1 .TH BTRFS 8 "" "btrfs" "btrfs"
3 .\" Man page written by Goffredo Baroncelli <kreijack@inwind.it> (Feb 2010)
6 btrfs \- control a btrfs filesystem
8 \fBbtrfs\fP \fBsubvolume snapshot\fP\fI [-r] <source> [<dest>/]<name>\fP
10 \fBbtrfs\fP \fBsubvolume delete\fP\fI <subvolume>\fP
12 \fBbtrfs\fP \fBsubvolume create\fP\fI [<dest>/]<name>\fP
14 \fBbtrfs\fP \fBsubvolume list\fP\fI [-p] <path>\fP
16 \fBbtrfs\fP \fBsubvolume set-default\fP\fI <id> <path>\fP
18 \fBbtrfs\fP \fBsubvolume get-default\fP\fI <path>\fP
20 \fBbtrfs\fP \fBfilesystem defragment\fP -c[zlib|lzo] [-l \fIlen\fR] \
21 [-s \fIstart\fR] [-t \fIsize\fR] -[vf] <\fIfile\fR>|<\fIdir\fR> \
22 [<\fIfile\fR>|<\fIdir\fR>...]
24 \fBbtrfs\fP \fBfilesystem sync\fP\fI <path> \fP
26 \fBbtrfs\fP \fBfilesystem resize\fP\fI [devid:][+/\-]<size>[gkm]|[devid:]max <filesystem>\fP
28 \fBbtrfs\fP \fBfilesystem label\fP\fI <dev> [newlabel]\fP
30 \fBbtrfs\fP \fBsubvolume find-new\fP\fI <subvolume> <last_gen>\fP
32 \fBbtrfs\fP \fBfilesystem balance\fP\fI <path> \fP
34 \fBbtrfs\fP \fBdevice scan\fP\fI [--all-devices|<device> [<device>...]]\fP
36 \fBbtrfs\fP \fBdevice show\fP\fI [--all-devices|<uuid>|<label>]\fP
38 \fBbtrfs\fP \fBdevice add\fP\fI <device> [<device>...] <path> \fP
40 \fBbtrfs\fP \fBdevice delete\fP\fI <device> [<device>...] <path> \fP
42 \fBbtrfs\fP \fBscrub start\fP [-Bdqru] {\fI<path>\fP|\fI<device>\fP}
44 \fBbtrfs\fP \fBscrub cancel\fP {\fI<path>\fP|\fI<device>\fP}
46 \fBbtrfs\fP \fBscrub resume\fP [-Bdqru] {\fI<path>\fP|\fI<device>\fP}
48 \fBbtrfs\fP \fBscrub status\fP [-d] {\fI<path>\fP|\fI<device>\fP}
50 \fBbtrfs\fP \fBinspect-internal inode-resolve\fP [-v] \fI<inode>\fP \fI<path>\fP
52 \fBbtrfs\fP \fBinspect-internal logical-resolve\fP
53 [-Pv] \fI<logical>\fP \fI<path>\fP
55 \fBbtrfs\fP \fBhelp|\-\-help|\-h \fP\fI\fP
57 \fBbtrfs\fP \fB<command> \-\-help \fP\fI\fP
61 is used to control the filesystem and the files and directories stored. It is
62 the tool to create or destroy a snapshot or a subvolume for the
63 filesystem, to defrag a file or a directory, flush the data to the disk,
64 to resize the filesystem, to scan the device.
66 It is possible to abbreviate the commands unless the commands are ambiguous.
67 For example: it is possible to run
70 .I btrfs subvolume snapshot.
73 is not allowed, because
75 may be interpreted both as
81 returns filesystem sync
82 If a command is terminated by
84 , the detailed help is showed. If the passed command matches more commands,
85 detailed help of all the matched commands is showed. For example
94 \fBsubvolume snapshot\fR\fI [-r] <source> [<dest>/]<name>\fR
95 Create a writable/readonly snapshot of the subvolume \fI<source>\fR with the
96 name \fI<name>\fR in the \fI<dest>\fR directory. If \fI<source>\fR is not a
97 subvolume, \fBbtrfs\fR returns an error. If \fI-r\fR is given, the snapshot
101 \fBsubvolume delete\fR\fI <subvolume>\fR
102 Delete the subvolume \fI<subvolume>\fR. If \fI<subvolume>\fR is not a
103 subvolume, \fBbtrfs\fR returns an error.
106 \fBsubvolume create\fR\fI [<dest>/]<name>\fR
107 Create a subvolume in \fI<dest>\fR (or in the current directory if
108 \fI<dest>\fR is omitted).
111 \fBsubvolume list\fR\fI [-p] <path>\fR
112 List the subvolumes present in the filesystem \fI<path>\fR. For every
113 subvolume the following information is shown by default.
114 ID <ID> top level <ID> path <path>
115 where path is the relative path of the subvolume to the \fItop level\fR
117 The subvolume's ID may be used by the \fBsubvolume set-default\fR command, or
118 at mount time via the \fIsubvol=\fR option.
119 If \fI-p\fR is given, then \fIparent <ID>\fR is added to the output between ID
120 and top level. The parent's ID may be used at mount time via the
121 \fIsubvolrootid=\fR option.
124 \fBsubvolume set-default\fR\fI <id> <path>\fR
125 Set the subvolume of the filesystem \fI<path>\fR which is mounted as
126 \fIdefault\fR. The subvolume is identified by \fI<id>\fR, which
127 is returned by the \fBsubvolume list\fR command.
130 \fBsubvolume get-default\fR\fI <path>\fR
131 Get the default subvolume of the filesystem \fI<path>\fR. The output format
132 is similar to \fBsubvolume list\fR command.
135 \fBfilesystem defragment\fP -c[zlib|lzo] [-l \fIlen\fR] [-s \fIstart\fR] \
136 [-t \fIsize\fR] -[vf] <\fIfile\fR>|<\fIdir\fR> [<\fIfile\fR>|<\fIdir\fR>...]
138 Defragment file data and/or directory metadata. To defragment all files in a
139 directory you have to specify each one on its own or use your shell wildcards.
141 The start position and the number of bytes to defragment can be specified by
142 \fIstart\fR and \fIlen\fR. Any extent bigger than threshold will be
143 considered already defragged. Use 0 to take the kernel default, and use 1 to
144 say every single extent must be rewritten. You can also turn on compression in
145 defragment operations.
149 \fB-c\fP compress file contents while defragmenting
151 \fB-f\fP flush filesystem after defragmenting
153 \fB-s start\fP defragment only from byte \fIstart\fR onward
155 \fB-l len\fP defragment only up to \fIlen\fR bytes
157 \fB-t size\fP defragment only files at least \fIsize\fR bytes big
159 NOTE: defragmenting with kernels up to 2.6.37 will unlink COW-ed copies of data,
160 don't use it if you use snapshots, have de-duplicated your data or made
161 copies with \fBcp --reflink\fP.
164 \fBsubvolume find-new\fR\fI <subvolume> <last_gen>\fR
165 List the recently modified files in a subvolume, after \fI<last_gen>\fR ID.
168 \fBfilesystem sync\fR\fI <path> \fR
169 Force a sync for the filesystem identified by \fI<path>\fR.
173 .\" Some wording are extracted by the resize2fs man page
176 \fBfilesystem resize\fR\fI [devid:][+/\-]<size>[gkm]|[devid:]max <path>\fR
177 Resize a filesystem identified by \fI<path>\fR for the underlying device
178 \fIdevid\fR. The \fIdevid\fR can be found with \fBbtrfs filesystem show\fR and
179 defaults to 1 if not specified.
180 The \fI<size>\fR parameter specifies the new size of the filesystem.
181 If the prefix \fI+\fR or \fI\-\fR is present the size is increased or decreased
182 by the quantity \fI<size>\fR.
183 If no units are specified, the unit of the \fI<size>\fR parameter defaults to
184 bytes. Optionally, the size parameter may be suffixed by one of the following
185 units designators: 'K', 'M', or 'G', kilobytes, megabytes, or gigabytes,
188 If 'max' is passed, the filesystem will occupy all available space on the
191 The \fBresize\fR command \fBdoes not\fR manipulate the size of underlying
192 partition. If you wish to enlarge/reduce a filesystem, you must make sure you
193 can expand the partition before enlarging the filesystem and shrink the
194 partition after reducing the size of the filesystem. This can done using
195 \fBfdisk(8)\fR or \fBparted(8)\fR to delete the existing partition and recreate
196 it with the new desired size. When recreating the partition make sure to use
197 the same starting disk cylinder as before.
200 \fBfilesystem label\fP\fI <dev> [newlabel]\fP
201 Show or update the label of a filesystem. \fI<dev>\fR is used to identify the
203 If a \fInewlabel\fR optional argument is passed, the label is changed. The
204 following constraints exist for a label:
206 - the maximum allowable length shall be less or equal than 256 chars
208 - the label shall not contain the '/' or '\\' characters.
210 NOTE: Currently there are the following limitations:
212 - the filesystem has to be unmounted
214 - the filesystem should not have more than one device.
217 \fBfilesystem show\fR [--all-devices|<uuid>|<label>]\fR
218 Show the btrfs filesystem with some additional info. If no \fIUUID\fP or
219 \fIlabel\fP is passed, \fBbtrfs\fR show info of all the btrfs filesystem.
220 If \fB--all-devices\fP is passed, all the devices under /dev are scanned;
221 otherwise the devices list is extracted from the /proc/partitions file.
224 \fBfilesystem balance\fR \fI<path>\fR
225 Balance the chunks of the filesystem identified by \fI<path>\fR
229 \fBdevice add\fR\fI <dev> [<dev>..] <path>\fR
230 Add device(s) to the filesystem identified by \fI<path>\fR.
233 \fBdevice delete\fR\fI <dev> [<dev>..] <path>\fR
234 Remove device(s) from a filesystem identified by \fI<path>\fR.
237 \fBdevice scan\fR \fI[--all-devices|<device> [<device>...]\fR
238 If one or more devices are passed, these are scanned for a btrfs filesystem.
239 If no devices are passed, \fBbtrfs\fR scans all the block devices listed
240 in the /proc/partitions file.
241 Finally, if \fB--all-devices\fP is passed, all the devices under /dev are
245 \fBscrub start\fP [-Bdqru] {\fI<path>\fP|\fI<device>\fP}
246 Start a scrub on all devices of the filesystem identified by \fI<path>\fR or on
247 a single \fI<device>\fR. Without options, scrub is started as a background
248 process. Progress can be obtained with the \fBscrub status\fR command. Scrubbing
249 involves reading all data from all disks and verifying checksums. Errors are
250 corrected along the way if possible.
255 Do not background and print scrub statistics when finished.
257 Print separate statistics for each device of the filesystem (-B only).
259 Quiet. Omit error messages and statistics.
261 Read only mode. Do not attempt to correct anything.
263 Scrub unused space as well. (NOT IMPLEMENTED)
267 \fBscrub cancel\fP {\fI<path>\fP|\fI<device>\fP}
268 If a scrub is running on the filesystem identified by \fI<path>\fR, cancel it.
269 Progress is saved in the scrub progress file and scrubbing can be resumed later
270 using the \fBscrub resume\fR command.
271 If a \fI<device>\fR is given, the corresponding filesystem is found and
272 \fBscrub cancel\fP behaves as if it was called on that filesystem.
275 \fBscrub resume\fP [-Bdqru] {\fI<path>\fP|\fI<device>\fP}
276 Resume a canceled or interrupted scrub cycle on the filesystem identified by
277 \fI<path>\fR or on a given \fI<device>\fR. Does not start a new scrub if the
278 last scrub finished successfully.
283 see \fBscrub start\fP.
287 \fBscrub status\fP [-d] {\fI<path>\fP|\fI<device>\fP}
288 Show status of a running scrub for the filesystem identified by \fI<path>\fR or
289 for the specified \fI<device>\fR.
290 If no scrub is running, show statistics of the last finished or canceled scrub
291 for that filesystem or device.
296 Print separate statistics for each device of the filesystem.
300 \fBinspect-internal inode-resolve\fP [-v] \fI<inode>\fP \fI<path>\fP
301 Resolves an <inode> in subvolume <path> to all filesystem paths.
306 verbose mode. print count of returned paths and ioctl() return value
310 \fBinspect-internal logical-resolve\fP [-Pv] \fI<logical>\fP \fI<path>\fP
311 Resolves a <logical> address in the filesystem mounted at <path> to all inodes.
312 By default, each inode is then resolved to a file system path (similar to the
313 \fBinode-resolve\fP subcommand).
318 skip the path resolving and print the inodes instead
320 verbose mode. print count of returned paths and all ioctl() return values
324 \fBbtrfs\fR returns a zero exist status if it succeeds. Non zero is returned in
329 is part of btrfs-progs. Btrfs filesystem is currently under heavy development,
330 and not suitable for any uses other than benchmarking and review.
331 Please refer to the btrfs wiki http://btrfs.wiki.kernel.org for