The kernel patch [1] added a sysfs interface to read the device fsid from
the kernel, which is a better way to know the fsid of the device (rather
than reading the superblock). It also works if in case the device is
missing. Furthermore, the sysfs interface is readable from the non-root
user.

So use this new sysfs interface here to read the fsid.

[1]
btrfs: sysfs add devinfo/fsid to retrieve fsid from the device

Signed-off-by: Anand Jain <redacted>
---
 cmds/filesystem-usage.c | 38 ++++++++++++++++++++++++++++++--------
 1 file changed, 30 insertions(+), 8 deletions(-)

diff --git a/cmds/filesystem-usage.c b/cmds/filesystem-usage.c
index 0dfc798e8dcc..f658c27b9609 100644
--- a/cmds/filesystem-usage.c
+++ b/cmds/filesystem-usage.c

@@ -40,6 +40,7 @@
 #include "common/help.h"
 #include "common/device-utils.h"
 #include "common/open-utils.h"
+#include "common/path-utils.h"
 
 /*
  * Add the chunk info to the chunk_info list

@@ -706,14 +707,33 @@ out:
 	return ret;
 }
 
-static int device_is_seed(const char *dev_path, u8 *mnt_fsid)
+static int device_is_seed(int fd, const char *dev_path, u64 devid, u8 *mnt_fsid)
 {
+	char fsidparse[BTRFS_UUID_UNPARSED_SIZE];
+	char fsid_path[PATH_MAX];
+	char devid_str[20];
 	uuid_t fsid;
-	int ret;
+	int ret = -1;
+	int sysfs_fd;
+
+	snprintf(devid_str, 20, "%llu", devid);
+	/* devinfo/<devid>/fsid */
+	path_cat3_out(fsid_path, "devinfo", devid_str, "fsid");
+
+	/* /sys/fs/btrfs/<fsid>/devinfo/<devid>/fsid */
+	sysfs_fd = sysfs_open_fsid_file(fd, fsid_path);
+	if (sysfs_fd >= 0) {
+		sysfs_read_file(sysfs_fd, fsidparse, BTRFS_UUID_UNPARSED_SIZE);
+		fsidparse[BTRFS_UUID_UNPARSED_SIZE - 1] = 0;
+		ret = uuid_parse(fsidparse, fsid);
+		close(sysfs_fd);
+	}
 
-	ret = dev_to_fsid(dev_path, fsid);