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> [<subvolume>...]\fP
12 \fBbtrfs\fP \fBsubvolume create\fP\fI [<dest>/]<name>\fP
14 \fBbtrfs\fP \fBsubvolume list\fP\fI [-aprts] [-g [+|-]value] [-c [+|-]value] [--rootid=rootid,gen,ogen,path] <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 add\fP\fI <device> [<device>...] <path> \fP
38 \fBbtrfs\fP \fBdevice delete\fP\fI <device> [<device>...] <path> \fP
40 \fBbtrfs\fP \fBscrub start\fP [-Bdqru] {\fI<path>\fP|\fI<device>\fP}
42 \fBbtrfs\fP \fBscrub cancel\fP {\fI<path>\fP|\fI<device>\fP}
44 \fBbtrfs\fP \fBscrub resume\fP [-Bdqru] {\fI<path>\fP|\fI<device>\fP}
46 \fBbtrfs\fP \fBscrub status\fP [-d] {\fI<path>\fP|\fI<device>\fP}
48 \fBbtrfs\fP \fBinspect-internal inode-resolve\fP [-v] \fI<inode>\fP \fI<path>\fP
50 \fBbtrfs\fP \fBinspect-internal logical-resolve\fP
51 [-Pv] [-s size] \fI<logical>\fP \fI<path>\fP
53 \fBbtrfs\fP \fBhelp|\-\-help|\-h \fP\fI\fP
55 \fBbtrfs\fP \fB<command> \-\-help \fP\fI\fP
59 is used to control the filesystem and the files and directories stored. It is
60 the tool to create or destroy a snapshot or a subvolume for the
61 filesystem, to defrag a file or a directory, flush the data to the disk,
62 to resize the filesystem, to scan the device.
64 It is possible to abbreviate the commands unless the commands are ambiguous.
65 For example: it is possible to run
68 .I btrfs subvolume snapshot.
71 is not allowed, because
73 may be interpreted both as
79 returns filesystem sync
80 If a command is terminated by
82 , the detailed help is showed. If the passed command matches more commands,
83 detailed help of all the matched commands is showed. For example
92 \fBsubvolume snapshot\fR\fI [-r] <source> [<dest>/]<name>\fR
93 Create a writable/readonly snapshot of the subvolume \fI<source>\fR with the
94 name \fI<name>\fR in the \fI<dest>\fR directory. If \fI<source>\fR is not a
95 subvolume, \fBbtrfs\fR returns an error. If \fI-r\fR is given, the snapshot
99 \fBsubvolume delete\fR\fI <subvolume> [<subvolume>...]\fR
100 Delete the subvolume \fI<subvolume>\fR. If \fI<subvolume>\fR is not a
101 subvolume, \fBbtrfs\fR returns an error.
104 \fBsubvolume create\fR\fI [<dest>/]<name>\fR
105 Create a subvolume in \fI<dest>\fR (or in the current directory if
106 \fI<dest>\fR is omitted).
109 \fBsubvolume list\fR\fI [-aprts][-g [+|-]value] [-c [+|-]value] [--sort=gen,ogen,rootid,path] <path>\fR
111 List the subvolumes present in the filesystem \fI<path>\fR. For every
112 subvolume the following information is shown by default.
113 ID <ID> top level <ID> path <path>
114 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.
123 \fB-t\fP print the result as a table.
125 \fB-a\fP print all the subvolumes in the filesystem.
127 \fB-r\fP only readonly subvolumes in the filesystem wille be listed.
129 \fB-s\fP only snapshot subvolumes in the filesystem will be listed.
132 list subvolumes in the filesystem that its generation is
133 >=, <= or = value. '+' means >= value, '-' means <= value, If there is
134 neither '+' nor '-', it means = value.
137 list subvolumes in the filesystem that its ogeneration is
138 >=, <= or = value. The usage is the same to '-g' option.
140 \fB--sort=gen,ogen,path,rootid\fP
141 list subvolumes in order by specified items.
142 you can add '+' or '-' in front of each items, '+' means ascending,'-'
143 means descending. The default is ascending.
145 for \fB--sort\fP you can combine some items together by ',', just like
146 \f--sort=+ogen,-gen,path,rootid\fR.
150 \fBsubvolume set-default\fR\fI <id> <path>\fR
151 Set the subvolume of the filesystem \fI<path>\fR which is mounted as
152 \fIdefault\fR. The subvolume is identified by \fI<id>\fR, which
153 is returned by the \fBsubvolume list\fR command.
156 \fBsubvolume get-default\fR\fI <path>\fR
157 Get the default subvolume of the filesystem \fI<path>\fR. The output format
158 is similar to \fBsubvolume list\fR command.
161 \fBfilesystem defragment\fP -c[zlib|lzo] [-l \fIlen\fR] [-s \fIstart\fR] \
162 [-t \fIsize\fR] -[vf] <\fIfile\fR>|<\fIdir\fR> [<\fIfile\fR>|<\fIdir\fR>...]
164 Defragment file data and/or directory metadata. To defragment all files in a
165 directory you have to specify each one on its own or use your shell wildcards.
167 The start position and the number of bytes to defragment can be specified by
168 \fIstart\fR and \fIlen\fR. Any extent bigger than threshold will be
169 considered already defragged. Use 0 to take the kernel default, and use 1 to
170 say every single extent must be rewritten. You can also turn on compression in
171 defragment operations.
175 \fB-c\fP compress file contents while defragmenting
177 \fB-f\fP flush filesystem after defragmenting
179 \fB-s start\fP defragment only from byte \fIstart\fR onward
181 \fB-l len\fP defragment only up to \fIlen\fR bytes
183 \fB-t size\fP defragment only files at least \fIsize\fR bytes big
185 NOTE: defragmenting with kernels up to 2.6.37 will unlink COW-ed copies of data,
186 don't use it if you use snapshots, have de-duplicated your data or made
187 copies with \fBcp --reflink\fP.
190 \fBsubvolume find-new\fR\fI <subvolume> <last_gen>\fR
191 List the recently modified files in a subvolume, after \fI<last_gen>\fR ID.
194 \fBfilesystem sync\fR\fI <path> \fR
195 Force a sync for the filesystem identified by \fI<path>\fR.
199 .\" Some wording are extracted by the resize2fs man page
202 \fBfilesystem resize\fR\fI [devid:][+/\-]<size>[gkm]|[devid:]max <path>\fR
203 Resize a filesystem identified by \fI<path>\fR for the underlying device
204 \fIdevid\fR. The \fIdevid\fR can be found with \fBbtrfs filesystem show\fR and
205 defaults to 1 if not specified.
206 The \fI<size>\fR parameter specifies the new size of the filesystem.
207 If the prefix \fI+\fR or \fI\-\fR is present the size is increased or decreased
208 by the quantity \fI<size>\fR.
209 If no units are specified, the unit of the \fI<size>\fR parameter defaults to
210 bytes. Optionally, the size parameter may be suffixed by one of the following
211 units designators: 'K', 'M', or 'G', kilobytes, megabytes, or gigabytes,
214 If 'max' is passed, the filesystem will occupy all available space on the
217 The \fBresize\fR command \fBdoes not\fR manipulate the size of underlying
218 partition. If you wish to enlarge/reduce a filesystem, you must make sure you
219 can expand the partition before enlarging the filesystem and shrink the
220 partition after reducing the size of the filesystem. This can done using
221 \fBfdisk(8)\fR or \fBparted(8)\fR to delete the existing partition and recreate
222 it with the new desired size. When recreating the partition make sure to use
223 the same starting disk cylinder as before.
226 \fBfilesystem label\fP\fI <dev> [newlabel]\fP
227 Show or update the label of a filesystem. \fI<dev>\fR is used to identify the
229 If a \fInewlabel\fR optional argument is passed, the label is changed. The
230 following constraints exist for a label:
232 - the maximum allowable length shall be less or equal than 256 chars
234 - the label shall not contain the '/' or '\\' characters.
236 NOTE: Currently there are the following limitations:
238 - the filesystem has to be unmounted
240 - the filesystem should not have more than one device.
243 \fBfilesystem show\fR [--all-devices|<uuid>|<label>]\fR
244 Show the btrfs filesystem with some additional info. If no \fIUUID\fP or
245 \fIlabel\fP is passed, \fBbtrfs\fR show info of all the btrfs filesystem.
246 If \fB--all-devices\fP is passed, all the devices under /dev are scanned;
247 otherwise the devices list is extracted from the /proc/partitions file.
250 \fBfilesystem balance\fR \fI<path>\fR
251 Balance the chunks of the filesystem identified by \fI<path>\fR
255 \fBdevice add\fR\fI <dev> [<dev>..] <path>\fR
256 Add device(s) to the filesystem identified by \fI<path>\fR.
259 \fBdevice delete\fR\fI <dev> [<dev>..] <path>\fR
260 Remove device(s) from a filesystem identified by \fI<path>\fR.
263 \fBdevice scan\fR \fI[--all-devices|<device> [<device>...]\fR
264 If one or more devices are passed, these are scanned for a btrfs filesystem.
265 If no devices are passed, \fBbtrfs\fR scans all the block devices listed
266 in the /proc/partitions file.
267 Finally, if \fB--all-devices\fP is passed, all the devices under /dev are
271 \fBscrub start\fP [-Bdqru] {\fI<path>\fP|\fI<device>\fP}
272 Start a scrub on all devices of the filesystem identified by \fI<path>\fR or on
273 a single \fI<device>\fR. Without options, scrub is started as a background
274 process. Progress can be obtained with the \fBscrub status\fR command. Scrubbing
275 involves reading all data from all disks and verifying checksums. Errors are
276 corrected along the way if possible.
281 Do not background and print scrub statistics when finished.
283 Print separate statistics for each device of the filesystem (-B only).
285 Quiet. Omit error messages and statistics.
287 Read only mode. Do not attempt to correct anything.
289 Scrub unused space as well. (NOT IMPLEMENTED)
293 \fBscrub cancel\fP {\fI<path>\fP|\fI<device>\fP}
294 If a scrub is running on the filesystem identified by \fI<path>\fR, cancel it.
295 Progress is saved in the scrub progress file and scrubbing can be resumed later
296 using the \fBscrub resume\fR command.
297 If a \fI<device>\fR is given, the corresponding filesystem is found and
298 \fBscrub cancel\fP behaves as if it was called on that filesystem.
301 \fBscrub resume\fP [-Bdqru] {\fI<path>\fP|\fI<device>\fP}
302 Resume a canceled or interrupted scrub cycle on the filesystem identified by
303 \fI<path>\fR or on a given \fI<device>\fR. Does not start a new scrub if the
304 last scrub finished successfully.
309 see \fBscrub start\fP.
313 \fBscrub status\fP [-d] {\fI<path>\fP|\fI<device>\fP}
314 Show status of a running scrub for the filesystem identified by \fI<path>\fR or
315 for the specified \fI<device>\fR.
316 If no scrub is running, show statistics of the last finished or canceled scrub
317 for that filesystem or device.
322 Print separate statistics for each device of the filesystem.
326 \fBinspect-internal inode-resolve\fP [-v] \fI<inode>\fP \fI<path>\fP
327 Resolves an <inode> in subvolume <path> to all filesystem paths.
332 verbose mode. print count of returned paths and ioctl() return value
336 \fBinspect-internal logical-resolve\fP [-Pv] [-s bufsize] \fI<logical>\fP \fI<path>\fP
337 Resolves a <logical> address in the filesystem mounted at <path> to all inodes.
338 By default, each inode is then resolved to a file system path (similar to the
339 \fBinode-resolve\fP subcommand).
344 skip the path resolving and print the inodes instead
346 verbose mode. print count of returned paths and all ioctl() return values
348 set inode container's size. This is used to increase inode container's size in case it is
349 not enough to read all the resolved results. The max value one can set is 64k.
353 \fBbtrfs\fR returns a zero exist status if it succeeds. Non zero is returned in
358 is part of btrfs-progs. Btrfs filesystem is currently under heavy development,
359 and not suitable for any uses other than benchmarking and review.
360 Please refer to the btrfs wiki http://btrfs.wiki.kernel.org for