If we encounter an error on a page, we can lose the error if we've
dropped the mmap_sem while we wait for the I/O. That can result in
taking the fault multiple times, and retrying the read multiple times.
Spotted by inspection.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Fixes: 6b4c9f446981 ("filemap: drop the mmap_sem for all blocking operations")
diff --git a/mm/filemap.c b/mm/filemap.c
index d0cf700bf201..37bd4aedfccf 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2615,6 +2615,8 @@ vm_fault_t filemap_fault(struct vm_fault *vmf)
if (!PageUptodate(page))
error = -EIO;
}
+ if (error < 0)
+ ret |= VM_FAULT_SIGBUS;
if (fpin)
goto out_retry;
put_page(page);
@@ -2622,9 +2624,9 @@ vm_fault_t filemap_fault(struct vm_fault *vmf)
if (!error || error == AOP_TRUNCATED_PAGE)
goto retry_find;
- /* Things didn't work out. Return zero to tell the mm layer so. */
+ /* Things didn't work out. */
shrink_readahead_size_eio(file, ra);
- return VM_FAULT_SIGBUS;
+ return ret;
out_retry:
/*
