btrfs: make sure EXTENT_BUFFER_READING is cleared under refs_lock

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "fs/btrfs/disk-io.c",
                        "fs/btrfs/extent_io.c"
                    ],
                    "versions": [
                        {
                            "version": "f5427cab065641a4553d38bb8c4932b8d456c7a7",
                            "lessThan": "8f7285d608ed0db7c9f09f341547db5ce1351090",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "83f7e52b7ed1c3e03b79123e20b6f6adf8d886bb",
                            "lessThan": "2073f3d97b0c5d34fe64812d1237e37bd79c17ec",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "83f7e52b7ed1c3e03b79123e20b6f6adf8d886bb",
                            "lessThan": "690c2accacb1aca91ab8186d15dee56da8723f31",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "b0c33c0628c5b0678fcae2e05e7b2764149248f8",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "7.1.8",
                            "lessThan": "7.2",
                            "status": "affected",
                            "versionType": "semver"
                        }
                    ]
                }

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "fs/btrfs/disk-io.c",
                        "fs/btrfs/extent_io.c"
                    ],
                    "versions": [
                        {
                            "version": "7.2",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "7.2",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2.6",
                            "lessThanOrEqual": "7.2.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.3",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }