On Wed, Sep 07, 2016 at 08:17:38PM +0800, Wang Xiaoguang wrote: > 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.
Could you make this into an xfstest so we can avoid future regressions, please? --D > > 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.f...@cn.fujitsu.com> > --- > fs/btrfs/inode.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > index e6811c4..40f0762 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -9206,6 +9206,7 @@ static int btrfs_truncate(struct inode *inode) > break; > } > > + btrfs_block_rsv_release(root, rsv, -1); > ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, > rsv, min_size, 0); > BUG_ON(ret); /* shouldn't happen */ > -- > 2.9.0 > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
