[PATCH 04/11] btrfs: make add_extent_changeset() only return errors or success

[fdmanana@kernel.org]

From: Filipe Manana <fdmanana@suse.com>

Currently add_extent_changeset() always returns the return value from its
call to ulist_add(), which can return an error, 0 or 1. There are no
callers that care about the difference between 0 and 1 and all except one
of them, check for negative values and ignore other values, but there is
another caller (btrfs_clear_extent_bit_changeset()) that must set its
'ret' variable to 0 after calling add_extent_changeset(), so that it
does not return an unexpected value of 1 to its caller.

So change add_extent_changeset() to only return errors or 0, avoiding
that caller (and any future callers) from having to deal with a return
value of 1.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/extent-io-tree.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/extent-io-tree.c b/fs/btrfs/extent-io-tree.c
index 93dca9199249..5972fe28716e 100644
--- a/fs/btrfs/extent-io-tree.c
+++ b/fs/btrfs/extent-io-tree.c
@@ -187,6 +187,8 @@ static int add_extent_changeset(struct extent_state *state, u32 bits,
 				 struct extent_changeset *changeset,
 				 int set)
 {
+	int ret;
+
 	if (!changeset)
 		return 0;
 	if (set && (state->state & bits) == bits)
@@ -195,7 +197,10 @@ static int add_extent_changeset(struct extent_state *state, u32 bits,
 		return 0;
 	changeset->bytes_changed += state->end - state->start + 1;
 
-	return ulist_add(&changeset->range_changed, state->start, state->end, GFP_ATOMIC);
+	ret = ulist_add(&changeset->range_changed, state->start, state->end, GFP_ATOMIC);
+	if (ret < 0)
+		return ret;
+	return 0;
 }
 
 static inline struct extent_state *next_state(struct extent_state *state)
@@ -745,7 +750,6 @@ int btrfs_clear_extent_bit_changeset(struct extent_io_tree *tree, u64 start, u64
 						     "add_extent_changeset", ret);
 				goto out;
 			}
-			ret = 0;
 
 			if (tree->owner == IO_TREE_INODE_IO)
 				btrfs_clear_delalloc_extent(tree->inode, state, bits);
-- 
2.47.2