[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>
diff --git a/fs/jffs2/wbuf.c b/fs/jffs2/wbuf.c
index 64f8d7a..ec99c8e 100644
--- a/fs/jffs2/wbuf.c
+++ b/fs/jffs2/wbuf.c
@@ -220,6 +220,47 @@
return NULL;
}
+#ifdef CONFIG_JFFS2_FS_WBUF_VERIFY
+static int jffs2_verify_write(struct jffs2_sb_info *c, unsigned char *buf,
+ uint32_t ofs)
+{
+ int ret;
+ size_t retlen;
+ char *eccstr;
+
+ ret = c->mtd->read(c->mtd, ofs, c->wbuf_pagesize, &retlen, c->wbuf_verify);
+ if (ret && ret != -EUCLEAN && ret != -EBADMSG) {
+ printk(KERN_WARNING "jffs2_verify_write(): Read back of page at %08x failed: %d\n", c->wbuf_ofs, ret);
+ return ret;
+ } else if (retlen != c->wbuf_pagesize) {
+ printk(KERN_WARNING "jffs2_verify_write(): Read back of page at %08x gave short read: %zd not %d.\n", ofs, retlen, c->wbuf_pagesize);
+ return -EIO;
+ }
+ if (!memcmp(buf, c->wbuf_verify, c->wbuf_pagesize))
+ return 0;
+
+ if (ret == -EUCLEAN)
+ eccstr = "corrected";
+ else if (ret == -EBADMSG)
+ eccstr = "correction failed";
+ else
+ eccstr = "OK or unused";
+
+ printk(KERN_WARNING "Write verify error (ECC %s) at %08x. Wrote:\n",
+ eccstr, c->wbuf_ofs);
+ print_hex_dump(KERN_WARNING, "", DUMP_PREFIX_OFFSET, 16, 1,
+ c->wbuf, c->wbuf_pagesize, 0);
+
+ printk(KERN_WARNING "Read back:\n");
+ print_hex_dump(KERN_WARNING, "", DUMP_PREFIX_OFFSET, 16, 1,
+ c->wbuf_verify, c->wbuf_pagesize, 0);
+
+ return -EIO;
+}
+#else
+#define jffs2_verify_write(c,b,o) (0)
+#endif
+
/* Recover from failure to write wbuf. Recover the nodes up to the
* wbuf, not the one which we were starting to try to write. */
@@ -380,7 +421,7 @@
ret = c->mtd->write(c->mtd, ofs, towrite, &retlen,
rewrite_buf);
- if (ret || retlen != towrite) {
+ if (ret || retlen != towrite || jffs2_verify_write(c, rewrite_buf, ofs)) {
/* Argh. We tried. Really we did. */
printk(KERN_CRIT "Recovery of wbuf failed due to a second write error\n");
kfree(buf);
@@ -587,15 +628,16 @@
ret = c->mtd->write(c->mtd, c->wbuf_ofs, c->wbuf_pagesize, &retlen, c->wbuf);
- if (ret || retlen != c->wbuf_pagesize) {
- if (ret)
- printk(KERN_WARNING "jffs2_flush_wbuf(): Write failed with %d\n",ret);
- else {
- printk(KERN_WARNING "jffs2_flush_wbuf(): Write was short: %zd instead of %d\n",
- retlen, c->wbuf_pagesize);
- ret = -EIO;
- }
-
+ if (ret) {
+ printk(KERN_WARNING "jffs2_flush_wbuf(): Write failed with %d\n", ret);
+ goto wfail;
+ } else if (retlen != c->wbuf_pagesize) {
+ printk(KERN_WARNING "jffs2_flush_wbuf(): Write was short: %zd instead of %d\n",
+ retlen, c->wbuf_pagesize);
+ ret = -EIO;
+ goto wfail;
+ } else if ((ret = jffs2_verify_write(c, c->wbuf, c->wbuf_ofs))) {
+ wfail:
jffs2_wbuf_recover(c);
return ret;
@@ -1138,11 +1180,22 @@
return -ENOMEM;
}
+#ifdef CONFIG_JFFS2_FS_WBUF_VERIFY
+ c->wbuf_verify = kmalloc(c->wbuf_pagesize, GFP_KERNEL);
+ if (!c->wbuf_verify) {
+ kfree(c->oobbuf);
+ kfree(c->wbuf);
+ return -ENOMEM;
+ }
+#endif
return 0;
}
void jffs2_nand_flash_cleanup(struct jffs2_sb_info *c)
{
+#ifdef CONFIG_JFFS2_FS_WBUF_VERIFY
+ kfree(c->wbuf_verify);
+#endif
kfree(c->wbuf);
kfree(c->oobbuf);
}