btrfs: pass a space_info argument to btrfs_reserve_metadata_bytes()

We are passing a block reserve argument to btrfs_reserve_metadata_bytes()
which is not really used, all we need is to pass the space_info associated
to the block reserve, we don't change the block reserve at all.

Not only it's pointless to pass the block reserve, it's also confusing as
one might think that the reserved bytes will end up being added to the
passed block reserve, when that's not the case. The pattern for reserving
space and adding it to a block reserve is to first reserve space with
btrfs_reserve_metadata_bytes() and if that succeeds, then add the space to
a block reserve by calling btrfs_block_rsv_add_bytes().

Also the reverse of btrfs_reserve_metadata_bytes(), which is
btrfs_space_info_free_bytes_may_use(), takes a space_info argument and
not a block reserve, so one more reason to pass a space_info and not a
block reserve to btrfs_reserve_metadata_bytes().

So change btrfs_reserve_metadata_bytes() and its callers to pass a
space_info argument instead of a block reserve argument.

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

1 files changed, 5 insertions, 7 deletions

diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index 58de9a14e525..d2296bc66fbe 100644
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -1743,7 +1743,7 @@ static int __reserve_bytes(struct btrfs_fs_info *fs_info,
  * Try to reserve metadata bytes from the block_rsv's space.
  *
  * @fs_info:    the filesystem
- * @block_rsv:  block_rsv we're allocating for
+ * @space_info: the space_info we're allocating for
  * @orig_bytes: number of bytes we want
  * @flush:      whether or not we can flush to make our reservation
  *
@@ -1755,21 +1755,19 @@ static int __reserve_bytes(struct btrfs_fs_info *fs_info,
  * space already.
  */
 int btrfs_reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
-				 struct btrfs_block_rsv *block_rsv,
+				 struct btrfs_space_info *space_info,
 				 u64 orig_bytes,
 				 enum btrfs_reserve_flush_enum flush)
 {
 	int ret;
 
-	ret = __reserve_bytes(fs_info, block_rsv->space_info, orig_bytes, flush);
+	ret = __reserve_bytes(fs_info, space_info, orig_bytes, flush);
 	if (ret == -ENOSPC) {
 		trace_btrfs_space_reservation(fs_info, "space_info:enospc",
-					      block_rsv->space_info->flags,
-					      orig_bytes, 1);
+					      space_info->flags, orig_bytes, 1);
 
 		if (btrfs_test_opt(fs_info, ENOSPC_DEBUG))
-			btrfs_dump_space_info(fs_info, block_rsv->space_info,
-					      orig_bytes, 0);
+			btrfs_dump_space_info(fs_info, space_info, orig_bytes, 0);
 	}
 	return ret;
 }