[JFFS2] Fix data CRC checking on NOR flash.

We were failing to check the data CRC on data nodes on non-writebuffered
flash, which led to "interesting" behaviour on unclean shutdowns.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

1 files changed, 15 insertions, 14 deletions

diff --git a/fs/jffs2/readinode.c b/fs/jffs2/readinode.c
index 2eae5d2dbeb..da22da95459 100644
--- a/fs/jffs2/readinode.c
+++ b/fs/jffs2/readinode.c
@@ -37,23 +37,24 @@ static int check_node_data(struct jffs2_sb_info *c, struct jffs2_tmp_dnode_info
 
         BUG_ON(tn->csize == 0);
 
-        if (!jffs2_is_writebuffered(c))
-                goto adj_acc;
-
         /* Calculate how many bytes were already checked */
         ofs = ref_offset(ref) + sizeof(struct jffs2_raw_inode);
-        len = ofs % c->wbuf_pagesize;
-        if (likely(len))
-                len = c->wbuf_pagesize - len;
-
-        if (len >= tn->csize) {
-                dbg_readinode("no need to check node at %#08x, data length %u, data starts at %#08x - it has already been checked.\n",
-                        ref_offset(ref), tn->csize, ofs);
-                goto adj_acc;
-        }
+        len = tn->csize;
+
+        if (jffs2_is_writebuffered(c)) {
+                int adj = ofs % c->wbuf_pagesize;
+                if (likely(adj))
+                        adj = c->wbuf_pagesize - adj;
+
+                if (adj >= tn->csize) {
+                        dbg_readinode("no need to check node at %#08x, data length %u, data starts at %#08x - it has already been checked.\n",
+                                      ref_offset(ref), tn->csize, ofs);
+                        goto adj_acc;
+                }
 
-        ofs += len;
-        len = tn->csize - len;
+                ofs += adj;
+                len -= adj;
+        }
 
         dbg_readinode("check node at %#08x, data length %u, partial CRC %#08x, correct CRC %#08x, data starts at %#08x, start checking from %#08x - %u bytes.\n",
                 ref_offset(ref), tn->csize, tn->partial_crc, tn->data_crc, ofs - len, ofs, len);