Merge remote-tracking branch 'asoc/topic/simple' into asoc-next
[linux-2.6-block.git] / Documentation / filesystems / udf.txt
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1*
2* Documentation/filesystems/udf.txt
3*
4UDF Filesystem version 0.9.8.1
5
6If you encounter problems with reading UDF discs using this driver,
7please report them to linux_udf@hpesjro.fc.hp.com, which is the
8developer's list.
9
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10Write support requires a block driver which supports writing. Currently
11dvd+rw drives and media support true random sector writes, and so a udf
12filesystem on such devices can be directly mounted read/write. CD-RW
13media however, does not support this. Instead the media can be formatted
14for packet mode using the utility cdrwtool, then the pktcdvd driver can
15be bound to the underlying cd device to provide the required buffering
16and read-modify-write cycles to allow the filesystem random sector writes
17while providing the hardware with only full packet writes. While not
18required for dvd+rw media, use of the pktcdvd driver often enhances
19performance due to very poor read-modify-write support supplied internally
20by drive firmware.
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21
22-------------------------------------------------------------------------------
23The following mount options are supported:
24
25 gid= Set the default group.
26 umask= Set the default umask.
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27 mode= Set the default file permissions.
28 dmode= Set the default directory permissions.
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29 uid= Set the default user.
30 bs= Set the block size.
31 unhide Show otherwise hidden files.
32 undelete Show deleted files in lists.
33 adinicb Embed data in the inode (default)
34 noadinicb Don't embed data in the inode
35 shortad Use short ad's
36 longad Use long ad's (default)
37 nostrict Unset strict conformance
38 iocharset= Set the NLS character set
39
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40The uid= and gid= options need a bit more explaining. They will accept a
41decimal numeric value which will be used as the default ID for that mount.
42They will also accept the string "ignore" and "forget". For files on the disk
43that are owned by nobody ( -1 ), they will instead look as if they are owned
44by the default ID. The ignore option causes the default ID to override all
45IDs on the disk, not just -1. The forget option causes all IDs to be written
46to disk as -1, so when the media is later remounted, they will appear to be
47owned by whatever default ID it is mounted with at that time.
48
49For typical desktop use of removable media, you should set the ID to that
50of the interactively logged on user, and also specify both the forget and
51ignore options. This way the interactive user will always see the files
52on the disk as belonging to him.
53
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54The remaining are for debugging and disaster recovery:
55
56 novrs Skip volume sequence recognition
57
58The following expect a offset from 0.
59
60 session= Set the CDROM session (default= last session)
61 anchor= Override standard anchor location. (default= 256)
62 volume= Override the VolumeDesc location. (unused)
63 partition= Override the PartitionDesc location. (unused)
64 lastblock= Set the last block of the filesystem/
65
66The following expect a offset from the partition root.
67
68 fileset= Override the fileset block location. (unused)
69 rootdir= Override the root directory location. (unused)
70 WARNING: overriding the rootdir to a non-directory may
71 yield highly unpredictable results.
72-------------------------------------------------------------------------------
73
74
75For the latest version and toolset see:
76 http://linux-udf.sourceforge.net/
77
78Documentation on UDF and ECMA 167 is available FREE from:
79 http://www.osta.org/
80 http://www.ecma-international.org/
81
82Ben Fennema <bfennema@falcon.csc.calpoly.edu>