Commit cfd7a17d authored by Filipe Manana's avatar Filipe Manana Committed by David Sterba
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btrfs: remove no longer used btrfs_next_extent_map() 



There are no more users of btrfs_next_extent_map(), the previous patch
in the series ("btrfs: search for delalloc more efficiently during
lseek/fiemap") removed the last usage of the function, so delete it.

This change is part of a patchset that has the goal to make performance
better for applications that use lseek's SEEK_HOLE and SEEK_DATA modes to
iterate over the extents of a file. Two examples are the cp program from
coreutils 9.0+ and the tar program (when using its --sparse / -S option).
A sample test and results are listed in the changelog of the last patch
in the series:

  1/9 btrfs: remove leftover setting of EXTENT_UPTODATE state in an inode's io_tree
  2/9 btrfs: add an early exit when searching for delalloc range for lseek/fiemap
  3/9 btrfs: skip unnecessary delalloc searches during lseek/fiemap
  4/9 btrfs: search for delalloc more efficiently during lseek/fiemap
  5/9 btrfs: remove no longer used btrfs_next_extent_map()
  6/9 btrfs: allow passing a cached state record to count_range_bits()
  7/9 btrfs: update stale comment for count_range_bits()
  8/9 btrfs: use cached state when looking for delalloc ranges with fiemap
  9/9 btrfs: use cached state when looking for delalloc ranges with lseek

Reported-by: default avatarWang Yugui <wangyugui@e16-tech.com>
Link: https://lore.kernel.org/linux-btrfs/20221106073028.71F9.409509F4@e16-tech.com/
Link: https://lore.kernel.org/linux-btrfs/CAL3q7H5NSVicm7nYBJ7x8fFkDpno8z3PYt5aPU43Bajc1H0h1Q@mail.gmail.com/


Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 8ddc8274

fs/btrfs/extent_map.c

+0 −29
Original line number Diff line number Diff line
@@ -529,35 +529,6 @@ static struct extent_map *next_extent_map(const struct extent_map *em) 
	return container_of(next, struct extent_map, rb_node);

}



/*

 * Get the extent map that immediately follows another one.

 *

 * @tree:       The extent map tree that the extent map belong to.

 *              Holding read or write access on the tree's lock is required.

 * @em:         An extent map from the given tree. The caller must ensure that

 *              between getting @em and between calling this function, the

 *              extent map @em is not removed from the tree - for example, by

 *              holding the tree's lock for the duration of those 2 operations.

 *

 * Returns the extent map that immediately follows @em, or NULL if @em is the

 * last extent map in the tree.

 */

struct extent_map *btrfs_next_extent_map(const struct extent_map_tree *tree,

					 const struct extent_map *em)

{

	struct extent_map *next;



	/* The lock must be acquired either in read mode or write mode. */

	lockdep_assert_held(&tree->lock);

	ASSERT(extent_map_in_tree(em));



	next = next_extent_map(em);

	if (next)

		refcount_inc(&next->refs);



	return next;

}



static struct extent_map *prev_extent_map(struct extent_map *em)

{

	struct rb_node *prev;

fs/btrfs/extent_map.h

+0 −2
Original line number Diff line number Diff line
@@ -87,8 +87,6 @@ static inline u64 extent_map_block_end(struct extent_map *em) 
void extent_map_tree_init(struct extent_map_tree *tree);

struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,

					 u64 start, u64 len);

struct extent_map *btrfs_next_extent_map(const struct extent_map_tree *tree,

					 const struct extent_map *em);

int add_extent_mapping(struct extent_map_tree *tree,

		       struct extent_map *em, int modified);

void remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em);