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
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
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
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
cb[blfsck]
displays the area used by ClearBadBlockList for communication
with fsck
SUBCOMMANDS:
m => modify entries
x => exit subcommand mode
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
SUBCOMMANDS:
m => modify entries
x => exit subcommand mode
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
dm[ap] displays aggregate disk (block) map
SUBCOMMANDS
m => modify map fields
f => display free count
t => display tree levels
x => exit subcommand mode
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
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
fsckw[sphdr]
displays the header of the fsck workspace in the aggregate
SUBCOMMANDS:
m => modify entries
x => exit subcommand mode
h[elp] [<command>]
displays help for <command>
if no command is given, all possible commands are displayed
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
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[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
SUBCOMMANDS
a => display/modify inode’s ACL
m => modify inode
x => exit subcommand mode
logs[uper]
displays the journal log superblock and enters subcommand mode
SUBCOMMANDS
m => modify journal log superblock
x => exit subcommand mode
q[uit] exits jfs_debugfs
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
su[perblock] [p | s]
displays superblock data
p displays the primary superblock
s displays the secondary superblock
SUBCOMMANDS:
m => modify entries
x => exit subcommand mode
s2p[erblock] [p | s]
displays alternate superblock data
p displays the primary superblock
s displays the secondary superblock
SUBCOMMANDS:
m => modify entries
x => exit subcommand mode
u[nset] <variable>
* not implemented yet *
deletes user-defined <variable>
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
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 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
jfs_fsck(8), jfs_mkfs(8), jfs_fscklog(8), jfs_logdump(8), jfs_tune(8),
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/
October 29, 2002 jfs_debugfs(8)