e2undo

replay ext filesystem undo logs

TLDR

Display undo file info

$ e2undo -h [path/to/undo_file] [/dev/sdXN]

Dry run showing candidate blocks

$ e2undo -nv [path/to/undo_file] [/dev/sdXN]

Perform undo operation

$ e2undo [path/to/undo_file] [/dev/sdXN]

Perform undo with verbose output

$ e2undo -v [path/to/undo_file] [/dev/sdXN]

Create backup undo file before overwriting

$ e2undo -z [path/to/file.e2undo] [path/to/undo_file] [/dev/sdXN]

SYNOPSIS

e2undo [options] undo-file device

e2undo replays undo logs for ext2/ext3/ext4 filesystems. This can reverse a failed or unwanted operation by e2fsprogs tools like e2fsck, resize2fs, or tune2fs, providing a safety mechanism for filesystem modifications.Undo files are created when these tools are run with the -z option. The undo file records all blocks modified during the operation, allowing precise rollback to the pre-operation state. This is particularly valuable when testing filesystem modifications or recovering from interrupted operations.

PARAMETERS

-f

Force the undo even when the filesystem UUID or superblock does not match the undo file

-h

Display information about the undo file without applying it

-n

Dry run: show what would be replayed without modifying the filesystem

-o offset

Byte offset of the filesystem within the device or image file

-v

Verbose output

-z file

Write a new undo file recording the blocks this undo operation overwrites

CAVEATS

Requires an undo file, which the e2fsprogs tools only create when run with their own -z option (for example `e2fsck -z undo.e2undo /dev/sda1`). The filesystem must be unmounted. e2undo refuses to run if the filesystem has changed since the undo file was written, unless -f is given, which risks corrupting the filesystem. Part of the e2fsprogs package.

RESOURCES

Source code · Homepage