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tmpfs.h revision 1.2
      1 /*	$NetBSD: tmpfs.h,v 1.2 2005/09/10 22:28:57 jmmv Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2005 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.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 #if !defined(_TMPFS_H_)
     40 #  define _TMPFS_H_
     41 #else
     42 #  error "tmpfs.h cannot be included multiple times."
     43 #endif
     44 
     45 /* ---------------------------------------------------------------------
     46  * KERNEL-SPECIFIC DEFINITIONS
     47  * --------------------------------------------------------------------- */
     48 
     49 #if defined(_KERNEL)
     50 
     51 #include <sys/dirent.h>
     52 #include <sys/mount.h>
     53 #include <sys/queue.h>
     54 #include <sys/vnode.h>
     55 
     56 #include <fs/tmpfs/tmpfs_pool.h>
     57 
     58 /* --------------------------------------------------------------------- */
     59 
     60 /*
     61  * This structure holds a directory entry.
     62  */
     63 struct tmpfs_dirent {
     64 	TAILQ_ENTRY(tmpfs_dirent)	td_entries;
     65 	uint16_t			td_namelen;
     66 	char *				td_name;
     67 	struct tmpfs_node *		td_node;
     68 };
     69 TAILQ_HEAD(tmpfs_dir, tmpfs_dirent);
     70 
     71 /* --------------------------------------------------------------------- */
     72 
     73 /*
     74  * This structure represents a node within tmpfs.
     75  */
     76 struct tmpfs_node {
     77 	LIST_ENTRY(tmpfs_node)	tn_entries;
     78 
     79 	enum vtype		tn_type;
     80 	ino_t			tn_id;
     81 
     82 #define	TMPFS_NODE_ACCESSED	(1 << 1)
     83 #define	TMPFS_NODE_MODIFIED	(1 << 2)
     84 #define	TMPFS_NODE_CHANGED	(1 << 3)
     85 	int			tn_status;
     86 
     87 	off_t			tn_size;
     88 
     89 	/* Attributes. */
     90 	uid_t			tn_uid;
     91 	gid_t			tn_gid;
     92 	mode_t			tn_mode;
     93 	int			tn_flags;
     94 	nlink_t			tn_links;
     95 	struct timespec		tn_atime;
     96 	struct timespec		tn_mtime;
     97 	struct timespec		tn_ctime;
     98 	struct timespec		tn_birthtime;
     99 	unsigned long		tn_gen;
    100 
    101 	struct vnode *		tn_vnode;
    102 
    103 	/* Used by tmpfs_lookup to store the affected directory entry during
    104 	 * DELETE and RENAME operations. */
    105 	struct tmpfs_dirent *	tn_lookup_dirent;
    106 
    107 	union {
    108 		/* Valid when tn_type == VBLK || tn_type == VCHR. */
    109 		struct {
    110 			dev_t			tn_rdev;
    111 		};
    112 
    113 		/* Valid when tn_type == VDIR. */
    114 		struct {
    115 			struct tmpfs_node *	tn_parent;
    116 			struct tmpfs_dir	tn_dir;
    117 
    118 			/* Used by tmpfs_readdir to speed up lookups. */
    119 			long			tn_readdir_lastn;
    120 			struct tmpfs_dirent *	tn_readdir_lastp;
    121 		};
    122 
    123 		/* Valid when tn_type == VLNK. */
    124 		struct {
    125 			char *			tn_link;
    126 		};
    127 
    128 		/* Valid when tn_type == VREG. */
    129 		struct {
    130 			struct uvm_object *	tn_aobj;
    131 			size_t			tn_aobj_pages;
    132 			vaddr_t			tn_va;
    133 		};
    134 	};
    135 };
    136 LIST_HEAD(tmpfs_node_list, tmpfs_node);
    137 
    138 /* --------------------------------------------------------------------- */
    139 
    140 /*
    141  * This structure holds the information relative to a tmpfs instance.
    142  */
    143 struct tmpfs_mount {
    144 	size_t			tm_pages_max;
    145 	size_t			tm_pages_used;
    146 
    147 	struct tmpfs_node *	tm_root;
    148 	struct netexport	tm_export;
    149 
    150 	ino_t			tm_nodes_max;
    151 	ino_t			tm_nodes_last;
    152 	struct tmpfs_node_list	tm_nodes_used;
    153 	struct tmpfs_node_list	tm_nodes_avail;
    154 
    155 	struct tmpfs_pool	tm_dirent_pool;
    156 	struct tmpfs_pool	tm_node_pool;
    157 	struct tmpfs_str_pool	tm_str_pool;
    158 };
    159 
    160 /* --------------------------------------------------------------------- */
    161 
    162 /*
    163  * This structure maps a file identifier to a tmpfs node.  Used by the
    164  * NFS code.
    165  */
    166 struct tmpfs_fid {
    167 	uint16_t		tf_len;
    168 	uint16_t		tf_pad;
    169 	ino_t			tf_id;
    170 	unsigned long		tf_gen;
    171 };
    172 
    173 /* --------------------------------------------------------------------- */
    174 
    175 /*
    176  * Prototypes for tmpfs_subr.c.
    177  */
    178 
    179 int	tmpfs_alloc_node(struct tmpfs_mount *, enum vtype,
    180 	    uid_t uid, gid_t gid, mode_t mode, struct tmpfs_node *,
    181 	    char *, dev_t, struct proc *, struct tmpfs_node **);
    182 void	tmpfs_free_node(struct tmpfs_mount *, struct tmpfs_node *);
    183 int	tmpfs_alloc_dirent(struct tmpfs_mount *, struct tmpfs_node *,
    184 	    const char *, uint16_t, struct tmpfs_dirent **);
    185 void	tmpfs_free_dirent(struct tmpfs_mount *, struct tmpfs_dirent *,
    186 	    boolean_t);
    187 int	tmpfs_alloc_vp(struct mount *, struct tmpfs_node *, struct vnode **);
    188 void	tmpfs_free_vp(struct vnode *);
    189 int	tmpfs_alloc_file(struct vnode *, struct vnode **, struct vattr *,
    190 	    struct componentname *, char *);
    191 void	tmpfs_dir_attach(struct vnode *, struct tmpfs_dirent *);
    192 void	tmpfs_dir_detach(struct vnode *, struct tmpfs_dirent *);
    193 struct tmpfs_dirent *	tmpfs_dir_lookup(struct tmpfs_node *node,
    194 			    struct componentname *cnp);
    195 int	tmpfs_dir_getdotdent(struct tmpfs_node *, struct uio *);
    196 int	tmpfs_dir_getdotdotdent(struct tmpfs_node *, struct uio *);
    197 int	tmpfs_dir_getdents(struct tmpfs_node *, struct uio *);
    198 int	tmpfs_reg_resize(struct vnode *, off_t);
    199 size_t	tmpfs_mem_info(boolean_t);
    200 int	tmpfs_chflags(struct vnode *, int, struct ucred *, struct proc *);
    201 int	tmpfs_chmod(struct vnode *, mode_t, struct ucred *, struct proc *);
    202 int	tmpfs_chown(struct vnode *, uid_t, gid_t, struct ucred *,
    203 	    struct proc *);
    204 int	tmpfs_chsize(struct vnode *, u_quad_t, struct ucred *, struct proc *);
    205 int	tmpfs_chtimes(struct vnode *, struct timespec *, struct timespec *,
    206 	    int, struct ucred *, struct proc *);
    207 
    208 /* --------------------------------------------------------------------- */
    209 
    210 /*
    211  * Convenience macros to simplify some logical expressions.
    212  */
    213 #define IMPLIES(a, b) (!(a) || (b))
    214 #define IFF(a, b) (IMPLIES(a, b) && IMPLIES(b, a))
    215 
    216 /* --------------------------------------------------------------------- */
    217 
    218 /*
    219  * Checks that the directory entry pointed by 'de' matches the name 'name'
    220  * with a length of 'len'.
    221  */
    222 #define TMPFS_DIRENT_MATCHES(de, name, len) \
    223     (de->td_namelen == (uint16_t)len && \
    224     memcmp((de)->td_name, (name), (de)->td_namelen) == 0)
    225 
    226 /* --------------------------------------------------------------------- */
    227 
    228 /*
    229  * Ensures that the node pointed by 'node' is a directory and that its
    230  * contents are consistent with respect to directories.
    231  */
    232 #define TMPFS_VALIDATE_DIR(node) \
    233     KASSERT((node)->tn_type == VDIR); \
    234     KASSERT((node)->tn_size % sizeof(struct tmpfs_dirent) == 0);
    235 
    236 /* --------------------------------------------------------------------- */
    237 
    238 /*
    239  * Memory management stuff.
    240  */
    241 
    242 /* Amount of memory pages to reserve for the system (e.g., to not use by
    243  * tmpfs).
    244  * XXX: Should this be tunable through sysctl, for instance? */
    245 #define TMPFS_PAGES_RESERVED (4 * 1024 * 1024 / PAGE_SIZE)
    246 
    247 /* Returns the available memory for the given file system, which can be
    248  * its limit (set during mount time) or the amount of free memory, whichever
    249  * is lower. */
    250 static inline size_t
    251 TMPFS_PAGES_MAX(struct tmpfs_mount *tmp)
    252 {
    253 	size_t freepages;
    254 
    255 	freepages = tmpfs_mem_info(FALSE);
    256 	if (freepages < TMPFS_PAGES_RESERVED)
    257 		freepages = 0;
    258 	else
    259 		freepages -= TMPFS_PAGES_RESERVED;
    260 
    261 	return MIN(tmp->tm_pages_max, freepages + tmp->tm_pages_used);
    262 }
    263 
    264 #define TMPFS_PAGES_AVAIL(tmp) (TMPFS_PAGES_MAX(tmp) - (tmp)->tm_pages_used)
    265 
    266 /* --------------------------------------------------------------------- */
    267 
    268 /*
    269  * Macros/functions to convert from generic data structures to tmpfs
    270  * specific ones.
    271  *
    272  * Macros are used when no sanity checks have to be done, as they provide
    273  * the fastest conversion.  On the other hand, inlined functions are used
    274  * when expensive sanity checks are enabled, mostly because the checks
    275  * have to be done separately from the return value.
    276  */
    277 
    278 #if defined(DIAGNOSTIC)
    279 static inline
    280 struct tmpfs_mount *
    281 VFS_TO_TMPFS(struct mount *mp)
    282 {
    283 	struct tmpfs_mount *tmp;
    284 
    285 	KASSERT((mp) != NULL && (mp)->mnt_data != NULL);
    286 	tmp = (struct tmpfs_mount *)(mp)->mnt_data;
    287 	KASSERT(TMPFS_PAGES_MAX(tmp) >= tmp->tm_pages_used);
    288 	return tmp;
    289 }
    290 
    291 static inline
    292 struct tmpfs_node *
    293 VP_TO_TMPFS_NODE(struct vnode *vp)
    294 {
    295 	struct tmpfs_node *node;
    296 
    297 	KASSERT((vp) != NULL && (vp)->v_data != NULL);
    298 	node = (struct tmpfs_node *)vp->v_data;
    299 	KASSERT(node->tn_size == vp->v_size);
    300 	return node;
    301 }
    302 
    303 static inline
    304 struct tmpfs_node *
    305 VP_TO_TMPFS_DIR(struct vnode *vp)
    306 {
    307 	struct tmpfs_node *node;
    308 
    309 	node = VP_TO_TMPFS_NODE(vp);
    310 	TMPFS_VALIDATE_DIR(node);
    311 	return node;
    312 }
    313 #else
    314 #	define VFS_TO_TMPFS(mp) ((struct tmpfs_mount *)mp->mnt_data)
    315 #	define VP_TO_TMPFS_NODE(vp) ((struct tmpfs_node *)vp->v_data)
    316 #	define VP_TO_TMPFS_DIR(vp) VP_TO_TMPFS_NODE(vp)
    317 #endif
    318 
    319 #endif /* _KERNEL */
    320 
    321 /* ---------------------------------------------------------------------
    322  * USER AND KERNEL DEFINITIONS
    323  * --------------------------------------------------------------------- */
    324 
    325 /*
    326  * This structure is used to communicate mount parameters between userland
    327  * and kernel space.
    328  */
    329 #define TMPFS_ARGS_VERSION	1
    330 struct tmpfs_args {
    331 	int			ta_version;
    332 
    333 	/* Size counters. */
    334 	ino_t			ta_nodes_max;
    335 	off_t			ta_size_max;
    336 
    337 	/* Root node attributes. */
    338 	uid_t			ta_root_uid;
    339 	gid_t			ta_root_gid;
    340 	mode_t			ta_root_mode;
    341 
    342 	/* Used to update NFS export properties.  Due to the way these
    343 	 * fields are used by mountd(8), they must come first, but as
    344 	 * I would like to remove this restriction, I'm placing them
    345 	 * here (there is no problem in doing so because, ATM, mountd(8)
    346 	 * does not recognize tmpfs).  XXX */
    347 	const char *		ta_fspec;
    348 	struct export_args	ta_export;
    349 };
    350