1BTRFS-INSPECT-INTE(8) Btrfs Manual BTRFS-INSPECT-INTE(8)
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6 btrfs-inspect-internal - query various internal information
7
9 btrfs inspect-internal <subcommand> <args>
10
12 This command group provides an interface to query internal information.
13 The functionality ranges from a simple UI to an ioctl or a more complex
14 query that assembles the result from several internal structures. The
15 latter usually requires calls to privileged ioctls.
16
18 dump-super [options] <device> [device...]
19 (replaces the standalone tool btrfs-show-super)
20 Show btrfs superblock information stored on given devices in
22 textual form. By default the first superblock is printed, more
23 details about all copies or additional backup data can be printed.
24 Besides verification of the filesystem signature, there are no
26 other sanity checks. The superblock checksum status is reported,
27 the device item and filesystem UUIDs are checked and reported.
28 Note
30 the meaning of option -s has changed in version 4.8 to be
31 consistent with other tools to specify superblock copy rather
32 the offset. The old way still works, but prints a warning.
33 Please update your scripts to use --bytenr instead. The option
34 -i has been deprecated.
35 Options
36 -f|--full
38 print full superblock information, including the system chunk
39 array and backup roots
40 -a|--all
42 print information about all present superblock copies (cannot
43 be used together with -s option)
44 -i <super>
46 (deprecated since 4.8, same behaviour as --super)
47 --bytenr <bytenr>
49 specify offset to a superblock in a non-standard location at
50 bytenr, useful for debugging (disables the -f option)
51 If there are multiple options specified, only the last one
53 applies.
54 -F|--force
56 attempt to print the superblock even if a valid BTRFS signature
57 is not found; the result may be completely wrong if the data
58 does not resemble a superblock
59 -s|--super <bytenr>
61 (see compatibility note above)
62 specify which mirror to print, valid values are 0, 1 and 2 and
64 the superblock must be present on the device with a valid
65 signature, can be used together with --force
66 dump-tree [options] <device> [device...]
68 (replaces the standalone tool btrfs-debug-tree)
69 Dump tree structures from a given device in textual form, expand
71 keys to human readable equivalents where possible. This is useful
72 for analyzing filesystem state or inconsistencies and has a
73 positive educational effect on understanding the internal
74 filesystem structure.
75 Note
77 contains file names, consider that if you’re asked to send the
78 dump for analysis. Does not contain file data.
79 Options
80 -e|--extents
82 print only extent-related information: extent and device trees
83 -d|--device
85 print only device-related information: tree root, chunk and
86 device trees
87 -r|--roots
89 print only short root node information, ie. the root tree keys
90 -R|--backups
92 same as --roots plus print backup root info, ie. the backup
93 root keys and the respective tree root block offset
94 -u|--uuid
96 print only the uuid tree information, empty output if the tree
97 does not exist
98 -b <block_num>
100 print info of the specified block only, can be specified
101 multiple times
102 --follow
104 use with -b, print all children tree blocks of <block_num>
105 --dfs
107 (default up to 5.2)
108 use depth-first search to print trees, the nodes and leaves are
110 intermixed in the output
111 --bfs
113 (default since 5.3)
114 use breadth-first search to print trees, the nodes are printed
116 before all leaves
117 --hide-names
119 print a placeholder HIDDEN instead of various names, useful for
120 developers to inspect the dump while keeping potentially
121 sensitive information hidden
122 This is:
124 · directory entries (files, directories, subvolumes)
126 · default subvolume
128 · extended attributes (name, value)
130 · hardlink names (if stored inside another item or as
132 extended references in standalone items)
133 Note
135 lengths are not hidden because they can be calculated
136 from the item size anyway.
137 --noscan
139 do not automatically scan the system for other devices from the
140 same filesystem, only use the devices provided as the arguments
141 -t <tree_id>
143 print only the tree with the specified ID, where the ID can be
144 numerical or common name in a flexible human readable form
145 The tree id name recognition rules:
147 · case does not matter
149 · the C source definition, eg. BTRFS_ROOT_TREE_OBJECTID
151 · short forms without BTRFS_ prefix, without _TREE and
153 _OBJECTID suffix, eg. ROOT_TREE, ROOT
154 · convenience aliases, eg. DEVICE for the DEV tree, CHECKSUM
156 for CSUM
157 · unrecognized ID is an error
159 inode-resolve [-v] <ino> <path>
161 (needs root privileges)
162 resolve paths to all files with given inode number ino in a given
164 subvolume at path, ie. all hardlinks
165 Options
167 -v
169 verbose mode, print count of returned paths and ioctl() return
170 value
171 logical-resolve [-Pvo] [-s <bufsize>] <logical> <path>
173 (needs root privileges)
174 resolve paths to all files at given logical address in the linear
176 filesystem space
177 Options
179 -P
181 skip the path resolving and print the inodes instead
182 -v
184 verbose mode, print count of returned paths and all ioctl()
185 return values
186 -o
188 ignore offsets, find all references to an extent instead of a
189 single block. Requires kernel support for the V2 ioctl (added
190 in 4.15). The results might need further processing to filter
191 out unwanted extents by the offset that is supposed to be
192 obtained by other means.
193 -s <bufsize>
195 set internal buffer for storing the file names to bufsize,
196 default is 64k, maximum 16m. Buffer sizes over 64K require
197 kernel support for the V2 ioctl (added in 4.15).
198 min-dev-size [options] <path>
200 (needs root privileges)
201 return the minimum size the device can be shrunk to, without
203 performing any resize operation, this may be useful before
204 executing the actual resize operation
205 Options
207 --id <id>
209 specify the device id to query, default is 1 if this option is
210 not used
211 rootid <path>
213 for a given file or directory, return the containing tree root id,
214 but for a subvolume itself return its own tree id (ie. subvol id)
215 Note
217 The result is undefined for the so-called empty subvolumes
218 (identified by inode number 2), but such a subvolume does not
219 contain any files anyway
220 subvolid-resolve <subvolid> <path>
222 (needs root privileges)
223 resolve the absolute path of the subvolume id subvolid
225 tree-stats [options] <device>
227 (needs root privileges)
228 Print sizes and statistics of trees.
230 Options
232 -b
234 Print raw numbers in bytes.
235
237 btrfs inspect-internal returns a zero exit status if it succeeds. Non
238 zero is returned in case of failure.
239
241 btrfs is part of btrfs-progs. Please refer to the btrfs wiki
242 http://btrfs.wiki.kernel.org for further details.
243
245 mkfs.btrfs(8)
246Btrfs v5.6 04/05/2020 BTRFS-INSPECT-INTE(8)