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2404 | konopa | 1 | /* |
2 | * Copyright (c) 1987,1997, Prentice Hall |
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3 | * All rights reserved. |
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4 | * |
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5 | * Redistribution and use of the MINIX operating system in source and |
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6 | * binary forms, with or without modification, are permitted provided |
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7 | * that the following conditions are met: |
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8 | |||
9 | * - Redistributions of source code must retain the above copyright |
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10 | * notice, this list of conditions and the following disclaimer. |
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11 | |||
12 | * - Redistributions in binary form must reproduce the above |
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13 | * copyright notice, this list of conditions and the following |
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14 | * disclaimer in the documentation and/or other materials provided |
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15 | * with the distribution. |
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16 | |||
17 | * - Neither the name of Prentice Hall nor the names of the software |
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18 | * authors or contributors may be used to endorse or promote |
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19 | * products derived from this software without specific prior |
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20 | * written permission. |
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21 | |||
22 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS, AUTHORS, AND |
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23 | * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, |
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24 | * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
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25 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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26 | * IN NO EVENT SHALL PRENTICE HALL OR ANY AUTHORS OR CONTRIBUTORS BE |
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27 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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28 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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29 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR |
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30 | * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
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31 | * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE |
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32 | * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, |
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33 | * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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34 | */ |
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2435 | jelen | 35 | |
36 | /** @addtogroup FileSystemImpl |
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37 | * @{ |
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38 | */ |
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2404 | konopa | 39 | |
2435 | jelen | 40 | /** |
41 | * @file inode.c |
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42 | * @brief This file manages the inode table. There are procedures to allocate and |
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43 | * deallocate inodes, acquire, erase, and release them, and read and write |
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44 | * them from the disk. |
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2372 | konopa | 45 | */ |
46 | |||
47 | #include "fs.h" |
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48 | #include "block.h" |
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49 | #include "file.h" |
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50 | #include "fproc.h" |
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51 | #include "inode.h" |
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52 | #include "super.h" |
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53 | |||
2435 | jelen | 54 | inode_t inode[NR_INODES]; /**< A variable to store inode entries */ |
2372 | konopa | 55 | |
56 | static void v1_copy_inode(inode_t *rip, d1_inode_t *dip, int normal); |
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57 | static void v2_copy_inode(inode_t *rip, d2_inode_t *dip, int normal); |
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58 | |||
2435 | jelen | 59 | /** |
60 | * Search inode table for a given inode; if not there, read it |
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61 | */ |
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2372 | konopa | 62 | inode_t *get_inode(int numb) |
63 | { |
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64 | /* Find a slot in the inode table, load the specified inode into it, and |
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65 | * return a pointer to the slot. |
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66 | */ |
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67 | |||
68 | register inode_t *rip, *xp; |
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69 | |||
70 | /* Search the inode table both for numb and a free slot. */ |
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71 | xp = NIL_INODE; |
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72 | for (rip = &inode[0]; rip < &inode[NR_INODES]; rip++) { |
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73 | if (rip->i_count > 0) { /* only check used slots for numb */ |
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74 | if (rip->i_num == numb) { |
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75 | /* This is the inode that we are looking for. */ |
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76 | rip->i_count++; |
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77 | return rip; /* numb found */ |
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78 | } |
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79 | } |
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80 | else { |
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81 | xp = rip; /* remember this free slot for later */ |
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82 | } |
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83 | |||
84 | } |
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85 | |||
86 | /* Inode we want is not currently in use. Did we find a free slot? */ |
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87 | if (xp == NIL_INODE) { /* inode table completely full */ |
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88 | err_code = FS_ENFILE; |
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89 | return NIL_INODE; |
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90 | } |
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91 | |||
92 | /* A free inode slot has been located. Load the inode into it. */ |
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93 | xp->i_num = numb; |
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94 | xp->i_count = 1; |
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95 | read_inode(xp); |
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96 | |||
97 | return xp; |
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98 | } |
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99 | |||
2435 | jelen | 100 | /** |
101 | * Read a disk block and extract an inode |
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102 | */ |
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2372 | konopa | 103 | void read_inode(register inode_t *rip) |
104 | { |
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105 | |||
106 | /* An entry in the inode table is to be copied from the disk. */ |
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107 | |||
108 | register block_t *bp; |
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109 | register super_block_t *sp; |
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110 | d1_inode_t *dip1; |
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111 | d2_inode_t *dip2; |
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112 | block_num_t b, offset; |
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113 | |||
114 | /* Get the block where the inode resides. */ |
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115 | sp = get_super(); /* get pointer to super block */ |
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116 | rip->i_sp = sp; /* inode must contain super block pointer */ |
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117 | offset = sp->s_imap_blocks + sp->s_zmap_blocks + 2; |
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118 | b = (block_num_t)(rip->i_num - 1)/sp->s_inodes_per_block + offset; |
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119 | bp = get_block(b); |
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120 | dip1 = bp->b.b__v1_ino + (rip->i_num - 1) % V1_INODES_PER_BLOCK; |
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121 | dip2 = bp->b.b__v2_ino + (rip->i_num - 1) % V2_INODES_PER_BLOCK; |
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122 | |||
123 | /* Copy inode to the in-core table, swapping bytes if need be. */ |
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124 | if (sp->s_version == V1) { |
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125 | v1_copy_inode(rip, dip1, sp->s_native); |
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126 | } |
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127 | else { |
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128 | v2_copy_inode(rip, dip2, sp->s_native); |
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129 | } |
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130 | } |
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2435 | jelen | 131 | |
132 | /** |
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133 | * Copy from disk inode (V1.x) to in-memory inode struct |
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134 | */ |
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2372 | konopa | 135 | void v1_copy_inode(inode_t *rip, d1_inode_t *dip, int normal) |
136 | { |
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137 | /* The V1.x IBM disk, the V1.x 68000 disk, and the V2 disk (same for IBM and |
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138 | * 68000) all have different inode layouts. When an inode is read or written |
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139 | * this routine handles the conversions so that the information in the inode |
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140 | * table is independent of the disk structure from which the inode came. |
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141 | * This routine copies from V1 disks. |
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142 | */ |
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143 | |||
144 | int i; |
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145 | |||
146 | /* Some check is made for valid number of inode. */ |
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147 | if (rip == NIL_INODE || dip == NULL) |
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148 | return; |
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149 | |||
150 | /* Copy V1.x inode to the in-memory table, swapping bytes if need be. */ |
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151 | rip->i_mode = conv2(normal, dip->d1_mode); |
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152 | rip->i_size = conv4(normal, dip->d1_size); |
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153 | rip->i_nlinks = (nlink_t)dip->d1_nlinks; /* 1 char */ |
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154 | rip->i_ndzones = V1_NR_DZONES; |
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155 | rip->i_nindirs = V1_INDIRECTS; |
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156 | |||
157 | for (i = 0; i < V1_NR_TZONES; i++) |
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158 | rip->i_zone[i] = conv2(normal, dip->d1_zone[i]); |
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159 | } |
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2435 | jelen | 160 | |
161 | /** |
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162 | * Copy from disk inode (V2.x) to in-memory inode structs |
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163 | */ |
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2372 | konopa | 164 | void v2_copy_inode(inode_t *rip, d2_inode_t *dip, int normal) |
165 | { |
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166 | /* Same as old_icopy, but to/from V2 disk layout. */ |
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167 | |||
168 | int i; |
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169 | |||
170 | /* Some check is made for valid number of inode. */ |
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171 | if (rip == NIL_INODE || dip == NULL) |
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172 | return; |
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173 | |||
174 | /* Copy V2.x inode to the in-core table, swapping bytes if need be. */ |
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175 | rip->i_mode = conv2(normal, dip->d2_mode); |
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176 | rip->i_size = conv4(normal, dip->d2_size); |
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177 | rip->i_nlinks = conv2(normal, dip->d2_nlinks); |
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178 | rip->i_ndzones = V2_NR_DZONES; |
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179 | rip->i_nindirs = V2_INDIRECTS; |
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180 | |||
181 | for (i = 0; i < V2_NR_TZONES; i++) |
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182 | rip->i_zone[i] = conv4(normal, dip->d2_zone[i]); |
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183 | } |
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184 | |||
2435 | jelen | 185 | /** |
186 | * Indicate that an inode is no longer needed in memory |
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187 | */ |
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2372 | konopa | 188 | void put_inode(inode_t *rip) |
189 | { |
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190 | |||
191 | /* The caller is no longer using this inode. */ |
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192 | |||
193 | if (rip == NIL_INODE) |
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194 | return; |
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195 | |||
196 | rip->i_count--; |
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197 | } |
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2435 | jelen | 198 | |
199 | /** |
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200 | * Indicate that someone else is using an inode table entry |
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201 | */ |
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2372 | konopa | 202 | void dup_inode(inode_t *rip) |
203 | { |
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204 | |||
205 | /* This routine is a simplified form of get_inode() for the case where |
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206 | * the inode pointer is already known. |
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207 | */ |
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208 | |||
209 | if (rip == NIL_INODE) |
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210 | return; |
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211 | |||
212 | rip->i_count++; |
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213 | } |
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214 | |||
2435 | jelen | 215 | |
216 | /** |
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217 | * } |
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218 | */ |
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219 |