Btrfs: self-tests: Execute page straddling test only when nodesize < PAGE_SIZE

On ppc64, PAGE_SIZE is 64k which is same as BTRFS_MAX_METADATA_BLOCKSIZE.
In such a scenario, we will never be able to have an extent buffer
containing more than one page. Hence in such cases this commit does not
execute the page straddling tests.
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Feifei Xu <xufeifei@linux.vnet.ibm.com>
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/tests/extent-io-tests.c

@@ -21,6 +21,7 @@
 #include <linux/slab.h>
 #include <linux/sizes.h>
 #include "btrfs-tests.h"
+#include "../ctree.h"
 #include "../extent_io.h"
 
 #define PROCESS_UNLOCK		(1 << 0)
@@ -298,7 +299,10 @@ static int __test_eb_bitmaps(unsigned long *bitmap, struct extent_buffer *eb,
 		return -EINVAL;
 	}
 
-	bitmap_set(bitmap, (PAGE_SIZE - sizeof(long) / 2) * BITS_PER_BYTE,
+	/* Straddling pages test */
+	if (len > PAGE_SIZE) {
+		bitmap_set(bitmap,
+			(PAGE_SIZE - sizeof(long) / 2) * BITS_PER_BYTE,
 			sizeof(long) * BITS_PER_BYTE);
 		extent_buffer_bitmap_set(eb, PAGE_SIZE - sizeof(long) / 2, 0,
 					sizeof(long) * BITS_PER_BYTE);
@@ -318,6 +322,7 @@ static int __test_eb_bitmaps(unsigned long *bitmap, struct extent_buffer *eb,
 			test_msg("Clearing straddling pages failed\n");
 			return -EINVAL;
 		}
+	}
 
 	/*
 	 * Generate a wonky pseudo-random bit pattern for the sake of not using
@@ -359,7 +364,13 @@ static int test_eb_bitmaps(u32 sectorsize, u32 nodesize)
 	int ret;
 
 	test_msg("Running extent buffer bitmap tests\n");
-	len = sectorsize * 4;
+
+	/*
+	 * In ppc64, sectorsize can be 64K, thus 4 * 64K will be larger than
+	 * BTRFS_MAX_METADATA_BLOCKSIZE.
+	 */
+	len = (sectorsize < BTRFS_MAX_METADATA_BLOCKSIZE)
+		? sectorsize * 4 : sectorsize;
 
 	bitmap = kmalloc(len, GFP_KERNEL);
 	if (!bitmap) {