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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * dir.c
3 *
4 * Copyright (c) 1999 Al Smith
5 */
6
7#include <linux/buffer_head.h>
Christoph Hellwig45254b42008-02-23 15:23:51 -08008#include "efs.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -07009
Al Viro7aa123a2013-05-16 01:41:10 -040010static int efs_readdir(struct file *, struct dir_context *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070011
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -080012const struct file_operations efs_dir_operations = {
Al Viroe7ec9522009-06-16 23:35:46 -040013 .llseek = generic_file_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -070014 .read = generic_read_dir,
Al Viroc51da202016-04-30 22:37:34 -040015 .iterate_shared = efs_readdir,
Linus Torvalds1da177e2005-04-16 15:20:36 -070016};
17
Arjan van de Ven754661f2007-02-12 00:55:38 -080018const struct inode_operations efs_dir_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070019 .lookup = efs_lookup,
20};
21
Al Viro7aa123a2013-05-16 01:41:10 -040022static int efs_readdir(struct file *file, struct dir_context *ctx)
23{
24 struct inode *inode = file_inode(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -070025 efs_block_t block;
Al Viro7aa123a2013-05-16 01:41:10 -040026 int slot;
Linus Torvalds1da177e2005-04-16 15:20:36 -070027
28 if (inode->i_size & (EFS_DIRBSIZE-1))
Fabian Frederickf403d1d2014-06-04 16:12:12 -070029 pr_warn("%s(): directory size not a multiple of EFS_DIRBSIZE\n",
30 __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -070031
Linus Torvalds1da177e2005-04-16 15:20:36 -070032 /* work out where this entry can be found */
Al Viro7aa123a2013-05-16 01:41:10 -040033 block = ctx->pos >> EFS_DIRBSIZE_BITS;
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
35 /* each block contains at most 256 slots */
Al Viro7aa123a2013-05-16 01:41:10 -040036 slot = ctx->pos & 0xff;
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
38 /* look at all blocks */
39 while (block < inode->i_blocks) {
Al Viro7aa123a2013-05-16 01:41:10 -040040 struct efs_dir *dirblock;
41 struct buffer_head *bh;
42
Linus Torvalds1da177e2005-04-16 15:20:36 -070043 /* read the dir block */
44 bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
45
46 if (!bh) {
Fabian Frederickf403d1d2014-06-04 16:12:12 -070047 pr_err("%s(): failed to read dir block %d\n",
48 __func__, block);
Linus Torvalds1da177e2005-04-16 15:20:36 -070049 break;
50 }
51
52 dirblock = (struct efs_dir *) bh->b_data;
53
54 if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
Fabian Frederickf403d1d2014-06-04 16:12:12 -070055 pr_err("%s(): invalid directory block\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 brelse(bh);
57 break;
58 }
59
Al Viro7aa123a2013-05-16 01:41:10 -040060 for (; slot < dirblock->slots; slot++) {
61 struct efs_dentry *dirslot;
62 efs_ino_t inodenum;
63 const char *nameptr;
64 int namelen;
65
66 if (dirblock->space[slot] == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -070068
69 dirslot = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
70
71 inodenum = be32_to_cpu(dirslot->inode);
72 namelen = dirslot->namelen;
73 nameptr = dirslot->name;
Fabian Frederickd1826f22014-06-04 16:12:13 -070074 pr_debug("%s(): block %d slot %d/%d: inode %u, name \"%s\", namelen %u\n",
75 __func__, block, slot, dirblock->slots-1,
76 inodenum, nameptr, namelen);
Al Viro7aa123a2013-05-16 01:41:10 -040077 if (!namelen)
78 continue;
79 /* found the next entry */
80 ctx->pos = (block << EFS_DIRBSIZE_BITS) | slot;
Linus Torvalds1da177e2005-04-16 15:20:36 -070081
Al Viro7aa123a2013-05-16 01:41:10 -040082 /* sanity check */
83 if (nameptr - (char *) dirblock + namelen > EFS_DIRBSIZE) {
Fabian Frederickf403d1d2014-06-04 16:12:12 -070084 pr_warn("directory entry %d exceeds directory block\n",
85 slot);
Al Viro7aa123a2013-05-16 01:41:10 -040086 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 }
Al Viro7aa123a2013-05-16 01:41:10 -040088
89 /* copy filename and data in dirslot */
90 if (!dir_emit(ctx, nameptr, namelen, inodenum, DT_UNKNOWN)) {
91 brelse(bh);
92 return 0;
93 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 }
95 brelse(bh);
96
97 slot = 0;
98 block++;
99 }
Al Viro7aa123a2013-05-16 01:41:10 -0400100 ctx->pos = (block << EFS_DIRBSIZE_BITS) | slot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 return 0;
102}