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> [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, 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, 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
(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 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).
-v
(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
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.
