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The inomap was implemented to all efficient lookups in
increasing ino order. This doesn't work well for dealing
with subtrees, since recursing through subtrees will
result in processing inodes in non-increasing ino order.
Change the inomap lookup routines to use binary search,
and use a cursor to remember where the previous search
ended. This allows fast lookups for random lookups, and
keeps sequential lookups fast as well.

/*
 * Copyright (c) 2000-2001 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#ifndef INOMAP_H
#define INOMAP_H

/* inomap.[hc] - inode map abstraction
 *
 * an inode map describes the inode numbers (inos) in a file system dump.
 * the map identifies which inos are in-use by the fs, which of those are
 * directories, and which are dumped.
 *
 * the map is represented as a list of map segments. a map segment is
 * a 64-bit starting ino and two 64-bit bitmaps. the bitmaps describe
 * the 64 inos beginning with the starting ino. two bits are available
 * for each ino.
 */

/* inomap_build - this function allocates and constructs an in-memory
 * representation of the bitmap. it prunes from the map inos of files not
 * changed since the last dump, inos not identified by the subtree list,
 * and directories not needed to represent a hierarchy containing
 * changed inodes. it handles hard links; a file linked to multiple
 * directory entries will not be pruned if at least one of those
 * directories has an ancestor in the subtree list.
 *
 * it returns by reference an array of startpoints in the non-directory
 * portion of the dump, as well as the count of dir and nondir inos
 * makred as present and to be dumped. A startpoint identifies a non-dir ino,
 * and a non-hole accumulated size position within that file. only very large
 * files will contain a startpoint; in all other cases the startpoints will
 * fall at file boundaries. returns BOOL_FALSE if error encountered (should
 * abort the dump; else returns BOOL_TRUE.
 */
extern bool_t inomap_build( jdm_fshandle_t *fshandlep,
			    intgen_t fsfd,
			    xfs_bstat_t *rootstatp,
			    bool_t last,
	      		    time32_t lasttime,
			    bool_t resume,
	      		    time32_t resumetime,
			    size_t resumerangecnt,
			    drange_t *resumerangep,
			    char *subtreebuf[],
			    ix_t subtreecnt,
			    startpt_t startptp[],
	      		    size_t startptcnt,
			    ix_t *statphasep,
			    ix_t *statpassp,
			    size64_t statcnt,
			    size64_t *statdonep );

#ifdef SIZEEST
extern u_int64_t inomap_getsz( void );
#endif /* SIZEEST */

/* inomap_skip - tell inomap about inodes to skip in the dump
 */
extern void inomap_skip( xfs_ino_t ino );


/* inomap_writehdr - updates the write header with inomap-private info
 * to be communicated to the restore side
 */
extern void inomap_writehdr( content_inode_hdr_t *scwhdrp );


/* inomap_dump - dumps the map to media - content-abstraction-knowledgable
 *
 * returns error from media write op
 */
extern rv_t inomap_dump( drive_t *drivep );


/* map state values
 */
#define MAP_INO_UNUSED	0       /* ino not in use by fs */
#define MAP_DIR_NOCHNG	1       /* dir, ino in use by fs, but not dumped */
#define MAP_NDR_NOCHNG	2       /* non-dir, ino in use by fs, but not dumped */
#define MAP_DIR_CHANGE	3       /* dir, changed since last dump */
#define MAP_NDR_CHANGE	4       /* non-dir, changed since last dump */
#define MAP_DIR_SUPPRT	5       /* dir, unchanged but needed for hierarchy */
#define MAP_RESERVED1	6       /* this state currently not used */
#define MAP_RESERVED2	7       /* this state currently not used */

/* the inomap is implemented as a linked list of chunks. each chunk contains
 * an array of map segments. a map segment contains a start ino and a
 * bitmap of 64 3-bit state values (see MAP_... in inomap.h). the SEG_macros
 * index and manipulate the 3-bit state values.
 */
struct seg {
	xfs_ino_t base;
	u_int64_t lobits;
	u_int64_t mebits;
	u_int64_t hibits;
};

typedef struct seg seg_t;

#define INOPERSEG	( sizeof( (( seg_t * )0 )->lobits ) * NBBY )

#define HNKSZ		( 4 * PGSZ )
#define SEGPERHNK	( ( HNKSZ / sizeof( seg_t )) - 1 )

struct hnk {
	seg_t seg[ SEGPERHNK ];
	xfs_ino_t maxino;
	struct hnk *nextp;		/* no longer used, kept for binary compat */
	char pad[sizeof( seg_t ) - sizeof( xfs_ino_t ) - sizeof( struct hnk * )];
};

typedef struct hnk hnk_t;

/* functions to get state and gen information from the inomap.
 * requires a pointer to a context block, obtained from
 * inomap_alloc_context(), and released by inomap_free_context().
 */
extern void *inomap_alloc_context( void );
extern void inomap_free_context( void *contextp );
extern intgen_t inomap_get_state( void *contextp, xfs_ino_t ino );
extern gen_t inomap_get_gen( void *contextp, xfs_ino_t ino );

#ifdef NOTUSED
/* inomap_iter_cb - will call the supplied function for each ino in
 * the map matching a state in the state mask. if the callback returns
 * FALSE, the iteration will be aborted and inomap_iter_cb() will
 * return FALSE. the state mask is constructed by OR'ing bits in bit
 * positions corresponding to the state values.
 */
extern bool_t inomap_iter_cb( void *contextp,
			      intgen_t statemask,
			      bool_t ( *funcp )( void *contextp,
					         xfs_ino_t ino,
					         intgen_t state ));
#endif /* NOTUSED */

#endif /* INOMAP_H */