dax: fallback from pmd to pte on error
In preparation for consulting a badblocks list in pmem_direct_access(),
teach dax_pmd_fault() to fallback rather than fail immediately upon
encountering an error. The thought being that reducing the span of the
dax request may avoid the error region.
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
diff --git a/fs/dax.c b/fs/dax.c
index 9bc6624..d602410 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -855,8 +855,8 @@
long length = dax_map_atomic(bdev, &dax);
if (length < 0) {
- result = VM_FAULT_SIGBUS;
- goto out;
+ dax_pmd_dbg(&bh, address, "dax-error fallback");
+ goto fallback;
}
if (length < PMD_SIZE) {
dax_pmd_dbg(&bh, address, "dax-length too small");