[PATCH v2 02/12] fuse: support large folios for retrieves

Joanne Koong
2024-11-25T22:05:59Z

Add support for folios larger than one page size for retrieves.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
---
fs/fuse/dev.c | 25 +++++++++++++++----------
1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 4a09c41910d7..8d6418972fe5 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1716,7 +1716,7 @@ static int fuse_retrieve(struct fuse_mount *fm, struct inode *inode,
unsigned int num;
unsigned int offset;
size_t total_len = 0;
- unsigned int num_pages, cur_pages = 0;
+ unsigned int num_pages;
struct fuse_conn *fc = fm->fc;
struct fuse_retrieve_args *ra;
size_t args_size = sizeof(*ra);
@@ -1734,6 +1734,7 @@ static int fuse_retrieve(struct fuse_mount *fm, struct inode *inode,

num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
num_pages = min(num_pages, fc->max_pages);
+ num = min(num, num_pages << PAGE_SHIFT);

args_size += num_pages * (sizeof(ap->folios[0]) + sizeof(ap->descs[0]));

@@ -1754,25 +1755,29 @@ static int fuse_retrieve(struct fuse_mount *fm, struct inode *inode,

index = outarg->offset >> PAGE_SHIFT;

- while (num && cur_pages < num_pages) {
+ while (num) {
struct folio *folio;
- unsigned int this_num;
+ unsigned int folio_offset;
+ unsigned int nr_bytes;
+ unsigned int nr_pages;

folio = filemap_get_folio(mapping, index);
if (IS_ERR(folio))
break;

- this_num = min_t(unsigned, num, PAGE_SIZE - offset);
+ folio_offset = ((index - folio->index) << PAGE_SHIFT) + offset;
+ nr_bytes = min(folio_size(folio) - folio_offset, num);
+ nr_pages = (offset + nr_bytes + PAGE_SIZE - 1) >> PAGE_SHIFT;
+
ap->folios[ap->num_folios] = folio;
- ap->descs[ap->num_folios].offset = offset;
- ap->descs[ap->num_folios].length = this_num;
+ ap->descs[ap->num_folios].offset = folio_offset;
+ ap->descs[ap->num_folios].length = nr_bytes;
ap->num_folios++;
- cur_pages++;

offset = 0;
- num -= this_num;
- total_len += this_num;
- index++;
+ num -= nr_bytes;
+ total_len += nr_bytes;
+ index += nr_pages;
}
ra->inarg.offset = outarg->offset;
ra->inarg.size = total_len;
--
2.43.5