[JFFS2] Fix data CRC checking on NOR flash.

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=92525726df0c30e080b0fce9b0eb699c622d261e
Commit:     92525726df0c30e080b0fce9b0eb699c622d261e
Parent:     8547e583a1140698cab41bc3f687efe8f8b2bb41
Author:     David Woodhouse <dwmw2 at infradead.org>
AuthorDate: Wed Nov 21 12:08:16 2007 -0500
Committer:  David Woodhouse <dwmw2 at infradead.org>
CommitDate: Wed Nov 21 12:08:16 2007 -0500

    [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 at infradead.org>
---
 fs/jffs2/readinode.c |   29 +++++++++++++++--------------
 1 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/fs/jffs2/readinode.c b/fs/jffs2/readinode.c
index 2eae5d2..da22da9 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);