| Message ID | 20200911123259.3782926-20-naohiro.aota@wdc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs: zoned block device support | expand |
On Fri, Sep 11, 2020 at 09:32:39PM +0900, Naohiro Aota wrote: > + if (fs_info->max_zone_append_size && > + bio_op(bio) == REQ_OP_WRITE && > + bio->bi_iter.bi_size + size > fs_info->max_zone_append_size) > + can_merge = false; > + > if (prev_bio_flags != bio_flags || !contig || !can_merge || > force_bio_submit || > bio_add_page(bio, page, page_size, pg_offset) < page_size) { For zoned devices you need to use bio_add_hw_page instead of so that all the hardware restrictions are applied. bio_add_hw_page asso gets the lenght limited passed as the last parameter so we won't need a separate check.
On Fri, Sep 11, 2020 at 03:17:19PM +0100, Christoph Hellwig wrote: >On Fri, Sep 11, 2020 at 09:32:39PM +0900, Naohiro Aota wrote: >> + if (fs_info->max_zone_append_size && >> + bio_op(bio) == REQ_OP_WRITE && >> + bio->bi_iter.bi_size + size > fs_info->max_zone_append_size) >> + can_merge = false; >> + >> if (prev_bio_flags != bio_flags || !contig || !can_merge || >> force_bio_submit || >> bio_add_page(bio, page, page_size, pg_offset) < page_size) { > >For zoned devices you need to use bio_add_hw_page instead of so that all >the hardware restrictions are applied. bio_add_hw_page asso gets the >lenght limited passed as the last parameter so we won't need a separate >check. I think we can't use it here. This bio is built for btrfs's logical space, so the corresponding request queue is not available here. Technically, we can use fs_devices->lateste_bdev. But considering this bio can map to multiple bios to multiple devices, limiting the size of this bio under the minimum queue_max_zone_appends_sectors() among devices is feasible.
On Sat, Sep 12, 2020 at 01:14:24PM +0900, Naohiro Aota wrote: > > For zoned devices you need to use bio_add_hw_page instead of so that all > > the hardware restrictions are applied. bio_add_hw_page asso gets the > > lenght limited passed as the last parameter so we won't need a separate > > check. > > I think we can't use it here. This bio is built for btrfs's logical space, > so the corresponding request queue is not available here. > > Technically, we can use fs_devices->lateste_bdev. But considering this bio > can map to multiple bios to multiple devices, limiting the size of this bio > under the minimum queue_max_zone_appends_sectors() among devices is > feasible. Well, how do you then ensure the bio actually fits all the other device limits as well? e.g. max segment size, no SG gaps policy, etc?
On Sat, Sep 12, 2020 at 06:30:56AM +0100, Christoph Hellwig wrote: >On Sat, Sep 12, 2020 at 01:14:24PM +0900, Naohiro Aota wrote: >> > For zoned devices you need to use bio_add_hw_page instead of so that all >> > the hardware restrictions are applied. bio_add_hw_page asso gets the >> > lenght limited passed as the last parameter so we won't need a separate >> > check. >> >> I think we can't use it here. This bio is built for btrfs's logical space, >> so the corresponding request queue is not available here. >> >> Technically, we can use fs_devices->lateste_bdev. But considering this bio >> can map to multiple bios to multiple devices, limiting the size of this bio >> under the minimum queue_max_zone_appends_sectors() among devices is >> feasible. > >Well, how do you then ensure the bio actually fits all the other >device limits as well? e.g. max segment size, no SG gaps policy, >etc? Yeah, that's problematic, and I realized we could not deal with all the restrictions in this manner. I'm reimplementing this patch basing on bio_add_hw_page(). Regards,
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 53bac37bc4ac..63cdf67e6885 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3041,6 +3041,7 @@ static int submit_extent_page(unsigned int opf, size_t page_size = min_t(size_t, size, PAGE_SIZE); sector_t sector = offset >> 9; struct extent_io_tree *tree = &BTRFS_I(page->mapping->host)->io_tree; + struct btrfs_fs_info *fs_info = tree->fs_info; ASSERT(bio_ret); @@ -3058,6 +3059,11 @@ static int submit_extent_page(unsigned int opf, if (btrfs_bio_fits_in_stripe(page, page_size, bio, bio_flags)) can_merge = false; + if (fs_info->max_zone_append_size && + bio_op(bio) == REQ_OP_WRITE && + bio->bi_iter.bi_size + size > fs_info->max_zone_append_size) + can_merge = false; + if (prev_bio_flags != bio_flags || !contig || !can_merge || force_bio_submit || bio_add_page(bio, page, page_size, pg_offset) < page_size) {
Zone append write command cannot exceed the max zone append size. This commit limits the page merging into a bio. Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> --- fs/btrfs/extent_io.c | 6 ++++++ 1 file changed, 6 insertions(+)