diff --git a/[refs] b/[refs]
index c4d56d7224e3..b7603e77aa49 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: d6ddf55440833fd9404138026af246c51ebeef22
+refs/heads/master: 55aa601e14cbec987fa577a895e9297df1d0a71d
diff --git a/trunk/Documentation/filesystems/udf.txt b/trunk/Documentation/filesystems/udf.txt
index 511b4230c053..fde829a756e6 100644
--- a/trunk/Documentation/filesystems/udf.txt
+++ b/trunk/Documentation/filesystems/udf.txt
@@ -7,8 +7,17 @@ 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: