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      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 #ifndef	_SYS_FS_TMP_H
     27 #define	_SYS_FS_TMP_H
     28 
     29 #pragma ident	"%Z%%M%	%I%	%E% SMI"
     30 
     31 #ifdef	__cplusplus
     32 extern "C" {
     33 #endif
     34 
     35 /*
     36  * tmpfs per-mount data structure.
     37  *
     38  * All fields are protected by tm_contents.
     39  * File renames on a particular file system are protected tm_renamelck.
     40  */
     41 struct tmount {
     42 	struct vfs	*tm_vfsp;	/* filesystem's vfs struct */
     43 	struct tmpnode	*tm_rootnode;	/* root tmpnode */
     44 	char 		*tm_mntpath;	/* name of tmpfs mount point */
     45 	ulong_t		tm_anonmax;	/* file system max anon reservation */
     46 	pgcnt_t		tm_anonmem;	/* pages of reserved anon memory */
     47 	dev_t		tm_dev;		/* unique dev # of mounted `device' */
     48 	uint_t		tm_gen;		/* pseudo generation number for files */
     49 	kmutex_t	tm_contents;	/* lock for tmount structure */
     50 	kmutex_t	tm_renamelck;	/* rename lock for this mount */
     51 };
     52 
     53 /*
     54  * File system independent to tmpfs conversion macros
     55  */
     56 #define	VFSTOTM(vfsp)		((struct tmount *)(vfsp)->vfs_data)
     57 #define	VTOTM(vp)		((struct tmount *)(vp)->v_vfsp->vfs_data)
     58 #define	VTOTN(vp)		((struct tmpnode *)(vp)->v_data)
     59 #define	TNTOV(tp)		((tp)->tn_vnode)
     60 #define	tmpnode_hold(tp)	VN_HOLD(TNTOV(tp))
     61 #define	tmpnode_rele(tp)	VN_RELE(TNTOV(tp))
     62 
     63 /*
     64  * enums
     65  */
     66 enum de_op	{ DE_CREATE, DE_MKDIR, DE_LINK, DE_RENAME }; /* direnter ops */
     67 enum dr_op	{ DR_REMOVE, DR_RMDIR, DR_RENAME };	/* dirremove ops */
     68 
     69 /*
     70  * tmpfs_minfree is the amount (in pages) of anonymous memory that tmpfs
     71  * leaves free for the rest of the system.  E.g. in a system with 32MB of
     72  * configured swap space, if 16MB were reserved (leaving 16MB free),
     73  * tmpfs could allocate up to 16MB - tmpfs_minfree.  The default value
     74  * for tmpfs_minfree is btopr(TMPMINFREE) but it can cautiously patched
     75  * to a different number of pages.
     76  * NB: If tmpfs allocates too much swap space, other processes will be
     77  * unable to execute.
     78  */
     79 #define	TMPMINFREE	2 * 1024 * 1024	/* 2 Megabytes */
     80 
     81 extern size_t	tmpfs_minfree;		/* Anonymous memory in pages */
     82 
     83 /*
     84  * tmpfs can allocate only a certain percentage of kernel memory,
     85  * which is used for tmpnodes, directories, file names, etc.
     86  * This is statically set as TMPMAXFRACKMEM of physical memory.
     87  * The actual number of allocatable bytes can be patched in tmpfs_maxkmem.
     88  */
     89 #define	TMPMAXFRACKMEM	25	/* 1/25 of physical memory */
     90 
     91 extern size_t 	tmp_kmemspace;
     92 extern size_t	tmpfs_maxkmem;	/* Allocatable kernel memory in bytes */
     93 
     94 extern	void	tmpnode_init(struct tmount *, struct tmpnode *,
     95 	struct vattr *, struct cred *);
     96 extern	int	tmpnode_trunc(struct tmount *, struct tmpnode *, ulong_t);
     97 extern	void	tmpnode_growmap(struct tmpnode *, ulong_t);
     98 extern	int	tdirlookup(struct tmpnode *, char *, struct tmpnode **,
     99     struct cred *);
    100 extern	int	tdirdelete(struct tmpnode *, struct tmpnode *, char *,
    101 	enum dr_op, struct cred *);
    102 extern	void	tdirinit(struct tmpnode *, struct tmpnode *);
    103 extern	void	tdirtrunc(struct tmpnode *);
    104 extern	void	*tmp_memalloc(size_t, int);
    105 extern	void	tmp_memfree(void *, size_t);
    106 extern	int	tmp_resv(struct tmount *, struct tmpnode *, size_t, int);
    107 extern	int	tmp_taccess(void *, int, struct cred *);
    108 extern	int	tmp_sticky_remove_access(struct tmpnode *, struct tmpnode *,
    109 	struct cred *);
    110 extern	int	tmp_convnum(char *, pgcnt_t *);
    111 extern	int	tdirenter(struct tmount *, struct tmpnode *, char *,
    112 	enum de_op, struct tmpnode *, struct tmpnode *, struct vattr *,
    113 	struct tmpnode **, struct cred *, caller_context_t *);
    114 
    115 #define	TMP_MUSTHAVE	0x01
    116 
    117 #ifdef	__cplusplus
    118 }
    119 #endif
    120 
    121 #endif	/* _SYS_FS_TMP_H */
    122