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e2fsck.conf

Section: File Formats (5)
Updated: March 2018
Index Return to Main Contents

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 relation 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.
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).

This document was created by man2html, using the manual pages.
Time: 04:45:54 GMT, September 16, 2022 Content-type: text/html; charset=UTF-8 Man page of E2FSCK

E2FSCK

Section: Maintenance Commands (8)
Updated: March 2018
Index Return to Main Contents

NAME

e2fsck - check a Linux ext2/ext3/ext4 file system

SYNOPSIS

e2fsck [ -pacnyrdfkvtDFV ] [ -b superblock ] [ -B blocksize ] [ -l|-L bad_blocks_file ] [ -C fd ] [ -j external-journal ] [ -E extended_options ] [ -z undo_file ] device

DESCRIPTION

e2fsck is used to check the ext2/ext3/ext4 family of file systems. For ext3 and ext4 filesystems that use a journal, if the system has been shut down uncleanly without any errors, normally, after replaying the committed transactions in the journal, the file system should be marked as clean. Hence, for filesystems that use journalling, e2fsck will normally replay the journal and exit, unless its superblock indicates that further checking is required.

device is a block device (e.g., /dev/sdc1) or file containing the file system.

Note that in general it is not safe to run e2fsck on mounted filesystems. The only exception is if the -n option is specified, and -c, -l, or -L options are not specified. However, even if it is safe to do so, the results printed by e2fsck are not valid if the filesystem is mounted. If e2fsck asks whether or not you should check a filesystem which is mounted, the only correct answer is ``no''. Only experts who really know what they are doing should consider answering this question in any other way.

If e2fsck is run in interactive mode (meaning that none of -y, -n, or -p are specified), the program will ask the user to fix each problem found in the filesystem. A response of 'y' will fix the error; 'n' will leave the error unfixed; and 'a' will fix the problem and all subsequent problems; pressing Enter will proceed with the default response, which is printed before the question mark. Pressing Control-C terminates e2fsck immediately.

OPTIONS

-a

This option does the same thing as the -p option. It is provided for backwards compatibility only; it is suggested that people use -p option whenever possible.

-b superblock

Instead of using the normal superblock, use an alternative superblock specified by superblock. This option is normally used when the primary superblock has been corrupted. The location of backup superblocks is dependent on the filesystem's blocksize, the number of blocks per group, and features such as sparse_super.

Additional backup superblocks can be determined by using the mke2fs program using the -n option to print out where the superblocks exist, supposing mke2fs is supplied with arguments that are consistent with the filesystem's layout (e.g. blocksize, blocks per group, sparse_super, etc.).

If an alternative superblock is specified and the filesystem is not opened read-only, e2fsck will make sure that the primary superblock is updated appropriately upon completion of the filesystem check.

-B blocksize

Normally, e2fsck will search for the superblock at various different block sizes in an attempt to find the appropriate block size. This search can be fooled in some cases. This option forces e2fsck to only try locating the superblock at a particular blocksize. If the superblock is not found, e2fsck will terminate with a fatal error.

-c

This option causes e2fsck to use badblocks(8) program to do a read-only scan of the device in order to find any bad blocks. If any bad blocks are found, they are added to the bad block inode to prevent them from being allocated to a file or directory. If this option is specified twice, then the bad block scan will be done using a non-destructive read-write test.

-C fd

This option causes e2fsck to write completion information to the specified file descriptor so that the progress of the filesystem check can be monitored. This option is typically used by programs which are running e2fsck. If the file descriptor number is negative, then absolute value of the file descriptor will be used, and the progress information will be suppressed initially. It can later be enabled by sending the e2fsck process a SIGUSR1 signal. If the file descriptor specified is 0, e2fsck will print a completion bar as it goes about its business. This requires that e2fsck is running on a video console or terminal.

-d

Print debugging output (useless unless you are debugging e2fsck).

-D

Optimize directories in filesystem. This option causes e2fsck to try to optimize all directories, either by reindexing them if the filesystem supports directory indexing, or by sorting and compressing directories for smaller directories, or for filesystems using traditional linear directories.

Even without the -D option, e2fsck may sometimes optimize a few directories --- for example, if directory indexing is enabled and a directory is not indexed and would benefit from being indexed, or if the index structures are corrupted and need to be rebuilt. The -D option forces all directories in the filesystem to be optimized. This can sometimes make them a little smaller and slightly faster to search, but in practice, you should rarely need to use this option.

The -D option will detect directory entries with duplicate names in a single directory, which e2fsck normally does not enforce for performance reasons.

-E extended_options

Set e2fsck extended options. Extended options are comma separated, and may take an argument using the equals ('=') sign. The following options are supported:

ea_ver=extended_attribute_version: Set the version of the extended attribute blocks which e2fsck will require while checking the filesystem. The version number may be 1 or 2. The default extended attribute version format is 2.
journal_only: Only replay the journal if required, but do not perform any further checks or repairs.
fragcheck: During pass 1, print a detailed report of any discontiguous blocks for files in the filesystem.
discard: Attempt to discard free blocks and unused inode blocks after the full filesystem check (discarding blocks is useful on solid state devices and sparse / thin-provisioned storage). Note that discard is done in pass 5 AFTER the filesystem has been fully checked and only if it does not contain recognizable errors. However there might be cases where e2fsck does not fully recognize a problem and hence in this case this option may prevent you from further manual data recovery.
nodiscard: Do not attempt to discard free blocks and unused inode blocks. This option is exactly the opposite of discard option. This is set as default.
no_optimize_extents: Do not offer to optimize the extent tree by eliminating unnecessary width or depth. This can also be enabled in the options section of /etc/e2fsck.conf.
optimize_extents: Offer to optimize the extent tree by eliminating unnecessary width or depth. This is the default unless otherwise specified in /etc/e2fsck.conf.
inode_count_fullmap: 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 optimization can also be enabled in the options section of /etc/e2fsck.conf.
no_inode_count_fullmap: Disable the inode_count_fullmap optimization. This is the default unless otherwise specified in /etc/e2fsck.conf.
readahead_kb: Use this many KiB of memory to pre-fetch metadata in the hopes of reducing e2fsck runtime. By default, this is set to 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. Set this to zero to disable readahead entirely.
bmap2extent: Convert block-mapped files to extent-mapped files.
fixes_only: Only fix damaged metadata; do not optimize htree directories or compress extent trees. This option is incompatible with the -D and -E bmap2extent options.

-f

Force checking even if the file system seems clean.

-F

Flush the filesystem device's buffer caches before beginning. Only really useful for doing e2fsck time trials.

-j external-journal

Set the pathname where the external-journal for this filesystem can be found.

-k

When combined with the -c option, any existing bad blocks in the bad blocks list are preserved, and any new bad blocks found by running badblocks(8) will be added to the existing bad blocks list.

-l filename

Add the block numbers listed in the file specified by filename to the list of bad blocks. The format of this file is the same as the one generated by the badblocks(8) program. Note that the block numbers are based on the blocksize of the filesystem. Hence, badblocks(8) must be given the blocksize of the filesystem in order to obtain correct results. As a result, it is much simpler and safer to use the -c option to e2fsck, since it will assure that the correct parameters are passed to the badblocks program.

-L filename

Set the bad blocks list to be the list of blocks specified by filename. (This option is the same as the -l option, except the bad blocks list is cleared before the blocks listed in the file are added to the bad blocks list.)

-n

Open the filesystem read-only, and assume an answer of `no' to all questions. Allows e2fsck to be used non-interactively. This option may not be specified at the same time as the -p or -y options.

-p

Automatically repair ("preen") the file system. This option will cause e2fsck to automatically fix any filesystem problems that can be safely fixed without human intervention. If e2fsck discovers a problem which may require the system administrator to take additional corrective action, e2fsck will print a description of the problem and then exit with the value 4 logically or'ed into the exit code. (See the EXIT CODE section.) This option is normally used by the system's boot scripts. It may not be specified at the same time as the -n or -y options.

-r

This option does nothing at all; it is provided only for backwards compatibility.

-t

Print timing statistics for e2fsck. If this option is used twice, additional timing statistics are printed on a pass by pass basis.

-v

Verbose mode.

-V

Print version information and exit.

-y

Assume an answer of `yes' to all questions; allows e2fsck to be used non-interactively. This option may not be specified at the same time as the -n or -p options.

-z undo_file

Before overwriting a file system block, write the old contents of the block to an undo file. This undo file can be used with e2undo(8) to restore the old contents of the file system should something go wrong. If the empty string is passed as the undo_file argument, the undo file will be written to a file named e2fsck-device.e2undo in the directory specified via the E2FSPROGS_UNDO_DIR environment variable.

WARNING: The undo file cannot be used to recover from a power or system crash.

EXIT CODE

The exit code returned by e2fsck is the sum of the following conditions:
0 - No errors
1 - File system errors corrected
2 - File system errors corrected, system should
be rebooted
4 - File system errors left uncorrected
8 - Operational error
16 - Usage or syntax error
32 - E2fsck canceled by user request
128 - Shared library error

SIGNALS

The following signals have the following effect when sent to e2fsck.

SIGUSR1: This signal causes e2fsck to start displaying a completion bar or emitting progress information. (See discussion of the -C option.)
SIGUSR2: This signal causes e2fsck to stop displaying a completion bar or emitting progress information.

REPORTING BUGS

Almost any piece of software will have bugs. If you manage to find a filesystem which causes e2fsck to crash, or which e2fsck is unable to repair, please report it to the author.

Please include as much information as possible in your bug report. Ideally, include a complete transcript of the e2fsck run, so I can see exactly what error messages are displayed. (Make sure the messages printed by e2fsck are in English; if your system has been configured so that e2fsck's messages have been translated into another language, please set the the LC_ALL environment variable to C so that the transcript of e2fsck's output will be useful to me.) If you have a writable filesystem where the transcript can be stored, the script(1) program is a handy way to save the output of e2fsck to a file.

It is also useful to send the output of dumpe2fs(8). If a specific inode or inodes seems to be giving e2fsck trouble, try running the debugfs(8) command and send the output of the stat(1u) command run on the relevant inode(s). If the inode is a directory, the debugfs dump command will allow you to extract the contents of the directory inode, which can sent to me after being first run through uuencode(1). The most useful data you can send to help reproduce the bug is a compressed raw image dump of the filesystem, generated using e2image(8). See the e2image(8) man page for more details.

Always include the full version string which e2fsck displays when it is run, so I know which version you are running.

ENVIRONMENT

E2FSCK_CONFIG: Determines the location of the configuration file (see e2fsck.conf(5)).

AUTHOR

This version of e2fsck was written by Theodore Ts'o <tytso@mit.edu>.

Index

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
EXIT CODE
SIGNALS
REPORTING BUGS
ENVIRONMENT
AUTHOR
SEE ALSO

This document was created by man2html, using the manual pages.
Time: 04:46:00 GMT, September 16, 2022

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[MAN] e2fsck

e2fsck.conf

NAME

DESCRIPTION

THE [options] STANZA

THE [defaults] STANZA

THE [problems] STANZA

THE [scratch_files] STANZA

LOGGING

EXAMPLES

FILES

SEE ALSO

Index

E2FSCK

NAME

SYNOPSIS

DESCRIPTION

OPTIONS

EXIT CODE

SIGNALS

REPORTING BUGS

ENVIRONMENT

AUTHOR

SEE ALSO

Index

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