| 1 | /* fslib.c - routines needed by fs and fs utilities */
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| 2 |
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| 3 | #include <minix/config.h> /* for unused stuff in <minix/type.h> :-( */
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| 4 | #include <ansi.h>
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| 5 | #include <limits.h>
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| 6 | #include <dirent.h>
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| 7 | #include <sys/types.h>
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| 8 | #include <minix/const.h>
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| 9 | #include <minix/type.h> /* for unshort :-( */
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| 10 | #include "fs/const.h" /* depends of -I flag in Makefile */
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| 11 | #include "fs/type.h" /* ditto */
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| 12 | #include "fs/inode.h" /* ditto */
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| 13 | #include "fs/super.h"
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| 14 | #include <minix/fslib.h>
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| 15 |
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| 16 | /* The next routine is copied from fsck.c and mkfs.c... (Re)define some
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| 17 | * things for consistency. Some things should be done better.
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| 18 | */
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| 19 |
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| 20 | /* Convert from bit count to a block count. The usual expression
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| 21 | *
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| 22 | * (nr_bits + (1 << BITMAPSHIFT) - 1) >> BITMAPSHIFT
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| 23 | *
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| 24 | * doesn't work because of overflow.
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| 25 | *
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| 26 | * Other overflow bugs, such as the expression for N_ILIST overflowing when
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| 27 | * s_inodes is just over V*_INODES_PER_BLOCK less than the maximum+1, are not
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| 28 | * fixed yet, because that number of inodes is silly.
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| 29 | */
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| 30 | /* The above comment doesn't all apply now bit_t is long. Overflow is now
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| 31 | * unlikely, but negative bit counts are now possible (though unlikely)
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| 32 | * and give silly results.
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| 33 | */
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| 34 | PUBLIC int bitmapsize(nr_bits, block_size)
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| 35 | bit_t nr_bits;
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| 36 | int block_size;
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| 37 | {
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| 38 | int nr_blocks;
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| 39 |
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| 40 | nr_blocks = (int) (nr_bits / FS_BITS_PER_BLOCK(block_size));
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| 41 | if (((bit_t) nr_blocks * FS_BITS_PER_BLOCK(block_size)) < nr_bits) ++nr_blocks;
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| 42 | return(nr_blocks);
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| 43 | }
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| 44 |
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| 45 |
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| 46 | /*===========================================================================*
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| 47 | * conv2 *
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| 48 | *===========================================================================*/
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| 49 | PUBLIC unsigned conv2(norm, w)
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| 50 | int norm; /* TRUE if no swap, FALSE for byte swap */
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| 51 | int w; /* promotion of 16-bit word to be swapped */
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| 52 | {
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| 53 | /* Possibly swap a 16-bit word between 8086 and 68000 byte order. */
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| 54 |
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| 55 | if (norm) return( (unsigned) w & 0xFFFF);
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| 56 | return( ((w&BYTE) << 8) | ( (w>>8) & BYTE));
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| 57 | }
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| 58 |
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| 59 |
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| 60 | /*===========================================================================*
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| 61 | * conv4 *
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| 62 | *===========================================================================*/
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| 63 | PUBLIC long conv4(norm, x)
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| 64 | int norm; /* TRUE if no swap, FALSE for byte swap */
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| 65 | long x; /* 32-bit long to be byte swapped */
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| 66 | {
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| 67 | /* Possibly swap a 32-bit long between 8086 and 68000 byte order. */
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| 68 |
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| 69 | unsigned lo, hi;
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| 70 | long l;
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| 71 |
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| 72 | if (norm) return(x); /* byte order was already ok */
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| 73 | lo = conv2(FALSE, (int) x & 0xFFFF); /* low-order half, byte swapped */
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| 74 | hi = conv2(FALSE, (int) (x>>16) & 0xFFFF); /* high-order half, swapped */
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| 75 | l = ( (long) lo <<16) | hi;
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| 76 | return(l);
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| 77 | }
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| 78 |
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| 79 |
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| 80 | /*===========================================================================*
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| 81 | * conv_inode *
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| 82 | *===========================================================================*/
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| 83 | PUBLIC void conv_inode(rip, dip, dip2, rw_flag, magic)
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| 84 | register struct inode *rip; /* pointer to the in-core inode struct */
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| 85 | register d1_inode *dip; /* pointer to the V1 on-disk inode struct */
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| 86 | register d2_inode *dip2; /* pointer to the V2 on-disk inode struct */
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| 87 | int rw_flag; /* READING or WRITING */
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| 88 | int magic; /* magic number of file system */
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| 89 | {
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| 90 | /* Copy the inode from the disk block to the in-core table or vice versa.
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| 91 | * If the fourth parameter below is FALSE, the bytes are swapped.
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| 92 | */
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| 93 | switch (magic) {
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| 94 | case SUPER_MAGIC: old_icopy(rip, dip, rw_flag, TRUE); break;
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| 95 | case SUPER_REV: old_icopy(rip, dip, rw_flag, FALSE); break;
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| 96 | case SUPER_V3:
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| 97 | case SUPER_V2: new_icopy(rip, dip2, rw_flag, TRUE); break;
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| 98 | case SUPER_V2_REV: new_icopy(rip, dip2, rw_flag, FALSE); break;
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| 99 | }
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| 100 | }
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| 101 |
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| 102 |
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| 103 | /*===========================================================================*
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| 104 | * old_icopy *
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| 105 | *===========================================================================*/
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| 106 | PUBLIC void old_icopy(rip, dip, direction, norm)
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| 107 | register struct inode *rip; /* pointer to the in-core inode struct */
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| 108 | register d1_inode *dip; /* pointer to the d1_inode inode struct */
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| 109 | int direction; /* READING (from disk) or WRITING (to disk) */
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| 110 | int norm; /* TRUE = do not swap bytes; FALSE = swap */
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| 111 |
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| 112 | {
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| 113 | /* 4 different on-disk inode layouts are supported, one for each combination
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| 114 | * of V1.x/V2.x * bytes-swapped/not-swapped. When an inode is read or written
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| 115 | * this routine handles the conversions so that the information in the inode
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| 116 | * table is independent of the disk structure from which the inode came.
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| 117 | * The old_icopy routine copies to and from V1 disks.
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| 118 | */
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| 119 |
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| 120 | int i;
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| 121 |
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| 122 | if (direction == READING) {
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| 123 | /* Copy V1.x inode to the in-core table, swapping bytes if need be. */
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| 124 | rip->i_mode = conv2(norm, dip->d1_mode);
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| 125 | rip->i_uid = conv2(norm,dip->d1_uid );
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| 126 | rip->i_size = conv4(norm,dip->d1_size);
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| 127 | rip->i_mtime = conv4(norm,dip->d1_mtime);
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| 128 | rip->i_atime = 0;
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| 129 | rip->i_ctime = 0;
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| 130 | rip->i_nlinks = (nlink_t) dip->d1_nlinks; /* 1 char */
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| 131 | rip->i_gid = (gid_t) dip->d1_gid; /* 1 char */
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| 132 | rip->i_ndzones = V1_NR_DZONES;
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| 133 | rip->i_nindirs = V1_INDIRECTS;
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| 134 | for (i = 0; i < V1_NR_TZONES; i++)
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| 135 | rip->i_zone[i] = conv2(norm, (int) dip->d1_zone[i]);
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| 136 | } else {
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| 137 | /* Copying V1.x inode to disk from the in-core table. */
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| 138 | dip->d1_mode = conv2(norm,rip->i_mode);
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| 139 | dip->d1_uid = conv2(norm,rip->i_uid );
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| 140 | dip->d1_size = conv4(norm,rip->i_size);
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| 141 | dip->d1_mtime = conv4(norm,rip->i_mtime);
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| 142 | dip->d1_nlinks = (nlink_t) rip->i_nlinks; /* 1 char */
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| 143 | dip->d1_gid = (gid_t) rip->i_gid; /* 1 char */
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| 144 | for (i = 0; i < V1_NR_TZONES; i++)
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| 145 | dip->d1_zone[i] = conv2(norm, (int) rip->i_zone[i]);
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| 146 | }
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| 147 | }
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| 148 |
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| 149 |
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| 150 | /*===========================================================================*
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| 151 | * new_icopy *
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| 152 | *===========================================================================*/
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| 153 | PUBLIC void new_icopy(rip, dip, direction, norm)
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| 154 | register struct inode *rip; /* pointer to the in-core inode struct */
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| 155 | register d2_inode *dip; /* pointer to the d2_inode struct */
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| 156 | int direction; /* READING (from disk) or WRITING (to disk) */
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| 157 | int norm; /* TRUE = do not swap bytes; FALSE = swap */
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| 158 |
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| 159 | {
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| 160 | /* Same as old_icopy, but to/from V2 disk layout. */
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| 161 |
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| 162 | int i;
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| 163 |
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| 164 | if (direction == READING) {
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| 165 | /* Copy V2.x inode to the in-core table, swapping bytes if need be. */
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| 166 | rip->i_mode = conv2(norm,dip->d2_mode);
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| 167 | rip->i_uid = conv2(norm,dip->d2_uid );
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| 168 | rip->i_nlinks = conv2(norm,(int) dip->d2_nlinks);
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| 169 | rip->i_gid = conv2(norm,(int) dip->d2_gid );
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| 170 | rip->i_size = conv4(norm,dip->d2_size);
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| 171 | rip->i_atime = conv4(norm,dip->d2_atime);
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| 172 | rip->i_ctime = conv4(norm,dip->d2_ctime);
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| 173 | rip->i_mtime = conv4(norm,dip->d2_mtime);
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| 174 | rip->i_ndzones = V2_NR_DZONES;
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| 175 | rip->i_nindirs = V2_INDIRECTS(rip->i_sp->s_block_size);
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| 176 | for (i = 0; i < V2_NR_TZONES; i++)
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| 177 | rip->i_zone[i] = conv4(norm, (long) dip->d2_zone[i]);
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| 178 | } else {
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| 179 | /* Copying V2.x inode to disk from the in-core table. */
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| 180 | dip->d2_mode = conv2(norm,rip->i_mode);
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| 181 | dip->d2_uid = conv2(norm,rip->i_uid );
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| 182 | dip->d2_nlinks = conv2(norm,rip->i_nlinks);
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| 183 | dip->d2_gid = conv2(norm,rip->i_gid );
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| 184 | dip->d2_size = conv4(norm,rip->i_size);
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| 185 | dip->d2_atime = conv4(norm,rip->i_atime);
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| 186 | dip->d2_ctime = conv4(norm,rip->i_ctime);
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| 187 | dip->d2_mtime = conv4(norm,rip->i_mtime);
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| 188 | for (i = 0; i < V2_NR_TZONES; i++)
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| 189 | dip->d2_zone[i] = conv4(norm, (long) rip->i_zone[i]);
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| 190 | }
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| 191 | }
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