fuse: use req->page_descs[] for argpages cases

Previously, anyone who set flag 'argpages' only filled req->pages[] and set
per-request page_offset. This patch re-works all cases where argpages=1 to
fill req->page_descs[] properly.

Having req->page_descs[] filled properly allows to re-work fuse_copy_pages()
to copy page fragments described by req->page_descs[]. This will be useful
for next patches optimizing direct_IO.

Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

1 files changed, 3 insertions, 4 deletions

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index db4af8f3886a..cbae09e5a491 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -903,11 +903,11 @@ static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
 {
         unsigned i;
         struct fuse_req *req = cs->req;
-        unsigned offset = req->page_descs[0].offset;
-        unsigned count = min(nbytes, (unsigned) PAGE_SIZE - offset);
 
         for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
                 int err;
+                unsigned offset = req->page_descs[i].offset;
+                unsigned count = min(nbytes, req->page_descs[i].length);
 
                 err = fuse_copy_page(cs, &req->pages[i], offset, count,
                                      zeroing);
@@ -915,8 +915,6 @@ static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
                         return err;
 
                 nbytes -= count;
-                count = min(nbytes, (unsigned) PAGE_SIZE);
-                offset = 0;
         }
         return 0;
 }
@@ -1626,6 +1624,7 @@ static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
 
                 this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
                 req->pages[req->num_pages] = page;
+                req->page_descs[req->num_pages].length = this_num;
                 req->num_pages++;
 
                 offset = 0;