Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[pandora-kernel.git] / Documentation / filesystems / udf.txt

diff --git a/Documentation/filesystems/udf.txt b/Documentation/filesystems/udf.txt
index 511b423..902b95d 100644 (file)
--- a/Documentation/filesystems/udf.txt
+++ b/Documentation/filesystems/udf.txt
@@ -7,14 +7,25 @@ If you encounter problems with reading UDF discs using this driver,
 please report them to linux_udf@hpesjro.fc.hp.com, which is the
 developer's list.
 
-Write support requires a block driver which supports writing. The current
-scsi and ide cdrom drivers do not support writing.
+Write support requires a block driver which supports writing.  Currently
+dvd+rw drives and media support true random sector writes, and so a udf
+filesystem on such devices can be directly mounted read/write.  CD-RW
+media however, does not support this.  Instead the media can be formatted
+for packet mode using the utility cdrwtool, then the pktcdvd driver can
+be bound to the underlying cd device to provide the required buffering
+and read-modify-write cycles to allow the filesystem random sector writes
+while providing the hardware with only full packet writes.  While not
+required for dvd+rw media, use of the pktcdvd driver often enhances
+performance due to very poor read-modify-write support supplied internally
+by drive firmware.
 
 -------------------------------------------------------------------------------
 The following mount options are supported:
 
        gid=            Set the default group.
        umask=          Set the default umask.
+       mode=           Set the default file permissions.
+       dmode=          Set the default directory permissions.
        uid=            Set the default user.
        bs=             Set the block size.
        unhide          Show otherwise hidden files.