sys/sys/namecache.h

   1 /*
   2  * Copyright (c) 2003,2004 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * Copyright (c) 1989, 1993
  35  *      The Regents of the University of California.  All rights reserved.
  36  *
  37  * Redistribution and use in source and binary forms, with or without
  38  * modification, are permitted provided that the following conditions
  39  * are met:
  40  * 1. Redistributions of source code must retain the above copyright
  41  *    notice, this list of conditions and the following disclaimer.
  42  * 2. Redistributions in binary form must reproduce the above copyright
  43  *    notice, this list of conditions and the following disclaimer in the
  44  *    documentation and/or other materials provided with the distribution.
  45  * 3. All advertising materials mentioning features or use of this software
  46  *    must display the following acknowledgement:
  47  *      This product includes software developed by the University of
  48  *      California, Berkeley and its contributors.
  49  * 4. Neither the name of the University nor the names of its contributors
  50  *    may be used to endorse or promote products derived from this software
  51  *    without specific prior written permission.
  52  *
  53  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  54  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  55  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  56  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  57  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  58  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  59  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  60  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  61  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  62  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  63  * SUCH DAMAGE.
  64  *
  65  * $DragonFly: src/sys/sys/namecache.h,v 1.31 2008/05/09 17:52:18 dillon Exp $
  66  */
  67
  68 #ifndef _SYS_NAMECACHE_H_
  69 #define _SYS_NAMECACHE_H_
  70
  71 #ifndef _SYS_TYPES_H_
  72 #include <sys/types.h>
  73 #endif
  74 #ifndef _SYS_QUEUE_H_
  75 #include <sys/queue.h>
  76 #endif
  77
  78 struct vnode;
  79 struct ucred;
  80 struct proc;
  81
  82 TAILQ_HEAD(namecache_list, namecache);
  83
  84 /*
  85  * The namecache structure is used to manage the filesystem namespace.  Most
  86  * vnodes cached by the system will reference one or more associated namecache
  87  * structures.
  88  *
  89  * The namecache is disjoint, there may not always be a path to the system
  90  * root through nc_parent links.  If a namecache entry has no parent, that
  91  * entry will not be hashed and can only be 'found' via '.' or '..'.
  92  *
  93  * Because the namecache structure maintains the path through mount points,
  94  * null, and union mounts, and other VFS overlays, several namecache
  95  * structures may pass through the same vnode.  Also note that namespaces
  96  * relating to non-existant (i.e. not-yet-created) files/directories may be
  97  * locked.  Lock coherency is achieved by requiring that the particular
  98  * namecache record whos parent represents the physical directory in which
  99  * the namespace operation is to occur be the one that is locked.  In
 100  * overlay cases, the (union, nullfs) VFS, or in namei when crossing a mount
 101  * point, may have to obtain multiple namespace record locks to avoid
 102  * confusion, but only the one representing the physical directory is passed
 103  * into lower layer VOP calls.
 104  *
 105  * Many new API VOP operations do not pass vnodes.  In these cases the
 106  * operations vector is typically obtained via nc_mount->mnt_vn_use_ops.
 107  */
 108 struct namecache {
 109     LIST_ENTRY(namecache) nc_hash;      /* hash chain (nc_parent,name) */
 110     TAILQ_ENTRY(namecache) nc_entry;    /* scan via nc_parent->nc_list */
 111     TAILQ_ENTRY(namecache) nc_vnode;    /* scan via vnode->v_namecache */
 112     struct namecache_list  nc_list;     /* list of children */
 113     struct namecache *nc_parent;        /* namecache entry for parent */
 114     struct      vnode *nc_vp;           /* vnode representing name or NULL */
 115     int         nc_refs;                /* ref count prevents deletion */
 116     u_short     nc_flag;
 117     u_char      nc_nlen;                /* The length of the name, 255 max */
 118     u_char      nc_unused01;
 119     char        *nc_name;               /* Separately allocated seg name */
 120     int         nc_error;
 121     int         nc_timeout;             /* compared against ticks, or 0 */
 122     int         nc_exlocks;             /* namespace locking */
 123     struct thread *nc_locktd;           /* namespace locking */
 124     int64_t     nc_unused02;            /* filesystem modified id */
 125     long        nc_namecache_gen;       /* cmp against mnt_namecache_gen */
 126 };
 127
 128 /*
 129  * Namecache handles include a mount reference allowing topologies
 130  * to be replicated with mount overlays (nullfs mounts).
 131  */
 132 struct nchandle {
 133     struct namecache *ncp;              /* ncp in underlying filesystem */
 134     struct mount *mount;                /* mount pt (possible overlay) */
 135 };
 136
 137 /*
 138  * Flags in namecache.nc_flag (u_char)
 139  */
 140 #define NCF_LOCKED      0x0001  /* locked namespace */
 141 #define NCF_WHITEOUT    0x0002  /* negative entry corresponds to whiteout */
 142 #define NCF_UNRESOLVED  0x0004  /* invalid or unresolved entry */
 143 #define NCF_ISMOUNTPT   0x0008  /* someone may have mounted on us here */
 144 #define NCF_UNUSED10    0x0010
 145 #define NCF_HASHED      0x0020  /* namecache entry in hash table */
 146 #define NCF_LOCKREQ     0x0040
 147 #define NCF_UNUSED20    0x0080
 148 #define NCF_ISSYMLINK   0x0100  /* represents a symlink */
 149 #define NCF_ISDIR       0x0200  /* represents a directory */
 150 #define NCF_DESTROYED   0x0400  /* name association is considered destroyed */
 151 #define NCF_UNUSED800   0x0800
 152
 153 /*
 154  * cache_inval[_vp]() flags
 155  */
 156 #define CINV_DESTROY    0x0001  /* flag so cache_nlookup ignores the ncp */
 157 #define CINV_UNUSED02   0x0002
 158 #define CINV_CHILDREN   0x0004  /* recursively set children to unresolved */
 159
 160 #ifdef _KERNEL
 161
 162 struct componentname;
 163 struct nlcomponent;
 164 struct mount;
 165
 166 void    cache_lock(struct nchandle *nch);
 167 int     cache_lock_nonblock(struct nchandle *nch);
 168 void    cache_unlock(struct nchandle *nch);
 169 void    cache_setvp(struct nchandle *nch, struct vnode *vp);
 170 void    cache_settimeout(struct nchandle *nch, int nticks);
 171 void    cache_setunresolved(struct nchandle *nch);
 172 void    cache_clrmountpt(struct nchandle *nch);
 173 struct nchandle cache_nlookup(struct nchandle *nch, struct nlcomponent *nlc);
 174 void    cache_allocroot(struct nchandle *nch, struct mount *mp, struct vnode *vp);
 175 struct mount *cache_findmount(struct nchandle *nch);
 176 int     cache_inval(struct nchandle *nch, int flags);
 177 int     cache_inval_vp(struct vnode *vp, int flags);
 178 int     cache_inval_vp_nonblock(struct vnode *vp);
 179 void    vfs_cache_setroot(struct vnode *vp, struct nchandle *nch);
 180
 181 int     cache_resolve(struct nchandle *nch, struct ucred *cred);
 182 void    cache_purge(struct vnode *vp);
 183 void    cache_purgevfs (struct mount *mp);
 184 int     cache_get_nonblock(struct nchandle *nch);
 185 void    cache_cleanneg(int count);
 186 void    cache_get(struct nchandle *nch, struct nchandle *target);
 187 struct nchandle *cache_hold(struct nchandle *nch);
 188 void    cache_copy(struct nchandle *nch, struct nchandle *target);
 189 void    cache_changemount(struct nchandle *nch, struct mount *mp);
 190 void    cache_put(struct nchandle *nch);
 191 void    cache_drop(struct nchandle *nch);
 192 void    cache_zero(struct nchandle *nch);
 193 void    cache_rename(struct nchandle *fnch, struct nchandle *tnch);
 194 int     cache_vget(struct nchandle *, struct ucred *, int, struct vnode **);
 195 int     cache_vref(struct nchandle *, struct ucred *, struct vnode **);
 196 int     cache_fromdvp(struct vnode *, struct ucred *, int, struct nchandle *);
 197 int     cache_fullpath(struct proc *, struct nchandle *, char **, char **);
 198
 199 #endif
 200
 201 #endif