back in rev. 1.51, bread() and breadn() were changed to assume that
if B_DONE is set on a buffer returned by bio_doread(), that the buffer
must have already been in the cache, and thus the overall bread() should
return success. but if the requested buffer is not in the cache and
is past the end of the device, bounds_check_with_label() will set B_ERROR
on the buffer and the caller will call biodone(), which will cause bread()
to think the buffer was already in the cache and thus return success.
to fix this, undo rev. 1.51 and instead have biowait() treat both B_DONE
and B_DELWRI as indicators that it doesn't need to sleep waiting for an
i/o to complete.
deal with shortages of the VM maps where the backing pages are mapped
(usually kmem_map). Try to deal with this:
* Group all information about the backend allocator for a pool in a
separate structure. The pool references this structure, rather than
the individual fields.
* Change the pool_init() API accordingly, and adjust all callers.
* Link all pools using the same backend allocator on a list.
* The backend allocator is responsible for waiting for physical memory
to become available, but will still fail if it cannot callocate KVA
space for the pages. If this happens, carefully drain all pools using
the same backend allocator, so that some KVA space can be freed.
* Change pool_reclaim() to indicate if it actually succeeded in freeing
some pages, and use that information to make draining easier and more
efficient.
* Get rid of PR_URGENT. There was only one use of it, and it could be
dealt with by the caller.
From art@openbsd.org.
since bounds_check_with_label() will truncate a buffer that crosses
the end of the partition. adjust the assertion to account for this.
fixes PRs 7938, 12156, 12698, 13076, 13210 and 13288.
return NULL instead of restarting the loop since we might sleep
while starting the i/o. this tells getblk() to check if someone else
created the buffer while we slept. from OpenBSD.
to be back on the AGE queue. Otherwise we risk recycling a set
of buffers with (soft) dependencies on the AGE list, which may
last forever if the vnode they belong to is locked (i.e. the syncer
won't get to the buffers they depend on, so their dependencies
are never flushed).
default, as the copyright on the main file (ffs_softdep.c) is such
that is has been put into gnusrc. options SOFTDEP will pull this
in. This code also contains the trickle syncer.
Bump version number to 1.4O
* Change the usage of B_DONE so that it is only set when a buffer is in sync
with the data on disk.
* If a buffer is being waited for, don't put it on the age queue.
* Make sure to clear B_DONE when pages are stolen from a buffer.
* Make sure to clear B_CACHE after each use.
* If we find a buffer for the block we want with valid data, but it is too
small, panic. (This isn't supposed to happen.)
Fixes potential file corruption problems with clustering.
`b_dev' value of NODEV happens and is normal if the buffer is on its way
to the underlying device strategy function for the first time.
Also, MFS sillily uses a major device number (255) which cannot be used
to index bdevsw[]. Check marked with XXXs.
call biowait() but return `success' immediately. We can return `success'
because buffers with recorded errors are not returned by getblk().
(Takes care of PR#3694).
* 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.
of using it directly, use a local, and set that local to be curproc
if curproc is not NULL else a pointer to process 0's proc struct.
If syncing disks while handling a panic that occurred while 'curproc'
was NULL, the old code would dereference NULL and die.
delayed write is logically converted to a sync write, mirroring the async case.
In bdwrite(), move the tape case earlier to avoid needless reassignbuf()s.
bawrite(). it's logically more correct (doesn't return an error code,
because it's async; bdwrite is also async), it still writes things
in-order, it makes sure the proper accountins is done (see the
wasdelayed cases in bwrite()), and it allows writes to vnodes on volumes
mountd with the MNT_ASYNC to be converted into delayed writes the way
God, err, Kirk intended. Convert synchronous bwrite()s on MNT_ASYNC
file systems to delayed writes.
explained in comments), which can cause a race condition. amazingly,
the _only_ time i've ever seen or heard of this problem was in some
comments and sources by Rick Macklem, and when running against the
a DEC OSF/1 NFS server running on an Alpha.
