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diff --git a/Documentation/filesystems/udf.rst b/Documentation/filesystems/udf.rst new file mode 100644 index 000000000..f9489ddbb --- /dev/null +++ b/Documentation/filesystems/udf.rst @@ -0,0 +1,75 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============== +UDF file system +=============== + +If you encounter problems with reading UDF discs using this driver, +please report them according to MAINTAINERS file. + +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. + undelete Show deleted files in lists. + adinicb Embed data in the inode (default) + noadinicb Don't embed data in the inode + shortad Use short ad's + longad Use long ad's (default) + nostrict Unset strict conformance + iocharset= Set the NLS character set + =========== ====================================== + +The uid= and gid= options need a bit more explaining. They will accept a +decimal numeric value and all inodes on that mount will then appear as +belonging to that uid and gid. Mount options also accept the string "forget". +The forget option causes all IDs to be written to disk as -1 which is a way +of UDF standard to indicate that IDs are not supported for these files . + +For typical desktop use of removable media, you should set the ID to that of +the interactively logged on user, and also specify the forget option. This way +the interactive user will always see the files on the disk as belonging to him. + +The remaining are for debugging and disaster recovery: + + ===== ================================ + novrs Skip volume sequence recognition + ===== ================================ + +The following expect a offset from 0. + + ========== ================================================= + session= Set the CDROM session (default= last session) + anchor= Override standard anchor location. (default= 256) + lastblock= Set the last block of the filesystem/ + ========== ================================================= + +------------------------------------------------------------------------------- + + +For the latest version and toolset see: + https://github.com/pali/udftools + +Documentation on UDF and ECMA 167 is available FREE from: + - http://www.osta.org/ + - https://www.ecma-international.org/ |