include/sys/fs/tmpnode.h

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #ifndef _SYS_FS_TMPNODE_H
  27 #define _SYS_FS_TMPNODE_H
  28
  29 #include <sys/t_lock.h>
  30 #include <vm/seg.h>
  31 #include <vm/seg_vn.h>
  32 #include <sys/vfs.h>
  33
  34 #ifdef  __cplusplus
  35 extern "C" {
  36 #endif
  37
  38 /*
  39  * tmpnode is the file system dependent node for tmpfs.
  40  *
  41  *      tn_rwlock protects access of the directory list at tn_dir
  42  *      as well as syncronizing read and writes to the tmpnode
  43  *
  44  *      tn_contents protects growing, shrinking, reading and writing
  45  *      the file along with tn_rwlock (see below).
  46  *
  47  *      tn_tlock protects updates to tn_mode and tn_nlink
  48  *
  49  *      tm_contents in the tmount filesystem data structure protects
  50  *      tn_forw and tn_back which are used to maintain a linked
  51  *      list of all tmpfs files associated with that file system
  52  *
  53  *      The anon array represents the secondary store for tmpfs.
  54  *      To grow or shrink the file or fill in holes requires
  55  *      manipulation of the anon array. These operations are protected
  56  *      by a combination of tn_rwlock and tn_contents. Growing or shrinking
  57  *      the array requires the write lock on tn_rwlock and tn_contents.
  58  *      Filling in a slot in the array requires the write lock on tn_contents.
  59  *      Reading the array requires the read lock on tn_contents.
  60  *
  61  *      The ordering of the locking is:
  62  *      tn_rwlock -> tn_contents -> page locks on pages in file
  63  *
  64  *      tn_tlock doesn't require any tmpnode locks
  65  */
  66
  67 struct tmpnode {
  68         struct tmpnode  *tn_back;               /* linked list of tmpnodes */
  69         struct tmpnode  *tn_forw;               /* linked list of tmpnodes */
  70         union {
  71                 struct {
  72                         struct tdirent  *un_dirlist; /* dirent list */
  73                         uint_t  un_dirents;     /* number of dirents */
  74                 } un_dirstruct;
  75                 char            *un_symlink;    /* pointer to symlink */
  76                 struct {
  77                         struct anon_hdr *un_anon; /* anon backing for file */
  78                         pgcnt_t un_size;        /* size repres. by array */
  79                 } un_anonstruct;
  80         } un_tmpnode;
  81         struct vnode    *tn_vnode;              /* vnode for this tmpnode */
  82         int             tn_gen;                 /* pseudo gen number for tfid */
  83         struct vattr    tn_attr;                /* attributes */
  84         krwlock_t       tn_contents;            /* vm side -serialize mods */
  85         krwlock_t       tn_rwlock;              /* rw,trunc size - serialize */
  86                                                 /* mods and directory updates */
  87         kmutex_t        tn_tlock;               /* time, flag, and nlink lock */
  88         struct tmpnode *tn_xattrdp;             /* ext. attribute directory */
  89         uint_t          tn_flags;               /* tmpnode specific flags */
  90 };
  91
  92 #define tn_dir          un_tmpnode.un_dirstruct.un_dirlist
  93 #define tn_dirents      un_tmpnode.un_dirstruct.un_dirents
  94 #define tn_symlink      un_tmpnode.un_symlink
  95 #define tn_anon         un_tmpnode.un_anonstruct.un_anon
  96 #define tn_asize        un_tmpnode.un_anonstruct.un_size
  97
  98 /*
  99  * tmnode flag values.
 100  */
 101 #define ISXATTR         0x1
 102
 103 /*
 104  * Attributes
 105  */
 106 #define tn_mask         tn_attr.va_mask
 107 #define tn_type         tn_attr.va_type
 108 #define tn_mode         tn_attr.va_mode
 109 #define tn_uid          tn_attr.va_uid
 110 #define tn_gid          tn_attr.va_gid
 111 #define tn_fsid         tn_attr.va_fsid
 112 #define tn_nodeid       tn_attr.va_nodeid
 113 #define tn_nlink        tn_attr.va_nlink
 114 #define tn_size         tn_attr.va_size
 115 #define tn_atime        tn_attr.va_atime
 116 #define tn_mtime        tn_attr.va_mtime
 117 #define tn_ctime        tn_attr.va_ctime
 118 #define tn_rdev         tn_attr.va_rdev
 119 #define tn_blksize      tn_attr.va_blksize
 120 #define tn_nblocks      tn_attr.va_nblocks
 121 #define tn_seq          tn_attr.va_seq
 122
 123 /*
 124  * tmpfs directories are made up of a linked list of tdirent structures
 125  * hanging off directory tmpnodes.  File names are not fixed length,
 126  * but are null terminated.
 127  */
 128 struct tdirent {
 129         struct tmpnode  *td_tmpnode;            /* tnode for this file */
 130         struct tdirent  *td_next;               /* next directory entry */
 131         struct tdirent  *td_prev;               /* prev directory entry */
 132         uint_t          td_offset;              /* "offset" of dir entry */
 133         uint_t          td_hash;                /* a hash of td_name */
 134         struct tdirent  *td_link;               /* linked via the hash table */
 135         struct tmpnode  *td_parent;             /* parent, dir we are in */
 136         char            *td_name;               /* must be null terminated */
 137                                                 /* max length is MAXNAMELEN */
 138 };
 139
 140 /*
 141  * tfid overlays the fid structure (for VFS_VGET)
 142  */
 143 struct tfid {
 144         uint16_t tfid_len;
 145         uint32_t tfid_ino;
 146         int32_t tfid_gen;
 147 };
 148
 149 #define ESAME   (-1)            /* trying to rename linked files (special) */
 150
 151 extern const struct vnodeops tmp_vnodeops;
 152
 153 #ifdef  __cplusplus
 154 }
 155 #endif
 156
 157 #endif  /* _SYS_FS_TMPNODE_H */