192 lines
7 KiB
C
192 lines
7 KiB
C
/* fslib.c - routines needed by fs and fs utilities */
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#include <minix/config.h> /* for unused stuff in <minix/type.h> :-( */
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#include <minix/ansi.h>
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#include <limits.h>
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#include <dirent.h>
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#include <sys/types.h>
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#include <minix/const.h>
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#include <minix/type.h> /* for unshort :-( */
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#include "mfs/const.h" /* depends of -I flag in Makefile */
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#include "mfs/type.h" /* ditto */
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#include "mfs/inode.h" /* ditto */
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#include "mfs/super.h"
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#include <minix/fslib.h>
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/* The next routine is copied from fsck.c and mkfs.c... (Re)define some
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* things for consistency. Some things should be done better.
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*/
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/* Convert from bit count to a block count. The usual expression
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*
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* (nr_bits + (1 << BITMAPSHIFT) - 1) >> BITMAPSHIFT
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*
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* doesn't work because of overflow.
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*
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* Other overflow bugs, such as the expression for N_ILIST overflowing when
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* s_inodes is just over V*_INODES_PER_BLOCK less than the maximum+1, are not
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* fixed yet, because that number of inodes is silly.
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*/
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/* The above comment doesn't all apply now bit_t is long. Overflow is now
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* unlikely, but negative bit counts are now possible (though unlikely)
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* and give silly results.
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*/
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PUBLIC int bitmapsize(nr_bits, block_size)
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bit_t nr_bits;
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int block_size;
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{
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int nr_blocks;
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nr_blocks = (int) (nr_bits / FS_BITS_PER_BLOCK(block_size));
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if (((bit_t) nr_blocks * FS_BITS_PER_BLOCK(block_size)) < nr_bits) ++nr_blocks;
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return(nr_blocks);
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}
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/*===========================================================================*
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* conv2 *
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*===========================================================================*/
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PUBLIC unsigned conv2(norm, w)
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int norm; /* TRUE if no swap, FALSE for byte swap */
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int w; /* promotion of 16-bit word to be swapped */
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{
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/* Possibly swap a 16-bit word between 8086 and 68000 byte order. */
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if (norm) return( (unsigned) w & 0xFFFF);
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return( ((w&BYTE) << 8) | ( (w>>8) & BYTE));
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}
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/*===========================================================================*
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* conv4 *
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*===========================================================================*/
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PUBLIC long conv4(norm, x)
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int norm; /* TRUE if no swap, FALSE for byte swap */
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long x; /* 32-bit long to be byte swapped */
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{
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/* Possibly swap a 32-bit long between 8086 and 68000 byte order. */
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unsigned lo, hi;
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long l;
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if (norm) return(x); /* byte order was already ok */
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lo = conv2(FALSE, (int) x & 0xFFFF); /* low-order half, byte swapped */
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hi = conv2(FALSE, (int) (x>>16) & 0xFFFF); /* high-order half, swapped */
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l = ( (long) lo <<16) | hi;
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return(l);
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}
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/*===========================================================================*
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* conv_inode *
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*===========================================================================*/
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PUBLIC void conv_inode(rip, dip, dip2, rw_flag, magic)
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register struct inode *rip; /* pointer to the in-core inode struct */
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register d1_inode *dip; /* pointer to the V1 on-disk inode struct */
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register d2_inode *dip2; /* pointer to the V2 on-disk inode struct */
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int rw_flag; /* READING or WRITING */
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int magic; /* magic number of file system */
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{
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/* Copy the inode from the disk block to the in-core table or vice versa.
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* If the fourth parameter below is FALSE, the bytes are swapped.
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*/
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switch (magic) {
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case SUPER_MAGIC: old_icopy(rip, dip, rw_flag, TRUE); break;
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case SUPER_REV: old_icopy(rip, dip, rw_flag, FALSE); break;
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case SUPER_V3:
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case SUPER_V2: new_icopy(rip, dip2, rw_flag, TRUE); break;
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case SUPER_V2_REV: new_icopy(rip, dip2, rw_flag, FALSE); break;
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}
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}
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/*===========================================================================*
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* old_icopy *
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*===========================================================================*/
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PUBLIC void old_icopy(rip, dip, direction, norm)
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register struct inode *rip; /* pointer to the in-core inode struct */
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register d1_inode *dip; /* pointer to the d1_inode inode struct */
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int direction; /* READING (from disk) or WRITING (to disk) */
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int norm; /* TRUE = do not swap bytes; FALSE = swap */
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{
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/* 4 different on-disk inode layouts are supported, one for each combination
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* of V1.x/V2.x * bytes-swapped/not-swapped. When an inode is read or written
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* this routine handles the conversions so that the information in the inode
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* table is independent of the disk structure from which the inode came.
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* The old_icopy routine copies to and from V1 disks.
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*/
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int i;
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if (direction == READING) {
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/* Copy V1.x inode to the in-core table, swapping bytes if need be. */
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rip->i_mode = conv2(norm, dip->d1_mode);
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rip->i_uid = conv2(norm,dip->d1_uid );
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rip->i_size = conv4(norm,dip->d1_size);
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rip->i_mtime = conv4(norm,dip->d1_mtime);
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rip->i_atime = 0;
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rip->i_ctime = 0;
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rip->i_nlinks = (nlink_t) dip->d1_nlinks; /* 1 char */
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rip->i_gid = (gid_t) dip->d1_gid; /* 1 char */
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rip->i_ndzones = V1_NR_DZONES;
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rip->i_nindirs = V1_INDIRECTS;
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for (i = 0; i < V1_NR_TZONES; i++)
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rip->i_zone[i] = conv2(norm, (int) dip->d1_zone[i]);
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} else {
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/* Copying V1.x inode to disk from the in-core table. */
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dip->d1_mode = conv2(norm,rip->i_mode);
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dip->d1_uid = conv2(norm,rip->i_uid );
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dip->d1_size = conv4(norm,rip->i_size);
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dip->d1_mtime = conv4(norm,rip->i_mtime);
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dip->d1_nlinks = (nlink_t) rip->i_nlinks; /* 1 char */
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dip->d1_gid = (gid_t) rip->i_gid; /* 1 char */
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for (i = 0; i < V1_NR_TZONES; i++)
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dip->d1_zone[i] = conv2(norm, (int) rip->i_zone[i]);
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}
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}
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/*===========================================================================*
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* new_icopy *
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*===========================================================================*/
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PUBLIC void new_icopy(rip, dip, direction, norm)
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register struct inode *rip; /* pointer to the in-core inode struct */
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register d2_inode *dip; /* pointer to the d2_inode struct */
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int direction; /* READING (from disk) or WRITING (to disk) */
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int norm; /* TRUE = do not swap bytes; FALSE = swap */
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{
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/* Same as old_icopy, but to/from V2 disk layout. */
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int i;
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if (direction == READING) {
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/* Copy V2.x inode to the in-core table, swapping bytes if need be. */
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rip->i_mode = conv2(norm,dip->d2_mode);
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rip->i_uid = conv4(norm,dip->d2_uid );
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rip->i_nlinks = conv2(norm,(int) dip->d2_nlinks);
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rip->i_gid = conv4(norm,(int) dip->d2_gid );
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rip->i_size = conv4(norm,dip->d2_size);
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rip->i_atime = conv4(norm,dip->d2_atime);
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rip->i_ctime = conv4(norm,dip->d2_ctime);
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rip->i_mtime = conv4(norm,dip->d2_mtime);
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rip->i_ndzones = V2_NR_DZONES;
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rip->i_nindirs = V2_INDIRECTS(rip->i_sp->s_block_size);
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for (i = 0; i < V2_NR_TZONES; i++)
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rip->i_zone[i] = conv4(norm, (long) dip->d2_zone[i]);
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} else {
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/* Copying V2.x inode to disk from the in-core table. */
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dip->d2_mode = conv2(norm,rip->i_mode);
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dip->d2_uid = conv4(norm,rip->i_uid );
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dip->d2_nlinks = conv2(norm,rip->i_nlinks);
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dip->d2_gid = conv4(norm,rip->i_gid );
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dip->d2_size = conv4(norm,rip->i_size);
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dip->d2_atime = conv4(norm,rip->i_atime);
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dip->d2_ctime = conv4(norm,rip->i_ctime);
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dip->d2_mtime = conv4(norm,rip->i_mtime);
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for (i = 0; i < V2_NR_TZONES; i++)
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dip->d2_zone[i] = conv4(norm, (long) rip->i_zone[i]);
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}
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}
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