dumpe2fs
Display ext2/3/4 filesystem information
TLDR
Display ext2, ext3 and ext4 filesystem information
Display the blocks which are reserved as bad in the filesystem
Force display filesystem information even with unrecognizable feature flags
Only display the superblock information and not any of the block group descriptor detail information
Print the detailed group information block numbers in hexadecimal format
SYNOPSIS
dumpe2fs [-bhixV] [-o superblock=superblock] [-o blocksize=blocksize] device
PARAMETERS
-b
Display blocks reserved for bad blocks.
-h
Only display the superblock information and not the block group descriptors.
-i
Display filesystem information from an image file instead of directly from a device.
-o superblock=superblock
Use the specified superblock to examine the filesystem.
-o blocksize=blocksize
Use the specified blocksize when examining the filesystem.
-V
Display version information and exit.
-x
Print the block group and superblock data in hexadecimal format.
device
The block device or filesystem image file to examine.
DESCRIPTION
dumpe2fs is a command-line utility used to display superblock and block group information for ext2, ext3, and ext4 filesystems. It provides a detailed view of the filesystem's metadata, which is useful for troubleshooting, recovering corrupted filesystems, and understanding the underlying structure.
It reveals essential parameters such as block size, inode count, creation time, last mount time, and features enabled. By examining the block group descriptors, dumpe2fs reveals how the filesystem is organized into block groups, each containing inodes, data blocks, and bitmaps. It's a valuable tool for system administrators and advanced users to understand and diagnose filesystem-related problems.
It is a read-only operation that does not modify the filesystem itself.
CAVEATS
dumpe2fs should only be used on unmounted or read-only mounted filesystems to prevent inconsistencies in the output.
<B>INTERPRETING OUTPUT</B>
The output of dumpe2fs can be quite verbose. Pay close attention to the superblock information, which includes essential filesystem parameters. The block group descriptors provide details about the allocation of inodes and blocks within each group.
Understanding these details is crucial for filesystem analysis and recovery.
<B>IMAGE FILES</B>
The -i option allows examining filesystem images created using tools like dd. This is valuable for analyzing filesystems from backups or disk images.
HISTORY
dumpe2fs was developed alongside the ext2 filesystem in the early 1990s as a debugging and diagnostic tool. As ext3 and ext4 evolved, dumpe2fs was updated to support these newer filesystem formats, remaining a core utility for filesystem administration and troubleshooting.
