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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/affs/dir.c
3 *
4 * (c) 1996 Hans-Joachim Widmaier - Rewritten
5 *
6 * (C) 1993 Ray Burr - Modified for Amiga FFS filesystem.
7 *
8 * (C) 1992 Eric Youngdale Modified for ISO 9660 filesystem.
9 *
10 * (C) 1991 Linus Torvalds - minix filesystem
11 *
12 * affs directory handling functions
13 *
14 */
15
16#include "affs.h"
17
Al Viro0edf9772013-05-17 17:44:42 -040018static int affs_readdir(struct file *, struct dir_context *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070019
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -080020const struct file_operations affs_dir_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070021 .read = generic_read_dir,
Al Viro59af1582008-08-24 07:24:41 -040022 .llseek = generic_file_llseek,
Al Viro0edf9772013-05-17 17:44:42 -040023 .iterate = affs_readdir,
Al Viroc4758792009-06-08 01:22:00 -040024 .fsync = affs_file_fsync,
Linus Torvalds1da177e2005-04-16 15:20:36 -070025};
26
27/*
28 * directories can handle most operations...
29 */
Arjan van de Ven754661f2007-02-12 00:55:38 -080030const struct inode_operations affs_dir_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070031 .create = affs_create,
32 .lookup = affs_lookup,
33 .link = affs_link,
34 .unlink = affs_unlink,
35 .symlink = affs_symlink,
36 .mkdir = affs_mkdir,
37 .rmdir = affs_rmdir,
38 .rename = affs_rename,
39 .setattr = affs_notify_change,
40};
41
42static int
Al Viro0edf9772013-05-17 17:44:42 -040043affs_readdir(struct file *file, struct dir_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -070044{
Al Viro0edf9772013-05-17 17:44:42 -040045 struct inode *inode = file_inode(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 struct super_block *sb = inode->i_sb;
Al Viro0edf9772013-05-17 17:44:42 -040047 struct buffer_head *dir_bh = NULL;
48 struct buffer_head *fh_bh = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -070049 unsigned char *name;
50 int namelen;
51 u32 i;
52 int hash_pos;
53 int chain_pos;
Linus Torvalds1da177e2005-04-16 15:20:36 -070054 u32 ino;
Linus Torvalds1da177e2005-04-16 15:20:36 -070055
Al Viro0edf9772013-05-17 17:44:42 -040056 pr_debug("AFFS: readdir(ino=%lu,f_pos=%lx)\n",inode->i_ino,(unsigned long)ctx->pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -070057
Al Viro0edf9772013-05-17 17:44:42 -040058 if (ctx->pos < 2) {
59 file->private_data = (void *)0;
60 if (!dir_emit_dots(file, ctx))
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 }
63
64 affs_lock_dir(inode);
Al Viro0edf9772013-05-17 17:44:42 -040065 chain_pos = (ctx->pos - 2) & 0xffff;
66 hash_pos = (ctx->pos - 2) >> 16;
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 if (chain_pos == 0xffff) {
68 affs_warning(sb, "readdir", "More than 65535 entries in chain");
69 chain_pos = 0;
70 hash_pos++;
Al Viro0edf9772013-05-17 17:44:42 -040071 ctx->pos = ((hash_pos << 16) | chain_pos) + 2;
Linus Torvalds1da177e2005-04-16 15:20:36 -070072 }
73 dir_bh = affs_bread(sb, inode->i_ino);
74 if (!dir_bh)
75 goto readdir_out;
76
77 /* If the directory hasn't changed since the last call to readdir(),
78 * we can jump directly to where we left off.
79 */
Al Viro0edf9772013-05-17 17:44:42 -040080 ino = (u32)(long)file->private_data;
81 if (ino && file->f_version == inode->i_version) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070082 pr_debug("AFFS: readdir() left off=%d\n", ino);
83 goto inside;
84 }
85
86 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);
87 for (i = 0; ino && i < chain_pos; i++) {
88 fh_bh = affs_bread(sb, ino);
89 if (!fh_bh) {
90 affs_error(sb, "readdir","Cannot read block %d", i);
Al Viro0edf9772013-05-17 17:44:42 -040091 return -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 }
93 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
94 affs_brelse(fh_bh);
95 fh_bh = NULL;
96 }
97 if (ino)
98 goto inside;
99 hash_pos++;
100
101 for (; hash_pos < AFFS_SB(sb)->s_hashsize; hash_pos++) {
102 ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[hash_pos]);
103 if (!ino)
104 continue;
Al Viro0edf9772013-05-17 17:44:42 -0400105 ctx->pos = (hash_pos << 16) + 2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106inside:
107 do {
108 fh_bh = affs_bread(sb, ino);
109 if (!fh_bh) {
110 affs_error(sb, "readdir","Cannot read block %d", ino);
Al Viro0edf9772013-05-17 17:44:42 -0400111 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 }
113
114 namelen = min(AFFS_TAIL(sb, fh_bh)->name[0], (u8)30);
115 name = AFFS_TAIL(sb, fh_bh)->name + 1;
116 pr_debug("AFFS: readdir(): filldir(\"%.*s\", ino=%u), hash=%d, f_pos=%x\n",
Al Viro0edf9772013-05-17 17:44:42 -0400117 namelen, name, ino, hash_pos, (u32)ctx->pos);
118 if (!dir_emit(ctx, name, namelen, ino, DT_UNKNOWN))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 goto readdir_done;
Al Viro0edf9772013-05-17 17:44:42 -0400120 ctx->pos++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 ino = be32_to_cpu(AFFS_TAIL(sb, fh_bh)->hash_chain);
122 affs_brelse(fh_bh);
123 fh_bh = NULL;
124 } while (ino);
125 }
126readdir_done:
Al Viro0edf9772013-05-17 17:44:42 -0400127 file->f_version = inode->i_version;
128 file->private_data = (void *)(long)ino;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129
130readdir_out:
131 affs_brelse(dir_bh);
132 affs_brelse(fh_bh);
133 affs_unlock_dir(inode);
Al Viro0edf9772013-05-17 17:44:42 -0400134 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135}