btrfs-inspect-internal

BTRFS-INSPECT-INTERNAL(8) BTRFS BTRFS-INSPECT-INTERNAL(8)

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...]
          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> [device...]
          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, i.e. the root tree keys

          -R|--backups
                 same as --roots plus print backup root info, i.e. 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, can be specified multiple times

          --follow
                 use with -b, print all children tree blocks of <block_num>

          --dfs  (default up to 5.2)

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

          --bfs  (default since 5.3)

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

          --hide-names
                 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)

                 NOTE:
                    Lengths are not hidden because they can be calculated from the item size anyway.

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

          --csum-items
                 print checksums stored in checksum items (data)

          --noscan
                 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, e.g. BTRFS_ROOT_TREE_OBJECTID

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

                 • convenience aliases, e.g. 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, i.e. all hardlinks

          Options

          -v     (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

          Options

          -P     skip the path resolving and print the inodes instead

          -o     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 re‐
                 sults 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 64KiB, maximum 16MiB.  Buffer sizes over 64Kib require kernel support for
                 the V2 ioctl (added in 4.15).

          -v     (deprecated) alias for global -v option

   map-swapfile [options] <file>
          (needs root privileges)

          Find  device-specific physical offset of file that can be used for hibernation. Also verify that the file is suitable as a swapfile.  See also command
          btrfs filesystem mkswapfile and the Swapfile feature description.

          NOTE:
             Do not use filefrag or FIEMAP ioctl values reported as physical, this is different due to internal filesystem mappings.   The  hibernation  expects
             offset relative to the physical block device.

          Options

          -r|--resume-offset
                 print only the value suitable as resume offset for file /sys/power/resume_offset

   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 (i.e. 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. This takes a device as an argument and not a mount point unlike other commands.

          NOTE:
             In case the the filesystem is still mounted it's possible to run the command but the results may be inaccurate or various errors may be printed  in
             case there are ongoing writes to the filesystem. A warning is printed in such case.

          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 documentation at https://btrfs.readthedocs.io or wiki http://btrfs.wiki.kernel.org for further informa‐
   tion.