From: Eric Sandeen There's a bug where a UDF_PART_FLAG_READ_ONLY udf partition gets mounted read-write, then subsequent problems happen; files seem to be able to be removed, but file creation results in EIO or worse, oops. EIO is coming from udf_new_block(), which returns EIO if the right flags aren't set; only UDF_PART_FLAG_READ_ONLY is set in this case. We probably s hould not have gotten this far... Attached patch seems to fix it - and includes a printk to alert the user that their "rw" mount request has been converted to "ro." Here's the testcase I used: [root@magnesium ~]# mkisofs -R -J -udf -o testiso /tmp/ ... Total translation table size: 0 Total rockridge attributes bytes: 342923 Total directory bytes: 382312 Path table size(bytes): 104 Max brk space used 103000 105059 extents written (205 MB) [root@magnesium ~]# mount -o loop testiso /mnt/test/ [root@magnesium ~]# ls /mnt/test/fsfile /mnt/test/fsfile [root@magnesium ~]# rm /mnt/test/fsfile [root@magnesium ~]# ls /mnt/test/fsfile ls: /mnt/test/fsfile: No such file or directory [root@magnesium ~]# touch /mnt/test/fsfile touch: cannot touch `/mnt/test/fsfile': Input/output error [root@magnesium tmp]# grep udf /proc/mounts /dev/loop1 /mnt/test udf rw 0 0 Force readonly mounts of UDF partitions marked as read-only. Signed-off-by: Eric Sandeen Signed-off-by: Andrew Morton --- fs/udf/super.c | 4 ++++ 1 file changed, 4 insertions(+) diff -puN fs/udf/super.c~mount-udf-udf_part_flag_read_only-partitions-with-ms_rdonly fs/udf/super.c --- a/fs/udf/super.c~mount-udf-udf_part_flag_read_only-partitions-with-ms_rdonly +++ a/fs/udf/super.c @@ -1622,6 +1622,10 @@ static int udf_fill_super(struct super_b goto error_out; } + if (UDF_SB_PARTFLAGS(sb, UDF_SB_PARTITION(sb)) & UDF_PART_FLAG_READ_ONLY) + printk("UDF-fs: Partition marked readonly; forcing readonly mount\n"); + sb->s_flags |= MS_RDONLY; + if ( udf_find_fileset(sb, &fileset, &rootdir) ) { printk("UDF-fs: No fileset found\n"); _