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      1 /*	$NetBSD: tmpfs.h,v 1.51 2015/07/06 10:05:50 hannken Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2005, 2006, 2007 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  */
     51 typedef 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 
     65 TAILQ_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  */
     77 typedef 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 	struct timespec		tn_atime;
    116 	struct timespec		tn_mtime;
    117 	struct timespec		tn_ctime;
    118 	struct timespec		tn_birthtime;
    119 
    120 	/* Head of byte-level lock list (used by tmpfs_advlock). */
    121 	struct lockf *		tn_lockf;
    122 
    123 	union {
    124 		/* Type case: VBLK or VCHR. */
    125 		struct {
    126 			dev_t			tn_rdev;
    127 		} tn_dev;
    128 
    129 		/* Type case: VDIR. */
    130 		struct {
    131 			/* Parent directory (root inode points to itself). */
    132 			struct tmpfs_node *	tn_parent;
    133 
    134 			/* List of directory entries. */
    135 			struct tmpfs_dir	tn_dir;
    136 
    137 			/* Last given sequence number and their arena. */
    138 			uint32_t		tn_next_seq;
    139 			void *			tn_seq_arena;
    140 
    141 			/*
    142 			 * Pointer of the last directory entry returned
    143 			 * by the readdir(3) operation.
    144 			 */
    145 			struct tmpfs_dirent *	tn_readdir_lastp;
    146 		} tn_dir;
    147 
    148 		/* Type case: VLNK. */
    149 		struct tn_lnk {
    150 			/* The link's target. */
    151 			char *			tn_link;
    152 		} tn_lnk;
    153 
    154 		/* Type case: VREG. */
    155 		struct tn_reg {
    156 			/* Underlying UVM object to store contents. */
    157 			struct uvm_object *	tn_aobj;
    158 			size_t			tn_aobj_pages;
    159 		} tn_reg;
    160 	} tn_spec;
    161 } tmpfs_node_t;
    162 
    163 #if defined(_KERNEL)
    164 
    165 VFS_PROTOS(tmpfs);
    166 
    167 LIST_HEAD(tmpfs_node_list, tmpfs_node);
    168 
    169 #define	TMPFS_MAXNAMLEN		255
    170 /* Validate maximum td_namelen length. */
    171 CTASSERT(TMPFS_MAXNAMLEN < UINT16_MAX);
    172 
    173 /*
    174  * Reserved values for the virtual entries (the first must be 0) and EOF.
    175  * The start/end of the incremental range, see tmpfs_dir_getseq().
    176  */
    177 #define	TMPFS_DIRSEQ_DOT	0
    178 #define	TMPFS_DIRSEQ_DOTDOT	1
    179 #define	TMPFS_DIRSEQ_EOF	2
    180 
    181 #define	TMPFS_DIRSEQ_START	3		/* inclusive */
    182 #define	TMPFS_DIRSEQ_END	(1U << 30)	/* exclusive */
    183 
    184 /* Mark to indicate that the number is not set. */
    185 #define	TMPFS_DIRSEQ_NONE	(1U << 31)
    186 
    187 /* Flags: time update requests. */
    188 #define	TMPFS_UPDATE_ATIME	0x01
    189 #define	TMPFS_UPDATE_MTIME	0x02
    190 #define	TMPFS_UPDATE_CTIME	0x04
    191 
    192 /*
    193  * Bits indicating whiteout use for the directory.
    194  * We abuse tmpfs_node_t::tn_gen for that.
    195  */
    196 #define	TMPFS_WHITEOUT_BIT	(1U << 31)
    197 #define	TMPFS_NODE_GEN_MASK	(TMPFS_WHITEOUT_BIT - 1)
    198 
    199 #define	TMPFS_NODE_GEN(node) \
    200     ((node)->tn_gen & TMPFS_NODE_GEN_MASK)
    201 
    202 /* White-out inode indicator. */
    203 #define	TMPFS_NODE_WHITEOUT	((tmpfs_node_t *)-1)
    204 
    205 /*
    206  * Bit indicating this node must be reclaimed when holdcount reaches zero.
    207  * Ored into tmpfs_node_t::tn_holdcount.
    208  */
    209 #define TMPFS_NODE_RECLAIMED		(1U << 30)
    210 
    211 /*
    212  * Internal representation of a tmpfs mount point.
    213  */
    214 typedef struct tmpfs_mount {
    215 	/* Limit and number of bytes in use by the file system. */
    216 	uint64_t		tm_mem_limit;
    217 	uint64_t		tm_bytes_used;
    218 	kmutex_t		tm_acc_lock;
    219 
    220 	/* Pointer to the root inode. */
    221 	tmpfs_node_t *		tm_root;
    222 
    223 	/* Maximum number of possible nodes for this file system. */
    224 	unsigned int		tm_nodes_max;
    225 
    226 	/* Number of nodes currently allocated. */
    227 	unsigned int		tm_nodes_cnt;
    228 
    229 	/* List of inodes and the lock protecting it. */
    230 	kmutex_t		tm_lock;
    231 	struct tmpfs_node_list	tm_nodes;
    232 } tmpfs_mount_t;
    233 
    234 /*
    235  * This structure maps a file identifier to a tmpfs node.  Used by the
    236  * NFS code.
    237  */
    238 typedef struct tmpfs_fid {
    239 	uint16_t		tf_len;
    240 	uint16_t		tf_pad;
    241 	uint32_t		tf_gen;
    242 	ino_t			tf_id;
    243 } tmpfs_fid_t;
    244 
    245 /*
    246  * Prototypes for tmpfs_subr.c.
    247  */
    248 
    249 void		tmpfs_free_node(tmpfs_mount_t *, tmpfs_node_t *);
    250 
    251 int		tmpfs_construct_node(vnode_t *, vnode_t **, struct vattr *,
    252 		    struct componentname *, char *);
    253 
    254 int		tmpfs_alloc_dirent(tmpfs_mount_t *, const char *, uint16_t,
    255 		    tmpfs_dirent_t **);
    256 void		tmpfs_free_dirent(tmpfs_mount_t *, tmpfs_dirent_t *);
    257 void		tmpfs_dir_attach(tmpfs_node_t *, tmpfs_dirent_t *, tmpfs_node_t *);
    258 void		tmpfs_dir_detach(tmpfs_node_t *, tmpfs_dirent_t *);
    259 
    260 tmpfs_dirent_t *tmpfs_dir_lookup(tmpfs_node_t *, struct componentname *);
    261 tmpfs_dirent_t *tmpfs_dir_cached(tmpfs_node_t *);
    262 
    263 uint32_t	tmpfs_dir_getseq(tmpfs_node_t *, tmpfs_dirent_t *);
    264 tmpfs_dirent_t *tmpfs_dir_lookupbyseq(tmpfs_node_t *, off_t);
    265 int		tmpfs_dir_getdents(tmpfs_node_t *, struct uio *, off_t *);
    266 
    267 int		tmpfs_reg_resize(vnode_t *, off_t);
    268 
    269 int		tmpfs_chflags(vnode_t *, int, kauth_cred_t, lwp_t *);
    270 int		tmpfs_chmod(vnode_t *, mode_t, kauth_cred_t, lwp_t *);
    271 int		tmpfs_chown(vnode_t *, uid_t, gid_t, kauth_cred_t, lwp_t *);
    272 int		tmpfs_chsize(vnode_t *, u_quad_t, kauth_cred_t, lwp_t *);
    273 int		tmpfs_chtimes(vnode_t *, const struct timespec *,
    274 		    const struct timespec *, const struct timespec *, int,
    275 		    kauth_cred_t, lwp_t *);
    276 void		tmpfs_update(vnode_t *, unsigned);
    277 
    278 /*
    279  * Prototypes for tmpfs_mem.c.
    280  */
    281 
    282 void		tmpfs_mntmem_init(tmpfs_mount_t *, uint64_t);
    283 void		tmpfs_mntmem_destroy(tmpfs_mount_t *);
    284 int		tmpfs_mntmem_set(tmpfs_mount_t *, uint64_t);
    285 
    286 size_t		tmpfs_mem_info(bool);
    287 uint64_t	tmpfs_bytes_max(tmpfs_mount_t *);
    288 size_t		tmpfs_pages_avail(tmpfs_mount_t *);
    289 bool		tmpfs_mem_incr(tmpfs_mount_t *, size_t);
    290 void		tmpfs_mem_decr(tmpfs_mount_t *, size_t);
    291 
    292 tmpfs_dirent_t *tmpfs_dirent_get(tmpfs_mount_t *);
    293 void		tmpfs_dirent_put(tmpfs_mount_t *, tmpfs_dirent_t *);
    294 
    295 tmpfs_node_t *	tmpfs_node_get(tmpfs_mount_t *);
    296 void		tmpfs_node_put(tmpfs_mount_t *, tmpfs_node_t *);
    297 
    298 char *		tmpfs_strname_alloc(tmpfs_mount_t *, size_t);
    299 void		tmpfs_strname_free(tmpfs_mount_t *, char *, size_t);
    300 bool		tmpfs_strname_neqlen(struct componentname *, struct componentname *);
    301 
    302 /*
    303  * Ensures that the node pointed by 'node' is a directory and that its
    304  * contents are consistent with respect to directories.
    305  */
    306 #define	TMPFS_VALIDATE_DIR(node) \
    307     KASSERT((node)->tn_vnode == NULL || VOP_ISLOCKED((node)->tn_vnode)); \
    308     KASSERT((node)->tn_type == VDIR); \
    309     KASSERT((node)->tn_size % sizeof(tmpfs_dirent_t) == 0);
    310 
    311 /*
    312  * Routines to convert VFS structures to tmpfs internal ones.
    313  */
    314 
    315 static inline tmpfs_mount_t *
    316 VFS_TO_TMPFS(struct mount *mp)
    317 {
    318 	tmpfs_mount_t *tmp = mp->mnt_data;
    319 
    320 	KASSERT(tmp != NULL);
    321 	return tmp;
    322 }
    323 
    324 static inline tmpfs_node_t *
    325 VP_TO_TMPFS_DIR(vnode_t *vp)
    326 {
    327 	tmpfs_node_t *node = vp->v_data;
    328 
    329 	KASSERT(node != NULL);
    330 	TMPFS_VALIDATE_DIR(node);
    331 	return node;
    332 }
    333 
    334 #endif /* defined(_KERNEL) */
    335 
    336 static __inline tmpfs_node_t *
    337 VP_TO_TMPFS_NODE(vnode_t *vp)
    338 {
    339 	tmpfs_node_t *node = vp->v_data;
    340 #ifdef KASSERT
    341 	KASSERT(node != NULL);
    342 #endif
    343 	return node;
    344 }
    345 
    346 #endif /* _FS_TMPFS_TMPFS_H_ */
    347