fuse: support large folios for retrieves

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>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Bernd Schubert <bschubert@ddn.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index f8fd24df173c873bdb2d883955db77ae78123f19..b7d0a81c5df15c38f7960dd60ba7a9c03c4b905a 100644 (file)
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1849,7 +1849,7 @@ 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);
@@ -1867,6 +1867,7 @@ 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]));
 
@@ -1887,25 +1888,29 @@ 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;