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 E2FSCK 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
7 e2fsck \- check a Linux ext2/ext3/ext4 file system
31 @JDEV@.I external-journal
40 is used to check the ext2/ext3/ext4 family of file systems.
41 For ext3 and ext4 filesystems that use a journal, if the system has been
42 shut down uncleanly without any errors, normally, after replaying the
43 committed transactions in the journal, the file system should be
44 marked as clean. Hence, for filesystems that use journalling,
46 will normally replay the journal and exit, unless its superblock
47 indicates that further checking is required.
50 is the device file where the filesystem is stored (e.g.
53 Note that in general it is not safe to run
55 on mounted filesystems. The only exception is if the
57 option is specified, and
64 specified. However, even if it is safe to do so, the results printed by
66 are not valid if the filesystem is mounted. If
68 asks whether or not you should check a filesystem which is mounted,
69 the only correct answer is ``no''. Only experts who really know what
70 they are doing should consider answering this question in any other way.
74 is run in interactive mode (meaning that none of
79 are specified), the program will ask the user to fix each problem found in the
80 filesystem. A response of 'y' will fix the error; 'n' will leave the error
81 unfixed; and 'a' will fix the problem and all subsequent problems; pressing
82 Enter will proceed with the default response, which is printed before the
83 question mark. Pressing Control-C terminates e2fsck immediately.
87 This option does the same thing as the
89 option. It is provided for backwards compatibility only; it is
90 suggested that people use
92 option whenever possible.
95 Instead of using the normal superblock, use an alternative superblock
98 This option is normally used when the primary superblock has been
99 corrupted. The location of the backup superblock is dependent on the
100 filesystem's blocksize. For filesystems with 1k blocksizes, a backup
101 superblock can be found at block 8193; for filesystems with 2k
102 blocksizes, at block 16384; and for 4k blocksizes, at block 32768.
104 Additional backup superblocks can be determined by using the
108 option to print out where the superblocks were created. The
112 which specifies blocksize of the filesystem must be specified in order
113 for the superblock locations that are printed out to be accurate.
115 If an alternative superblock is specified and
116 the filesystem is not opened read-only, e2fsck will make sure that the
117 primary superblock is updated appropriately upon completion of the
123 will search for the superblock at various different
124 block sizes in an attempt to find the appropriate block size.
125 This search can be fooled in some cases. This option forces
127 to only try locating the superblock at a particular blocksize.
128 If the superblock is not found,
130 will terminate with a fatal error.
137 program to do a read-only scan of the device in order to find any bad
138 blocks. If any bad blocks are found, they are added to the bad block
139 inode to prevent them from being allocated to a file or directory. If
140 this option is specified twice, then the bad block scan will be done
141 using a non-destructive read-write test.
146 to write completion information to the specified file descriptor
147 so that the progress of the filesystem
148 check can be monitored. This option is typically used by programs
151 If the file descriptor number is negative, then absolute value of
152 the file descriptor will be used, and the progress information will be
153 suppressed initially. It can later be enabled by sending the
155 process a SIGUSR1 signal.
156 If the file descriptor specified is 0,
158 will print a completion bar as it goes about its business. This requires
159 that e2fsck is running on a video console or terminal.
162 Print debugging output (useless unless you are debugging
166 Optimize directories in filesystem. This option causes e2fsck to
167 try to optimize all directories, either by reindexing them if the
168 filesystem supports directory indexing, or by sorting and compressing
169 directories for smaller directories, or for filesystems using
170 traditional linear directories.
176 may sometimes optimize a few directories --- for example, if
177 directory indexing is enabled and a directory is not indexed and would
178 benefit from being indexed, or if the index structures are corrupted
179 and need to be rebuilt. The
181 option forces all directories in the filesystem to be optimized. This can
182 sometimes make them a little smaller and slightly faster to search, but
183 in practice, you should rarely need to use this option.
187 option will detect directory entries with duplicate names in a single
188 directory, which e2fsck normally does not enforce for performance reasons.
190 .BI \-E " extended_options"
191 Set e2fsck extended options. Extended options are comma
192 separated, and may take an argument using the equals ('=') sign. The
193 following options are supported:
196 .BI ea_ver= extended_attribute_version
197 Set the version of the extended attribute blocks which
199 will require while checking the filesystem. The version number may
200 be 1 or 2. The default extended attribute version format is 2.
203 Only replay the journal if required, but do not perform any further checks
207 During pass 1, print a detailed report of any discontiguous blocks for
208 files in the filesystem.
211 Attempt to discard free blocks and unused inode blocks after the full
212 filesystem check (discarding blocks is useful on solid state devices and sparse
213 / thin-provisioned storage). Note that discard is done in pass 5 AFTER the
214 filesystem has been fully checked and only if it does not contain recognizable
215 errors. However there might be cases where
217 does not fully recognize a problem and hence in this case this
218 option may prevent you from further manual data recovery.
221 Do not attempt to discard free blocks and unused inode blocks. This option is
222 exactly the opposite of discard option. This is set as default.
225 Use this many KiB of memory to pre-fetch metadata in the hopes of reducing
226 e2fsck runtime. By default, this is set to the size of two block groups' inode
227 tables (typically 4MiB on a regular ext4 filesystem); if this amount is more
228 than 1/50th of total physical memory, readahead is disabled. Set this to zero
229 to disable readahead entirely.
233 Force checking even if the file system seems clean.
236 Flush the filesystem device's buffer caches before beginning. Only
237 really useful for doing
241 @JDEV@.BI \-j " external-journal"
242 @JDEV@Set the pathname where the external-journal for this filesystem can be
246 When combined with the
248 option, any existing bad blocks in the bad blocks list are preserved,
249 and any new bad blocks found by running
251 will be added to the existing bad blocks list.
254 Add the block numbers listed in the file specified by
256 to the list of bad blocks. The format of this file is the same as the
259 program. Note that the block numbers are based on the blocksize
260 of the filesystem. Hence,
262 must be given the blocksize of the filesystem in order to obtain correct
263 results. As a result, it is much simpler and safer to use the
267 since it will assure that the correct parameters are passed to the
272 Set the bad blocks list to be the list of blocks specified by
274 (This option is the same as the
276 option, except the bad blocks list is cleared before the blocks listed
277 in the file are added to the bad blocks list.)
280 Open the filesystem read-only, and assume an answer of `no' to all
283 to be used non-interactively. This option
284 may not be specified at the same time as the
291 Automatically repair ("preen") the file system. This option will cause
294 fix any filesystem problems that can be safely fixed without human
297 discovers a problem which may require the system administrator
298 to take additional corrective action,
300 will print a description of the problem and then exit with the value 4
301 logically or'ed into the exit code. (See the \fBEXIT CODE\fR section.)
302 This option is normally used by the system's boot scripts. It may not
303 be specified at the same time as the
310 This option does nothing at all; it is provided only for backwards
314 Print timing statistics for
316 If this option is used twice, additional timing statistics are printed
317 on a pass by pass basis.
323 Print version information and exit.
326 Assume an answer of `yes' to all questions; allows
328 to be used non-interactively. This option
329 may not be specified at the same time as the
335 The exit code returned by
337 is the sum of the following conditions:
341 \ 1\ \-\ File system errors corrected
343 \ 2\ \-\ File system errors corrected, system should
347 \ 4\ \-\ File system errors left uncorrected
349 \ 8\ \-\ Operational error
351 \ 16\ \-\ Usage or syntax error
353 \ 32\ \-\ E2fsck canceled by user request
355 \ 128\ \-\ Shared library error
358 The following signals have the following effect when sent to
364 to start displaying a completion bar or emitting progress information.
365 (See discussion of the
372 to stop displaying a completion bar or emitting progress information.
374 Almost any piece of software will have bugs. If you manage to find a
375 filesystem which causes
379 is unable to repair, please report it to the author.
381 Please include as much information as possible in your bug report.
382 Ideally, include a complete transcript of the
384 run, so I can see exactly what error messages are displayed. (Make sure
385 the messages printed by
387 are in English; if your system has been
390 messages have been translated into another language, please set the the
392 environment variable to
394 so that the transcript of e2fsck's output will be useful to me.)
396 have a writable filesystem where the transcript can be stored, the
398 program is a handy way to save the output of
402 It is also useful to send the output of
404 If a specific inode or inodes seems to be giving
406 trouble, try running the
408 command and send the output of the
410 command run on the relevant inode(s). If the inode is a directory, the
413 command will allow you to extract the contents of the directory inode,
414 which can sent to me after being first run through
416 The most useful data you can send to help reproduce
417 the bug is a compressed raw image dump of the filesystem, generated using
421 man page for more details.
423 Always include the full version string which
425 displays when it is run, so I know which version you are running.
429 was written by Theodore Ts'o <tytso@mit.edu>.
git://git.whamcloud.com / tools / e2fsprogs.git / blob