E2fsprogs version 1.46-WIP
dumpe2fs - dump ext2/ext3/ext4 filesystem information
dumpe2fs [ -bfghixV ] [ -o superblock=superblock ] [ -o blocksize=blocksize ] device
dumpe2fs prints the super block and blocks group information for the filesystem present on device.
Note: When used with a mounted filesystem, the printed information may be old or inconsistent.
|-b||print the blocks which are reserved as bad in the filesystem.|
|use the block superblock when examining the filesystem. This option is not usually needed except by a filesystem wizard who is examining the remains of a very badly corrupted filesystem.|
|use blocks of blocksize bytes when examining the filesystem. This option is not usually needed except by a filesystem wizard who is examining the remains of a very badly corrupted filesystem.|
|-f||force dumpe2fs to display a filesystem even though it may have some filesystem feature flags which dumpe2fs may not understand (and which can cause some of dumpe2fs’s display to be suspect).|
|-g||display the group descriptor information in a machine readable colon-separated value format. The fields displayed are the group number; the number of the first block in the group; the superblock location (or -1 if not present); the range of blocks used by the group descriptors (or -1 if not present); the block bitmap location; the inode bitmap location; and the range of blocks used by the inode table.|
|-h||only display the superblock information and not any of the block group descriptor detail information.|
|-i||display the filesystem data from an image file created by e2image, using device as the pathname to the image file.|
|-m||If the mmp feature is enabled on the filesystem, check if device is in use by another node, see e2mmpstatus(8) for full details. If used together with the -i option, only the MMP block information is printed.|
|-x||print the detailed group information block numbers in hexadecimal format|
|-V||print the version number of dumpe2fs and exit.|
dumpe2fs exits with a return code of 0 if the operation completed without errors. It will exit with a non-zero return code if there are any errors, such as problems reading a valid superblock, bad checksums, or if the device is in use by another node and -m is specified.
You may need to know the physical filesystem structure to understand the output.
dumpe2fs is part of the e2fsprogs package and is available from http://e2fsprogs.sourceforge.net.