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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 | /* * linux/fs/ext/freelists.c * * Copyright (C) 1992 Remy Card (card@masi.ibp.fr) * */ /* freelists.c contains the code that handles the inode and block free lists */ /* The free blocks are managed by a linked list. The super block contains the number of the first free block. This block contains 254 numbers of other free blocks and the number of the next block in the list. When an ext fs is mounted, the number of the first free block is stored in s->u.ext_sb.s_firstfreeblocknumber and the block header is stored in s->u.ext_sb.s_firstfreeblock. u.ext_sb.s_freeblockscount contains the count of free blocks. The free inodes are also managed by a linked list in a similar way. The super block contains the number of the first free inode. This inode contains 14 numbers of other free inodes and the number of the next inode in the list. The number of the first free inode is stored in s->u.ext_sb.s_firstfreeinodenumber and the header of the block containing the inode is stored in s->u.ext_sb.s_firstfreeinodeblock. u.ext_sb.s_freeinodescount contains the count of free inodes. */ #include <linux/sched.h> #include <linux/ext_fs.h> #include <linux/stat.h> #include <linux/kernel.h> #include <linux/string.h> #include <linux/locks.h> void ext_free_block(struct super_block * sb, int block) { struct buffer_head * bh; struct ext_free_block * efb; if (!sb) { printk("trying to free block on non-existent device\n"); return; } lock_super (sb); if (block < sb->u.ext_sb.s_firstdatazone || block >= sb->u.ext_sb.s_nzones) { printk("trying to free block not in datazone\n"); return; } bh = get_hash_table(sb->s_dev, block, sb->s_blocksize); if (bh) bh->b_dirt=0; brelse(bh); if (sb->u.ext_sb.s_firstfreeblock) efb = (struct ext_free_block *) sb->u.ext_sb.s_firstfreeblock->b_data; if (!sb->u.ext_sb.s_firstfreeblock || efb->count == 254) { #ifdef EXTFS_DEBUG printk("ext_free_block: block full, skipping to %d\n", block); #endif if (sb->u.ext_sb.s_firstfreeblock) brelse (sb->u.ext_sb.s_firstfreeblock); if (!(sb->u.ext_sb.s_firstfreeblock = bread (sb->s_dev, block, sb->s_blocksize))) panic ("ext_free_block: unable to read block to free\n"); efb = (struct ext_free_block *) sb->u.ext_sb.s_firstfreeblock->b_data; efb->next = sb->u.ext_sb.s_firstfreeblocknumber; efb->count = 0; sb->u.ext_sb.s_firstfreeblocknumber = block; } else { efb->free[efb->count++] = block; } sb->u.ext_sb.s_freeblockscount ++; sb->s_dirt = 1; mark_buffer_dirty(sb->u.ext_sb.s_firstfreeblock, 1); unlock_super (sb); return; } int ext_new_block(struct super_block * sb) { struct buffer_head * bh; struct ext_free_block * efb; int j; if (!sb) { printk("trying to get new block from non-existent device\n"); return 0; } if (!sb->u.ext_sb.s_firstfreeblock) return 0; lock_super (sb); efb = (struct ext_free_block *) sb->u.ext_sb.s_firstfreeblock->b_data; if (efb->count) { j = efb->free[--efb->count]; mark_buffer_dirty(sb->u.ext_sb.s_firstfreeblock, 1); } else { #ifdef EXTFS_DEBUG printk("ext_new_block: block empty, skipping to %d\n", efb->next); #endif j = sb->u.ext_sb.s_firstfreeblocknumber; sb->u.ext_sb.s_firstfreeblocknumber = efb->next; brelse (sb->u.ext_sb.s_firstfreeblock); if (!sb->u.ext_sb.s_firstfreeblocknumber) { sb->u.ext_sb.s_firstfreeblock = NULL; } else { if (!(sb->u.ext_sb.s_firstfreeblock = bread (sb->s_dev, sb->u.ext_sb.s_firstfreeblocknumber, sb->s_blocksize))) panic ("ext_new_block: unable to read next free block\n"); } } if (j < sb->u.ext_sb.s_firstdatazone || j > sb->u.ext_sb.s_nzones) { printk ("ext_new_block: blk = %d\n", j); printk("allocating block not in data zone\n"); return 0; } sb->u.ext_sb.s_freeblockscount --; sb->s_dirt = 1; if (!(bh=getblk(sb->s_dev, j, sb->s_blocksize))) { printk("new_block: cannot get block"); return 0; } memset(bh->b_data, 0, BLOCK_SIZE); bh->b_uptodate = 1; mark_buffer_dirty(bh, 1); brelse(bh); #ifdef EXTFS_DEBUG printk("ext_new_block: allocating block %d\n", j); #endif unlock_super (sb); return j; } unsigned long ext_count_free_blocks(struct super_block *sb) { #ifdef EXTFS_DEBUG struct buffer_head * bh; struct ext_free_block * efb; unsigned long count, block; lock_super (sb); if (!sb->u.ext_sb.s_firstfreeblock) count = 0; else { efb = (struct ext_free_block *) sb->u.ext_sb.s_firstfreeblock->b_data; count = efb->count + 1; block = efb->next; while (block) { if (!(bh = bread (sb->s_dev, block, sb->s_blocksize))) { printk ("ext_count_free: error while reading free blocks list\n"); block = 0; } else { efb = (struct ext_free_block *) bh->b_data; count += efb->count + 1; block = efb->next; brelse (bh); } } } printk("ext_count_free_blocks: stored = %d, computed = %d\n", sb->u.ext_sb.s_freeblockscount, count); unlock_super (sb); return count; #else return sb->u.ext_sb.s_freeblockscount; #endif } void ext_free_inode(struct inode * inode) { struct buffer_head * bh; struct ext_free_inode * efi; struct super_block * sb; unsigned long block; unsigned long ino; dev_t dev; if (!inode) return; if (!inode->i_dev) { printk("free_inode: inode has no device\n"); return; } if (inode->i_count != 1) { printk("free_inode: inode has count=%d\n",inode->i_count); return; } if (inode->i_nlink) { printk("free_inode: inode has nlink=%d\n",inode->i_nlink); return; } if (!inode->i_sb) { printk("free_inode: inode on non-existent device\n"); return; } sb = inode->i_sb; ino = inode->i_ino; dev = inode->i_dev; clear_inode(inode); lock_super (sb); if (ino < 1 || ino > sb->u.ext_sb.s_ninodes) { printk("free_inode: inode 0 or non-existent inode\n"); unlock_super (sb); return; } if (sb->u.ext_sb.s_firstfreeinodeblock) efi = ((struct ext_free_inode *) sb->u.ext_sb.s_firstfreeinodeblock->b_data) + (sb->u.ext_sb.s_firstfreeinodenumber-1)%EXT_INODES_PER_BLOCK; if (!sb->u.ext_sb.s_firstfreeinodeblock || efi->count == 14) { #ifdef EXTFS_DEBUG printk("ext_free_inode: inode full, skipping to %d\n", ino); #endif if (sb->u.ext_sb.s_firstfreeinodeblock) brelse (sb->u.ext_sb.s_firstfreeinodeblock); block = 2 + (ino - 1) / EXT_INODES_PER_BLOCK; if (!(bh = bread(dev, block, sb->s_blocksize))) panic("ext_free_inode: unable to read inode block\n"); efi = ((struct ext_free_inode *) bh->b_data) + (ino - 1) % EXT_INODES_PER_BLOCK; efi->next = sb->u.ext_sb.s_firstfreeinodenumber; efi->count = 0; sb->u.ext_sb.s_firstfreeinodenumber = ino; sb->u.ext_sb.s_firstfreeinodeblock = bh; } else { efi->free[efi->count++] = ino; } sb->u.ext_sb.s_freeinodescount ++; sb->s_dirt = 1; mark_buffer_dirty(sb->u.ext_sb.s_firstfreeinodeblock, 1); unlock_super (sb); } struct inode * ext_new_inode(const struct inode * dir) { struct super_block * sb; struct inode * inode; struct ext_free_inode * efi; unsigned long block; int j; if (!dir || !(inode=get_empty_inode())) return NULL; sb = dir->i_sb; inode->i_sb = sb; inode->i_flags = sb->s_flags; if (!sb->u.ext_sb.s_firstfreeinodeblock) return 0; lock_super (sb); efi = ((struct ext_free_inode *) sb->u.ext_sb.s_firstfreeinodeblock->b_data) + (sb->u.ext_sb.s_firstfreeinodenumber-1)%EXT_INODES_PER_BLOCK; if (efi->count) { j = efi->free[--efi->count]; mark_buffer_dirty(sb->u.ext_sb.s_firstfreeinodeblock, 1); } else { #ifdef EXTFS_DEBUG printk("ext_free_inode: inode empty, skipping to %d\n", efi->next); #endif j = sb->u.ext_sb.s_firstfreeinodenumber; if (efi->next > sb->u.ext_sb.s_ninodes) { printk ("efi->next = %ld\n", efi->next); panic ("ext_new_inode: bad inode number in free list\n"); } sb->u.ext_sb.s_firstfreeinodenumber = efi->next; block = 2 + (((unsigned long) efi->next) - 1) / EXT_INODES_PER_BLOCK; brelse (sb->u.ext_sb.s_firstfreeinodeblock); if (!sb->u.ext_sb.s_firstfreeinodenumber) { sb->u.ext_sb.s_firstfreeinodeblock = NULL; } else { if (!(sb->u.ext_sb.s_firstfreeinodeblock = bread(sb->s_dev, block, sb->s_blocksize))) panic ("ext_new_inode: unable to read next free inode block\n"); } } sb->u.ext_sb.s_freeinodescount --; sb->s_dirt = 1; inode->i_count = 1; inode->i_nlink = 1; inode->i_dev = sb->s_dev; inode->i_uid = current->fsuid; inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid; inode->i_dirt = 1; inode->i_ino = j; inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; inode->i_op = NULL; inode->i_blocks = inode->i_blksize = 0; insert_inode_hash(inode); #ifdef EXTFS_DEBUG printk("ext_new_inode : allocating inode %d\n", inode->i_ino); #endif unlock_super (sb); return inode; } unsigned long ext_count_free_inodes(struct super_block *sb) { #ifdef EXTFS_DEBUG struct buffer_head * bh; struct ext_free_inode * efi; unsigned long count, block, ino; lock_super (sb); if (!sb->u.ext_sb.s_firstfreeinodeblock) count = 0; else { efi = ((struct ext_free_inode *) sb->u.ext_sb.s_firstfreeinodeblock->b_data) + ((sb->u.ext_sb.s_firstfreeinodenumber-1)%EXT_INODES_PER_BLOCK); count = efi->count + 1; ino = efi->next; while (ino) { if (ino < 1 || ino > sb->u.ext_sb.s_ninodes) { printk ("u.ext_sb.s_firstfreeinodenumber = %d, ino = %d\n", (int) sb->u.ext_sb.s_firstfreeinodenumber,ino); panic ("ext_count_fre_inodes: bad inode number in free list\n"); } block = 2 + ((ino - 1) / EXT_INODES_PER_BLOCK); if (!(bh = bread (sb->s_dev, block, sb->s_blocksize))) { printk ("ext_count_free_inodes: error while reading free inodes list\n"); block = 0; } else { efi = ((struct ext_free_inode *) bh->b_data) + ((ino - 1) % EXT_INODES_PER_BLOCK); count += efi->count + 1; ino = efi->next; brelse (bh); } } } printk("ext_count_free_inodes: stored = %d, computed = %d\n", sb->u.ext_sb.s_freeinodescount, count); unlock_super (sb); return count; #else return sb->u.ext_sb.s_freeinodescount; #endif } |