/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2007 Sun Microsystems, Inc.
 * All rights reserved.  Use is subject to license terms.
 */
/*
 * Copyright 2015 Joyent, Inc.
 */

#ifndef _SYS_FS_TMP_H
#define _SYS_FS_TMP_H

#ifdef  __cplusplus
extern "C" {
#endif

/*
 * tmpfs per-mount data structure.
 *
 * All fields are protected by tm_contents.
 * File renames on a particular file system are protected tm_renamelck.
 */
struct tmount {
        struct vfs      *tm_vfsp;       /* filesystem's vfs struct */
        struct tmpnode  *tm_rootnode;   /* root tmpnode */
        char            *tm_mntpath;    /* name of tmpfs mount point */
        ulong_t         tm_anonmax;     /* file system max anon reservation */
        pgcnt_t         tm_anonmem;     /* pages of reserved anon memory */
        dev_t           tm_dev;         /* unique dev # of mounted `device' */
        uint_t          tm_gen;         /* pseudo generation number for files */
        kmutex_t        tm_contents;    /* lock for tmount structure */
        kmutex_t        tm_renamelck;   /* rename lock for this mount */
};

/*
 * File system independent to tmpfs conversion macros
 */
#define VFSTOTM(vfsp)           ((struct tmount *)(vfsp)->vfs_data)
#define VTOTM(vp)               ((struct tmount *)(vp)->v_vfsp->vfs_data)
#define VTOTN(vp)               ((struct tmpnode *)(vp)->v_data)
#define TNTOV(tp)               ((tp)->tn_vnode)
#define tmpnode_hold(tp)        VN_HOLD(TNTOV(tp))
#define tmpnode_rele(tp)        VN_RELE(TNTOV(tp))

/*
 * enums
 */
enum de_op      { DE_CREATE, DE_MKDIR, DE_LINK, DE_RENAME }; /* direnter ops */
enum dr_op      { DR_REMOVE, DR_RMDIR, DR_RENAME };     /* dirremove ops */

/*
 * tmpfs_minfree is the amount (in pages) of anonymous memory that tmpfs
 * leaves free for the rest of the system.  E.g. in a system with 32MB of
 * configured swap space, if 16MB were reserved (leaving 16MB free),
 * tmpfs could allocate up to 16MB - tmpfs_minfree.  The default value
 * for tmpfs_minfree is btopr(TMPMINFREE) but it can cautiously patched
 * to a different number of pages.
 * NB: If tmpfs allocates too much swap space, other processes will be
 * unable to execute.
 */
#define TMPMINFREE      2 * 1024 * 1024 /* 2 Megabytes */

extern size_t   tmpfs_minfree;          /* Anonymous memory in pages */

/*
 * tmpfs can allocate only a certain percentage of kernel memory,
 * which is used for tmpnodes, directories, file names, etc.
 * This is statically set as TMPMAXFRACKMEM of physical memory.
 * The actual number of allocatable bytes can be patched in tmpfs_maxkmem.
 */
#define TMPMAXFRACKMEM  25      /* 1/25 of physical memory */

extern size_t   tmp_kmemspace;
extern size_t   tmpfs_maxkmem;  /* Allocatable kernel memory in bytes */

extern  void    tmpnode_init(struct tmount *, struct tmpnode *,
        struct vattr *, struct cred *);
extern  int     tmpnode_trunc(struct tmount *, struct tmpnode *, ulong_t);
extern  void    tmpnode_growmap(struct tmpnode *, ulong_t);
extern  int     tdirlookup(struct tmpnode *, char *, struct tmpnode **,
    struct cred *);
extern  int     tdirdelete(struct tmpnode *, struct tmpnode *, char *,
        enum dr_op, struct cred *);
extern  void    tdirinit(struct tmpnode *, struct tmpnode *);
extern  void    tdirtrunc(struct tmpnode *);
extern  void    *tmp_memalloc(size_t, int);
extern  void    tmp_memfree(void *, size_t);
extern  int     tmp_resv(struct tmount *, struct tmpnode *, size_t, int);
extern  int     tmp_taccess(void *, int, struct cred *);
extern  int     tmp_sticky_remove_access(struct tmpnode *, struct tmpnode *,
        struct cred *);
extern  int     tmp_convnum(char *, pgcnt_t *);
extern  int     tmp_convmode(char *, mode_t *);
extern  int     tdirenter(struct tmount *, struct tmpnode *, char *,
        enum de_op, struct tmpnode *, struct tmpnode *, struct vattr *,
        struct tmpnode **, struct cred *, caller_context_t *);

#define TMP_MUSTHAVE    0x01

#ifdef  __cplusplus
}
#endif

#endif  /* _SYS_FS_TMP_H */