1 files changed, 24 insertions, 0 deletions

diff --git a/fs/dax.c b/fs/dax.c
index c22eaf162f95..9187f3b07f3e 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -859,6 +859,7 @@ int dax_writeback_mapping_range(struct address_space *mapping,
                         if (ret < 0)
                                 goto out;
                 }
+                start_index = indices[pvec.nr - 1] + 1;
         }
 out:
         put_dax(dax_dev);
@@ -1155,6 +1156,17 @@ static int dax_iomap_pte_fault(struct vm_fault *vmf,
         }
 
         /*
+         * It is possible, particularly with mixed reads & writes to private
+         * mappings, that we have raced with a PMD fault that overlaps with
+         * the PTE we need to set up.  If so just return and the fault will be
+         * retried.
+         */
+        if (pmd_trans_huge(*vmf->pmd) || pmd_devmap(*vmf->pmd)) {
+                vmf_ret = VM_FAULT_NOPAGE;
+                goto unlock_entry;
+        }
+
+        /*
          * Note that we don't bother to use iomap_apply here: DAX required
          * the file system block size to be equal the page size, which means
          * that we never have to deal with more than a single extent here.
@@ -1398,6 +1410,18 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf,
                 goto fallback;
 
         /*
+         * It is possible, particularly with mixed reads & writes to private
+         * mappings, that we have raced with a PTE fault that overlaps with
+         * the PMD we need to set up.  If so just return and the fault will be
+         * retried.
+         */
+        if (!pmd_none(*vmf->pmd) && !pmd_trans_huge(*vmf->pmd) &&
+                        !pmd_devmap(*vmf->pmd)) {
+                result = 0;
+                goto unlock_entry;
+        }
+
+        /*
          * Note that we don't use iomap_apply here.  We aren't doing I/O, only
          * setting up a mapping, so really we're using iomap_begin() as a way
          * to look up our filesystem block.