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LU-5263 llite: update ras stride offset
[fs/lustre-release.git] / lustre / llite / rw.c
index 8ea255a..4aab3d1 100644 (file)
@@ -474,10 +474,11 @@ static int ll_read_ahead_pages(const struct lu_env *env,
                         /* FIXME: This assertion only is valid when it is for
                          * forward read-ahead, it will be fixed when backward
                          * read-ahead is implemented */
-                        LASSERTF(page_idx > ria->ria_stoff, "Invalid page_idx %lu"
-                                "rs %lu re %lu ro %lu rl %lu rp %lu\n", page_idx,
-                                ria->ria_start, ria->ria_end, ria->ria_stoff,
-                                ria->ria_length, ria->ria_pages);
+                       LASSERTF(page_idx >= ria->ria_stoff,
+                               "Invalid page_idx %lu rs %lu re %lu ro %lu "
+                               "rl %lu rp %lu\n", page_idx,
+                               ria->ria_start, ria->ria_end, ria->ria_stoff,
+                               ria->ria_length, ria->ria_pages);
                         offset = page_idx - ria->ria_stoff;
                         offset = offset % (ria->ria_length);
                         if (offset > ria->ria_pages) {
@@ -538,11 +539,23 @@ int ll_readahead(const struct lu_env *env, struct cl_io *io,
                 ras->ras_window_len = bead->lrr_start + bead->lrr_count -
                                       ras->ras_window_start;
         }
-        /* Reserve a part of the read-ahead window that we'll be issuing */
-        if (ras->ras_window_len) {
-                start = ras->ras_next_readahead;
-                end = ras->ras_window_start + ras->ras_window_len - 1;
-        }
+       /* Reserve a part of the read-ahead window that we'll be issuing */
+       if (ras->ras_window_len > 0) {
+               /*
+                * Note: other thread might rollback the ras_next_readahead,
+                * if it can not get the full size of prepared pages, see the
+                * end of this function. For stride read ahead, it needs to
+                * make sure the offset is no less than ras_stride_offset,
+                * so that stride read ahead can work correctly.
+                */
+               if (stride_io_mode(ras))
+                       start = max(ras->ras_next_readahead,
+                                   ras->ras_stride_offset);
+               else
+                       start = ras->ras_next_readahead;
+               end = ras->ras_window_start + ras->ras_window_len - 1;
+       }
+
         if (end != 0) {
                 unsigned long rpc_boundary;
                 /*