cvs commit: src/sys/kern vfs_subr.c

[Jeff Roberson]

On Sun, 13 Mar 2005, Jeff Roberson wrote:

> jeff        2005-03-13 11:54:28 UTC
>
>   FreeBSD src repository
>
>   Modified files:
>     sys/kern             vfs_subr.c

There is a minor problem with my vget() changes that could lead to a vnode
leak in a very rare scenario.  Basically, I forgot to drop a ref if I fail
with ENOENT in one or two cases, but this only happens if you try to lock
a vnode while it's being recycled.  I'll fix it tomorrow afternoon.  Until
then, it's really nothing to worry about.

>   Log:
>    - Remove vx_lock, vx_unlock, vx_wait, etc.
>    - Add a vn_start_write/vn_finished_write around vlrureclaim so we don't do
>      writing ops without suspending.  This could suspend the vlruproc which
>      should not be a problem under normal circumstances.
>    - Manually implement VMIGHTFREE in vlrureclaim as this was the only instance
>      where it was used.
>    - Acquire a lock before calling vgone() as it now requires it.
>    - Move the acquisition of the vnode interlock from vtryrecycle() to
>      getnewvnode() so that if it fails we don't drop and reacquire the
>      vnode_free_list_mtx.
>    - Check for a usecount or holdcount at the end of vtryrecycle() in case
>      someone grabbed a ref while we were recycling.  Abort the recycle, and
>      on the final ref drop this vnode will be placed on the head of the free
>      list.
>    - Move the redundant VOP_INACTIVE protection code into the local
>      vinactive() routine to avoid code bloat.
>    - Keep the vnode lock held across calls to vgone() in several places.
>    - vgonel() no longer uses XLOCK, instead callers must hold an exclusive
>      vnode lock.  The VI_DOOMED flag is set to allow other threads to detect
>      a vnode which is no longer valid.  This flag is set until the last
>      reference is gone, and there are no chances for a new ref.  vgonel()
>      holds this lock across the entire function, which greatly simplifies
>      logic.
>    _ Only vfree() in one place in vgone() not three.
>    - Adjust vget() to check the VI_DOOMED flag prior to waiting on the lock
>      in the LK_NOWAIT case.  In other cases, check after we have slept and
>      acquired an exlusive lock.  This will simulate the old vx_wait()
>      behavior.
>
>   Sponsored by:   Isilon Systems, Inc.
>
>   Revision  Changes    Path
>   1.590     +129 -225  src/sys/kern/vfs_subr.c
>