Commit 970ea374 authored by David Sterba's avatar David Sterba
Browse files

btrfs: pass a valid extent map cache pointer to __get_extent_map() 



We can pass a valid em cache pointer down to __get_extent_map() and
drop the validity check. This avoids the special case, the call stacks
are simple:

btrfs_read_folio
  btrfs_do_readpage
    __get_extent_map

extent_readahead
  contiguous_readpages
    btrfs_do_readpage
      __get_extent_map

Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Reviewed-by: default avatarQu Wenruo <wqu@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 5a8a57f9

fs/btrfs/extent_io.c

+10 −3
Original line number Diff line number Diff line
@@ -970,7 +970,9 @@ static struct extent_map *__get_extent_map(struct inode *inode, struct page *pag 
{

	struct extent_map *em;



	if (em_cached && *em_cached) {

	ASSERT(em_cached);



	if (*em_cached) {

		em = *em_cached;

		if (extent_map_in_tree(em) && start >= em->start &&

		    start < extent_map_end(em)) {
@@ -983,7 +985,7 @@ static struct extent_map *__get_extent_map(struct inode *inode, struct page *pag 
	}



	em = btrfs_get_extent(BTRFS_I(inode), page, start, len);

	if (em_cached && !IS_ERR(em)) {

	if (!IS_ERR(em)) {

		BUG_ON(*em_cached);

		refcount_inc(&em->refs);

		*em_cached = em;
@@ -1154,11 +1156,14 @@ int btrfs_read_folio(struct file *file, struct folio *folio) 
	u64 start = page_offset(page);

	u64 end = start + PAGE_SIZE - 1;

	struct btrfs_bio_ctrl bio_ctrl = { .opf = REQ_OP_READ };

	struct extent_map *em_cached = NULL;

	int ret;



	btrfs_lock_and_flush_ordered_range(inode, start, end, NULL);



	ret = btrfs_do_readpage(page, NULL, &bio_ctrl, NULL);

	ret = btrfs_do_readpage(page, &em_cached, &bio_ctrl, NULL);

	free_extent_map(em_cached);



	/*

	 * If btrfs_do_readpage() failed we will want to submit the assembled

	 * bio to do the cleanup.
@@ -1176,6 +1181,8 @@ static inline void contiguous_readpages(struct page *pages[], int nr_pages, 
	struct btrfs_inode *inode = page_to_inode(pages[0]);

	int index;



	ASSERT(em_cached);



	btrfs_lock_and_flush_ordered_range(inode, start, end, NULL);



	for (index = 0; index < nr_pages; index++) {