| Message ID | 20230531041740.375963-7-hch@lst.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/6] btrfs: remove BTRFS_MAP_DISCARD | expand |
On 2023/5/31 12:17, Christoph Hellwig wrote: > need_full_stripe is just a somewhat complicated way to say > "op != BTRFS_MAP_READ". Just spell that explicit check out, which makes > a lot of the code currently using the helper easier to understand. In fact the old "need_full_stripe" can even be confusing, as BTRFS_MAP_READ with mirror_num > 1 on RAID56 would still need all the stripes. So removing it completely is indeed better. > > Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Qu Wenruo <wqu@suse.com> Thanks, Qu > --- > fs/btrfs/volumes.c | 29 ++++++++++++----------------- > 1 file changed, 12 insertions(+), 17 deletions(-) > > diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c > index 6141a9fe5a28a0..8137c04f31c9cd 100644 > --- a/fs/btrfs/volumes.c > +++ b/fs/btrfs/volumes.c > @@ -6173,11 +6173,6 @@ static void handle_ops_on_dev_replace(enum btrfs_map_op op, > bioc->replace_nr_stripes = nr_extra_stripes; > } > > -static bool need_full_stripe(enum btrfs_map_op op) > -{ > - return (op == BTRFS_MAP_WRITE || op == BTRFS_MAP_GET_READ_MIRRORS); > -} > - > static u64 btrfs_max_io_len(struct map_lookup *map, enum btrfs_map_op op, > u64 offset, u32 *stripe_nr, u64 *stripe_offset, > u64 *full_stripe_start) > @@ -6290,21 +6285,21 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op, > if (map->type & BTRFS_BLOCK_GROUP_RAID0) { > stripe_index = stripe_nr % map->num_stripes; > stripe_nr /= map->num_stripes; > - if (!need_full_stripe(op)) > + if (op == BTRFS_MAP_READ) > mirror_num = 1; > } else if (map->type & BTRFS_BLOCK_GROUP_RAID1_MASK) { > - if (need_full_stripe(op)) > + if (op != BTRFS_MAP_READ) { > num_stripes = map->num_stripes; > - else if (mirror_num) > + } else if (mirror_num) { > stripe_index = mirror_num - 1; > - else { > + } else { > stripe_index = find_live_mirror(fs_info, map, 0, > dev_replace_is_ongoing); > mirror_num = stripe_index + 1; > } > > } else if (map->type & BTRFS_BLOCK_GROUP_DUP) { > - if (need_full_stripe(op)) { > + if (op != BTRFS_MAP_READ) { > num_stripes = map->num_stripes; > } else if (mirror_num) { > stripe_index = mirror_num - 1; > @@ -6318,7 +6313,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op, > stripe_index = (stripe_nr % factor) * map->sub_stripes; > stripe_nr /= factor; > > - if (need_full_stripe(op)) > + if (op != BTRFS_MAP_READ) > num_stripes = map->sub_stripes; > else if (mirror_num) > stripe_index += mirror_num - 1; > @@ -6331,7 +6326,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op, > } > > } else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) { > - if (need_raid_map && (need_full_stripe(op) || mirror_num > 1)) { > + if (need_raid_map && (op != BTRFS_MAP_READ || mirror_num > 1)) { > /* > * Push stripe_nr back to the start of the full stripe > * For those cases needing a full stripe, @stripe_nr > @@ -6366,7 +6361,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op, > > /* We distribute the parity blocks across stripes */ > stripe_index = (stripe_nr + stripe_index) % map->num_stripes; > - if (!need_full_stripe(op) && mirror_num <= 1) > + if (op == BTRFS_MAP_READ && mirror_num <= 1) > mirror_num = 1; > } > } else { > @@ -6406,7 +6401,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op, > */ > if (smap && num_alloc_stripes == 1 && > !((map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) && mirror_num > 1) && > - (!need_full_stripe(op) || !dev_replace_is_ongoing || > + (op == BTRFS_MAP_READ || !dev_replace_is_ongoing || > !dev_replace->tgtdev)) { > set_io_stripe(smap, map, stripe_index, stripe_offset, stripe_nr); > *mirror_num_ret = mirror_num; > @@ -6430,7 +6425,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op, > * It's still mostly the same as other profiles, just with extra rotation. > */ > if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK && need_raid_map && > - (need_full_stripe(op) || mirror_num > 1)) { > + (op != BTRFS_MAP_READ || mirror_num > 1)) { > /* > * For RAID56 @stripe_nr is already the number of full stripes > * before us, which is also the rotation value (needs to modulo > @@ -6457,11 +6452,11 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op, > } > } > > - if (need_full_stripe(op)) > + if (op != BTRFS_MAP_READ) > max_errors = btrfs_chunk_max_errors(map); > > if (dev_replace_is_ongoing && dev_replace->tgtdev != NULL && > - need_full_stripe(op)) { > + op != BTRFS_MAP_READ) { > handle_ops_on_dev_replace(op, bioc, dev_replace, logical, > &num_stripes, &max_errors); > }
On Wed, May 31, 2023 at 04:52:53PM +0800, Qu Wenruo wrote: >> need_full_stripe is just a somewhat complicated way to say >> "op != BTRFS_MAP_READ". Just spell that explicit check out, which makes >> a lot of the code currently using the helper easier to understand. > > In fact the old "need_full_stripe" can even be confusing, as > BTRFS_MAP_READ with mirror_num > 1 on RAID56 would still need all the > stripes. Yes, that's one of the reasons. And that in general in the conditionals READ/!READ tends to explain the logic better than !need_full_stripe vs need_full_stripe.
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 6141a9fe5a28a0..8137c04f31c9cd 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -6173,11 +6173,6 @@ static void handle_ops_on_dev_replace(enum btrfs_map_op op, bioc->replace_nr_stripes = nr_extra_stripes; } -static bool need_full_stripe(enum btrfs_map_op op) -{ - return (op == BTRFS_MAP_WRITE || op == BTRFS_MAP_GET_READ_MIRRORS); -} - static u64 btrfs_max_io_len(struct map_lookup *map, enum btrfs_map_op op, u64 offset, u32 *stripe_nr, u64 *stripe_offset, u64 *full_stripe_start) @@ -6290,21 +6285,21 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op, if (map->type & BTRFS_BLOCK_GROUP_RAID0) { stripe_index = stripe_nr % map->num_stripes; stripe_nr /= map->num_stripes; - if (!need_full_stripe(op)) + if (op == BTRFS_MAP_READ) mirror_num = 1; } else if (map->type & BTRFS_BLOCK_GROUP_RAID1_MASK) { - if (need_full_stripe(op)) + if (op != BTRFS_MAP_READ) { num_stripes = map->num_stripes; - else if (mirror_num) + } else if (mirror_num) { stripe_index = mirror_num - 1; - else { + } else { stripe_index = find_live_mirror(fs_info, map, 0, dev_replace_is_ongoing); mirror_num = stripe_index + 1; } } else if (map->type & BTRFS_BLOCK_GROUP_DUP) { - if (need_full_stripe(op)) { + if (op != BTRFS_MAP_READ) { num_stripes = map->num_stripes; } else if (mirror_num) { stripe_index = mirror_num - 1; @@ -6318,7 +6313,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op, stripe_index = (stripe_nr % factor) * map->sub_stripes; stripe_nr /= factor; - if (need_full_stripe(op)) + if (op != BTRFS_MAP_READ) num_stripes = map->sub_stripes; else if (mirror_num) stripe_index += mirror_num - 1; @@ -6331,7 +6326,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op, } } else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) { - if (need_raid_map && (need_full_stripe(op) || mirror_num > 1)) { + if (need_raid_map && (op != BTRFS_MAP_READ || mirror_num > 1)) { /* * Push stripe_nr back to the start of the full stripe * For those cases needing a full stripe, @stripe_nr @@ -6366,7 +6361,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op, /* We distribute the parity blocks across stripes */ stripe_index = (stripe_nr + stripe_index) % map->num_stripes; - if (!need_full_stripe(op) && mirror_num <= 1) + if (op == BTRFS_MAP_READ && mirror_num <= 1) mirror_num = 1; } } else { @@ -6406,7 +6401,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op, */ if (smap && num_alloc_stripes == 1 && !((map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) && mirror_num > 1) && - (!need_full_stripe(op) || !dev_replace_is_ongoing || + (op == BTRFS_MAP_READ || !dev_replace_is_ongoing || !dev_replace->tgtdev)) { set_io_stripe(smap, map, stripe_index, stripe_offset, stripe_nr); *mirror_num_ret = mirror_num; @@ -6430,7 +6425,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op, * It's still mostly the same as other profiles, just with extra rotation. */ if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK && need_raid_map && - (need_full_stripe(op) || mirror_num > 1)) { + (op != BTRFS_MAP_READ || mirror_num > 1)) { /* * For RAID56 @stripe_nr is already the number of full stripes * before us, which is also the rotation value (needs to modulo @@ -6457,11 +6452,11 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op, } } - if (need_full_stripe(op)) + if (op != BTRFS_MAP_READ) max_errors = btrfs_chunk_max_errors(map); if (dev_replace_is_ongoing && dev_replace->tgtdev != NULL && - need_full_stripe(op)) { + op != BTRFS_MAP_READ) { handle_ops_on_dev_replace(op, bioc, dev_replace, logical, &num_stripes, &max_errors); }
need_full_stripe is just a somewhat complicated way to say "op != BTRFS_MAP_READ". Just spell that explicit check out, which makes a lot of the code currently using the helper easier to understand. Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/btrfs/volumes.c | 29 ++++++++++++----------------- 1 file changed, 12 insertions(+), 17 deletions(-)