xref: /OK3568_Linux_fs/kernel/Documentation/filesystems/udf.rst (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun.. SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun
3*4882a593Smuzhiyun===============
4*4882a593SmuzhiyunUDF file system
5*4882a593Smuzhiyun===============
6*4882a593Smuzhiyun
7*4882a593SmuzhiyunIf you encounter problems with reading UDF discs using this driver,
8*4882a593Smuzhiyunplease report them according to MAINTAINERS file.
9*4882a593Smuzhiyun
10*4882a593SmuzhiyunWrite support requires a block driver which supports writing.  Currently
11*4882a593Smuzhiyundvd+rw drives and media support true random sector writes, and so a udf
12*4882a593Smuzhiyunfilesystem on such devices can be directly mounted read/write.  CD-RW
13*4882a593Smuzhiyunmedia however, does not support this.  Instead the media can be formatted
14*4882a593Smuzhiyunfor packet mode using the utility cdrwtool, then the pktcdvd driver can
15*4882a593Smuzhiyunbe bound to the underlying cd device to provide the required buffering
16*4882a593Smuzhiyunand read-modify-write cycles to allow the filesystem random sector writes
17*4882a593Smuzhiyunwhile providing the hardware with only full packet writes.  While not
18*4882a593Smuzhiyunrequired for dvd+rw media, use of the pktcdvd driver often enhances
19*4882a593Smuzhiyunperformance due to very poor read-modify-write support supplied internally
20*4882a593Smuzhiyunby drive firmware.
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun-------------------------------------------------------------------------------
23*4882a593Smuzhiyun
24*4882a593SmuzhiyunThe following mount options are supported:
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun	===========	======================================
27*4882a593Smuzhiyun	gid=		Set the default group.
28*4882a593Smuzhiyun	umask=		Set the default umask.
29*4882a593Smuzhiyun	mode=		Set the default file permissions.
30*4882a593Smuzhiyun	dmode=		Set the default directory permissions.
31*4882a593Smuzhiyun	uid=		Set the default user.
32*4882a593Smuzhiyun	bs=		Set the block size.
33*4882a593Smuzhiyun	unhide		Show otherwise hidden files.
34*4882a593Smuzhiyun	undelete	Show deleted files in lists.
35*4882a593Smuzhiyun	adinicb		Embed data in the inode (default)
36*4882a593Smuzhiyun	noadinicb	Don't embed data in the inode
37*4882a593Smuzhiyun	shortad		Use short ad's
38*4882a593Smuzhiyun	longad		Use long ad's (default)
39*4882a593Smuzhiyun	nostrict	Unset strict conformance
40*4882a593Smuzhiyun	iocharset=	Set the NLS character set
41*4882a593Smuzhiyun	===========	======================================
42*4882a593Smuzhiyun
43*4882a593SmuzhiyunThe uid= and gid= options need a bit more explaining.  They will accept a
44*4882a593Smuzhiyundecimal numeric value and all inodes on that mount will then appear as
45*4882a593Smuzhiyunbelonging to that uid and gid.  Mount options also accept the string "forget".
46*4882a593SmuzhiyunThe forget option causes all IDs to be written to disk as -1 which is a way
47*4882a593Smuzhiyunof UDF standard to indicate that IDs are not supported for these files .
48*4882a593Smuzhiyun
49*4882a593SmuzhiyunFor typical desktop use of removable media, you should set the ID to that of
50*4882a593Smuzhiyunthe interactively logged on user, and also specify the forget option.  This way
51*4882a593Smuzhiyunthe interactive user will always see the files on the disk as belonging to him.
52*4882a593Smuzhiyun
53*4882a593SmuzhiyunThe remaining are for debugging and disaster recovery:
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun	=====		================================
56*4882a593Smuzhiyun	novrs		Skip volume sequence recognition
57*4882a593Smuzhiyun	=====		================================
58*4882a593Smuzhiyun
59*4882a593SmuzhiyunThe following expect a offset from 0.
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun	==========	=================================================
62*4882a593Smuzhiyun	session=	Set the CDROM session (default= last session)
63*4882a593Smuzhiyun	anchor=		Override standard anchor location. (default= 256)
64*4882a593Smuzhiyun	lastblock=	Set the last block of the filesystem/
65*4882a593Smuzhiyun	==========	=================================================
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun-------------------------------------------------------------------------------
68*4882a593Smuzhiyun
69*4882a593Smuzhiyun
70*4882a593SmuzhiyunFor the latest version and toolset see:
71*4882a593Smuzhiyun	https://github.com/pali/udftools
72*4882a593Smuzhiyun
73*4882a593SmuzhiyunDocumentation on UDF and ECMA 167 is available FREE from:
74*4882a593Smuzhiyun	- http://www.osta.org/
75*4882a593Smuzhiyun	- https://www.ecma-international.org/
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