dir.c

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    1 /*
    2  * Copyright 2000-2002 by Hans Reiser, licensing governed by reiserfs/README
    3  */
    4 
    5 #include <linux/config.h>
    6 #include <linux/string.h>
    7 #include <linux/errno.h>
    8 #include <linux/fs.h>
    9 #include <linux/reiserfs_fs.h>
   10 #include <linux/stat.h>
   11 #include <linux/smp_lock.h>
   12 #include <asm/uaccess.h>
   13 
   14 extern struct key  MIN_KEY;
   15 
   16 static int reiserfs_readdir (struct file *, void *, filldir_t);
   17 int reiserfs_dir_fsync(struct file *filp, struct dentry *dentry, int datasync) ;
   18 
   19 struct file_operations reiserfs_dir_operations = {
   20     read:       generic_read_dir,
   21     readdir:    reiserfs_readdir,
   22     fsync:      reiserfs_dir_fsync,
   23     ioctl:      reiserfs_ioctl,
   24 };
   25 
   26 int reiserfs_dir_fsync(struct file *filp, struct dentry *dentry, int datasync) {
   27   lock_kernel();
   28   reiserfs_commit_for_inode(dentry->d_inode) ;
   29   unlock_kernel() ;
   30   return 0 ;
   31 }
   32 
   33 
   34 #define store_ih(where,what) copy_item_head (where, what)
   35 
   36 //
   37 static int reiserfs_readdir (struct file * filp, void * dirent, filldir_t filldir)
   38 {
   39     struct inode *inode = filp->f_dentry->d_inode;
   40     struct cpu_key pos_key;     /* key of current position in the directory (key of directory entry) */
   41     INITIALIZE_PATH (path_to_entry);
   42     struct buffer_head * bh;
   43     int item_num, entry_num;
   44     const struct key * rkey;
   45     struct item_head * ih, tmp_ih;
   46     int search_res;
   47     char * local_buf;
   48     loff_t next_pos;
   49     char small_buf[32] ; /* avoid kmalloc if we can */
   50     struct reiserfs_dir_entry de;
   51 
   52 
   53     reiserfs_check_lock_depth("readdir") ;
   54 
   55     /* form key for search the next directory entry using f_pos field of
   56        file structure */
   57     make_cpu_key (&pos_key, inode, (filp->f_pos) ? (filp->f_pos) : DOT_OFFSET,
   58                   TYPE_DIRENTRY, 3);
   59     next_pos = cpu_key_k_offset (&pos_key);
   60 
   61     /*  reiserfs_warning (inode->i_sb, "reiserfs_readdir 1: f_pos = %Ld\n", filp->f_pos);*/
   62 
   63     while (1) {
   64     research:
   65         /* search the directory item, containing entry with specified key */
   66         search_res = search_by_entry_key (inode->i_sb, &pos_key, &path_to_entry, &de);
   67         if (search_res == IO_ERROR) {
   68             // FIXME: we could just skip part of directory which could
   69             // not be read
   70             return -EIO;
   71         }
   72         entry_num = de.de_entry_num;
   73         bh = de.de_bh;
   74         item_num = de.de_item_num;
   75         ih = de.de_ih;
   76         store_ih (&tmp_ih, ih);
   77                 
   78         /* we must have found item, that is item of this directory, */
   79         RFALSE( COMP_SHORT_KEYS (&(ih->ih_key), &pos_key),
   80                 "vs-9000: found item %h does not match to dir we readdir %K",
   81                 ih, &pos_key);
   82         RFALSE( item_num > B_NR_ITEMS (bh) - 1,
   83                 "vs-9005 item_num == %d, item amount == %d", 
   84                 item_num, B_NR_ITEMS (bh));
   85       
   86         /* and entry must be not more than number of entries in the item */
   87         RFALSE( I_ENTRY_COUNT (ih) < entry_num,
   88                 "vs-9010: entry number is too big %d (%d)", 
   89                 entry_num, I_ENTRY_COUNT (ih));
   90 
   91         if (search_res == POSITION_FOUND || entry_num < I_ENTRY_COUNT (ih)) {
   92             /* go through all entries in the directory item beginning from the entry, that has been found */
   93             struct reiserfs_de_head * deh = B_I_DEH (bh, ih) + entry_num;
   94 
   95             for (; entry_num < I_ENTRY_COUNT (ih); entry_num ++, deh ++) {
   96                 int d_reclen;
   97                 char * d_name;
   98                 off_t d_off;
   99                 ino_t d_ino;
  100 
  101                 if (!de_visible (deh))
  102                     /* it is hidden entry */
  103                     continue;
  104                 d_reclen = entry_length (bh, ih, entry_num);
  105                 d_name = B_I_DEH_ENTRY_FILE_NAME (bh, ih, deh);
  106                 if (!d_name[d_reclen - 1])
  107                     d_reclen = strlen (d_name);
  108         
  109                 if (d_reclen > REISERFS_MAX_NAME(inode->i_sb->s_blocksize)){
  110                     /* too big to send back to VFS */
  111                     continue ;
  112                 }
  113                 d_off = deh_offset (deh);
  114                 filp->f_pos = d_off ;
  115                 d_ino = deh_objectid (deh);
  116                 if (d_reclen <= 32) {
  117                   local_buf = small_buf ;
  118                 } else {
  119                     local_buf = reiserfs_kmalloc(d_reclen, GFP_NOFS, inode->i_sb) ;
  120                     if (!local_buf) {
  121                         pathrelse (&path_to_entry);
  122                         return -ENOMEM ;
  123                     }
  124                     if (item_moved (&tmp_ih, &path_to_entry)) {
  125                         reiserfs_kfree(local_buf, d_reclen, inode->i_sb) ;
  126                         goto research;
  127                     }
  128                 }
  129                 // Note, that we copy name to user space via temporary
  130                 // buffer (local_buf) because filldir will block if
  131                 // user space buffer is swapped out. At that time
  132                 // entry can move to somewhere else
  133                 memcpy (local_buf, d_name, d_reclen);
  134                 if (filldir (dirent, local_buf, d_reclen, d_off, d_ino, 
  135                              DT_UNKNOWN) < 0) {
  136                     if (local_buf != small_buf) {
  137                         reiserfs_kfree(local_buf, d_reclen, inode->i_sb) ;
  138                     }
  139                     goto end;
  140                 }
  141                 if (local_buf != small_buf) {
  142                     reiserfs_kfree(local_buf, d_reclen, inode->i_sb) ;
  143                 }
  144 
  145                 // next entry should be looked for with such offset
  146                 next_pos = deh_offset (deh) + 1;
  147 
  148                 if (item_moved (&tmp_ih, &path_to_entry)) {
  149                     goto research;
  150                 }
  151             } /* for */
  152         }
  153 
  154         if (item_num != B_NR_ITEMS (bh) - 1)
  155             // end of directory has been reached
  156             goto end;
  157 
  158         /* item we went through is last item of node. Using right
  159            delimiting key check is it directory end */
  160         rkey = get_rkey (&path_to_entry, inode->i_sb);
  161         if (! comp_le_keys (rkey, &MIN_KEY)) {
  162             /* set pos_key to key, that is the smallest and greater
  163                that key of the last entry in the item */
  164             set_cpu_key_k_offset (&pos_key, next_pos);
  165             continue;
  166         }
  167 
  168         if ( COMP_SHORT_KEYS (rkey, &pos_key)) {
  169             // end of directory has been reached
  170             goto end;
  171         }
  172         
  173         /* directory continues in the right neighboring block */
  174         set_cpu_key_k_offset (&pos_key, le_key_k_offset (KEY_FORMAT_3_5, rkey));
  175 
  176     } /* while */
  177 
  178 
  179  end:
  180 
  181     filp->f_pos = next_pos;
  182     pathrelse (&path_to_entry);
  183     reiserfs_check_path(&path_to_entry) ;
  184     UPDATE_ATIME(inode) ;
  185     return 0;
  186 }
  187 
  188 /* compose directory item containing "." and ".." entries (entries are
  189    not aligned to 4 byte boundary) */
  190 /* the last four params are LE */
  191 void make_empty_dir_item_v1 (char * body, __u32 dirid, __u32 objid,
  192                              __u32 par_dirid, __u32 par_objid)
  193 {
  194     struct reiserfs_de_head * deh;
  195 
  196     memset (body, 0, EMPTY_DIR_SIZE_V1);
  197     deh = (struct reiserfs_de_head *)body;
  198     
  199     /* direntry header of "." */
  200     put_deh_offset( &(deh[0]), DOT_OFFSET );
  201     /* these two are from make_le_item_head, and are are LE */
  202     deh[0].deh_dir_id = dirid;
  203     deh[0].deh_objectid = objid;
  204     deh[0].deh_state = 0; /* Endian safe if 0 */
  205     put_deh_location( &(deh[0]), EMPTY_DIR_SIZE_V1 - strlen( "." ));
  206     mark_de_visible(&(deh[0]));
  207   
  208     /* direntry header of ".." */
  209     put_deh_offset( &(deh[1]), DOT_DOT_OFFSET);
  210     /* key of ".." for the root directory */
  211     /* these two are from the inode, and are are LE */
  212     deh[1].deh_dir_id = par_dirid;
  213     deh[1].deh_objectid = par_objid;
  214     deh[1].deh_state = 0; /* Endian safe if 0 */
  215     put_deh_location( &(deh[1]), deh_location( &(deh[0]) ) - strlen( ".." ) );
  216     mark_de_visible(&(deh[1]));
  217 
  218     /* copy ".." and "." */
  219     memcpy (body + deh_location( &(deh[0]) ), ".", 1);
  220     memcpy (body + deh_location( &(deh[1]) ), "..", 2);
  221 }
  222 
  223 /* compose directory item containing "." and ".." entries */
  224 void make_empty_dir_item (char * body, __u32 dirid, __u32 objid,
  225                           __u32 par_dirid, __u32 par_objid)
  226 {
  227     struct reiserfs_de_head * deh;
  228 
  229     memset (body, 0, EMPTY_DIR_SIZE);
  230     deh = (struct reiserfs_de_head *)body;
  231     
  232     /* direntry header of "." */
  233     put_deh_offset( &(deh[0]), DOT_OFFSET );
  234     /* these two are from make_le_item_head, and are are LE */
  235     deh[0].deh_dir_id = dirid;
  236     deh[0].deh_objectid = objid;
  237     deh[0].deh_state = 0; /* Endian safe if 0 */
  238     put_deh_location( &(deh[0]), EMPTY_DIR_SIZE - ROUND_UP( strlen( "." ) ) );
  239     mark_de_visible(&(deh[0]));
  240   
  241     /* direntry header of ".." */
  242     put_deh_offset( &(deh[1]), DOT_DOT_OFFSET );
  243     /* key of ".." for the root directory */
  244     /* these two are from the inode, and are are LE */
  245     deh[1].deh_dir_id = par_dirid;
  246     deh[1].deh_objectid = par_objid;
  247     deh[1].deh_state = 0; /* Endian safe if 0 */
  248     put_deh_location( &(deh[1]), deh_location( &(deh[0])) - ROUND_UP( strlen( ".." ) ) );
  249     mark_de_visible(&(deh[1]));
  250 
  251     /* copy ".." and "." */
  252     memcpy (body + deh_location( &(deh[0]) ), ".", 1);
  253     memcpy (body + deh_location( &(deh[1]) ), "..", 2);
  254 }

Cache object: a96a54913e93a5316d3d02efa66921fb

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FreeBSD/Linux Kernel Cross Reference sys/fs/reiserfs/dir.c

FreeBSD/Linux Kernel Cross Reference
sys/fs/reiserfs/dir.c