Commit 13df3775 authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: cleanup metadata page pointer usage 



Although we have migrated extent_buffer::pages[] to folios[], we're
still mostly using the folio_page() help to grab the page.

This patch would do the following cleanups for metadata:

- Introduce num_extent_folios() helper
  This is to replace most num_extent_pages() callers.

- Use num_extent_folios() to iterate future large folios
  This allows us to use things like
  bio_add_folio()/bio_add_folio_nofail(), and only set the needed flags
  for the folio (aka the leading/tailing page), which reduces the loop
  iteration to 1 for large folios.

- Change metadata related functions to use folio pointers
  Including their function name, involving:
  * attach_extent_buffer_page()
  * detach_extent_buffer_page()
  * page_range_has_eb()
  * btrfs_release_extent_buffer_pages()
  * btree_clear_page_dirty()
  * btrfs_page_inc_eb_refs()
  * btrfs_page_dec_eb_refs()

- Change btrfs_is_subpage() to accept an address_space pointer
  This is to allow both page->mapping and folio->mapping to be utilized.
  As data is still using the old per-page code, and may keep so for a
  while.

- Special corner case place holder for future order mismatches between
  extent buffer and inode filemap
  For now it's  just a block of comments and a dead ASSERT(), no real
  handling yet.

The subpage code would still go page, just because subpage and large
folio are conflicting conditions, thus we don't need to bother subpage
with higher order folios at all. Just folio_page(folio, 0) would be
enough.

Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
[ minor styling tweaks ]
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 082d5bb9

fs/btrfs/disk-io.c

+6 −0
Original line number Diff line number Diff line
@@ -97,6 +97,12 @@ static void csum_tree_block(struct extent_buffer *buf, u8 *result) 
	crypto_shash_update(shash, kaddr + BTRFS_CSUM_SIZE,

			    first_page_part - BTRFS_CSUM_SIZE);



	/*

	 * Multiple single-page folios case would reach here.

	 *

	 * nodesize <= PAGE_SIZE and large folio all handled by above

	 * crypto_shash_update() already.

	 */

	for (i = 1; i < num_pages && INLINE_EXTENT_BUFFER_PAGES > 1; i++) {

		kaddr = folio_address(buf->folios[i]);

		crypto_shash_update(shash, kaddr, PAGE_SIZE);

fs/btrfs/extent_io.c

+172 −147

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fs/btrfs/extent_io.h

+14 −0
Original line number Diff line number Diff line
@@ -243,6 +243,20 @@ static inline int num_extent_pages(const struct extent_buffer *eb) 
	return (eb->len >> PAGE_SHIFT) ?: 1;

}



/*

 * This can only be determined at runtime by checking eb::folios[0].

 *

 * As we can have either one large folio covering the whole eb

 * (either nodesize <= PAGE_SIZE, or high order folio), or multiple

 * single-paged folios.

 */

static inline int num_extent_folios(const struct extent_buffer *eb)

{

	if (folio_order(eb->folios[0]))

		return 1;

	return num_extent_pages(eb);

}



static inline int extent_buffer_uptodate(const struct extent_buffer *eb)

{

	return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);

fs/btrfs/inode.c

+1 −1
Original line number Diff line number Diff line
@@ -7867,7 +7867,7 @@ static void wait_subpage_spinlock(struct page *page) 
	struct folio *folio = page_folio(page);

	struct btrfs_subpage *subpage;



	if (!btrfs_is_subpage(fs_info, page))

	if (!btrfs_is_subpage(fs_info, page->mapping))

		return;



	ASSERT(folio_test_private(folio) && folio_get_private(folio));

fs/btrfs/subpage.c

+28 −27

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