drbd: Ensure that an epoch contains only requests of one kind

The assert in drbd_req.c:755 forces us to have only requests of
one kind in an epoch. The two kinds we distinguish here are:
local-only or mirrored.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 1061b9fff2b080bf898fcb7cc483aa71a055831f..34ee8e44a75145b1fb775672cfead3b530d56555 100644 (file)
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1261,9 +1261,14 @@ __drbd_set_state(struct drbd_conf *mdev, union drbd_state ns,
        if (os.conn < C_CONNECTED && ns.conn >= C_CONNECTED)
                drbd_resume_al(mdev);
 
-       if (os.conn == C_AHEAD && ns.conn != C_AHEAD)
+       /* Start a new epoch in case we start to mirror write requests */
+       if (!drbd_should_do_remote(os) && drbd_should_do_remote(ns))
                tl_forget(mdev);
 
+       /* Do not add local-only requests to an epoch with mirrored requests */
+       if (drbd_should_do_remote(os) && !drbd_should_do_remote(ns))
+               set_bit(CREATE_BARRIER, &mdev->flags);
+
        ascw = kmalloc(sizeof(*ascw), GFP_ATOMIC);
        if (ascw) {
                ascw->os = os;

diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 6f9d1bfcca58c176b8a25f171ba3a6a2ae24c1cd..336937a14d3fc5cd60354e036ee3f97ebd613aeb 100644 (file)
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -762,27 +762,6 @@ static int drbd_may_do_local_read(struct drbd_conf *mdev, sector_t sector, int s
        return 0 == drbd_bm_count_bits(mdev, sbnr, ebnr);
 }
 
-static bool drbd_should_do_remote(struct drbd_conf *mdev)
-{
-       union drbd_state s = mdev->state;
-
-       return s.pdsk == D_UP_TO_DATE ||
-               (s.pdsk >= D_INCONSISTENT &&
-                s.conn >= C_WF_BITMAP_T &&
-                s.conn < C_AHEAD);
-       /* Before proto 96 that was >= CONNECTED instead of >= C_WF_BITMAP_T.
-          That is equivalent since before 96 IO was frozen in the C_WF_BITMAP*
-          states. */
-}
-static bool drbd_should_send_oos(struct drbd_conf *mdev)
-{
-       union drbd_state s = mdev->state;
-
-       return s.conn == C_AHEAD || s.conn == C_WF_BITMAP_S;
-       /* pdsk = D_INCONSISTENT as a consequence. Protocol 96 check not necessary
-          since we enter state C_AHEAD only if proto >= 96 */
-}
-
 static int drbd_make_request_common(struct drbd_conf *mdev, struct bio *bio, unsigned long start_time)
 {
        const int rw = bio_rw(bio);
@@ -854,8 +833,8 @@ static int drbd_make_request_common(struct drbd_conf *mdev, struct bio *bio, uns
                drbd_al_begin_io(mdev, sector);
        }
 
-       remote = remote && drbd_should_do_remote(mdev);
-       send_oos = rw == WRITE && drbd_should_send_oos(mdev);
+       remote = remote && drbd_should_do_remote(mdev->state);
+       send_oos = rw == WRITE && drbd_should_send_oos(mdev->state);
        D_ASSERT(!(remote && send_oos));
 
        if (!(local || remote) && !is_susp(mdev->state)) {
@@ -896,8 +875,8 @@ allocate_barrier:
        }
 
        if (remote || send_oos) {
-               remote = drbd_should_do_remote(mdev);
-               send_oos = rw == WRITE && drbd_should_send_oos(mdev);
+               remote = drbd_should_do_remote(mdev->state);
+               send_oos = rw == WRITE && drbd_should_send_oos(mdev->state);
                D_ASSERT(!(remote && send_oos));
 
                if (!(remote || send_oos))

diff --git a/drivers/block/drbd/drbd_req.h b/drivers/block/drbd/drbd_req.h
index 077c47b1e9d7807d2c08adf2d1003af2104531a3..32c1f2a312667e54b27cc023d94b254bb9d4d12d 100644 (file)
--- a/drivers/block/drbd/drbd_req.h
+++ b/drivers/block/drbd/drbd_req.h
@@ -360,4 +360,22 @@ static inline int req_mod(struct drbd_request *req,
 
        return rv;
 }
+
+static inline bool drbd_should_do_remote(union drbd_state s)
+{
+       return s.pdsk == D_UP_TO_DATE ||
+               (s.pdsk >= D_INCONSISTENT &&
+                s.conn >= C_WF_BITMAP_T &&
+                s.conn < C_AHEAD);
+       /* Before proto 96 that was >= CONNECTED instead of >= C_WF_BITMAP_T.
+          That is equivalent since before 96 IO was frozen in the C_WF_BITMAP*
+          states. */
+}
+static inline bool drbd_should_send_oos(union drbd_state s)
+{
+       return s.conn == C_AHEAD || s.conn == C_WF_BITMAP_S;
+       /* pdsk = D_INCONSISTENT as a consequence. Protocol 96 check not necessary
+          since we enter state C_AHEAD only if proto >= 96 */
+}
+
 #endif