{"id":1307003,"url":"http://patchwork.ozlabs.org/api/patches/1307003/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/812b66824859bee38019fc4d35bda0985b13789f.1591801197.git.berto@igalia.com/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":"","list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<812b66824859bee38019fc4d35bda0985b13789f.1591801197.git.berto@igalia.com>","list_archive_url":null,"date":"2020-06-10T15:02:53","name":"[v8,15/34] qcow2: Add qcow2_get_subcluster_range_type()","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"e24505b3b952c69342ce6b365995dcc7e8172bac","submitter":{"id":65704,"url":"http://patchwork.ozlabs.org/api/people/65704/?format=json","name":"Alberto Garcia","email":"berto@igalia.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/812b66824859bee38019fc4d35bda0985b13789f.1591801197.git.berto@igalia.com/mbox/","series":[{"id":182563,"url":"http://patchwork.ozlabs.org/api/series/182563/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=182563","date":"2020-06-10T15:02:49","name":"Add subcluster allocation to qcow2","version":8,"mbox":"http://patchwork.ozlabs.org/series/182563/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/1307003/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/1307003/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@bilbo.ozlabs.org","Authentication-Results":["ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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envelope-from=berto@igalia.com;\n helo=fanzine.igalia.com","X-detected-operating-system":"by eggs.gnu.org: First seen = 2020/06/10 11:03:39","X-ACL-Warn":"Detected OS = Linux 2.2.x-3.x (no timestamps) [generic] [fuzzy]","X-Spam_score_int":"-20","X-Spam_score":"-2.1","X-Spam_bar":"--","X-Spam_report":"(-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001,\n SPF_PASS=-0.001 autolearn=_AUTOLEARN","X-Spam_action":"no action","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.23","Precedence":"list","List-Id":"","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Cc":"Kevin Wolf ,\n Vladimir Sementsov-Ogievskiy ,\n Alberto Garcia , qemu-block@nongnu.org,\n Derek Su , Max Reitz ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"\"Qemu-devel\"\n "},"content":"There are situations in which we want to know how many contiguous\nsubclusters of the same type there are in a given cluster. This can be\ndone by simply iterating over the subclusters and repeatedly calling\nqcow2_get_subcluster_type() for each one of them.\n\nHowever once we determined the type of a subcluster we can check the\nrest efficiently by counting the number of adjacent ones (or zeroes)\nin the bitmap. This is what this function does.\n\nSigned-off-by: Alberto Garcia \nReviewed-by: Eric Blake \n---\n block/qcow2-cluster.c | 51 +++++++++++++++++++++++++++++++++++++++++++\n 1 file changed, 51 insertions(+)","diff":"diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c\nindex 8b2fc550b7..32dc6e75e3 100644\n--- a/block/qcow2-cluster.c\n+++ b/block/qcow2-cluster.c\n@@ -375,6 +375,57 @@ fail:\n return ret;\n }\n \n+/*\n+ * For a given L2 entry, count the number of contiguous subclusters of\n+ * the same type starting from @sc_from. Compressed clusters are\n+ * treated as if they were divided into subclusters of size\n+ * s->subcluster_size.\n+ *\n+ * Return the number of contiguous subclusters and set @type to the\n+ * subcluster type.\n+ *\n+ * If the L2 entry is invalid return -errno and set @type to\n+ * QCOW2_SUBCLUSTER_INVALID.\n+ */\n+G_GNUC_UNUSED\n+static int qcow2_get_subcluster_range_type(BlockDriverState *bs,\n+ uint64_t l2_entry,\n+ uint64_t l2_bitmap,\n+ unsigned sc_from,\n+ QCow2SubclusterType *type)\n+{\n+ BDRVQcow2State *s = bs->opaque;\n+ uint32_t val;\n+\n+ *type = qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, sc_from);\n+\n+ if (*type == QCOW2_SUBCLUSTER_INVALID) {\n+ return -EINVAL;\n+ } else if (!has_subclusters(s) || *type == QCOW2_SUBCLUSTER_COMPRESSED) {\n+ return s->subclusters_per_cluster - sc_from;\n+ }\n+\n+ switch (*type) {\n+ case QCOW2_SUBCLUSTER_NORMAL:\n+ val = l2_bitmap | QCOW_OFLAG_SUB_ALLOC_RANGE(0, sc_from);\n+ return cto32(val) - sc_from;\n+\n+ case QCOW2_SUBCLUSTER_ZERO_PLAIN:\n+ case QCOW2_SUBCLUSTER_ZERO_ALLOC:\n+ val = (l2_bitmap | QCOW_OFLAG_SUB_ZERO_RANGE(0, sc_from)) >> 32;\n+ return cto32(val) - sc_from;\n+\n+ case QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN:\n+ case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC:\n+ val = ((l2_bitmap >> 32) | l2_bitmap)\n+ & ~QCOW_OFLAG_SUB_ALLOC_RANGE(0, sc_from);\n+ return ctz32(val) - sc_from;\n+\n+ default:\n+ g_assert_not_reached();\n+ }\n+}\n+\n /*\n * Checks how many clusters in a given L2 slice are contiguous in the image\n * file. As soon as one of the flags in the bitmask stop_flags changes compared\n","prefixes":["v8","15/34"]}