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This mod adds a number of optimizations to increase the
performance of xfsdump and xfsrestore, especially on filesystems
with millions of inodes. Many small changes were made to
minimize the number of system calls required per inode.
Significant changes to xfsdump:
- Cache the gen number of each inode during the initial inode
  scan so that a bulkstat single does not need to be done for
  each inode when dumping directories.
- No longer retrieve the DMF attribute when estimating the dump
  size of a file. Use information from the bulkstat instead.
- Retrieve DMF attribute by handle instead of doing
  open/attr_getf/close.
- In determining where to split multi-stream dumps, take into
  consideration the number of files and not just the file size.
  This allows filesystems with large amounts of inodes but
  relatively little data (DMF filesystem) to be split correctly.
Significant changes to xfsrestore:
- Buffer writes to the namreg file to eliminate 2 very small
  write system calls per directory entry.
- Buffer writes to dirattr file to eliminate a small write system
  call per directory.
- Speedup the check to see if a particular window of the tree
  file is mapped. This allows xfsrestore to use more, smaller
  windows which is beneficial if we can't fit them all in memory
  and have to start unmapping them. This also makes the -w
  option obsolete so that option now has no effect.
- Change the hash function to give a better distribution among
  the hash buckets.
- Do not make an unnecessary unlink call if the file being
  restored does not already exist.

/*
 * 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 UTIL_H
#define UTIL_H


/* util.[hc] - generally useful functions
 */

/* write_buf - converts the normal manager write method into something simpler
 *
 * the managers present a somewhat complicated write interface, for performance
 * reasons, which eliminates buffer copying. however, there are times when
 * the data to be written is already buffered, such as when writing out
 * header structures. This function takes care of the details of writing
 * the contents of such a buffer using the manager operators.
 *
 * if bufp is null, writes bufsz zeros.
 */
typedef char * ( * gwbfp_t )( void *contextp, size_t wantedsz, size_t *szp);
typedef intgen_t ( * wfp_t )( void *contextp, char *bufp, size_t bufsz );

extern intgen_t write_buf( char *bufp,
			   size_t bufsz,
			   void *contextp,
			   gwbfp_t get_write_buf_funcp,
			   wfp_t write_funcp );


/* read_buf - converts the normal manager read method into something simpler
 *
 * the managers present a somewhat complicated read interface, for performance
 * reasons, which eliminates buffer copying. however, there are times when
 * the caller wants his buffer to be filled  completely, such as when reading
 * header structures. This function takes care of the details of filling
 * such a buffer using the manager operators.
 *
 * if bufp is null, discards read data.
 *
 * returns number of bytes successfully read. returns by reference the
 * status of the first failure of the read funcp. if no read failures occur,
 * *statp will be zero.
 */
typedef char * ( *rfp_t )( void *contextp, size_t wantedsz, size_t *szp, intgen_t *statp );
typedef void ( * rrbfp_t )( void *contextp, char *bufp, size_t bufsz );

extern intgen_t read_buf( char *bufp,
			  size_t bufsz, 
			  void *contextp,
			  rfp_t read_funcp,
			  rrbfp_t return_read_buf_funcp,
			  intgen_t *statp );


#define min( a, b )	( ( ( a ) < ( b ) ) ? ( a ) : ( b ) )
#define max( a, b )	( ( ( a ) > ( b ) ) ? ( a ) : ( b ) )


/* strncpyterm - like strncpy, but guarantees the destination is null-terminated
 */
extern char *strncpyterm( char *s1, char *s2, size_t n );

/* bigstat - efficient file status gatherer. presents an iterative
 * callback interface, invoking the caller's callback for each in-use
 * inode. the caller can specify the first ino, and can limit the callbacks
 * to just dirs, just non-dirs, or both. if the callback returns non-zero,
 * aborts the iteration and sets stat to the callback's return; otherwise,
 * stat is set to zero. return value set to errno if the system call fails,
 * or EINTR if optional pre-emption func returns TRUE.
 */
#define BIGSTAT_ITER_DIR	( 1 << 0 )
#define BIGSTAT_ITER_NONDIR	( 1 << 1 )
#define BIGSTAT_ITER_ALL	( ~0 )

extern intgen_t bigstat_iter( jdm_fshandle_t *fshandlep,
			      intgen_t fsid,
			      intgen_t selector,
			      xfs_ino_t start_ino,
			      intgen_t ( * fp )( void *arg1,
						 jdm_fshandle_t *fshandlep,
						 intgen_t fsfd,
						 xfs_bstat_t *statp ),
			      void * arg1,
			      intgen_t *statp,
			      bool_t ( pfp )( int ), /* preemption chk func */
			      xfs_bstat_t *buf,
			      size_t buflen );

extern intgen_t bigstat_one( intgen_t fsid,
			     xfs_ino_t ino,
			     xfs_bstat_t *statp );

/* efficiently count the number of 64-inode groups. */
extern intgen_t inogrp_count( intgen_t fsfd,
			      intgen_t *grpcnt );


/* calls the callback for every entry in the directory specified
 * by the stat buffer. supplies the callback with a file system
 * handler and a stat buffer, and the name from the dirent.
 *
 * NOTE: does NOT invoke callback for "." or ".."!
 *
 * caller may supply getdents buffer. size must be >= sizeof( dirent_t )
 * + MAXPATHLEN. if not supplied (usrgdp NULL), one will be malloc()ed.
 *
 * if the callback returns non-zero, returns 1 with cbrval set to the
 * callback's return value. if syscall fails, returns -1 with errno set.
 * otherwise returns 0.
 */
extern intgen_t diriter( jdm_fshandle_t *fshandlep,
			 intgen_t fsfd,
			 xfs_bstat_t *statp,
			 intgen_t ( *cbfp )( void *arg1,
					     jdm_fshandle_t *fshandlep,
					     intgen_t fsfd,
					     xfs_bstat_t *statp,
					     char *namep ),
			 void *arg1,
			 intgen_t *cbrvalp,
			 char *usrgdp,
			 size_t usrgdsz );



/* ctimennl - ctime(3C) with newline removed
 */
extern char *ctimennl( const time32_t *clockp );

/* ctime32 - takes a time32_t instead of a time_t
 */
extern char *ctime32( const time32_t *timep );



/* fold_t - a character string made to look like a "fold here"
 */
#define FOLD_LEN	79
typedef char fold_t[ FOLD_LEN + 1 ];
extern void fold_init( fold_t fold, char *infostr, char c );


/* macro to copy uuid structures
 */
#define COPY_LABEL( lab1, lab2) ( bcopy( lab1, lab2, GLOBAL_HDR_STRING_SZ) )

/* flg definitions for preemptchk 
 */
#define PREEMPT_FULL		0
#define PREEMPT_PROGRESSONLY	1

/*
 * Align pointer up to alignment
 */
#define	ALIGN_PTR(p,a)	\
	(((__psint_t)(p) & ((a)-1)) ? \
		((void *)(((__psint_t)(p) + ((a)-1)) & ~((a)-1))) : \
		((void *)(p)))

#endif /* UTIL_H */