btrfs-search-metadata - Man Page

btrfs-search-metadata <subcommand> <args>

The btrfs-search-metadata program can be used to execute search queries in order to look up metadata items of an online, mounted btrfs filesystem. Unlike the btrfs inspect-internal dump-tree command, which directly reads from disk, btrfs-search-metadata only uses the kernel SEARCH ioctl function.

Besides being able to get any metadata slice from any tree, there are a number of convenience presets that execute predefined search queries.

-h,  --help

Show the built-in help message and exit.

--format keys|short|long

Print metadata items as keys only, as a short single line per item (default), or long output with full contents of all fields.

chunks <path>

Display all chunk items from the chunk tree, as well as the stripe items that they contain.

block_groups <path>

Display all block group items from the extent tree.

dev_extents <path>

Display all device extent items from the device tree.

file <path>

Display all information btrfs knows about a file or directory.

inode -t|--tree <tree> --inum <inum> <path>

Display all information about an inode number in a subvolume tree.

devices <path>

Display all device items from the device tree.

orphans <path>

Display all orphan items from the root tree.

dump -t|--tree <tree> [--min-key <MIN_KEY>] [--max-key <MAX_KEY>] <path>

Dump an arbitrary slice of metadata items from any tree. A key should be specified in the regular form as '(<objectid> <type> <offset>)', e.g. '(EXTENT_TREE ROOT_ITEM 0)'. The number -1 can be used instead of the maximum value for a field. This can be very useful when dumping all metadata items for a specific objectid. For example, what the inode subcommand does is searching with min-key '(<inum> 0 0)' and max-key '(<inum> -1 -1)'

block_group_contents --vaddr <vaddr> <path>

Dump the contents of a block group (from the extent tree) from the specified virtual address of the start of the block group to its end. Use the block_groups subcommand to list block group addresses.

block_group_free_space --vaddr <vaddr> <path>

Dump the free space extents for a block group (from the free space tree) for the block group at the specified virtual address. Use the block_groups subcommand to list block group addresses.

This program is an example of what can be done using the python-btrfs library.

Source and documentation on github: https://github.com/knorrie/python-btrfs