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_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 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 = inode->i_blksize = 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->i_nlink--; 121 mark_inode_dirty(inode); 122 iput(inode); 123 unlock_kernel(); 124 return err; 125 } 126 unlock_kernel(); 127 d_instantiate(dentry, inode); 128 return 0; 129 } 130 131 static struct dentry * bfs_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd) 132 { 133 struct inode * inode = NULL; 134 struct buffer_head * bh; 135 struct bfs_dirent * de; 136 137 if (dentry->d_name.len > BFS_NAMELEN) 138 return ERR_PTR(-ENAMETOOLONG); 139 140 lock_kernel(); 141 bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de); 142 if (bh) { 143 unsigned long ino = (unsigned long)le16_to_cpu(de->ino); 144 brelse(bh); 145 inode = iget(dir->i_sb, ino); 146 if (!inode) { 147 unlock_kernel(); 148 return ERR_PTR(-EACCES); 149 } 150 } 151 unlock_kernel(); 152 d_add(dentry, inode); 153 return NULL; 154 } 155 156 static int bfs_link(struct dentry * old, struct inode * dir, struct dentry * new) 157 { 158 struct inode * inode = old->d_inode; 159 int err; 160 161 lock_kernel(); 162 err = bfs_add_entry(dir, new->d_name.name, new->d_name.len, inode->i_ino); 163 if (err) { 164 unlock_kernel(); 165 return err; 166 } 167 inode->i_nlink++; 168 inode->i_ctime = CURRENT_TIME_SEC; 169 mark_inode_dirty(inode); 170 atomic_inc(&inode->i_count); 171 d_instantiate(new, inode); 172 unlock_kernel(); 173 return 0; 174 } 175 176 177 static int bfs_unlink(struct inode * dir, struct dentry * dentry) 178 { 179 int error = -ENOENT; 180 struct inode * inode; 181 struct buffer_head * bh; 182 struct bfs_dirent * de; 183 184 inode = dentry->d_inode; 185 lock_kernel(); 186 bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de); 187 if (!bh || le16_to_cpu(de->ino) != inode->i_ino) 188 goto out_brelse; 189 190 if (!inode->i_nlink) { 191 printf("unlinking non-existent file %s:%lu (nlink=%d)\n", inode->i_sb->s_id, 192 inode->i_ino, inode->i_nlink); 193 inode->i_nlink = 1; 194 } 195 de->ino = 0; 196 mark_buffer_dirty(bh); 197 dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC; 198 mark_inode_dirty(dir); 199 inode->i_nlink--; 200 inode->i_ctime = dir->i_ctime; 201 mark_inode_dirty(inode); 202 error = 0; 203 204 out_brelse: 205 brelse(bh); 206 unlock_kernel(); 207 return error; 208 } 209 210 static int bfs_rename(struct inode * old_dir, struct dentry * old_dentry, 211 struct inode * new_dir, struct dentry * new_dentry) 212 { 213 struct inode * old_inode, * new_inode; 214 struct buffer_head * old_bh, * new_bh; 215 struct bfs_dirent * old_de, * new_de; 216 int error = -ENOENT; 217 218 old_bh = new_bh = NULL; 219 old_inode = old_dentry->d_inode; 220 if (S_ISDIR(old_inode->i_mode)) 221 return -EINVAL; 222 223 lock_kernel(); 224 old_bh = bfs_find_entry(old_dir, 225 old_dentry->d_name.name, 226 old_dentry->d_name.len, &old_de); 227 228 if (!old_bh || le16_to_cpu(old_de->ino) != old_inode->i_ino) 229 goto end_rename; 230 231 error = -EPERM; 232 new_inode = new_dentry->d_inode; 233 new_bh = bfs_find_entry(new_dir, 234 new_dentry->d_name.name, 235 new_dentry->d_name.len, &new_de); 236 237 if (new_bh && !new_inode) { 238 brelse(new_bh); 239 new_bh = NULL; 240 } 241 if (!new_bh) { 242 error = bfs_add_entry(new_dir, 243 new_dentry->d_name.name, 244 new_dentry->d_name.len, old_inode->i_ino); 245 if (error) 246 goto end_rename; 247 } 248 old_de->ino = 0; 249 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC; 250 mark_inode_dirty(old_dir); 251 if (new_inode) { 252 new_inode->i_nlink--; 253 new_inode->i_ctime = CURRENT_TIME_SEC; 254 mark_inode_dirty(new_inode); 255 } 256 mark_buffer_dirty(old_bh); 257 error = 0; 258 259 end_rename: 260 unlock_kernel(); 261 brelse(old_bh); 262 brelse(new_bh); 263 return error; 264 } 265 266 struct inode_operations bfs_dir_inops = { 267 .create = bfs_create, 268 .lookup = bfs_lookup, 269 .link = bfs_link, 270 .unlink = bfs_unlink, 271 .rename = bfs_rename, 272 }; 273 274 static int bfs_add_entry(struct inode * dir, const unsigned char * name, int namelen, int ino) 275 { 276 struct buffer_head * bh; 277 struct bfs_dirent * de; 278 int block, sblock, eblock, off, eoff; 279 int i; 280 281 dprintf("name=%s, namelen=%d\n", name, namelen); 282 283 if (!namelen) 284 return -ENOENT; 285 if (namelen > BFS_NAMELEN) 286 return -ENAMETOOLONG; 287 288 sblock = BFS_I(dir)->i_sblock; 289 eblock = BFS_I(dir)->i_eblock; 290 eoff = dir->i_size % BFS_BSIZE; 291 for (block=sblock; block<=eblock; block++) { 292 bh = sb_bread(dir->i_sb, block); 293 if(!bh) 294 return -ENOSPC; 295 for (off=0; off<BFS_BSIZE; off+=BFS_DIRENT_SIZE) { 296 de = (struct bfs_dirent *)(bh->b_data + off); 297 if (block==eblock && off>=eoff) { 298 /* Do not read/interpret the garbage in the end of eblock. */ 299 de->ino = 0; 300 } 301 if (!de->ino) { 302 if ((block-sblock)*BFS_BSIZE + off >= dir->i_size) { 303 dir->i_size += BFS_DIRENT_SIZE; 304 dir->i_ctime = CURRENT_TIME_SEC; 305 } 306 dir->i_mtime = CURRENT_TIME_SEC; 307 mark_inode_dirty(dir); 308 de->ino = cpu_to_le16((u16)ino); 309 for (i=0; i<BFS_NAMELEN; i++) 310 de->name[i] = (i < namelen) ? name[i] : 0; 311 mark_buffer_dirty(bh); 312 brelse(bh); 313 return 0; 314 } 315 } 316 brelse(bh); 317 } 318 return -ENOSPC; 319 } 320 321 static inline int bfs_namecmp(int len, const unsigned char * name, const char * buffer) 322 { 323 if (len < BFS_NAMELEN && buffer[len]) 324 return 0; 325 return !memcmp(name, buffer, len); 326 } 327 328 static struct buffer_head * bfs_find_entry(struct inode * dir, 329 const unsigned char * name, int namelen, struct bfs_dirent ** res_dir) 330 { 331 unsigned long block, offset; 332 struct buffer_head * bh; 333 struct bfs_dirent * de; 334 335 *res_dir = NULL; 336 if (namelen > BFS_NAMELEN) 337 return NULL; 338 bh = NULL; 339 block = offset = 0; 340 while (block * BFS_BSIZE + offset < dir->i_size) { 341 if (!bh) { 342 bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block); 343 if (!bh) { 344 block++; 345 continue; 346 } 347 } 348 de = (struct bfs_dirent *)(bh->b_data + offset); 349 offset += BFS_DIRENT_SIZE; 350 if (le16_to_cpu(de->ino) && bfs_namecmp(namelen, name, de->name)) { 351 *res_dir = de; 352 return bh; 353 } 354 if (offset < bh->b_size) 355 continue; 356 brelse(bh); 357 bh = NULL; 358 offset = 0; 359 block++; 360 } 361 brelse(bh); 362 return NULL; 363 } 364