btrfs: make the rule checking more readable for should_cow_block()

Browse source

It's quite hard and unreadable the way the rule checks are organized in
should_cow_block(). We have a single if statement that returns 0 (false)
and it checks several conditions, with one them being a negated compound
condition which is particularly hard to reason immediately.

Improve on this by using multiple if statements, each checking a single
condition and returning immediately. Also change the return type from an
integer to a boolean, since all we need is to return true or false.

At least on x86_64 with Debian's gcc 14.2.0-19, this also reduces the
object code size by 64 bytes.

Before this change:

   $ size fs/btrfs/btrfs.ko
      text	   data	    bss	    dec	    hex	filename
   1913327	 161567	  15592	2090486	 1fe5f6	fs/btrfs/btrfs.ko

After this change:

   $ size fs/btrfs/btrfs.ko
      text	   data	    bss	    dec	    hex	filename
   1913263	 161567	  15592	2090422	 1fe5b6	fs/btrfs/btrfs.ko

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

...

This commit is contained in:

Filipe Manana 2025-09-19 09:16:20 +01:00 • committed by David Sterba

parent b7ff7b0d76

commit f07575bab6

1 changed files with 23 additions and 14 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

37

fs/btrfs/ctree.c

View file