NAME

       btrfs-inspect-internal - query various internal information

SYNOPSIS

       btrfs inspect-internal <subcommand> <args>

DESCRIPTION

       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

       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.

               Note
               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.
           Options

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

           -a|--all
               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.

           -F|--force
               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>
           (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.

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

           -e|--extents
               print only extent-related information: extent and device trees

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

           -r|--roots
               print only short root node information, ie. the root tree keys

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

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

           -b <block_num>
               print info of the specified block only

           -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

           Options

           -v
               verbose mode, print count of returned paths and ioctl() return value

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

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

           Options

           -P
               skip the path resolving and print the inodes instead

           -v
               verbose mode, print count of returned paths and all ioctl() return values

           -s <bufsize>
               set internal buffer for storing the file names to bufsize, default is 4096,
               maximum 64k

       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

           Options

           --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)

               Note
               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.

           Options

           -b
               Print raw numbers in bytes.

EXIT STATUS

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

AVAILABILITY

       btrfs is part of btrfs-progs. Please refer to the btrfs wiki http://btrfs.wiki.kernel.org
       for further details.

SEE ALSO

       mkfs.btrfs(8)