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 2016 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 size_t tm_anonmax; /* file system max anon reservation */
47 size_t tm_anonmem; /* bytes of reserved anon memory */
48 /* and allocated kmem for the fs */
49 size_t tm_allocmem; /* bytes alloced from tmp_kmem_ funcs */
50 dev_t tm_dev; /* unique dev # of mounted `device' */
51 uint_t tm_gen; /* pseudo generation number for files */
52 kmutex_t tm_contents; /* lock for tmount structure */
53 kmutex_t tm_renamelck; /* rename lock for this mount */
54 };
55
56 /*
57 * File system independent to tmpfs conversion macros
58 */
59 #define VFSTOTM(vfsp) ((struct tmount *)(vfsp)->vfs_data)
60 #define VTOTM(vp) ((struct tmount *)(vp)->v_vfsp->vfs_data)
61 #define VTOTN(vp) ((struct tmpnode *)(vp)->v_data)
62 #define TNTOV(tp) ((tp)->tn_vnode)
63 #define TNTOTM(tp) (VTOTM(TNTOV(tp)))
64 #define tmpnode_hold(tp) VN_HOLD(TNTOV(tp))
65 #define tmpnode_rele(tp) VN_RELE(TNTOV(tp))
66
67 /*
68 * enums
69 */
70 enum de_op { DE_CREATE, DE_MKDIR, DE_LINK, DE_RENAME }; /* direnter ops */
71 enum dr_op { DR_REMOVE, DR_RMDIR, DR_RENAME }; /* dirremove ops */
72
73 /*
74 * tmpfs_minfree is the amount (in pages) of anonymous memory that tmpfs
75 * leaves free for the rest of the system. In antiquity, this number could be
76 * relevant on a system-wide basis, as physical DRAM was routinely exhausted;
77 * however, in more modern times, the relative growth of DRAM with respect to
78 * application footprint means that this number is only likely to become
79 * factor in a virtualized OS environment (e.g., a zone) -- and even then only
80 * when DRAM and swap have both been capped low to allow for maximum tenancy.
81 * TMPMINFREE -- the value from which tmpfs_minfree is derived -- should
82 * therefore be configured to a value that is roughly the smallest practical
83 * value for memory + swap minus the largest reasonable size for tmpfs in such
84 * a configuration. As of this writing, the smallest practical memory + swap
85 * configuration is 128MB, and it seems reasonable to allow tmpfs to consume
86 * no more than seven-eighths of this, yielding a TMPMINFREE of 16MB. Care
87 * should be exercised in changing this: tuning this value too high will
88 * result in spurious ENOSPC errors in tmpfs in small zones (a problem that
89 * can induce cascading failure surprisingly often); tuning this value too low
90 * will result in tmpfs consumption alone to alone induce application-level
91 * memory allocation failure.
92 */
93 #define TMPMINFREE 16 * 1024 * 1024 /* 16 Megabytes */
94
95 extern size_t tmpfs_minfree; /* Anonymous memory in pages */
96
97 extern void tmpnode_init(struct tmount *, struct tmpnode *,
98 struct vattr *, struct cred *);
99 extern void tmpnode_cleanup(struct tmpnode *tp);
100 extern int tmpnode_trunc(struct tmount *, struct tmpnode *, ulong_t);
101 extern void tmpnode_growmap(struct tmpnode *, ulong_t);
102 extern int tdirlookup(struct tmpnode *, char *, struct tmpnode **,
103 struct cred *);
104 extern int tdirdelete(struct tmpnode *, struct tmpnode *, char *,
105 enum dr_op, struct cred *);
106 extern int tdirinit(struct tmpnode *, struct tmpnode *);
107 extern void tdirtrunc(struct tmpnode *);
108 extern int tmp_resv(struct tmount *, struct tmpnode *, size_t, int);
109 extern int tmp_taccess(void *, int, struct cred *);
110 extern int tmp_sticky_remove_access(struct tmpnode *, struct tmpnode *,
111 struct cred *);
112 extern int tmp_convnum(char *, size_t *);
113 extern int tmp_convmode(char *, mode_t *);
114 extern int tdirenter(struct tmount *, struct tmpnode *, char *,
115 enum de_op, struct tmpnode *, struct tmpnode *, struct vattr *,
116 struct tmpnode **, struct cred *, caller_context_t *);
117
118 extern void *tmp_kmem_zalloc(struct tmount *, size_t, int);
119 extern void tmp_kmem_free(struct tmount *, void *, size_t);
120
121 #define TMP_MUSTHAVE 0x01
122
123 #ifdef __cplusplus
124 }
125 #endif
126
127 #endif /* _SYS_FS_TMP_H */