Btrfs: Fix variables set but not read (bugs found by gcc 4.6)

These are all the cases where a variable is set, but not
read which are really bugs.

- Couple of incorrect error handling fixed.
- One incorrect use of a allocation policy
- Some other things

Still needs more review.

Found by gcc 4.6's new warnings.

[akpm@linux-foundation.org: fix build.  Might have been bitrot]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

5 files changed, 10 insertions, 6 deletions

diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
index e9103b3baa49..f0cad5ae5be7 100644
--- a/fs/btrfs/dir-item.c
+++ b/fs/btrfs/dir-item.c
@@ -427,5 +427,5 @@ int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
                 ret = btrfs_truncate_item(trans, root, path,
                                           item_len - sub_item_len, 1);
         }
-        return 0;
+        return ret;
 }
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 4c639e156296..7dc31c39ca59 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2779,6 +2779,8 @@ int extent_prepare_write(struct extent_io_tree *tree,
                                          NULL, 1,
                                          end_bio_extent_preparewrite, 0,
                                          0, 0);
+                        if (ret && !err)
+                                err = ret;
                         iocount++;
                         block_start = block_start + iosize;
                 } else {
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 9f08136b10c4..0aa24717cd58 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1389,7 +1389,7 @@ int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
 
         if (map_length < length + size)
                 return 1;
-        return 0;
+        return ret;
 }
 
 /*
@@ -2709,8 +2709,8 @@ static int check_path_shared(struct btrfs_root *root,
 {
         struct extent_buffer *eb;
         int level;
-        int ret;
         u64 refs = 1;
+        int uninitialized_var(ret);
 
         for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
                 if (!path->nodes[level])
@@ -2723,7 +2723,7 @@ static int check_path_shared(struct btrfs_root *root,
                 if (refs > 1)
                         return 1;
         }
-        return 0;
+        return ret; /* XXX callers? */
 }
 
 /*
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index fd0714475db7..045c9c2b2d7e 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -3094,6 +3094,8 @@ static int add_tree_block(struct reloc_control *rc,
                 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
                 ret = get_ref_objectid_v0(rc, path, extent_key,
                                           &ref_owner, NULL);
+                if (ret < 0)
+                        return ret;
                 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
                 level = (int)ref_owner;
                 /* FIXME: get real generation */
@@ -4218,7 +4220,7 @@ int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
                 btrfs_add_ordered_sum(inode, ordered, sums);
         }
         btrfs_put_ordered_extent(ordered);
-        return 0;
+        return ret;
 }
 
 void btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index fb102a9aee9c..224fb5b3daad 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2273,7 +2273,7 @@ fail:
         }
         btrfs_end_log_trans(root);
 
-        return 0;
+        return err;
 }
 
 /* see comments for btrfs_del_dir_entries_in_log */