Merge pull request #223 from mariuszbarczak/introducing-new-io-class-caching-rule-file-name-prefix

Introducing a new IO class caching rule - file name prefix

modules/cas_cache/classifier.c

@@ -190,14 +190,21 @@ error:
 static int _cas_cls_string_ctr(struct cas_classifier *cls,
 		struct cas_cls_condition *c, char *data)
 {
+	size_t len;
 	struct cas_cls_string *ctx;
 
-	if (!data || strlen(data) == 0) {
+	if (!data) {
 		CAS_CLS_MSG(KERN_ERR, "Missing string specifier\n");
 		return -EINVAL;
 	}
 
-	if (strlen(data) > MAX_STRING_SPECIFIER_LEN) {
+	len = strlen(data);
+	if (len == 0) {
+		CAS_CLS_MSG(KERN_ERR, "String specifier is empty\n");
+		return -EINVAL;
+	}
+
+	if (len > MAX_STRING_SPECIFIER_LEN) {
 		CAS_CLS_MSG(KERN_ERR, "String specifier to long: %s\n", data);
 		return -EINVAL;
 	}
@@ -207,6 +214,7 @@ static int _cas_cls_string_ctr(struct cas_classifier *cls,
 		return -ENOMEM;
 
 	strcpy(ctx->string, data);
+	ctx->len = len;
 
 	c->context = ctx;
 
@@ -477,6 +485,41 @@ static cas_cls_eval_t _cas_cls_extension_test(
 	return cas_cls_eval_no;
 }
 
+/* File name prefix test function */
+static cas_cls_eval_t _cas_cls_file_name_prefix_test(
+		struct cas_classifier *cls, struct cas_cls_condition *c,
+		struct cas_cls_io *io, ocf_part_id_t part_id)
+{
+	struct cas_cls_string *ctx;
+	struct inode *inode;
+	struct dentry *dentry;
+	uint32_t len;
+
+	ctx = c->context;
+	inode = io->inode;
+
+	if (!inode)
+		return cas_cls_eval_no;
+
+	/* I/O target inode dentry */
+	dentry = _cas_cls_dir_get_inode_dentry(inode);
+
+	/* Check if dentry and its name is valid */
+	if (!dentry || !dentry->d_name.name)
+		return cas_cls_eval_no;
+
+	/* Check if name is not too short, we expect full prefix in name */
+	if (dentry->d_name.len < ctx->len)
+		return cas_cls_eval_no;
+
+	/* Final string comparison check */
+	len = min(ctx->len, dentry->d_name.len);
+	if (strncmp(dentry->d_name.name, ctx->string, len) == 0)
+		return cas_cls_eval_yes;
+
+	return cas_cls_eval_no;
+}
+
 /* LBA test function */
 static cas_cls_eval_t _cas_cls_lba_test(
 		struct cas_classifier *cls, struct cas_cls_condition *c,
@@ -566,6 +609,8 @@ static struct cas_cls_condition_handler _handlers[] = {
 			_cas_cls_directory_dtr },
 	{ "extension", _cas_cls_extension_test, _cas_cls_string_ctr,
 			_cas_cls_generic_dtr },
+	{ "file_name_prefix", _cas_cls_file_name_prefix_test, _cas_cls_string_ctr,
+			_cas_cls_generic_dtr },
 	{ "lba", _cas_cls_lba_test, _cas_cls_numeric_ctr, _cas_cls_generic_dtr },
 	{ "pid", _cas_cls_pid_test, _cas_cls_numeric_ctr, _cas_cls_generic_dtr },
 	{ "process_name", _cas_cls_process_name_test, _cas_cls_string_ctr,

modules/cas_cache/classifier_defs.h

@@ -124,6 +124,9 @@ struct cas_cls_numeric {
 struct cas_cls_string {
 	/* String specifier*/
 	char string[MAX_STRING_SPECIFIER_LEN];
+
+	/* String length */
+	uint32_t len;
 };
 
 /* Directory condition context */

test/functional/api/cas/ioclass_config.py

@@ -99,8 +99,9 @@ class IoClass:
         return random_list
 
     def set_random_rule(self):
-        rules = ["metadata", "direct", "file_size", "directory", "io_class", "extension", "lba",
-                 "pid", "process_name", "file_offset", "request_size"]
+        rules = ["metadata", "direct", "file_size", "directory", "io_class",
+                 "extension", "file_name_prefix", "lba", "pid", "process_name",
+                 "file_offset", "request_size"]
         if os_utils.get_kernel_version() >= version.Version("4.13"):
             rules.append("wlth")
 
@@ -117,7 +118,7 @@ class IoClass:
             rule += f":{Operator(random.randrange(len(Operator))).name}:{random.randrange(1000000)}"
         elif rule == "io_class":
             rule += f":{random.randrange(MAX_IO_CLASS_PRIORITY + 1)}"
-        elif rule in ["extension", "process_name"]:
+        elif rule in ["extension", "process_name", "file_name_prefix"]:
             rule += f":{random_string(random.randint(1, 10))}"
         if random.randrange(2):
             rule += "&done"

test/functional/tests/io_class/test_io_class_file.py

@@ -77,6 +77,84 @@ def test_ioclass_file_extension():
         assert stats["dirty"].get_value(Unit.Blocks4096) == 0
 
 
+@pytest.mark.require_disk("cache", DiskTypeSet([DiskType.optane, DiskType.nand]))
+@pytest.mark.require_disk("core", DiskTypeLowerThan("cache"))
+def test_ioclass_file_name_prefix():
+    cache, core = prepare()
+    ioclass_id = 1
+    cached_files = ["test", "test.txt", "test1", "test1.txt"]
+    not_cached_files = ["file1", "file2", "file4", "file5", "tes"]
+    dd_size = Size(4, Unit.KibiByte)
+    dd_count = 10
+
+    ioclass_config.remove_ioclass_config()
+    ioclass_config.create_ioclass_config(False)
+
+    # Avoid caching anything else than files with specified prefix
+    ioclass_config.add_ioclass(
+        ioclass_id=0,
+        eviction_priority=255,
+        allocation=False,
+        rule=f"unclassified",
+        ioclass_config_path=ioclass_config_path,
+    )
+    # Enables file with specified prefix to be cached
+    ioclass_config.add_ioclass(
+        ioclass_id=ioclass_id,
+        eviction_priority=1,
+        allocation=True,
+        rule=f"file_name_prefix:test&done",
+        ioclass_config_path=ioclass_config_path,
+    )
+    casadm.load_io_classes(cache_id=cache.cache_id, file=ioclass_config_path)
+
+    TestRun.LOGGER.info(
+        f"Preparing filesystem and mounting {core.system_path} at {mountpoint}"
+    )
+
+    previous_occupancy = cache.get_occupancy()
+
+    core.create_filesystem(Filesystem.ext3)
+    core.mount(mountpoint)
+
+    assert previous_occupancy.get_value() <= cache.get_occupancy().get_value()
+
+    # Filesystem creation caused metadata IO which is not supposed
+    # to be cached
+
+    # Check if files with proper prefix are cached
+    TestRun.LOGGER.info(f"Writing files which are supposed to be cached.")
+    for f in cached_files:
+        dd = (
+            Dd()
+            .input("/dev/zero")
+            .output(f"{mountpoint}/{f}")
+            .count(dd_count)
+            .block_size(dd_size)
+        )
+        dd.run()
+        sync()
+        current_occupancy = cache.get_occupancy()
+        assert current_occupancy == previous_occupancy
+        previous_occupancy = current_occupancy
+
+    cache.flush_cache()
+
+    # Check if file with improper extension is not cached
+    TestRun.LOGGER.info(f"Writing files which are not supposed to be cached.")
+    for f in not_cached_files:
+        dd = (
+            Dd()
+            .input("/dev/zero")
+            .output(f"{mountpoint}/{f}")
+            .count(dd_count)
+            .block_size(dd_size)
+        )
+        dd.run()
+        sync()
+        current_occupancy = cache.get_occupancy()
+        assert current_occupancy != previous_occupancy
+
 @pytest.mark.require_disk("cache", DiskTypeSet([DiskType.optane, DiskType.nand]))
 @pytest.mark.require_disk("core", DiskTypeLowerThan("cache"))
 def test_ioclass_file_extension_preexisting_filesystem():