jfs_debugfs(8)
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 sub
- command 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_num
- ber> 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/