xref: /illumos-gate/usr/src/uts/common/sys/fs/tmpnode.h (revision d67944fb)
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_opreg.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 	ino32_t	tfid_ino;
146 	int32_t	tfid_gen;
147 };
148 
149 #define	ESAME	(-1)		/* trying to rename linked files (special) */
150 
151 extern struct vnodeops *tmp_vnodeops;
152 extern const struct fs_operation_def tmp_vnodeops_template[];
153 
154 #ifdef	__cplusplus
155 }
156 #endif
157 
158 #endif	/* _SYS_FS_TMPNODE_H */
159