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 obdfs_check_dir_entry (const char * function, struct inode * dir,
53 struct ext2_dir_entry_2 * de,
57 const char * error_msg = NULL;
61 error_msg = "null de passed";
65 if (le16_to_cpu(de->rec_len) < EXT2_DIR_REC_LEN(1))
66 error_msg = "rec_len is smaller than minimal";
67 else if (le16_to_cpu(de->rec_len) % 4 != 0)
68 error_msg = "rec_len % 4 != 0";
69 else if (le16_to_cpu(de->rec_len) < EXT2_DIR_REC_LEN(de->name_len))
70 error_msg = "rec_len is too small for name_len";
71 else if (dir && ((char *) de - (char *)page_address(page)) + le16_to_cpu(de->rec_len) >
72 dir->i_sb->s_blocksize)
73 error_msg = "directory entry across blocks";
74 #if 0 /* this one doesn't yet work for OBDFS */
77 if (dir && le32_to_cpu(de->inode) > le32_to_cpu(dir->i_sb->u.ext2_sb.s_es->s_inodes_count))
78 error_msg = "inode out of bounds";
80 if (error_msg != NULL)
81 ext2_error (dir->i_sb, function, "bad entry in directory #%lu: %s - "
82 "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
83 dir->i_ino, error_msg, offset,
84 (unsigned long) le32_to_cpu(de->inode),
85 le16_to_cpu(de->rec_len), de->name_len);
87 return error_msg == NULL ? 1 : 0;
91 int obdfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
96 struct ext2_dir_entry_2 * de;
97 struct super_block * sb;
99 struct inode *inode = filp->f_dentry->d_inode;
106 offset = filp->f_pos & (PAGE_SIZE - 1);
108 while (!error && !stored && filp->f_pos < inode->i_size) {
109 page = obdfs_getpage(inode, offset, 0, NOLOCK);
110 PDEBUG(page, "readdir");
112 ext2_error (sb, "ext2_readdir",
113 "directory #%lu contains a hole at offset %lu",
114 inode->i_ino, (unsigned long)filp->f_pos);
115 filp->f_pos += PAGE_SIZE - offset;
120 /* XXX need to do read ahead and support stuff below */
122 /* If the dir block has changed since the last call to
123 * readdir(2), then we might be pointing to an invalid
124 * dirent right now. Scan from the start of the block
126 if (filp->f_version != inode->i_version) {
127 for (i = 0; i < sb->s_blocksize && i < offset; ) {
128 de = (struct ext2_dir_entry_2 *)
130 /* It's too expensive to do a full
131 * dirent test each time round this
132 * loop, but we do have to test at
133 * least that it is non-zero. A
134 * failure will be detected in the
135 * dirent test below. */
136 if (le16_to_cpu(de->rec_len) < EXT2_DIR_REC_LEN(1))
138 i += le16_to_cpu(de->rec_len);
141 filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
143 filp->f_version = inode->i_version;
146 while (!error && filp->f_pos < inode->i_size
147 && offset < PAGE_SIZE) {
148 de = (struct ext2_dir_entry_2 *) ((char *)page_address(page) + offset);
150 if (!obdfs_check_dir_entry ("ext2_readdir", inode, de,
152 /* On error, skip the f_pos to the
154 filp->f_pos = (filp->f_pos & (sb->s_blocksize - 1))
160 offset += le16_to_cpu(de->rec_len);
161 if (le32_to_cpu(de->inode)) {
162 /* We might block in the next section
163 * if the data destination is
164 * currently swapped out. So, use a
165 * version stamp to detect whether or
166 * not the directory has been modified
167 * during the copy operation.
169 /* XXX unsigned long version = inode->i_version;
171 error = filldir(dirent, de->name,
173 filp->f_pos, le32_to_cpu(de->inode));
177 if (version != inode->i_version)
182 filp->f_pos += le16_to_cpu(de->rec_len);
185 page_cache_release(page);