1 /* 2 * dir.c 3 * 4 * Copyright (c) 1999 Al Smith 5 */ 6 7 #include <linux/buffer_head.h> 8 #include "efs.h" 9 10 static int efs_readdir(struct file *, void *, filldir_t); 11 12 const struct file_operations efs_dir_operations = { 13 .llseek = generic_file_llseek, 14 .read = generic_read_dir, 15 .readdir = efs_readdir, 16 }; 17 18 const struct inode_operations efs_dir_inode_operations = { 19 .lookup = efs_lookup, 20 }; 21 22 static int efs_readdir(struct file *filp, void *dirent, filldir_t filldir) { 23 struct inode *inode = file_inode(filp); 24 struct buffer_head *bh; 25 26 struct efs_dir *dirblock; 27 struct efs_dentry *dirslot; 28 efs_ino_t inodenum; 29 efs_block_t block; 30 int slot, namelen; 31 char *nameptr; 32 33 if (inode->i_size & (EFS_DIRBSIZE-1)) 34 printk(KERN_WARNING "EFS: WARNING: readdir(): directory size not a multiple of EFS_DIRBSIZE\n"); 35 36 /* work out where this entry can be found */ 37 block = filp->f_pos >> EFS_DIRBSIZE_BITS; 38 39 /* each block contains at most 256 slots */ 40 slot = filp->f_pos & 0xff; 41 42 /* look at all blocks */ 43 while (block < inode->i_blocks) { 44 /* read the dir block */ 45 bh = sb_bread(inode->i_sb, efs_bmap(inode, block)); 46 47 if (!bh) { 48 printk(KERN_ERR "EFS: readdir(): failed to read dir block %d\n", block); 49 break; 50 } 51 52 dirblock = (struct efs_dir *) bh->b_data; 53 54 if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) { 55 printk(KERN_ERR "EFS: readdir(): invalid directory block\n"); 56 brelse(bh); 57 break; 58 } 59 60 while (slot < dirblock->slots) { 61 if (dirblock->space[slot] == 0) { 62 slot++; 63 continue; 64 } 65 66 dirslot = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot)); 67 68 inodenum = be32_to_cpu(dirslot->inode); 69 namelen = dirslot->namelen; 70 nameptr = dirslot->name; 71 72 #ifdef DEBUG 73 printk(KERN_DEBUG "EFS: readdir(): block %d slot %d/%d: inode %u, name \"%s\", namelen %u\n", block, slot, dirblock->slots-1, inodenum, nameptr, namelen); 74 #endif 75 if (namelen > 0) { 76 /* found the next entry */ 77 filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot; 78 79 /* copy filename and data in dirslot */ 80 filldir(dirent, nameptr, namelen, filp->f_pos, inodenum, DT_UNKNOWN); 81 82 /* sanity check */ 83 if (nameptr - (char *) dirblock + namelen > EFS_DIRBSIZE) { 84 printk(KERN_WARNING "EFS: directory entry %d exceeds directory block\n", slot); 85 slot++; 86 continue; 87 } 88 89 /* store position of next slot */ 90 if (++slot == dirblock->slots) { 91 slot = 0; 92 block++; 93 } 94 brelse(bh); 95 filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot; 96 goto out; 97 } 98 slot++; 99 } 100 brelse(bh); 101 102 slot = 0; 103 block++; 104 } 105 106 filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot; 107 out: 108 return 0; 109 } 110 111