Unverified Commit 66c0d855 authored by Brian Foster's avatar Brian Foster Committed by Christian Brauner
Browse files

iomap: rework iomap_write_begin() to return folio offset and length 



iomap_write_begin() returns a folio based on current pos and
remaining length in the iter, and each caller then trims the
pos/length to the given folio. Clean this up a bit and let
iomap_write_begin() return the trimmed range along with the folio.

Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
Link: https://lore.kernel.org/20250506134118.911396-7-bfoster@redhat.com


Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent c0f8658a

fs/iomap/buffered-io.c

+19 −14
Original line number Diff line number Diff line
@@ -679,11 +679,12 @@ static int iomap_read_folio_sync(loff_t block_start, struct folio *folio, 
	return submit_bio_wait(&bio);

}



static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos,

		size_t len, struct folio *folio)

static int __iomap_write_begin(const struct iomap_iter *iter, size_t len,

		struct folio *folio)

{

	const struct iomap *srcmap = iomap_iter_srcmap(iter);

	struct iomap_folio_state *ifs;

	loff_t pos = iter->pos;

	loff_t block_size = i_blocksize(iter->inode);

	loff_t block_start = round_down(pos, block_size);

	loff_t block_end = round_up(pos + len, block_size);
@@ -794,15 +795,22 @@ static int iomap_write_begin_inline(const struct iomap_iter *iter, 
	return iomap_read_inline_data(iter, folio);

}



static int iomap_write_begin(struct iomap_iter *iter, size_t len,

		struct folio **foliop)

/*

 * Grab and prepare a folio for write based on iter state. Returns the folio,

 * offset, and length. Callers can optionally pass a max length *plen,

 * otherwise init to zero.

 */

static int iomap_write_begin(struct iomap_iter *iter, struct folio **foliop,

		size_t *poffset, u64 *plen)

{

	const struct iomap_folio_ops *folio_ops = iter->iomap.folio_ops;

	const struct iomap *srcmap = iomap_iter_srcmap(iter);

	loff_t pos = iter->pos;

	u64 len = min_t(u64, SIZE_MAX, iomap_length(iter));

	struct folio *folio;

	int status = 0;



	len = min_not_zero(len, *plen);

	BUG_ON(pos + len > iter->iomap.offset + iter->iomap.length);

	if (srcmap != &iter->iomap)

		BUG_ON(pos + len > srcmap->offset + srcmap->length);
@@ -834,20 +842,20 @@ static int iomap_write_begin(struct iomap_iter *iter, size_t len, 
		}

	}



	if (pos + len > folio_pos(folio) + folio_size(folio))

		len = folio_pos(folio) + folio_size(folio) - pos;

	pos = iomap_trim_folio_range(iter, folio, poffset, &len);



	if (srcmap->type == IOMAP_INLINE)

		status = iomap_write_begin_inline(iter, folio);

	else if (srcmap->flags & IOMAP_F_BUFFER_HEAD)

		status = __block_write_begin_int(folio, pos, len, NULL, srcmap);

	else

		status = __iomap_write_begin(iter, pos, len, folio);

		status = __iomap_write_begin(iter, len, folio);



	if (unlikely(status))

		goto out_unlock;



	*foliop = folio;

	*plen = len;

	return 0;



out_unlock:
@@ -968,7 +976,7 @@ static int iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i) 
			break;

		}



		status = iomap_write_begin(iter, bytes, &folio);

		status = iomap_write_begin(iter, &folio, &offset, &bytes);

		if (unlikely(status)) {

			iomap_write_failed(iter->inode, iter->pos, bytes);

			break;
@@ -976,7 +984,7 @@ static int iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i) 
		if (iter->iomap.flags & IOMAP_F_STALE)

			break;



		pos = iomap_trim_folio_range(iter, folio, &offset, &bytes);

		pos = iter->pos;



		if (mapping_writably_mapped(mapping))

			flush_dcache_folio(folio);
@@ -1296,14 +1304,12 @@ static int iomap_unshare_iter(struct iomap_iter *iter) 
		bool ret;



		bytes = min_t(u64, SIZE_MAX, bytes);

		status = iomap_write_begin(iter, bytes, &folio);

		status = iomap_write_begin(iter, &folio, &offset, &bytes);

		if (unlikely(status))

			return status;

		if (iomap->flags & IOMAP_F_STALE)

			break;



		iomap_trim_folio_range(iter, folio, &offset, &bytes);



		ret = iomap_write_end(iter, bytes, bytes, folio);

		__iomap_put_folio(iter, bytes, folio);

		if (WARN_ON_ONCE(!ret))
@@ -1368,7 +1374,7 @@ static int iomap_zero_iter(struct iomap_iter *iter, bool *did_zero) 
		bool ret;



		bytes = min_t(u64, SIZE_MAX, bytes);

		status = iomap_write_begin(iter, bytes, &folio);

		status = iomap_write_begin(iter, &folio, &offset, &bytes);

		if (status)

			return status;

		if (iter->iomap.flags & IOMAP_F_STALE)
@@ -1377,7 +1383,6 @@ static int iomap_zero_iter(struct iomap_iter *iter, bool *did_zero) 
		/* warn about zeroing folios beyond eof that won't write back */

		WARN_ON_ONCE(folio_pos(folio) > iter->inode->i_size);



		iomap_trim_folio_range(iter, folio, &offset, &bytes);

		folio_zero_range(folio, offset, bytes);

		folio_mark_accessed(folio);