[PATCH 2/2] btrfs-progs: do not zone reset on emulated zoned mode

[Naohiro Aota <naohiro.aota@wdc.com>]

We cannot zone reset a regular file with emulated zones. So, mkfs.btrfs on
such a file cause a following error.

ERROR: zoned: failed to reset device '/home/naota/tmp/btrfs.img' zones: Inappropriate ioctl for device

Intorduce btrfs_zoned_device_info->emulated to distinguish the zones are
emulated or not. And, use it to decide it needs zone reset or not.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 common/device-utils.c | 27 +++++++++++++++------------
 kernel-shared/zoned.c |  2 ++
 kernel-shared/zoned.h |  1 +
 3 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/common/device-utils.c b/common/device-utils.c
index 1c853545c6ad..503705c43754 100644
--- a/common/device-utils.c
+++ b/common/device-utils.c
@@ -220,18 +220,21 @@ int btrfs_prepare_device(int fd, const char *file, u64 *block_count_ret,
 			      file);
 			return 1;
 		}
-		if (opflags & PREP_DEVICE_VERBOSE)
-			printf("Resetting device zones %s (%u zones) ...\n",
-			       file, zinfo->nr_zones);
-		/*
-		 * We cannot ignore zone reset errors for a zoned block
-		 * device as this could result in the inability to write to
-		 * non-empty sequential zones of the device.
-		 */
-		if (btrfs_reset_all_zones(fd, zinfo)) {
-			error("zoned: failed to reset device '%s' zones: %m",
-			      file);
-			goto err;
+
+		if (!zinfo->emulated) {
+			if (opflags & PREP_DEVICE_VERBOSE)
+				printf("Resetting device zones %s (%u zones) ...\n",
+				       file, zinfo->nr_zones);
+			/*
+			 * We cannot ignore zone reset errors for a zoned block
+			 * device as this could result in the inability to write
+			 * to non-empty sequential zones of the device.
+			 */
+			if (btrfs_reset_all_zones(fd, zinfo)) {
+				error("zoned: failed to reset device '%s' zones: %m",
+				      file);
+				goto err;
+			}
 		}
 	} else if (opflags & PREP_DEVICE_DISCARD) {
 		/*
diff --git a/kernel-shared/zoned.c b/kernel-shared/zoned.c
index 891a2c0aeef2..6e46354b8b52 100644
--- a/kernel-shared/zoned.c
+++ b/kernel-shared/zoned.c
@@ -346,6 +346,7 @@ static int report_zones(int fd, const char *file,
 				error("zoned: ioctl BLKREPORTZONE failed (%m)");
 				exit(1);
 			}
+			zinfo->emulated = false;
 		} else {
 			ret = emulate_report_zones(file, fd,
 						   sector << SECTOR_SHIFT,
@@ -354,6 +355,7 @@ static int report_zones(int fd, const char *file,
 				error("zoned: failed to emulate BLKREPORTZONE");
 				exit(1);
 			}
+			zinfo->emulated = true;
 		}
 
 		if (!rep->nr_zones)
diff --git a/kernel-shared/zoned.h b/kernel-shared/zoned.h
index 99f8e9a2faac..66cf081b84c3 100644
--- a/kernel-shared/zoned.h
+++ b/kernel-shared/zoned.h
@@ -54,6 +54,7 @@ struct btrfs_zoned_device_info {
 	u64		        max_zone_append_size;
 	u32			nr_zones;
 	struct blk_zone		*zones;
+	bool			emulated;
 };
 
 enum btrfs_zoned_model zoned_model(const char *file);
-- 
2.33.0