag), and
things continue to work as normal.
While here, gather all the code that gets a descriptor from the table
into a fd_getfile() function, and call it, rather than having the
same (sometimes incorrect) code copied all over the place.
to resolve a write fault. fixes PR 13201.
also, be sure to allocate blocks for write faults to holes even if
the page is already in memory. fixes PR 13189.
- We need to skip PGO_DONTCARE page also.
- ``npages'' returned by VOP_GETPAGES for lower vp doesn't count
those pages in this case. So, just loop ``npages'' times is
insufficient. Loop while there is real pages instead.
callers and appropriate routines to cope. This makes fo_stat more
consistent with rest of fileops routines and also makes the fo_stat
match FreeBSD as an added bonus.
Discussed with Luke Mewburn on tech-kern@.
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.
setattr calls on underlying vnodes the same as sockets and just return 0.
This whole thing needs to be gutted and replaced with either fall throughs
to specfs (the attr forwarding is just bizarre and leads to weird crap like
the above truncation problems), or better yet a real cloning device node.
which we disallow creation of page cache pages) and its on-disk EOF
(which marks the offset at which there is not (yet) data on disk that
we need to read when creating pages). for requests with PGO_PASTEOF,
the in-memory EOF maybe be much larger than the on-disk EOF.
- in genfs_getpages(), unbusy any pages that we don't free in the error path.
- in genfs_putpages(), if we get a bmap error, record that in the master buf.
- 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.
- in the PGO_PASTEOF case, use the larger of the current file size and the
end of the requested range of pages as the file size for this request.
this fixes some problems with sparsing writes to large offsets.
chs