[PATCH v3] f2fs_io: add dev_alias command for dynamic device aliasing management

[Daeho Jeong <daeho43@gmail.com>]

From: Daeho Jeong <daehojeong@google.com>

This commit adds a new 'dev_alias' command to f2fs_io tool to support
dynamic release, reservation and status querying of device alias ranges.

Signed-off-by: Daeho Jeong <daehojeong@google.com>

---
v3: renamed the interfaces for dev_alias.
v2: remove a f2fs specific flag from getflags.
---
 tools/f2fs_io/f2fs_io.c | 46 +++++++++++++++++++++++++++++++++++++++++
 tools/f2fs_io/f2fs_io.h |  7 +++++++
 2 files changed, 53 insertions(+)

diff --git a/tools/f2fs_io/f2fs_io.c b/tools/f2fs_io/f2fs_io.c
index c977f4d..1a219b8 100644
--- a/tools/f2fs_io/f2fs_io.c
+++ b/tools/f2fs_io/f2fs_io.c
@@ -2509,6 +2509,51 @@ static void do_test_lookup_perf(int argc, char **argv, const struct cmd_desc *cm
 	exit(0);
 }
 
+#define dev_alias_desc "device alias control"
+#define dev_alias_help						\
+"f2fs_io dev_alias [release|reserve|status] [file]\n\n"			\
+"release, reserve or status a range of device alias given the file\n"
+
+static void do_dev_alias(int argc, char **argv, const struct cmd_desc *cmd)
+{
+	int fd, ret;
+
+	if (argc != 3) {
+		fputs("Excess arguments\n\n", stderr);
+		fputs(cmd->cmd_help, stderr);
+		exit(1);
+	}
+
+	fd = xopen(argv[2], O_RDWR, 0);
+
+	if (!strcmp(argv[1], "reserve")) {
+		ret = ioctl(fd, F2FS_IOC_RESERVE_DEV_ALIAS);
+		if (ret < 0)
+			die_errno("F2FS_IOC_RESERVE_DEV_ALIAS failed");
+		printf("%s device alias range of %s\n", argv[1], argv[2]);
+	} else if (!strcmp(argv[1], "release")) {
+		ret = ioctl(fd, F2FS_IOC_RELEASE_DEV_ALIAS);
+		if (ret < 0)
+			die_errno("F2FS_IOC_RELEASE_DEV_ALIAS failed");
+		printf("%s device alias range of %s\n", argv[1], argv[2]);
+	} else if (!strcmp(argv[1], "status")) {
+		u32 status = 0;
+
+		ret = ioctl(fd, F2FS_IOC_GET_DEV_ALIAS_STATUS, &status);
+		if (ret < 0)
+			die_errno("F2FS_IOC_GET_DEV_ALIAS_STATUS failed");
+
+		printf("device alias status of %s: %s\n", argv[2],
+			status == F2FS_DEV_ALIAS_STATUS_RESERVED ? "reserved" : "released");
+	} else {
+		fputs("Wrong request type\n\n", stderr);
+		fputs(cmd->cmd_help, stderr);
+		exit(1);
+	}
+
+	exit(0);
+}
+
 #define freeze_desc "freeze filesystem"
 #define freeze_help "f2fs_io freeze [directory_path]\n\n"
 
@@ -2603,6 +2648,7 @@ const struct cmd_desc cmd_list[] = {
 	CMD(get_advise),
 	CMD(ioprio),
 	CMD(ftruncate),
+	CMD(dev_alias),
 	CMD(test_create_perf),
 	CMD(test_lookup_perf),
 	CMD(freeze),
diff --git a/tools/f2fs_io/f2fs_io.h b/tools/f2fs_io/f2fs_io.h
index b0d4099..41387f2 100644
--- a/tools/f2fs_io/f2fs_io.h
+++ b/tools/f2fs_io/f2fs_io.h
@@ -96,6 +96,9 @@ typedef u32	__be32;
 #define F2FS_IOC_START_ATOMIC_REPLACE	_IO(F2FS_IOCTL_MAGIC, 25)
 #define F2FS_IOC_GET_DEV_ALIAS_FILE	_IOR(F2FS_IOCTL_MAGIC, 26, __u32)
 #define F2FS_IOC_IO_PRIO		_IOW(F2FS_IOCTL_MAGIC, 27, __u32)
+#define F2FS_IOC_RESERVE_DEV_ALIAS	_IO(F2FS_IOCTL_MAGIC, 28)
+#define F2FS_IOC_RELEASE_DEV_ALIAS	_IO(F2FS_IOCTL_MAGIC, 29)
+#define F2FS_IOC_GET_DEV_ALIAS_STATUS	_IOR(F2FS_IOCTL_MAGIC, 30, __u32)
 
 #ifndef FSCRYPT_POLICY_V1
 #define FSCRYPT_POLICY_V1		0
@@ -200,6 +203,10 @@ enum {
 	F2FS_IOPRIO_WRITE = 1,  /* high write priority */
 };
 
+/* for F2FS_IOC_GET_DEV_ALIAS_STATUS */
+#define F2FS_DEV_ALIAS_STATUS_RELEASED	0
+#define F2FS_DEV_ALIAS_STATUS_RESERVED	1
+
 #ifndef FS_IMMUTABLE_FL
 #define FS_IMMUTABLE_FL			0x00000010 /* Immutable file */
 #endif
-- 
2.55.0.571.g244d577d93-goog