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authorMiao Xie <miaox@cn.fujitsu.com>2013-06-19 10:36:09 +0800
committerJosef Bacik <jbacik@fusionio.com>2013-07-02 11:50:47 -0400
commitf51a4a1826ff810eb9c00cadff8978b028c40756 (patch)
tree20185a1b681194a39513f346f72e6d8ef605b8e1 /fs/btrfs/scrub.c
parent7ee9e4405f264e9eda808aa5ca4522746a1af9c1 (diff)
Btrfs: remove btrfs_sector_sum structure
Using the structure btrfs_sector_sum to keep the checksum value is unnecessary, because the extents that btrfs_sector_sum points to are continuous, we can find out the expected checksums by btrfs_ordered_sum's bytenr and the offset, so we can remove btrfs_sector_sum's bytenr. After removing bytenr, there is only one member in the structure, so it makes no sense to keep the structure, just remove it, and use a u32 array to store the checksum value. By this change, we don't use the while loop to get the checksums one by one. Now, we can get several checksum value at one time, it improved the performance by ~74% on my SSD (31MB/s -> 54MB/s). test command: # dd if=/dev/zero of=/mnt/btrfs/file0 bs=1M count=1024 oflag=sync Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Diffstat (limited to 'fs/btrfs/scrub.c')
-rw-r--r--fs/btrfs/scrub.c16
1 files changed, 5 insertions, 11 deletions
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index cb308a3a9300..63144e4ca9e1 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -2126,8 +2126,7 @@ static int scrub_find_csum(struct scrub_ctx *sctx, u64 logical, u64 len,
u8 *csum)
{
struct btrfs_ordered_sum *sum = NULL;
- int ret = 0;
- unsigned long i;
+ unsigned long index;
unsigned long num_sectors;
while (!list_empty(&sctx->csum_list)) {
@@ -2146,19 +2145,14 @@ static int scrub_find_csum(struct scrub_ctx *sctx, u64 logical, u64 len,
if (!sum)
return 0;
+ index = ((u32)(logical - sum->bytenr)) / sctx->sectorsize;
num_sectors = sum->len / sctx->sectorsize;
- for (i = 0; i < num_sectors; ++i) {
- if (sum->sums[i].bytenr == logical) {
- memcpy(csum, &sum->sums[i].sum, sctx->csum_size);
- ret = 1;
- break;
- }
- }
- if (ret && i == num_sectors - 1) {
+ memcpy(csum, sum->sums + index, sctx->csum_size);
+ if (index == num_sectors - 1) {
list_del(&sum->list);
kfree(sum);
}
- return ret;
+ return 1;
}
/* scrub extent tries to collect up to 64 kB for each bio */