[Cluster-devel] cluster/gfs2/man gfs2_edit.8

Tue Sep 18 20:24:50 UTC 2007

CVSROOT:	/cvs/cluster
Module name:	cluster
Branch: 	RHEL5
Changes by:	rpeterso at sourceware.org	2007-09-18 20:24:50

Added files:
	gfs2/man       : gfs2_edit.8 

Log message:
	Resolves: bz 247318: Need man page for gfs2_edit

Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/cluster/gfs2/man/gfs2_edit.8.diff?cvsroot=cluster&only_with_tag=RHEL5&r1=NONE&r2=1.1.2.1

/cvs/cluster/cluster/gfs2/man/gfs2_edit.8,v  -->  standard output
revision 1.1.2.1

--- cluster/gfs2/man/gfs2_edit.8
+++ -	2007-09-18 20:24:50.229442000 +0000
@@ -0,0 +1,274 @@
+.\"  Copyright (C) 2007 Red Hat, Inc.  All rights reserved.
+
+.TH gfs2_edit 8
+
+.SH NAME
+gfs2_edit - Display, print or edit GFS2 internal structures.
+
+.SH SYNOPSIS
+.B gfs2_edit
+[\fIOPTION\fR]... [\fIDEVICE\fR]
+
+.SH DESCRIPTION
+The gfs2_edit command is a tool used to examine, edit or
+display internal data structures of a GFS2 or GFS file system.
+The gfs2_edit command can be run interactively, as described
+below in INTERACTIVE MODE.
+
+Caution: Several options of the gfs2_edit command alter the
+file system metadata and can cause file system corruption.
+These options should be used with great care.
+
+.SH OPTIONS
+.TP
+\fB-p\fP [\fIstructure\fR | \fIblock\fR]
+Print a gfs2 data structure in human-readable format to stdout.
+You can enter either a block number or a data structure name.  Block numbers
+may be specified in hex (e.g., 0x10) or decimal (e.g., 16).
+
+You can specify the following data structure names with the -p option.
+
+\fIsb\fR, \fIsuperblock\fR - Print the superblock.
+
+\fIroot\fR - Print the root directory.
+
+\fImaster\fR - Print the master system directory.
+
+\fIjindex\fR - Print the journal index system directory.
+
+\fIper_node\fR - Print the per_node system directory.
+
+\fIinum\fR - Print the system inum file.
+
+\fIstatfs\fR - Print the system statfs file.
+
+\fIrindex\fR, \fIrgindex\fR - Print the resource group index system file.
+
+\fIrgs\fR - Print the resource group information.
+
+\fIquota\fR - Print the contents of the system quota file.
+
+\fIidentify\fR - Identify a data block rather than print the block's contents.
+
+\fIsize\fR - Print the device size information.
+
+\fIjournalX\fR - Print the contents of journal X, where X is a journal
+number from 0 to <the number of journals in your file system - 1>.
+Only the journal headers and journal descriptors are dumped.  For journal
+descriptors, this option prints out every file system block number logged
+in that section of the journal.  The actual journaled blocks are not printed.
+
+If you specify a block number rather than a structure name, gfs2_edit will
+print out a breakdown of the structure for that block.
+For example: \fBgfs2_edit -p sb\fP will print the superblock, but so does
+\fBgfs2_edit -p 0x10\fP and \fBgfs2_edit -p 16\fP.
+
+If you specify -p without a block or structure name, gfs2_edit prints the
+superblock.
+
+You can specify more than one data structure with a single -p option.
+For example, "gfs2_edit -p inum statfs /dev/sda1" prints the system inum
+file and the system statfs file on /dev/sda1.
+
+.TP
+\fB-h, -help, -usage\fP
+Print help information.
+.TP
+\fB-c\fP [\fI0\fR | \fI1\fR]
+Use alternate color scheme for interactive mode: 0=normal (dark colors on
+white background), or 1 (light colors on black background).
+.TP
+\fB-V\fP
+Print program version information only.
+.TP
+\fB-x\fP
+Print in hex mode.
+
+.TP
+\fBsavemeta\fP \fI<device>\fR \fI<filename>\fR
+Save off the GFS2 metadata (not user data) for the file system on the
+specified device to a file given by <filename>.  You can use this option
+to analyze file system problems without revealing sensitive information
+that may be contained in the files.  This option works quickly by
+using the system bitmap blocks in the resource groups to determine the
+location of all the metadata.  If there is corruption
+in the bitmaps, resource groups or rindex file, this method may fail and
+you may need to use the savemetaslow option.
+The destination file is not compressed.  You may want to compress it
+with a program such as bzip2 before sending it for analysis.
+.TP
+\fBsavemetaslow\fP \fI<device>\fR \fI<filename>\fR
+Save off GFS2 metadata, as with the savemeta option, examining every
+block in the file system for metadata.  This option is less prone to failure
+due to file system corruption than the savemeta option, but it is 
+extremely slow.
+.TP
+\fBrestoremeta\fP \fI<filename>\fR \fI<dest device>\fR
+Take a file created with the savemeta option and restores its
+contents on top of the specified destination device.  \fBWARNING\fP:
+When you use this option, the file system and all data on the 
+destination device is destroyed.  Since only metadata (but no data) 
+is restored, every file in the resulting file system is likely to be
+corrupt.  The ONLY purpose of this option is to examine and debug file
+system problems by restoring and examining the state of the saved metadata.
+If the destination file system is the same size or larger than the source
+file system where the metadata was saved, the resulting file system
+will be the same size as the source.  If the destination device is
+smaller than the source file system, gfs2_edit will restore as much as
+it can, then quit, leaving you with a file system that probably will not
+mount, but from which you might still be able to figure out what is
+wrong with the source file system.
+
+.SH INTERACTIVE MODE
+If you specify a device on the gfs2_edit command line and you specify
+no options other than -c, gfs2_edit will act as an interactive GFS2
+file system editor for the file system you specify.  There
+are three display modes: hex mode, structure mode and pointers mode.
+You use the m key to switch between the modes, as described below.
+The modes are as follows:
+.TP
+Hex mode (default)
+Display or edits blocks of the file system in hexadecimal and ascii.
+
+Lines at the top indicate the currently displayed block in both hex and
+decimal.  If the block contains a GFS2 data structure, the name of that
+structure will appear in the upper right corner of the display.
+If the block is a well-known block, such as the superblock or rindex,
+there will be a line to indicate what it is.
+
+In hex mode, you can edit blocks by pressing \fB<enter>\fP and entering
+hexadecimal digits to replace the highlighted hex digits.  Do NOT precede
+the numbers with "0x".  For example, if you want to change the value at
+offset 0x60 from a 0x12 to 0xef, position your cursor to offset 0x60,
+so that the 12 is highlighted, then press \fB<enter>\fP and type in "ef".
+Press \fB<escape>\fP or \fB<enter>\fP to exit edit mode.
+
+In hex mode, different colors indicate different things.
+For example, in the default color scheme, the GFS2 data structure will
+be black, data offsets will be light blue, and actual data (anything after
+the gfs2 data structure) will be red.
+
+.TP
+Structure mode
+Decode the file system block into its GFS2 structure and
+display the values of that structure.  This mode is most useful for
+jumping around the file system.  For example, you can use the arrow 
+keys to position down to a pointer and press \fBJ\fP to jump to that block.
+
+.TP
+Pointers mode
+Display any additional information appearing on the block.
+For example, if an inode has block pointers, this will display them and
+allow you to scroll through them.  You can also position to one of them
+and press \fBJ\fP to jump to that block.
+
+.SH Interactive mode command keys:
+.TP
+\fBq\fP or \fB<esc>\fP
+The \fBq\fP or \fB<escape>\fP keys are used to exit gfs2_edit.
+
+.TP
+\fB<arrow/movement keys>\fP up, down, right, left, pg-up, pg-down, home, end
+The arrow keys are used to highlight an area of the display.  The \fBJ\fP
+key may be used to jump to the block that is highlighted.
+
+.TP
+\fBm\fP - Mode switch
+The \fBm\fP key is used to switch between the three display modes.
+The initial mode is hex mode.  Pressing the \fBm\fP key once switches to
+structure mode.  Pressing it a second time switches from structure mode
+to pointers mode.  Pressing it a third time takes you back to hex mode again.
+
+.TP
+\fBj\fP - Jump to block
+The \fBj\fP key jumps to the block number that is currently highlighted.
+In hex mode, hitting J will work when any byte of the pointer is highlighted.
+
+.TP
+\fBg\fP - Goto block
+The \fBg\fP key asks for a block number, then jumps there.  Note that
+in many cases, you can also arrow up so that the current block number
+is highlighted, then press \fB<enter>\fP to enter a block number to jump to.
+
+.TP
+\fBh\fP - Help display
+The \fBh\fP key causes the interactive help display to be shown.
+
+.TP
+\fBe\fP - Extended mode
+The \fBe\fP key causes gfs2_edit to switch to extended ("pointers") mode.
+
+.TP
+\fBc\fP - Color scheme
+The \fBc\fP key causes gfs2_edit to switch to its alternate color scheme.
+
+.TP
+\fBf\fP - Forward block
+The \fBf\fP key causes you to scroll forward one block.  This does
+not affect the "jump" status.  In other words, if you use the \fBf\fP
+key to move forward several blocks, pressing \fB<backspace>\fP will
+not roll you back up.
+
+.TP
+\fB<enter>\fP - Edit value
+The \fB<enter>\fP key causes you to go from display mode to edit mode.
+If you are in hex mode and you hit enter, you can type new hex values
+at the cursor's current location.  Note: Currently hitting \fB<enter>\fP
+in structure mode allows you to enter a new value, but it will not actually
+change the value on disk.  That is a future feature.
+
+.TP
+\fB<home>\fP
+If you are in pointers mode, this takes you back to the starts of the
+pointers you are viewing.  Otherwise it takes you back to the superblock.
+
+.TP
+\fB<backspace>\fP
+This takes you back to the block you were displaying before a jump.
+
+.TP
+\fB<space>\fP
+This takes you forward to the block you were displaying when you hit
+\fB<backspace>\fP.
+
+.SH EXAMPLES
+.TP
+gfs2_edit /dev/roth_vg/roth_lv
+Display and optionally edit the file system on /dev/roth_vg/roth_lv
+
+.TP
+gfs2_edit -p sb /dev/vg0/lvol0
+Print the superblock of the gfs2 file system located on
+/dev/vg0/lvol0.
+
+.TP
+gfs2_edit -p identify 2746 2748 /dev/sda2
+Print out what kind of blocks are at block numbers 2746 and 2748 on
+device /dev/sda2.
+
+.TP
+gfs2_edit -p rindex /dev/sda1
+Print the resource group index system file located on device
+/dev/sda1.
+
+.TP
+gfs2_edit savemeta /dev/sda1 /tmp/our_fs
+Save off all metadata (but no user data) to file /tmp/our_fs.
+
+.TP
+gfs2_edit -p root /dev/my_vg/my_lv
+Print the contents of the root directory in /dev/my_vg/my_lv.
+
+.TP
+gfs2-edit -x -p 0x3f7a /dev/sda1
+Print the contents of block 16250 of /dev/sda1 in hex.
+
+.TP
+gfs2_edit -p 12345 /dev/sdc2
+Print the gfs2 data structure at block 12345.
+
+.SH KNOWN BUGS
+.TP
+The directory code does not work well.  It might be confused
+by directory "sentinel" entries.
+


