label_scan: get scan_size from config setting

5 files changed, 22 insertions, 14 deletions

diff --git a/lib/commands/toolcontext.h b/lib/commands/toolcontext.h
index 6180f9fd7..702cc1680 100644
--- a/lib/commands/toolcontext.h
+++ b/lib/commands/toolcontext.h
@@ -39,6 +39,7 @@ struct config_info {
 	int udev_rules;
 	int udev_sync;
 	int udev_fallback;
+	int scan_size_kb;
 	const char *msg_prefix;
 	const char *fmt_name;
 	uint64_t unit_factor;
diff --git a/lib/format_text/import.c b/lib/format_text/import.c
index 088207448..1a62ea3dd 100644
--- a/lib/format_text/import.c
+++ b/lib/format_text/import.c
@@ -56,7 +56,7 @@ int text_read_metadata_summary(const struct format_type *fmt,
 			/*
 			 * Needs data beyond the end of the async read buffer.
 			 * Will do a new synchronous read to get the data.
-			 * (ASYNC_SCAN_SIZE could also be made larger.)
+			 * (scan_size could also be made larger.)
 			 */
 			log_debug_metadata("async read buffer for %s too small %u for metadata offset %llu size %u",
 					   dev_name(dev), ld->buf_len, (unsigned long long)offset, size);
@@ -177,7 +177,7 @@ struct volume_group *text_read_metadata(struct format_instance *fid,
 			/*
 			 * Needs data beyond the end of the async read buffer.
 			 * Will do a new synchronous read to get the data.
-			 * (ASYNC_SCAN_SIZE could also be made larger.)
+			 * (scan_size could also be made larger.)
 			 */
 			log_debug_metadata("async read buffer for %s too small %u for metadata offset %llu size %u",
 					   dev_name(dev), ld->buf_len, (unsigned long long)offset, size);
diff --git a/lib/label/label.c b/lib/label/label.c
index ec0a313ba..99d2521a2 100644
--- a/lib/label/label.c
+++ b/lib/label/label.c
@@ -628,8 +628,7 @@ struct label_read_data *get_label_read_data(struct cmd_context *cmd, struct devi
  */
 static int _get_scan_size(struct cmd_context *cmd)
 {
-	/* FIXME: make this a config setting, default to a multiple of optimal_io_size? */
-	return ASYNC_SCAN_SIZE;
+	return cmd->current_settings.scan_size_kb * 1024;
 }
 
 /*
@@ -1023,7 +1022,7 @@ static int _label_scan_devs_async(struct cmd_context *cmd, struct dm_list *devs)
 	/*
 	 * Process devices that have finished reading label sectors.
 	 * Processing can include sync i/o to read metadata areas
-	 * beyond the ASYNC_SCAN_SIZE.
+	 * beyond the scan_size.
 	 *
 	 * FIXME: we shouldn't need to fully reprocess everything when rescanning.
 	 * lvmcache is already populated from the previous scan, and if nothing
diff --git a/lib/label/label.h b/lib/label/label.h
index 265477cf8..0f88511dd 100644
--- a/lib/label/label.h
+++ b/lib/label/label.h
@@ -29,14 +29,6 @@ struct labeller;
 
 void allow_reads_with_lvmetad(void);
 
-/*
- * This is the amount of data read from each device
- * at the start of label scan.  It's meant to be big
- * enough to cover all the headers and metadata that
- * need to be read during label scan for common cases.
- */
-#define ASYNC_SCAN_SIZE (128 * 1024)
-
 struct label_read_data {
 	struct dev_async_io *aio;
 	char *buf; /* points to aio->buf */
diff --git a/tools/lvmcmdline.c b/tools/lvmcmdline.c
index a2e329dac..479453543 100644
--- a/tools/lvmcmdline.c
+++ b/tools/lvmcmdline.c
@@ -2266,6 +2266,7 @@ static void _apply_current_output_settings(struct cmd_context *cmd)
 static int _get_current_settings(struct cmd_context *cmd)
 {
 	const char *activation_mode;
+	int scan_size;
 
 	_get_current_output_settings_from_args(cmd);
 
@@ -2391,8 +2392,23 @@ static int _get_current_settings(struct cmd_context *cmd)
 #else
 	cmd->use_aio = 0;
 	if (find_config_tree_bool(cmd, metadata_scan_async_CFG, NULL))
-		log_verbose("No async I/O support, ignoring metadata/scan_async.");
+		log_verbose("Ignoring scan_async, no async I/O support.");
 #endif
+	scan_size = find_config_tree_int(cmd, metadata_scan_size_CFG, NULL);
+
+	if (!scan_size || (scan_size < 0)) {
+		log_warn("WARNING: Ignoring invalid metadata/scan_size %d, using default %u.",
+			 scan_size, DEFAULT_SCAN_SIZE_KB);
+		scan_size = DEFAULT_SCAN_SIZE_KB;
+	}
+
+	if (cmd->use_aio && (scan_size % 4)) {
+		log_warn("WARNING: Ignoring invalid metadata/scan_size %d with scan_async, using default %u.",
+			 scan_size, DEFAULT_SCAN_SIZE_KB);
+		scan_size = DEFAULT_SCAN_SIZE_KB;
+	}
+
+	cmd->current_settings.scan_size_kb = scan_size;
 
 	/* Zero indicates success */
 	return 0;