[PATCH v4 5/9] btrfs: scrub: cleanup the non-RAID56 branches in scrub_stripe()

Qu Wenruo
2022-03-11T07:39:18Z

Since we have moved all other profiles handling into their own
functions, now the main body of scrub_stripe() is just handling RAID56
profiles.

There is no need to address other profiles in the main loop of
scrub_stripe(), so we can remove those dead branches.

Since we're here, also slightly change the timing of initialization of
variables like @offset, @increment and @logical.

Especially for @logical, we don't really need to initialize it for
btrfs_extent_root()/btrfs_csum_root(), we can use bg->start for that
purpose.

Now those variables are only initialize for RAID56 branches.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
fs/btrfs/scrub.c | 128 +++++++++++++++++++----------------------------
1 file changed, 51 insertions(+), 77 deletions(-)

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 04445ffd83c8..ddfbca03791b 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -3527,14 +3527,12 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
u64 flags;
int ret;
int slot;
- u64 nstripes;
struct extent_buffer *l;
u64 physical = map->stripes[stripe_index].physical;
u64 logical;
u64 logic_end;
const u64 physical_end = physical + dev_extent_len;
u64 generation;
- int mirror_num;
struct btrfs_key key;
u64 increment;
u64 offset;
@@ -3551,28 +3549,6 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
int extent_mirror_num;
int stop_loop = 0;

- offset = 0;
- nstripes = div64_u64(dev_extent_len, map->stripe_len);
- mirror_num = 1;
- increment = map->stripe_len;
- if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
- offset = map->stripe_len * stripe_index;
- increment = map->stripe_len * map->num_stripes;
- } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
- int factor = map->num_stripes / map->sub_stripes;
- offset = map->stripe_len * (stripe_index / map->sub_stripes);
- increment = map->stripe_len * factor;
- mirror_num = stripe_index % map->sub_stripes + 1;
- } else if (map->type & BTRFS_BLOCK_GROUP_RAID1_MASK) {
- mirror_num = stripe_index % map->num_stripes + 1;
- } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
- mirror_num = stripe_index % map->num_stripes + 1;
- } else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
- get_raid56_logic_offset(physical, stripe_index, map, &offset,
- NULL);
- increment = map->stripe_len * nr_data_stripes(map);
- }
-
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
@@ -3586,20 +3562,12 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
path->skip_locking = 1;
path->reada = READA_FORWARD;

- logical = chunk_logical + offset;
- if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
- get_raid56_logic_offset(physical_end, stripe_index,
- map, &logic_end, NULL);
- logic_end += chunk_logical;
- } else {
- logic_end = logical + increment * nstripes;
- }
wait_event(sctx->list_wait,
atomic_read(&sctx->bios_in_flight) == 0);
scrub_blocked_if_needed(fs_info);

- root = btrfs_extent_root(fs_info, logical);
- csum_root = btrfs_csum_root(fs_info, logical);
+ root = btrfs_extent_root(fs_info, bg->start);
+ csum_root = btrfs_csum_root(fs_info, bg->start);

/*
* collect all data csums for the stripe to avoid seeking during
@@ -3636,17 +3604,29 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
bg->start, bg->length, scrub_dev,
map->stripes[stripe_index].physical,
stripe_index + 1);
+ offset = 0;
goto out;
}
if (profile & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
ret = scrub_simple_stripe(sctx, root, csum_root, bg, map,
scrub_dev, stripe_index);
+ offset = map->stripe_len * (stripe_index / map->sub_stripes);
goto out;
}

/* Only RAID56 goes through the old code */
ASSERT(map->type & BTRFS_BLOCK_GROUP_RAID56_MASK);
ret = 0;
+
+ /* Calculate the logical end of the stripe */
+ get_raid56_logic_offset(physical_end, stripe_index,
+ map, &logic_end, NULL);
+ logic_end += chunk_logical;
+
+ /* Initialize @offset in case we need to go to out: label */
+ get_raid56_logic_offset(physical, stripe_index, map, &offset, NULL);
+ increment = map->stripe_len * nr_data_stripes(map);
+
while (physical < physical_end) {
/*
* canceled?
@@ -3672,22 +3652,20 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
scrub_blocked_if_needed(fs_info);
}

- if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
- ret = get_raid56_logic_offset(physical, stripe_index,
- map, &logical,
- &stripe_logical);
- logical += chunk_logical;
- if (ret) {
- /* it is parity strip */
- stripe_logical += chunk_logical;
- stripe_end = stripe_logical + increment;
- ret = scrub_raid56_parity(sctx, map, scrub_dev,
- stripe_logical,
- stripe_end);
- if (ret)
- goto out;
- goto skip;
- }
+ ret = get_raid56_logic_offset(physical, stripe_index,
+ map, &logical,
+ &stripe_logical);
+ logical += chunk_logical;
+ if (ret) {
+ /* it is parity strip */
+ stripe_logical += chunk_logical;
+ stripe_end = stripe_logical + increment;
+ ret = scrub_raid56_parity(sctx, map, scrub_dev,
+ stripe_logical,
+ stripe_end);
+ if (ret)
+ goto out;
+ goto skip;
}

if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
@@ -3805,7 +3783,8 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,

extent_physical = extent_logical - logical + physical;
extent_dev = scrub_dev;
- extent_mirror_num = mirror_num;
+ /* For RAID56 data stripes, mirror_num is fixed to 1 */
+ extent_mirror_num = 1;
if (sctx->is_dev_replace)
scrub_remap_extent(fs_info, extent_logical,
extent_len, &extent_physical,
@@ -3836,33 +3815,28 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,

if (extent_logical + extent_len <
key.objectid + bytes) {
- if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
- /*
- * loop until we find next data stripe
- * or we have finished all stripes.
- */
+ /*
+ * loop until we find next data stripe
+ * or we have finished all stripes.
+ */
loop:
- physical += map->stripe_len;
- ret = get_raid56_logic_offset(physical,
- stripe_index, map,
- &logical, &stripe_logical);
- logical += chunk_logical;
-
- if (ret && physical < physical_end) {
- stripe_logical += chunk_logical;
- stripe_end = stripe_logical +
- increment;
- ret = scrub_raid56_parity(sctx,
- map, scrub_dev,
- stripe_logical,
- stripe_end);
- if (ret)
- goto out;
- goto loop;
- }
- } else {
- physical += map->stripe_len;
- logical += increment;
+ physical += map->stripe_len;
+ ret = get_raid56_logic_offset(physical,
+ stripe_index, map,
+ &logical, &stripe_logical);
+ logical += chunk_logical;
+
+ if (ret && physical < physical_end) {
+ stripe_logical += chunk_logical;
+ stripe_end = stripe_logical +
+ increment;
+ ret = scrub_raid56_parity(sctx,
+ map, scrub_dev,
+ stripe_logical,
+ stripe_end);
+ if (ret)
+ goto out;
+ goto loop;
}
if (logical < key.objectid + bytes) {
cond_resched();
--
2.35.1