We have found a problem with readdir() for isofs. When there are a lot of files in a single directory, and when you copy that directory, some of the files can disappear. For example, we found this with the Windows 2000 CD-ROM.
After looking into it, it seems that there is a boundary error in linux/fs/isofs/dir.c. When the sector size is 2048 and the directory entry offset is also 2048, there is a problem.
When de_len, the sum of the buffer start address plus the offset becomes 2048 and *de_len is zero, then it skips one sector and you there fore skip some files.
Please look at the patch I have included for details.
--- linux/fs/isofs/dir.c.orig Sat Apr 24 13:20:38 1999
+++ linux/fs/isofs/dir.c Fri Jul 21 02:37:16 2000
@@ -160,9 +163,11 @@
de = (struct iso_directory_record *) (bh->b_data + offset);
if(first_de) inode_number = (block << bufbits) + (offset & (bufs
ize - 1));
- de_len = *(unsigned char *) de;
+ /* Check boundaries and get length. by GO! */
+ if (offset < bufsize) de_len = *(unsigned char *) de;
#ifdef DEBUG
- printk("de_len = %ld\n", de_len);
+ if (offset < bufsize) printk("de_len = %ld\n", de_len);
+ else printk("Move to next sector\n");
#endif
@@ -170,15 +175,15 @@
CDROM sector. If we are at the end of the directory, we
kick out of the while loop. */
- if ((de_len == 0) || (offset >= bufsize) ) {
+ if ((offset >= bufsize) || (de_len == 0) ) {
brelse(bh);
- if (de_len == 0) {
+ if (offset >= bufsize) { /*Check first. by GO!*/
+ offset -= bufsize;
+ filp->f_pos += offset;
+ } else {
filp->f_pos = ((filp->f_pos & ~(ISOFS_BLOCK_SIZE
- 1))
+ ISOFS_BLOCK_SIZE);
offset = 0;
- } else {
- offset -= bufsize;
- filp->f_pos += offset;
}
if (filp->f_pos >= inode->i_size)
-
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This archive was generated by hypermail 2b29 : Sun Jul 23 2000 - 21:00:15 EST