diff mbox series

[v3,3/4] btrfs: add device major-minor info in the struct btrfs_device

Message ID 6531891b2bcb2d68baf4e0cfbc37e6d9d614cbef.1641535030.git.anand.jain@oracle.com (mailing list archive)
State New, archived
Headers show
Series btrfs: match device by dev_t | expand

Commit Message

Anand Jain Jan. 7, 2022, 1:04 p.m. UTC 
Internally it is common to use the major-minor number to identify a device
and, at a few locations in btrfs, we use the major-minor number to match
the device.

So when we identify a new btrfs device through device add or device
replace or device-scan/ready save the device's major-minor (dev_t) in the
struct btrfs_device so that we don't have to call lookup_bdev() again.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
v3: -

 fs/btrfs/dev-replace.c |  3 +++
 fs/btrfs/volumes.c     | 36 +++++++++++++++---------------------
 fs/btrfs/volumes.h     |  1 +
 3 files changed, 19 insertions(+), 21 deletions(-)

Comments

David Sterba Jan. 7, 2022, 4:20 p.m. UTC | #1 
On Fri, Jan 07, 2022 at 09:04:15PM +0800, Anand Jain wrote:
> Internally it is common to use the major-minor number to identify a device
> and, at a few locations in btrfs, we use the major-minor number to match
> the device.
> 
> So when we identify a new btrfs device through device add or device
> replace or device-scan/ready save the device's major-minor (dev_t) in the
> struct btrfs_device so that we don't have to call lookup_bdev() again.

Sounds good.

> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> ---
> v3: -
> 
>  fs/btrfs/dev-replace.c |  3 +++
>  fs/btrfs/volumes.c     | 36 +++++++++++++++---------------------
>  fs/btrfs/volumes.h     |  1 +
>  3 files changed, 19 insertions(+), 21 deletions(-)
> 
> diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
> index 62b9651ea662..289d6cc1f5db 100644
> --- a/fs/btrfs/dev-replace.c
> +++ b/fs/btrfs/dev-replace.c
> @@ -302,6 +302,9 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
>  		goto error;
>  	}
>  	rcu_assign_pointer(device->name, name);
> +	ret = lookup_bdev(device_path, &device->devt);
> +	if (ret)
> +		goto error;
>  
>  	set_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
>  	device->generation = 0;
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index cb43ee5925ad..33b5f40d030a 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -817,11 +817,17 @@ static noinline struct btrfs_device *device_list_add(const char *path,
>  	struct rcu_string *name;
>  	u64 found_transid = btrfs_super_generation(disk_super);
>  	u64 devid = btrfs_stack_device_id(&disk_super->dev_item);
> +	dev_t path_devt;
> +	int error;
>  	bool has_metadata_uuid = (btrfs_super_incompat_flags(disk_super) &
>  		BTRFS_FEATURE_INCOMPAT_METADATA_UUID);
>  	bool fsid_change_in_progress = (btrfs_super_flags(disk_super) &
>  					BTRFS_SUPER_FLAG_CHANGING_FSID_V2);
>  
> +	error = lookup_bdev(path, &path_devt);
> +	if (error)
> +		return ERR_PTR(error);
> +
>  	if (fsid_change_in_progress) {
>  		if (!has_metadata_uuid)
>  			fs_devices = find_fsid_inprogress(disk_super);
> @@ -904,6 +910,7 @@ static noinline struct btrfs_device *device_list_add(const char *path,
>  			return ERR_PTR(-ENOMEM);
>  		}
>  		rcu_assign_pointer(device->name, name);
> +		device->devt = path_devt;
>  
>  		list_add_rcu(&device->dev_list, &fs_devices->devices);
>  		fs_devices->num_devices++;
> @@ -966,16 +973,7 @@ static noinline struct btrfs_device *device_list_add(const char *path,
>  		 * make sure it's the same device if the device is mounted
>  		 */
>  		if (device->bdev) {
> -			int error;
> -			dev_t path_dev;
> -
> -			error = lookup_bdev(path, &path_dev);
> -			if (error) {
> -				mutex_unlock(&fs_devices->device_list_mutex);
> -				return ERR_PTR(error);
> -			}
> -
> -			if (device->bdev->bd_dev != path_dev) {
> +			if (device->devt != path_devt) {
>  				mutex_unlock(&fs_devices->device_list_mutex);
>  				/*
>  				 * device->fs_info may not be reliable here, so
> @@ -1008,6 +1006,7 @@ static noinline struct btrfs_device *device_list_add(const char *path,
>  			fs_devices->missing_devices--;
>  			clear_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state);
>  		}
> +		device->devt = path_devt;
>  	}
>  
>  	/*
> @@ -1421,14 +1420,8 @@ struct btrfs_device *btrfs_scan_one_device(const char *path, fmode_t flags,
>  	}
>  
>  	device = device_list_add(path, disk_super, &new_device_added);
> -	if (!IS_ERR(device)) {
> -		if (new_device_added) {
> -			dev_t devt;
> -
> -			if (!lookup_bdev(path, &devt))
> -				btrfs_free_stale_devices(devt, device);
> -		}
> -	}
> +	if (!IS_ERR(device) && new_device_added)
> +		btrfs_free_stale_devices(device->devt, device);
>  
>  	btrfs_release_disk_super(disk_super);
>  
> @@ -2658,7 +2651,6 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
>  	int ret = 0;
>  	bool seeding_dev = false;
>  	bool locked = false;
> -	dev_t devt;
>  
>  	if (sb_rdonly(sb) && !fs_devices->seeding)
>  		return -EROFS;
> @@ -2708,6 +2700,9 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
>  
>  	device->fs_info = fs_info;
>  	device->bdev = bdev;
> +	ret = lookup_bdev(device_path, &device->devt);
> +	if (ret)
> +		goto error_free_device;
>  
>  	ret = btrfs_get_dev_zone_info(device, false);
>  	if (ret)
> @@ -2853,8 +2848,7 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
>  	 * We can ignore the return value as it typically returns -EINVAL and
>  	 * only succeeds if the device was an alien.
>  	 */
> -	if (!lookup_bdev(device_path, &devt))
> -		btrfs_forget_devices(devt);
> +	btrfs_forget_devices(device->devt);
>  
>  	/* Update ctime/mtime for blkid or udev */
>  	update_dev_time(device_path);
> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
> index 76215de8ce34..d75450a11713 100644
> --- a/fs/btrfs/volumes.h
> +++ b/fs/btrfs/volumes.h
> @@ -73,6 +73,7 @@ struct btrfs_device {
>  	/* the mode sent to blkdev_get */
>  	fmode_t mode;
>  
> +	dev_t devt;

Please add a comment.

>  	unsigned long dev_state;
>  	blk_status_t last_flush_error;
>  
> -- 
> 2.33.1
Anand Jain Jan. 10, 2022, 6:58 a.m. UTC | #2 
>> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
>> index 76215de8ce34..d75450a11713 100644
>> --- a/fs/btrfs/volumes.h
>> +++ b/fs/btrfs/volumes.h
>> @@ -73,6 +73,7 @@ struct btrfs_device {
>>   	/* the mode sent to blkdev_get */
>>   	fmode_t mode;
>>   
>> +	dev_t devt;
> 
> Please add a comment.

  Added in v4.

Thanks,

> 
>>   	unsigned long dev_state;
>>   	blk_status_t last_flush_error;
>>   
>> -- 
>> 2.33.1
diff mbox series

Patch

diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 62b9651ea662..289d6cc1f5db 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -302,6 +302,9 @@  static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
 		goto error;
 	}
 	rcu_assign_pointer(device->name, name);
+	ret = lookup_bdev(device_path, &device->devt);
+	if (ret)
+		goto error;
 
 	set_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
 	device->generation = 0;
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index cb43ee5925ad..33b5f40d030a 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -817,11 +817,17 @@  static noinline struct btrfs_device *device_list_add(const char *path,
 	struct rcu_string *name;
 	u64 found_transid = btrfs_super_generation(disk_super);
 	u64 devid = btrfs_stack_device_id(&disk_super->dev_item);
+	dev_t path_devt;
+	int error;
 	bool has_metadata_uuid = (btrfs_super_incompat_flags(disk_super) &
 		BTRFS_FEATURE_INCOMPAT_METADATA_UUID);
 	bool fsid_change_in_progress = (btrfs_super_flags(disk_super) &
 					BTRFS_SUPER_FLAG_CHANGING_FSID_V2);
 
+	error = lookup_bdev(path, &path_devt);
+	if (error)
+		return ERR_PTR(error);
+
 	if (fsid_change_in_progress) {
 		if (!has_metadata_uuid)
 			fs_devices = find_fsid_inprogress(disk_super);
@@ -904,6 +910,7 @@  static noinline struct btrfs_device *device_list_add(const char *path,
 			return ERR_PTR(-ENOMEM);
 		}
 		rcu_assign_pointer(device->name, name);
+		device->devt = path_devt;
 
 		list_add_rcu(&device->dev_list, &fs_devices->devices);
 		fs_devices->num_devices++;
@@ -966,16 +973,7 @@  static noinline struct btrfs_device *device_list_add(const char *path,
 		 * make sure it's the same device if the device is mounted
 		 */
 		if (device->bdev) {
-			int error;
-			dev_t path_dev;
-
-			error = lookup_bdev(path, &path_dev);
-			if (error) {
-				mutex_unlock(&fs_devices->device_list_mutex);
-				return ERR_PTR(error);
-			}
-
-			if (device->bdev->bd_dev != path_dev) {
+			if (device->devt != path_devt) {
 				mutex_unlock(&fs_devices->device_list_mutex);
 				/*
 				 * device->fs_info may not be reliable here, so
@@ -1008,6 +1006,7 @@  static noinline struct btrfs_device *device_list_add(const char *path,
 			fs_devices->missing_devices--;
 			clear_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state);
 		}
+		device->devt = path_devt;
 	}
 
 	/*
@@ -1421,14 +1420,8 @@  struct btrfs_device *btrfs_scan_one_device(const char *path, fmode_t flags,
 	}
 
 	device = device_list_add(path, disk_super, &new_device_added);
-	if (!IS_ERR(device)) {
-		if (new_device_added) {
-			dev_t devt;
-
-			if (!lookup_bdev(path, &devt))
-				btrfs_free_stale_devices(devt, device);
-		}
-	}
+	if (!IS_ERR(device) && new_device_added)
+		btrfs_free_stale_devices(device->devt, device);
 
 	btrfs_release_disk_super(disk_super);
 
@@ -2658,7 +2651,6 @@  int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
 	int ret = 0;
 	bool seeding_dev = false;
 	bool locked = false;
-	dev_t devt;
 
 	if (sb_rdonly(sb) && !fs_devices->seeding)
 		return -EROFS;
@@ -2708,6 +2700,9 @@  int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
 
 	device->fs_info = fs_info;
 	device->bdev = bdev;
+	ret = lookup_bdev(device_path, &device->devt);
+	if (ret)
+		goto error_free_device;
 
 	ret = btrfs_get_dev_zone_info(device, false);
 	if (ret)
@@ -2853,8 +2848,7 @@  int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
 	 * We can ignore the return value as it typically returns -EINVAL and
 	 * only succeeds if the device was an alien.
 	 */
-	if (!lookup_bdev(device_path, &devt))
-		btrfs_forget_devices(devt);
+	btrfs_forget_devices(device->devt);
 
 	/* Update ctime/mtime for blkid or udev */
 	update_dev_time(device_path);
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 76215de8ce34..d75450a11713 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -73,6 +73,7 @@  struct btrfs_device {
 	/* the mode sent to blkdev_get */
 	fmode_t mode;
 
+	dev_t devt;
 	unsigned long dev_state;
 	blk_status_t last_flush_error;