1jfs_debugfs(8) JFS file system editor jfs_debugfs(8)
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6 jfs_debugfs - shell-type JFS file system editor
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10 jfs_debugfs device
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14 jfs_debugfs is a program which can be used to perform various low-level
15 actions on a JFS formatted device.
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17 device is the special file name corresponding to the actual device to
18 be edited (e.g. /dev/hdb1).
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20 jfs_debugfs must be run as root.
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24 a[lter] <block> <offset> <hex_string>
25 replaces the data located at the <offset> of <block> with
26 <hex_string>
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28 <block> is the block number - given in decimal
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30 <offset> is the offset within that block - given in hexadecimal
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32 <hex_string> is an even-numbered string of hexadecimal digits to
33 write to the disk
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36 b[tree] <block> [<offset>]
37 * not implemented yet *
38 displays one node of the btree located at <offset> of <block>
39 and enters a subcommand mode to navigate the btree
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41 SUBCOMMANDS:
42 l => visit left sibling
43 m => modify current node
44 p => visit parent node
45 r => visit right sibling
46 [0-9] => visit the n'th child node
47 x => exit subcommand mode
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50 cb[blfsck]
51 displays the area used by ClearBadBlockList for communication
52 with fsck
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54 SUBCOMMANDS:
55 m => modify entries
56 x => exit subcommand mode
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59 dir[ectory] <inode_number> [<file_set>]
60 displays the directory entries at <inode_number> and enters
61 subcommand mode
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63 <inode_number> is the directory's inode - given in decimal
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65 <file_set> currently must be zero
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67 SUBCOMMANDS:
68 m => modify entries
69 x => exit subcommand mode
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72 d[isplay] [<block> [<offset> [<format> [<count>]]]]
73 displays <count> objects located at the <offset> of <block> in
74 <format>
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76 <block> is the block number - given in decimal
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78 <offset> is the offset within <block> - given in hexadecimal
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80 <format> is one of the following:
81 a => ascii
82 b => block allocation map
83 d => decimal
84 i => inode
85 I => inode allocation map
86 s => superblock
87 x => hexadecimal
88 X => extent allocation descriptor
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90 <count> is the number of objects to display - given in decimal
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93 dm[ap]
94 displays aggregate disk (block) map
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96 SUBCOMMANDS
97 m => modify map fields
98 f => display free count
99 t => display tree levels
100 x => exit subcommand mode
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103 dt[ree] <inode_number> [<file_set>]
104 displays root of the directory btree located at <inode_number>
105 and enters a subcommand mode to navigate the btree
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107 <inode_number> is the directory's inode - given in decimal
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109 <file_set> currently must be zero
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111 SUBCOMMANDS
112 l => visit left sibling
113 m => modify current node
114 p => visit parent node (not parent directory)
115 r => visit right sibling
116 [0-9] => visit the n'th child node
117 x => exit subcommand mode
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120 fsckw[sphdr]
121 displays the header of the fsck workspace in the aggregate
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123 SUBCOMMANDS:
124 m => modify entries
125 x => exit subcommand mode
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128 h[elp] [<command>]
129 displays help for <command>
130 if no command is given, all possible commands are displayed
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133 ia[g] [<IAG_number>] [a | s | <file_set>]
134 displays IAG information for <IAG_number> and enters subcommand
135 mode
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137 <IAG_number> is given in decimal
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139 a is to use the primary aggregate inode table
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141 s is to use the secondary aggregate inode table
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143 <file_set> currently must be zero
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145 SUBCOMMANDS
146 e => display/modify inode extents map
147 m => modify IAG
148 p => display/modify persistent map
149 w => display/modify working map
150 x => exit subcommand mode
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153 i[node] [<inode_number>] [a | s | <file_set>]
154 displays inode information for <inode_number> and enters sub‐
155 command mode
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157 <inode_number> is given in decimal
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159 a is to use the primary aggregate inode table
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161 s is to use the secondary aggregate inode table
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163 <file_set> currently must be zero
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165 SUBCOMMANDS
166 a => display/modify inode's ACL
167 m => modify inode
168 x => exit subcommand mode
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171 logs[uper]
172 displays the journal log superblock and enters subcommand mode
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174 SUBCOMMANDS
175 m => modify journal log superblock
176 x => exit subcommand mode
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179 q[uit]
180 exits jfs_debugfs
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183 se[t] [<variable> <value>]
184 * not implemented yet *
185 set user-defined <variable> to <value>
186 if no arguments are given, displays all set variables
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188 <variable> must begin with an alphabetic character
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191 su[perblock] [p | s]
192 displays superblock data
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194 p displays the primary superblock
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196 s displays the secondary superblock
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198 SUBCOMMANDS:
199 m => modify entries
200 x => exit subcommand mode
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203 s2p[erblock] [p | s]
204 displays alternate superblock data
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206 p displays the primary superblock
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208 s displays the secondary superblock
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210 SUBCOMMANDS:
211 m => modify entries
212 x => exit subcommand mode
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215 u[nset] <variable>
216 * not implemented yet *
217 deletes user-defined <variable>
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220 xt[ree] <inode_number> [<file_set>]
221 displays root of the non-directory btree located at <inode_num‐
222 ber> and enters a subcommand mode to navigate the btree
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224 <inode_number> is the directory's inode - given in decimal
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226 <file_set> currently must be zero
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228 SUBCOMMANDS
229 l => visit left sibling
230 m => modify current node
231 p => visit parent node (not parent directory)
232 r => visit right sibling
233 [0-9] => visit the n'th child node
234 x => exit subcommand mode
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238 If you find a bug in JFS or jfs_debugfs, please report it via the bug
239 tracking system ("Report Bugs" section) of the JFS project web site:
240 http://jfs.sourceforge.net/
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242 Please send as much pertinent information as possible, including the
243 complete output of running jfs_fsck with the -v and -n options on the
244 JFS device.
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248 jfs_fsck(8), jfs_mkfs(8), jfs_fscklog(8), jfs_logdump(8), jfs_tune(8),
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252 Barry Arndt (barndt@us.ibm.com)
253 William Braswell, Jr.
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255 jfs_debugfs is maintained by IBM.
256 See the JFS project web site for more details:
257 http://jfs.sourceforge.net/
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261 October 29, 2002 jfs_debugfs(8)