/* * Copyright (c) 2003,2004-2019 The DragonFly Project. All rights reserved. * * This code is derived from software contributed to The DragonFly Project * by Matthew Dillon <dillon@backplane.com> * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name of The DragonFly Project nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific, prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * Copyright (c) 1989, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef _SYS_NAMECACHE_H_ #define _SYS_NAMECACHE_H_ #ifndef _SYS_TYPES_H_ #include <sys/types.h> #endif #ifndef _SYS_LOCK_H_ #include <sys/lock.h> #endif #ifndef _SYS_QUEUE_H_ #include <sys/queue.h> #endif #ifndef _SYS_SPINLOCK_H_ #include <sys/spinlock.h> #endif struct vnode; struct ucred; struct proc; TAILQ_HEAD(namecache_list, namecache); /* * The namecache structure is used to manage the filesystem namespace. Most * vnodes cached by the system will reference one or more associated namecache * structures. * * The DragonFly namecache maintains elements from active nodes to the root * in all but the NFS server case and the removed file/directory case. * NFS servers use fhtovp() and may have to regenerate the topology to * the leaf on the fly. * * Because the namecache structure maintains the path through mount points, * null, and union mounts, and other VFS overlays, several namecache * structures may pass through the same vnode. Also note that namespaces * relating to non-existant (i.e. not-yet-created) files/directories may be * locked. Lock coherency is achieved by requiring that the particular * namecache record whos parent represents the physical directory in which * the namespace operation is to occur be the one that is locked. In * overlay cases, the (union, nullfs) VFS, or in namei when crossing a mount * point, may have to obtain multiple namespace record locks to avoid * confusion, but only the one representing the physical directory is passed * into lower layer VOP calls. * * ncp locking is done using atomic ops on nc_lockstatus, including a request * flag for waiters. nc_locktd is set after locking or cleared before * the last unlock. ncp locks are reentrant. * * Many new API VOP operations do not pass vnodes. In these cases the * operations vector is typically obtained via nc_mount->mnt_vn_use_ops. * * nc_refs - * This is naturally 1, plus 1 more if resolved (either positively * or negatively), plus 1 ref for each child in ncp->nc_list, plus * thread-held and mountcache refs. * * nc_generation - * This is adjusted by 2 whenever a locked ncp's resolve state, * destroyed state, name/association, or link state changes, and * then adjusted by 2 again when the operation is complete. Thus, * if (nc_generation & 2) != 0 or (nc_generation & ~1) has changed, * an unlocked accessor should cycle a lock and retry. */ struct namecache { TAILQ_ENTRY(namecache) nc_hash; /* hash chain (nc_parent,name) */ TAILQ_ENTRY(namecache) nc_entry; /* scan via nc_parent->nc_list */ TAILQ_ENTRY(namecache) nc_vnode; /* scan via vnode->v_namecache */ struct namecache_list nc_list; /* list of children */ struct nchash_head *nc_head; struct namecache *nc_parent; /* namecache entry for parent */ struct vnode *nc_vp; /* vnode representing name or NULL */ u_short nc_flag; u_char nc_nlen; /* The length of the name, 255 max */ u_char nc_unused; char *nc_name; /* Separately allocated seg name */ int nc_error; int nc_timeout; /* compared against ticks, or 0 */ int nc_negcpu; /* which ncneg list are we on? */ struct { u_int nc_namecache_gen; /* mount generation (autoclear) */ u_int nc_generation; /* see notes above */ int nc_refs; /* ref count prevents deletion */ } __cachealign; struct { struct lock nc_lock; } __cachealign; }; /* * Namecache handles include a mount reference allowing topologies * to be replicated with mount overlays (nullfs mounts). */ struct nchandle { struct namecache *ncp; /* ncp in underlying filesystem */ struct mount *mount; /* mount pt (possible overlay) */ }; /* * Flags in namecache.nc_flag (u_short) */ #define NCF_NOTX 0x0001 /* 'x' bit not set in user, group, or world */ #define NCF_WHITEOUT 0x0002 /* negative entry corresponds to whiteout */ #define NCF_UNRESOLVED 0x0004 /* invalid or unresolved entry */ #define NCF_ISMOUNTPT 0x0008 /* someone may have mounted on us here */ #define NCF_SF_NOCACHE 0x0010 /* track swapcache chflags from attr */ #define NCF_UF_CACHE 0x0020 #define NCF_SF_PNOCACHE 0x0040 /* track from parent */ #define NCF_UF_PCACHE 0x0080 #define NCF_ISSYMLINK 0x0100 /* represents a symlink */ #define NCF_ISDIR 0x0200 /* represents a directory */ #define NCF_DESTROYED 0x0400 /* name association is considered destroyed */ #define NCF_DEFEREDZAP 0x0800 /* zap defered due to lock unavailability */ #define NCF_WXOK 0x1000 /* world-searchable (nlookup shortcut) */ #define NCF_DUMMY 0x2000 /* dummy ncp, iterations ignore it */ /* * cache_inval[_vp]() flags */ #define CINV_DESTROY 0x0001 /* flag so cache_nlookup ignores the ncp */ #define CINV_UNUSED02 0x0002 #define CINV_CHILDREN 0x0004 /* recursively set children to unresolved */ #ifdef _KERNEL struct componentname; struct nlcomponent; struct mount; void cache_clearmntcache(struct mount *mp); void cache_lock(struct nchandle *nch); void cache_lock_maybe_shared(struct nchandle *nch, int excl); void cache_lock4_tondlocked( struct nchandle *fncpd, struct nchandle *fncp, struct nchandle *tncpd, struct nchandle *tncp, struct ucred *fcred, struct ucred *tcred); int cache_lock_nonblock(struct nchandle *nch); void cache_unlock(struct nchandle *nch); int cache_lockstatus(struct nchandle *nch); void cache_setvp(struct nchandle *nch, struct vnode *vp); void cache_settimeout(struct nchandle *nch, int nticks); void cache_setunresolved(struct nchandle *nch); void cache_clrmountpt(struct nchandle *nch); struct nchandle cache_nlookup(struct nchandle *nch, struct nlcomponent *nlc); struct nchandle cache_nlookup_nonblock(struct nchandle *nch, struct nlcomponent *nlc); struct nchandle cache_nlookup_nonlocked(struct nchandle *nch, struct nlcomponent *nlc); int cache_nlookup_maybe_shared(struct nchandle *nch, struct nlcomponent *nlc, int excl, struct nchandle *nchres); void cache_allocroot(struct nchandle *nch, struct mount *mp, struct vnode *vp); struct mount *cache_findmount(struct nchandle *nch); void cache_dropmount(struct mount *mp); void cache_ismounting(struct mount *mp); void cache_unmounting(struct mount *mp); int cache_inval(struct nchandle *nch, int flags); int cache_inval_vp(struct vnode *vp, int flags); int cache_inval_vp_nonblock(struct vnode *vp); void cache_inval_vp_quick(struct vnode *vp); void cache_inval_wxok(struct vnode *vp); void vfs_cache_setroot(struct vnode *vp, struct nchandle *nch); int cache_resolve(struct nchandle *nch, u_int *genp, struct ucred *cred); int cache_resolve_dvp(struct nchandle *nch, struct ucred *cred, struct vnode **dvpp); void cache_purge(struct vnode *vp); void cache_purgevfs (struct mount *mp); void cache_hysteresis(int critpath); void cache_get(struct nchandle *nch, struct nchandle *target); int cache_get_nonblock(struct nchandle *nch, int elmno, struct nchandle *target); void cache_get_maybe_shared(struct nchandle *nch, struct nchandle *target, int excl); struct nchandle *cache_hold(struct nchandle *nch); void cache_copy(struct nchandle *nch, struct nchandle *target); void cache_changemount(struct nchandle *nch, struct mount *mp); void cache_put(struct nchandle *nch); void cache_drop(struct nchandle *nch); void cache_drop_and_cache(struct nchandle *nch, int elmno); void cache_zero(struct nchandle *nch); void cache_rename(struct nchandle *fnch, struct nchandle *tnch); void cache_unlink(struct nchandle *nch); int cache_isopen(struct nchandle *nch); int cache_vget(struct nchandle *, struct ucred *, int, struct vnode **); int cache_vref(struct nchandle *, struct ucred *, struct vnode **); int cache_fromdvp(struct vnode *, struct ucred *, int, struct nchandle *); int cache_fullpath(struct proc *, struct nchandle *, struct nchandle *, char **, char **, int); void vfscache_rollup_cpu(struct globaldata *gd); struct vnode *cache_dvpref(struct namecache *ncp); #endif #endif
