From 559ca6ea695e3dedc7b6a11ce31fcc6eac398797 Mon Sep 17 00:00:00 2001 From: Nikolay Borisov Date: Wed, 3 Jul 2019 15:32:59 +0300 Subject: [PATCH] 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: Nikolay Borisov Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/super.c | 30 ++++++++++-------------------- 1 file changed, 10 insertions(+), 20 deletions(-) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 78de9d5d80c6..10bc7e6cca75 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -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; -- 2.30.2