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authorRoot THC2026-02-24 12:42:47 +0000
committerRoot THC2026-02-24 12:42:47 +0000
commitc9cbeced5b3f2bdd7407e29c0811e65954132540 (patch)
treeaefc355416b561111819de159ccbd86c3004cf88 /other/ecfs/dir.c
parent073fe4bf9fca6bf40cef2886d75df832ef4b6fca (diff)
initial
Diffstat (limited to 'other/ecfs/dir.c')
-rw-r--r--other/ecfs/dir.c182
1 files changed, 182 insertions, 0 deletions
diff --git a/other/ecfs/dir.c b/other/ecfs/dir.c
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1/*
2 * linux/fs/ecfs/dir.c
3 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 *
9 * from
10 *
11 * linux/fs/minix/dir.c
12 *
13 * Copyright (C) 1991, 1992 Linus Torvalds
14 *
15 * ecfs directory handling functions
16 *
17 * Big-endian to little-endian byte-swapping/bitmaps by
18 * David S. Miller (davem@caip.rutgers.edu), 1995
19 */
20
21#include <linux/fs_ecfs.h>
22#include <linux/ecfs_fs.h>
23
24static unsigned char ecfs_filetype_table[] = {
25 DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
26};
27
28static int ecfs_readdir(struct file *, void *, filldir_t);
29
30struct file_operations ecfs_dir_operations = {
31 read: generic_read_dir,
32 readdir: ecfs_readdir,
33 ioctl: ecfs_ioctl,
34 fsync: ecfs_sync_file,
35};
36
37int ecfs_check_dir_entry (const char * function, struct inode * dir,
38 struct ecfs_dir_entry_2 * de,
39 struct buffer_head * bh,
40 unsigned long offset)
41{
42 const char * error_msg = NULL;
43
44 if (le16_to_cpu(de->rec_len) < ECFS_DIR_REC_LEN(1))
45 error_msg = "rec_len is smaller than minimal";
46 else if (le16_to_cpu(de->rec_len) % 4 != 0)
47 error_msg = "rec_len % 4 != 0";
48 else if (le16_to_cpu(de->rec_len) < ECFS_DIR_REC_LEN(de->name_len))
49 error_msg = "rec_len is too small for name_len";
50 else if (dir && ((char *) de - bh->b_data) + le16_to_cpu(de->rec_len) >
51 dir->i_sb->s_blocksize)
52 error_msg = "directory entry across blocks";
53 else if (dir && le32_to_cpu(de->inode) > le32_to_cpu(dir->i_sb->u.ecfs_sb.s_es->s_inodes_count))
54 error_msg = "inode out of bounds";
55
56 if (error_msg != NULL)
57 ecfs_error (dir->i_sb, function, "bad entry in directory #%lu: %s - "
58 "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
59 dir->i_ino, error_msg, offset,
60 (unsigned long) le32_to_cpu(de->inode),
61 le16_to_cpu(de->rec_len), de->name_len);
62 return error_msg == NULL ? 1 : 0;
63}
64
65static int ecfs_readdir(struct file * filp,
66 void * dirent, filldir_t filldir)
67{
68 int error = 0;
69 unsigned long offset, blk;
70 int i, num, stored;
71 struct buffer_head * bh, * tmp, * bha[16];
72 struct ecfs_dir_entry_2 * de;
73 struct super_block * sb;
74 int err;
75 struct inode *inode = filp->f_dentry->d_inode;
76
77 sb = inode->i_sb;
78
79 stored = 0;
80 bh = NULL;
81 offset = filp->f_pos & (sb->s_blocksize - 1);
82
83 while (!error && !stored && filp->f_pos < inode->i_size) {
84 blk = (filp->f_pos) >> ECFS_BLOCK_SIZE_BITS(sb);
85 bh = ecfs_bread (inode, blk, 0, &err);
86 if (!bh) {
87 ecfs_error (sb, "ecfs_readdir",
88 "directory #%lu contains a hole at offset %lu",
89 inode->i_ino, (unsigned long)filp->f_pos);
90 filp->f_pos += sb->s_blocksize - offset;
91 continue;
92 }
93
94 /*
95 * Do the readahead
96 */
97 if (!offset) {
98 for (i = 16 >> (ECFS_BLOCK_SIZE_BITS(sb) - 9), num = 0;
99 i > 0; i--) {
100 tmp = ecfs_getblk (inode, ++blk, 0, &err);
101 if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
102 bha[num++] = tmp;
103 else
104 brelse (tmp);
105 }
106 if (num) {
107 ll_rw_block (READA, num, bha);
108 for (i = 0; i < num; i++)
109 brelse (bha[i]);
110 }
111 }
112
113revalidate:
114 /* If the dir block has changed since the last call to
115 * readdir(2), then we might be pointing to an invalid
116 * dirent right now. Scan from the start of the block
117 * to make sure. */
118 if (filp->f_version != inode->i_version) {
119 for (i = 0; i < sb->s_blocksize && i < offset; ) {
120 de = (struct ecfs_dir_entry_2 *)
121 (bh->b_data + i);
122 /* It's too expensive to do a full
123 * dirent test each time round this
124 * loop, but we do have to test at
125 * least that it is non-zero. A
126 * failure will be detected in the
127 * dirent test below. */
128 if (le16_to_cpu(de->rec_len) < ECFS_DIR_REC_LEN(1))
129 break;
130 i += le16_to_cpu(de->rec_len);
131 }
132 offset = i;
133 filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
134 | offset;
135 filp->f_version = inode->i_version;
136 }
137
138 while (!error && filp->f_pos < inode->i_size
139 && offset < sb->s_blocksize) {
140 de = (struct ecfs_dir_entry_2 *) (bh->b_data + offset);
141 if (!ecfs_check_dir_entry ("ecfs_readdir", inode, de,
142 bh, offset)) {
143 /* On error, skip the f_pos to the
144 next block. */
145 filp->f_pos = (filp->f_pos | (sb->s_blocksize - 1))
146 + 1;
147 brelse (bh);
148 return stored;
149 }
150 offset += le16_to_cpu(de->rec_len);
151 if (le32_to_cpu(de->inode)) {
152 /* We might block in the next section
153 * if the data destination is
154 * currently swapped out. So, use a
155 * version stamp to detect whether or
156 * not the directory has been modified
157 * during the copy operation.
158 */
159 unsigned long version = filp->f_version;
160 unsigned char d_type = DT_UNKNOWN;
161
162 if (ECFS_HAS_INCOMPAT_FEATURE(sb, ECFS_FEATURE_INCOMPAT_FILETYPE)
163 && de->file_type < ECFS_FT_MAX)
164 d_type = ecfs_filetype_table[de->file_type];
165 error = filldir(dirent, de->name,
166 de->name_len,
167 filp->f_pos, le32_to_cpu(de->inode),
168 d_type);
169 if (error)
170 break;
171 if (version != filp->f_version)
172 goto revalidate;
173 stored ++;
174 }
175 filp->f_pos += le16_to_cpu(de->rec_len);
176 }
177 offset = 0;
178 brelse (bh);
179 }
180 UPDATE_ATIME(inode);
181 return 0;
182}