On Sun, Aug 11, 2024 at 1:59 PM Sasha Levin <sashal@xxxxxxxxxx> wrote: > > This is a note to let you know that I've just added the patch titled > > btrfs: reduce nesting for extent processing at btrfs_lookup_extent_info() > > to the 6.10-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > The filename of the patch is: > btrfs-reduce-nesting-for-extent-processing-at-btrfs_.patch > and it can be found in the queue-6.10 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable@xxxxxxxxxxxxxxx> know about it. Why is this being added to stable releases? It's just a cleanup, it doesn't fix any bug or compiler warning, etc. > > > > commit 5a0873e18421183cf695cc5f2c851aac4e1d832c > Author: Filipe Manana <fdmanana@xxxxxxxx> > Date: Tue Jun 18 11:52:19 2024 +0100 > > btrfs: reduce nesting for extent processing at btrfs_lookup_extent_info() > > [ Upstream commit 5c83b3beaee06aa88d4015408ac2d8bb35380b06 ] > > Instead of using an if-else statement when processing the extent item at > btrfs_lookup_extent_info(), use a single if statement for the error case > since it does a goto at the end and leave the success (expected) case > following the if statement, reducing indentation and making the logic a > bit easier to follow. Also make the if statement's condition as unlikely > since it's not expected to ever happen, as it signals some corruption, > making it clear and hint the compiler to generate more efficient code. > > Reviewed-by: Qu Wenruo <wqu@xxxxxxxx> > Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx> > Signed-off-by: David Sterba <dsterba@xxxxxxxx> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c > index 153297cb97a4a..844b677d054ec 100644 > --- a/fs/btrfs/extent-tree.c > +++ b/fs/btrfs/extent-tree.c > @@ -104,10 +104,7 @@ int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans, > struct btrfs_delayed_ref_head *head; > struct btrfs_delayed_ref_root *delayed_refs; > struct btrfs_path *path; > - struct btrfs_extent_item *ei; > - struct extent_buffer *leaf; > struct btrfs_key key; > - u32 item_size; > u64 num_refs; > u64 extent_flags; > u64 owner = 0; > @@ -157,16 +154,11 @@ int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans, > } > > if (ret == 0) { > - leaf = path->nodes[0]; > - item_size = btrfs_item_size(leaf, path->slots[0]); > - if (item_size >= sizeof(*ei)) { > - ei = btrfs_item_ptr(leaf, path->slots[0], > - struct btrfs_extent_item); > - num_refs = btrfs_extent_refs(leaf, ei); > - extent_flags = btrfs_extent_flags(leaf, ei); > - owner = btrfs_get_extent_owner_root(fs_info, leaf, > - path->slots[0]); > - } else { > + struct extent_buffer *leaf = path->nodes[0]; > + struct btrfs_extent_item *ei; > + const u32 item_size = btrfs_item_size(leaf, path->slots[0]); > + > + if (unlikely(item_size < sizeof(*ei))) { > ret = -EUCLEAN; > btrfs_err(fs_info, > "unexpected extent item size, has %u expect >= %zu", > @@ -179,6 +171,10 @@ int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans, > goto out_free; > } > > + ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item); > + num_refs = btrfs_extent_refs(leaf, ei); > + extent_flags = btrfs_extent_flags(leaf, ei); > + owner = btrfs_get_extent_owner_root(fs_info, leaf, path->slots[0]); > BUG_ON(num_refs == 0); > } else { > num_refs = 0;
