This also includes a new --repair btrfsck option. For now it can
only fix errors in the extent allocation tree.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
When building on ppc64 I hit a number of warnings in printf:
btrfs-map-logical.c:69: error: format ‘%Lu’ expects type ‘long long
unsigned int’, but argument 4 has type ‘u64’
Fix them.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Hugo Mills <hugo@carfax.org.uk>
gcc-4.6 (as shipped in Fedora) turns on -Wunused-but-set-variable by
default, which breaks the build when combined with -Wall, e.g.:
debug-tree.c: In function ‘print_extent_leaf’:
debug-tree.c:45:13: error: variable ‘last_len’ set but not used [-Werror=unused-but-set-variable]
debug-tree.c:44:13: error: variable ‘last’ set but not used [-Werror=unused-but-set-variable]
debug-tree.c:41:21: error: variable ‘item’ set but not used [-Werror=unused-but-set-variable]
cc1: all warnings being treated as errors
This patch fixes the errors by removing the unused variables.
Signed-off-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Hugo Mills <hugo@carfax.org.uk>
Otherwise we print FIRST_CHUNK_TREE for any objectid 256, which e.g. for
the root tree is the first snap/subvol.
Signed-off-by: Sage Weil <sage@newdream.net>
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
There are still some warnings of the form:
format '%llu' expects type 'long long unsigned int' but argument has type 'u64'
In conjunction with -Werror, this is causing some build failures.
Now they're properly casted, avoiding compiler warnings.
Signed-off-by: Luca Bruno <lucab@debian.org>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
output objectid in btrfs_disk_key with human readable strings.
Other updates are included for more readable output.
Thanks Fengguang's fix to this patch.
Signed-off-by: Shen Feng <shen@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Btrfs stores checksums for each data block. Until now, they have
been stored in the subvolume trees, indexed by the inode that is
referencing the data block. This means that when we read the inode,
we've probably read in at least some checksums as well.
But, this has a few problems:
* The checksums are indexed by logical offset in the file. When
compression is on, this means we have to do the expensive checksumming
on the uncompressed data. It would be faster if we could checksum
the compressed data instead.
* If we implement encryption, we'll be checksumming the plain text and
storing that on disk. This is significantly less secure.
* For either compression or encryption, we have to get the plain text
back before we can verify the checksum as correct. This makes the raid
layer balancing and extent moving much more expensive.
* It makes the front end caching code more complex, as we have touch
the subvolume and inodes as we cache extents.
* There is potentitally one copy of the checksum in each subvolume
referencing an extent.
The solution used here is to store the extent checksums in a dedicated
tree. This allows us to index the checksums by phyiscal extent
start and length. It means:
* The checksum is against the data stored on disk, after any compression
or encryption is done.
* The checksum is stored in a central location, and can be verified without
following back references, or reading inodes.
This makes compression significantly faster by reducing the amount of
data that needs to be checksummed. It will also allow much faster
raid management code in general.
The checksums are indexed by a key with a fixed objectid (a magic value
in ctree.h) and offset set to the starting byte of the extent. This
allows us to copy the checksum items into the fsync log tree directly (or
any other tree), without having to invent a second format for them.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
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>
The offset field in struct btrfs_extent_ref records the position
inside file that file extent is referenced by. In the new back
reference system, tree leaves holding reference to file extent
are recorded explicitly. We can quickly scan these tree leaves, so the
offset field is not required.
This patch also makes the back reference system check the objectid
when extents are being deleted
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
This patch makes the back reference system to explicit record the
location of parent node for all types of extents. The location of
parent node is placed into the offset field of backref key. Every
time a tree block is balanced, the back references for the affected
lower level extents are updated.
Block headers now store the chunk tree uuid
Chunk items records the device uuid for each stripes
Device extent items record better back refs to the chunk tree
Block groups record better back refs to the chunk tree
The chunk tree format has also changed. The objectid of BTRFS_CHUNK_ITEM_KEY
used to be the logical offset of the chunk. Now it is a chunk tree id,
with the logical offset being stored in the offset field of the key.
This allows a single chunk tree to record multiple logical address spaces,
upping the number of bytes indexed by a chunk tree from 2^64 to
2^128.
