From b9b98716f83856b928f1c985ab55520c67663dd2 Mon Sep 17 00:00:00 2001 From: Philipp Reisner Date: Tue, 22 Jun 2010 11:26:48 +0200 Subject: [PATCH] drbd: Do not send two barriers without any writes between them Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg --- drivers/block/drbd/drbd_main.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c index a8a0341..7d35986 100644 --- a/drivers/block/drbd/drbd_main.c +++ b/drivers/block/drbd/drbd_main.c @@ -344,7 +344,7 @@ bail: static void _tl_restart(struct drbd_conf *mdev, enum drbd_req_event what) { struct drbd_tl_epoch *b, *tmp, **pn; - struct list_head *le, *tle; + struct list_head *le, *tle, carry_reads; struct drbd_request *req; int rv, n_writes, n_reads; @@ -353,6 +353,7 @@ static void _tl_restart(struct drbd_conf *mdev, enum drbd_req_event what) while (b) { n_writes = 0; n_reads = 0; + INIT_LIST_HEAD(&carry_reads); list_for_each_safe(le, tle, &b->requests) { req = list_entry(le, struct drbd_request, tl_requests); rv = _req_mod(req, what); @@ -362,7 +363,7 @@ static void _tl_restart(struct drbd_conf *mdev, enum drbd_req_event what) } tmp = b->next; - if (n_writes + n_reads) { + if (n_writes) { if (what == resend) { b->n_writes = n_writes; if (b->w.cb == NULL) { @@ -375,6 +376,8 @@ static void _tl_restart(struct drbd_conf *mdev, enum drbd_req_event what) } pn = &b->next; } else { + if (n_reads) + list_add(&carry_reads, &b->requests); /* there could still be requests on that ring list, * in case local io is still pending */ list_del(&b->requests); @@ -389,6 +392,7 @@ static void _tl_restart(struct drbd_conf *mdev, enum drbd_req_event what) /* recycle, but reinit! */ D_ASSERT(tmp == NULL); INIT_LIST_HEAD(&b->requests); + list_splice(&carry_reads, &b->requests); INIT_LIST_HEAD(&b->w.list); b->w.cb = NULL; b->br_number = net_random(); @@ -401,6 +405,7 @@ static void _tl_restart(struct drbd_conf *mdev, enum drbd_req_event what) kfree(b); } b = tmp; + list_splice(&carry_reads, &b->requests); } } -- 2.7.4