libblkid: optimize ioctl calls in blkid_probe_set_device()

* call FDGETFDCSTAT only for block devices
* don't check floppies for device-mapper, CD-ROM features or zones

Signed-off-by: Karel Zak <kzak@redhat.com>

libblkid/src/probe.c

@@ -880,6 +880,7 @@ int blkid_probe_set_device(blkid_probe pr, int fd,
 	struct stat sb;
 	uint64_t devsiz = 0;
 	char *dm_uuid = NULL;
+	int is_floppy = 0;
 
 	blkid_reset_probe(pr);
 	blkid_probe_reset_buffers(pr);
@@ -911,35 +912,6 @@ int blkid_probe_set_device(blkid_probe pr, int fd,
 	if (fd < 0)
 		return 1;
 
-#ifdef FDGETFDCSTAT
-	{
-		/*
-		 * Re-open without O_NONBLOCK for floppy device.
-		 *
-		 * Since kernel commit c7e9d0020361f4308a70cdfd6d5335e273eb8717
-		 * floppy drive works bad when opened with O_NONBLOCK.
-		 */
-		struct floppy_fdc_state flst;
-
-		if (ioctl(fd, FDGETFDCSTAT, &flst) >= 0) {
-			int flags = fcntl(fd, F_GETFL, 0);
-
-			if (flags < 0)
-				goto err;
-			if (flags & O_NONBLOCK) {
-				flags &= ~O_NONBLOCK;
-
-				fd = ul_reopen(fd, flags | O_CLOEXEC);
-				if (fd < 0)
-					goto err;
-
-				pr->flags |= BLKID_FL_PRIVATE_FD;
-				pr->fd = fd;
-			}
-		}
-		errno = 0;
-	}
-#endif
 
 #if defined(POSIX_FADV_RANDOM) && defined(HAVE_POSIX_FADVISE)
 	/* Disable read-ahead */
@@ -990,7 +962,38 @@ int blkid_probe_set_device(blkid_probe pr, int fd,
 	if (pr->size <= 1440 * 1024 && !S_ISCHR(sb.st_mode))
 		pr->flags |= BLKID_FL_TINY_DEV;
 
+#ifdef FDGETFDCSTAT
+	if (S_ISBLK(sb.st_mode)) {
+		/*
+		 * Re-open without O_NONBLOCK for floppy device.
+		 *
+		 * Since kernel commit c7e9d0020361f4308a70cdfd6d5335e273eb8717
+		 * floppy drive works bad when opened with O_NONBLOCK.
+		 */
+		struct floppy_fdc_state flst;
+
+		if (ioctl(fd, FDGETFDCSTAT, &flst) >= 0) {
+			int flags = fcntl(fd, F_GETFL, 0);
+
+			if (flags < 0)
+				goto err;
+			if (flags & O_NONBLOCK) {
+				flags &= ~O_NONBLOCK;
+
+				fd = ul_reopen(fd, flags | O_CLOEXEC);
+				if (fd < 0)
+					goto err;
+
+				pr->flags |= BLKID_FL_PRIVATE_FD;
+				pr->fd = fd;
+			}
+			is_floppy = 1;
+		}
+		errno = 0;
+	}
+#endif
 	if (S_ISBLK(sb.st_mode) &&
+	    !is_floppy &&
 	    sysfs_devno_is_dm_private(sb.st_rdev, &dm_uuid)) {
 		DBG(LOWPROBE, ul_debug("ignore private device mapper device"));
 		pr->flags |= BLKID_FL_NOSCAN_DEV;
@@ -1000,6 +1003,7 @@ int blkid_probe_set_device(blkid_probe pr, int fd,
 	else if (S_ISBLK(sb.st_mode) &&
 	    !blkid_probe_is_tiny(pr) &&
 	    !dm_uuid &&
+	    !is_floppy &&
 	    blkid_probe_is_wholedisk(pr)) {
 
 		long last_written = 0;
@@ -1051,7 +1055,7 @@ int blkid_probe_set_device(blkid_probe pr, int fd,
 	free(dm_uuid);
 
 # ifdef BLKGETZONESZ
-	if (S_ISBLK(sb.st_mode)) {
+	if (S_ISBLK(sb.st_mode) && !is_floppy) {
 		uint32_t zone_size_sector;
 
 		if (!ioctl(pr->fd, BLKGETZONESZ, &zone_size_sector))