cc353a8be2
Currently btrfs uses fixed stripe length (64K), thus u32 is wide enough for the usage. Furthermore, even in the future we choose to enlarge stripe length to larger values, I don't believe we would want stripe as large as 4G or larger. So this patch will reduce the width for all in-memory structures and parameters, this involves: - RAID56 related function argument lists This allows us to do direct division related to stripe_len. Although we will use bits shift to replace the division anyway. - btrfs_io_geometry structure This involves one change to simplify the calculation of both @stripe_nr and @stripe_offset, using div64_u64_rem(). And add extra sanity check to make sure @stripe_offset is always small enough for u32. This saves 8 bytes for the structure. - map_lookup structure This convert @stripe_len to u32, which saves 8 bytes. (saved 4 bytes, and removed a 4-bytes hole) Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
55 lines
1.6 KiB
C
55 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2012 Fusion-io All rights reserved.
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* Copyright (C) 2012 Intel Corp. All rights reserved.
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*/
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#ifndef BTRFS_RAID56_H
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#define BTRFS_RAID56_H
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static inline int nr_parity_stripes(const struct map_lookup *map)
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{
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if (map->type & BTRFS_BLOCK_GROUP_RAID5)
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return 1;
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else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
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return 2;
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else
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return 0;
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}
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static inline int nr_data_stripes(const struct map_lookup *map)
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{
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return map->num_stripes - nr_parity_stripes(map);
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}
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#define RAID5_P_STRIPE ((u64)-2)
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#define RAID6_Q_STRIPE ((u64)-1)
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#define is_parity_stripe(x) (((x) == RAID5_P_STRIPE) || \
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((x) == RAID6_Q_STRIPE))
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struct btrfs_raid_bio;
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struct btrfs_device;
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int raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
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u32 stripe_len, int mirror_num, int generic_io);
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int raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc, u32 stripe_len);
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void raid56_add_scrub_pages(struct btrfs_raid_bio *rbio, struct page *page,
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u64 logical);
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struct btrfs_raid_bio *raid56_parity_alloc_scrub_rbio(struct bio *bio,
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struct btrfs_io_context *bioc, u32 stripe_len,
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struct btrfs_device *scrub_dev,
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unsigned long *dbitmap, int stripe_nsectors);
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void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio);
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struct btrfs_raid_bio *
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raid56_alloc_missing_rbio(struct bio *bio, struct btrfs_io_context *bioc,
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u64 length);
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void raid56_submit_missing_rbio(struct btrfs_raid_bio *rbio);
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int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info);
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void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info);
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#endif
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