Provided by: e2fsprogs_1.45.5-2ubuntu1.2_amd64 
NAME
e2fsck.conf - Configuration file for e2fsck
DESCRIPTION
e2fsck.conf is the configuration file for e2fsck(8). It controls the default behavior of e2fsck(8) while
it is checking ext2, ext3, or ext4 filesystems.
The e2fsck.conf file uses an INI-style format. Stanzas, or top-level sections, are delimited by square
braces: [ ]. Within each section, each line defines a relation, which assigns tags to values, or to a
subsection, which contains further relations or subsections. An example of the INI-style format used by
this configuration file follows below:
[section1]
tag1 = value_a
tag1 = value_b
tag2 = value_c
[section 2]
tag3 = {
subtag1 = subtag_value_a
subtag1 = subtag_value_b
subtag2 = subtag_value_c
}
tag1 = value_d
tag2 = value_e
}
Comments are delimited by a semicolon (';') or a hash ('#') character at the beginning of the comment,
and are terminated by the end of line character.
Tags and values must be quoted using double quotes if they contain spaces. Within a quoted string, the
standard backslash interpretations apply: "\n" (for the newline character), "\t" (for the tab character),
"\b" (for the backspace character), and "\\" (for the backslash character).
The following stanzas are used in the e2fsck.conf file. They will be described in more detail in future
sections of this document.
[options]
This stanza contains general configuration parameters for e2fsck's behavior.
[defaults]
Contains relations which define the default parameters used by e2fsck(8). In general, these
defaults may be overridden by command-line options provided by the user.
[problems]
This stanza allows the administrator to reconfigure how e2fsck handles various filesystem
inconsistencies.
[scratch_files]
This stanza controls when e2fsck will attempt to use scratch files to reduce the need for memory.
THE [options] STANZA
The following relations are defined in the [options] stanza.
allow_cancellation
If this relation is set to a boolean value of true, then if the user interrupts e2fsck using ^C,
and the filesystem is not explicitly flagged as containing errors, e2fsck will exit with an exit
status of 0 instead of 32. This setting defaults to false.
accept_time_fudge
Unfortunately, due to Windows' unfortunate design decision to configure the hardware clock to tick
localtime, instead of the more proper and less error-prone UTC time, many users end up in the
situation where the system clock is incorrectly set at the time when e2fsck is run.
Historically this was usually due to some distributions having buggy init scripts and/or
installers that didn't correctly detect this case and take appropriate countermeasures.
Unfortunately, this is occasionally true even today, usually due to a buggy or misconfigured
virtualization manager or the installer not having access to a network time server during the
installation process. So by default, we allow the superblock times to be fudged by up to 24
hours. This can be disabled by setting accept_time_fudge to the boolean value of false. This
setting defaults to true.
broken_system_clock
The e2fsck(8) program has some heuristics that assume that the system clock is correct. In
addition, many system programs make similar assumptions. For example, the UUID library depends on
time not going backwards in order for it to be able to make its guarantees about issuing
universally unique ID's. Systems with broken system clocks, are well, broken. However, broken
system clocks, particularly in embedded systems, do exist. E2fsck will attempt to use heuristics
to determine if the time can not be trusted; and to skip time-based checks if this is true. If
this boolean is set to true, then e2fsck will always assume that the system clock can not be
trusted.
buggy_init_scripts
This boolean relation is an alias for accept_time_fudge for backwards compatibility; it used to be
that the behavior defined by accept_time_fudge above defaulted to false, and buggy_init_scripts
would enable superblock time field to be wrong by up to 24 hours. When we changed the default, we
also renamed this boolean relation to accept_time_fudge.
clear_test_fs_flag
This boolean relation controls whether or not e2fsck(8) will offer to clear the test_fs flag if
the ext4 filesystem is available on the system. It defaults to true.
defer_check_on_battery
This boolean relation controls whether or not the interval between filesystem checks (either based
on time or number of mounts) should be doubled if the system is running on battery. This setting
defaults to true.
indexed_dir_slack_percentage
When e2fsck(8) repacks a indexed directory, reserve the specified percentage of empty space in
each leaf nodes so that a few new entries can be added to the directory without splitting leaf
nodes, so that the average fill ratio of directories can be maintained at a higher, more efficient
level. This relation defaults to 20 percent.
inode_count_fullmap
If this boolean relation is true, trade off using memory for speed when checking a file system
with a large number of hard-linked files. The amount of memory required is proportional to the
number of inodes in the file system. For large file systems, this can be gigabytes of memory.
(For example a 40TB file system with 2.8 billion inodes will consume an additional 5.7 GB memory
if this optimization is enabled.) This setting defaults to false.
log_dir
If the log_filename or problem_log_filename relations contains a relative pathname, then the log
file will be placed in the directory named by the log_dir relation.
log_dir_fallback
This relation contains an alternate directory that will be used if the directory specified by
log_dir is not available or is not writable.
log_dir_wait
If this boolean relation is true, them if the directories specified by log_dir or log_dir_fallback
are not available or are not yet writable, e2fsck will save the output in a memory buffer, and a
child process will periodically test to see if the log directory has become available after the
boot sequence has mounted the requested file system for reading/writing. This implements the
functionality provided by logsave(8) for e2fsck log files.
log_filename
This relation specifies the file name where a copy of e2fsck's output will be written. If
certain problem reports are suppressed using the max_count_problems relation, (or on a per-problem
basis using the max_count relation), the full set of problem reports will be written to the log
file. The filename may contain various percent-expressions (%D, %T, %N, etc.) which will be
expanded so that the file name for the log file can include things like date, time, device name,
and other run-time parameters. See the LOGGING section for more details.
max_count_problems
This relation specifies the maximum number of problem reports of a particular type will be printed
to stdout before further problem reports of that type are squelched. This can be useful if the
console is slow (i.e., connected to a serial port) and so a large amount of output could end up
delaying the boot process for a long time (potentially hours).
no_optimize_extents
If this boolean relation is true, do not offer to optimize the extent tree by reducing the tree's
width or depth. This setting defaults to false.
problem_log_filename
This relation specifies the file name where a log of problem codes found by e2fsck be written.
The filename may contain various percent-expressions (%D, %T, %N, etc.) which will be expanded so
that the file name for the log file can include things like date, time, device name, and other
run-time parameters. See the LOGGING section for more details.
readahead_mem_pct
Use this percentage of memory to try to read in metadata blocks ahead of the main e2fsck thread.
This should reduce run times, depending on the speed of the underlying storage and the amount of
free memory. There is no default, but see readahead_kb for more details.
readahead_kb
Use this amount of memory to read in metadata blocks ahead of the main checking thread. Setting
this value to zero disables readahead entirely. By default, this is set the size of two block
groups' inode tables (typically 4MiB on a regular ext4 filesystem); if this amount is more than
1/50th of total physical memory, readahead is disabled.
report_features
If this boolean relation is true, e2fsck will print the file system features as part of its
verbose reporting (i.e., if the -v option is specified)
report_time
If this boolean relation is true, e2fsck will run as if the options -tt are always specified.
This will cause e2fsck to print timing statistics on a pass by pass basis for full file system
checks.
report_verbose
If this boolean relation is true, e2fsck will run as if the option -v is always specified. This
will cause e2fsck to print some additional information at the end of each full file system check.
THE [defaults] STANZA
The following relations are defined in the [defaults] stanza.
undo_dir
This relation specifies the directory where the undo file should be stored. It can be overridden
via the E2FSPROGS_UNDO_DIR environment variable. If the directory location is set to the value
none, e2fsck will not create an undo file.
THE [problems] STANZA
Each tag in the [problems] stanza names a problem code specified with a leading "0x" followed by six hex
digits. The value of the tag is a subsection where the relations in that subsection override the default
treatment of that particular problem code.
Note that inappropriate settings in this stanza may cause e2fsck to behave incorrectly, or even crash.
Most system administrators should not be making changes to this section without referring to source code.
Within each problem code's subsection, the following tags may be used:
description
This relation allows the message which is printed when this filesystem inconsistency is detected
to be overridden.
preen_ok
This boolean relation overrides the default behavior controlling whether this filesystem problem
should be automatically fixed when e2fsck is running in preen mode.
max_count
This integer relation overrides the max_count_problems parameter (set in the options section) for
this particular problem.
no_ok This boolean relation overrides the default behavior determining whether or not the filesystem
will be marked as inconsistent if the user declines to fix the reported problem.
no_default
This boolean relation overrides whether the default answer for this problem (or question) should
be "no".
preen_nomessage
This boolean relation overrides the default behavior controlling whether or not the description
for this filesystem problem should be suppressed when e2fsck is running in preen mode.
no_nomsg
This boolean relation overrides the default behavior controlling whether or not the description
for this filesystem problem should be suppressed when a problem forced not to be fixed, either
because e2fsck is run with the -n option or because the force_no flag has been set for the
problem.
force_no
This boolean option, if set to true, forces a problem to never be fixed. That is, it will be as
if the user problem responds 'no' to the question of 'should this problem be fixed?'. The
force_no option even overrides the -y option given on the command-line (just for the specific
problem, of course).
not_a_fix
This boolean option, it set to true, marks the problem as one where if the user gives permission
to make the requested change, it does not mean that the file system had a problem which has since
been fixed. This is used for requests to optimize the file system's data structure, such as
pruning an extent tree.
THE [scratch_files] STANZA
The following relations are defined in the [scratch_files] stanza.
directory
If the directory named by this relation exists and is writeable, then e2fsck will attempt to use
this directory to store scratch files instead of using in-memory data structures.
numdirs_threshold
If this relation is set, then in-memory data structures will be used if the number of directories
in the filesystem are fewer than amount specified.
dirinfo
This relation controls whether or not the scratch file directory is used instead of an in-memory
data structure for directory information. It defaults to true.
icount This relation controls whether or not the scratch file directory is used instead of an in-memory
data structure when tracking inode counts. It defaults to true.
LOGGING
E2fsck has the facility to save the information from an e2fsck run in a directory so that a system
administrator can review its output at their leisure. This allows information captured during the
automatic e2fsck preen run, as well as a manually started e2fsck run, to be saved for posterity. This
facility is controlled by the log_filename, log_dir, log_dir_fallback, and log_dir_wait relations in the
[options] stanza.
The filename in log_filename may contain the following percent-expressions that will be expanded as
follows.
%d The current day of the month
%D The current date; this is a equivalent of %Y%m%d
%h The hostname of the system.
%H The current hour in 24-hour format (00..23)
%m The current month as a two-digit number (01..12)
%M The current minute (00..59)
%N The name of the block device containing the file system, with any directory pathname stripped off.
%p The pid of the e2fsck process
%s The current time expressed as the number of seconds since 1970-01-01 00:00:00 UTC
%S The current second (00..59)
%T The current time; this is equivalent of %H%M%S
%u The name of the user running e2fsck.
%U This percent expression does not expand to anything, but it signals that any following date or
time expressions should be expressed in UTC time instead of the local timezone.
%y The last two digits of the current year (00..99)
%Y The current year (i.e., 2012).
EXAMPLES
The following recipe will prevent e2fsck from aborting during the boot process when a filesystem contains
orphaned files. (Of course, this is not always a good idea, since critical files that are needed for the
security of the system could potentially end up in lost+found, and starting the system without first
having a system administrator check things out may be dangerous.)
[problems]
0x040002 = {
preen_ok = true
description = "@u @i %i. "
}
The following recipe will cause an e2fsck logfile to be written to the directory /var/log/e2fsck, with a
filename that contains the device name, the hostname of the system, the date, and time: e.g., "e2fsck-
sda3.server.INFO.20120314-112142". If the directory containing /var/log is located on the root file
system which is initially mounted read-only, then the output will be saved in memory and written out once
the root file system has been remounted read/write. To avoid too much detail from being written to the
serial console (which could potentially slow down the boot sequence), only print no more than 16
instances of each type of file system corruption.
[options]
max_count_problems = 16
log_dir = /var/log/e2fsck
log_filename = e2fsck-%N.%h.INFO.%D-%T
log_dir_wait = true
FILES
/etc/e2fsck.conf
The configuration file for e2fsck(8).
SEE ALSO
e2fsck(8)