Commit 87d6aaf7 authored by Filipe Manana's avatar Filipe Manana Committed by David Sterba
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btrfs: avoid assigning twice to block_start at btrfs_do_readpage() 



At btrfs_do_readpage() if we get an extent map for a prealloc extent we
end up assigning twice to the 'block_start' variable, first the value
returned by extent_map_block_start() and then EXTENT_MAP_HOLE. This is
pointless so make it more clear by using an if-else statement and doing
only one assignment. Also, while at it, move the declaration of
'block_start' into the while loop's scope, since it's not used outside of
it and the related 'disk_bytenr' is also declared in this scope.

Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 968f19c5

fs/btrfs/extent_io.c

+4 −2
Original line number Diff line number Diff line
@@ -939,7 +939,6 @@ static int btrfs_do_readpage(struct folio *folio, struct extent_map **em_cached, 
	u64 cur = start;

	u64 extent_offset;

	u64 last_byte = i_size_read(inode);

	u64 block_start;

	struct extent_map *em;

	int ret = 0;

	size_t pg_offset = 0;
@@ -966,6 +965,7 @@ static int btrfs_do_readpage(struct folio *folio, struct extent_map **em_cached, 
		enum btrfs_compression_type compress_type = BTRFS_COMPRESS_NONE;

		bool force_bio_submit = false;

		u64 disk_bytenr;

		u64 block_start;



		ASSERT(IS_ALIGNED(cur, fs_info->sectorsize));

		if (cur >= last_byte) {
@@ -991,9 +991,11 @@ static int btrfs_do_readpage(struct folio *folio, struct extent_map **em_cached, 
			disk_bytenr = em->disk_bytenr;

		else

			disk_bytenr = extent_map_block_start(em) + extent_offset;

		block_start = extent_map_block_start(em);



		if (em->flags & EXTENT_FLAG_PREALLOC)

			block_start = EXTENT_MAP_HOLE;

		else

			block_start = extent_map_block_start(em);



		/*

		 * If we have a file range that points to a compressed extent