fs: btrfs: Fix cache alignment bugs

The btrfs implementation passes cache-unaligned buffers into the
block layer, which triggers cache alignment problems down in the
block device drivers. Align the buffers to prevent this.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Marek Behun <marek.behun@nic.cz>

1 files changed, 13 insertions, 11 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 4da36a9bc7..18b47d92fe 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -7,6 +7,7 @@
 
 #include "btrfs.h"
 #include <malloc.h>
+#include <memalign.h>
 
 int btrfs_comp_keys(struct btrfs_key *a, struct btrfs_key *b)
 {
@@ -105,23 +106,24 @@ void btrfs_free_path(struct btrfs_path *p)
 
 static int read_tree_node(u64 physical, union btrfs_tree_node **buf)
 {
-	struct btrfs_header hdr;
-	unsigned long size, offset = sizeof(hdr);
+	ALLOC_CACHE_ALIGN_BUFFER(struct btrfs_header, hdr,
+				 sizeof(struct btrfs_header));
+	unsigned long size, offset = sizeof(*hdr);
 	union btrfs_tree_node *res;
 	u32 i;
 
-	if (!btrfs_devread(physical, sizeof(hdr), &hdr))
+	if (!btrfs_devread(physical, sizeof(*hdr), hdr))
 		return -1;
 
-	btrfs_header_to_cpu(&hdr);
+	btrfs_header_to_cpu(hdr);
 
-	if (hdr.level)
+	if (hdr->level)
 		size = sizeof(struct btrfs_node)
-		       + hdr.nritems * sizeof(struct btrfs_key_ptr);
+		       + hdr->nritems * sizeof(struct btrfs_key_ptr);
 	else
 		size = btrfs_info.sb.nodesize;
 
-	res = malloc(size);
+	res = malloc_cache_aligned(size);
 	if (!res) {
 		debug("%s: malloc failed\n", __func__);
 		return -1;
@@ -133,12 +135,12 @@ static int read_tree_node(u64 physical, union btrfs_tree_node **buf)
 		return -1;
 	}
 
-	res->header = hdr;
-	if (hdr.level)
-		for (i = 0; i < hdr.nritems; ++i)
+	memcpy(&res->header, hdr, sizeof(*hdr));
+	if (hdr->level)
+		for (i = 0; i < hdr->nritems; ++i)
 			btrfs_key_ptr_to_cpu(&res->node.ptrs[i]);
 	else
-		for (i = 0; i < hdr.nritems; ++i)
+		for (i = 0; i < hdr->nritems; ++i)
 			btrfs_item_to_cpu(&res->leaf.items[i]);
 
 	*buf = res;