btrfs: Make btrfs_find_device_missing_or_by_path return directly a device

This function returns a numeric error value and additionally the
device found in one of its input parameters. Simplify this by making
the function directly return a pointer to btrfs_device. Additionally
adjust the caller to handle the case when we want to remove the
'missing' device and ENOENT is returned to return the expected
positive error value, parsed by progs. Finally, unexport the function
since it's not called outside of volume.c. No functional changes.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/volumes.c

@@ -2134,11 +2134,10 @@ static struct btrfs_device *btrfs_find_device_by_path(
 	return device;
 }
 
-int btrfs_find_device_missing_or_by_path(struct btrfs_fs_info *fs_info,
-					 const char *device_path,
-					 struct btrfs_device **device)
+static struct btrfs_device *btrfs_find_device_missing_or_by_path(
+		struct btrfs_fs_info *fs_info, const char *device_path)
 {
-	*device = NULL;
+	struct btrfs_device *device = NULL;
 	if (strcmp(device_path, "missing") == 0) {
 		struct list_head *devices;
 		struct btrfs_device *tmp;
@@ -2147,20 +2146,18 @@ int btrfs_find_device_missing_or_by_path(struct btrfs_fs_info *fs_info,
 		list_for_each_entry(tmp, devices, dev_list) {
 			if (test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
 					&tmp->dev_state) && !tmp->bdev) {
-				*device = tmp;
+				device = tmp;
 				break;
 			}
 		}
 
-		if (!*device)
-			return BTRFS_ERROR_DEV_MISSING_NOT_FOUND;
+		if (!device)
+			return ERR_PTR(-ENOENT);
 	} else {
-		*device = btrfs_find_device_by_path(fs_info, device_path);
-		if (IS_ERR(*device))
-			return PTR_ERR(*device);
+		device = btrfs_find_device_by_path(fs_info, device_path);
 	}
 
-	return 0;
+	return device;
 }
 
 /*
@@ -2170,10 +2167,9 @@ int btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info, u64 devid,
 				 const char *devpath,
 				 struct btrfs_device **device)
 {
-	int ret;
+	int ret = 0;
 
 	if (devid) {
-		ret = 0;
 		*device = btrfs_find_device(fs_info, devid, NULL, NULL);
 		if (!*device)
 			ret = -ENOENT;
@@ -2181,8 +2177,14 @@ int btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info, u64 devid,
 		if (!devpath || !devpath[0])
 			return -EINVAL;
 
-		ret = btrfs_find_device_missing_or_by_path(fs_info, devpath,
-							   device);
+		*device = btrfs_find_device_missing_or_by_path(fs_info, devpath);
+		if (IS_ERR(*device)) {
+			if (PTR_ERR(*device) == -ENOENT &&
+			    strcmp(devpath, "missing") == 0)
+				ret = BTRFS_ERROR_DEV_MISSING_NOT_FOUND;
+			else
+				ret = PTR_ERR(*device);
+		}
 	}
 	return ret;
 }

fs/btrfs/volumes.h

@@ -410,9 +410,6 @@ int btrfs_close_devices(struct btrfs_fs_devices *fs_devices);
 void btrfs_free_extra_devids(struct btrfs_fs_devices *fs_devices, int step);
 void btrfs_assign_next_active_device(struct btrfs_device *device,
 				     struct btrfs_device *this_dev);
-int btrfs_find_device_missing_or_by_path(struct btrfs_fs_info *fs_info,
-					 const char *device_path,
-					 struct btrfs_device **device);
 int btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info, u64 devid,
 					 const char *devpath,
 					 struct btrfs_device **device);