1 /* 2 * dir.c 3 * 4 * Copyright (c) 1999 Al Smith 5 */ 6 7 #include <linux/buffer_head.h> 8 #include <linux/smp_lock.h> 9 #include "efs.h" 10 11 static int efs_readdir(struct file *, void *, filldir_t); 12 13 const struct file_operations efs_dir_operations = { 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 = filp->f_path.dentry->d_inode; 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 lock_kernel(); 37 38 /* work out where this entry can be found */ 39 block = filp->f_pos >> EFS_DIRBSIZE_BITS; 40 41 /* each block contains at most 256 slots */ 42 slot = filp->f_pos & 0xff; 43 44 /* look at all blocks */ 45 while (block < inode->i_blocks) { 46 /* read the dir block */ 47 bh = sb_bread(inode->i_sb, efs_bmap(inode, block)); 48 49 if (!bh) { 50 printk(KERN_ERR "EFS: readdir(): failed to read dir block %d\n", block); 51 break; 52 } 53 54 dirblock = (struct efs_dir *) bh->b_data; 55 56 if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) { 57 printk(KERN_ERR "EFS: readdir(): invalid directory block\n"); 58 brelse(bh); 59 break; 60 } 61 62 while (slot < dirblock->slots) { 63 if (dirblock->space[slot] == 0) { 64 slot++; 65 continue; 66 } 67 68 dirslot = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot)); 69 70 inodenum = be32_to_cpu(dirslot->inode); 71 namelen = dirslot->namelen; 72 nameptr = dirslot->name; 73 74 #ifdef DEBUG 75 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); 76 #endif 77 if (namelen > 0) { 78 /* found the next entry */ 79 filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot; 80 81 /* copy filename and data in dirslot */ 82 filldir(dirent, nameptr, namelen, filp->f_pos, inodenum, DT_UNKNOWN); 83 84 /* sanity check */ 85 if (nameptr - (char *) dirblock + namelen > EFS_DIRBSIZE) { 86 printk(KERN_WARNING "EFS: directory entry %d exceeds directory block\n", slot); 87 slot++; 88 continue; 89 } 90 91 /* store position of next slot */ 92 if (++slot == dirblock->slots) { 93 slot = 0; 94 block++; 95 } 96 brelse(bh); 97 filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot; 98 goto out; 99 } 100 slot++; 101 } 102 brelse(bh); 103 104 slot = 0; 105 block++; 106 } 107 108 filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot; 109 out: 110 unlock_kernel(); 111 return 0; 112 } 113 114