fs: Provide information about non-block filesystems

The existing disk and partition code assumes a block device.

Sandbox provides access to host files and does not operate through a
block device. This is currently handled with special-case logic.

We want to add virtio-fs support, which is also not a block device. It
is not easy to have these two co-exist, so add a new type field to
struct disk_partition to indicate the type.

This is a work-around to deal with the fact that the type needs to be
set by blk_get_device_part_str() in such a way that it is visible to
fs_readdir()

There is a global fs_type in disk/part.c but this is not available in
the fs/ code.

Signed-off-by: Simon Glass <sjg@chromium.org>

disk/part.c

@@ -477,7 +477,8 @@ int blk_get_device_part_str(const char *ifname, const char *dev_part_str,
 	if (!strcmp(ifname, "hostfs")) {
 		strcpy((char *)info->type, BOOT_PART_TYPE);
 		strcpy((char *)info->name, "Host filesystem");
-
+		info->fs_type = IS_ENABLED(CONFIG_SANDBOX) ? FS_TYPE_SANDBOX :
+			FS_TYPE_SEMIHOSTING;
 		return 0;
 	}
 #endif

fs/fs_legacy.c

@@ -483,7 +483,11 @@ int fs_set_blk_dev(const char *ifname, const char *dev_part_str, int fstype)
 
 		if (!fs_dev_desc && !info->null_dev_desc_ok)
 			continue;
+		if (fs_partition.fs_type &&
+		    fs_partition.fs_type != info->fstype)
+			continue;
 
+		log_debug("probe %s\n", info->name);
 		if (!info->probe(fs_dev_desc, &fs_partition)) {
 			fs_type = info->fstype;
 			fs_dev_part = part;

include/part.h

@@ -7,6 +7,7 @@
 #define _PART_H
 
 #include <blk.h>
+#include <fs_common.h>
 #include <ide.h>
 #include <u-boot/uuid.h>
 #include <linker_lists.h>
@@ -84,6 +85,7 @@ struct disk_partition {
 #ifdef CONFIG_DOS_PARTITION
 	uchar	sys_ind;	/* partition type			*/
 #endif
+	enum fs_type_t fs_type;	/* type used for hostfs and virtio-fs */
 };
 
 /* Accessors for struct disk_partition field ->uuid */