2 .\" Copyright 1993, 1994, 1995 by Theodore Ts'o. All Rights Reserved.
3 .\" This file may be copied under the terms of the GNU Public License.
5 .TH DEBUGFS 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
7 debugfs \- ext2/ext3/ext4 file system debugger
39 program is an interactive file system debugger. It can be used to
40 examine and change the state of an ext2, ext3, or ext4 file system.
43 is the special file corresponding to the device containing the
44 file system (e.g /dev/hdXX).
48 Specifies that the file system should be opened in read-write mode.
49 Without this option, the file system is opened in read-only mode.
52 Specifies that the file system should be opened in catastrophic mode, in
53 which the inode and group bitmaps are not read initially. This can be
54 useful for filesystems with significant corruption, but because of this,
55 catastrophic mode forces the filesystem to be opened read-only.
60 represents an ext2 image file created by the
62 program. Since the ext2 image file only contains the superblock, block
63 group descriptor, block and inode allocation bitmaps, and
66 commands will not function properly.
68 no safety checks are in place, and
70 may fail in interesting ways if commands such as
72 etc. are tried without specifying the
78 is a debugging tool. It has rough edges!
80 .I -d data_source_device
83 option, specifies that
85 should be used when reading blocks not found in the ext2 image file.
86 This includes data, directory, and indirect blocks.
89 Forces the use of the given block size for the file system, rather than
90 detecting the correct block size as normal.
93 Causes the file system superblock to be read from the given block
94 number, instead of using the primary superblock (located at an offset of
95 1024 bytes from the beginning of the filesystem). If you specify the
97 option, you must also provide the blocksize of the filesystem via the
104 to read in commands from
106 and execute them. When
108 is finished executing those commands, it will exit.
113 to execute the single command
118 print the version number of
126 as an argument to specify an inode (as opposed to a pathname)
127 in the filesystem which is currently opened by
131 argument may be specified in two forms. The first form is an inode
132 number surrounded by angle brackets, e.g.,
134 The second form is a pathname; if the pathname is prefixed by a forward slash
135 ('/'), then it is interpreted relative to the root of the filesystem
136 which is currently opened by
138 If not, the pathname is
139 interpreted relative to the current working directory as maintained by
141 This may be modified by using the
149 This is a list of the commands which
153 .I bmap filespec logical_block
154 Print the physical block number corresponding to the logical block number
160 Dump the contents of the inode
165 Change the current working directory to
169 Change the root directory to be the directory
173 Close the currently open file system. If the
175 option is specified, write out any changes to the superblock and block
176 group descriptors to all of the backup superblocks, not just to the
180 Clear the contents of the inode
183 .I dump [-p] filespec out_file
184 Dump the contents of the inode
190 option is given set the owner, group and permissions information on
195 .I dump_extents [-n] [-l] filespec
196 Dump the the extent tree of the inode
202 to only display the interior nodes in the extent tree. The
206 to only display the leaf nodes in the extent tree.
208 (Please note that the length and range of blocks for the last extent in
209 an interior node is an estimate by the extents library functions, and is
210 not stored in file esystem data structures. Hence, the values displayed
211 may not necessarily by accurate and does not indicate a problem or
212 corruption in the file system.)
214 .I expand_dir filespec
218 .I feature [fs_feature] [-fs_feature] ...
219 Set or clear various filesystem features in the superblock. After setting
220 or clearing any filesystem features that were requested, print the current
221 state of the filesystem feature set.
223 .I find_free_block [count [goal]]
226 free blocks, starting from
230 .I find_free_inode [dir [mode]]
231 Find a free inode and allocate it. If present,
233 specifies the inode number of the directory
234 which the inode is to be located. The second
237 specifies the permissions of the new inode. (If the directory bit is set
238 on the mode, the allocation routine will function differently.)
240 .I freeb block [count]
241 Mark the block number
244 If the optional argument
248 blocks starting at block number
250 will be marked as not allocated.
253 Free the inode specified by
257 Print a list of commands understood by
261 Print a listing of the inodes which use the one or more blocks specified
265 Print the location of the inode data structure (in the inode table)
269 .I init_filesys device blocksize
270 Create an ext2 file system on
274 Note that this does not fully initialize all of the data structures;
277 program. This is just a call to the low-level library, which sets up
278 the superblock and block descriptors.
280 .I kill_file filespec
283 and its blocks. Note that this does not remove any directory
284 entries (if any) to this inode. See the
286 command if you wish to unlink a file.
289 Change the current working directory of the
293 on the native filesystem.
295 .I ln filespec dest_file
300 Note this does not adjust the inode reference counts.
302 .I logdump [-acs] [-b<block>] [-i<filespec>] [-f<journal_file>] [output_file]
303 Dump the contents of the ext3 journal. By default, the journal inode as
304 specified in the superblock. However, this can be overridden with the
306 option, which uses an inode specifier to specify the journal to be
307 used. A file containing journal data can be specified using the
311 option utilizes the backup information in the superblock to locate the
318 program to print the contents of all of the descriptor blocks.
323 to print all journal records that are refer to the specified block.
326 option will print out the contents of all of the data blocks selected by
333 .I ls [-l] [-d] [-p] filespec
334 Print a listing of the files in the directory
338 flag will list files using a more verbose format.
341 flag will list deleted entries in the directory.
344 flag will list the files in a format which is more easily parsable by
345 scripts, as well as making it more clear when there are spaces or other
346 non-printing characters at the end of filenames.
348 .I modify_inode filespec
349 Modify the contents of the inode structure in the inode
355 .I mknod filespec [p|[[c|b] major minor]]
356 Create a special device file (a named pipe, character or block device).
357 If a character or block device is to be made, the
361 device numbers must be specified.
363 .I ncheck inode_num ...
364 Take the requested list of inode numbers, and print a listing of pathnames
367 .I open [-w] [-e] [-f] [-i] [-c] [-b blocksize] [-s superblock] device
368 Open a filesystem for editing. The
370 flag forces the filesystem to be opened even if there are some unknown
371 or incompatible filesystem features which would normally
372 prevent the filesystem from being opened. The
374 flag causes the filesystem to be opened in exclusive mode. The
375 .IR -b ", " -c ", " -i ", " -s ", and " -w
376 options behave the same as the command-line options to
380 Print the current working directory.
386 .I rdump directory destination
389 and all its contents (including regular files, symbolic links, and other
390 directories) into the named
392 which should be an existing directory on the native filesystem.
397 If this causes the inode pointed to by
399 to have no other references, deallocate the file. This command functions
400 as the unlink() system call.
407 .I setb block [count]
408 Mark the block number
411 If the optional argument
415 blocks starting at block number
417 will be marked as allocated.
419 .I set_block_group bgnum field value
420 Modify the block group descriptor specified by
422 so that the block group descriptor field
430 as in use in the inode bitmap.
432 .I set_inode_field filespec field value
433 Modify the inode specified by
435 so that the inode field
439 The list of valid inode fields which can be set via this command
440 can be displayed by using the command:
441 .B set_inode_field -l
443 .I set_super_value field value
444 Set the superblock field
448 The list of valid superblock fields which can be set via this command
449 can be displayed by using the command:
450 .B set_super_value -l
452 .I show_super_stats [-h]
453 List the contents of the super block and the block group descriptors. If the
455 flag is given, only print out the superblock contents.
458 Display the contents of the inode structure of the inode
461 .I testb block [count]
462 Test if the block number
464 is marked as allocated in the block bitmap.
465 If the optional argument
469 blocks starting at block number
476 is marked as allocated in the inode bitmap.
478 .I undel <inode num> [pathname]
479 Undelete the specified inode number (which must be surrounded by angle
480 brackets) so that it and its blocks are marked in use, and optionally
481 link the recovered inode to the specified pathname. The
483 command should always be run after using the
485 command to recover deleted files.
487 Note that if you are recovering a large number of deleted files, linking
488 the inode to a directory may require the directory to be expanded, which
489 could allocate a block that had been used by one of the
490 yet-to-be-undeleted files. So it is safer to undelete all of the
491 inodes without specifying a destination pathname, and then in a separate
492 pass, use the debugfs
494 command to link the inode to the destination pathname, or use
496 to check the filesystem and link all of the recovered inodes to the
497 lost+found directory.
500 Remove the link specified by
502 to an inode. Note this does not adjust the inode reference counts.
504 .I write source_file out_file
505 Create a file in the filesystem named
507 and copy the contents of
509 into the destination file.
510 .SH ENVIRONMENT VARIABLES
512 .B DEBUGFS_PAGER, PAGER
515 program always pipes the output of the some commands through a
516 pager program. These commands include:
517 .IR show_super_stats ,
519 .IR show_inode_info ,
520 .IR list_deleted_inodes ,
523 The specific pager can explicitly specified by the
525 environment variable, and if it is not set, by the
527 environment variable.
529 Note that since a pager is always used, the
531 pager is not particularly appropriate, since it clears the screen before
532 displaying the output of the command and clears the output the screen
533 when the pager is exited. Many users prefer to use the
535 pager for most purposes, which is why the
537 environment variable is available to override the more general
539 environment variable.
542 was written by Theodore Ts'o <tytso@mit.edu>.