diff options
author | Wang Xiaoguang | 2016-09-07 20:17:38 +0800 |
---|---|---|
committer | David Sterba | 2017-01-19 18:00:58 +0100 |
commit | 47b5d64691350e116093c9b47b55ca6b9433bc50 (patch) | |
tree | 1882c38d550baab0c3b788f1c7e1df19db8cd7a8 /lib/ubsan.h | |
parent | 0bf70aebf12d8fa0d06967b72ca4b257eb6adf06 (diff) |
btrfs: fix false enospc error when truncating heavily reflinked file
Below test script can reveal this bug:
dd if=/dev/zero of=fs.img bs=$((1024*1024)) count=100
dev=$(losetup --show -f fs.img)
mkdir -p /mnt/mntpoint
mkfs.btrfs -f $dev
mount $dev /mnt/mntpoint
cd /mnt/mntpoint
echo "workdir is: /mnt/mntpoint"
blocksize=$((128 * 1024))
dd if=/dev/zero of=testfile bs=$blocksize count=1
sync
count=$((17*1024*1024*1024/blocksize))
echo "file size is:" $((count*blocksize))
for ((i = 1; i <= $count; i++)); do
dst_offset=$((blocksize * i))
xfs_io -f -c "reflink testfile 0 $dst_offset $blocksize"\
testfile > /dev/null
done
sync
truncate --size 0 testfile
The last truncate operation will fail for ENOSPC reason, but indeed
it should not fail.
In btrfs_truncate(), we use a temporary block_rsv to do truncate
operation. With every btrfs_truncate_inode_items() call, we migrate space
to this block_rsv, but forget to cleanup previous reservation, which
will make this block_rsv's reserved bytes keep growing, and this reserved
space will only be released in the end of btrfs_truncate(), this metadata
leak will impact other's metadata reservation. In this case, it's
"btrfs_start_transaction(root, 2);" fails for enospc error, which make
this truncate operation fail.
Call btrfs_block_rsv_release() to fix this bug.
Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'lib/ubsan.h')
0 files changed, 0 insertions, 0 deletions