Commit 98321b51 authored by Andreas Gruenbacher's avatar Andreas Gruenbacher Committed by Darrick J. Wong
Browse files

iomap: Add iomap_get_folio helper 



Add an iomap_get_folio() helper that gets a folio reference based on
an iomap iterator and an offset into the address space.  Use it in
iomap_write_begin().

Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
parent 40405ddd

fs/iomap/buffered-io.c

+30 −9
Original line number Diff line number Diff line
@@ -457,6 +457,33 @@ bool iomap_is_partially_uptodate(struct folio *folio, size_t from, size_t count) 
}

EXPORT_SYMBOL_GPL(iomap_is_partially_uptodate);



/**

 * iomap_get_folio - get a folio reference for writing

 * @iter: iteration structure

 * @pos: start offset of write

 *

 * Returns a locked reference to the folio at @pos, or an error pointer if the

 * folio could not be obtained.

 */

struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos)

{

	unsigned fgp = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE | FGP_NOFS;

	struct folio *folio;



	if (iter->flags & IOMAP_NOWAIT)

		fgp |= FGP_NOWAIT;



	folio = __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT,

			fgp, mapping_gfp_mask(iter->inode->i_mapping));

	if (folio)

		return folio;



	if (iter->flags & IOMAP_NOWAIT)

		return ERR_PTR(-EAGAIN);

	return ERR_PTR(-ENOMEM);

}

EXPORT_SYMBOL_GPL(iomap_get_folio);



bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags)

{

	trace_iomap_release_folio(folio->mapping->host, folio_pos(folio),
@@ -603,12 +630,8 @@ static int iomap_write_begin(struct iomap_iter *iter, loff_t pos, 
	const struct iomap_page_ops *page_ops = iter->iomap.page_ops;

	const struct iomap *srcmap = iomap_iter_srcmap(iter);

	struct folio *folio;

	unsigned fgp = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE | FGP_NOFS;

	int status = 0;



	if (iter->flags & IOMAP_NOWAIT)

		fgp |= FGP_NOWAIT;



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

	if (srcmap != &iter->iomap)

		BUG_ON(pos + len > srcmap->offset + srcmap->length);
@@ -625,12 +648,10 @@ static int iomap_write_begin(struct iomap_iter *iter, loff_t pos, 
			return status;

	}



	folio = __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT,

			fgp, mapping_gfp_mask(iter->inode->i_mapping));

	if (!folio) {

		status = (iter->flags & IOMAP_NOWAIT) ? -EAGAIN : -ENOMEM;

	folio = iomap_get_folio(iter, pos);

	if (IS_ERR(folio)) {

		__iomap_put_folio(iter, pos, 0, NULL);

		return status;

		return PTR_ERR(folio);

	}



	/*

include/linux/iomap.h

+1 −0
Original line number Diff line number Diff line
@@ -261,6 +261,7 @@ int iomap_file_buffered_write_punch_delalloc(struct inode *inode, 
int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops);

void iomap_readahead(struct readahead_control *, const struct iomap_ops *ops);

bool iomap_is_partially_uptodate(struct folio *, size_t from, size_t count);

struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos);

bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags);

void iomap_invalidate_folio(struct folio *folio, size_t offset, size_t len);

int iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len,