to sleep). Locking 101, part 2: do not look at buffer contents after
you have been asleep. There is no telling what wonderous changes may
have occurred.
This seems to be responsible for a bunch of panics where the process
sleeps and something else finds softupdates "locked" when it shouldn't
be. This commit is unreviewed, but has been a big help here.
Previously my boxes would panic pretty much on the first fsync() that
wrote something to disk.
it is no longer sufficient to get a lock on a buffer to know
that its write has been completed. We have to first get the
lock on the buffer, then check to see if it is doing a
background write. If it is doing background write, we have
to wait for the background write to finish, then check to see
if that fullfilled our dependency, and if not to start another
write. Luckily the explanation is longer than the fix.
a vnode has not been written (which would clear certain of its
dependencies). The problems arises because fsync with MNT_NOWAIT
no longer pushes all the dirty blocks associated with a vnode. It
skips those that require rollbacks, since they will just get instantly
dirty again. Such skipped blocks are marked so that they will not be
skipped a second time (otherwise circular dependencies would never
clear). So, we fsync twice to ensure that everything will be written
at least once.
have been cleaned up by deallocte_dependencies(). Once that is done, it
is safe to post the request to free the blocks. A similar change is also
needed for the freefile case.
1) Fastpath deletions. When a file is being deleted, check to see if it
was so recently created that its inode has not yet been written to
disk. If so, the delete can proceed to immediately free the inode.
2) Background writes: No file or block allocations can be done while the
bitmap is being written to disk. To avoid these stalls, the bitmap is
copied to another buffer which is written thus leaving the original
available for futher allocations.
3) Link count tracking. Constantly track the difference in i_effnlink and
i_nlink so that inodes that have had no change other than i_effnlink
need not be written.
4) Identify buffers with rollback dependencies so that the buffer flushing
daemon can choose to skip over them.
of dirrem structure rather than the collaterally created freeblks
and freefile structures. Limit the rate of buffer dirtying by the
syncer process during periods of intense file removal.
check before the inode is unlocked while grabbing its parent directory.
Once it is unlocked, other operations may slip in that could make
the inode-is-flushed check fail. Allowing other writes to the inode
before returning from fsync does not break the semantics of fsync
since we have flushed everything that was dirty at the time of the
fsync call.
quite dangerous, since the process may hold locks at the point,
and if it is stopped in that tsleep the machine may hang. Because
the sleep is so short, the PCATCH is not required here, so it has
been removed. For the future, the FreeBSD team needs to decide
whether it is still reasonable to stop a process in tsleep, as that
may affect any other code that uses PCATCH while holding kernel locks.
Submitted by: Dmitrij Tejblum <tejblum@arc.hq.cti.ru>
Reviewed by: Kirk McKusick <mckusick@mckusick.com>
* lockstatus() and VOP_ISLOCKED() gets a new process argument and a new
return value: LK_EXCLOTHER, when the lock is held exclusively by another
process.
* The ASSERT_VOP_(UN)LOCKED family is extended to use what this gives them
* Extend the vnode_if.src format to allow more exact specification than
locked/unlocked.
This commit should not do any semantic changes unless you are using
DEBUG_VFS_LOCKS.
Discussed with: grog, mch, peter, phk
Reviewed by: peter
The same goes for CD drivers and tape drivers. In systems with mixed IDE
and SCSI, devices in the same priority class will be sorted in attach
order.
Also, the 'CCD' priority is now the 'ARRAY' priority, and a number of
drivers have been modified to use that priority.
This includes the necessary changes to all drivers, except the ATA drivers.
Soren will modify those separately.
This does not include and does not require any change in the devstat
version number, since no known userland applications use the priority
enumerations.
Reviewed by: msmith, sos, phk, jlemon, mjacob, bde
resource_list_release. This removes the dependancy on the
layout of ivars.
* Move set_resource, get_resource and delete_resource from
isa_if.m to bus_if.m.
* Simplify driver code by providing wrappers to those methods:
bus_set_resource(dev, type, rid, start, count);
bus_get_resource(dev, type, rid, startp, countp);
bus_get_resource_start(dev, type, rid);
bus_get_resource_count(dev, type, rid);
bus_delete_resource(dev, type, rid);
* Delete isa_get_rsrc and use bus_get_resource_start instead.
* Fix a stupid typo in isa_alloc_resource reported by Takahashi
Yoshihiro <nyan@FreeBSD.org>.
* Print a diagnostic message if we can't assign resources to a PnP
device.
* Change device_print_prettyname() so that it doesn't print
"(no driver assigned)-1" for anonymous devices.
have been there in the first place. A GENERIC kernel shrinks almost 1k.
Add a slightly different safetybelt under nostop for tty drivers.
Add some missing FreeBSD tags
This means that we will not have to have a bpf and a non-bpf version
of our driver modules.
This does not open any security hole, because the bpf core isn't loadable
The drivers left unchanged are the "cross platform" drivers where the respective
maintainers are urged to DTRT, whatever that may be.
Add a couple of missing FreeBSD tags.
Introduce BUF_STRATEGY(struct buf *, int flag) macro, and use it throughout.
please see comment in sys/conf.h about the flag argument.
Remove strategy argument from all the diskslice/label/bad144
implementations, it should be found from the dev_t.
Remove bogus and unused strategy1 routines.
Remove open/close arguments from dssize(). Pick them up from dev_t.
Remove unused and unfinished setgeom support from diskslice/label/bad144 code.
lockmgr locks. This commit should be functionally equivalent to the old
semantics. That is, all buffer locking is done with LK_EXCLUSIVE
requests. Changes to take advantage of LK_SHARED and LK_RECURSIVE will
be done in future commits.
