LU-14616 readahead: fix reserving for unaliged read

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

diff --git a/lustre/llite/vvp_io.c b/lustre/llite/vvp_io.c
index c001d85..b014b4f 100644 (file)
--- a/lustre/llite/vvp_io.c
+++ b/lustre/llite/vvp_io.c
@@ -813,6 +813,7 @@ static int vvp_io_read_start(const struct lu_env *env,
        int exceed = 0;
        int result;
        struct iov_iter iter;
+       pgoff_t page_offset;
 
        ENTRY;
 
@@ -857,14 +858,20 @@ static int vvp_io_read_start(const struct lu_env *env,
        if (!vio->vui_ra_valid) {
                vio->vui_ra_valid = true;
                vio->vui_ra_start_idx = cl_index(obj, pos);
-               vio->vui_ra_pages = cl_index(obj, tot + PAGE_SIZE - 1);
-               /* If both start and end are unaligned, we read one more page
-                * than the index math suggests. */
-               if ((pos & ~PAGE_MASK) != 0 && ((pos + tot) & ~PAGE_MASK) != 0)
+               vio->vui_ra_pages = 0;
+               page_offset = pos & ~PAGE_MASK;
+               if (page_offset) {
                        vio->vui_ra_pages++;
+                       if (tot > PAGE_SIZE - page_offset)
+                               tot -= (PAGE_SIZE - page_offset);
+                       else
+                               tot = 0;
+               }
+               vio->vui_ra_pages += (tot + PAGE_SIZE - 1) >> PAGE_SHIFT;
 
                CDEBUG(D_READA, "tot %zu, ra_start %lu, ra_count %lu\n",
-                      tot, vio->vui_ra_start_idx, vio->vui_ra_pages);
+                      vio->vui_tot_count, vio->vui_ra_start_idx,
+                      vio->vui_ra_pages);
        }
 
        /* BUG: 5972 */