usr/src/sys/ufs/ffs/lockf.h

/*
 * Copyright (c) 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Scooter Morris at Genentech Inc.
 *
 * %sccs.include.redist.c%
 *
 *      @(#)lockf.h     7.1 (Berkeley) %G%
 */

/*
 * The lockf structure is a kernel structure which contains all the
 * information associated with a byte range lock. The lockf structures
 * are linked into the inode structure. Locks are sorted by the starting
 * byte of the lock for efficiency.
 */
struct lockf {
        short   lf_flags;        /* Lock semantics: F_POSIX, F_FLOCK, F_WAIT */
        short   lf_type;         /* Lock type: F_RDLCK, F_WRLCK */
        off_t   lf_start;        /* The byte # of the start of the lock */
        off_t   lf_end;          /* The byte # of the end of the lock (-1=EOF)*/
        caddr_t lf_id;           /* The id of the resource holding the lock */
        struct  inode *lf_inode; /* Back pointer to the inode */
        struct  lockf *lf_next;  /* A pointer to the next lock on this inode */
        struct  lockf *lf_block; /* The list of blocked locks */
};

/*
 * Maximum length of sleep chains to traverse to try and detect deadlock.
 */
#define MAXDEPTH 50

#ifdef  KERNEL
/*
 * Public lock manipulation routines
 */
extern struct lockf *lf_remove();       /* Remove a lock */
extern struct lockf *lf_getblock();     /* Return the first blocking lock */

#ifdef  LOCKF_DEBUG
extern int lockf_debug;
#endif  LOCKF_DEBUG
#endif  KERNEL