jfs_debugfs(8)						      JFS file system editor						    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 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)