btrfs: use a single switch statement when initializing delayed ref head

At init_delayed_ref_head(), we are using two separate if statements to
check the delayed ref head action, and initializing 'must_insert_reserved'
to false twice, once when the variable is declared and once again in an
else branch.

Make this simpler and more straightforward by having a single switch
statement, also moving the comment about a drop action to the
corresponding switch case to make it more clear and eliminating the
duplicated initialization of 'must_insert_reserved' to false.

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

diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index bf8c2ac..6a13cf0 100644 (file)
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -702,29 +702,33 @@ static void init_delayed_ref_head(struct btrfs_delayed_ref_head *head_ref,
        /* If reserved is provided, it must be a data extent. */
        BUG_ON(!is_data && reserved);
 
-       /*
-        * The head node stores the sum of all the mods, so dropping a ref
-        * should drop the sum in the head node by one.
-        */
-       if (action == BTRFS_UPDATE_DELAYED_HEAD)
+       switch (action) {
+       case BTRFS_UPDATE_DELAYED_HEAD:
                count_mod = 0;
-       else if (action == BTRFS_DROP_DELAYED_REF)
+               break;
+       case BTRFS_DROP_DELAYED_REF:
+               /*
+                * The head node stores the sum of all the mods, so dropping a ref
+                * should drop the sum in the head node by one.
+                */
                count_mod = -1;
-
-       /*
-        * BTRFS_ADD_DELAYED_EXTENT means that we need to update the reserved
-        * accounting when the extent is finally added, or if a later
-        * modification deletes the delayed ref without ever inserting the
-        * extent into the extent allocation tree.  ref->must_insert_reserved
-        * is the flag used to record that accounting mods are required.
-        *
-        * Once we record must_insert_reserved, switch the action to
-        * BTRFS_ADD_DELAYED_REF because other special casing is not required.
-        */
-       if (action == BTRFS_ADD_DELAYED_EXTENT)
+               break;
+       case BTRFS_ADD_DELAYED_EXTENT:
+               /*
+                * BTRFS_ADD_DELAYED_EXTENT means that we need to update the
+                * reserved accounting when the extent is finally added, or if a
+                * later modification deletes the delayed ref without ever
+                * inserting the extent into the extent allocation tree.
+                * ref->must_insert_reserved is the flag used to record that
+                * accounting mods are required.
+                *
+                * Once we record must_insert_reserved, switch the action to
+                * BTRFS_ADD_DELAYED_REF because other special casing is not
+                * required.
+                */
                must_insert_reserved = true;
-       else
-               must_insert_reserved = false;
+               break;
+       }
 
        refcount_set(&head_ref->refs, 1);
        head_ref->bytenr = bytenr;