common/sys/vfs.h

	vfs.h revision f48205be61a214698b763ff550ab9e657525104c
/*
 * 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 (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
/*    All Rights Reserved   */

/*
 * Portions of this source code were derived from Berkeley 4.3 BSD
 * under license from the Regents of the University of California.
 */

#ifndef _SYS_VFS_H
#define _SYS_VFS_H

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sys/types.h>
#include <sys/t_lock.h>
#include <sys/cred.h>
#include <sys/vnode.h>
#include <sys/statvfs.h>
#include <sys/refstr.h>
#include <sys/avl.h>

#ifdef  __cplusplus
extern "C" {
#endif

/*
 * Data associated with mounted file systems.
 */

/*
 * Operations vector.  This is used internal to the kernel; file systems
 * supply their list of operations via vfs_setfsops().
 */

typedef struct vfsops vfsops_t;

/*
 * File system identifier. Should be unique (at least per machine).
 */
typedef struct {
    int val[2];         /* file system id type */
} fsid_t;

/*
 * File identifier.  Should be unique per filesystem on a single
 * machine.  This is typically called by a stateless file server
 * in order to generate "file handles".
 *
 * Do not change the definition of struct fid ... fid_t without
 * letting the CacheFS group know about it!  They will have to do at
 * least two things, in the same change that changes this structure:
 *   1. change CFSVERSION in usr/src/uts/common/sys/fs/cachefs_fs.h
 *   2. put the old version # in the canupgrade array
 *  in cachfs_upgrade() in usr/src/cmd/fs.d/cachefs/fsck/fsck.c
 * This is necessary because CacheFS stores FIDs on disk.
 *
 * Many underlying file systems cast a struct fid into other
 * file system dependent structures which may require 4 byte alignment.
 * Because a fid starts with a short it may not be 4 byte aligned, the
 * fid_pad will force the alignment.
 */
#define MAXFIDSZ    64
#define OLD_MAXFIDSZ    16

typedef struct fid {
    union {
        long fid_pad;
        struct {
            ushort_t len;   /* length of data in bytes */
            char    data[MAXFIDSZ]; /* data (variable len) */
        } _fid;
    } un;
} fid_t;

#ifdef _SYSCALL32
/*
 * Solaris 64 - use old-style cache format with 32-bit aligned fid for on-disk
 * struct compatibility.
 */
typedef struct fid32 {
    union {
        int32_t fid_pad;
        struct {
            uint16_t  len;   /* length of data in bytes */
            char    data[MAXFIDSZ]; /* data (variable len) */
        } _fid;
    } un;
} fid32_t;
#else /* not _SYSCALL32 */
#define fid32   fid
typedef fid_t   fid32_t;
#endif /* _SYSCALL32 */

#define fid_len     un._fid.len
#define fid_data    un._fid.data

/*
 * Structure defining a mount option for a filesystem.
 * option names are found in mntent.h
 */
typedef struct mntopt {
    char    *mo_name;   /* option name */
    char    **mo_cancel;    /* list of options cancelled by this one */
    char    *mo_arg;    /* argument string for this option */
    int mo_flags;   /* flags for this mount option */
    void    *mo_data;   /* filesystem specific data */
} mntopt_t;

/*
 * Flags that apply to mount options
 */

#define MO_SET      0x01        /* option is set */
#define MO_NODISPLAY    0x02        /* option not listed in mnttab */
#define MO_HASVALUE 0x04        /* option takes a value */
#define MO_IGNORE   0x08        /* option ignored by parser */
#define MO_DEFAULT  MO_SET      /* option is on by default */
#define MO_TAG      0x10        /* flags a tag set by user program */
#define MO_EMPTY    0x20        /* empty space in option table */

#define VFS_NOFORCEOPT  0x01        /* honor MO_IGNORE (don't set option) */
#define VFS_DISPLAY 0x02        /* Turn off MO_NODISPLAY bit for opt */
#define VFS_NODISPLAY   0x04        /* Turn on MO_NODISPLAY bit for opt */
#define VFS_CREATEOPT   0x08        /* Create the opt if it's not there */

/*
 * Structure holding mount option strings for the mounted file system.
 */
typedef struct mntopts {
    uint_t      mo_count;       /* number of entries in table */
    mntopt_t    *mo_list;       /* list of mount options */
} mntopts_t;

/*
 * The kstat structures associated with the vopstats are kept in an
 * AVL tree.  This is to avoid the case where a file system does not
 * use a unique fsid_t for each vfs (e.g., namefs).  In order to do
 * this, we need a structure that the AVL tree can use that also
 * references the kstat.
 * Note that the vks_fsid is generated from the value reported by
 * VFS_STATVFS().
 */
typedef struct vskstat_anchor {
    avl_node_t  vsk_node;   /* Required for use by AVL routines */
    kstat_t     *vsk_ksp;   /* kstat structure for vopstats */
    ulong_t     vsk_fsid;   /* fsid associated w/this FS */
} vsk_anchor_t;

extern avl_tree_t   vskstat_tree;
extern kmutex_t     vskstat_tree_lock;

/*
 * Structure per mounted file system.  Each mounted file system has
 * an array of operations and an instance record.
 *
 * The file systems are kept on a doubly linked circular list headed by
 * "rootvfs".
 * File system implementations should not access this list;
 * it's intended for use only in the kernel's vfs layer.
 *
 * Each zone also has its own list of mounts, containing filesystems mounted
 * somewhere within the filesystem tree rooted at the zone's rootpath.  The
 * list is doubly linked to match the global list.
 *
 * mnttab locking: the in-kernel mnttab uses the vfs_mntpt, vfs_resource and
 * vfs_mntopts fields in the vfs_t. mntpt and resource are refstr_ts that
 * are set at mount time and can only be modified during a remount.
 * It is safe to read these fields if you can prevent a remount on the vfs,
 * or through the convenience funcs vfs_getmntpoint() and vfs_getresource().
 * The mntopts field may only be accessed through the provided convenience
 * functions, as it is protected by the vfs list lock. Modifying a mount
 * option requires grabbing the vfs list write lock, which can be a very
 * high latency lock.
 */
struct zone;        /* from zone.h */
struct fem_head;    /* from fem.h */

/*
 * Private vfs data, NOT to be used by a file system implementation.
 */
typedef struct vfs_impl {
    struct fem_head *vi_femhead;        /* fs monitoring */
    /*
     * Support for statistics on the vnode operations
     */
    vsk_anchor_t    *vi_vskap;      /* anchor for vopstats' kstat */
    vopstats_t  *vi_fstypevsp;      /* ptr to per-fstype vopstats */
    vopstats_t  vi_vopstats;        /* per-mount vnode op stats */
} vfs_impl_t;

typedef struct vfs {
    struct vfs  *vfs_next;      /* next VFS in VFS list */
    struct vfs  *vfs_prev;      /* prev VFS in VFS list */

/* vfs_op should not be used directly.  Accessor functions are provided */
    vfsops_t    *vfs_op;        /* operations on VFS */

    struct vnode    *vfs_vnodecovered;  /* vnode mounted on */
    uint_t      vfs_flag;       /* flags */
    uint_t      vfs_bsize;      /* native block size */
    int     vfs_fstype;     /* file system type index */
    fsid_t      vfs_fsid;       /* file system id */
    void        *vfs_data;      /* private data */
    dev_t       vfs_dev;        /* device of mounted VFS */
    ulong_t     vfs_bcount;     /* I/O count (accounting) */
    struct vfs  *vfs_list;      /* sync list pointer */
    struct vfs  *vfs_hash;      /* hash list pointer */
    ksema_t     vfs_reflock;        /* mount/unmount/sync lock */
    uint_t      vfs_count;      /* vfs reference count */
    mntopts_t   vfs_mntopts;        /* options mounted with */
    refstr_t    *vfs_resource;      /* mounted resource name */
    refstr_t    *vfs_mntpt;     /* mount point name */
    time_t      vfs_mtime;      /* time we were mounted */
    vfs_impl_t  *vfs_implp;     /* impl specific data */
    /*
     * Zones support.  Note that the zone that "owns" the mount isn't
     * necessarily the same as the zone in which the zone is visible.
     * That is, vfs_zone and (vfs_zone_next|vfs_zone_prev) may refer to
     * different zones.
     */
    struct zone *vfs_zone;      /* zone that owns the mount */
    struct vfs  *vfs_zone_next;     /* next VFS visible in zone */
    struct vfs  *vfs_zone_prev;     /* prev VFS visible in zone */
} vfs_t;

#define vfs_femhead vfs_implp->vi_femhead
#define vfs_vskap   vfs_implp->vi_vskap
#define vfs_fstypevsp   vfs_implp->vi_fstypevsp
#define vfs_vopstats    vfs_implp->vi_vopstats

/*
 * VFS flags.
 */
#define VFS_RDONLY  0x01        /* read-only vfs */
#define VFS_NOMNTTAB    0x02        /* vfs not seen in mnttab */
#define VFS_NOSETUID    0x08        /* setuid disallowed */
#define VFS_REMOUNT 0x10        /* modify mount options only */
#define VFS_NOTRUNC 0x20        /* does not truncate long file names */
#define VFS_UNLINKABLE  0x40        /* unlink(2) can be applied to root */
#define VFS_PXFS    0x80        /* clustering: global fs proxy vfs */
#define VFS_UNMOUNTED   0x100       /* file system has been unmounted */
#define VFS_NBMAND  0x200       /* allow non-blocking mandatory locks */
#define VFS_XATTR   0x400       /* fs supports extended attributes */
#define VFS_NODEVICES   0x800       /* device-special files disallowed */
#define VFS_NOEXEC  0x1000      /* executables disallowed */
#define VFS_STATS   0x2000      /* file system can collect stats */
#define VFS_XID     0x4000      /* file system supports extended ids */

#define VFS_NORESOURCE  "unspecified_resource"
#define VFS_NOMNTPT "unspecified_mountpoint"

/*
 * Argument structure for mount(2).
 *
 * Flags are defined in <sys/mount.h>.
 *
 * Note that if the MS_SYSSPACE bit is set in flags, the pointer fields in
 * this structure are to be interpreted as kernel addresses.  File systems
 * should be prepared for this possibility.
 */
struct mounta {
    char    *spec;
    char    *dir;
    int flags;
    char    *fstype;
    char    *dataptr;
    int datalen;
    char    *optptr;
    int optlen;
};

/*
 * Reasons for calling the vfs_mountroot() operation.
 */
enum whymountroot { ROOT_INIT, ROOT_REMOUNT, ROOT_UNMOUNT};
typedef enum whymountroot whymountroot_t;

/*
 * Reasons for calling the VFS_VNSTATE():
 */
enum vntrans {
    VNTRANS_EXISTS,
    VNTRANS_IDLED,
    VNTRANS_RECLAIMED,
    VNTRANS_DESTROYED
};
typedef enum vntrans vntrans_t;

/*
 * VFS_OPS defines all the vfs operations.  It is used to define
 * the vfsops structure (below) and the fs_func_p union (vfs_opreg.h).
 */
#define VFS_OPS                             \
    int (*vfs_mount)(vfs_t *, vnode_t *, struct mounta *, cred_t *); \
    int (*vfs_unmount)(vfs_t *, int, cred_t *);         \
    int (*vfs_root)(vfs_t *, vnode_t **);           \
    int (*vfs_statvfs)(vfs_t *, statvfs64_t *);         \
    int (*vfs_sync)(vfs_t *, short, cred_t *);          \
    int (*vfs_vget)(vfs_t *, vnode_t **, fid_t *);      \
    int (*vfs_mountroot)(vfs_t *, enum whymountroot);       \
    void    (*vfs_freevfs)(vfs_t *);                \
    int (*vfs_vnstate)(vfs_t *, vnode_t *, vntrans_t)   /* NB: No ";" */

/*
 * Operations supported on virtual file system.
 */
struct vfsops {
    VFS_OPS;    /* Signature of all vfs operations (vfsops) */
};

extern int  fsop_mount(vfs_t *, vnode_t *, struct mounta *, cred_t *);
extern int  fsop_unmount(vfs_t *, int, cred_t *);
extern int  fsop_root(vfs_t *, vnode_t **);
extern int  fsop_statfs(vfs_t *, statvfs64_t *);
extern int  fsop_sync(vfs_t *, short, cred_t *);
extern int  fsop_vget(vfs_t *, vnode_t **, fid_t *);
extern int  fsop_mountroot(vfs_t *, enum whymountroot);
extern void fsop_freefs(vfs_t *);
extern int  fsop_sync_by_kind(int, short, cred_t *);
extern int  fsop_vnstate(vfs_t *, vnode_t *, vntrans_t);

#define VFS_MOUNT(vfsp, mvp, uap, cr) fsop_mount(vfsp, mvp, uap, cr)
#define VFS_UNMOUNT(vfsp, flag, cr) fsop_unmount(vfsp, flag, cr)
#define VFS_ROOT(vfsp, vpp) fsop_root(vfsp, vpp)
#define VFS_STATVFS(vfsp, sp) fsop_statfs(vfsp, sp)
#define VFS_SYNC(vfsp, flag, cr) fsop_sync(vfsp, flag, cr)
#define VFS_VGET(vfsp, vpp, fidp) fsop_vget(vfsp, vpp, fidp)
#define VFS_MOUNTROOT(vfsp, init) fsop_mountroot(vfsp, init)
#define VFS_FREEVFS(vfsp) fsop_freefs(vfsp)
#define VFS_VNSTATE(vfsp, vn, ns)   fsop_vnstate(vfsp, vn, ns)

#define VFSNAME_MOUNT       "mount"
#define VFSNAME_UNMOUNT     "unmount"
#define VFSNAME_ROOT        "root"
#define VFSNAME_STATVFS     "statvfs"
#define VFSNAME_SYNC        "sync"
#define VFSNAME_VGET        "vget"
#define VFSNAME_MOUNTROOT   "mountroot"
#define VFSNAME_FREEVFS     "freevfs"
#define VFSNAME_VNSTATE     "vnstate"
/*
 * Filesystem type switch table.
 */

typedef struct vfssw {
    char        *vsw_name;  /* type name -- max len _ST_FSTYPSZ */
    int     (*vsw_init) (int, char *);
                /* init routine (for non-loadable fs only) */
    int     vsw_flag;   /* flags */
    mntopts_t   vsw_optproto;   /* mount options table prototype */
    uint_t      vsw_count;  /* count of references */
    kmutex_t    vsw_lock;   /* lock to protect vsw_count */
    vfsops_t    vsw_vfsops; /* filesystem operations vector */
} vfssw_t;

/*
 * Filesystem type definition record.  All file systems must export a record
 * of this type through their modlfs structure.
 */

typedef struct vfsdef_v3 {
    int     def_version;    /* structure version, must be first */
    char        *name;      /* filesystem type name */
    int     (*init) (int, char *);  /* init routine */
    int     flags;      /* filesystem flags */
    mntopts_t   *optproto;  /* mount options table prototype */
} vfsdef_v3;

typedef struct vfsdef_v3 vfsdef_t;

enum {
    VFSDEF_VERSION = 3
};

/*
 * flags for vfssw and vfsdef
 */
#define VSW_HASPROTO    0x01    /* struct has a mount options prototype */
#define VSW_CANRWRO 0x02    /* file system can transition from rw to ro */
#define VSW_CANREMOUNT  0x04    /* file system supports remounts */
#define VSW_NOTZONESAFE 0x08    /* zone_enter(2) should fail for these files */
#define VSW_VOLATILEDEV 0x10    /* vfs_dev can change each time fs is mounted */
#define VSW_STATS   0x20    /* file system can collect stats */
#define VSW_XID     0x40    /* file system supports extended ids */

#define VSW_INSTALLED   0x8000  /* this vsw is associated with a file system */

#if defined(_KERNEL)
/*
 * Public operations.
 */
struct umounta;
struct statvfsa;
struct fstatvfsa;

void    vfs_freevfsops(vfsops_t *);
int vfs_freevfsops_by_type(int);
void    vfs_setops(vfs_t *, vfsops_t *);
vfsops_t *vfs_getops(vfs_t *vfsp);
int vfs_matchops(vfs_t *, vfsops_t *);
int vfs_can_sync(vfs_t *vfsp);
void    vfs_init(vfs_t *vfsp, vfsops_t *, void *);
void    vfsimpl_setup(vfs_t *vfsp);
void    vfsimpl_teardown(vfs_t *vfsp);
void    vn_exists(vnode_t *);
void    vn_idle(vnode_t *);
void    vn_reclaim(vnode_t *);
void    vn_invalid(vnode_t *);

int rootconf(void);
int svm_rootconf(void);
int domount(char *, struct mounta *, vnode_t *, struct cred *,
        struct vfs **);
int dounmount(struct vfs *, int, cred_t *);
int vfs_lock(struct vfs *);
int vfs_rlock(struct vfs *);
void    vfs_lock_wait(struct vfs *);
void    vfs_rlock_wait(struct vfs *);
void    vfs_unlock(struct vfs *);
int vfs_lock_held(struct vfs *);
struct  _kthread *vfs_lock_owner(struct vfs *);
void    sync(void);
void    vfs_sync(int);
void    vfs_mountroot(void);
void    vfs_add(vnode_t *, struct vfs *, int);
void    vfs_remove(struct vfs *);

/* The following functions are not for general use by filesystems */

void    vfs_createopttbl(mntopts_t *, const char *);
void    vfs_copyopttbl(const mntopts_t *, mntopts_t *);
void    vfs_mergeopttbl(const mntopts_t *, const mntopts_t *, mntopts_t *);
void    vfs_freeopttbl(mntopts_t *);
void    vfs_parsemntopts(mntopts_t *, char *, int);
int vfs_buildoptionstr(const mntopts_t *, char *, int);
struct mntopt *vfs_hasopt(const mntopts_t *, const char *);
void    vfs_mnttab_modtimeupd(void);

void    vfs_clearmntopt(struct vfs *, const char *);
void    vfs_setmntopt(struct vfs *, const char *, const char *, int);
void    vfs_setresource(struct vfs *, const char *);
void    vfs_setmntpoint(struct vfs *, const char *);
refstr_t *vfs_getresource(const struct vfs *);
refstr_t *vfs_getmntpoint(const struct vfs *);
int vfs_optionisset(const struct vfs *, const char *, char **);
int vfs_settag(uint_t, uint_t, const char *, const char *, cred_t *);
int vfs_clrtag(uint_t, uint_t, const char *, const char *, cred_t *);
void    vfs_syncall(void);
void    vfs_syncprogress(void);
void    vfsinit(void);
void    vfs_unmountall(void);
void    vfs_make_fsid(fsid_t *, dev_t, int);
void    vfs_addmip(dev_t, struct vfs *);
void    vfs_delmip(struct vfs *);
int vfs_devismounted(dev_t);
int vfs_devmounting(dev_t, struct vfs *);
int vfs_opsinuse(vfsops_t *);
struct vfs *getvfs(fsid_t *);
struct vfs *vfs_dev2vfsp(dev_t);
struct vfs *vfs_mntpoint2vfsp(const char *);
struct vfssw *allocate_vfssw(char *);
struct vfssw *vfs_getvfssw(char *);
struct vfssw *vfs_getvfsswbyname(char *);
struct vfssw *vfs_getvfsswbyvfsops(vfsops_t *);
void    vfs_refvfssw(struct vfssw *);
void    vfs_unrefvfssw(struct vfssw *);
uint_t  vf_to_stf(uint_t);
void    vfs_mnttab_modtime(timespec_t *);
void    vfs_mnttab_poll(timespec_t *, struct pollhead **);

void    vfs_list_lock(void);
void    vfs_list_read_lock(void);
void    vfs_list_unlock(void);
void    vfs_list_add(struct vfs *);
void    vfs_list_remove(struct vfs *);
void    vfs_hold(vfs_t *vfsp);
void    vfs_rele(vfs_t *vfsp);
void    fs_freevfs(vfs_t *);
void    vfs_root_redev(vfs_t *vfsp, dev_t ndev, int fstype);

int vfs_zone_change_safe(vfs_t *);

#define VFSHASH(maj, min) (((int)((maj)+(min))) & (vfshsz - 1))
#define VFS_ON_LIST(vfsp) \
    ((vfsp)->vfs_next != (vfsp) && (vfsp)->vfs_next != NULL)

/*
 * Globals.
 */

extern struct vfssw vfssw[];        /* table of filesystem types */
extern krwlock_t vfssw_lock;
extern char rootfstype[];       /* name of root fstype */
extern const int nfstype;       /* # of elements in vfssw array */
extern vfsops_t *EIO_vfsops;        /* operations for vfs being torn-down */

/*
 * The following variables are private to the the kernel's vfs layer.  File
 * system implementations should not access them.
 */
extern struct vfs *rootvfs;     /* ptr to root vfs structure */
typedef struct {
    struct vfs *rvfs_head;      /* head vfs in chain */
    kmutex_t rvfs_lock;     /* mutex protecting this chain */
    uint32_t rvfs_len;      /* length of this chain */
} rvfs_t;
extern rvfs_t *rvfs_list;
extern int vfshsz;          /* # of elements in rvfs_head array */
extern const mntopts_t vfs_mntopts; /* globally recognized options */

#endif /* defined(_KERNEL) */

#define VFS_HOLD(vfsp) { \
    vfs_hold(vfsp); \
}

#define VFS_RELE(vfsp)  { \
    vfs_rele(vfsp); \
}

#define VFS_INIT(vfsp, op, data) { \
    vfs_init((vfsp), (op), (data)); \
    vfsimpl_setup((vfsp)); \
}


#define VFS_INSTALLED(vfsswp)   (((vfsswp)->vsw_flag & VSW_INSTALLED) != 0)
#define ALLOCATED_VFSSW(vswp)       ((vswp)->vsw_name[0] != '\0')
#define RLOCK_VFSSW()           (rw_enter(&vfssw_lock, RW_READER))
#define RUNLOCK_VFSSW()         (rw_exit(&vfssw_lock))
#define WLOCK_VFSSW()           (rw_enter(&vfssw_lock, RW_WRITER))
#define WUNLOCK_VFSSW()         (rw_exit(&vfssw_lock))
#define VFSSW_LOCKED()          (RW_LOCK_HELD(&vfssw_lock))
#define VFSSW_WRITE_LOCKED()        (RW_WRITE_HELD(&vfssw_lock))
/*
 * VFS_SYNC flags.
 */
#define SYNC_ATTR   0x01        /* sync attributes only */
#define SYNC_CLOSE  0x02        /* close open file */
#define SYNC_ALL    0x04        /* force to sync all fs */

#ifdef  __cplusplus
}
#endif

#endif  /* _SYS_VFS_H */