[PATCH 04/12] fuse: support large folios for non-writeback writes

[Joanne Koong <joannelkoong@xxxxxxxxx>]

Add support for folios larger than one page size for non-writeback
writes.

Signed-off-by: Joanne Koong <joannelkoong@xxxxxxxxx>
---
 fs/fuse/file.c | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index a89fdc55a40b..6ee23ab9b7f2 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1146,19 +1146,15 @@ static ssize_t fuse_fill_write_pages(struct fuse_io_args *ia,
 	num = min(num, max_pages << PAGE_SHIFT);
 
 	ap->args.in_pages = true;
-	ap->descs[0].offset = offset;
 
 	while (num) {
 		size_t tmp;
 		struct folio *folio;
 		pgoff_t index = pos >> PAGE_SHIFT;
-		unsigned int bytes = min(PAGE_SIZE - offset, num);
-
- again:
-		err = -EFAULT;
-		if (fault_in_iov_iter_readable(ii, bytes))
-			break;
+		unsigned int bytes;
+		unsigned int folio_offset;
 
+	again:
 		folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
 					    mapping_gfp_mask(mapping));
 		if (IS_ERR(folio)) {
@@ -1166,10 +1162,20 @@ static ssize_t fuse_fill_write_pages(struct fuse_io_args *ia,
 			break;
 		}
 
+		folio_offset = ((index - folio->index) << PAGE_SHIFT) + offset;
+		bytes = min(folio_size(folio) - folio_offset, num);
+
+		err = -EFAULT;
+		if (fault_in_iov_iter_readable(ii, bytes)) {
+			folio_unlock(folio);
+			folio_put(folio);
+			break;
+		}
+
 		if (mapping_writably_mapped(mapping))
 			flush_dcache_folio(folio);
 
-		tmp = copy_folio_from_iter_atomic(folio, offset, bytes, ii);
+		tmp = copy_folio_from_iter_atomic(folio, folio_offset, bytes, ii);
 		flush_dcache_folio(folio);
 
 		if (!tmp) {
@@ -1180,6 +1186,7 @@ static ssize_t fuse_fill_write_pages(struct fuse_io_args *ia,
 
 		err = 0;
 		ap->folios[ap->num_folios] = folio;
+		ap->descs[ap->num_folios].offset = folio_offset;
 		ap->descs[ap->num_folios].length = tmp;
 		ap->num_folios++;
 
@@ -1187,11 +1194,11 @@ static ssize_t fuse_fill_write_pages(struct fuse_io_args *ia,
 		pos += tmp;
 		num -= tmp;
 		offset += tmp;
-		if (offset == PAGE_SIZE)
+		if (offset == folio_size(folio))
 			offset = 0;
 
-		/* If we copied full page, mark it uptodate */
-		if (tmp == PAGE_SIZE)
+		/* If we copied full folio, mark it uptodate */
+		if (tmp == folio_size(folio))
 			folio_mark_uptodate(folio);
 
 		if (folio_test_uptodate(folio)) {
-- 
2.43.5