Post-push fix for MDEV-12610 MariaDB start is slow

fil_crypt_read_crypt_data(): Remove an unnecessary
acquisition of fil_system->mutex. Remove a duplicated condition
from the callers.

2 files changed, 44 insertions, 84 deletions

diff --git a/storage/innobase/fil/fil0crypt.cc b/storage/innobase/fil/fil0crypt.cc
index 70d8558ede2..df5c250df90 100644
--- a/storage/innobase/fil/fil0crypt.cc
+++ b/storage/innobase/fil/fil0crypt.cc
@@ -1116,40 +1116,33 @@ fil_crypt_needs_rotation(
 }
 
 /** Read page 0 and possible crypt data from there.
-@param[in]	space		Tablespace */
+@param[in,out]	space		Tablespace */
 static inline
 void
 fil_crypt_read_crypt_data(fil_space_t* space)
 {
-	mutex_enter(&fil_system->mutex);
-
-	/* If space does not contain crypt data and space size is 0
-	we have not yet read first page of tablespace. We need to
-	read it to find out tablespace current encryption status. */
-	if (!space->crypt_data && space->size == 0) {
-		mtr_t	mtr;
-		mtr_start(&mtr);
-		ulint zip_size = fsp_flags_get_zip_size(space->flags);
-		ulint offset = fsp_header_get_crypt_offset(zip_size);
-		mutex_exit(&fil_system->mutex);
-		if (buf_block_t* block = buf_page_get(space->id, zip_size, 0,
-				RW_X_LATCH, &mtr)) {
-			byte* frame = buf_block_get_frame(block);
-
-			mutex_enter(&fil_system->mutex);
-
-			if (!space->crypt_data) {
-				space->crypt_data = fil_space_read_crypt_data(space->id,
-					frame, offset);
-			}
+	if (space->crypt_data || space->size) {
+		/* The encryption metadata has already been read, or
+		the tablespace is not encrypted and the file has been
+		opened already. */
+		return;
+	}
 
-			mutex_exit(&fil_system->mutex);
+	mtr_t	mtr;
+	mtr_start(&mtr);
+	ulint zip_size = fsp_flags_get_zip_size(space->flags);
+	ulint offset = fsp_header_get_crypt_offset(zip_size);
+	if (buf_block_t* block = buf_page_get(space->id, zip_size, 0,
+					      RW_S_LATCH, &mtr)) {
+		mutex_enter(&fil_system->mutex);
+		if (!space->crypt_data) {
+			space->crypt_data = fil_space_read_crypt_data(
+				space->id, block->frame, offset);
 		}
-
-		mtr_commit(&mtr);
-	} else {
 		mutex_exit(&fil_system->mutex);
 	}
+
+	mtr_commit(&mtr);
 }
 
 /***********************************************************************
@@ -1656,12 +1649,7 @@ fil_crypt_find_space_to_rotate(
 	}
 
 	while (!state->should_shutdown() && state->space) {
-		/* If there is no crypt data and we have not yet read
-		page 0 for this tablespace, we need to read it before
-		we can continue. */
-		if (!state->space->crypt_data) {
-			fil_crypt_read_crypt_data(state->space);
-		}
+		fil_crypt_read_crypt_data(state->space);
 
 		if (fil_crypt_space_needs_rotation(state, key_state, recheck)) {
 			ut_ad(key_state->key_id);
@@ -2589,18 +2577,10 @@ fil_space_crypt_get_status(
 	memset(status, 0, sizeof(*status));
 
 	ut_ad(space->n_pending_ops > 0);
-
-	/* If there is no crypt data and we have not yet read
-	page 0 for this tablespace, we need to read it before
-	we can continue. */
-	if (!space->crypt_data) {
-		fil_crypt_read_crypt_data(const_cast<fil_space_t*>(space));
-	}
-
-	fil_space_crypt_t* crypt_data = space->crypt_data;
+	fil_crypt_read_crypt_data(const_cast<fil_space_t*>(space));
 	status->space = space->id;
 
-	if (crypt_data != NULL) {
+	if (fil_space_crypt_t* crypt_data = space->crypt_data) {
 		mutex_enter(&crypt_data->mutex);
 		status->scheme = crypt_data->type;
 		status->keyserver_requests = crypt_data->keyserver_requests;
diff --git a/storage/xtradb/fil/fil0crypt.cc b/storage/xtradb/fil/fil0crypt.cc
index e24278dd102..6d3c2e98010 100644
--- a/storage/xtradb/fil/fil0crypt.cc
+++ b/storage/xtradb/fil/fil0crypt.cc
@@ -1116,40 +1116,33 @@ fil_crypt_needs_rotation(
 }
 
 /** Read page 0 and possible crypt data from there.
-@param[in]	space		Tablespace */
+@param[in,out]	space		Tablespace */
 static inline
 void
 fil_crypt_read_crypt_data(fil_space_t* space)
 {
-	mutex_enter(&fil_system->mutex);
-
-	/* If space does not contain crypt data and space size is 0
-	we have not yet read first page of tablespace. We need to
-	read it to find out tablespace current encryption status. */
-	if (!space->crypt_data && space->size == 0) {
-		mtr_t	mtr;
-		mtr_start(&mtr);
-		ulint zip_size = fsp_flags_get_zip_size(space->flags);
-		ulint offset = fsp_header_get_crypt_offset(zip_size);
-		mutex_exit(&fil_system->mutex);
-		if (buf_block_t* block = buf_page_get(space->id, zip_size, 0,
-				RW_X_LATCH, &mtr)) {
-			byte* frame = buf_block_get_frame(block);
-
-			mutex_enter(&fil_system->mutex);
-
-			if (!space->crypt_data) {
-				space->crypt_data = fil_space_read_crypt_data(space->id,
-					frame, offset);
-			}
+	if (space->crypt_data || space->size) {
+		/* The encryption metadata has already been read, or
+		the tablespace is not encrypted and the file has been
+		opened already. */
+		return;
+	}
 
-			mutex_exit(&fil_system->mutex);
+	mtr_t	mtr;
+	mtr_start(&mtr);
+	ulint zip_size = fsp_flags_get_zip_size(space->flags);
+	ulint offset = fsp_header_get_crypt_offset(zip_size);
+	if (buf_block_t* block = buf_page_get(space->id, zip_size, 0,
+					      RW_S_LATCH, &mtr)) {
+		mutex_enter(&fil_system->mutex);
+		if (!space->crypt_data) {
+			space->crypt_data = fil_space_read_crypt_data(
+				space->id, block->frame, offset);
 		}
-
-		mtr_commit(&mtr);
-	} else {
 		mutex_exit(&fil_system->mutex);
 	}
+
+	mtr_commit(&mtr);
 }
 
 /***********************************************************************
@@ -1656,12 +1649,7 @@ fil_crypt_find_space_to_rotate(
 	}
 
 	while (!state->should_shutdown() && state->space) {
-		/* If there is no crypt data and we have not yet read
-		page 0 for this tablespace, we need to read it before
-		we can continue. */
-		if (!state->space->crypt_data) {
-			fil_crypt_read_crypt_data(state->space);
-		}
+		fil_crypt_read_crypt_data(state->space);
 
 		if (fil_crypt_space_needs_rotation(state, key_state, recheck)) {
 			ut_ad(key_state->key_id);
@@ -2590,18 +2578,10 @@ fil_space_crypt_get_status(
 	memset(status, 0, sizeof(*status));
 
 	ut_ad(space->n_pending_ops > 0);
-
-	/* If there is no crypt data and we have not yet read
-	page 0 for this tablespace, we need to read it before
-	we can continue. */
-	if (!space->crypt_data) {
-		fil_crypt_read_crypt_data(const_cast<fil_space_t*>(space));
-	}
-
-	fil_space_crypt_t* crypt_data = space->crypt_data;
+	fil_crypt_read_crypt_data(const_cast<fil_space_t*>(space));
 	status->space = space->id;
 
-	if (crypt_data != NULL) {
+	if (fil_space_crypt_t* crypt_data = space->crypt_data) {
 		mutex_enter(&crypt_data->mutex);
 		status->scheme = crypt_data->type;
 		status->keyserver_requests = crypt_data->keyserver_requests;