Commit 12907fc7 authored by David Sterba's avatar David Sterba Committed by Chris Mason
Browse files

btrfs: extend balance filter limit to take minimum and maximum 



The 'limit' filter is underdesigned, it should have been a range for
[min,max], with some relaxed semantics when one of the bounds is
missing. Besides that, using a full u64 for a single value is a waste of
bytes.

Let's fix both by extending the use of the u64 bytes for the [min,max]
range. This can be done in a backward compatible way, the range will be
interpreted only if the appropriate flag is set
(BTRFS_BALANCE_ARGS_LIMIT_RANGE).

Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 2849a854

fs/btrfs/ctree.h

+12 −2
Original line number Diff line number Diff line
@@ -846,8 +846,18 @@ struct btrfs_disk_balance_args { 
	/* BTRFS_BALANCE_ARGS_* */

	__le64 flags;



	/* BTRFS_BALANCE_ARGS_LIMIT value */

	/*

	 * BTRFS_BALANCE_ARGS_LIMIT with value 'limit'

	 * BTRFS_BALANCE_ARGS_LIMIT_RANGE - the extend version can use minimum

	 * and maximum

	 */

	union {

		__le64 limit;

		struct {

			__le32 limit_min;

			__le32 limit_max;

		};

	};



	__le64 unused[7];

} __attribute__ ((__packed__));

fs/btrfs/volumes.c

+42 −0
Original line number Diff line number Diff line
@@ -3300,6 +3300,16 @@ static int should_balance_chunk(struct btrfs_root *root, 
			return 0;

		else

			bargs->limit--;

	} else if ((bargs->flags & BTRFS_BALANCE_ARGS_LIMIT_RANGE)) {

		/*

		 * Same logic as the 'limit' filter; the minimum cannot be

		 * determined here because we do not have the global informatoin

		 * about the count of all chunks that satisfy the filters.

		 */

		if (bargs->limit_max == 0)

			return 0;

		else

			bargs->limit_max--;

	}



	return 1;
@@ -3314,6 +3324,7 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info) 
	struct btrfs_device *device;

	u64 old_size;

	u64 size_to_free;

	u64 chunk_type;

	struct btrfs_chunk *chunk;

	struct btrfs_path *path;

	struct btrfs_key key;
@@ -3324,9 +3335,13 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info) 
	int ret;

	int enospc_errors = 0;

	bool counting = true;

	/* The single value limit and min/max limits use the same bytes in the */

	u64 limit_data = bctl->data.limit;

	u64 limit_meta = bctl->meta.limit;

	u64 limit_sys = bctl->sys.limit;

	u32 count_data = 0;

	u32 count_meta = 0;

	u32 count_sys = 0;



	/* step one make some room on all the devices */

	devices = &fs_info->fs_devices->devices;
@@ -3367,6 +3382,10 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info) 
	spin_unlock(&fs_info->balance_lock);

again:

	if (!counting) {

		/*

		 * The single value limit and min/max limits use the same bytes

		 * in the

		 */

		bctl->data.limit = limit_data;

		bctl->meta.limit = limit_meta;

		bctl->sys.limit = limit_sys;
@@ -3414,6 +3433,7 @@ again: 
		}



		chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);

		chunk_type = btrfs_chunk_type(leaf, chunk);



		if (!counting) {

			spin_lock(&fs_info->balance_lock);
@@ -3434,6 +3454,28 @@ again: 
			spin_lock(&fs_info->balance_lock);

			bctl->stat.expected++;

			spin_unlock(&fs_info->balance_lock);



			if (chunk_type & BTRFS_BLOCK_GROUP_DATA)

				count_data++;

			else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)

				count_sys++;

			else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)

				count_meta++;



			goto loop;

		}



		/*

		 * Apply limit_min filter, no need to check if the LIMITS

		 * filter is used, limit_min is 0 by default

		 */

		if (((chunk_type & BTRFS_BLOCK_GROUP_DATA) &&

					count_data < bctl->data.limit_min)

				|| ((chunk_type & BTRFS_BLOCK_GROUP_METADATA) &&

					count_meta < bctl->meta.limit_min)

				|| ((chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) &&

					count_sys < bctl->sys.limit_min)) {

			mutex_unlock(&fs_info->delete_unused_bgs_mutex);

			goto loop;

		}

fs/btrfs/volumes.h

+1 −0
Original line number Diff line number Diff line
@@ -380,6 +380,7 @@ struct map_lookup { 
#define BTRFS_BALANCE_ARGS_DRANGE	(1ULL << 3)

#define BTRFS_BALANCE_ARGS_VRANGE	(1ULL << 4)

#define BTRFS_BALANCE_ARGS_LIMIT	(1ULL << 5)

#define BTRFS_BALANCE_ARGS_LIMIT_RANGE	(1ULL << 6)



#define BTRFS_BALANCE_ARGS_MASK			\

	(BTRFS_BALANCE_ARGS_PROFILES |		\

include/uapi/linux/btrfs.h

+12 −1
Original line number Diff line number Diff line
@@ -217,7 +217,18 @@ struct btrfs_balance_args { 


	__u64 flags;



	/*

	 * BTRFS_BALANCE_ARGS_LIMIT with value 'limit'

	 * BTRFS_BALANCE_ARGS_LIMIT_RANGE - the extend version can use minimum

	 * and maximum

	 */

	union {

		__u64 limit;		/* limit number of processed chunks */

		struct {

			__u32 limit_min;

			__u32 limit_max;

		};

	};

	__u64 unused[7];

} __attribute__ ((__packed__));

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