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btrfs-progs/man/btrfs-image.8.in

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Fix man page headers to include the correct program name.
2009-06-03 16:13:01 +00:00
.TH BTRFS-IMAGE 8
Add btrfs-image man page Signed-off-by: Peng Tao <bergwolf@gmail.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-03 16:00:20 +00:00
.SH NAME
btrfs-image \- create/restore an image of the filesystem
.SH SYNOPSIS
.B btrfs-image
[options] \fIsource\fP \fItarget\fP
.SH DESCRIPTION
.B btrfs-image
is used to create an image of a btrfs filesystem. All data will be zeroed,
but metadata and the like is preserved.
.I source
is the special file corresponding to the device containing a btrfs filesystem.
(e.g \fI/dev/sdXX\fP).
.I target
is the image file that btrfs-image creates. When used with \fB-r\fP option,
\fBbtrfs-image\fP restores the image file from source into target.
.SH OPTIONS
.TP
\fB\-r\fP
restore metadump image.
.TP
\fB\-c\fR \fIvalue\fP
compression level (0 ~ 9).
.TP
\fB\-t\fR \fIvalue\fP
number of threads (1 ~ 32) to be used to process the image dump or restore.
Btrfs-progs: make btrfs-image restore with a valid chunk tree V2 Previously btrfs-image would set a METADUMP flag and would make one big system chunk to cover the entire file system in the super in order to get around the unpleasant business of having to adjust the chunk tree. This meant that you could use the progs stuff on a restored file system, which is great for testing btrfsck and other such things. But we want to be able to run the tree log replay on a file system that is not able to run the tree log replay. So in order to do this we need to fixup the super's chunk array and the chunk tree itself. This is pretty easy since we restore using the logical offsets of the metadata, so we just have to set the chunk items to have 1 stripe and have the stripes point at the primary device and then use the logical offset of the chunk as the physical offset. With this patch I can restore a file system image that had a tree log and mount the file system and have the log be replayed successfully. This patch also gives you the -o option in case you want the old restore way, in the case where we want to make sure the system chunks as they were given to us are correct. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-03-27 20:55:41 +00:00
.TP
\fB\-o\fP
use the old restore method, this does not fixup the chunk tree so the restored
file system will not be able to be mounted.
Btrfs-progs: add an option to btrfs-image to walk the trees When working with a user with a broken file system I noticed I wasn't able to read some of the blocks properly from the restored image. This is because his extent tree was corrupt and was missing references to some of the blocks, which means they weren't copied into the image when he generated it. So add a -w option which will walk all of the trees manually and copy them into the image. This way we can run fsck against a complete file system image and fix any bugs in fsck. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-03-28 14:26:09 +00:00
.TP
Btrfs-image: add the ability to santize file names when making an image We've had a few users who wouldn't (or couldn't) provide us btrfs-images because we maintain the file names when making an image. So introduce a sanitize option. There are two uses, one that is fast and the other that is dog slow. The fast way just generates garbage that's equal in length to the original name. The slow way will try and find a crc32c collision for the file name that is also the same length. Finding a crc32c collision for the file name "btrfs-progs" on my box without CPU crc32c support takes a little more than 3 minutes, and a little less than 2 minutes for my box that has CPU crc32c support, so it's a lengthy and CPU intensive process. The idea is that we use -s for most cases, and then only use -ss when we need the file system tree to be somewhat sane. I could probably do a better job about finding collisions, but I'll have to revist that later. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-03-22 14:52:07 +00:00
\fB\-s\fP
Sanitize the file names when generating the image. One \fB-s\fP means just
generate random garbage, which means that the directory indexes won't match up
since the hashes won't match with the garbage filenames. Using \fB-ss\fP will
calculate a collision for the filename so that the hashes match, and if it
can't calculate a collision then it will just generate garbage. The collision
calculator is very time and CPU intensive so only use it if you are having
problems with your file system tree and need to have it mostly working.
.TP
Btrfs-progs: add an option to btrfs-image to walk the trees When working with a user with a broken file system I noticed I wasn't able to read some of the blocks properly from the restored image. This is because his extent tree was corrupt and was missing references to some of the blocks, which means they weren't copied into the image when he generated it. So add a -w option which will walk all of the trees manually and copy them into the image. This way we can run fsck against a complete file system image and fix any bugs in fsck. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-03-28 14:26:09 +00:00
\fB\-w\fP
Walk all the trees manually and copy any blocks that are referenced. Use this
option if your extent tree is corrupted to make sure that all of the metadata is
captured.
Add btrfs-image man page Signed-off-by: Peng Tao <bergwolf@gmail.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-03 16:00:20 +00:00
.SH AVAILABILITY
.B btrfs-image
is part of btrfs-progs. Btrfs is currently under heavy development,
and not suitable for any uses other than benchmarking and review.
Please refer to the btrfs wiki
http://btrfs.wiki.kernel.org for further details.
.SH SEE ALSO
Removing btrfsctl, btrfs-vol, btrfs-show With the commit 002d021c (committed October 2011) btrfsctl, btrfs-vol, btrfs-show were declared deprecated. The last patches related to these commands are dated December 2010. These tools are replaced by the "btrfs" tool in all the functionality. This commit removes all the related code. Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> Signed-off-by: David Sterba <dsterba@suse.cz>
2012-06-09 05:52:10 +00:00
.BR btrfsck (8), mkfs.btrfs (8)