From: Andreas Gruenbacher agruenba@redhat.com
[ Upstream commit 20be493b787cd581c9fffad7fcd6bfbe6af1050c ]
Fix several issues in the previous gfs2_find_jhead fix: * When updating @blocks_submitted, @block refers to the first block block not submitted yet, not the last block submitted, so fix an off-by-one error. * We want to ensure that @blocks_submitted is far enough ahead of @blocks_read to guarantee that there is in-flight I/O. Otherwise, we'll eventually end up waiting for pages that haven't been submitted, yet. * It's much easier to compare the number of blocks added with the number of blocks submitted to limit the maximum bio size. * Even with bio chaining, we can keep adding blocks until we reach the maximum bio size, as long as we stop at a page boundary. This simplifies the logic.
Signed-off-by: Andreas Gruenbacher agruenba@redhat.com Reviewed-by: Bob Peterson rpeterso@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/gfs2/lops.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-)
diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c index 8303b44a5068..d2ed4dc4434c 100644 --- a/fs/gfs2/lops.c +++ b/fs/gfs2/lops.c @@ -504,12 +504,12 @@ int gfs2_find_jhead(struct gfs2_jdesc *jd, struct gfs2_log_header_host *head, unsigned int bsize = sdp->sd_sb.sb_bsize, off; unsigned int bsize_shift = sdp->sd_sb.sb_bsize_shift; unsigned int shift = PAGE_SHIFT - bsize_shift; - unsigned int max_bio_size = 2 * 1024 * 1024; + unsigned int max_blocks = 2 * 1024 * 1024 >> bsize_shift; struct gfs2_journal_extent *je; int sz, ret = 0; struct bio *bio = NULL; struct page *page = NULL; - bool bio_chained = false, done = false; + bool done = false; errseq_t since;
memset(head, 0, sizeof(*head)); @@ -532,10 +532,7 @@ int gfs2_find_jhead(struct gfs2_jdesc *jd, struct gfs2_log_header_host *head, off = 0; }
- if (!bio || (bio_chained && !off) || - bio->bi_iter.bi_size >= max_bio_size) { - /* start new bio */ - } else { + if (bio && (off || block < blocks_submitted + max_blocks)) { sector_t sector = dblock << sdp->sd_fsb2bb_shift;
if (bio_end_sector(bio) == sector) { @@ -548,19 +545,17 @@ int gfs2_find_jhead(struct gfs2_jdesc *jd, struct gfs2_log_header_host *head, (PAGE_SIZE - off) >> bsize_shift;
bio = gfs2_chain_bio(bio, blocks); - bio_chained = true; goto add_block_to_new_bio; } }
if (bio) { - blocks_submitted = block + 1; + blocks_submitted = block; submit_bio(bio); }
bio = gfs2_log_alloc_bio(sdp, dblock, gfs2_end_log_read); bio->bi_opf = REQ_OP_READ; - bio_chained = false; add_block_to_new_bio: sz = bio_add_page(bio, page, bsize, off); BUG_ON(sz != bsize); @@ -568,7 +563,7 @@ int gfs2_find_jhead(struct gfs2_jdesc *jd, struct gfs2_log_header_host *head, off += bsize; if (off == PAGE_SIZE) page = NULL; - if (blocks_submitted < 2 * max_bio_size >> bsize_shift) { + if (blocks_submitted <= blocks_read + max_blocks) { /* Keep at least one bio in flight */ continue; }