Commit 7b62e66c authored Dec 11, 2019 by Dennis Zhou Committed by David Sterba Dec 30, 2019

btrfs: punt all bios created in btrfs_submit_compressed_write()



Compressed writes happen in the background via kworkers. However, this
causes bios to be attributed to root bypassing any cgroup limits from
the actual writer. We tag the first bio with REQ_CGROUP_PUNT, which will
punt the bio to an appropriate cgroup specific workqueue and attribute
the IO properly. However, if btrfs_submit_compressed_write() creates a
new bio, we don't tag it the same way. Add the appropriate tagging for
subsequent bios.

Fixes: ec39f769 ("Btrfs: use REQ_CGROUP_PUNT for worker thread submitted bios")
Reviewed-by: Chris Mason <clm@fb.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

parent fbd54297

fs/btrfs/compression.c

+4 −0

Original line number	Original line	Diff line number	Diff line
	@@ -491,6 +491,10 @@ blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start,
	bio->bi_opf = REQ_OP_WRITE \| write_flags;		bio->bi_opf = REQ_OP_WRITE \| write_flags;
	bio->bi_private = cb;		bio->bi_private = cb;
	bio->bi_end_io = end_compressed_bio_write;		bio->bi_end_io = end_compressed_bio_write;
			if (blkcg_css) {
			bio->bi_opf \|= REQ_CGROUP_PUNT;
			bio_associate_blkg_from_css(bio, blkcg_css);
			}
	bio_add_page(bio, page, PAGE_SIZE, 0);		bio_add_page(bio, page, PAGE_SIZE, 0);
	}		}
	if (bytes_left < PAGE_SIZE) {		if (bytes_left < PAGE_SIZE) {

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