btrfs: mark extent buffer alignment checks as unlikely

We are not expecting to ever fail the extent buffer alignment checks, so
mark them as unlikely to allow the compiler to potentially generate more
optimized code.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Author: fdmanana

fs/btrfs/extent_io.c

@@ -3228,25 +3228,25 @@ static bool check_eb_alignment(struct btrfs_fs_info *fs_info, u64 start)
 {
 	const u32 nodesize = fs_info->nodesize;
 
-	if (!IS_ALIGNED(start, fs_info->sectorsize)) {
+	if (unlikely(!IS_ALIGNED(start, fs_info->sectorsize))) {
 		btrfs_err(fs_info, "bad tree block start %llu", start);
 		return true;
 	}
 
-	if (nodesize < PAGE_SIZE && !IS_ALIGNED(start, nodesize)) {
+	if (unlikely(nodesize < PAGE_SIZE && !IS_ALIGNED(start, nodesize))) {
 		btrfs_err(fs_info,
 		"tree block is not nodesize aligned, start %llu nodesize %u",
 			  start, nodesize);
 		return true;
 	}
-	if (nodesize >= PAGE_SIZE && !PAGE_ALIGNED(start)) {
+	if (unlikely(nodesize >= PAGE_SIZE && !PAGE_ALIGNED(start))) {
 		btrfs_err(fs_info,
 		"tree block is not page aligned, start %llu nodesize %u",
 			  start, nodesize);
 		return true;
 	}
-	if (!IS_ALIGNED(start, nodesize) &&
-	    !test_and_set_bit(BTRFS_FS_UNALIGNED_TREE_BLOCK, &fs_info->flags)) {
+	if (unlikely(!IS_ALIGNED(start, nodesize) &&
+		     !test_and_set_bit(BTRFS_FS_UNALIGNED_TREE_BLOCK, &fs_info->flags))) {
 		btrfs_warn(fs_info,
 "tree block not nodesize aligned, start %llu nodesize %u, can be resolved by a full metadata balance",
 			      start, nodesize);