1E2FSCK(8) System Manager's Manual E2FSCK(8)
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6 e2fsck - check a Linux ext2/ext3/ext4 file system
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9 e2fsck [ -pacnyrdfkvtDFV ] [ -b superblock ] [ -B blocksize ] [ -l|-L
10 bad_blocks_file ] [ -C fd ] [ -j external-journal ] [ -E
11 extended_options ] device
12
14 e2fsck is used to check the ext2/ext3/ext4 family of file systems. For
15 ext3 and ext4 filesystems that use a journal, if the system has been
16 shut down uncleanly without any errors, normally, after replaying the
17 committed transactions in the journal, the file system should be
18 marked as clean. Hence, for filesystems that use journalling, e2fsck
19 will normally replay the journal and exit, unless its superblock indi‐
20 cates that further checking is required.
21 device is the device file where the filesystem is stored (e.g.
23 /dev/hdc1).
24 Note that in general it is not safe to run e2fsck on mounted filesys‐
26 tems. The only exception is if the -n option is specified, and -c, -l,
27 or -L options are not specified. However, even if it is safe to do
28 so, the results printed by e2fsck are not valid if the filesystem is
29 mounted. If e2fsck asks whether or not you should check a filesystem
30 which is mounted, the only correct answer is ``no''. Only experts who
31 really know what they are doing should consider answering this question
32 in any other way.
33
35 -a This option does the same thing as the -p option. It is pro‐
36 vided for backwards compatibility only; it is suggested that
37 people use -p option whenever possible.
38 -b superblock
40 Instead of using the normal superblock, use an alternative
41 superblock specified by superblock. This option is normally
42 used when the primary superblock has been corrupted. The loca‐
43 tion of the backup superblock is dependent on the filesystem's
44 blocksize. For filesystems with 1k blocksizes, a backup
45 superblock can be found at block 8193; for filesystems with 2k
46 blocksizes, at block 16384; and for 4k blocksizes, at block
47 32768.
48 Additional backup superblocks can be determined by using the
50 mke2fs program using the -n option to print out where the
51 superblocks were created. The -b option to mke2fs, which spec‐
52 ifies blocksize of the filesystem must be specified in order for
53 the superblock locations that are printed out to be accurate.
54 If an alternative superblock is specified and the filesystem is
56 not opened read-only, e2fsck will make sure that the primary
57 superblock is updated appropriately upon completion of the
58 filesystem check.
59 -B blocksize
61 Normally, e2fsck will search for the superblock at various dif‐
62 ferent block sizes in an attempt to find the appropriate block
63 size. This search can be fooled in some cases. This option
64 forces e2fsck to only try locating the superblock at a particu‐
65 lar blocksize. If the superblock is not found, e2fsck will ter‐
66 minate with a fatal error.
67 -c This option causes e2fsck to use badblocks(8) program to do a
69 read-only scan of the device in order to find any bad blocks.
70 If any bad blocks are found, they are added to the bad block
71 inode to prevent them from being allocated to a file or direc‐
72 tory. If this option is specified twice, then the bad block
73 scan will be done using a non-destructive read-write test.
74 -C fd This option causes e2fsck to write completion information to the
76 specified file descriptor so that the progress of the filesystem
77 check can be monitored. This option is typically used by pro‐
78 grams which are running e2fsck. If the file descriptor number
79 is negative, then absolute value of the file descriptor will be
80 used, and the progress information will be suppressed initially.
81 It can later be enabled by sending the e2fsck process a SIGUSR1
82 signal. If the file descriptor specified is 0, e2fsck will
83 print a completion bar as it goes about its business. This
84 requires that e2fsck is running on a video console or terminal.
85 -d Print debugging output (useless unless you are debugging
87 e2fsck).
88 -D Optimize directories in filesystem. This option causes e2fsck
90 to try to optimize all directories, either by reindexing them if
91 the filesystem supports directory indexing, or by sorting and
92 compressing directories for smaller directories, or for filesys‐
93 tems using traditional linear directories.
94 Even without the -D option, e2fsck may sometimes optimize a few
96 directories --- for example, if directory indexing is enabled
97 and a directory is not indexed and would benefit from being
98 indexed, or if the index structures are corrupted and need to be
99 rebuilt. The -D option forces all directories in the filesystem
100 to be optimized. This can sometimes make them a little smaller
101 and slightly faster to search, but in practice, you should
102 rarely need to use this option.
103 The -D option will detect directory entries with duplicate names
105 in a single directory, which e2fsck normally does not enforce
106 for performance reasons.
107 -E extended_options
109 Set e2fsck extended options. Extended options are comma sepa‐
110 rated, and may take an argument using the equals ('=') sign.
111 The following options are supported:
112 ea_ver=extended_attribute_version
114 Set the version of the extended attribute blocks
115 which e2fsck will require while checking the
116 filesystem. The version number may be 1 or 2. The
117 default extended attribute version format is 2.
118 journal_only
120 Only replay the journal if required, but do not per‐
121 form any further checks or repairs.
122 fragcheck
124 During pass 1, print a detailed report of any dis‐
125 contiguous blocks for files in the filesystem.
126 discard
128 Attempt to discard free blocks and unused inode
129 blocks after the full filesystem check (discarding
130 blocks is useful on solid state devices and sparse /
131 thin-provisioned storage). Note that discard is done
132 in pass 5 AFTER the filesystem has been fully
133 checked and only if it does not contain recognizable
134 errors. However there might be cases where e2fsck
135 does not fully recognize a problem and hence in this
136 case this option may prevent you from further manual
137 data recovery.
138 nodiscard
140 Do not attempt to discard free blocks and unused
141 inode blocks. This option is exactly the opposite of
142 discard option. This is set as default.
143 -f Force checking even if the file system seems clean.
145 -F Flush the filesystem device's buffer caches before beginning.
147 Only really useful for doing e2fsck time trials.
148 -j external-journal
150 Set the pathname where the external-journal for this filesystem
151 can be found.
152 -k When combined with the -c option, any existing bad blocks in the
154 bad blocks list are preserved, and any new bad blocks found by
155 running badblocks(8) will be added to the existing bad blocks
156 list.
157 -l filename
159 Add the block numbers listed in the file specified by filename
160 to the list of bad blocks. The format of this file is the same
161 as the one generated by the badblocks(8) program. Note that the
162 block numbers are based on the blocksize of the filesystem.
163 Hence, badblocks(8) must be given the blocksize of the filesys‐
164 tem in order to obtain correct results. As a result, it is much
165 simpler and safer to use the -c option to e2fsck, since it will
166 assure that the correct parameters are passed to the badblocks
167 program.
168 -L filename
170 Set the bad blocks list to be the list of blocks specified by
171 filename. (This option is the same as the -l option, except the
172 bad blocks list is cleared before the blocks listed in the file
173 are added to the bad blocks list.)
174 -n Open the filesystem read-only, and assume an answer of `no' to
176 all questions. Allows e2fsck to be used non-interactively.
177 This option may not be specified at the same time as the -p or
178 -y options.
179 -p Automatically repair ("preen") the file system. This option
181 will cause e2fsck to automatically fix any filesystem problems
182 that can be safely fixed without human intervention. If e2fsck
183 discovers a problem which may require the system administrator
184 to take additional corrective action, e2fsck will print a
185 description of the problem and then exit with the value 4 logi‐
186 cally or'ed into the exit code. (See the EXIT CODE section.)
187 This option is normally used by the system's boot scripts. It
188 may not be specified at the same time as the -n or -y options.
189 -r This option does nothing at all; it is provided only for back‐
191 wards compatibility.
192 -t Print timing statistics for e2fsck. If this option is used
194 twice, additional timing statistics are printed on a pass by
195 pass basis.
196 -v Verbose mode.
198 -V Print version information and exit.
200 -y Assume an answer of `yes' to all questions; allows e2fsck to be
202 used non-interactively. This option may not be specified at the
203 same time as the -n or -p options.
204
206 The exit code returned by e2fsck is the sum of the following condi‐
207 tions:
208 0 - No errors
209 1 - File system errors corrected
210 2 - File system errors corrected, system should
211 be rebooted
212 4 - File system errors left uncorrected
213 8 - Operational error
214 16 - Usage or syntax error
215 32 - E2fsck canceled by user request
216 128 - Shared library error
217
219 The following signals have the following effect when sent to e2fsck.
220 SIGUSR1
222 This signal causes e2fsck to start displaying a completion bar
223 or emitting progress information. (See discussion of the -C
224 option.)
225 SIGUSR2
227 This signal causes e2fsck to stop displaying a completion bar or
228 emitting progress information.
229
231 Almost any piece of software will have bugs. If you manage to find a
232 filesystem which causes e2fsck to crash, or which e2fsck is unable to
233 repair, please report it to the author.
234 Please include as much information as possible in your bug report.
236 Ideally, include a complete transcript of the e2fsck run, so I can see
237 exactly what error messages are displayed. (Make sure the messages
238 printed by e2fsck are in English; if your system has been configured so
239 that e2fsck's messages have been translated into another language,
240 please set the the LC_ALL environment variable to C so that the tran‐
241 script of e2fsck's output will be useful to me.) If you have a
242 writable filesystem where the transcript can be stored, the script(1)
243 program is a handy way to save the output of e2fsck to a file.
244 It is also useful to send the output of dumpe2fs(8). If a specific
246 inode or inodes seems to be giving e2fsck trouble, try running the
247 debugfs(8) command and send the output of the stat(1u) command run on
248 the relevant inode(s). If the inode is a directory, the debugfs dump
249 command will allow you to extract the contents of the directory inode,
250 which can sent to me after being first run through uuencode(1). The
251 most useful data you can send to help reproduce the bug is a compressed
252 raw image dump of the filesystem, generated using e2image(8). See the
253 e2image(8) man page for more details.
254 Always include the full version string which e2fsck displays when it is
256 run, so I know which version you are running.
257
259 This version of e2fsck was written by Theodore Ts'o <tytso@mit.edu>.
260
262 e2fsck.conf(5), badblocks(8), dumpe2fs(8), debugfs(8), e2image(8),
263 mke2fs(8), tune2fs(8)
264E2fsprogs version 1.42.9 December 2013 E2FSCK(8)