xref: /illumos-gate/usr/src/uts/common/sys/fs/tmp.h (revision 401bc9af09d3e2bcb61df16867750651ccb30004)
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 */
124