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authorSerapheim Dimitropoulos <[email protected]>2019-01-18 11:10:32 -0800
committerBrian Behlendorf <[email protected]>2019-01-18 11:10:32 -0800
commitb194fab0fb6caad18711abccaff3c69ad8b3f6d3 (patch)
tree7f8d8d3507dc910b505d442921b826f30b1e3e66
parent960347d3a684a0063614eb293950f8f8c7dce7e1 (diff)
Factor metaslab_load_wait() in metaslab_load()
Most callers that need to operate on a loaded metaslab, always call metaslab_load_wait() before loading the metaslab just in case someone else is already doing the work. Factoring metaslab_load_wait() within metaslab_load() makes the later more robust, as callers won't have to do the load-wait check explicitly every time they need to load a metaslab. Reviewed-by: Matt Ahrens <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Serapheim Dimitropoulos <[email protected]> Closes #8290
-rw-r--r--cmd/zdb/zdb.c7
-rw-r--r--include/sys/metaslab.h1
-rw-r--r--include/sys/metaslab_impl.h4
-rw-r--r--module/zfs/metaslab.c82
-rw-r--r--module/zfs/vdev_initialize.c14
5 files changed, 53 insertions, 55 deletions
diff --git a/cmd/zdb/zdb.c b/cmd/zdb/zdb.c
index c436139a2..869b7a07f 100644
--- a/cmd/zdb/zdb.c
+++ b/cmd/zdb/zdb.c
@@ -910,11 +910,8 @@ dump_metaslab(metaslab_t *msp)
if (dump_opt['m'] > 2 && !dump_opt['L']) {
mutex_enter(&msp->ms_lock);
- metaslab_load_wait(msp);
- if (!msp->ms_loaded) {
- VERIFY0(metaslab_load(msp));
- range_tree_stat_verify(msp->ms_allocatable);
- }
+ VERIFY0(metaslab_load(msp));
+ range_tree_stat_verify(msp->ms_allocatable);
dump_metaslab_stats(msp);
metaslab_unload(msp);
mutex_exit(&msp->ms_lock);
diff --git a/include/sys/metaslab.h b/include/sys/metaslab.h
index fca233a38..f47bc19cf 100644
--- a/include/sys/metaslab.h
+++ b/include/sys/metaslab.h
@@ -49,7 +49,6 @@ int metaslab_init(metaslab_group_t *, uint64_t, uint64_t, uint64_t,
metaslab_t **);
void metaslab_fini(metaslab_t *);
-void metaslab_load_wait(metaslab_t *);
int metaslab_load(metaslab_t *);
void metaslab_unload(metaslab_t *);
diff --git a/include/sys/metaslab_impl.h b/include/sys/metaslab_impl.h
index 3e32eace6..137a84769 100644
--- a/include/sys/metaslab_impl.h
+++ b/include/sys/metaslab_impl.h
@@ -369,8 +369,8 @@ struct metaslab {
uint64_t ms_initializing; /* leaves initializing this ms */
/*
- * We must hold both ms_lock and ms_group->mg_lock in order to
- * modify ms_loaded.
+ * We must always hold the ms_lock when modifying ms_loaded
+ * and ms_loading.
*/
boolean_t ms_loaded;
boolean_t ms_loading;
diff --git a/module/zfs/metaslab.c b/module/zfs/metaslab.c
index 71688b420..20e7f0ed3 100644
--- a/module/zfs/metaslab.c
+++ b/module/zfs/metaslab.c
@@ -1402,7 +1402,7 @@ metaslab_ops_t *zfs_metaslab_ops = &metaslab_ndf_ops;
/*
* Wait for any in-progress metaslab loads to complete.
*/
-void
+static void
metaslab_load_wait(metaslab_t *msp)
{
ASSERT(MUTEX_HELD(&msp->ms_lock));
@@ -1413,20 +1413,17 @@ metaslab_load_wait(metaslab_t *msp)
}
}
-int
-metaslab_load(metaslab_t *msp)
+static int
+metaslab_load_impl(metaslab_t *msp)
{
int error = 0;
- boolean_t success = B_FALSE;
ASSERT(MUTEX_HELD(&msp->ms_lock));
- ASSERT(!msp->ms_loaded);
- ASSERT(!msp->ms_loading);
+ ASSERT(msp->ms_loading);
- msp->ms_loading = B_TRUE;
/*
* Nobody else can manipulate a loading metaslab, so it's now safe
- * to drop the lock. This way we don't have to hold the lock while
+ * to drop the lock. This way we don't have to hold the lock while
* reading the spacemap from disk.
*/
mutex_exit(&msp->ms_lock);
@@ -1443,29 +1440,49 @@ metaslab_load(metaslab_t *msp)
msp->ms_start, msp->ms_size);
}
- success = (error == 0);
-
mutex_enter(&msp->ms_lock);
- msp->ms_loading = B_FALSE;
- if (success) {
- ASSERT3P(msp->ms_group, !=, NULL);
- msp->ms_loaded = B_TRUE;
+ if (error != 0)
+ return (error);
- /*
- * If the metaslab already has a spacemap, then we need to
- * remove all segments from the defer tree; otherwise, the
- * metaslab is completely empty and we can skip this.
- */
- if (msp->ms_sm != NULL) {
- for (int t = 0; t < TXG_DEFER_SIZE; t++) {
- range_tree_walk(msp->ms_defer[t],
- range_tree_remove, msp->ms_allocatable);
- }
+ ASSERT3P(msp->ms_group, !=, NULL);
+ msp->ms_loaded = B_TRUE;
+
+ /*
+ * If the metaslab already has a spacemap, then we need to
+ * remove all segments from the defer tree; otherwise, the
+ * metaslab is completely empty and we can skip this.
+ */
+ if (msp->ms_sm != NULL) {
+ for (int t = 0; t < TXG_DEFER_SIZE; t++) {
+ range_tree_walk(msp->ms_defer[t],
+ range_tree_remove, msp->ms_allocatable);
}
- msp->ms_max_size = metaslab_block_maxsize(msp);
}
+ msp->ms_max_size = metaslab_block_maxsize(msp);
+
+ return (0);
+}
+
+int
+metaslab_load(metaslab_t *msp)
+{
+ ASSERT(MUTEX_HELD(&msp->ms_lock));
+
+ /*
+ * There may be another thread loading the same metaslab, if that's
+ * the case just wait until the other thread is done and return.
+ */
+ metaslab_load_wait(msp);
+ if (msp->ms_loaded)
+ return (0);
+ VERIFY(!msp->ms_loading);
+
+ msp->ms_loading = B_TRUE;
+ int error = metaslab_load_impl(msp);
+ msp->ms_loading = B_FALSE;
cv_broadcast(&msp->ms_load_cv);
+
return (error);
}
@@ -2041,13 +2058,10 @@ metaslab_activate(metaslab_t *msp, int allocator, uint64_t activation_weight)
ASSERT(MUTEX_HELD(&msp->ms_lock));
if ((msp->ms_weight & METASLAB_ACTIVE_MASK) == 0) {
- int error = 0;
- metaslab_load_wait(msp);
- if (!msp->ms_loaded) {
- if ((error = metaslab_load(msp)) != 0) {
- metaslab_group_sort(msp->ms_group, msp, 0);
- return (error);
- }
+ int error = metaslab_load(msp);
+ if (error != 0) {
+ metaslab_group_sort(msp->ms_group, msp, 0);
+ return (error);
}
if ((msp->ms_weight & METASLAB_ACTIVE_MASK) != 0) {
/*
@@ -2161,9 +2175,7 @@ metaslab_preload(void *arg)
ASSERT(!MUTEX_HELD(&msp->ms_group->mg_lock));
mutex_enter(&msp->ms_lock);
- metaslab_load_wait(msp);
- if (!msp->ms_loaded)
- (void) metaslab_load(msp);
+ (void) metaslab_load(msp);
msp->ms_selected_txg = spa_syncing_txg(spa);
mutex_exit(&msp->ms_lock);
spl_fstrans_unmark(cookie);
diff --git a/module/zfs/vdev_initialize.c b/module/zfs/vdev_initialize.c
index 939a5e938..e68f23e3f 100644
--- a/module/zfs/vdev_initialize.c
+++ b/module/zfs/vdev_initialize.c
@@ -363,16 +363,6 @@ vdev_initialize_ranges(vdev_t *vd, abd_t *data)
}
static void
-vdev_initialize_ms_load(metaslab_t *msp)
-{
- ASSERT(MUTEX_HELD(&msp->ms_lock));
-
- metaslab_load_wait(msp);
- if (!msp->ms_loaded)
- VERIFY0(metaslab_load(msp));
-}
-
-static void
vdev_initialize_mg_wait(metaslab_group_t *mg)
{
ASSERT(MUTEX_HELD(&mg->mg_ms_initialize_lock));
@@ -494,7 +484,7 @@ vdev_initialize_calculate_progress(vdev_t *vd)
* metaslab. Load it and walk the free tree for more accurate
* progress estimation.
*/
- vdev_initialize_ms_load(msp);
+ VERIFY0(metaslab_load(msp));
for (range_seg_t *rs = avl_first(&msp->ms_allocatable->rt_root);
rs; rs = AVL_NEXT(&msp->ms_allocatable->rt_root, rs)) {
@@ -630,7 +620,7 @@ vdev_initialize_thread(void *arg)
vdev_initialize_ms_mark(msp);
mutex_enter(&msp->ms_lock);
- vdev_initialize_ms_load(msp);
+ VERIFY0(metaslab_load(msp));
range_tree_walk(msp->ms_allocatable, vdev_initialize_range_add,
vd);