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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 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
     22 /*	  All Rights Reserved	*/
     23 
     24 
     25 /*
     26  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
     27  * Use is subject to license terms.
     28  */
     29 
     30 #ifndef	_SYS_FS_SNODE_H
     31 #define	_SYS_FS_SNODE_H
     32 
     33 #pragma ident	"%Z%%M%	%I%	%E% SMI"
     34 
     35 #include <sys/types.h>
     36 #include <sys/t_lock.h>
     37 #include <sys/cred.h>
     38 #include <sys/vnode.h>
     39 
     40 /*
     41  * The snode represents a special file in any filesystem.  There is
     42  * one snode for each active special file.  Filesystems that support
     43  * special files use specvp(vp, dev, type, cr) to convert a normal
     44  * vnode to a special vnode in the ops lookup() and create().
     45  *
     46  * To handle having multiple snodes that represent the same
     47  * underlying device vnode without cache aliasing problems,
     48  * the s_commonvp is used to point to the "common" vnode used for
     49  * caching data.  If an snode is created internally by the kernel,
     50  * then the s_realvp field is NULL and s_commonvp points to s_vnode.
     51  * The other snodes which are created as a result of a lookup of a
     52  * device in a file system have s_realvp pointing to the vp which
     53  * represents the device in the file system while the s_commonvp points
     54  * into the "common" vnode for the device in another snode.
     55  */
     56 
     57 /*
     58  * Include SUNDDI type definitions so that the s_dip tag doesn't urk.
     59  */
     60 #include <sys/dditypes.h>
     61 
     62 #ifdef	__cplusplus
     63 extern "C" {
     64 #endif
     65 
     66 struct snode {
     67 	/* These fields are protected by stable_lock */
     68 	struct	snode *s_next;		/* must be first */
     69 	struct	vnode *s_vnode;		/* vnode associated with this snode */
     70 	/*
     71 	 * These fields are initialized once.
     72 	 */
     73 	struct	vnode *s_realvp;	/* vnode for the fs entry (if any) */
     74 	struct	vnode *s_commonvp;	/* common device vnode */
     75 	dev_t	s_dev;			/* device the snode represents */
     76 	dev_info_t *s_dip;		/* dev_info (common snode only) */
     77 	/*
     78 	 * Doesn't always need to be updated atomically because it is a hint.
     79 	 * No lock required.
     80 	 */
     81 	u_offset_t s_nextr;		/* next byte read offset (read-ahead) */
     82 
     83 	/* These fields are protected by spec_syncbusy */
     84 	struct	snode *s_list;		/* used for syncing */
     85 	/* These fields are protected by s_lock */
     86 	struct devplcy *s_plcy;		/* device node open policy (cs only) */
     87 	u_offset_t s_size;		/* block device size in bytes */
     88 	uint_t	s_flag;			/* flags, see below */
     89 	dev_t	s_fsid;			/* file system identifier */
     90 	time_t  s_atime;		/* time of last access */
     91 	time_t  s_mtime;		/* time of last modification */
     92 	time_t  s_ctime;		/* time of last attributes change */
     93 	int	s_count;		/* count of opened references */
     94 	long	s_mapcnt;		/* count of mappings of pages */
     95 	/* The locks themselves */
     96 	kmutex_t	s_lock;		/* protects snode fields */
     97 	kcondvar_t	s_cv;		/* synchronize open/closes */
     98 };
     99 
    100 /* flags */
    101 #define	SUPD		0x01		/* update device access time */
    102 #define	SACC		0x02		/* update device modification time */
    103 #define	SCHG		0x04		/* update device change time */
    104 #define	SPRIV		0x08		/* file open for private access */
    105 #define	SLOFFSET	0x10		/* device takes 64-bit uio offsets */
    106 #define	SLOCKED		0x20		/* use to serialize open/closes */
    107 #define	SWANT		0x40		/* some process waiting on lock */
    108 #define	SANYOFFSET	0x80		/* device takes any uio offset */
    109 #define	SCLONE		0x100		/* represents a cloned device */
    110 #define	SNEEDCLOSE	0x200		/* needs driver close call */
    111 #define	SDIPSET		0x400		/* the vnode has an association with */
    112 					/* the driver, even though it may */
    113 					/* not currently have an association */
    114 					/* with a specific hardware instance */
    115 					/* if s_dip is NULL */
    116 #define	SSIZEVALID	0x800		/* s_size field is valid */
    117 #define	SMUXED		0x1000		/* this snode is a stream that has */
    118 					/* been multiplexed */
    119 #define	SSELFCLONE	0x2000		/* represents a self cloning device */
    120 #define	SNOFLUSH	0x4000		/* do not flush device on fsync */
    121 #define	SCLOSING	0x8000		/* in last close(9E) */
    122 #define	SFENCED		0x10000		/* snode fenced off for I/O retire */
    123 
    124 #ifdef _KERNEL
    125 /*
    126  * Convert between vnode and snode
    127  */
    128 #define	VTOS(vp)	((struct snode *)((vp)->v_data))
    129 #define	VTOCS(vp)	(VTOS(VTOS(vp)->s_commonvp))
    130 #define	STOV(sp)	((sp)->s_vnode)
    131 
    132 extern int spec_debug;
    133 
    134 #define	SPEC_FENCE_DEBUG	0x0001	/* emit fence related debug messages */
    135 
    136 #define	FENDBG(args)	if (spec_debug & SPEC_FENCE_DEBUG) cmn_err args
    137 
    138 
    139 /*
    140  * Forward declarations
    141  */
    142 struct vfssw;
    143 struct cred;
    144 
    145 extern struct vfs	spec_vfs;
    146 extern struct vfsops	spec_vfsops;
    147 extern struct kmem_cache *snode_cache;
    148 
    149 /*
    150  * specfs functions
    151  */
    152 offset_t	spec_maxoffset(struct vnode *);
    153 struct vnodeops	*spec_getvnodeops(void);
    154 struct vnode *specvp(struct vnode *, dev_t, vtype_t, struct cred *);
    155 struct vnode *makespecvp(dev_t, vtype_t);
    156 struct vnode *other_specvp(struct vnode *);
    157 struct vnode *common_specvp(struct vnode *);
    158 struct vnode *specfind(dev_t, vtype_t);
    159 struct vnode *commonvp(dev_t, vtype_t);
    160 struct vnode *makectty(vnode_t *);
    161 void	sdelete(struct snode *);
    162 void 	smark(struct snode *, int);
    163 int	specinit(int, char *);
    164 int	device_close(struct vnode *, int, struct cred *);
    165 int	spec_putpage(struct vnode *, offset_t, size_t, int, struct cred *,
    166 		caller_context_t *);
    167 int	spec_segmap(dev_t, off_t, struct as *, caddr_t *, off_t,
    168 		    uint_t, uint_t, uint_t, cred_t *);
    169 struct vnode *specvp_devfs(struct vnode *, dev_t, vtype_t,
    170 		    struct cred *, dev_info_t *);
    171 void	spec_assoc_vp_with_devi(struct vnode *, dev_info_t *);
    172 dev_info_t *spec_hold_devi_by_vp(struct vnode *);
    173 int	spec_sync(struct vfs *, short, struct cred *);
    174 void	spec_snode_walk(int (*callback)(struct snode *, void *), void *);
    175 int	spec_devi_open_count(struct snode *, dev_info_t **);
    176 int	spec_is_clone(struct vnode *);
    177 int	spec_is_selfclone(struct vnode *);
    178 int	spec_fence_snode(dev_info_t *dip, struct vnode *vp);
    179 int	spec_unfence_snode(dev_info_t *dip);
    180 void	spec_size_invalidate(dev_t, vtype_t);
    181 
    182 
    183 /*
    184  * UNKNOWN_SIZE: If driver does not support the [Ss]ize or [Nn]blocks property
    185  * then the size is assumed to be "infinite".  Note that this "infinite" value
    186  * may need to be converted to a smaller "infinite" value to avoid EOVERFLOW at
    187  * field width conversion locations like the stat(2) and NFS code running
    188  * against a special file.  Special file code outside specfs may check the
    189  * type of the vnode (VCHR|VBLK) and use MAXOFFSET_T directly to detect
    190  * UNKNOWN_SIZE.
    191  */
    192 #define	UNKNOWN_SIZE		MAXOFFSET_T
    193 
    194 /*
    195  * SPEC_MAXOFFSET_T: Solaris does not fully support 64-bit offsets for D_64BIT
    196  * (SLOFFSET) block drivers on a 32-bit kernels: daddr_t is still a signed
    197  * 32-bit quantity - which limits the byte offset to 1TB. This issue goes
    198  * beyond a driver needing to convert from daddr_t to diskaddr_t if it sets
    199  * D_64BIT. Many of the DDI interfaces which take daddr_t arguments have no
    200  * 64-bit counterpart (bioclone, blkflush, bread, bread_common, breada, getblk,
    201  * getblk_common). SPEC_MAXOFFSET_T is used by 32-bit kernel code to enforce
    202  * this restriction.
    203  */
    204 #ifdef	_ILP32
    205 #ifdef	_LONGLONG_TYPE
    206 #define	SPEC_MAXOFFSET_T	((1LL << ((NBBY * sizeof (daddr32_t)) +	\
    207 				DEV_BSHIFT - 1)) - 1)
    208 #else	/* !defined(_LONGLONG_TYPE) */
    209 #define	SPEC_MAXOFFSET_T	MAXOFF_T
    210 #endif	/* _LONGLONG_TYPE */
    211 #endif	/* _ILP32 */
    212 
    213 /*
    214  * Snode lookup stuff.
    215  * These routines maintain a table of snodes hashed by dev so
    216  * that the snode for an dev can be found if it already exists.
    217  * NOTE: STABLESIZE must be a power of 2 for STABLEHASH to work!
    218  */
    219 
    220 #define	STABLESIZE	256
    221 #define	STABLEHASH(dev)	((getmajor(dev) + getminor(dev)) & (STABLESIZE - 1))
    222 extern struct snode *stable[];
    223 extern kmutex_t	stable_lock;
    224 extern kmutex_t	spec_syncbusy;
    225 
    226 /*
    227  * Variables used by during asynchronous VOP_PUTPAGE operations.
    228  */
    229 extern struct async_reqs *spec_async_reqs;	/* async request list */
    230 extern kmutex_t spec_async_lock;		/* lock to protect async list */
    231 
    232 #endif	/* _KERNEL */
    233 
    234 #ifdef	__cplusplus
    235 }
    236 #endif
    237 
    238 #endif	/* _SYS_FS_SNODE_H */
    239