udf: Use device size when drive reported bogus number of written blocks
Some drives report 0 as the number of written blocks when there are some blocks
recorded. Use device size in such case so that we can automagically mount such
media.
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/udf/lowlevel.c b/fs/udf/lowlevel.c
index 703843f..1b88fd5 100644
--- a/fs/udf/lowlevel.c
+++ b/fs/udf/lowlevel.c
@@ -56,7 +56,12 @@
struct block_device *bdev = sb->s_bdev;
unsigned long lblock = 0;
- if (ioctl_by_bdev(bdev, CDROM_LAST_WRITTEN, (unsigned long) &lblock))
+ /*
+ * ioctl failed or returned obviously bogus value?
+ * Try using the device size...
+ */
+ if (ioctl_by_bdev(bdev, CDROM_LAST_WRITTEN, (unsigned long) &lblock) ||
+ lblock == 0)
lblock = bdev->bd_inode->i_size >> sb->s_blocksize_bits;
if (lblock)