Commit ab6eac7c authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: remove btrfs_folio_end_all_writers() 



The function btrfs_folio_end_all_writers() is only utilized in
extent_writepage() as a way to unlock all subpage range (for both
successful submission and error handling).

Meanwhile we have a similar function, btrfs_folio_end_writer_lock().

The difference is, btrfs_folio_end_writer_lock() expects a range that is
a subset of the already locked range.

This limit on btrfs_folio_end_writer_lock() is a little overkilled,
preventing it from being utilized for error paths.

So here we enhance btrfs_folio_end_writer_lock() to accept a superset of
the locked range, and only end the locked subset.
This means we can replace btrfs_folio_end_all_writers() with
btrfs_folio_end_writer_lock() instead.

Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent ca283ea9

fs/btrfs/extent_io.c

+2 −1
Original line number Diff line number Diff line
@@ -1466,7 +1466,8 @@ static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl 
		mapping_set_error(folio->mapping, ret);

	}



	btrfs_folio_end_all_writers(inode_to_fs_info(inode), folio);

	btrfs_folio_end_writer_lock(inode_to_fs_info(inode), folio,

				    page_start, PAGE_SIZE);

	ASSERT(ret <= 0);

	return ret;

}

fs/btrfs/subpage.c

+8 −49
Original line number Diff line number Diff line
@@ -322,6 +322,8 @@ static bool btrfs_subpage_end_and_test_writer(const struct btrfs_fs_info *fs_inf 
	const int start_bit = subpage_calc_start_bit(fs_info, folio, locked, start, len);

	const int nbits = (len >> fs_info->sectorsize_bits);

	unsigned long flags;

	unsigned int cleared = 0;

	int bit = start_bit;

	bool last;



	btrfs_subpage_assert(fs_info, folio, start, len);
@@ -339,11 +341,12 @@ static bool btrfs_subpage_end_and_test_writer(const struct btrfs_fs_info *fs_inf 
		return true;

	}



	ASSERT(atomic_read(&subpage->writers) >= nbits);

	/* The target range should have been locked. */

	ASSERT(bitmap_test_range_all_set(subpage->bitmaps, start_bit, nbits));

	bitmap_clear(subpage->bitmaps, start_bit, nbits);

	last = atomic_sub_and_test(nbits, &subpage->writers);

	for_each_set_bit_from(bit, subpage->bitmaps, start_bit + nbits) {

		clear_bit(bit, subpage->bitmaps);

		cleared++;

	}

	ASSERT(atomic_read(&subpage->writers) >= cleared);

	last = atomic_sub_and_test(cleared, &subpage->writers);

	spin_unlock_irqrestore(&subpage->lock, flags);

	return last;

}
@@ -825,50 +828,6 @@ bool btrfs_subpage_find_writer_locked(const struct btrfs_fs_info *fs_info, 
	return found;

}



/*

 * Unlike btrfs_folio_end_writer_lock() which unlocks a specified subpage range,

 * this ends all writer locked ranges of a page.

 *

 * This is for the locked page of extent_writepage(), as the locked page

 * can contain several locked subpage ranges.

 */

void btrfs_folio_end_all_writers(const struct btrfs_fs_info *fs_info, struct folio *folio)

{

	struct btrfs_subpage *subpage = folio_get_private(folio);

	u64 folio_start = folio_pos(folio);

	u64 cur = folio_start;



	ASSERT(folio_test_locked(folio));

	if (!btrfs_is_subpage(fs_info, folio->mapping)) {

		folio_unlock(folio);

		return;

	}



	/* The page has no new delalloc range locked on it. Just plain unlock. */

	if (atomic_read(&subpage->writers) == 0) {

		folio_unlock(folio);

		return;

	}

	while (cur < folio_start + PAGE_SIZE) {

		u64 found_start;

		u32 found_len;

		bool found;

		bool last;



		found = btrfs_subpage_find_writer_locked(fs_info, folio, cur,

							 &found_start, &found_len);

		if (!found)

			break;

		last = btrfs_subpage_end_and_test_writer(fs_info, folio,

							 found_start, found_len);

		if (last) {

			folio_unlock(folio);

			break;

		}

		cur = found_start + found_len;

	}

}



#define GET_SUBPAGE_BITMAP(subpage, fs_info, name, dst)			\

{									\

	const int sectors_per_page = fs_info->sectors_per_page;		\

fs/btrfs/subpage.h

+0 −1
Original line number Diff line number Diff line
@@ -109,7 +109,6 @@ void btrfs_folio_set_writer_lock(const struct btrfs_fs_info *fs_info, 
bool btrfs_subpage_find_writer_locked(const struct btrfs_fs_info *fs_info,

				      struct folio *folio, u64 search_start,

				      u64 *found_start_ret, u32 *found_len_ret);

void btrfs_folio_end_all_writers(const struct btrfs_fs_info *fs_info, struct folio *folio);



/*

 * Template for subpage related operations.