From: Joel Becker <Joel.Becker@oracle.com>
Date: Fri, 17 Mar 2006 01:40:37 +0000 (-0800)
Subject: [PATCH] ocfs2: Alloc at least a page for the DLM hash
X-Git-Tag: v2.6.18-rc1~594^2~50
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c8f33b6e86af74ee7b800f57cac7b3c8559318fe;p=linux-2.6

[PATCH] ocfs2: Alloc at least a page for the DLM hash

The OCFS2 DLM allocates a number of pages for a hash to lookup locks.
There was a bug where a PAGE_SIZE bigger than the hash size (eg, 64K
pages) would result in zero pages allocated.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
---

diff --git a/fs/ocfs2/dlm/dlmcommon.h b/fs/ocfs2/dlm/dlmcommon.h
index 0378ddbc8a..4fc1be3a3f 100644
--- a/fs/ocfs2/dlm/dlmcommon.h
+++ b/fs/ocfs2/dlm/dlmcommon.h
@@ -37,8 +37,12 @@
 #define DLM_THREAD_SHUFFLE_INTERVAL    5     // flush everything every 5 passes
 #define DLM_THREAD_MS                  200   // flush at least every 200 ms
 
-#define DLM_HASH_SIZE		(1 << 14)
-#define DLM_HASH_PAGES		(DLM_HASH_SIZE / PAGE_SIZE)
+#define DLM_HASH_SIZE_DEFAULT	(1 << 14)
+#if DLM_HASH_SIZE_DEFAULT < PAGE_SIZE
+# define DLM_HASH_PAGES		1
+#else
+# define DLM_HASH_PAGES		(DLM_HASH_SIZE_DEFAULT / PAGE_SIZE)
+#endif
 #define DLM_BUCKETS_PER_PAGE	(PAGE_SIZE / sizeof(struct hlist_head))
 #define DLM_HASH_BUCKETS	(DLM_HASH_PAGES * DLM_BUCKETS_PER_PAGE)
 
diff --git a/fs/ocfs2/dlm/dlmdomain.c b/fs/ocfs2/dlm/dlmdomain.c
index 80b8cce9cf..a074ec6f19 100644
--- a/fs/ocfs2/dlm/dlmdomain.c
+++ b/fs/ocfs2/dlm/dlmdomain.c
@@ -67,6 +67,9 @@ static void **dlm_alloc_pagevec(int pages)
 	for (i = 0; i < pages; i++)
 		if (!(vec[i] = (void *)__get_free_page(GFP_KERNEL)))
 			goto out_free;
+
+	mlog(0, "Allocated DLM hash pagevec; %d pages (%lu expected), %Zd buckets per page\n",
+	     pages, DLM_HASH_PAGES, DLM_BUCKETS_PER_PAGE);
 	return vec;
 out_free:
 	dlm_free_pagevec(vec, i);