include/sys/fs/tmp.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 2007 Sun Microsystems, Inc.
  23  * All rights reserved.  Use is subject to license terms.
  24  */
  25 /*
  26  * Copyright 2015 Joyent, Inc.
  27  */
  28
  29 #ifndef _SYS_FS_TMP_H
  30 #define _SYS_FS_TMP_H
  31
  32 #ifdef  __cplusplus
  33 extern "C" {
  34 #endif
  35
  36 /*
  37  * tmpfs per-mount data structure.
  38  *
  39  * All fields are protected by tm_contents.
  40  * File renames on a particular file system are protected tm_renamelck.
  41  */
  42 struct tmount {
  43         struct vfs      *tm_vfsp;       /* filesystem's vfs struct */
  44         struct tmpnode  *tm_rootnode;   /* root tmpnode */
  45         char            *tm_mntpath;    /* name of tmpfs mount point */
  46         ulong_t         tm_anonmax;     /* file system max anon reservation */
  47         pgcnt_t         tm_anonmem;     /* pages of reserved anon memory */
  48         dev_t           tm_dev;         /* unique dev # of mounted `device' */
  49         uint_t          tm_gen;         /* pseudo generation number for files */
  50         kmutex_t        tm_contents;    /* lock for tmount structure */
  51         kmutex_t        tm_renamelck;   /* rename lock for this mount */
  52 };
  53
  54 /*
  55  * File system independent to tmpfs conversion macros
  56  */
  57 #define VFSTOTM(vfsp)           ((struct tmount *)(vfsp)->vfs_data)
  58 #define VTOTM(vp)               ((struct tmount *)(vp)->v_vfsp->vfs_data)
  59 #define VTOTN(vp)               ((struct tmpnode *)(vp)->v_data)
  60 #define TNTOV(tp)               ((tp)->tn_vnode)
  61 #define tmpnode_hold(tp)        VN_HOLD(TNTOV(tp))
  62 #define tmpnode_rele(tp)        VN_RELE(TNTOV(tp))
  63
  64 /*
  65  * enums
  66  */
  67 enum de_op      { DE_CREATE, DE_MKDIR, DE_LINK, DE_RENAME }; /* direnter ops */
  68 enum dr_op      { DR_REMOVE, DR_RMDIR, DR_RENAME };     /* dirremove ops */
  69
  70 /*
  71  * tmpfs_minfree is the amount (in pages) of anonymous memory that tmpfs
  72  * leaves free for the rest of the system.  E.g. in a system with 32MB of
  73  * configured swap space, if 16MB were reserved (leaving 16MB free),
  74  * tmpfs could allocate up to 16MB - tmpfs_minfree.  The default value
  75  * for tmpfs_minfree is btopr(TMPMINFREE) but it can cautiously patched
  76  * to a different number of pages.
  77  * NB: If tmpfs allocates too much swap space, other processes will be
  78  * unable to execute.
  79  */
  80 #define TMPMINFREE      2 * 1024 * 1024 /* 2 Megabytes */
  81
  82 extern size_t   tmpfs_minfree;          /* Anonymous memory in pages */
  83
  84 /*
  85  * tmpfs can allocate only a certain percentage of kernel memory,
  86  * which is used for tmpnodes, directories, file names, etc.
  87  * This is statically set as TMPMAXFRACKMEM of physical memory.
  88  * The actual number of allocatable bytes can be patched in tmpfs_maxkmem.
  89  */
  90 #define TMPMAXFRACKMEM  25      /* 1/25 of physical memory */
  91
  92 extern size_t   tmp_kmemspace;
  93 extern size_t   tmpfs_maxkmem;  /* Allocatable kernel memory in bytes */
  94
  95 extern  void    tmpnode_init(struct tmount *, struct tmpnode *,
  96         struct vattr *, struct cred *);
  97 extern  int     tmpnode_trunc(struct tmount *, struct tmpnode *, ulong_t);
  98 extern  void    tmpnode_growmap(struct tmpnode *, ulong_t);
  99 extern  int     tdirlookup(struct tmpnode *, char *, struct tmpnode **,
 100     struct cred *);
 101 extern  int     tdirdelete(struct tmpnode *, struct tmpnode *, char *,
 102         enum dr_op, struct cred *);
 103 extern  void    tdirinit(struct tmpnode *, struct tmpnode *);
 104 extern  void    tdirtrunc(struct tmpnode *);
 105 extern  void    *tmp_memalloc(size_t, int);
 106 extern  void    tmp_memfree(void *, size_t);
 107 extern  int     tmp_resv(struct tmount *, struct tmpnode *, size_t, int);
 108 extern  int     tmp_taccess(void *, int, struct cred *);
 109 extern  int     tmp_sticky_remove_access(struct tmpnode *, struct tmpnode *,
 110         struct cred *);
 111 extern  int     tmp_convnum(char *, pgcnt_t *);
 112 extern  int     tmp_convmode(char *, mode_t *);
 113 extern  int     tdirenter(struct tmount *, struct tmpnode *, char *,
 114         enum de_op, struct tmpnode *, struct tmpnode *, struct vattr *,
 115         struct tmpnode **, struct cred *, caller_context_t *);
 116
 117 #define TMP_MUSTHAVE    0x01
 118
 119 #ifdef  __cplusplus
 120 }
 121 #endif
 122
 123 #endif  /* _SYS_FS_TMP_H */