libceph: distinguish page and bio requests

An osd request uses either pages or a bio list for its data.  Use a
union to record information about the two, and add a data type
tag to select between them.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 3a1a77b0ae9f..276fe96f12e3 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -243,6 +243,7 @@ static void finish_read(struct ceph_osd_request *req, struct ceph_msg *msg)
         dout("finish_read %p req %p rc %d bytes %d\n", inode, req, rc, bytes);
 
         /* unlock all pages, zeroing any data we didn't read */
+        BUG_ON(req->r_data.type != CEPH_OSD_DATA_TYPE_PAGES);
         for (i = 0; i < req->r_data.num_pages; i++, bytes -= PAGE_CACHE_SIZE) {
                 struct page *page = req->r_data.pages[i];
 
@@ -336,6 +337,7 @@ static int start_read(struct inode *inode, struct list_head *page_list, int max)
                 }
                 pages[i] = page;
         }
+        req->r_data.type = CEPH_OSD_DATA_TYPE_PAGES;
         req->r_data.pages = pages;
         req->r_data.num_pages = nr_pages;
         req->r_data.alignment = 0;
@@ -561,6 +563,7 @@ static void writepages_finish(struct ceph_osd_request *req,
         long writeback_stat;
         unsigned issued = ceph_caps_issued(ci);
 
+        BUG_ON(req->r_data.type != CEPH_OSD_DATA_TYPE_PAGES);
         if (rc >= 0) {
                 /*
                  * Assume we wrote the pages we originally sent.  The
@@ -830,6 +833,7 @@ get_more_pages:
                                         break;
                                 }
 
+                                req->r_data.type = CEPH_OSD_DATA_TYPE_PAGES;
                                 req->r_data.num_pages = calc_pages_for(0, len);
                                 req->r_data.alignment = 0;
                                 max_pages = req->r_data.num_pages;