#! /usr/bin/env python class Tune2fs: """ Wrapper around Linux Ext2fs tool 'tune2fs' to adjust tunable filesystem parameters on ext2/ext3 filesystems """ # the following help texts have been taken from the # tune2fs(8) manpage marked February 2004 version 1.35 help_max_mount_counts = """ Adjust the maximal mounts count between two filesystem checks. If max-mount-counts is 0 then the number of times the filesystem is mounted will be disregarded by e2fsck(8) and the kernel. Staggering the mount-counts at which filesystems are forcibly checked will avoid all filesystems being checked at one time when using journaled filesystems. You should strongly consider the consequences of disabling mount-count-dependent checking entirely. Bad disk drives, cables, memory, and kernel bugs could all corrupt a filesystem without marking the filesystem dirty or in error. If you are using journaling on your filesystem, your filesystem will never be marked dirty, so it will not normally be checked. A filesys- tem error detected by the kernel will still force an fsck on the next reboot, but it may already be too late to prevent data loss at that point. See also the -i option for time-dependent checking. """ help_mount_count = """ Set the number of times the filesystem has been mounted. Can be used in conjunction with 'max_mount_counts' to force an fsck on the filesystem at the next reboot. """ help_error_behavior = """ Change the behavior of the kernel code when errors are detected. In all cases, a filesystem error will cause e2fsck(8) to check the filesystem on the next boot. error-behavior can be one of the following: -- continue : Continue normal execution. -- remount-ro : Remount filesystem read-only. -- panic : Cause a kernel panic. """ help_force = """ Force the tune2fs operation to complete even in the face of errors. This option is useful when removing the has_journal filesystem feature from a filesystem which has an external jour- nal (or is corrupted such that it appears to have an external journal), but that external journal is not available. WARNING: Removing an external journal from a filesystem which was not cleanly unmounted without first replaying the external journal can result in severe data loss and filesystem corrup- tion. """ help_group = """ Set the group which can use reserved filesystem blocks. The group parameter can be a numerical gid or a group name. If a group name is given, it is converted to a numerical gid before it is stored in the superblock. """ help_interval_between_checks = """ Adjust the maximal time between two filesystem checks. No post- fix or d result in days, m in months, and w in weeks. A value of zero will disable the time-dependent checking. It is strongly recommended that either -c (mount-count-depen- dent) or -i (time-dependent) checking be enabled to force peri- odic full e2fsck(8) checking of the filesystem. Failure to do so may lead to filesystem corruption due to bad disks, cables, memory, or kernel bugs to go unnoticed until they cause data loss or corruption. """ help_add_journal = """ Add an ext3 journal to the filesystem. If the -J option is not specified, the default journal parameters will be used to create an appropriately sized journal (given the size of the filesys- tem) stored within the filesystem. Note that you must be using a kernel which has ext3 support in order to actually make use of the journal. """ help_use_journal_size = """ Create a journal stored in the filesystem of size journal-size megabytes. The size of the journal must be at least 1024 filesystem blocks (i.e., 1MB if using 1k blocks, 4MB if using 4k blocks, etc.) and may be no more than 102,400 filesystem blocks. There must be enough free space in the filesystem to create a journal of that size. """ help_use_external_journal = """ Attach the filesystem to the journal block device located on external-journal. The external journal must have been already created using the command `mke2fs -O journal_dev external-journal` Note that external-journal must be formatted with the same block size as filesystems which will be using it. Instead of specifying a device name directly, exter- nal-journal can also be specified by either LABEL=label or UUID=UUID to locate the external journal by either the volume label or UUID stored in the ext2 superblock at the start of the journal. Use dumpe2fs(8) to display a journal device's volume label and UUID. See also the 'volume_label' option of tune2fs(8). """ help_reserved_blocks_percentage = """ Set the percentage of reserved filesystem blocks. """ help_last_mounted_directory = """ Set the last-mounted directory for the filesystem. """ help_enable_debug = """ Enable debugging code for this filesystem. """ help_enable_bsdgroups = """ Emulate BSD behaviour when creating new files: they will take the group-id of the directory in which they were created. The standard System V behaviour is the default, where newly created files take on the fsgid of the current process, unless the direc- try has the setgid bit set, in which case it takes the gid from the parent directory, and also gets the setgid bit set if it is directory itself. """ help_enable_user_xattr = """ Enable user-specified extended attributes. """ help_enable_acl = """ Enable Posix Access Control Lists. """ help_enable_uid16 = """ Disables 32-bit UIDs and GIDs. This is for interop- erability with older kernels which only store and expect 16-bit values. """ help_enable_journal_data = """ When the filesystem is mounted with journalling enabled, all data (not just metadata) is committed into the journal prior to being written into the main filesystem. """ help_enable_journal_data_ordered = """ When the filesystem is mounted with journalling enabled, all data is forced directly out to the main file system prior to its metadata being commutted to the journal. """ help_journal_data_writeback = """ When the filesystem is mounted with journalling enabled, data may be written into the main filesys- tem after its metadata has been commutted to the journal. This may increase throughput, however, it may allow old data to appear in files after a crash and journal recovery. """ help_reserved_blocks_count = """ Set the number of reserved filesystem blocks. """ help_time_last_checked = """ Set the time the filesystem was last checked using e2fsck. This can be useful in scripts which use a Logical Volume Manager to make a consistent snapshot of a filesystem, and then check the filesystem during off hours to make sure it hasn't been cor- rupted due to hardware problems, etc. If the filesystem was clean, then this option can be used to set the last checked time on the original filesystem. The format of time-last-checked is the international date format, with an optional time specifier, i.e. YYYYMMDD[[HHMM]SS]. The keyword now is also accepted, in which case the last checked time will be set to the current time. """ help_user = """ Set the user who can use the reserved filesystem blocks. user can be a numerical uid or a user name. If a user name is given, it is converted to a numerical uid before it is stored in the superblock. """ help_uuid = """ Set the universally unique identifier (UUID) of the filesystem to UUID. The format of the UUID is a series of hex digits sepa- rated by hyphens, like this: "c1b9d5a2-f162-11cf-9ece-0020afc76f16". The UUID parameter may also be one of the following: -- clear : clear the filesystem UUID -- random : generate a new randomly-generated UUID -- time : generate a new time-based UUID The UUID may be used by mount(8), fsck(8), and /etc/fstab(5) (and possibly others) by specifying UUID=uuid instead of a block special device name like /dev/hda1. See uuidgen(8) for more information. If the system does not have a good random number generator such as /dev/random or /dev/urandom, tune2fs will automatically use a time-based UUID instead of a randomly-generated UUID. """ help_authors = """ tune2fs was written by Remy Card . It is cur- rently being maintained by Theodore Ts'o . tune2fs uses the ext2fs library written by Theodore Ts'o . This manual page was written by Christian Kuhtz . Time-dependent checking was added by Uwe Ohse . """