e2fsck.conf(5) - phpMan

e2fsck.conf(5) File Formats Manual e2fsck.conf(5)

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 file systems.

The e2fsck.conf file uses an INI-style format. Stanzas, or top-level sections, are delim-
ited by square braces: [ ]. Within each section, each line defines a relation, which as-
signs 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 charac-
ter), "\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 gen-
eral, 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 file
system 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 file system is not explicitly flagged as containing er-
rors, e2fsck will exit with an exit status of 0 instead of 32. This setting de-
faults to false.

accept_time_fudge
Unfortunately, due to Windows' unfortunate design decision to configure the hard-
ware 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 coun-
termeasures. 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 cor-
rect. 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 compatibil-
ity; 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 file system is available on the system. It defaults to
true.

defer_check_on_battery
This boolean relation controls whether or not the interval between file system
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 direc-
tory 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 re-
quired 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 en-
abled.) 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 re-
quested file system for reading/writing. This implements the functionality pro-
vided by logsave(8) for e2fsck log files.

log_filename
This relation specifies the file name where a copy of e2fsck's output will be writ-
ten. If certain problem reports are suppressed using the max_count_problems rela-
tion, (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 re-
ducing 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 LOG-
GING 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 under-
lying storage and the amount of free memory. There is no default, but see reada-
head_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
file system); if this amount is more than 1/50th of total physical memory, reada-
head 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 ba-
sis 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" fol-
lowed 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 with-
out 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 file system inconsis-
tency is detected to be overridden.

preen_ok
This boolean relation overrides the default behavior controlling whether this file
system 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 op-
tions section) for this particular problem.

no_ok This boolean relation overrides the default behavior determining whether or not the
file system 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 file system problem should be suppressed when e2fsck is run-
ning in preen mode.

no_nomsg
This boolean relation overrides the default behavior controlling whether or not the
description for this file system 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 sys-
tem had a problem which has since been fixed. This is used for requests to opti-
mize 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 file system 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 path-
name 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 fol-
lowing date or time expressions should be expressed in UTC time instead of the lo-
cal 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 file
system contains orphaned files. (Of course, this is not always a good idea, since criti-
cal 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 sys-
tem, the date, and time: e.g., "e2fsck-sda3.server.INFO.20120314-112142". If the direc-
tory 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 sys-
tem 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).