Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/fs/bfs/dir.c
Version:
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1 /* 2 * fs/bfs/dir.c 3 * BFS directory operations. 4 * Copyright (C) 1999,2000 Tigran Aivazian <tigran@veritas.com> 5 */ 6 7 #include <linux/sched.h> 8 #include <linux/string.h> 9 #include <linux/bfs_fs.h> 10 #include <linux/locks.h> 11 12 #include "bfs_defs.h" 13 14 #undef DEBUG 15 16 #ifdef DEBUG 17 #define dprintf(x...) printf(x) 18 #else 19 #define dprintf(x...) 20 #endif 21 22 static int bfs_add_entry(struct inode * dir, const char * name, int namelen, int ino); 23 static struct buffer_head * bfs_find_entry(struct inode * dir, 24 const char * name, int namelen, struct bfs_dirent ** res_dir); 25 26 static int bfs_readdir(struct file * f, void * dirent, filldir_t filldir) 27 { 28 struct inode * dir = f->f_dentry->d_inode; 29 struct buffer_head * bh; 30 struct bfs_dirent * de; 31 kdev_t dev = dir->i_dev; 32 unsigned int offset; 33 int block; 34 35 if (f->f_pos & (BFS_DIRENT_SIZE-1)) { 36 printf("Bad f_pos=%08lx for %s:%08lx\n", (unsigned long)f->f_pos, 37 bdevname(dev), dir->i_ino); 38 return -EBADF; 39 } 40 41 while (f->f_pos < dir->i_size) { 42 offset = f->f_pos & (BFS_BSIZE-1); 43 block = dir->iu_sblock + (f->f_pos >> BFS_BSIZE_BITS); 44 bh = sb_bread(dir->i_sb, block); 45 if (!bh) { 46 f->f_pos += BFS_BSIZE - offset; 47 continue; 48 } 49 do { 50 de = (struct bfs_dirent *)(bh->b_data + offset); 51 if (de->ino) { 52 int size = strnlen(de->name, BFS_NAMELEN); 53 if (filldir(dirent, de->name, size, f->f_pos, de->ino, DT_UNKNOWN) < 0) { 54 brelse(bh); 55 return 0; 56 } 57 } 58 offset += BFS_DIRENT_SIZE; 59 f->f_pos += BFS_DIRENT_SIZE; 60 } while (offset < BFS_BSIZE && f->f_pos < dir->i_size); 61 brelse(bh); 62 } 63 64 UPDATE_ATIME(dir); 65 return 0; 66 } 67 68 struct file_operations bfs_dir_operations = { 69 read: generic_read_dir, 70 readdir: bfs_readdir, 71 fsync: file_fsync, 72 }; 73 74 extern void dump_imap(const char *, struct super_block *); 75 76 static int bfs_create(struct inode * dir, struct dentry * dentry, int mode) 77 { 78 int err; 79 struct inode * inode; 80 struct super_block * s = dir->i_sb; 81 unsigned long ino; 82 83 inode = new_inode(s); 84 if (!inode) 85 return -ENOSPC; 86 ino = find_first_zero_bit(s->su_imap, s->su_lasti); 87 if (ino > s->su_lasti) { 88 iput(inode); 89 return -ENOSPC; 90 } 91 set_bit(ino, s->su_imap); 92 s->su_freei--; 93 inode->i_uid = current->fsuid; 94 inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid; 95 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 96 inode->i_blocks = inode->i_blksize = 0; 97 inode->i_op = &bfs_file_inops; 98 inode->i_fop = &bfs_file_operations; 99 inode->i_mapping->a_ops = &bfs_aops; 100 inode->i_mode = mode; 101 inode->i_ino = inode->iu_dsk_ino = ino; 102 inode->iu_sblock = inode->iu_eblock = 0; 103 insert_inode_hash(inode); 104 mark_inode_dirty(inode); 105 dump_imap("create",s); 106 107 err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len, inode->i_ino); 108 if (err) { 109 inode->i_nlink--; 110 mark_inode_dirty(inode); 111 iput(inode); 112 return err; 113 } 114 d_instantiate(dentry, inode); 115 return 0; 116 } 117 118 static struct dentry * bfs_lookup(struct inode * dir, struct dentry * dentry) 119 { 120 struct inode * inode = NULL; 121 struct buffer_head * bh; 122 struct bfs_dirent * de; 123 124 if (dentry->d_name.len > BFS_NAMELEN) 125 return ERR_PTR(-ENAMETOOLONG); 126 127 bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de); 128 if (bh) { 129 unsigned long ino = le32_to_cpu(de->ino); 130 brelse(bh); 131 inode = iget(dir->i_sb, ino); 132 if (!inode) 133 return ERR_PTR(-EACCES); 134 } 135 d_add(dentry, inode); 136 return NULL; 137 } 138 139 static int bfs_link(struct dentry * old, struct inode * dir, struct dentry * new) 140 { 141 struct inode * inode = old->d_inode; 142 int err; 143 144 if (S_ISDIR(inode->i_mode)) 145 return -EPERM; 146 147 err = bfs_add_entry(dir, new->d_name.name, new->d_name.len, inode->i_ino); 148 if (err) 149 return err; 150 inode->i_nlink++; 151 inode->i_ctime = CURRENT_TIME; 152 mark_inode_dirty(inode); 153 atomic_inc(&inode->i_count); 154 d_instantiate(new, inode); 155 return 0; 156 } 157 158 159 static int bfs_unlink(struct inode * dir, struct dentry * dentry) 160 { 161 int error = -ENOENT; 162 struct inode * inode; 163 struct buffer_head * bh; 164 struct bfs_dirent * de; 165 166 inode = dentry->d_inode; 167 bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de); 168 if (!bh || de->ino != inode->i_ino) 169 goto out_brelse; 170 171 if (!inode->i_nlink) { 172 printf("unlinking non-existent file %s:%lu (nlink=%d)\n", bdevname(inode->i_dev), 173 inode->i_ino, inode->i_nlink); 174 inode->i_nlink = 1; 175 } 176 de->ino = 0; 177 dir->i_version = ++event; 178 mark_buffer_dirty(bh); 179 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 180 mark_inode_dirty(dir); 181 inode->i_nlink--; 182 inode->i_ctime = dir->i_ctime; 183 mark_inode_dirty(inode); 184 error = 0; 185 186 out_brelse: 187 brelse(bh); 188 return error; 189 } 190 191 static int bfs_rename(struct inode * old_dir, struct dentry * old_dentry, 192 struct inode * new_dir, struct dentry * new_dentry) 193 { 194 struct inode * old_inode, * new_inode; 195 struct buffer_head * old_bh, * new_bh; 196 struct bfs_dirent * old_de, * new_de; 197 int error = -ENOENT; 198 199 old_bh = new_bh = NULL; 200 old_inode = old_dentry->d_inode; 201 if (S_ISDIR(old_inode->i_mode)) 202 return -EINVAL; 203 204 old_bh = bfs_find_entry(old_dir, 205 old_dentry->d_name.name, 206 old_dentry->d_name.len, &old_de); 207 208 if (!old_bh || old_de->ino != old_inode->i_ino) 209 goto end_rename; 210 211 error = -EPERM; 212 new_inode = new_dentry->d_inode; 213 new_bh = bfs_find_entry(new_dir, 214 new_dentry->d_name.name, 215 new_dentry->d_name.len, &new_de); 216 217 if (new_bh && !new_inode) { 218 brelse(new_bh); 219 new_bh = NULL; 220 } 221 if (!new_bh) { 222 error = bfs_add_entry(new_dir, 223 new_dentry->d_name.name, 224 new_dentry->d_name.len, old_inode->i_ino); 225 if (error) 226 goto end_rename; 227 } 228 old_de->ino = 0; 229 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME; 230 old_dir->i_version = ++event; 231 mark_inode_dirty(old_dir); 232 if (new_inode) { 233 new_inode->i_nlink--; 234 new_inode->i_ctime = CURRENT_TIME; 235 mark_inode_dirty(new_inode); 236 } 237 mark_buffer_dirty(old_bh); 238 error = 0; 239 240 end_rename: 241 brelse(old_bh); 242 brelse(new_bh); 243 return error; 244 } 245 246 struct inode_operations bfs_dir_inops = { 247 create: bfs_create, 248 lookup: bfs_lookup, 249 link: bfs_link, 250 unlink: bfs_unlink, 251 rename: bfs_rename, 252 }; 253 254 static int bfs_add_entry(struct inode * dir, const char * name, int namelen, int ino) 255 { 256 struct buffer_head * bh; 257 struct bfs_dirent * de; 258 int block, sblock, eblock, off; 259 int i; 260 261 dprintf("name=%s, namelen=%d\n", name, namelen); 262 263 if (!namelen) 264 return -ENOENT; 265 if (namelen > BFS_NAMELEN) 266 return -ENAMETOOLONG; 267 268 sblock = dir->iu_sblock; 269 eblock = dir->iu_eblock; 270 for (block=sblock; block<=eblock; block++) { 271 bh = sb_bread(dir->i_sb, block); 272 if(!bh) 273 return -ENOSPC; 274 for (off=0; off<BFS_BSIZE; off+=BFS_DIRENT_SIZE) { 275 de = (struct bfs_dirent *)(bh->b_data + off); 276 if (!de->ino) { 277 if ((block-sblock)*BFS_BSIZE + off >= dir->i_size) { 278 dir->i_size += BFS_DIRENT_SIZE; 279 dir->i_ctime = CURRENT_TIME; 280 } 281 dir->i_mtime = CURRENT_TIME; 282 mark_inode_dirty(dir); 283 dir->i_version = ++event; 284 de->ino = ino; 285 for (i=0; i<BFS_NAMELEN; i++) 286 de->name[i] = (i < namelen) ? name[i] : 0; 287 mark_buffer_dirty(bh); 288 brelse(bh); 289 return 0; 290 } 291 } 292 brelse(bh); 293 } 294 return -ENOSPC; 295 } 296 297 static inline int bfs_namecmp(int len, const char * name, const char * buffer) 298 { 299 if (len < BFS_NAMELEN && buffer[len]) 300 return 0; 301 return !memcmp(name, buffer, len); 302 } 303 304 static struct buffer_head * bfs_find_entry(struct inode * dir, 305 const char * name, int namelen, struct bfs_dirent ** res_dir) 306 { 307 unsigned long block, offset; 308 struct buffer_head * bh; 309 struct bfs_dirent * de; 310 311 *res_dir = NULL; 312 if (namelen > BFS_NAMELEN) 313 return NULL; 314 bh = NULL; 315 block = offset = 0; 316 while (block * BFS_BSIZE + offset < dir->i_size) { 317 if (!bh) { 318 bh = sb_bread(dir->i_sb, dir->iu_sblock + block); 319 if (!bh) { 320 block++; 321 continue; 322 } 323 } 324 de = (struct bfs_dirent *)(bh->b_data + offset); 325 offset += BFS_DIRENT_SIZE; 326 if (de->ino && bfs_namecmp(namelen, name, de->name)) { 327 *res_dir = de; 328 return bh; 329 } 330 if (offset < bh->b_size) 331 continue; 332 brelse(bh); 333 bh = NULL; 334 offset = 0; 335 block++; 336 } 337 brelse(bh); 338 return NULL; 339 }
Cache object: 26f8a30536ce13dc273cc15986c94d9c
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