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)
11 * linux/fs/minix/dir.c
13 * Copyright (C) 1991, 1992 Linus Torvalds
15 * ext2 directory handling functions
17 * Big-endian to little-endian byte-swapping/bitmaps by
18 * David S. Miller (davem@caip.rutgers.edu), 1995
20 * Changes for use with Object Based Device File System
22 * Copyright (C) 1999, Seagate Technology Inc.
23 * (author Peter J. Braam, braam@stelias.com)
27 #include <asm/uaccess.h>
29 #include <asm/uaccess.h>
31 #include <linux/errno.h>
33 #include <linux/ext2_fs.h>
34 #include <linux/fcntl.h>
35 #include <linux/sched.h>
36 #include <linux/stat.h>
37 #include <linux/string.h>
38 #include <linux/locks.h>
39 #include <linux/quotaops.h>
40 #include <linux/iobuf.h>
42 #include <linux/obd_support.h>
45 static ssize_t obdfs_dir_read (struct file * filp, char * buf,
46 size_t count, loff_t *ppos)
52 int ext2_check_dir_entry (const char * function, struct inode * dir,
53 struct ext2_dir_entry_2 * de,
54 struct buffer_head * bh,
57 const char * error_msg = NULL;
59 if (le16_to_cpu(de->rec_len) < EXT2_DIR_REC_LEN(1))
60 error_msg = "rec_len is smaller than minimal";
61 else if (le16_to_cpu(de->rec_len) % 4 != 0)
62 error_msg = "rec_len % 4 != 0";
63 else if (le16_to_cpu(de->rec_len) < EXT2_DIR_REC_LEN(de->name_len))
64 error_msg = "rec_len is too small for name_len";
65 else if (dir && ((char *) de - bh->b_data) + le16_to_cpu(de->rec_len) >
66 dir->i_sb->s_blocksize)
67 error_msg = "directory entry across blocks";
68 else if (dir && le32_to_cpu(de->inode) > le32_to_cpu(dir->i_sb->u.ext2_sb.s_es->s_inodes_count))
69 error_msg = "inode out of bounds";
71 if (error_msg != NULL)
72 ext2_error (dir->i_sb, function, "bad entry in directory #%lu: %s - "
73 "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
74 dir->i_ino, error_msg, offset,
75 (unsigned long) le32_to_cpu(de->inode),
76 le16_to_cpu(de->rec_len), de->name_len);
77 return error_msg == NULL ? 1 : 0;
82 int obdfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
87 struct ext2_dir_entry_2 * de;
88 struct super_block * sb;
90 struct inode *inode = filp->f_dentry->d_inode;
95 offset = filp->f_pos & (PAGE_SIZE - 1);
97 while (!error && !stored && filp->f_pos < inode->i_size) {
98 page = obdfs_getpage(inode, offset);
100 ext2_error (sb, "ext2_readdir",
101 "directory #%lu contains a hole at offset %lu",
102 inode->i_ino, (unsigned long)filp->f_pos);
103 filp->f_pos += PAGE_SIZE - offset;
108 /* XXX need to do read ahead and support stuff below */
110 /* If the dir block has changed since the last call to
111 * readdir(2), then we might be pointing to an invalid
112 * dirent right now. Scan from the start of the block
114 if (filp->f_version != inode->i_version) {
115 for (i = 0; i < sb->s_blocksize && i < offset; ) {
116 de = (struct ext2_dir_entry_2 *)
118 /* It's too expensive to do a full
119 * dirent test each time round this
120 * loop, but we do have to test at
121 * least that it is non-zero. A
122 * failure will be detected in the
123 * dirent test below. */
124 if (le16_to_cpu(de->rec_len) < EXT2_DIR_REC_LEN(1))
126 i += le16_to_cpu(de->rec_len);
129 filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
131 filp->f_version = inode->i_version;
134 while (!error && filp->f_pos < inode->i_size
135 && offset < PAGE_SIZE) {
136 de = (struct ext2_dir_entry_2 *) ((char *)page_address(page) + offset);
138 if (!obdfs_check_dir_entry ("ext2_readdir", inode, de,
140 /* On error, skip the f_pos to the
142 filp->f_pos = (filp->f_pos & (sb->s_blocksize - 1))
148 offset += le16_to_cpu(de->rec_len);
149 if (le32_to_cpu(de->inode)) {
150 /* We might block in the next section
151 * if the data destination is
152 * currently swapped out. So, use a
153 * version stamp to detect whether or
154 * not the directory has been modified
155 * during the copy operation.
157 /* XXX unsigned long version = inode->i_version;
159 error = filldir(dirent, de->name,
161 filp->f_pos, le32_to_cpu(de->inode));
165 if (version != inode->i_version)
170 filp->f_pos += le16_to_cpu(de->rec_len);