[JFFS2] Add support for write-buffer verification.

We've seen some evil corruption issues, where the corruption seems to be
introduced after the JFFS2 crc32 is calculated but before the NAND
controller calculates the ECC. So it's in RAM or in the PCI DMA
transfer; not on the flash. Attempt to catch it earlier by (optionally)
reading back from the flash immediately after writing it.

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

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/jffs2/jffs2_fs_sb.h b/fs/jffs2/jffs2_fs_sb.h
index b13298a824ed..ae99cd7fd43b 100644
--- a/fs/jffs2/jffs2_fs_sb.h
+++ b/fs/jffs2/jffs2_fs_sb.h
@@ -106,6 +106,9 @@ struct jffs2_sb_info {
 
         uint32_t wbuf_pagesize; /* 0 for NOR and other flashes with no wbuf */
 
+#ifdef CONFIG_JFFS2_FS_WBUF_VERIFY
+        unsigned char *wbuf_verify; /* read-back buffer for verification */
+#endif
 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
         unsigned char *wbuf; /* Write-behind buffer for NAND flash */
         uint32_t wbuf_ofs;