.TH jfs_debugfs 8 "October 29, 2002" " " "JFS file system editor"

.SH NAME
.B jfs_debugfs
\- shell-type JFS file system editor

.SH SYNOPSIS
.B jfs_debugfs
.I device

.SH DESCRIPTION
.PP
.B jfs_debugfs
is a program which can be used to perform various low-level actions on a JFS formatted device.
.PP
.I device
is the special file name corresponding to the actual device to be edited
.RB (e.g. " /dev/hdb1" ).
.PP
.B jfs_debugfs
must be run as root.

.SH COMMANDS
.TP
.BI a[lter] " <block> <offset> <hex_string>"
 replaces the data located at the
.I <offset>
of
.I <block>
with
.I <hex_string>

.I <block>
is the block number - given in decimal

.I <offset>
is the offset within that block - given in hexadecimal

.I <hex_string>
is an even-numbered string of hexadecimal digits to write to the disk

.TP
.BI b[tree] " <block> [<offset>]"
.B * not implemented yet *
 displays one node of the btree located at
.I <offset>
of
.I <block>
and enters a subcommand mode to navigate the btree

.BI 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

.TP
.BI cb[blfsck]
 displays the area used by ClearBadBlockList for communication with fsck

.BI SUBCOMMANDS:
 m => modify entries
 x => exit subcommand mode

.TP
.BI dir[ectory] " <inode_number> [<file_set>]"
 displays the directory entries at
.I <inode_number>
and enters subcommand mode

.I <inode_number>
is the directory's inode - given in decimal

.I <file_set>
currently must be zero

.BI SUBCOMMANDS:
 m => modify entries
 x => exit subcommand mode

.TP
.BI d[isplay] " [<block> [<offset> [<format> [<count>]]]]"
displays
.I <count>
objects located at the
.I <offset>
of
.I <block>
in
.I <format>

.I <block>
is the block number - given in decimal

.I <offset>
is the offset within
.I <block>
- given in hexadecimal

.I <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

.I <count>
is the number of objects to display - given in decimal

.TP
.BI dm[ap]
 displays aggregate disk (block) map

.BI SUBCOMMANDS
 m => modify map fields
 f => display free count
 t => display tree levels
 x => exit subcommand mode

.TP
.BI dt[ree] " <inode_number> [<file_set>]"
 displays root of the directory btree located at
.I <inode_number>
and enters a subcommand mode to navigate the btree

.I <inode_number>
is the directory's inode - given in decimal

.I <file_set>
currently must be zero

.BI 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

.TP
.BI fsckw[sphdr]
 displays the header of the fsck workspace in the aggregate

.BI SUBCOMMANDS:
 m => modify entries
 x => exit subcommand mode

.TP
.BI h[elp] " [<command>]"
 displays help for
.I <command>
 if no command is given, all possible commands are displayed

.TP
.BI ia[g] " [<IAG_number>] [a | s | <file_set>]"
 displays IAG information for
.I <IAG_number>
and enters subcommand mode

.I <IAG_number>
is given in decimal

.I a
is to use the primary aggregate inode table

.I s
is to use the secondary aggregate inode table

.I <file_set>
currently must be zero

.BI SUBCOMMANDS
 e => display/modify inode extents map
 m => modify IAG
 p => display/modify persistent map
 w => display/modify working map
 x => exit subcommand mode

.TP
.BI i[node] " [<inode_number>] [a | s | <file_set>]"
 displays inode information for
.I <inode_number>
and enters subcommand mode

.I <inode_number>
is given in decimal

.I a
is to use the primary aggregate inode table

.I s
is to use the secondary aggregate inode table

.I <file_set>
currently must be zero

.BI SUBCOMMANDS
 a => display/modify inode's ACL
 m => modify inode
 x => exit subcommand mode

.TP
.BI logs[uper]
 displays the journal log superblock and enters subcommand mode

.BI SUBCOMMANDS
 m => modify journal log superblock
 x => exit subcommand mode

.TP
.BI q[uit]
 exits jfs_debugfs

.TP
.BI se[t] " [<variable> <value>]"
.B * not implemented yet *
 set user-defined
.I <variable>
to
.I <value>
 if no arguments are given, displays all set variables

.I <variable>
must begin with an alphabetic character

.TP
.BI su[perblock] " [p | s]"
 displays superblock data

.I p
displays the primary superblock

.I s
displays the secondary superblock

.BI SUBCOMMANDS:
 m => modify entries
 x => exit subcommand mode

.TP
.BI s2p[erblock] " [p | s]"
 displays alternate superblock data

.I p
displays the primary superblock

.I s
displays the secondary superblock

.BI SUBCOMMANDS:
 m => modify entries
 x => exit subcommand mode

.TP
.BI u[nset] " <variable>"
.B * not implemented yet *
 deletes user-defined
.I <variable>

.TP
.BI xt[ree] " <inode_number> [<file_set>]"
 displays root of the non-directory btree located at
.I <inode_number>
and enters a subcommand mode to navigate the btree

.I <inode_number>
is the directory's inode - given in decimal

.I <file_set>
currently must be zero

.BI 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

.SH "REPORTING BUGS"
.PP
If you find a bug in
.B JFS
or
.BR jfs_debugfs ,
please report it via the bug tracking system ("Report Bugs" section) of the JFS project web site:
.nf
http://jfs.sourceforge.net/
.fi
.PP
Please send as much pertinent information as possible, including the complete output of running
.B jfs_fsck
with the
.B \-v
and
.B \-n
options on the JFS device.

.SH SEE ALSO
.BR jfs_fsck (8),
.BR jfs_mkfs (8),
.BR jfs_fscklog (8),
.BR jfs_logdump (8),
.BR jfs_tune (8),

.SH AUTHORS
.nf
Barry Arndt  (barndt@us.ibm.com)
William Braswell, Jr.

.fi
.B jfs_debugfs
is maintained by IBM.
.nf
See the JFS project web site for more details:
http://jfs.sourceforge.net/
.fi