For snapshot shared tree blocks with source subvolume, the keyed backref
counter only counts the exclusive owned references.
In the following case, 258 is a snapshot of 257, which inherits all the
reference to this data extent.
------
item 4 key (12582912 EXTENT_ITEM 524288) itemoff 3741 itemsize 140
refs 179 gen 9 flags DATA
extent data backref root 257 objectid 258 offset 0 count 49
extent data backref root 257 objectid 257 offset 0 count 1
extent data backref root 256 objectid 258 offset 0 count 128
extent data backref root 256 objectid 257 offset 0 count 1
------
However lowmem mode used to iterate the whole inode to find all
references, and doesn't care if a reference is already counted by the
shared tree block.
Add the test case to check it.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The image is dumped by modifying kernel to sleep long enough before
merging relocation trees, so we can just copy the whole image to other
place before kernel begins to merge reloc trees.
And the base image is created by the following script to bump metadata
size:
------
dev=~/test.img
mnt=/mnt/btrfs
umount $mnt &> /dev/null
fallocate -l 128M $dev
mkfs.btrfs -f -n 4k -m single -d single $dev
mount $dev $mnt -o nospace_cache,max_inline=2048
btrfs subvolume create $mnt/src
for i in $(seq -w 0 128); do
xfs_io -f -c "pwrite 0 2k" $mnt/src/file_$i > /dev/null
done
for i in $(seq -w 0 64); do
btrfs subvolume snapshot $mnt/src/ $mnt/snapshot_$i
touch $mnt/snapshot_$i/new
done
sync
------
The image triggers several corner cases that the old lowmem mode didn't
consider.
Like metadata backref with FULL_BACKREF flag and only SHARED_BLOCK_REF
backrefs for metadata. And several tree reloc trees with shared
leaves/nodes to confuse old lowmem mode.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Introduce a new test image, which has an extent item with no inlined
extent data ref, but all keyed extent data ref.
Only in this case we can trigger fase data extent backref lost bug in
lowmem mode.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add a image which can reproduce the extent item referencer count
mismatch false alert for lowmem mode.
Reported-by: Marc MERLIN <marc@merlins.org>
Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add a image that the inlined extent coexist with the regular extent.
Reported-by: Marc MERLIN <marc@merlins.org>
Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Introduce a new image, which contains external SHARED_DATA_REF items to
trigger a lowmem mode false alert.
The image only contains external SHARED_DATA_REF and no inlined data
backref.
Before the image, we only have inlined shared data ref, which is not
enough to trigger lowmem mode false alert.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add a minimal image which can reproduce the block group used space
false alert for lowmem mode fsck.
Reported-by: Christoph Anton Mitterer <calestyo@scientia.net>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In order to confirm that btrfsck supports to check a variety of
refs, add the
following cases:
* keyed_block_ref
* keyed_data_ref
* shared_block_ref
* shared_data_ref
* no_inline_ref (a extent item without inline ref)
* no_skinny_ref
Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Qu Wenruo