1/*	$NetBSD: tmpfs.h,v 1.56 2020/05/17 19:39:15 ad Exp $	*/
2
3/*
4 * Copyright (c) 2005, 2006, 2007, 2020 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Julio M. Merino Vidal, developed as part of Google's Summer of Code
9 * 2005 program.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 */
32
33#ifndef _FS_TMPFS_TMPFS_H_
34#define _FS_TMPFS_TMPFS_H_
35
36#if !defined(_KERNEL) && !defined(_KMEMUSER)
37#error "not supposed to be exposed to userland"
38#endif
39
40#include <sys/dirent.h>
41#include <sys/mount.h>
42#include <sys/pool.h>
43#include <sys/queue.h>
44#include <sys/vnode.h>
45
46/*
47 * Internal representation of a tmpfs directory entry.
48 *
49 * All fields are protected by vnode lock.
50 */
51typedef struct tmpfs_dirent {
52	TAILQ_ENTRY(tmpfs_dirent)	td_entries;
53
54	/* Pointer to the inode this entry refers to. */
55	struct tmpfs_node *		td_node;
56
57	/* Sequence number, see tmpfs_dir_getseq(). */
58	uint32_t			td_seq;
59
60	/* Name and its length. */
61	char *				td_name;
62	uint16_t			td_namelen;
63} tmpfs_dirent_t;
64
65TAILQ_HEAD(tmpfs_dir, tmpfs_dirent);
66
67/*
68 * Internal representation of a tmpfs file system node -- inode.
69 *
70 * This structure is split in two parts: one holds attributes common
71 * to all file types and the other holds data that is only applicable to
72 * a particular type.
73 *
74 * All fields are protected by vnode lock.  The vnode association itself
75 * is protected by vcache.
76 */
77typedef struct tmpfs_node {
78	LIST_ENTRY(tmpfs_node)	tn_entries;
79
80	/*
81	 * Each inode has a corresponding vnode.  It is a bi-directional
82	 * association.  Whenever vnode is allocated, its v_data field is
83	 * set to the inode it reference, and tmpfs_node_t::tn_vnode is
84	 * set to point to the said vnode.
85	 *
86	 * Further attempts to allocate a vnode for this same node will
87	 * result in returning a new reference to the value stored in
88	 * tn_vnode.  It may be NULL when the node is unused (that is,
89	 * no vnode has been allocated or it has been reclaimed).
90	 */
91	vnode_t *		tn_vnode;
92
93	/* Prevent node from being reclaimed. */
94	uint32_t		tn_holdcount;
95
96	/* Directory entry.  Only a hint, since hard link can have multiple. */
97	tmpfs_dirent_t *	tn_dirent_hint;
98
99	/* The inode type: VBLK, VCHR, VDIR, VFIFO, VLNK, VREG or VSOCK. */
100	enum vtype		tn_type;
101
102	/* Inode identifier and generation number. */
103	ino_t			tn_id;
104	uint32_t		tn_gen;
105
106	/* The inode size. */
107	off_t			tn_size;
108
109	/* Generic node attributes. */
110	uid_t			tn_uid;
111	gid_t			tn_gid;
112	mode_t			tn_mode;
113	int			tn_flags;
114	nlink_t			tn_links;
115	unsigned		tn_tflags;
116	struct timespec		tn_atime;
117	struct timespec		tn_mtime;
118	struct timespec		tn_ctime;
119	struct timespec		tn_birthtime;
120	kmutex_t		tn_timelock;
121
122	/* Head of byte-level lock list (used by tmpfs_advlock). */
123	struct lockf *		tn_lockf;
124
125	union {
126		/* Type case: VBLK or VCHR. */
127		struct {
128			dev_t			tn_rdev;
129		} tn_dev;
130
131		/* Type case: VDIR. */
132		struct {
133			/* Parent directory (root inode points to itself). */
134			struct tmpfs_node *	tn_parent;
135
136			/* List of directory entries. */
137			struct tmpfs_dir	tn_dir;
138
139			/* Last given sequence number and their arena. */
140			uint32_t		tn_next_seq;
141			void *			tn_seq_arena;
142
143			/*
144			 * Pointer of the last directory entry returned
145			 * by the readdir(3) operation.
146			 */
147			struct tmpfs_dirent *	tn_readdir_lastp;
148		} tn_dir;
149
150		/* Type case: VLNK. */
151		struct tn_lnk {
152			/* The link's target. */
153			char *			tn_link;
154		} tn_lnk;
155
156		/* Type case: VREG. */
157		struct tn_reg {
158			/* Underlying UVM object to store contents. */
159			struct uvm_object *	tn_aobj;
160			size_t			tn_aobj_pages;
161		} tn_reg;
162	} tn_spec;
163} tmpfs_node_t;
164
165#if defined(_KERNEL)
166
167VFS_PROTOS(tmpfs);
168
169LIST_HEAD(tmpfs_node_list, tmpfs_node);
170
171#define	TMPFS_MAXNAMLEN		255
172/* Validate maximum td_namelen length. */
173CTASSERT(TMPFS_MAXNAMLEN < UINT16_MAX);
174
175/*
176 * Reserved values for the virtual entries (the first must be 0) and EOF.
177 * The start/end of the incremental range, see tmpfs_dir_getseq().
178 */
179#define	TMPFS_DIRSEQ_DOT	0
180#define	TMPFS_DIRSEQ_DOTDOT	1
181#define	TMPFS_DIRSEQ_EOF	2
182
183#define	TMPFS_DIRSEQ_START	3		/* inclusive */
184#define	TMPFS_DIRSEQ_END	(1U << 30)	/* exclusive */
185
186/* Mark to indicate that the number is not set. */
187#define	TMPFS_DIRSEQ_NONE	(1U << 31)
188
189/* Flags: time update requests. */
190#define	TMPFS_UPDATE_ATIME	0x01
191#define	TMPFS_UPDATE_MTIME	0x02
192#define	TMPFS_UPDATE_CTIME	0x04
193
194/*
195 * Bits indicating whiteout use for the directory.
196 * We abuse tmpfs_node_t::tn_gen for that.
197 */
198#define	TMPFS_WHITEOUT_BIT	(1U << 31)
199#define	TMPFS_NODE_GEN_MASK	(TMPFS_WHITEOUT_BIT - 1)
200
201#define	TMPFS_NODE_GEN(node) \
202    ((node)->tn_gen & TMPFS_NODE_GEN_MASK)
203
204/* White-out inode indicator. */
205#define	TMPFS_NODE_WHITEOUT	((tmpfs_node_t *)-1)
206
207/*
208 * Bit indicating this node must be reclaimed when holdcount reaches zero.
209 * Ored into tmpfs_node_t::tn_holdcount.
210 */
211#define TMPFS_NODE_RECLAIMED		(1U << 30)
212
213/*
214 * Internal representation of a tmpfs mount point.
215 */
216typedef struct tmpfs_mount {
217	/* Limit and number of bytes in use by the file system. */
218	uint64_t		tm_mem_limit;
219	uint64_t		tm_bytes_used;
220	kmutex_t		tm_acc_lock;
221
222	/* Pointer to the root inode. */
223	tmpfs_node_t *		tm_root;
224
225	/* Maximum number of possible nodes for this file system. */
226	unsigned int		tm_nodes_max;
227
228	/* Number of nodes currently allocated. */
229	unsigned int		tm_nodes_cnt;
230
231	/* List of inodes and the lock protecting it. */
232	kmutex_t		tm_lock;
233	struct tmpfs_node_list	tm_nodes;
234} tmpfs_mount_t;
235
236/*
237 * This structure maps a file identifier to a tmpfs node.  Used by the
238 * NFS code.
239 */
240typedef struct tmpfs_fid {
241	uint16_t		tf_len;
242	uint16_t		tf_pad;
243	uint32_t		tf_gen;
244	ino_t			tf_id;
245} tmpfs_fid_t;
246
247/*
248 * Prototypes for tmpfs_subr.c.
249 */
250
251void		tmpfs_free_node(tmpfs_mount_t *, tmpfs_node_t *);
252
253int		tmpfs_construct_node(vnode_t *, vnode_t **, struct vattr *,
254		    struct componentname *, char *);
255
256int		tmpfs_alloc_dirent(tmpfs_mount_t *, const char *, uint16_t,
257		    tmpfs_dirent_t **);
258void		tmpfs_free_dirent(tmpfs_mount_t *, tmpfs_dirent_t *);
259void		tmpfs_dir_attach(tmpfs_node_t *, tmpfs_dirent_t *, tmpfs_node_t *);
260void		tmpfs_dir_detach(tmpfs_node_t *, tmpfs_dirent_t *);
261
262tmpfs_dirent_t *tmpfs_dir_lookup(tmpfs_node_t *, struct componentname *);
263tmpfs_dirent_t *tmpfs_dir_cached(tmpfs_node_t *);
264
265uint32_t	tmpfs_dir_getseq(tmpfs_node_t *, tmpfs_dirent_t *);
266tmpfs_dirent_t *tmpfs_dir_lookupbyseq(tmpfs_node_t *, off_t);
267int		tmpfs_dir_getdents(tmpfs_node_t *, struct uio *, off_t *);
268
269int		tmpfs_reg_resize(vnode_t *, off_t);
270
271int		tmpfs_chflags(vnode_t *, int, kauth_cred_t, lwp_t *);
272int		tmpfs_chmod(vnode_t *, mode_t, kauth_cred_t, lwp_t *);
273int		tmpfs_chown(vnode_t *, uid_t, gid_t, kauth_cred_t, lwp_t *);
274int		tmpfs_chsize(vnode_t *, u_quad_t, kauth_cred_t, lwp_t *);
275int		tmpfs_chtimes(vnode_t *, const struct timespec *,
276		    const struct timespec *, const struct timespec *, int,
277		    kauth_cred_t, lwp_t *);
278void		tmpfs_update(vnode_t *, unsigned);
279void		tmpfs_update_locked(vnode_t *, unsigned);
280void		tmpfs_update_lazily(vnode_t *, unsigned);
281
282/*
283 * Prototypes for tmpfs_mem.c.
284 */
285
286void		tmpfs_mntmem_init(tmpfs_mount_t *, uint64_t);
287void		tmpfs_mntmem_destroy(tmpfs_mount_t *);
288int		tmpfs_mntmem_set(tmpfs_mount_t *, uint64_t);
289
290size_t		tmpfs_mem_info(bool);
291uint64_t	tmpfs_bytes_max(tmpfs_mount_t *);
292size_t		tmpfs_pages_avail(tmpfs_mount_t *);
293bool		tmpfs_mem_incr(tmpfs_mount_t *, size_t);
294void		tmpfs_mem_decr(tmpfs_mount_t *, size_t);
295
296tmpfs_dirent_t *tmpfs_dirent_get(tmpfs_mount_t *);
297void		tmpfs_dirent_put(tmpfs_mount_t *, tmpfs_dirent_t *);
298
299tmpfs_node_t *	tmpfs_node_get(tmpfs_mount_t *);
300void		tmpfs_node_put(tmpfs_mount_t *, tmpfs_node_t *);
301
302char *		tmpfs_strname_alloc(tmpfs_mount_t *, size_t);
303void		tmpfs_strname_free(tmpfs_mount_t *, char *, size_t);
304bool		tmpfs_strname_neqlen(struct componentname *, struct componentname *);
305
306/*
307 * Ensures that the node pointed by 'node' is a directory and that its
308 * contents are consistent with respect to directories.
309 */
310#define	TMPFS_VALIDATE_DIR(node) \
311    KASSERT((node)->tn_vnode == NULL || VOP_ISLOCKED((node)->tn_vnode)); \
312    KASSERT((node)->tn_type == VDIR); \
313    KASSERT((node)->tn_size % sizeof(tmpfs_dirent_t) == 0);
314
315/*
316 * Routines to convert VFS structures to tmpfs internal ones.
317 */
318
319static __inline tmpfs_mount_t *
320VFS_TO_TMPFS(struct mount *mp)
321{
322	tmpfs_mount_t *tmp = mp->mnt_data;
323
324	KASSERT(tmp != NULL);
325	return tmp;
326}
327
328static __inline tmpfs_node_t *
329VP_TO_TMPFS_DIR(vnode_t *vp)
330{
331	tmpfs_node_t *node = vp->v_data;
332
333	KASSERT(node != NULL);
334	TMPFS_VALIDATE_DIR(node);
335	return node;
336}
337
338#endif /* defined(_KERNEL) */
339
340static __inline tmpfs_node_t *
341VP_TO_TMPFS_NODE(vnode_t *vp)
342{
343	tmpfs_node_t *node = vp->v_data;
344#ifdef KASSERT
345	KASSERT(node != NULL);
346#endif
347	return node;
348}
349
350#endif /* _FS_TMPFS_TMPFS_H_ */
351