NAME
jfs_debugfs
- shell-type JFS file system editor
SYNOPSIS
jfs_debugfs
device
DESCRIPTION
jfs_debugfs
is a program which can be used to perform various low-level actions on a JFS formatted device.
device
is the special file name corresponding to the actual device to be edited
(e.g. /dev/hdb1).
jfs_debugfs
must be run as root.
COMMANDS
I a[lter] <block> <offset> <hex_string>
replaces the data located at the
<offset>
of
<block>
with
<hex_string>
<block>
is the block number - given in decimal
<offset>
is the offset within that block - given in hexadecimal
<hex_string>
is an even-numbered string of hexadecimal digits to write to the disk
I b[tree] <block> [<offset>]
* not implemented yet *
displays one node of the btree located at
<offset>
of
<block>
and enters a subcommand mode to navigate the btree
I SUBCOMMANDS:
l => visit left sibling
m => modify current node
p => visit parent node
r => visit right sibling
[0-9] => visit the n'th child node
x => exit subcommand mode
I cb[blfsck]
displays the area used by ClearBadBlockList for communication with fsck
I SUBCOMMANDS:
m => modify entries
x => exit subcommand mode
I dir[ectory] <inode_number> [<file_set>]
displays the directory entries at
<inode_number>
and enters subcommand mode
<inode_number>
is the directory's inode - given in decimal
<file_set>
currently must be zero
I SUBCOMMANDS:
m => modify entries
x => exit subcommand mode
I d[isplay] [<block> [<offset> [<format> [<count>]]]]
displays
<count>
objects located at the
<offset>
of
<block>
in
<format>
<block>
is the block number - given in decimal
<offset>
is the offset within
<block>
- given in hexadecimal
<format>
is one of the following:
a => ascii
b => block allocation map
d => decimal
i => inode
I => inode allocation map
s => superblock
x => hexadecimal
X => extent allocation descriptor
<count>
is the number of objects to display - given in decimal
I dm[ap]
displays aggregate disk (block) map
I SUBCOMMANDS
m => modify map fields
f => display free count
t => display tree levels
x => exit subcommand mode
I dt[ree] <inode_number> [<file_set>]
displays root of the directory btree located at
<inode_number>
and enters a subcommand mode to navigate the btree
<inode_number>
is the directory's inode - given in decimal
<file_set>
currently must be zero
I SUBCOMMANDS
l => visit left sibling
m => modify current node
p => visit parent node (not parent directory)
r => visit right sibling
[0-9] => visit the n'th child node
x => exit subcommand mode
I fsckw[sphdr]
displays the header of the fsck workspace in the aggregate
I SUBCOMMANDS:
m => modify entries
x => exit subcommand mode
I h[elp] [<command>]
displays help for
<command>
if no command is given, all possible commands are displayed
I ia[g] [<IAG_number>] [a | s | <file_set>]
displays IAG information for
<IAG_number>
and enters subcommand mode
<IAG_number>
is given in decimal
a
is to use the primary aggregate inode table
s
is to use the secondary aggregate inode table
<file_set>
currently must be zero
I SUBCOMMANDS
e => display/modify inode extents map
m => modify IAG
p => display/modify persistent map
w => display/modify working map
x => exit subcommand mode
I i[node] [<inode_number>] [a | s | <file_set>]
displays inode information for
<inode_number>
and enters subcommand mode
<inode_number>
is given in decimal
a
is to use the primary aggregate inode table
s
is to use the secondary aggregate inode table
<file_set>
currently must be zero
I SUBCOMMANDS
a => display/modify inode's ACL
m => modify inode
x => exit subcommand mode
I logs[uper]
displays the journal log superblock and enters subcommand mode
I SUBCOMMANDS
m => modify journal log superblock
x => exit subcommand mode
I q[uit]
exits jfs_debugfs
I se[t] [<variable> <value>]
* not implemented yet *
set user-defined
<variable>
to
<value>
if no arguments are given, displays all set variables
<variable>
must begin with an alphabetic character
I su[perblock] [p | s]
displays superblock data
p
displays the primary superblock
s
displays the secondary superblock
I SUBCOMMANDS:
m => modify entries
x => exit subcommand mode
I s2p[erblock] [p | s]
displays alternate superblock data
p
displays the primary superblock
s
displays the secondary superblock
I SUBCOMMANDS:
m => modify entries
x => exit subcommand mode
I u[nset] <variable>
* not implemented yet *
deletes user-defined
<variable>
I xt[ree] <inode_number> [<file_set>]
displays root of the non-directory btree located at
<inode_number>
and enters a subcommand mode to navigate the btree
<inode_number>
is the directory's inode - given in decimal
<file_set>
currently must be zero
I SUBCOMMANDS
l => visit left sibling
m => modify current node
p => visit parent node (not parent directory)
r => visit right sibling
[0-9] => visit the n'th child node
x => exit subcommand mode
REPORTING BUGS
If you find a bug in
JFS
or
R jfs_debugfs ,
please report it via the bug tracking system ("Report Bugs" section) of the JFS project web site:
http://jfs.sourceforge.net/
Please send as much pertinent information as possible, including the complete output of running
jfs_fsck
with the
-v
and
-n
options on the JFS device.
SEE ALSO
AUTHORS
Barry Arndt (barndt@us.ibm.com)
William Braswell, Jr.
jfs_debugfs
is maintained by IBM.
See the JFS project web site for more details:
http://jfs.sourceforge.net/