btrfs-inspect-internal(8) — Linux manual page


BTRFS-INSPECT-INTE(8)         Btrfs Manual         BTRFS-INSPECT-INTE(8)

NAME         top

       btrfs-inspect-internal - query various internal information

SYNOPSIS         top

       btrfs inspect-internal <subcommand> <args>

DESCRIPTION         top

       This command group provides an interface to query internal
       information. The functionality ranges from a simple UI to an
       ioctl or a more complex query that assembles the result from
       several internal structures. The latter usually requires calls to
       privileged ioctls.

SUBCOMMAND         top

       dump-super [options] <device> [device...]
           (replaces the standalone tool btrfs-show-super)

           Show btrfs superblock information stored on given devices in
           textual form. By default the first superblock is printed,
           more details about all copies or additional backup data can
           be printed.

           Besides verification of the filesystem signature, there are
           no other sanity checks. The superblock checksum status is
           reported, the device item and filesystem UUIDs are checked
           and reported.

               the meaning of option -s has changed in version 4.8 to be
               consistent with other tools to specify superblock copy
               rather the offset. The old way still works, but prints a
               warning. Please update your scripts to use --bytenr
               instead. The option -i has been deprecated.

               print full superblock information, including the system
               chunk array and backup roots

               print information about all present superblock copies
               (cannot be used together with -s option)

           -i <super>
               (deprecated since 4.8, same behaviour as --super)

           --bytenr <bytenr>
               specify offset to a superblock in a non-standard location
               at bytenr, useful for debugging (disables the -f option)

               If there are multiple options specified, only the last
               one applies.

               attempt to print the superblock even if a valid BTRFS
               signature is not found; the result may be completely
               wrong if the data does not resemble a superblock

           -s|--super <bytenr>
               (see compatibility note above)

               specify which mirror to print, valid values are 0, 1 and
               2 and the superblock must be present on the device with a
               valid signature, can be used together with --force

       dump-tree [options] <device> [device...]
           (replaces the standalone tool btrfs-debug-tree)

           Dump tree structures from a given device in textual form,
           expand keys to human readable equivalents where possible.
           This is useful for analyzing filesystem state or
           inconsistencies and has a positive educational effect on
           understanding the internal filesystem structure.

               contains file names, consider that if you’re asked to
               send the dump for analysis. Does not contain file data.

               print only extent-related information: extent and device

               print only device-related information: tree root, chunk
               and device trees

               print only short root node information, ie. the root tree

               same as --roots plus print backup root info, ie. the
               backup root keys and the respective tree root block

               print only the uuid tree information, empty output if the
               tree does not exist

           -b <block_num>
               print info of the specified block only, can be specified
               multiple times

               use with -b, print all children tree blocks of

               (default up to 5.2)

               use depth-first search to print trees, the nodes and
               leaves are intermixed in the output

               (default since 5.3)

               use breadth-first search to print trees, the nodes are
               printed before all leaves

               print a placeholder HIDDEN instead of various names,
               useful for developers to inspect the dump while keeping
               potentially sensitive information hidden

               This is:

               •   directory entries (files, directories, subvolumes)

               •   default subvolume

               •   extended attributes (name, value)

               •   hardlink names (if stored inside another item or as
                   extended references in standalone items)

                       lengths are not hidden because they can be
                       calculated from the item size anyway.

               print b-tree node checksums stored in headers (metadata)

               print checksums stored in checksum items (data)

               do not automatically scan the system for other devices
               from the same filesystem, only use the devices provided
               as the arguments

           -t <tree_id>
               print only the tree with the specified ID, where the ID
               can be numerical or common name in a flexible human
               readable form

               The tree id name recognition rules:

               •   case does not matter

               •   the C source definition, eg. BTRFS_ROOT_TREE_OBJECTID

               •   short forms without BTRFS_ prefix, without _TREE and
                   _OBJECTID suffix, eg. ROOT_TREE, ROOT

               •   convenience aliases, eg. DEVICE for the DEV tree,
                   CHECKSUM for CSUM

               •   unrecognized ID is an error

       inode-resolve [-v] <ino> <path>
           (needs root privileges)

           resolve paths to all files with given inode number ino in a
           given subvolume at path, ie. all hardlinks


               (deprecated) alias for global -v option

       logical-resolve [-Pvo] [-s <bufsize>] <logical> <path>
           (needs root privileges)

           resolve paths to all files at given logical address in the
           linear filesystem space


               skip the path resolving and print the inodes instead

               ignore offsets, find all references to an extent instead
               of a single block. Requires kernel support for the V2
               ioctl (added in 4.15). The results might need further
               processing to filter out unwanted extents by the offset
               that is supposed to be obtained by other means.

           -s <bufsize>
               set internal buffer for storing the file names to
               bufsize, default is 64k, maximum 16m. Buffer sizes over
               64K require kernel support for the V2 ioctl (added in

               (deprecated) alias for global -v option

       min-dev-size [options] <path>
           (needs root privileges)

           return the minimum size the device can be shrunk to, without
           performing any resize operation, this may be useful before
           executing the actual resize operation


           --id <id>
               specify the device id to query, default is 1 if this
               option is not used

       rootid <path>
           for a given file or directory, return the containing tree
           root id, but for a subvolume itself return its own tree id
           (ie. subvol id)

               The result is undefined for the so-called empty
               subvolumes (identified by inode number 2), but such a
               subvolume does not contain any files anyway

       subvolid-resolve <subvolid> <path>
           (needs root privileges)

           resolve the absolute path of the subvolume id subvolid

       tree-stats [options] <device>
           (needs root privileges)

           Print sizes and statistics of trees.


               Print raw numbers in bytes.

EXIT STATUS         top

       btrfs inspect-internal returns a zero exit status if it succeeds.
       Non zero is returned in case of failure.

AVAILABILITY         top

       btrfs is part of btrfs-progs. Please refer to the btrfs wiki for further details.

SEE ALSO         top


COLOPHON         top

       This page is part of the btrfs-progs (btrfs filesystem tools)
       project.  Information about the project can be found at 
       If you have a bug report for this manual page, see
       This page was obtained from the project's upstream Git repository
       on 2024-06-14.  (At that time, the date of the most recent commit
       that was found in the repository was 2024-05-02.)  If you
       discover any rendering problems in this HTML version of the page,
       or you believe there is a better or more up-to-date source for
       the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original
       manual page), send a mail to

Btrfs v5.16.1                  02/06/2022          BTRFS-INSPECT-INTE(8)

Pages that refer to this page: btrfs(8)btrfs-select-super(8)