Btrfs: Add compatibility for kernels >= 2.6.27-rc1

Add a couple of #if's to follow API changes.
Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

fs/btrfs/extent_io.c

@@ -2649,9 +2649,24 @@ static inline struct page *extent_buffer_page(struct extent_buffer *eb,
 	mapping = eb->first_page->mapping;
 	if (!mapping)
 		return NULL;
+
+	/*
+	 * extent_buffer_page is only called after pinning the page
+	 * by increasing the reference count.  So we know the page must
+	 * be in the radix tree.
+	 */
+#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
+	rcu_read_lock();
+#else
 	read_lock_irq(&mapping->tree_lock);
+#endif
 	p = radix_tree_lookup(&mapping->page_tree, i);
+
+#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
+	rcu_read_unlock();
+#else
 	read_unlock_irq(&mapping->tree_lock);
+#endif
 	return p;
 }
 
@@ -2843,13 +2858,21 @@ int clear_extent_buffer_dirty(struct extent_io_tree *tree,
 			}
 		}
 		clear_page_dirty_for_io(page);
+#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
+		spin_lock_irq(&page->mapping->tree_lock);
+#else
 		read_lock_irq(&page->mapping->tree_lock);
+#endif
 		if (!PageDirty(page)) {
 			radix_tree_tag_clear(&page->mapping->page_tree,
 						page_index(page),
 						PAGECACHE_TAG_DIRTY);
 		}
+#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
+		spin_unlock_irq(&page->mapping->tree_lock);
+#else
 		read_unlock_irq(&page->mapping->tree_lock);
+#endif
 		unlock_page(page);
 	}
 	return 0;

fs/btrfs/file.c

@@ -886,7 +886,11 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
 #ifdef REMOVE_SUID_PATH
 	err = remove_suid(&file->f_path);
 #else
+# if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
+	err = file_remove_suid(file);
+# else
 	err = remove_suid(fdentry(file));
+# endif
 #endif
 	if (err)
 		goto out_nolock;

fs/btrfs/inode.c

@@ -3293,7 +3293,9 @@ void btrfs_destroy_inode(struct inode *inode)
 	kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
 }
 
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
+#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
+static void init_once(void *foo)
+#elif LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
 static void init_once(struct kmem_cache * cachep, void *foo)
 #else
 static void init_once(void * foo, struct kmem_cache * cachep,
@@ -3321,7 +3323,9 @@ void btrfs_destroy_cachep(void)
 
 struct kmem_cache *btrfs_cache_create(const char *name, size_t size,
 				       unsigned long extra_flags,
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
+#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
+				       void (*ctor)(void *)
+#elif LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
 				       void (*ctor)(struct kmem_cache *, void *)
 #else
 				       void (*ctor)(void *, struct kmem_cache *,
@@ -3561,8 +3565,12 @@ static int btrfs_set_page_dirty(struct page *page)
 	return __set_page_dirty_nobuffers(page);
 }
 
+#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
+static int btrfs_permission(struct inode *inode, int mask)
+#else
 static int btrfs_permission(struct inode *inode, int mask,
 			    struct nameidata *nd)
+#endif
 {
 	if (btrfs_test_flag(inode, READONLY) && (mask & MAY_WRITE))
 		return -EACCES;