| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 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 = 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 | /* 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 | |