Commit 559ca6ea authored by Nikolay Borisov's avatar Nikolay Borisov Committed by David Sterba
Browse files

btrfs: Refactor btrfs_calc_avail_data_space 



Simplify the code by removing variables that don't bring any real value
as well as simplifying the checks when buidling the candidate list of
devices. No functional changes.

Signed-off-by: default avatarNikolay Borisov <nborisov@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent e678934c

fs/btrfs/super.c

+10 −20
Original line number Diff line number Diff line
@@ -1899,11 +1899,10 @@ static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info, 
	struct btrfs_device_info *devices_info;

	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;

	struct btrfs_device *device;

	u64 skip_space;

	u64 type;

	u64 avail_space;

	u64 min_stripe_size;

	int min_stripes, num_stripes = 1;

	int num_stripes = 1;

	int i = 0, nr_devices;

	const struct btrfs_raid_attr *rattr;
@@ -1930,7 +1929,6 @@ static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info, 
	/* calc min stripe number for data space allocation */

	type = btrfs_data_alloc_profile(fs_info);

	rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)];

	min_stripes = rattr->devs_min;



	if (type & BTRFS_BLOCK_GROUP_RAID0)

		num_stripes = nr_devices;
@@ -1956,28 +1954,21 @@ static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info, 
		avail_space = device->total_bytes - device->bytes_used;



		/* align with stripe_len */

		avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);

		avail_space *= BTRFS_STRIPE_LEN;

		avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN);



		/*

		 * In order to avoid overwriting the superblock on the drive,

		 * btrfs starts at an offset of at least 1MB when doing chunk

		 * allocation.

		 *

		 * This ensures we have at least min_stripe_size free space

		 * after excluding 1MB.

		 */

		skip_space = SZ_1M;



		/*

		 * we can use the free space in [0, skip_space - 1], subtract

		 * it from the total.

		 */

		if (avail_space && avail_space >= skip_space)

			avail_space -= skip_space;

		else

			avail_space = 0;



		if (avail_space < min_stripe_size)

		if (avail_space <= SZ_1M + min_stripe_size)

			continue;



		avail_space -= SZ_1M;



		devices_info[i].dev = device;

		devices_info[i].max_avail = avail_space;
@@ -1991,9 +1982,8 @@ static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info, 


	i = nr_devices - 1;

	avail_space = 0;

	while (nr_devices >= min_stripes) {

		if (num_stripes > nr_devices)

			num_stripes = nr_devices;

	while (nr_devices >= rattr->devs_min) {

		num_stripes = min(num_stripes, nr_devices);



		if (devices_info[i].max_avail >= min_stripe_size) {

			int j;

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