Illumos 5056 - ZFS deadlock on db_mtx and dn_holds

[mirror_zfs.git] / module / zfs / dsl_dir.c

diff --git a/module/zfs/dsl_dir.c b/module/zfs/dsl_dir.c
index 0a0a0fa7cd3e2282b8d46c0f47284222f652c971..e85cb81aec245f5cf201fda22969f6f22519b58a 100644 (file)
--- a/module/zfs/dsl_dir.c
+++ b/module/zfs/dsl_dir.c
@@ -23,6 +23,7 @@
  * Copyright (c) 2013 by Delphix. All rights reserved.
  * Copyright (c) 2013 Martin Matuska. All rights reserved.
  * Copyright (c) 2014 Joyent, Inc. All rights reserved.
+ * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
  */
 
 #include <sys/dmu.h>
@@ -126,14 +127,15 @@ extern inline dsl_dir_phys_t *dsl_dir_phys(dsl_dir_t *dd);
 
 static uint64_t dsl_dir_space_towrite(dsl_dir_t *dd);
 
-/* ARGSUSED */
 static void
-dsl_dir_evict(dmu_buf_t *db, void *arg)
+dsl_dir_evict(void *dbu)
 {
-       dsl_dir_t *dd = arg;
+       dsl_dir_t *dd = dbu;
        int t;
        ASSERTV(dsl_pool_t *dp = dd->dd_pool);
 
+       dd->dd_dbuf = NULL;
+
        for (t = 0; t < TXG_SIZE; t++) {
                ASSERT(!txg_list_member(&dp->dp_dirty_dirs, dd, t));
                ASSERT(dd->dd_tempreserved[t] == 0);
@@ -141,9 +143,9 @@ dsl_dir_evict(dmu_buf_t *db, void *arg)
        }
 
        if (dd->dd_parent)
-               dsl_dir_rele(dd->dd_parent, dd);
+               dsl_dir_async_rele(dd->dd_parent, dd);
 
-       spa_close(dd->dd_pool->dp_spa, dd);
+       spa_async_close(dd->dd_pool->dp_spa, dd);
 
        /*
         * The props callback list should have been cleaned up by
@@ -239,8 +241,9 @@ dsl_dir_hold_obj(dsl_pool_t *dp, uint64_t ddobj,
                        dmu_buf_rele(origin_bonus, FTAG);
                }
 
-               winner = dmu_buf_set_user_ie(dbuf, dd, dsl_dir_evict);
-               if (winner) {
+               dmu_buf_init_user(&dd->dd_dbu, dsl_dir_evict, &dd->dd_dbuf);
+               winner = dmu_buf_set_user_ie(dbuf, &dd->dd_dbu);
+               if (winner != NULL) {
                        if (dd->dd_parent)
                                dsl_dir_rele(dd->dd_parent, dd);
                        mutex_destroy(&dd->dd_lock);
@@ -284,6 +287,21 @@ dsl_dir_rele(dsl_dir_t *dd, void *tag)
        dmu_buf_rele(dd->dd_dbuf, tag);
 }
 
+/*
+ * Remove a reference to the given dsl dir that is being asynchronously
+ * released.  Async releases occur from a taskq performing eviction of
+ * dsl datasets and dirs.  This process is identical to a normal release
+ * with the exception of using the async API for releasing the reference on
+ * the spa.
+ */
+void
+dsl_dir_async_rele(dsl_dir_t *dd, void *tag)
+{
+       dprintf_dd(dd, "%s\n", "");
+       spa_async_close(dd->dd_pool->dp_spa, tag);
+       dmu_buf_rele(dd->dd_dbuf, tag);
+}
+
 /* buf must be long enough (MAXNAMELEN + strlen(MOS_DIR_NAME) + 1 should do) */
 void
 dsl_dir_name(dsl_dir_t *dd, char *buf)
@@ -417,7 +435,7 @@ dsl_dir_hold(dsl_pool_t *dp, const char *name, void *tag,
        }
 
        while (next != NULL) {
-               dsl_dir_t *child_ds;
+               dsl_dir_t *child_dd;
                err = getcomponent(next, buf, &nextnext);
                if (err != 0)
                        break;
@@ -436,11 +454,11 @@ dsl_dir_hold(dsl_pool_t *dp, const char *name, void *tag,
                        break;
                }
 
-               err = dsl_dir_hold_obj(dp, ddobj, buf, tag, &child_ds);
+               err = dsl_dir_hold_obj(dp, ddobj, buf, tag, &child_dd);
                if (err != 0)
                        break;
                dsl_dir_rele(dd, tag);
-               dd = child_ds;
+               dd = child_dd;
                next = nextnext;
        }