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

           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

               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 offset

               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 <block_num>

               (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.

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

           -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 4.15).

               (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

               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 2020-09-18.  (At that time, the date of the most recent commit
       that was found in the repository was 2020-07-02.)  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

Btrfs v4.6.1                     07/14/2020            BTRFS-INSPECT-INTE(8)

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