/*
 * Written by Paul Popelka (paulp@uts.amdahl.com)
 * 
 * You can do anything you want with this software, just don't say you wrote
 * it, and don't remove this notice.
 * 
 * This software is provided "as is".
 * 
 * The author supplies this software to be publicly redistributed on the
 * understanding that the author is not responsible for the correct
 * functioning of this software in any circumstances and is not liable for
 * any damages caused by this software.
 * 
 * October 1992
 * 
 *	$Id: denode.h,v 1.1 1993/08/13 11:35:31 cgd Exp $
 */

/*
 * This is the pc filesystem specific portion of the vnode structure. To
 * describe a file uniquely the de_dirclust, de_diroffset, and
 * de_de.deStartCluster fields are used.  de_dirclust contains the cluster
 * number of the directory cluster containing the entry for a file or
 * directory.  de_diroffset is the index into the cluster for the entry
 * describing a file or directory.  de_de.deStartCluster is the number of
 * the first cluster of the file or directory.  Now to describe the quirks
 * of the pc filesystem. - Clusters 0 and 1 are reserved. - The first
 * allocatable cluster is 2. - The root directory is of fixed size and all
 * blocks that make it up are contiguous. - Cluster 0 refers to the root
 * directory when it is found in the startcluster field of a directory
 * entry that points to another directory. - Cluster 0 implies a 0 length
 * file when found in the start cluster field of a directory entry that
 * points to a file. - You can't use the cluster number 0 to derive the
 * address of the root directory. - Multiple directory entries can point to
 * a directory. The entry in the parent directory points to a child
 * directory.  Any directories in the child directory contain a ".." entry
 * that points back to the child.  The child directory itself contains a
 * "." entry that points to itself. - The root directory does not contain a
 * "." or ".." entry. - Directory entries for directories are never changed
 * once they are created (except when removed).  The size stays 0, and the
 * last modification time is never changed.  This is because so many
 * directory entries can point to the physical clusters that make up a
 * directory.  It would lead to an update nightmare. - The length field in
 * a directory entry pointing to a directory contains 0 (always).  The only
 * way to find the end of a directory is to follow the cluster chain until
 * the "last cluster" marker is found. My extensions to make this house of
 * cards work.  These apply only to the in memory copy of the directory
 * entry. - A reference count for each denode will be kept since dos
 * doesn't keep such things.
 */

/*
 * Internal pseudo-offset for (nonexistent) directory entry for the root
 * dir in the root dir
 */
#define	MSDOSFSROOT_OFS	0x1fffffff

/*
 * The fat cache structure. fc_fsrcn is the filesystem relative cluster
 * number that corresponds to the file relative cluster number in this
 * structure (fc_frcn).
 */
struct fatcache {
	u_short fc_frcn;	/* file relative cluster number */
	u_short fc_fsrcn;	/* filesystem relative cluster number */
};

/*
 * The fat entry cache as it stands helps make extending files a "quick"
 * operation by avoiding having to scan the fat to discover the last
 * cluster of the file. The cache also helps sequential reads by
 * remembering the last cluster read from the file.  This also prevents us
 * from having to rescan the fat to find the next cluster to read.  This
 * cache is probably pretty worthless if a file is opened by multiple
 * processes.
 */
#define	FC_SIZE		2	/* number of entries in the cache */
#define	FC_LASTMAP	0	/* entry the last call to pcbmap() resolved
				 * to */
#define	FC_LASTFC	1	/* entry for the last cluster in the file */

#define	FCE_EMPTY	0xffff	/* doesn't represent an actual cluster # */

/*
 * Set a slot in the fat cache.
 */
#define	fc_setcache(dep, slot, frcn, fsrcn) \
	(dep)->de_fc[slot].fc_frcn = frcn; \
	(dep)->de_fc[slot].fc_fsrcn = fsrcn;

/*
 * This is the in memory variant of a dos directory entry.  It is usually
 * contained within a vnode.
 */
struct denode {
	struct denode *de_chain[2];	/* hash chain ptrs */
	struct vnode *de_vnode;	/* addr of vnode we are part of */
	struct vnode *de_devvp;	/* vnode of blk dev we live on */
	u_long de_flag;		/* flag bits */
	dev_t de_dev;		/* device where direntry lives */
	u_long de_dirclust;	/* cluster of the directory file containing this entry */
	u_long de_diroffset;	/* ordinal of this entry in the directory */
	long de_refcnt;		/* reference count */
	struct msdosfsmount *de_pmp;	/* addr of our mount struct */
	struct lockf *de_lockf;	/* byte level lock list */
	long de_spare0;		/* current lock holder */
	long de_spare1;		/* lock wanter */
	struct direntry de_de;	/* the actual directory entry */
	struct fatcache de_fc[FC_SIZE];	/* fat cache */
};

/*
 * Values for the de_flag field of the denode.
 */
#define	DELOCKED	0x0001	/* directory entry is locked */
#define	DEWANT		0x0002	/* someone wants this de */
#define	DERENAME	0x0004	/* de is being renamed */
#define	DEUPD		0x0008	/* file has been modified */
#define	DESHLOCK	0x0010	/* file has shared lock */
#define	DEEXLOCK	0x0020	/* file has exclusive lock */
#define	DELWAIT		0x0040	/* someone waiting on file lock */
#define	DEMOD		0x0080	/* denode wants to be written back to disk */

/*
 * Shorthand macros used to reference fields in the direntry contained in
 * the denode structure.
 */
#define	de_Name		de_de.deName
#define	de_Extension	de_de.deExtension
#define	de_Attributes	de_de.deAttributes
#define	de_Reserved	de_de.deReserved
#define	de_Time		de_de.deTime
#define	de_Date		de_de.deDate
#define	de_StartCluster	de_de.deStartCluster
#define	de_FileSize	de_de.deFileSize
#define	de_forw		de_chain[0]
#define	de_back		de_chain[1]

#if defined(KERNEL)

#define	VTODE(vp)	((struct denode *)(vp)->v_data)
#define	DETOV(de)	((de)->de_vnode)

#define	DELOCK(de)	delock(de)
#define	DEUNLOCK(de)	deunlock(de)

#define	DEUPDAT(dep, t, waitfor) \
	if (dep->de_flag & DEUPD) \
		(void) deupdat(dep, t, waitfor);

#define	DETIMES(dep, t) \
	if (dep->de_flag & DEUPD) { \
		(dep)->de_flag |= DEMOD; \
		unix2dostime(t, (union dosdate *)&dep->de_Date, \
			(union dostime *)&dep->de_Time); \
		(dep)->de_flag &= ~DEUPD; \
	}

/*
 * This overlays the fid sturcture (see mount.h)
 */
struct defid {
	u_short defid_len;	/* length of structure */
	u_short defid_pad;	/* force long alignment */

	u_long defid_dirclust;	/* cluster this dir entry came from */
	u_long defid_dirofs;	/* index of entry within the cluster */

	/* u_long	defid_gen;	/* generation number */
};

/*
 * Prototypes for MSDOSFS vnode operations
 */
int msdosfs_lookup __P((struct vnode * vp, struct nameidata * ndp, struct proc * p));
int msdosfs_create __P((struct nameidata * ndp, struct vattr * vap, struct proc * p));
int msdosfs_mknod __P((struct nameidata * ndp, struct vattr * vap, struct ucred * cred, struct proc * p));
int msdosfs_open __P((struct vnode * vp, int mode, struct ucred * cred, struct proc * p));
int msdosfs_close __P((struct vnode * vp, int fflag, struct ucred * cred, struct proc * p));
int msdosfs_access __P((struct vnode * vp, int mode, struct ucred * cred, struct proc * p));
int msdosfs_getattr __P((struct vnode * vp, struct vattr * vap, struct ucred * cred, struct proc * p));
int msdosfs_setattr __P((struct vnode * vp, struct vattr * vap, struct ucred * cred, struct proc * p));
int msdosfs_read __P((struct vnode * vp, struct uio * uio, int ioflag, struct ucred * cred));
int msdosfs_write __P((struct vnode * vp, struct uio * uio, int ioflag, struct ucred * cred));
int msdosfs_ioctl __P((struct vnode * vp, int command, caddr_t data, int fflag, struct ucred * cred, struct proc * p));
int msdosfs_select __P((struct vnode * vp, int which, int fflags, struct ucred * cred, struct proc * p));
int msdosfs_mmap __P((struct vnode * vp, int fflags, struct ucred * cred, struct proc * p));
int msdosfs_fsync __P((struct vnode * vp, int fflags, struct ucred * cred, int waitfor, struct proc * p));
int msdosfs_seek __P((struct vnode * vp, off_t oldoff, off_t newoff, struct ucred * cred));
int msdosfs_remove __P((struct nameidata * ndp, struct proc * p));
int msdosfs_link __P((struct vnode * vp, struct nameidata * ndp, struct proc * p));
int msdosfs_rename __P((struct nameidata * fndp, struct nameidata * tdnp, struct proc * p));
int msdosfs_mkdir __P((struct nameidata * ndp, struct vattr * vap, struct proc * p));
int msdosfs_rmdir __P((struct nameidata * ndp, struct proc * p));
int msdosfs_symlink __P((struct nameidata * ndp, struct vattr * vap, char *target, struct proc * p));
#ifdef __bsdi__
int msdosfs_readdir __P((struct vnode * vp, struct uio * uio, struct ucred * cred, int *eofflagp, u_int * cookies, int ncookies));
#else
int msdosfs_readdir __P((struct vnode * vp, struct uio * uio, struct ucred * cred, int *eofflagp));
#endif
int msdosfs_readlink __P((struct vnode * vp, struct uio * uio, struct ucred * cred));
int msdosfs_abortop __P((struct nameidata * ndp));
int msdosfs_inactive __P((struct vnode * vp, struct proc * p));
int msdosfs_reclaim __P((struct vnode * vp));
int msdosfs_lock __P((struct vnode * vp));
int msdosfs_unlock __P((struct vnode * vp));
int msdosfs_bmap __P((struct vnode * vp, daddr_t bn, struct vnode ** vpp, daddr_t * bnp));
int msdosfs_strategy __P((struct buf * bp));
int msdosfs_print __P((struct vnode * vp));
int msdosfs_islocked __P((struct vnode * vp));
int msdosfs_advlock __P((struct vnode * vp, caddr_t id, int op, struct flock * fl, int flags));

/*
 * Internal service routine prototypes.
 */
int deget __P((struct msdosfsmount * pmp, u_long dirclust, u_long diroffset, struct direntry * direntptr, struct denode ** depp));

#endif				/* defined(KERNEL) */