0fc6daa72d
null_hashget() obtains the reference on the nullfs vnode, which must be dropped. - Fix a wart which existed from the introduction of the nullfs caching, do not unlock lower vnode in the nullfs_reclaim_lowervp(). It should be innocent, but now it is also formally safe. Inform the nullfs_reclaim() about this using the NULLV_NOUNLOCK flag set on nullfs inode. - Add a callback to the upper filesystems for the lower vnode unlinking. When inactivating a nullfs vnode, check if the lower vnode was unlinked, indicated by nullfs flag NULLV_DROP or VV_NOSYNC on the lower vnode, and reclaim upper vnode if so. This allows nullfs to purge cached vnodes for the unlinked lower vnode, avoiding excessive caching. Reported by: G??ran L??wkrantz <goran.lowkrantz@ismobile.com> Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 2 weeks
95 lines
3.1 KiB
C
95 lines
3.1 KiB
C
/*-
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* Copyright (c) 1992, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software donated to Berkeley by
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* Jan-Simon Pendry.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)null.h 8.3 (Berkeley) 8/20/94
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*
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* $FreeBSD$
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*/
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#ifndef FS_NULL_H
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#define FS_NULL_H
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#define NULLM_CACHE 0x0001
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struct null_mount {
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struct mount *nullm_vfs;
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struct vnode *nullm_rootvp; /* Reference to root null_node */
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uint64_t nullm_flags;
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};
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#ifdef _KERNEL
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/*
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* A cache of vnode references
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*/
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struct null_node {
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LIST_ENTRY(null_node) null_hash; /* Hash list */
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struct vnode *null_lowervp; /* VREFed once */
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struct vnode *null_vnode; /* Back pointer */
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u_int null_flags;
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};
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#define NULLV_NOUNLOCK 0x0001
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#define NULLV_DROP 0x0002
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#define MOUNTTONULLMOUNT(mp) ((struct null_mount *)((mp)->mnt_data))
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#define VTONULL(vp) ((struct null_node *)(vp)->v_data)
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#define NULLTOV(xp) ((xp)->null_vnode)
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int nullfs_init(struct vfsconf *vfsp);
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int nullfs_uninit(struct vfsconf *vfsp);
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int null_nodeget(struct mount *mp, struct vnode *target, struct vnode **vpp);
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struct vnode *null_hashget(struct mount *mp, struct vnode *lowervp);
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void null_hashrem(struct null_node *xp);
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int null_bypass(struct vop_generic_args *ap);
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#ifdef DIAGNOSTIC
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struct vnode *null_checkvp(struct vnode *vp, char *fil, int lno);
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#define NULLVPTOLOWERVP(vp) null_checkvp((vp), __FILE__, __LINE__)
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#else
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#define NULLVPTOLOWERVP(vp) (VTONULL(vp)->null_lowervp)
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#endif
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extern struct vop_vector null_vnodeops;
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#ifdef MALLOC_DECLARE
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MALLOC_DECLARE(M_NULLFSNODE);
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#endif
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#ifdef NULLFS_DEBUG
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#define NULLFSDEBUG(format, args...) printf(format ,## args)
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#else
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#define NULLFSDEBUG(format, args...)
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#endif /* NULLFS_DEBUG */
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#endif /* _KERNEL */
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#endif
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