/*
 * 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 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Loopback mount info - one per mount
 */

#ifndef _SYS_FS_LOFS_INFO_H
#define _SYS_FS_LOFS_INFO_H

#ifdef _KERNEL
#include <sys/vfs_opreg.h>
#endif

#ifdef  __cplusplus
extern "C" {
#endif

struct lnode;

struct lobucket {
        kmutex_t        lh_lock;        /* lock protecting bucket contents */
        struct lnode    *lh_chain;      /* vnode chain for this bucket */
        uint_t          lh_count;       /* Number of vnodes in chain */
        /* Pad up to 64-byte boundary to avoid false sharing */
#ifdef _LP64
        char            _pad[44];
#else
        char            _pad[48];
#endif
};

struct lo_retired_ht {
        struct lo_retired_ht    *lrh_next;
        struct lobucket         *lrh_table;
        uint_t                  lrh_size;
};

struct loinfo {
        struct vfs      *li_realvfs;    /* real vfs of mount */
        struct vfs      *li_mountvfs;   /* loopback vfs */
        struct vnode    *li_rootvp;     /* root vnode of this vfs */
        int              li_mflag;      /* mount flags to inherit */
        int              li_dflag;      /* mount flags to not inherit */
        uint_t           li_refct;      /* # outstanding vnodes */
        volatile uint_t  li_htsize;     /* # buckets in hashtable */
        struct lobucket *volatile li_hashtable; /* table of per-mount vnodes */
        struct lfsnode  *li_lfs;        /* list of other vfss */
        kmutex_t         li_lfslock;    /* lock protecting li_lfs */
        kmutex_t         li_htlock;     /* protect hashtable, htsize, retired */
        struct lo_retired_ht *li_retired; /* list of retired hashtables */
        int              li_flag;       /* filesystem behavior flags */
};

/* inheritable mount flags - propagated from real vfs to loopback */
#define INHERIT_VFS_FLAG        \
        (VFS_RDONLY|VFS_NOSETUID|VFS_NODEVICES|VFS_XATTR|VFS_NBMAND|VFS_NOEXEC)

/*
 * "nosub" is used to provide NFS server-like semantics for lo_lookup(): never
 * traverse mount points for sub-mounts.  The lookup will instead look under
 * the mount point.
 */
#define MNTOPT_LOFS_NOSUB       "nosub"
#define MNTOPT_LOFS_SUB         "sub"

/*
 * Flag values (for li_flag)
 */
#define LO_NOSUB        0x02    /* don't traverse sub-mounts */

/*
 * lfsnodes are allocated as new real vfs's are encountered
 * when looking up things in a loopback name space
 * It contains a new vfs which is paired with the real vfs
 * so that vfs ops (fsstat) can get to the correct real vfs
 * given just a loopback vfs
 */
struct lfsnode {
        struct lfsnode  *lfs_next;      /* next in loinfo list */
        struct vfs      *lfs_realvfs;   /* real vfs */
        struct vnode    *lfs_realrootvp; /* real root vp */
        struct vfs       lfs_vfs;       /* new loopback vfs */
};

#define vtoli(VFSP)     ((struct loinfo *)((VFSP)->vfs_data))

#ifdef _KERNEL
extern struct vfs *lo_realvfs(struct vfs *, struct vnode **);
extern void lofs_subrinit(void);
extern void lofs_subrfini(void);

extern void lsetup(struct loinfo *, uint_t);
extern void ldestroy(struct loinfo *);

extern const struct fs_operation_def lo_vnodeops_template[];

extern struct vnodeops *lo_vnodeops;
extern vfsops_t *lo_vfsops;
extern struct mod_ops mod_fsops;

#endif /* _KERNEL */


#ifdef  __cplusplus
}
#endif

#endif  /* _SYS_FS_LOFS_INFO_H */