1 /* 2 * fs/bfs/dir.c 3 * BFS directory operations. 4 * Copyright (C) 1999,2000 Tigran Aivazian <tigran@veritas.com> 5 * Made endianness-clean by Andrew Stribblehill <ads@wompom.org> 2005 6 */ 7 8 #include <linux/time.h> 9 #include <linux/string.h> 10 #include <linux/fs.h> 11 #include <linux/smp_lock.h> 12 #include <linux/buffer_head.h> 13 #include <linux/sched.h> 14 #include "bfs.h" 15 16 #undef DEBUG 17 18 #ifdef DEBUG 19 #define dprintf(x...) printf(x) 20 #else 21 #define dprintf(x...) 22 #endif 23 24 static int bfs_add_entry(struct inode * dir, const unsigned char * name, int namelen, int ino); 25 static struct buffer_head * bfs_find_entry(struct inode * dir, 26 const unsigned char * name, int namelen, struct bfs_dirent ** res_dir); 27 28 static int bfs_readdir(struct file * f, void * dirent, filldir_t filldir) 29 { 30 struct inode * dir = f->f_path.dentry->d_inode; 31 struct buffer_head * bh; 32 struct bfs_dirent * de; 33 unsigned int offset; 34 int block; 35 36 lock_kernel(); 37 38 if (f->f_pos & (BFS_DIRENT_SIZE-1)) { 39 printf("Bad f_pos=%08lx for %s:%08lx\n", (unsigned long)f->f_pos, 40 dir->i_sb->s_id, dir->i_ino); 41 unlock_kernel(); 42 return -EBADF; 43 } 44 45 while (f->f_pos < dir->i_size) { 46 offset = f->f_pos & (BFS_BSIZE-1); 47 block = BFS_I(dir)->i_sblock + (f->f_pos >> BFS_BSIZE_BITS); 48 bh = sb_bread(dir->i_sb, block); 49 if (!bh) { 50 f->f_pos += BFS_BSIZE - offset; 51 continue; 52 } 53 do { 54 de = (struct bfs_dirent *)(bh->b_data + offset); 55 if (de->ino) { 56 int size = strnlen(de->name, BFS_NAMELEN); 57 if (filldir(dirent, de->name, size, f->f_pos, le16_to_cpu(de->ino), DT_UNKNOWN) < 0) { 58 brelse(bh); 59 unlock_kernel(); 60 return 0; 61 } 62 } 63 offset += BFS_DIRENT_SIZE; 64 f->f_pos += BFS_DIRENT_SIZE; 65 } while (offset < BFS_BSIZE && f->f_pos < dir->i_size); 66 brelse(bh); 67 } 68 69 unlock_kernel(); 70 return 0; 71 } 72 73 const struct file_operations bfs_dir_operations = { 74 .read = generic_read_dir, 75 .readdir = bfs_readdir, 76 .fsync = file_fsync, 77 }; 78 79 extern void dump_imap(const char *, struct super_block *); 80 81 static int bfs_create(struct inode * dir, struct dentry * dentry, int mode, 82 struct nameidata *nd) 83 { 84 int err; 85 struct inode * inode; 86 struct super_block * s = dir->i_sb; 87 struct bfs_sb_info * info = BFS_SB(s); 88 unsigned long ino; 89 90 inode = new_inode(s); 91 if (!inode) 92 return -ENOSPC; 93 lock_kernel(); 94 ino = find_first_zero_bit(info->si_imap, info->si_lasti); 95 if (ino > info->si_lasti) { 96 unlock_kernel(); 97 iput(inode); 98 return -ENOSPC; 99 } 100 set_bit(ino, info->si_imap); 101 info->si_freei--; 102 inode->i_uid = current->fsuid; 103 inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid; 104 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC; 105 inode->i_blocks = 0; 106 inode->i_op = &bfs_file_inops; 107 inode->i_fop = &bfs_file_operations; 108 inode->i_mapping->a_ops = &bfs_aops; 109 inode->i_mode = mode; 110 inode->i_ino = ino; 111 BFS_I(inode)->i_dsk_ino = ino; 112 BFS_I(inode)->i_sblock = 0; 113 BFS_I(inode)->i_eblock = 0; 114 insert_inode_hash(inode); 115 mark_inode_dirty(inode); 116 dump_imap("create",s); 117 118 err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len, inode->i_ino); 119 if (err) { 120 inode_dec_link_count(inode); 121 iput(inode); 122 unlock_kernel(); 123 return err; 124 } 125 unlock_kernel(); 126 d_instantiate(dentry, inode); 127 return 0; 128 } 129 130 static struct dentry * bfs_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd) 131 { 132 struct inode * inode = NULL; 133 struct buffer_head * bh; 134 struct bfs_dirent * de; 135 136 if (dentry->d_name.len > BFS_NAMELEN) 137 return ERR_PTR(-ENAMETOOLONG); 138 139 lock_kernel(); 140 bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de); 141 if (bh) { 142 unsigned long ino = (unsigned long)le16_to_cpu(de->ino); 143 brelse(bh); 144 inode = iget(dir->i_sb, ino); 145 if (!inode) { 146 unlock_kernel(); 147 return ERR_PTR(-EACCES); 148 } 149 } 150 unlock_kernel(); 151 d_add(dentry, inode); 152 return NULL; 153 } 154 155 static int bfs_link(struct dentry * old, struct inode * dir, struct dentry * new) 156 { 157 struct inode * inode = old->d_inode; 158 int err; 159 160 lock_kernel(); 161 err = bfs_add_entry(dir, new->d_name.name, new->d_name.len, inode->i_ino); 162 if (err) { 163 unlock_kernel(); 164 return err; 165 } 166 inc_nlink(inode); 167 inode->i_ctime = CURRENT_TIME_SEC; 168 mark_inode_dirty(inode); 169 atomic_inc(&inode->i_count); 170 d_instantiate(new, inode); 171 unlock_kernel(); 172 return 0; 173 } 174 175 176 static int bfs_unlink(struct inode * dir, struct dentry * dentry) 177 { 178 int error = -ENOENT; 179 struct inode * inode; 180 struct buffer_head * bh; 181 struct bfs_dirent * de; 182 183 inode = dentry->d_inode; 184 lock_kernel(); 185 bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de); 186 if (!bh || le16_to_cpu(de->ino) != inode->i_ino) 187 goto out_brelse; 188 189 if (!inode->i_nlink) { 190 printf("unlinking non-existent file %s:%lu (nlink=%d)\n", inode->i_sb->s_id, 191 inode->i_ino, inode->i_nlink); 192 inode->i_nlink = 1; 193 } 194 de->ino = 0; 195 mark_buffer_dirty(bh); 196 dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC; 197 mark_inode_dirty(dir); 198 inode->i_ctime = dir->i_ctime; 199 inode_dec_link_count(inode); 200 error = 0; 201 202 out_brelse: 203 brelse(bh); 204 unlock_kernel(); 205 return error; 206 } 207 208 static int bfs_rename(struct inode * old_dir, struct dentry * old_dentry, 209 struct inode * new_dir, struct dentry * new_dentry) 210 { 211 struct inode * old_inode, * new_inode; 212 struct buffer_head * old_bh, * new_bh; 213 struct bfs_dirent * old_de, * new_de; 214 int error = -ENOENT; 215 216 old_bh = new_bh = NULL; 217 old_inode = old_dentry->d_inode; 218 if (S_ISDIR(old_inode->i_mode)) 219 return -EINVAL; 220 221 lock_kernel(); 222 old_bh = bfs_find_entry(old_dir, 223 old_dentry->d_name.name, 224 old_dentry->d_name.len, &old_de); 225 226 if (!old_bh || le16_to_cpu(old_de->ino) != old_inode->i_ino) 227 goto end_rename; 228 229 error = -EPERM; 230 new_inode = new_dentry->d_inode; 231 new_bh = bfs_find_entry(new_dir, 232 new_dentry->d_name.name, 233 new_dentry->d_name.len, &new_de); 234 235 if (new_bh && !new_inode) { 236 brelse(new_bh); 237 new_bh = NULL; 238 } 239 if (!new_bh) { 240 error = bfs_add_entry(new_dir, 241 new_dentry->d_name.name, 242 new_dentry->d_name.len, old_inode->i_ino); 243 if (error) 244 goto end_rename; 245 } 246 old_de->ino = 0; 247 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC; 248 mark_inode_dirty(old_dir); 249 if (new_inode) { 250 new_inode->i_ctime = CURRENT_TIME_SEC; 251 inode_dec_link_count(new_inode); 252 } 253 mark_buffer_dirty(old_bh); 254 error = 0; 255 256 end_rename: 257 unlock_kernel(); 258 brelse(old_bh); 259 brelse(new_bh); 260 return error; 261 } 262 263 const struct inode_operations bfs_dir_inops = { 264 .create = bfs_create, 265 .lookup = bfs_lookup, 266 .link = bfs_link, 267 .unlink = bfs_unlink, 268 .rename = bfs_rename, 269 }; 270 271 static int bfs_add_entry(struct inode * dir, const unsigned char * name, int namelen, int ino) 272 { 273 struct buffer_head * bh; 274 struct bfs_dirent * de; 275 int block, sblock, eblock, off, eoff; 276 int i; 277 278 dprintf("name=%s, namelen=%d\n", name, namelen); 279 280 if (!namelen) 281 return -ENOENT; 282 if (namelen > BFS_NAMELEN) 283 return -ENAMETOOLONG; 284 285 sblock = BFS_I(dir)->i_sblock; 286 eblock = BFS_I(dir)->i_eblock; 287 eoff = dir->i_size % BFS_BSIZE; 288 for (block=sblock; block<=eblock; block++) { 289 bh = sb_bread(dir->i_sb, block); 290 if(!bh) 291 return -ENOSPC; 292 for (off=0; off<BFS_BSIZE; off+=BFS_DIRENT_SIZE) { 293 de = (struct bfs_dirent *)(bh->b_data + off); 294 if (block==eblock && off>=eoff) { 295 /* Do not read/interpret the garbage in the end of eblock. */ 296 de->ino = 0; 297 } 298 if (!de->ino) { 299 if ((block-sblock)*BFS_BSIZE + off >= dir->i_size) { 300 dir->i_size += BFS_DIRENT_SIZE; 301 dir->i_ctime = CURRENT_TIME_SEC; 302 } 303 dir->i_mtime = CURRENT_TIME_SEC; 304 mark_inode_dirty(dir); 305 de->ino = cpu_to_le16((u16)ino); 306 for (i=0; i<BFS_NAMELEN; i++) 307 de->name[i] = (i < namelen) ? name[i] : 0; 308 mark_buffer_dirty(bh); 309 brelse(bh); 310 return 0; 311 } 312 } 313 brelse(bh); 314 } 315 return -ENOSPC; 316 } 317 318 static inline int bfs_namecmp(int len, const unsigned char * name, const char * buffer) 319 { 320 if (len < BFS_NAMELEN && buffer[len]) 321 return 0; 322 return !memcmp(name, buffer, len); 323 } 324 325 static struct buffer_head * bfs_find_entry(struct inode * dir, 326 const unsigned char * name, int namelen, struct bfs_dirent ** res_dir) 327 { 328 unsigned long block, offset; 329 struct buffer_head * bh; 330 struct bfs_dirent * de; 331 332 *res_dir = NULL; 333 if (namelen > BFS_NAMELEN) 334 return NULL; 335 bh = NULL; 336 block = offset = 0; 337 while (block * BFS_BSIZE + offset < dir->i_size) { 338 if (!bh) { 339 bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block); 340 if (!bh) { 341 block++; 342 continue; 343 } 344 } 345 de = (struct bfs_dirent *)(bh->b_data + offset); 346 offset += BFS_DIRENT_SIZE; 347 if (le16_to_cpu(de->ino) && bfs_namecmp(namelen, name, de->name)) { 348 *res_dir = de; 349 return bh; 350 } 351 if (offset < bh->b_size) 352 continue; 353 brelse(bh); 354 bh = NULL; 355 offset = 0; 356 block++; 357 } 358 brelse(bh); 359 return NULL; 360 } 361