1e2fsck.conf(5) File Formats Manual e2fsck.conf(5)
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6 e2fsck.conf - Configuration file for e2fsck
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9 e2fsck.conf is the configuration file for e2fsck(8). It controls the
10 default behavior of e2fsck(8) while it is checking ext2, ext3, or ext4
11 file systems.
12 The e2fsck.conf file uses an INI-style format. Stanzas, or top-level
14 sections, are delimited by square braces: [ ]. Within each section,
15 each line defines a relation, which assigns tags to values, or to a
16 subsection, which contains further relations or subsections. An exam‐
17 ple of the INI-style format used by this configuration file follows be‐
18 low:
19 [section1]
21 tag1 = value_a
22 tag1 = value_b
23 tag2 = value_c
24 [section 2]
26 tag3 = {
27 subtag1 = subtag_value_a
28 subtag1 = subtag_value_b
29 subtag2 = subtag_value_c
30 }
31 tag1 = value_d
32 tag2 = value_e
33 }
34 Comments are delimited by a semicolon (';') or a hash ('#') character
36 at the beginning of the comment, and are terminated by the end of line
37 character.
38 Tags and values must be quoted using double quotes if they contain spa‐
40 ces. Within a quoted string, the standard backslash interpretations
41 apply: "\n" (for the newline character), "\t" (for the tab character),
42 "\b" (for the backspace character), and "\\" (for the backslash charac‐
43 ter).
44 The following stanzas are used in the e2fsck.conf file. They will be
46 described in more detail in future sections of this document.
47 [options]
49 This stanza contains general configuration parameters for
50 e2fsck's behavior.
51 [defaults]
53 Contains relations which define the default parameters used by
54 e2fsck(8). In general, these defaults may be overridden by com‐
55 mand-line options provided by the user.
56 [problems]
58 This stanza allows the administrator to reconfigure how e2fsck
59 handles various file system inconsistencies.
60 [scratch_files]
62 This stanza controls when e2fsck will attempt to use scratch
63 files to reduce the need for memory.
64
66 The following relations are defined in the [options] stanza.
67 allow_cancellation
69 If this relation is set to a boolean value of true, then if the
70 user interrupts e2fsck using ^C, and the file system is not ex‐
71 plicitly flagged as containing errors, e2fsck will exit with an
72 exit status of 0 instead of 32. This setting defaults to false.
73 accept_time_fudge
75 Unfortunately, due to Windows' unfortunate design decision to
76 configure the hardware clock to tick localtime, instead of the
77 more proper and less error-prone UTC time, many users end up in
78 the situation where the system clock is incorrectly set at the
79 time when e2fsck is run.
80 Historically this was usually due to some distributions having
82 buggy init scripts and/or installers that didn't correctly de‐
83 tect this case and take appropriate countermeasures. Unfortu‐
84 nately, this is occasionally true even today, usually due to a
85 buggy or misconfigured virtualization manager or the installer
86 not having access to a network time server during the installa‐
87 tion process. So by default, we allow the superblock times to
88 be fudged by up to 24 hours. This can be disabled by setting
89 accept_time_fudge to the boolean value of false. This setting
90 defaults to true.
91 broken_system_clock
93 The e2fsck(8) program has some heuristics that assume that the
94 system clock is correct. In addition, many system programs make
95 similar assumptions. For example, the UUID library depends on
96 time not going backwards in order for it to be able to make its
97 guarantees about issuing universally unique ID's. Systems with
98 broken system clocks, are well, broken. However, broken system
99 clocks, particularly in embedded systems, do exist. E2fsck will
100 attempt to use heuristics to determine if the time can not be
101 trusted; and to skip time-based checks if this is true. If this
102 boolean is set to true, then e2fsck will always assume that the
103 system clock can not be trusted.
104 buggy_init_scripts
106 This boolean relation is an alias for accept_time_fudge for
107 backwards compatibility; it used to be that the behavior defined
108 by accept_time_fudge above defaulted to false, and
109 buggy_init_scripts would enable superblock time field to be
110 wrong by up to 24 hours. When we changed the default, we also
111 renamed this boolean relation to accept_time_fudge.
112 clear_test_fs_flag
114 This boolean relation controls whether or not e2fsck(8) will of‐
115 fer to clear the test_fs flag if the ext4 file system is avail‐
116 able on the system. It defaults to true.
117 defer_check_on_battery
119 This boolean relation controls whether or not the interval be‐
120 tween file system checks (either based on time or number of
121 mounts) should be doubled if the system is running on battery.
122 This setting defaults to true.
123 indexed_dir_slack_percentage
125 When e2fsck(8) repacks a indexed directory, reserve the speci‐
126 fied percentage of empty space in each leaf nodes so that a few
127 new entries can be added to the directory without splitting leaf
128 nodes, so that the average fill ratio of directories can be
129 maintained at a higher, more efficient level. This relation de‐
130 faults to 20 percent.
131 inode_count_fullmap
133 If this boolean relation is true, trade off using memory for
134 speed when checking a file system with a large number of hard-
135 linked files. The amount of memory required is proportional to
136 the number of inodes in the file system. For large file sys‐
137 tems, this can be gigabytes of memory. (For example a 40TB file
138 system with 2.8 billion inodes will consume an additional 5.7 GB
139 memory if this optimization is enabled.) This setting defaults
140 to false.
141 log_dir
143 If the log_filename or problem_log_filename relations contains a
144 relative pathname, then the log file will be placed in the di‐
145 rectory named by the log_dir relation.
146 log_dir_fallback
148 This relation contains an alternate directory that will be used
149 if the directory specified by log_dir is not available or is not
150 writable.
151 log_dir_wait
153 If this boolean relation is true, them if the directories speci‐
154 fied by log_dir or log_dir_fallback are not available or are not
155 yet writable, e2fsck will save the output in a memory buffer,
156 and a child process will periodically test to see if the log di‐
157 rectory has become available after the boot sequence has mounted
158 the requested file system for reading/writing. This implements
159 the functionality provided by logsave(8) for e2fsck log files.
160 log_filename
162 This relation specifies the file name where a copy of e2fsck's
163 output will be written. If certain problem reports are sup‐
164 pressed using the max_count_problems relation, (or on a per-
165 problem basis using the max_count relation), the full set of
166 problem reports will be written to the log file. The filename
167 may contain various percent-expressions (%D, %T, %N, etc.) which
168 will be expanded so that the file name for the log file can in‐
169 clude things like date, time, device name, and other run-time
170 parameters. See the LOGGING section for more details.
171 max_count_problems
173 This relation specifies the maximum number of problem reports of
174 a particular type will be printed to stdout before further prob‐
175 lem reports of that type are squelched. This can be useful if
176 the console is slow (i.e., connected to a serial port) and so a
177 large amount of output could end up delaying the boot process
178 for a long time (potentially hours).
179 no_optimize_extents
181 If this boolean relation is true, do not offer to optimize the
182 extent tree by reducing the tree's width or depth. This setting
183 defaults to false.
184 problem_log_filename
186 This relation specifies the file name where a log of problem
187 codes found by e2fsck be written. The filename may contain var‐
188 ious percent-expressions (%D, %T, %N, etc.) which will be ex‐
189 panded so that the file name for the log file can include things
190 like date, time, device name, and other run-time parameters.
191 See the LOGGING section for more details.
192 readahead_mem_pct
194 Use this percentage of memory to try to read in metadata blocks
195 ahead of the main e2fsck thread. This should reduce run times,
196 depending on the speed of the underlying storage and the amount
197 of free memory. There is no default, but see readahead_kb for
198 more details.
199 readahead_kb
201 Use this amount of memory to read in metadata blocks ahead of
202 the main checking thread. Setting this value to zero disables
203 readahead entirely. By default, this is set the size of two
204 block groups' inode tables (typically 4MiB on a regular ext4
205 file system); if this amount is more than 1/50th of total physi‐
206 cal memory, readahead is disabled.
207 report_features
209 If this boolean relation is true, e2fsck will print the file
210 system features as part of its verbose reporting (i.e., if the
211 -v option is specified)
212 report_time
214 If this boolean relation is true, e2fsck will run as if the op‐
215 tions -tt are always specified. This will cause e2fsck to print
216 timing statistics on a pass by pass basis for full file system
217 checks.
218 report_verbose
220 If this boolean relation is true, e2fsck will run as if the op‐
221 tion -v is always specified. This will cause e2fsck to print
222 some additional information at the end of each full file system
223 check.
224
226 The following relations are defined in the [defaults] stanza.
227 undo_dir
229 This relation specifies the directory where the undo file should
230 be stored. It can be overridden via the E2FSPROGS_UNDO_DIR en‐
231 vironment variable. If the directory location is set to the
232 value none, e2fsck will not create an undo file.
233
235 Each tag in the [problems] stanza names a problem code specified with a
236 leading "0x" followed by six hex digits. The value of the tag is a
237 subsection where the relations in that subsection override the default
238 treatment of that particular problem code.
239 Note that inappropriate settings in this stanza may cause e2fsck to be‐
241 have incorrectly, or even crash. Most system administrators should not
242 be making changes to this section without referring to source code.
243 Within each problem code's subsection, the following tags may be used:
245 description
247 This relation allows the message which is printed when this file
248 system inconsistency is detected to be overridden.
249 preen_ok
251 This boolean relation overrides the default behavior controlling
252 whether this file system problem should be automatically fixed
253 when e2fsck is running in preen mode.
254 max_count
256 This integer relation overrides the max_count_problems parameter
257 (set in the options section) for this particular problem.
258 no_ok This boolean relation overrides the default behavior determining
260 whether or not the file system will be marked as inconsistent if
261 the user declines to fix the reported problem.
262 no_default
264 This boolean relation overrides whether the default answer for
265 this problem (or question) should be "no".
266 preen_nomessage
268 This boolean relation overrides the default behavior controlling
269 whether or not the description for this file system problem
270 should be suppressed when e2fsck is running in preen mode.
271 no_nomsg
273 This boolean relation overrides the default behavior controlling
274 whether or not the description for this file system problem
275 should be suppressed when a problem forced not to be fixed, ei‐
276 ther because e2fsck is run with the -n option or because the
277 force_no flag has been set for the problem.
278 force_no
280 This boolean option, if set to true, forces a problem to never
281 be fixed. That is, it will be as if the user problem responds
282 'no' to the question of 'should this problem be fixed?'. The
283 force_no option even overrides the -y option given on the com‐
284 mand-line (just for the specific problem, of course).
285 not_a_fix
287 This boolean option, it set to true, marks the problem as one
288 where if the user gives permission to make the requested change,
289 it does not mean that the file system had a problem which has
290 since been fixed. This is used for requests to optimize the
291 file system's data structure, such as pruning an extent tree.
292
294 The following relations are defined in the [scratch_files] stanza.
295 directory
297 If the directory named by this relation exists and is writeable,
298 then e2fsck will attempt to use this directory to store scratch
299 files instead of using in-memory data structures.
300 numdirs_threshold
302 If this relation is set, then in-memory data structures will be
303 used if the number of directories in the file system are fewer
304 than amount specified.
305 dirinfo
307 This relation controls whether or not the scratch file directory
308 is used instead of an in-memory data structure for directory in‐
309 formation. It defaults to true.
310 icount This relation controls whether or not the scratch file directory
312 is used instead of an in-memory data structure when tracking in‐
313 ode counts. It defaults to true.
314
316 E2fsck has the facility to save the information from an e2fsck run in a
317 directory so that a system administrator can review its output at their
318 leisure. This allows information captured during the automatic e2fsck
319 preen run, as well as a manually started e2fsck run, to be saved for
320 posterity. This facility is controlled by the log_filename, log_dir,
321 log_dir_fallback, and log_dir_wait relations in the [options] stanza.
322 The filename in log_filename may contain the following percent-expres‐
324 sions that will be expanded as follows.
325 %d The current day of the month
327 %D The current date; this is a equivalent of %Y%m%d
329 %h The hostname of the system.
331 %H The current hour in 24-hour format (00..23)
333 %m The current month as a two-digit number (01..12)
335 %M The current minute (00..59)
337 %N The name of the block device containing the file system, with
339 any directory pathname stripped off.
340 %p The pid of the e2fsck process
342 %s The current time expressed as the number of seconds since
344 1970-01-01 00:00:00 UTC
345 %S The current second (00..59)
347 %T The current time; this is equivalent of %H%M%S
349 %u The name of the user running e2fsck.
351 %U This percent expression does not expand to anything, but it sig‐
353 nals that any following date or time expressions should be ex‐
354 pressed in UTC time instead of the local timezone.
355 %y The last two digits of the current year (00..99)
357 %Y The current year (i.e., 2012).
359
361 The following recipe will prevent e2fsck from aborting during the boot
362 process when a file system contains orphaned files. (Of course, this
363 is not always a good idea, since critical files that are needed for the
364 security of the system could potentially end up in lost+found, and
365 starting the system without first having a system administrator check
366 things out may be dangerous.)
367 [problems]
369 0x040002 = {
370 preen_ok = true
371 description = "@u @i %i. "
372 }
373 The following recipe will cause an e2fsck logfile to be written to the
375 directory /var/log/e2fsck, with a filename that contains the device
376 name, the hostname of the system, the date, and time: e.g., "e2fsck-
377 sda3.server.INFO.20120314-112142". If the directory containing
378 /var/log is located on the root file system which is initially mounted
379 read-only, then the output will be saved in memory and written out once
380 the root file system has been remounted read/write. To avoid too much
381 detail from being written to the serial console (which could poten‐
382 tially slow down the boot sequence), only print no more than 16 in‐
383 stances of each type of file system corruption.
384 [options]
386 max_count_problems = 16
387 log_dir = /var/log/e2fsck
388 log_filename = e2fsck-%N.%h.INFO.%D-%T
389 log_dir_wait = true
390
392 /etc/e2fsck.conf
393 The configuration file for e2fsck(8).
394
396 e2fsck(8)
397E2fsprogs version 1.46.5 December 2021 e2fsck.conf(5)