As for skinny metadata, key.offset stores levels rather than extent length.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
I noticed a slight problem with btrfs-image, since it was building a chunk tree
by setting the physical offset of the stripes to the same as the logical offset
it created this problem where the super block was now mapped into the file
system differently than it was before. This isn't a huge deal except that we
also carry along the free space cache with us, which is setup with the idea that
super at physical X is at logical Y. So this would make the free space checker
in fsck freak out because it would see that the cache says that the super block
is free space, and that the area where it thought the super block was located is
in fact used. In the mount case we'd end up overwriting real metadata with
backup super blocks. So we need to maintain the physical offsets in our
stripes. This is a huge pain because we store the logical bytenrs of all of our
metadata. This patch scans the entire image looking for chunk tree blocks and
builds an in memory chunk tree so we can write logical blocks to their physical
offsets. With this patch we no longer have the problems I described above.
Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
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>
btrfs-image is assuming that every metadata block is the same size. The
super is a special snowflake though. It's 4K even on 64K filesystems.
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
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>
This fixes up the progs to properly deal with skinny metadata. This adds the -x
option to mkfs and btrfstune for enabling the skinny metadata option. This also
makes changes to fsck so it can properly deal with the skinny metadata entries.
Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
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>
A lot of tree log replay bugs are because of strange space cache setups, so make
btrfs-image scrape the free space cache as well so we can better replicate what
a user is seeing if they have a tree log bug or anything related to free space
cache. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Currently btrfs-image doesn't copy the tree logs, which doesn't help me when
we're trying to debug log replay bugs. Since we don't have entries in the
extent root for the blocks we have to walk down all of the trees in order to
copy them. With this patch I can image a file system with a tree log and it
works fine. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
We use BUG_ON() everywhere in btrfs-image. When users are going to use this
command things are pretty dire, so I'd rather have really good error messages so
I know what happened rather than figure out which one of the 20 BUG_ON()'s made
the stupid thing exit early. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
"mdresotre" sounds like it might be French, but most
likely it's a misspelling of mdrestore. Fix it.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Zach Brown <zab@redhat.com>
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
The new back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer by
searching the tree. The shortcoming of the new back ref is that it only works
for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these fuzzy back
references would be O(number_of_snapshots) and quite slow. The solution used
here is to use the fuzzy back references in the common case where a given tree
block is only referenced by one root, and use the full back references when
multiple roots have a reference
This patch adds btrfs image tool. The image tool is
a debugging tool that creates/restores btrfs metadump
image.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Liu Bo