commit 55aa601e14cbec987fa577a895e9297df1d0a71d
tree ed7012c8a560f39c28974518260039969548588a
parent d6ddf55440833fd9404138026af246c51ebeef22
author Phillip Susi <[EMAIL PROTECTED]> 1163668763 -0800
committer Linus Torvalds <[EMAIL PROTECTED]> 1163706218 -0800

[PATCH] Update udf documentation to reflect current state of read/write support

Change Documentation/filesystems/udf.txt from saying that read/write mounts
on cd media are not supported to instead state the current level of
support.  Specifically that it works fine on dvd+rw media and can be made
to work on cd-rw media via the pktcdvd device.

Cc: Peter Osterlund <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>

 Documentation/filesystems/udf.txt |   13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/Documentation/filesystems/udf.txt 
index 511b423..fde829a 100644
--- a/Documentation/filesystems/udf.txt
+++ b/Documentation/filesystems/udf.txt
@@ -7,8 +7,17 @@ If you encounter problems with reading U
 please report them to [EMAIL PROTECTED], 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:
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