- Do reference counting for 'struct mount'. Each vnode associated with a
mount takes a reference, and in turn the mount takes a reference to the
vfsops.
- Now that mounts are reference counted, replace the overcomplicated mount
locking inherited from 4.4BSD with a recursable rwlock.
shutdown). There are still problems with device access and a PR will be
filed.
- Kill checkalias(). Allow multiple vnodes to reference a single device.
- Don't play dangerous tricks with block vnodes to ensure that only one
vnode can describe a block device. Instead, prohibit concurrent opens of
block devices. As a bonus remove the unreliable code that prevents
multiple file system mounts on the same device. It's no longer needed.
- Track opens by vnode and by device. Issue cdev_close() when the last open
goes away, instead of abusing vnode::v_usecount to tell if the device is
open.
- Lock processes, credentials, filehead etc correctly.
- Acquire a read hold on sysctl_treelock if only doing a query.
- Don't wire down the output buffer. It doesn't work correctly and the code
regularly does long term sleeps with it held - it's not worth it.
- Don't hold locks other than sysctl_lock while doing copyout().
- Drop sysctl_lock while doing copyout / allocating memory in a few places.
- Don't take kernel_lock for sysctl.
- Fix a number of bugs spotted along the way
The general trend is to remove it from all kernel interfaces and
this is a start. In case the calling lwp is desired, curlwp should
be used.
quick consensus on tech-kern
- Instead of hooking the handler on the specdev of a mounted file system
hook directly on the `struct mount'.
- Rename from `vn_cow_*' to `fscow_*' and move to `kern/vfs_trans.c'. Use
`mount_*specific' instead of clobbering `struct mount' or `struct specinfo'.
- Replace the hand-made reader/writer lock with a krwlock.
- Keep `vn_cow_*' functions and mark as obsolete.
- Welcome to NetBSD 4.99.32 - `struct specinfo' changed size.
Reviewed by: Jason Thorpe <thorpej@netbsd.org>
introduce vrele2(), which allows to release vnodes the way lfs
sometimes wants it:
+ without calling inactive
+ inserting the vnode at the head of the freelist (this is a very
questionable optimization that isn't even enabled by default,
but I went along with the same semantics for now)
conjunction with LK_DRAIN. This has the same effect as LK_DRAIN
except it atomically does NOT mark the lock as drained. This
guarantees that when we got the lock, we were the last one currently
waiting for the lock.
Use LK_DRAIN|LK_RESURRECT in vclean() to make sure there are no
waiters for the lock. This should fix behaviour theoretized to be
caused by vfs_subr.c 1.289 which caused vclean() to run into
completion and free the vnode before all lock-waiters had been
processed. Should therefore fix the "simple_lock: unitialized lock"
problems seen recently.
thanks to Juergen Hannken-Illjes for some analysis of the problem
and Erik Bertelsen for testing
might be used by upper layers in the vnode stack due to exported
lock pointers. This introduces no difference to the normal case
and works around a problem where a lower layer vnode is cleaned
out before the upper layer due to forced unmount or revoke. And
for cosmetics, set a vnode's lock export to NULL when it is cleaned
out.
per discussion with Bill Stouder-Studenmund on tech-kern
to skip unnecessary flushing when layered file system vnodes are recycled.
this also prevents a deadlock with the dodgy LFS putpages routine.
fixes the non-LFS part of PR 36150.
corresponding flags.
Revert softdep_trackbufs() to its state before vn_start_write() was added.
Remove from struct mount now unneeded flags IMNT_SUSPEND* and
members mnt_writeopcountupper, mnt_writeopcountlower and mnt_leaf.
Welcome to 4.99.17
