1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * fs/bfs/dir.c 4 * BFS directory operations. 5 * Copyright (C) 1999,2000 Tigran Aivazian <tigran@veritas.com> 6 * Made endianness-clean by Andrew Stribblehill <ads@wompom.org> 2005 7 */ 8 9 #include <linux/time.h> 10 #include <linux/string.h> 11 #include <linux/fs.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, 25 int namelen, int ino); 26 static struct buffer_head *bfs_find_entry(struct inode *dir, 27 const unsigned char *name, int namelen, 28 struct bfs_dirent **res_dir); 29 30 static int bfs_readdir(struct file *f, struct dir_context *ctx) 31 { 32 struct inode *dir = file_inode(f); 33 struct buffer_head *bh; 34 struct bfs_dirent *de; 35 unsigned int offset; 36 int block; 37 38 if (ctx->pos & (BFS_DIRENT_SIZE - 1)) { 39 printf("Bad f_pos=%08lx for %s:%08lx\n", 40 (unsigned long)ctx->pos, 41 dir->i_sb->s_id, dir->i_ino); 42 return -EINVAL; 43 } 44 45 while (ctx->pos < dir->i_size) { 46 offset = ctx->pos & (BFS_BSIZE - 1); 47 block = BFS_I(dir)->i_sblock + (ctx->pos >> BFS_BSIZE_BITS); 48 bh = sb_bread(dir->i_sb, block); 49 if (!bh) { 50 ctx->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 (!dir_emit(ctx, de->name, size, 58 le16_to_cpu(de->ino), 59 DT_UNKNOWN)) { 60 brelse(bh); 61 return 0; 62 } 63 } 64 offset += BFS_DIRENT_SIZE; 65 ctx->pos += BFS_DIRENT_SIZE; 66 } while ((offset < BFS_BSIZE) && (ctx->pos < dir->i_size)); 67 brelse(bh); 68 } 69 return 0; 70 } 71 72 const struct file_operations bfs_dir_operations = { 73 .read = generic_read_dir, 74 .iterate_shared = bfs_readdir, 75 .fsync = generic_file_fsync, 76 .llseek = generic_file_llseek, 77 }; 78 79 static int bfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, 80 bool excl) 81 { 82 int err; 83 struct inode *inode; 84 struct super_block *s = dir->i_sb; 85 struct bfs_sb_info *info = BFS_SB(s); 86 unsigned long ino; 87 88 inode = new_inode(s); 89 if (!inode) 90 return -ENOMEM; 91 mutex_lock(&info->bfs_lock); 92 ino = find_first_zero_bit(info->si_imap, info->si_lasti + 1); 93 if (ino > info->si_lasti) { 94 mutex_unlock(&info->bfs_lock); 95 iput(inode); 96 return -ENOSPC; 97 } 98 set_bit(ino, info->si_imap); 99 info->si_freei--; 100 inode_init_owner(inode, dir, mode); 101 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 102 inode->i_blocks = 0; 103 inode->i_op = &bfs_file_inops; 104 inode->i_fop = &bfs_file_operations; 105 inode->i_mapping->a_ops = &bfs_aops; 106 inode->i_ino = ino; 107 BFS_I(inode)->i_dsk_ino = ino; 108 BFS_I(inode)->i_sblock = 0; 109 BFS_I(inode)->i_eblock = 0; 110 insert_inode_hash(inode); 111 mark_inode_dirty(inode); 112 bfs_dump_imap("create", s); 113 114 err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len, 115 inode->i_ino); 116 if (err) { 117 inode_dec_link_count(inode); 118 mutex_unlock(&info->bfs_lock); 119 iput(inode); 120 return err; 121 } 122 mutex_unlock(&info->bfs_lock); 123 d_instantiate(dentry, inode); 124 return 0; 125 } 126 127 static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry, 128 unsigned int flags) 129 { 130 struct inode *inode = NULL; 131 struct buffer_head *bh; 132 struct bfs_dirent *de; 133 struct bfs_sb_info *info = BFS_SB(dir->i_sb); 134 135 if (dentry->d_name.len > BFS_NAMELEN) 136 return ERR_PTR(-ENAMETOOLONG); 137 138 mutex_lock(&info->bfs_lock); 139 bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de); 140 if (bh) { 141 unsigned long ino = (unsigned long)le16_to_cpu(de->ino); 142 brelse(bh); 143 inode = bfs_iget(dir->i_sb, ino); 144 if (IS_ERR(inode)) { 145 mutex_unlock(&info->bfs_lock); 146 return ERR_CAST(inode); 147 } 148 } 149 mutex_unlock(&info->bfs_lock); 150 d_add(dentry, inode); 151 return NULL; 152 } 153 154 static int bfs_link(struct dentry *old, struct inode *dir, 155 struct dentry *new) 156 { 157 struct inode *inode = d_inode(old); 158 struct bfs_sb_info *info = BFS_SB(inode->i_sb); 159 int err; 160 161 mutex_lock(&info->bfs_lock); 162 err = bfs_add_entry(dir, new->d_name.name, new->d_name.len, 163 inode->i_ino); 164 if (err) { 165 mutex_unlock(&info->bfs_lock); 166 return err; 167 } 168 inc_nlink(inode); 169 inode->i_ctime = current_time(inode); 170 mark_inode_dirty(inode); 171 ihold(inode); 172 d_instantiate(new, inode); 173 mutex_unlock(&info->bfs_lock); 174 return 0; 175 } 176 177 static int bfs_unlink(struct inode *dir, struct dentry *dentry) 178 { 179 int error = -ENOENT; 180 struct inode *inode = d_inode(dentry); 181 struct buffer_head *bh; 182 struct bfs_dirent *de; 183 struct bfs_sb_info *info = BFS_SB(inode->i_sb); 184 185 mutex_lock(&info->bfs_lock); 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", 192 inode->i_sb->s_id, inode->i_ino, 193 inode->i_nlink); 194 set_nlink(inode, 1); 195 } 196 de->ino = 0; 197 mark_buffer_dirty_inode(bh, dir); 198 dir->i_ctime = dir->i_mtime = current_time(dir); 199 mark_inode_dirty(dir); 200 inode->i_ctime = dir->i_ctime; 201 inode_dec_link_count(inode); 202 error = 0; 203 204 out_brelse: 205 brelse(bh); 206 mutex_unlock(&info->bfs_lock); 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 unsigned int flags) 213 { 214 struct inode *old_inode, *new_inode; 215 struct buffer_head *old_bh, *new_bh; 216 struct bfs_dirent *old_de, *new_de; 217 struct bfs_sb_info *info; 218 int error = -ENOENT; 219 220 if (flags & ~RENAME_NOREPLACE) 221 return -EINVAL; 222 223 old_bh = new_bh = NULL; 224 old_inode = d_inode(old_dentry); 225 if (S_ISDIR(old_inode->i_mode)) 226 return -EINVAL; 227 228 info = BFS_SB(old_inode->i_sb); 229 230 mutex_lock(&info->bfs_lock); 231 old_bh = bfs_find_entry(old_dir, 232 old_dentry->d_name.name, 233 old_dentry->d_name.len, &old_de); 234 235 if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino)) 236 goto end_rename; 237 238 error = -EPERM; 239 new_inode = d_inode(new_dentry); 240 new_bh = bfs_find_entry(new_dir, 241 new_dentry->d_name.name, 242 new_dentry->d_name.len, &new_de); 243 244 if (new_bh && !new_inode) { 245 brelse(new_bh); 246 new_bh = NULL; 247 } 248 if (!new_bh) { 249 error = bfs_add_entry(new_dir, 250 new_dentry->d_name.name, 251 new_dentry->d_name.len, 252 old_inode->i_ino); 253 if (error) 254 goto end_rename; 255 } 256 old_de->ino = 0; 257 old_dir->i_ctime = old_dir->i_mtime = current_time(old_dir); 258 mark_inode_dirty(old_dir); 259 if (new_inode) { 260 new_inode->i_ctime = current_time(new_inode); 261 inode_dec_link_count(new_inode); 262 } 263 mark_buffer_dirty_inode(old_bh, old_dir); 264 error = 0; 265 266 end_rename: 267 mutex_unlock(&info->bfs_lock); 268 brelse(old_bh); 269 brelse(new_bh); 270 return error; 271 } 272 273 const struct inode_operations bfs_dir_inops = { 274 .create = bfs_create, 275 .lookup = bfs_lookup, 276 .link = bfs_link, 277 .unlink = bfs_unlink, 278 .rename = bfs_rename, 279 }; 280 281 static int bfs_add_entry(struct inode *dir, const unsigned char *name, 282 int namelen, int ino) 283 { 284 struct buffer_head *bh; 285 struct bfs_dirent *de; 286 int block, sblock, eblock, off, pos; 287 int i; 288 289 dprintf("name=%s, namelen=%d\n", name, namelen); 290 291 if (!namelen) 292 return -ENOENT; 293 if (namelen > BFS_NAMELEN) 294 return -ENAMETOOLONG; 295 296 sblock = BFS_I(dir)->i_sblock; 297 eblock = BFS_I(dir)->i_eblock; 298 for (block = sblock; block <= eblock; block++) { 299 bh = sb_bread(dir->i_sb, block); 300 if (!bh) 301 return -EIO; 302 for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) { 303 de = (struct bfs_dirent *)(bh->b_data + off); 304 if (!de->ino) { 305 pos = (block - sblock) * BFS_BSIZE + off; 306 if (pos >= dir->i_size) { 307 dir->i_size += BFS_DIRENT_SIZE; 308 dir->i_ctime = current_time(dir); 309 } 310 dir->i_mtime = current_time(dir); 311 mark_inode_dirty(dir); 312 de->ino = cpu_to_le16((u16)ino); 313 for (i = 0; i < BFS_NAMELEN; i++) 314 de->name[i] = 315 (i < namelen) ? name[i] : 0; 316 mark_buffer_dirty_inode(bh, dir); 317 brelse(bh); 318 return 0; 319 } 320 } 321 brelse(bh); 322 } 323 return -ENOSPC; 324 } 325 326 static inline int bfs_namecmp(int len, const unsigned char *name, 327 const char *buffer) 328 { 329 if ((len < BFS_NAMELEN) && buffer[len]) 330 return 0; 331 return !memcmp(name, buffer, len); 332 } 333 334 static struct buffer_head *bfs_find_entry(struct inode *dir, 335 const unsigned char *name, int namelen, 336 struct bfs_dirent **res_dir) 337 { 338 unsigned long block = 0, offset = 0; 339 struct buffer_head *bh = NULL; 340 struct bfs_dirent *de; 341 342 *res_dir = NULL; 343 if (namelen > BFS_NAMELEN) 344 return NULL; 345 346 while (block * BFS_BSIZE + offset < dir->i_size) { 347 if (!bh) { 348 bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block); 349 if (!bh) { 350 block++; 351 continue; 352 } 353 } 354 de = (struct bfs_dirent *)(bh->b_data + offset); 355 offset += BFS_DIRENT_SIZE; 356 if (le16_to_cpu(de->ino) && 357 bfs_namecmp(namelen, name, de->name)) { 358 *res_dir = de; 359 return bh; 360 } 361 if (offset < bh->b_size) 362 continue; 363 brelse(bh); 364 bh = NULL; 365 offset = 0; 366 block++; 367 } 368 brelse(bh); 369 return NULL; 370 } 371