f2fs: fix to account compressed blocks in f2fs_compressed_blocks()

por_fsstress reports inconsistent status in orphan inode, the root cause
of this is in f2fs_write_raw_pages() we decrease i_compr_blocks incorrectly
due to wrong calculation in f2fs_compressed_blocks().

So this patch exposes below two functions based on __f2fs_cluster_blocks:
- f2fs_compressed_blocks: get count of compressed blocks in compressed cluster
- f2fs_cluster_blocks: get count of valid blocks (including reserved blocks)
in compressed cluster.

Then use f2fs_compress_blocks() to get correct compressed blocks count in
f2fs_write_raw_pages().

sanity_check_inode: inode (ino=ad80) hash inconsistent i_compr_blocks:2, i_blocks:1, run fsck to fix
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/compress.c

@@ -535,8 +535,7 @@ static bool __cluster_may_compress(struct compress_ctx *cc)
 	return true;
 }
 
-/* return # of compressed block addresses */
-static int f2fs_compressed_blocks(struct compress_ctx *cc)
+static int __f2fs_cluster_blocks(struct compress_ctx *cc, bool compr)
 {
 	struct dnode_of_data dn;
 	int ret;
@@ -559,8 +558,13 @@ static int f2fs_compressed_blocks(struct compress_ctx *cc)
 
 			blkaddr = data_blkaddr(dn.inode,
 					dn.node_page, dn.ofs_in_node + i);
-			if (blkaddr != NULL_ADDR)
-				ret++;
+			if (compr) {
+				if (__is_valid_data_blkaddr(blkaddr))
+					ret++;
+			} else {
+				if (blkaddr != NULL_ADDR)
+					ret++;
+			}
 		}
 	}
 fail:
@@ -568,6 +572,18 @@ static int f2fs_compressed_blocks(struct compress_ctx *cc)
 	return ret;
 }
 
+/* return # of compressed blocks in compressed cluster */
+static int f2fs_compressed_blocks(struct compress_ctx *cc)
+{
+	return __f2fs_cluster_blocks(cc, true);
+}
+
+/* return # of valid blocks in compressed cluster */
+static int f2fs_cluster_blocks(struct compress_ctx *cc, bool compr)
+{
+	return __f2fs_cluster_blocks(cc, false);
+}
+
 int f2fs_is_compressed_cluster(struct inode *inode, pgoff_t index)
 {
 	struct compress_ctx cc = {
@@ -577,7 +593,7 @@ int f2fs_is_compressed_cluster(struct inode *inode, pgoff_t index)
 		.cluster_idx = index >> F2FS_I(inode)->i_log_cluster_size,
 	};
 
-	return f2fs_compressed_blocks(&cc);
+	return f2fs_cluster_blocks(&cc, false);
 }
 
 static bool cluster_may_compress(struct compress_ctx *cc)
@@ -626,7 +642,7 @@ static int prepare_compress_overwrite(struct compress_ctx *cc,
 	bool prealloc;
 
 retry:
-	ret = f2fs_compressed_blocks(cc);
+	ret = f2fs_cluster_blocks(cc, false);
 	if (ret <= 0)
 		return ret;