Btrfs: Change TestSetPageLocked() to trylock_page()

Add backwards compatibility in compat.h
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
---
 compat.h    |    3 +++
 extent_io.c |    3 ++-
 2 files changed, 5 insertions(+), 1 deletions(-)
Signed-off-by: Chris Mason <chris.mason@oracle.com>

fs/btrfs/compat.h

 #ifndef _COMPAT_H_
 #define _COMPAT_H_
 
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,26)
+#define trylock_page(page) (!TestSetPageLocked(page))
+#endif
 
 /*
  * Even if AppArmor isn't enabled, it still has different prototypes.

fs/btrfs/extent_io.c

@@ -14,6 +14,7 @@
 #include <linux/pagevec.h>
 #include "extent_io.h"
 #include "extent_map.h"
+#include "compat.h"
 
 /* temporary define until extent_map moves out of btrfs */
 struct kmem_cache *btrfs_cache_create(const char *name, size_t size,
@@ -3055,7 +3056,7 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
 	for (i = start_i; i < num_pages; i++) {
 		page = extent_buffer_page(eb, i);
 		if (!wait) {
-			if (TestSetPageLocked(page))
+			if (!trylock_page(page))
 				goto unlock_exit;
 		} else {
 			lock_page(page);