btrfs-show-super(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...]
(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 verifictaion 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 thre’s no valid BTRFS
signature found, the result may be completely wrong if the data
do 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,
for a subvolume itself return it’s own tree id (ie. subvol id)
Note
The result is undefined for the so-called empty subvolumes
(identified by inode number 2), but such subvolume does not
contain any files anyway
subvolid-resolve <subvolid> <path>
(needs root privileges)
resolve the absolute path of a 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)
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