From 9b6135dca445fa300e8a1da5ed6ee84ab49c4945 Mon Sep 17 00:00:00 2001
From: Alasdair Kergon <agk@redhat.com>
Date: Wed, 5 Dec 2007 19:24:32 +0000
Subject: [PATCH] round readahead to multiple of page size in tools

---
 lib/activate/dev_manager.c |  4 ++--
 tools/lvchange.c           |  8 ++++++++
 tools/lvcreate.c           | 12 +++++++++++-
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/lib/activate/dev_manager.c b/lib/activate/dev_manager.c
index e4fd8c479..4c2d2c09f 100644
--- a/lib/activate/dev_manager.c
+++ b/lib/activate/dev_manager.c
@@ -952,10 +952,10 @@ static int _add_new_lv_to_dtree(struct dev_manager *dm, struct dm_tree *dtree,
 			max_stripe_size = seg->stripe_size;
 	}
 
-	if (read_ahead == DM_READ_AHEAD_AUTO)
+	if (read_ahead == DM_READ_AHEAD_AUTO) {
 		read_ahead = max_stripe_size;
-	else
 		read_ahead_flags = DM_READ_AHEAD_MINIMUM_FLAG;
+	}
 
 	dm_tree_node_set_read_ahead(dnode, read_ahead, read_ahead_flags);
 
diff --git a/tools/lvchange.c b/tools/lvchange.c
index 8f7f2423a..b5075d99b 100644
--- a/tools/lvchange.c
+++ b/tools/lvchange.c
@@ -372,6 +372,7 @@ static int lvchange_readahead(struct cmd_context *cmd,
 			      struct logical_volume *lv)
 {
 	unsigned read_ahead = 0;
+	unsigned pagesize = (unsigned) lvm_getpagesize() >> SECTOR_SHIFT;
 
 	read_ahead = arg_uint_value(cmd, readahead_ARG, 0);
 
@@ -382,6 +383,13 @@ static int lvchange_readahead(struct cmd_context *cmd,
 		return 0;
 	}
 
+	if (read_ahead != DM_READ_AHEAD_AUTO &&
+	    read_ahead != DM_READ_AHEAD_NONE && read_ahead % pagesize) {
+		read_ahead = (read_ahead / pagesize) * pagesize;
+		log_verbose("Rounding down readahead to %u sectors, a multiple "
+			    "of page size %u.", read_ahead, pagesize);
+	}
+
 	if (lv->read_ahead == read_ahead) {
 		log_error("Read ahead is already %u for \"%s\"",
 			  read_ahead, lv->name);
diff --git a/tools/lvcreate.c b/tools/lvcreate.c
index 241197ef6..958caa6b9 100644
--- a/tools/lvcreate.c
+++ b/tools/lvcreate.c
@@ -333,6 +333,7 @@ static int _lvcreate_params(struct lvcreate_params *lp, struct cmd_context *cmd,
 			    int argc, char **argv)
 {
 	int contiguous;
+	unsigned pagesize;
 
 	memset(lp, 0, sizeof(*lp));
 
@@ -462,8 +463,17 @@ static int _lvcreate_params(struct lvcreate_params *lp, struct cmd_context *cmd,
 	/*
 	 * Read ahead.
 	 */
-	if (arg_count(cmd, readahead_ARG))
+	if (arg_count(cmd, readahead_ARG)) {
 		lp->read_ahead = arg_uint_value(cmd, readahead_ARG, 0);
+		pagesize = lvm_getpagesize() >> SECTOR_SHIFT;
+		if (lp->read_ahead != DM_READ_AHEAD_AUTO &&
+		    lp->read_ahead != DM_READ_AHEAD_NONE &&
+		    lp->read_ahead % pagesize) {
+			lp->read_ahead = (lp->read_ahead / pagesize) * pagesize;
+			log_verbose("Rounding down readahead to %u sectors, a multiple "
+				    "of page size %u.", lp->read_ahead, pagesize);
+		}
+	}
 
 	/*
 	 * Permissions.