pnfsblock: fix NULL pointer dereference

bl_add_page_to_bio returns error pointer. bio should be reset to
NULL in failure cases as the out path always calls bl_submit_bio.

Signed-off-by: Peng Tao <peng_tao@emc.com>
Signed-off-by: Jim Rees <rees@umich.edu>
Cc: stable@kernel.org [3.0]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index 2167ba2afdbb..4ddbfbf1c3ad 100644
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -292,6 +292,7 @@ bl_read_pagelist(struct nfs_read_data *rdata)
                                                  bl_end_io_read, par);
                         if (IS_ERR(bio)) {
                                 rdata->pnfs_error = PTR_ERR(bio);
+                                bio = NULL;
                                 goto out;
                         }
                 }
@@ -581,6 +582,7 @@ fill_invalid_ext:
                                                  bl_end_io_write_zero, par);
                         if (IS_ERR(bio)) {
                                 wdata->pnfs_error = PTR_ERR(bio);
+                                bio = NULL;
                                 goto out;
                         }
                         /* FIXME: This should be done in bi_end_io */
@@ -629,6 +631,7 @@ next_page:
                                          bl_end_io_write, par);
                 if (IS_ERR(bio)) {
                         wdata->pnfs_error = PTR_ERR(bio);
+                        bio = NULL;
                         goto out;
                 }
                 isect += PAGE_CACHE_SECTORS;