fs/bfs/dir.c

   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/time.h>
   8 #include <linux/string.h>
   9 #include <linux/fs.h>
  10 #include <linux/smp_lock.h>
  11 #include <linux/buffer_head.h>
  12 #include <linux/sched.h>
  13 #include "bfs.h"
  14
  15 #undef DEBUG
  16
  17 #ifdef DEBUG
  18 #define dprintf(x...)   printf(x)
  19 #else
  20 #define dprintf(x...)
  21 #endif
  22
  23 static int bfs_add_entry(struct inode * dir, const char * name, int namelen, int ino);
  24 static struct buffer_head * bfs_find_entry(struct inode * dir,
  25         const char * name, int namelen, struct bfs_dirent ** res_dir);
  26
  27 static int bfs_readdir(struct file * f, void * dirent, filldir_t filldir)
  28 {
  29         struct inode * dir = f->f_dentry->d_inode;
  30         struct buffer_head * bh;
  31         struct bfs_dirent * de;
  32         unsigned int offset;
  33         int block;
  34
  35         lock_kernel();
  36
  37         if (f->f_pos & (BFS_DIRENT_SIZE-1)) {
  38                 printf("Bad f_pos=%08lx for %s:%08lx\n", (unsigned long)f->f_pos,
  39                         dir->i_sb->s_id, dir->i_ino);
  40                 unlock_kernel();
  41                 return -EBADF;
  42         }
  43
  44         while (f->f_pos < dir->i_size) {
  45                 offset = f->f_pos & (BFS_BSIZE-1);
  46                 block = BFS_I(dir)->i_sblock + (f->f_pos >> BFS_BSIZE_BITS);
  47                 bh = sb_bread(dir->i_sb, block);
  48                 if (!bh) {
  49                         f->f_pos += BFS_BSIZE - offset;
  50                         continue;
  51                 }
  52                 do {
  53                         de = (struct bfs_dirent *)(bh->b_data + offset);
  54                         if (de->ino) {
  55                                 int size = strnlen(de->name, BFS_NAMELEN);
  56                                 if (filldir(dirent, de->name, size, f->f_pos, de->ino, DT_UNKNOWN) < 0) {
  57                                         brelse(bh);
  58                                         unlock_kernel();
  59                                         return 0;
  60                                 }
  61                         }
  62                         offset += BFS_DIRENT_SIZE;
  63                         f->f_pos += BFS_DIRENT_SIZE;
  64                 } while (offset < BFS_BSIZE && f->f_pos < dir->i_size);
  65                 brelse(bh);
  66         }
  67
  68         unlock_kernel();
  69         return 0;
  70 }
  71
  72 struct file_operations bfs_dir_operations = {
  73         .read           = generic_read_dir,
  74         .readdir        = bfs_readdir,
  75         .fsync          = file_fsync,
  76 };
  77
  78 extern void dump_imap(const char *, struct super_block *);
  79
  80 static int bfs_create(struct inode * dir, struct dentry * dentry, int mode,
  81                 struct nameidata *nd)
  82 {
  83         int err;
  84         struct inode * inode;
  85         struct super_block * s = dir->i_sb;
  86         struct bfs_sb_info * info = BFS_SB(s);
  87         unsigned long ino;
  88
  89         inode = new_inode(s);
  90         if (!inode)
  91                 return -ENOSPC;
  92         lock_kernel();
  93         ino = find_first_zero_bit(info->si_imap, info->si_lasti);
  94         if (ino > info->si_lasti) {
  95                 unlock_kernel();
  96                 iput(inode);
  97                 return -ENOSPC;
  98         }
  99         set_bit(ino, info->si_imap);
 100         info->si_freei--;
 101         inode->i_uid = current->fsuid;
 102         inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid;
 103         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
 104         inode->i_blocks = inode->i_blksize = 0;
 105         inode->i_op = &bfs_file_inops;
 106         inode->i_fop = &bfs_file_operations;
 107         inode->i_mapping->a_ops = &bfs_aops;
 108         inode->i_mode = mode;
 109         inode->i_ino = ino;
 110         BFS_I(inode)->i_dsk_ino = ino;
 111         BFS_I(inode)->i_sblock = 0;
 112         BFS_I(inode)->i_eblock = 0;
 113         insert_inode_hash(inode);
 114         mark_inode_dirty(inode);
 115         dump_imap("create",s);
 116
 117         err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len, inode->i_ino);
 118         if (err) {
 119                 inode->i_nlink--;
 120                 mark_inode_dirty(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 = le32_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         inode->i_nlink++;
 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 || 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_nlink--;
 199         inode->i_ctime = dir->i_ctime;
 200         mark_inode_dirty(inode);
 201         error = 0;
 202
 203 out_brelse:
 204         brelse(bh);
 205         unlock_kernel();
 206         return error;
 207 }
 208
 209 static int bfs_rename(struct inode * old_dir, struct dentry * old_dentry,
 210                         struct inode * new_dir, struct dentry * new_dentry)
 211 {
 212         struct inode * old_inode, * new_inode;
 213         struct buffer_head * old_bh, * new_bh;
 214         struct bfs_dirent * old_de, * new_de;
 215         int error = -ENOENT;
 216
 217         old_bh = new_bh = NULL;
 218         old_inode = old_dentry->d_inode;
 219         if (S_ISDIR(old_inode->i_mode))
 220                 return -EINVAL;
 221
 222         lock_kernel();
 223         old_bh = bfs_find_entry(old_dir,
 224                                 old_dentry->d_name.name,
 225                                 old_dentry->d_name.len, &old_de);
 226
 227         if (!old_bh || old_de->ino != old_inode->i_ino)
 228                 goto end_rename;
 229
 230         error = -EPERM;
 231         new_inode = new_dentry->d_inode;
 232         new_bh = bfs_find_entry(new_dir,
 233                                 new_dentry->d_name.name,
 234                                 new_dentry->d_name.len, &new_de);
 235
 236         if (new_bh && !new_inode) {
 237                 brelse(new_bh);
 238                 new_bh = NULL;
 239         }
 240         if (!new_bh) {
 241                 error = bfs_add_entry(new_dir,
 242                                         new_dentry->d_name.name,
 243                                         new_dentry->d_name.len, old_inode->i_ino);
 244                 if (error)
 245                         goto end_rename;
 246         }
 247         old_de->ino = 0;
 248         old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
 249         mark_inode_dirty(old_dir);
 250         if (new_inode) {
 251                 new_inode->i_nlink--;
 252                 new_inode->i_ctime = CURRENT_TIME_SEC;
 253                 mark_inode_dirty(new_inode);
 254         }
 255         mark_buffer_dirty(old_bh);
 256         error = 0;
 257
 258 end_rename:
 259         unlock_kernel();
 260         brelse(old_bh);
 261         brelse(new_bh);
 262         return error;
 263 }
 264
 265 struct inode_operations bfs_dir_inops = {
 266         .create                 = bfs_create,
 267         .lookup                 = bfs_lookup,
 268         .link                   = bfs_link,
 269         .unlink                 = bfs_unlink,
 270         .rename                 = bfs_rename,
 271 };
 272
 273 static int bfs_add_entry(struct inode * dir, const char * name, int namelen, int ino)
 274 {
 275         struct buffer_head * bh;
 276         struct bfs_dirent * de;
 277         int block, sblock, eblock, off, eoff;
 278         int i;
 279
 280         dprintf("name=%s, namelen=%d\n", name, namelen);
 281
 282         if (!namelen)
 283                 return -ENOENT;
 284         if (namelen > BFS_NAMELEN)
 285                 return -ENAMETOOLONG;
 286
 287         sblock = BFS_I(dir)->i_sblock;
 288         eblock = BFS_I(dir)->i_eblock;
 289         eoff = dir->i_size % BFS_BSIZE;
 290         for (block=sblock; block<=eblock; block++) {
 291                 bh = sb_bread(dir->i_sb, block);
 292                 if(!bh)
 293                         return -ENOSPC;
 294                 for (off=0; off<BFS_BSIZE; off+=BFS_DIRENT_SIZE) {
 295                         de = (struct bfs_dirent *)(bh->b_data + off);
 296                         if (block==eblock && off>=eoff) {
 297                                 /* Do not read/interpret the garbage in the end of eblock. */
 298                                 de->ino = 0;
 299                         }
 300                         if (!de->ino) {
 301                                 if ((block-sblock)*BFS_BSIZE + off >= dir->i_size) {
 302                                         dir->i_size += BFS_DIRENT_SIZE;
 303                                         dir->i_ctime = CURRENT_TIME_SEC;
 304                                 }
 305                                 dir->i_mtime = CURRENT_TIME_SEC;
 306                                 mark_inode_dirty(dir);
 307                                 de->ino = ino;
 308                                 for (i=0; i<BFS_NAMELEN; i++)
 309                                         de->name[i] = (i < namelen) ? name[i] : 0;
 310                                 mark_buffer_dirty(bh);
 311                                 brelse(bh);
 312                                 return 0;
 313                         }
 314                 }
 315                 brelse(bh);
 316         }
 317         return -ENOSPC;
 318 }
 319
 320 static inline int bfs_namecmp(int len, const char * name, const char * buffer)
 321 {
 322         if (len < BFS_NAMELEN && buffer[len])
 323                 return 0;
 324         return !memcmp(name, buffer, len);
 325 }
 326
 327 static struct buffer_head * bfs_find_entry(struct inode * dir,
 328         const char * name, int namelen, struct bfs_dirent ** res_dir)
 329 {
 330         unsigned long block, offset;
 331         struct buffer_head * bh;
 332         struct bfs_dirent * de;
 333
 334         *res_dir = NULL;
 335         if (namelen > BFS_NAMELEN)
 336                 return NULL;
 337         bh = NULL;
 338         block = offset = 0;
 339         while (block * BFS_BSIZE + offset < dir->i_size) {
 340                 if (!bh) {
 341                         bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
 342                         if (!bh) {
 343                                 block++;
 344                                 continue;
 345                         }
 346                 }
 347                 de = (struct bfs_dirent *)(bh->b_data + offset);
 348                 offset += BFS_DIRENT_SIZE;
 349                 if (de->ino && bfs_namecmp(namelen, name, de->name)) {
 350                         *res_dir = de;
 351                         return bh;
 352                 }
 353                 if (offset < bh->b_size)
 354                         continue;
 355                 brelse(bh);
 356                 bh = NULL;
 357                 offset = 0;
 358                 block++;
 359         }
 360         brelse(bh);
 361         return NULL;
 362 }