LU-13805 llite: unaligned direct_rw_pages

[fs/lustre-release.git] / lustre / llite / rw26.c

diff --git a/lustre/llite/rw26.c b/lustre/llite/rw26.c
index 3a5c85d..ed009f8 100644 (file)
--- a/lustre/llite/rw26.c
+++ b/lustre/llite/rw26.c
@@ -372,20 +372,23 @@ ll_direct_rw_pages(const struct lu_env *env, struct cl_io *io, size_t size,
        struct cl_sync_io *anchor = &sdio->csd_sync;
        loff_t offset   = pv->ldp_file_offset;
        int io_pages    = 0;
-       int i;
        ssize_t rc = 0;
+       int i = 0;
 
        ENTRY;
 
        cl_2queue_init(queue);
-       for (i = 0; i < pv->ldp_count; i++) {
-               LASSERT(!(offset & (PAGE_SIZE - 1)));
+       while (size > 0) {
+               size_t from = offset & ~PAGE_MASK;
+               size_t to = min(from + size, PAGE_SIZE);
+
                page = cl_page_find(env, obj, offset >> PAGE_SHIFT,
                                    pv->ldp_pages[i], CPT_TRANSIENT);
                if (IS_ERR(page)) {
                        rc = PTR_ERR(page);
                        break;
                }
+
                LASSERT(page->cp_type == CPT_TRANSIENT);
                rc = cl_page_own(env, io, page);
                if (rc) {
@@ -409,16 +412,24 @@ ll_direct_rw_pages(const struct lu_env *env, struct cl_io *io, size_t size,
                 */
                cl_page_list_add(&queue->c2_qin, page, false);
                /*
-                * Set page clip to tell transfer formation engine
-                * that page has to be sent even if it is beyond KMS.
+                * Call page clip for incomplete pages, to set range of bytes
+                * in the page and to tell transfer formation engine to send
+                * the page even if it is beyond KMS (ie, don't trim IO to KMS)
                 */
-               if (size < PAGE_SIZE)
-                       cl_page_clip(env, page, 0, size);
+               if (from != 0 || to != PAGE_SIZE)
+                       cl_page_clip(env, page, from, to);
                ++io_pages;
+               i++;
 
-               offset += PAGE_SIZE;
-               size -= PAGE_SIZE;
+               offset += to - from;
+               size -= to - from;
        }
+       /* on success, we should hit every page in the pvec and have no bytes
+        * left in 'size'
+        */
+       LASSERT(ergo(rc == 0, i == pv->ldp_count));
+       LASSERT(ergo(rc == 0, size == 0));
+
        if (rc == 0 && io_pages > 0) {
                int iot = rw == READ ? CRT_READ : CRT_WRITE;