drbd: Fixed w_restart_disk_io() to handle non active AL-extents

Since we now apply the AL in user space onto the bitmap, the AL
is not active for the requests we want to reply.

For that a al_write_transaction() that might be called from
worker context became necessary.

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_actlog.c b/drivers/block/drbd/drbd_actlog.c
index da8ffd5..5731d60 100644 (file)
--- a/drivers/block/drbd/drbd_actlog.c
+++ b/drivers/block/drbd/drbd_actlog.c
@@ -112,7 +112,7 @@ struct drbd_atodb_wait {
 };
 
 
-static int w_al_write_transaction(struct drbd_work *, int);
+static int al_write_transaction(struct drbd_conf *mdev);
 
 void *drbd_md_get_buffer(struct drbd_conf *mdev)
 {
@@ -272,18 +272,13 @@ void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i)
                /* Double check: it may have been committed by someone else,
                 * while we have been waiting for the lock. */
                if (mdev->act_log->pending_changes) {
-                       struct update_al_work al_work;
-                       init_completion(&al_work.event);
-                       al_work.w.cb = w_al_write_transaction;
-                       al_work.w.mdev = mdev;
-                       drbd_queue_work_front(&mdev->tconn->data.work, &al_work.w);
-                       wait_for_completion(&al_work.event);
-
+                       int err;
+                       err = al_write_transaction(mdev);
                        mdev->al_writ_cnt++;
 
                        spin_lock_irq(&mdev->al_lock);
                        /* FIXME
-                       if (al_work.err)
+                       if (err)
                                we need an "lc_cancel" here;
                        */
                        lc_committed(mdev->act_log);
@@ -348,23 +343,20 @@ static unsigned int rs_extent_to_bm_page(unsigned int rs_enr)
 }
 
 static int
-w_al_write_transaction(struct drbd_work *w, int unused)
+_al_write_transaction(struct drbd_conf *mdev)
 {
-       struct update_al_work *aw = container_of(w, struct update_al_work, w);
-       struct drbd_conf *mdev = w->mdev;
        struct al_transaction_on_disk *buffer;
        struct lc_element *e;
        sector_t sector;
        int i, mx;
        unsigned extent_nr;
        unsigned crc = 0;
+       int err = 0;
 
        if (!get_ldev(mdev)) {
                dev_err(DEV, "disk is %s, cannot start al transaction\n",
                        drbd_disk_str(mdev->state.disk));
-               aw->err = -EIO;
-               complete(&((struct update_al_work *)w)->event);
-               return 0;
+               return -EIO;
        }
 
        /* The bitmap write may have failed, causing a state change. */
@@ -372,19 +364,15 @@ w_al_write_transaction(struct drbd_work *w, int unused)
                dev_err(DEV,
                        "disk is %s, cannot write al transaction\n",
                        drbd_disk_str(mdev->state.disk));
-               aw->err = -EIO;
-               complete(&((struct update_al_work *)w)->event);
                put_ldev(mdev);
-               return 0;
+               return -EIO;
        }
 
        buffer = drbd_md_get_buffer(mdev); /* protects md_io_buffer, al_tr_cycle, ... */
        if (!buffer) {
                dev_err(DEV, "disk failed while waiting for md_io buffer\n");
-               aw->err = -EIO;
-               complete(&((struct update_al_work *)w)->event);
                put_ldev(mdev);
-               return 1;
+               return -ENODEV;
        }
 
        memset(buffer, 0, sizeof(*buffer));
@@ -444,10 +432,10 @@ w_al_write_transaction(struct drbd_work *w, int unused)
        buffer->crc32c = cpu_to_be32(crc);
 
        if (drbd_bm_write_hinted(mdev))
-               aw->err = -EIO;
+               err = -EIO;
                /* drbd_chk_io_error done already */
        else if (drbd_md_sync_page_io(mdev, mdev->ldev, sector, WRITE)) {
-               aw->err = -EIO;
+               err = -EIO;
                drbd_chk_io_error(mdev, 1, true);
        } else {
                /* advance ringbuffer position and transaction counter */
@@ -456,10 +444,42 @@ w_al_write_transaction(struct drbd_work *w, int unused)
        }
 
        drbd_md_put_buffer(mdev);
-       complete(&((struct update_al_work *)w)->event);
        put_ldev(mdev);
 
-       return 0;
+       return err;
+}
+
+
+static int w_al_write_transaction(struct drbd_work *w, int unused)
+{
+       struct update_al_work *aw = container_of(w, struct update_al_work, w);
+       struct drbd_conf *mdev = w->mdev;
+       int err;
+
+       err = _al_write_transaction(mdev);
+       aw->err = err;
+       complete(&aw->event);
+
+       return err != -EIO ? err : 0;
+}
+
+/* Calls from worker context (see w_restart_disk_io()) need to write the
+   transaction directly. Others came through generic_make_request(),
+   those need to delegate it to the worker. */
+static int al_write_transaction(struct drbd_conf *mdev)
+{
+       struct update_al_work al_work;
+
+       if (current == mdev->tconn->worker.task)
+               return _al_write_transaction(mdev);
+
+       init_completion(&al_work.event);
+       al_work.w.cb = w_al_write_transaction;
+       al_work.w.mdev = mdev;
+       drbd_queue_work_front(&mdev->tconn->data.work, &al_work.w);
+       wait_for_completion(&al_work.event);
+
+       return al_work.err;
 }
 
 static int _try_lc_del(struct drbd_conf *mdev, struct lc_element *al_ext)

diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 9ee9b9f..c57e47c 100644 (file)
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -1333,10 +1333,6 @@ int w_restart_disk_io(struct drbd_work *w, int cancel)
 
        if (bio_data_dir(req->master_bio) == WRITE && req->rq_state & RQ_IN_ACT_LOG)
                drbd_al_begin_io(mdev, &req->i);
-       /* Calling drbd_al_begin_io() out of the worker might deadlocks
-          theoretically. Practically it can not deadlock, since this is
-          only used when unfreezing IOs. All the extents of the requests
-          that made it into the TL are already active */
 
        drbd_req_make_private_bio(req, req->master_bio);
        req->private_bio->bi_bdev = mdev->ldev->backing_bdev;