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btrfs: check for contiguity in submit_extent_page

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Different loop iterations in btrfs_bio_add_page not only have the same
contiguity parameters, but also any non-initial operation operates on a
fresh bio anyway.

Factor out the contiguity check into a new btrfs_bio_is_contig and only
call it once in submit_extent_page before descending into the
bio_add_page loop.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Christoph Hellwig 2023-02-27 08:17:03 -07:00 • committed by David Sterba
parent 5380311fc8
commit 78a2ef1b7b
1 changed files with 36 additions and 33 deletions
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69
fs/btrfs/extent_io.c
View file

@ -866,6 +866,38 @@ int btrfs_alloc_page_array(unsigned int nr_pages, struct page **page_array)
return 0;
}
static bool btrfs_bio_is_contig(struct btrfs_bio_ctrl *bio_ctrl,
struct page *page, u64 disk_bytenr,
unsigned int pg_offset)
{
struct bio *bio = bio_ctrl->bio;
struct bio_vec *bvec = bio_last_bvec_all(bio);
const sector_t sector = disk_bytenr >> SECTOR_SHIFT;
if (bio_ctrl->compress_type != BTRFS_COMPRESS_NONE) {
/*
* For compression, all IO should have its logical bytenr set
* to the starting bytenr of the compressed extent.
*/
return bio->bi_iter.bi_sector == sector;
}
/*
* The contig check requires the following conditions to be met:
*
* 1) The pages are belonging to the same inode
* This is implied by the call chain.
*
* 2) The range has adjacent logical bytenr
*
* 3) The range has adjacent file offset
* This is required for the usage of btrfs_bio->file_offset.
*/
return bio_end_sector(bio) == sector &&
page_offset(bvec->bv_page) + bvec->bv_offset + bvec->bv_len ==
page_offset(page) + pg_offset;
}
/*
* Attempt to add a page to bio.
*
@ -890,44 +922,11 @@ static int btrfs_bio_add_page(struct btrfs_bio_ctrl *bio_ctrl,
struct bio *bio = bio_ctrl->bio;
u32 bio_size = bio->bi_iter.bi_size;
u32 real_size;
const sector_t sector = disk_bytenr >> SECTOR_SHIFT;
bool contig = false;
ASSERT(bio);
/* The limit should be calculated when bio_ctrl->bio is allocated */
ASSERT(bio_ctrl->len_to_oe_boundary);
if (bio->bi_iter.bi_size == 0) {
/* We can always add a page into an empty bio. */
contig = true;
} else if (bio_ctrl->compress_type == BTRFS_COMPRESS_NONE) {
struct bio_vec *bvec = bio_last_bvec_all(bio);
/*
* The contig check requires the following conditions to be met:
* 1) The pages are belonging to the same inode
* This is implied by the call chain.
*
* 2) The range has adjacent logical bytenr
*
* 3) The range has adjacent file offset
* This is required for the usage of btrfs_bio->file_offset.
*/
if (bio_end_sector(bio) == sector &&
page_offset(bvec->bv_page) + bvec->bv_offset +
bvec->bv_len == page_offset(page) + pg_offset)
contig = true;
} else {
/*
* For compression, all IO should have its logical bytenr
* set to the starting bytenr of the compressed extent.
*/
contig = bio->bi_iter.bi_sector == sector;
}
if (!contig)
return 0;
real_size = min(bio_ctrl->len_to_oe_boundary - bio_size, size);
/*
@ -1024,6 +1023,10 @@ static void submit_extent_page(struct btrfs_bio_ctrl *bio_ctrl,
ASSERT(bio_ctrl->end_io_func);
if (bio_ctrl->bio &&
!btrfs_bio_is_contig(bio_ctrl, page, disk_bytenr, pg_offset))
submit_one_bio(bio_ctrl);
while (cur < pg_offset + size) {
u32 offset = cur - pg_offset;
int added;