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>

5 files changed, 55 insertions, 21 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 0e814dfda48e..f189bc2909b0 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -1425,12 +1425,16 @@ static struct ceph_osd_request *rbd_osd_req_create(
                 break;          /* Nothing to do */
         case OBJ_REQUEST_BIO:
                 rbd_assert(obj_request->bio_list != NULL);
+                osd_req->r_data.type = CEPH_OSD_DATA_TYPE_BIO;
                 osd_req->r_data.bio = obj_request->bio_list;
                 break;
         case OBJ_REQUEST_PAGES:
+                osd_req->r_data.type = CEPH_OSD_DATA_TYPE_PAGES;
                 osd_req->r_data.pages = obj_request->pages;
                 osd_req->r_data.num_pages = obj_request->page_count;
                 osd_req->r_data.alignment = offset & ~PAGE_MASK;
+                osd_req->r_data.pages_from_pool = false;
+                osd_req->r_data.own_pages = false;
                 break;
         }
 
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;
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index d35fc05af06f..3643a386ab23 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -571,6 +571,7 @@ more:
                         req->r_data.own_pages = 1;
                 }
         }
+        req->r_data.type = CEPH_OSD_DATA_TYPE_PAGES;
         req->r_data.pages = pages;
         req->r_data.num_pages = num_pages;
         req->r_data.alignment = page_align;
diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_client.h
index 600b8278d11e..56604b33dc3c 100644
--- a/include/linux/ceph/osd_client.h
+++ b/include/linux/ceph/osd_client.h
@@ -50,8 +50,17 @@ struct ceph_osd {
 
 #define CEPH_OSD_MAX_OP 10
 
+enum ceph_osd_data_type {
+        CEPH_OSD_DATA_TYPE_NONE,
+        CEPH_OSD_DATA_TYPE_PAGES,
+#ifdef CONFIG_BLOCK
+        CEPH_OSD_DATA_TYPE_BIO,
+#endif /* CONFIG_BLOCK */
+};
+
 struct ceph_osd_data {
-        struct {
+        enum ceph_osd_data_type type;
+        union {
                 struct {
                         struct page     **pages;
                         u32             num_pages;
diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 1f8c7a7c203b..591e1b0cccbe 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -122,7 +122,8 @@ void ceph_osdc_release_request(struct kref *kref)
         }
         if (req->r_reply)
                 ceph_msg_put(req->r_reply);
-        if (req->r_data.own_pages)
+        if (req->r_data.type == CEPH_OSD_DATA_TYPE_PAGES &&
+                        req->r_data.own_pages)
                 ceph_release_page_vector(req->r_data.pages,
                                          req->r_data.num_pages);
         ceph_put_snap_context(req->r_snapc);
@@ -188,6 +189,7 @@ struct ceph_osd_request *ceph_osdc_alloc_request(struct ceph_osd_client *osdc,
         }
         req->r_reply = msg;
 
+        req->r_data.type = CEPH_OSD_DATA_TYPE_NONE;
         ceph_pagelist_init(&req->r_trail);
 
         /* create request message; allow space for oid */
@@ -1739,12 +1741,17 @@ int ceph_osdc_start_request(struct ceph_osd_client *osdc,
 {
         int rc = 0;
 
-        req->r_request->pages = req->r_data.pages;
-        req->r_request->page_count = req->r_data.num_pages;
-        req->r_request->page_alignment = req->r_data.alignment;
+        if (req->r_data.type == CEPH_OSD_DATA_TYPE_PAGES) {
+                req->r_request->pages = req->r_data.pages;
+                req->r_request->page_count = req->r_data.num_pages;
+                req->r_request->page_alignment = req->r_data.alignment;
 #ifdef CONFIG_BLOCK
-        req->r_request->bio = req->r_data.bio;
+        } else if (req->r_data.type == CEPH_OSD_DATA_TYPE_BIO) {
+                req->r_request->bio = req->r_data.bio;
 #endif
+        } else {
+                pr_err("unknown request data type %d\n", req->r_data.type);
+        }
         req->r_request->trail = &req->r_trail;
 
         register_request(osdc, req);
@@ -1944,6 +1951,7 @@ int ceph_osdc_readpages(struct ceph_osd_client *osdc,
                 return PTR_ERR(req);
 
         /* it may be a short read due to an object boundary */
+        req->r_data.type = CEPH_OSD_DATA_TYPE_PAGES;
         req->r_data.pages = pages;
         req->r_data.num_pages = calc_pages_for(page_align, *plen);
         req->r_data.alignment = page_align;
@@ -1987,6 +1995,7 @@ int ceph_osdc_writepages(struct ceph_osd_client *osdc, struct ceph_vino vino,
                 return PTR_ERR(req);
 
         /* it may be a short write due to an object boundary */
+        req->r_data.type = CEPH_OSD_DATA_TYPE_PAGES;
         req->r_data.pages = pages;
         req->r_data.num_pages = calc_pages_for(page_align, len);
         req->r_data.alignment = page_align;
@@ -2083,23 +2092,30 @@ static struct ceph_msg *get_reply(struct ceph_connection *con,
         m = ceph_msg_get(req->r_reply);
 
         if (data_len > 0) {
-                int want = calc_pages_for(req->r_data.alignment, data_len);
-
-                if (req->r_data.pages && unlikely(req->r_data.num_pages < want)) {
-                        pr_warning("tid %lld reply has %d bytes %d pages, we"
-                                   " had only %d pages ready\n", tid, data_len,
-                                   want, req->r_data.num_pages);
-                        *skip = 1;
-                        ceph_msg_put(m);
-                        m = NULL;
-                        goto out;
-                }
-                m->pages = req->r_data.pages;
-                m->page_count = req->r_data.num_pages;
-                m->page_alignment = req->r_data.alignment;
+                if (req->r_data.type == CEPH_OSD_DATA_TYPE_PAGES) {
+                        int want;
+
+                        want = calc_pages_for(req->r_data.alignment, data_len);
+                        if (req->r_data.pages &&
+                                unlikely(req->r_data.num_pages < want)) {
+
+                                pr_warning("tid %lld reply has %d bytes %d "
+                                        "pages, we had only %d pages ready\n",
+                                        tid, data_len, want,
+                                        req->r_data.num_pages);
+                                *skip = 1;
+                                ceph_msg_put(m);
+                                m = NULL;
+                                goto out;
+                        }
+                        m->pages = req->r_data.pages;
+                        m->page_count = req->r_data.num_pages;
+                        m->page_alignment = req->r_data.alignment;
 #ifdef CONFIG_BLOCK
-                m->bio = req->r_data.bio;
+                } else if (req->r_data.type == CEPH_OSD_DATA_TYPE_BIO) {
+                        m->bio = req->r_data.bio;
 #endif
+                }
         }
         *skip = 0;
         req->r_con_filling_msg = con->ops->get(con);