bdev/aio: implement read-only

Support Aio bdev 'readonly' option in RPC call. The read-only flag
can be dumped from the bdev info. Any writes on a read-only aio bdev
will be fail.

Signed-off-by: Yuhua <yuhua@smartx.com>
Change-Id: I939f72479f8953a3678a8df3083ecce0f96844fb
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/14955
Reviewed-by: GangCao <gang.cao@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Aleksey Marchuk <alexeymar@nvidia.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Community-CI: Mellanox Build Bot

module/bdev/aio/bdev_aio.c

@@ -55,6 +55,7 @@ struct file_disk {
 	int			fd;
 	TAILQ_ENTRY(file_disk)  link;
 	bool			block_size_override;
+	bool			readonly;
 };
 
 /* For user space reaping of completions */
@@ -99,11 +100,12 @@ static int
 bdev_aio_open(struct file_disk *disk)
 {
 	int fd;
+	int io_flag = disk->readonly ? O_RDONLY : O_RDWR;
 
-	fd = open(disk->filename, O_RDWR | O_DIRECT);
+	fd = open(disk->filename, io_flag | O_DIRECT);
 	if (fd < 0) {
 		/* Try without O_DIRECT for non-disk files */
-		fd = open(disk->filename, O_RDWR);
+		fd = open(disk->filename, io_flag);
 		if (fd < 0) {
 			SPDK_ERRLOG("open() failed (file:%s), errno %d: %s\n",
 				    disk->filename, errno, spdk_strerror(errno));
@@ -227,7 +229,6 @@ bdev_aio_destruct_cb(void *io_device)
 	if (rc < 0) {
 		SPDK_ERRLOG("bdev_aio_close() failed\n");
 	}
-
 	aio_free_disk(fdisk);
 }
 
@@ -474,15 +475,25 @@ bdev_aio_get_buf_cb(struct spdk_io_channel *ch, struct spdk_bdev_io *bdev_io,
 static int
 _bdev_aio_submit_request(struct spdk_io_channel *ch, struct spdk_bdev_io *bdev_io)
 {
+	struct file_disk *fdisk = (struct file_disk *)bdev_io->bdev->ctxt;
+
 	switch (bdev_io->type) {
 	/* Read and write operations must be performed on buffers aligned to
 	 * bdev->required_alignment. If user specified unaligned buffers,
 	 * get the aligned buffer from the pool by calling spdk_bdev_io_get_buf. */
 	case SPDK_BDEV_IO_TYPE_READ:
-	case SPDK_BDEV_IO_TYPE_WRITE:
 		spdk_bdev_io_get_buf(bdev_io, bdev_aio_get_buf_cb,
 				     bdev_io->u.bdev.num_blocks * bdev_io->bdev->blocklen);
 		return 0;
+	case SPDK_BDEV_IO_TYPE_WRITE:
+		if (fdisk->readonly) {
+			spdk_bdev_io_complete(bdev_io, SPDK_BDEV_IO_STATUS_FAILED);
+		} else {
+			spdk_bdev_io_get_buf(bdev_io, bdev_aio_get_buf_cb,
+					     bdev_io->u.bdev.num_blocks * bdev_io->bdev->blocklen);
+		}
+		return 0;
+
 	case SPDK_BDEV_IO_TYPE_FLUSH:
 		bdev_aio_flush((struct file_disk *)bdev_io->bdev->ctxt,
 			       (struct bdev_aio_task *)bdev_io->driver_ctx);
@@ -567,6 +578,10 @@ bdev_aio_dump_info_json(void *ctx, struct spdk_json_write_ctx *w)
 
 	spdk_json_write_named_string(w, "filename", fdisk->filename);
 
+	spdk_json_write_named_bool(w, "block_size_override", fdisk->block_size_override);
+
+	spdk_json_write_named_bool(w, "readonly", fdisk->readonly);
+
 	spdk_json_write_object_end(w);
 
 	return 0;
@@ -587,6 +602,7 @@ bdev_aio_write_json_config(struct spdk_bdev *bdev, struct spdk_json_write_ctx *w
 		spdk_json_write_named_uint32(w, "block_size", bdev->blocklen);
 	}
 	spdk_json_write_named_string(w, "filename", fdisk->filename);
+	spdk_json_write_named_bool(w, "readonly", fdisk->readonly);
 	spdk_json_write_object_end(w);
 
 	spdk_json_write_object_end(w);
@@ -685,7 +701,7 @@ bdev_aio_group_destroy_cb(void *io_device, void *ctx_buf)
 }
 
 int
-create_aio_bdev(const char *name, const char *filename, uint32_t block_size)
+create_aio_bdev(const char *name, const char *filename, uint32_t block_size, bool readonly)
 {
 	struct file_disk *fdisk;
 	uint32_t detected_block_size;
@@ -697,6 +713,7 @@ create_aio_bdev(const char *name, const char *filename, uint32_t block_size)
 		SPDK_ERRLOG("Unable to allocate enough memory for aio backend\n");
 		return -ENOMEM;
 	}
+	fdisk->readonly = readonly;
 
 	fdisk->filename = strdup(filename);
 	if (!fdisk->filename) {

module/bdev/aio/bdev_aio.h

@@ -11,7 +11,7 @@
 
 typedef void (*delete_aio_bdev_complete)(void *cb_arg, int bdeverrno);
 
-int create_aio_bdev(const char *name, const char *filename, uint32_t block_size);
+int create_aio_bdev(const char *name, const char *filename, uint32_t block_size, bool readonly);
 
 int bdev_aio_rescan(const char *name);
 void bdev_aio_delete(const char *name, delete_aio_bdev_complete cb_fn, void *cb_arg);

module/bdev/aio/bdev_aio_rpc.c

@@ -13,6 +13,7 @@ struct rpc_construct_aio {
 	char *name;
 	char *filename;
 	uint32_t block_size;
+	bool readonly;
 };
 
 struct rpc_construct_aio_ctx {
@@ -32,6 +33,7 @@ static const struct spdk_json_object_decoder rpc_construct_aio_decoders[] = {
 	{"name", offsetof(struct rpc_construct_aio, name), spdk_json_decode_string},
 	{"filename", offsetof(struct rpc_construct_aio, filename), spdk_json_decode_string},
 	{"block_size", offsetof(struct rpc_construct_aio, block_size), spdk_json_decode_uint32, true},
+	{"readonly", offsetof(struct rpc_construct_aio, readonly), spdk_json_decode_bool, true},
 };
 
 static void
@@ -71,7 +73,7 @@ rpc_bdev_aio_create(struct spdk_jsonrpc_request *request,
 	}
 
 	ctx->request = request;
-	rc = create_aio_bdev(ctx->req.name, ctx->req.filename, ctx->req.block_size);
+	rc = create_aio_bdev(ctx->req.name, ctx->req.filename, ctx->req.block_size, ctx->req.readonly);
 	if (rc) {
 		spdk_jsonrpc_send_error_response(request, rc, spdk_strerror(-rc));
 		free_rpc_construct_aio(ctx);

python/spdk/rpc/bdev.py

@@ -370,13 +370,14 @@ def bdev_raid_delete(client, name):
     return client.call('bdev_raid_delete', params)
 
 
-def bdev_aio_create(client, filename, name, block_size=None):
+def bdev_aio_create(client, filename, name, block_size=None, readonly=False):
     """Construct a Linux AIO block device.
 
     Args:
         filename: path to device or file (ex: /dev/sda)
         name: name of block device
         block_size: block size of device (optional; autodetected if omitted)
+        readonly: set aio bdev as read-only
 
     Returns:
         Name of created block device.
@@ -387,6 +388,9 @@ def bdev_aio_create(client, filename, name, block_size=None):
     if block_size:
         params['block_size'] = block_size
 
+    if readonly:
+        params['readonly'] = readonly
+
     return client.call('bdev_aio_create', params)
 
 

scripts/rpc.py

@@ -424,12 +424,14 @@ if __name__ == "__main__":
         print_json(rpc.bdev.bdev_aio_create(args.client,
                                             filename=args.filename,
                                             name=args.name,
-                                            block_size=args.block_size))
+                                            block_size=args.block_size,
+                                            readonly=args.readonly))
 
     p = subparsers.add_parser('bdev_aio_create', help='Add a bdev with aio backend')
     p.add_argument('filename', help='Path to device or file (ex: /dev/sda)')
     p.add_argument('name', help='Block device name')
     p.add_argument('block_size', help='Block size for this bdev', type=int, nargs='?')
+    p.add_argument("-r", "--readonly", action='store_true', help='Set this bdev as read-only')
     p.set_defaults(func=bdev_aio_create)
 
     def bdev_aio_rescan(args):