vdev/geom: Add vdev chr/blk devices access support

Add to ZFS ability to open char/block devices, which does not have the
geom provider. The functionality is implemented under vdev_file, which
now able to open char and block devices from devfs additionally to
regular files.

The geom provider detection decision is made under platform-dependent
zfs_dev_is_whole_disk() function. The two new *strategy* functions are
added to vdev_file platform-dependent API to call devfs device strategy
routine directly. Also, the zfs_file_attr_t structure is modified to
able to get logical and physical devfs device block sizes.

The user logic for devfs devices is the same as for zpool
creation/importing for regular files. Mean, zpool could be created
based on devfs devices and later could be imported by using '-s' option
or using '-d' option with /dev directory argument. In case of zpool
import without arguments, zpool on devfs will not be seen. For devices,
which have both devfs device and geom provider
(case nvme: ndaX/nvdX + nvmeXnsY), pool could be created on geom and
later imported as devfs using vdev_file importing rules and
vise versa.

Signed-off-by: Fedor Uporov <[email protected]>

Author: fuporovvStack

cmd/zpool/zpool_vdev.c

@@ -353,15 +353,32 @@ make_leaf_vdev(nvlist_t *props, const char *arg, boolean_t is_primary)
 		/*
 		 * Determine whether this is a device or a file.
 		 */
+#if defined(__FreeBSD__)
+		if (wholedisk) {
+			/* Devices with geom provider only */
+			type = VDEV_TYPE_DISK;
+		} else if (S_ISREG(statbuf.st_mode) ||
+		    S_ISCHR(statbuf.st_mode) || S_ISBLK(statbuf.st_mode)) {
+			/*
+			 * Regular and devfs files, excluding have geom
+			 * providers. The decision, is it geom provider,
+			 * is made by zfs_dev_is_whole_disk() function.
+			 */
+			type = VDEV_TYPE_FILE;
+		}
+#else
 		if (wholedisk || S_ISBLK(statbuf.st_mode)) {
 			type = VDEV_TYPE_DISK;
 		} else if (S_ISREG(statbuf.st_mode)) {
 			type = VDEV_TYPE_FILE;
-		} else {
-			fprintf(stderr, gettext("cannot use '%s': must "
-			    "be a block device or regular file\n"), path);
-			return (NULL);
 		}
+#endif
+	}
+
+	if (type == NULL) {
+		fprintf(stderr, gettext("cannot use '%s': must "
+		    "be a block device or regular file\n"), path);
+		return (NULL);
 	}
 
 	/*

include/sys/zfs_file.h

@@ -37,8 +37,10 @@ typedef struct file zfs_file_t;
 #endif
 
 typedef struct zfs_file_attr {
-	uint64_t	zfa_size;	/* file size */
-	mode_t		zfa_mode;	/* file type */
+	uint64_t	zfa_size;			/* file size */
+	mode_t		zfa_mode;			/* file type */
+	uint32_t	zfa_logical_block_size;		/* file logical bs */
+	uint32_t	zfa_physical_block_size;	/* file physical bs */
 } zfs_file_attr_t;
 
 int zfs_file_open(const char *path, int flags, int mode, zfs_file_t **fp);
@@ -51,6 +53,9 @@ int zfs_file_read(zfs_file_t *fp, void *buf, size_t len, ssize_t *resid);
 int zfs_file_pread(zfs_file_t *fp, void *buf, size_t len, loff_t off,
     ssize_t *resid);
 
+void zfs_file_io_strategy(zfs_file_t *fp, void *arg);
+void zfs_file_io_strategy_done(zfs_file_t *fp, void *arg);
+
 int zfs_file_seek(zfs_file_t *fp, loff_t *offp, int whence);
 int zfs_file_getattr(zfs_file_t *fp, zfs_file_attr_t *zfattr);
 int zfs_file_fsync(zfs_file_t *fp, int flags);

lib/libzpool/kernel.c

@@ -1324,6 +1324,36 @@ zfs_file_seek(zfs_file_t *fp, loff_t *offp, int whence)
 	return (0);
 }
 
+/*
+ * The file IO strategy routine.
+ *
+ * fp -  pointer to file (regular, blk or chr)
+ * arg - data to transfer from/to file, typically ZFS zio
+ *
+ * Used only on FreeBSD kernel side for now.
+ */
+void
+zfs_file_io_strategy(zfs_file_t *fp, void *arg)
+{
+	(void) fp;
+	(void) arg;
+}
+
+/*
+ * The file IO strategy completion routine.
+ *
+ * fp -  pointer to file (regular, blk or chr)
+ * arg - data to transfer from/to file, typically ZFS zio
+ *
+ * Used only on FreeBSD kernel side for now.
+ */
+void
+zfs_file_io_strategy_done(zfs_file_t *fp, void *arg)
+{
+	(void) fp;
+	(void) arg;
+}
+
 /*
  * Get file attributes
  *
@@ -1344,6 +1374,8 @@ zfs_file_getattr(zfs_file_t *fp, zfs_file_attr_t *zfattr)
 
 	zfattr->zfa_size = st.st_size;
 	zfattr->zfa_mode = st.st_mode;
+	zfattr->zfa_logical_block_size = 0;
+	zfattr->zfa_physical_block_size = 0;
 
 	return (0);
 }

lib/libzutil/os/freebsd/zutil_device_path_os.c

@@ -79,14 +79,23 @@ zfs_get_underlying_path(const char *dev_name)
 boolean_t
 zfs_dev_is_whole_disk(const char *dev_name)
 {
+	boolean_t wholedisk = B_FALSE;
+	char *name;
 	int fd;
 
 	fd = g_open(dev_name, 0);
-	if (fd >= 0) {
-		g_close(fd);
-		return (B_TRUE);
+	if (fd < 0) {
+		return (B_FALSE);
 	}
-	return (B_FALSE);
+
+	name = g_providername(fd);
+	if (name != NULL) {
+		wholedisk = B_TRUE;
+	}
+
+	g_close(fd);
+
+	return (wholedisk);
 }
 
 /*