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/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 }