[PATCH 4/6] jffs2: add write verification to NOR direct write paths
zhouminqiang
zhouminqiang2 at huawei.com
Thu Aug 20 03:50:00 PDT 2026
NOR Flash and other non-writebuffered devices write directly through
jffs2_flash_direct_writev() and jffs2_flash_direct_write() without
any write-back verification. If mtd_write() succeeds but the readable
medium differs from JFFS2's source buffer, a later node CRC failure
cannot distinguish transport/program-time corruption from post-commit
media damage.
Move jffs2_verify_write() from wbuf.c to writev.c so it can be
shared by both writebuffered and direct write paths. Add
jffs2_verify_writev() to iterate over kvec entries and verify each
one individually. In both direct write functions, add mtd_write()
return value and retlen checks, and invoke verification after
a successful complete write.
Signed-off-by: zhouminqiang <zhouminqiang2 at huawei.com>
---
fs/jffs2/os-linux.h | 11 ++++
fs/jffs2/wbuf.c | 69 -------------------------
fs/jffs2/writev.c | 122 ++++++++++++++++++++++++++++++++++++++++++--
3 files changed, 130 insertions(+), 72 deletions(-)
diff --git a/fs/jffs2/os-linux.h b/fs/jffs2/os-linux.h
index 86ab014a349c..e73ef643fd97 100644
--- a/fs/jffs2/os-linux.h
+++ b/fs/jffs2/os-linux.h
@@ -192,6 +192,17 @@ int jffs2_flash_direct_writev(struct jffs2_sb_info *c, const struct kvec *vecs,
int jffs2_flash_direct_write(struct jffs2_sb_info *c, loff_t ofs, size_t len,
size_t *retlen, const u_char *buf);
+#ifdef CONFIG_JFFS2_FS_WBUF_VERIFY
+int jffs2_verify_write(struct jffs2_sb_info *c, const unsigned char *buf,
+ uint32_t ofs, size_t len);
+int jffs2_verify_writev(struct jffs2_sb_info *c,
+ const struct kvec *vecs,
+ unsigned long count, loff_t to);
+#else
+#define jffs2_verify_write(c, b, o, l) (0)
+#define jffs2_verify_writev(c, v, cnt, t) (0)
+#endif
+
#endif /* __JFFS2_OS_LINUX_H__ */
diff --git a/fs/jffs2/wbuf.c b/fs/jffs2/wbuf.c
index 3e99587f40e4..493be5765c47 100644
--- a/fs/jffs2/wbuf.c
+++ b/fs/jffs2/wbuf.c
@@ -15,7 +15,6 @@
#include <linux/kernel.h>
#include <linux/slab.h>
-#include <linux/vmalloc.h>
#include <linux/mtd/mtd.h>
#include <linux/crc32.h>
#include <linux/mtd/rawnand.h>
@@ -227,74 +226,6 @@ static struct jffs2_raw_node_ref **jffs2_incore_replace_raw(struct jffs2_sb_info
return NULL;
}
-#ifdef CONFIG_JFFS2_FS_WBUF_VERIFY
-static int jffs2_verify_write(struct jffs2_sb_info *c, unsigned char *buf,
- uint32_t ofs, size_t len)
-{
- int ret = 0;
- size_t retlen, i;
- char *eccstr;
- void *verify_buf;
-
- verify_buf = __vmalloc(len, GFP_NOFS);
- if (!verify_buf) {
- pr_warn("%s(): verify buffer allocation failed, skipping verification\n",
- __func__);
- return 0;
- }
-
- ret = mtd_read(c->mtd, ofs, len, &retlen, verify_buf);
- if (ret && ret != -EUCLEAN && ret != -EBADMSG) {
- pr_warn("%s(): Read back of page at %08x failed: %d\n",
- __func__, ofs, ret);
- goto out_free;
- } else if (retlen != len) {
- pr_warn("%s(): Read back of page at %08x gave short read: %zu not %zu\n",
- __func__, ofs, retlen, len);
- ret = -EIO;
- goto out_free;
- }
-
- for (i = 0; i < len; i++) {
- uint8_t c1 = ((uint8_t *)buf)[i];
- uint8_t c2 = ((uint8_t *)verify_buf)[i];
- int dump_len;
-
- if (c1 == c2)
- continue;
-
- if (ret == -EUCLEAN)
- eccstr = "corrected";
- else if (ret == -EBADMSG)
- eccstr = "correction failed";
- else
- eccstr = "OK or unused";
-
- dump_len = min_t(int, 128, len - i);
- pr_warn("Write verify error (ECC %s) at %08x (+%zu/%zu). Wrote:\n",
- eccstr, ofs, i, len);
- print_hex_dump(KERN_WARNING, "", DUMP_PREFIX_OFFSET, 16, 1,
- buf + i, dump_len, 0);
-
- pr_warn("Read back:\n");
- print_hex_dump(KERN_WARNING, "", DUMP_PREFIX_OFFSET, 16, 1,
- verify_buf + i, dump_len, 0);
-
- ret = -EIO;
- goto out_free;
- }
-
- vfree(verify_buf);
- return 0;
-
-out_free:
- vfree(verify_buf);
- return ret;
-}
-#else
-#define jffs2_verify_write(c,b,o,l) (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. */
diff --git a/fs/jffs2/writev.c b/fs/jffs2/writev.c
index a1bda9dab3f8..39adc15ffd69 100644
--- a/fs/jffs2/writev.c
+++ b/fs/jffs2/writev.c
@@ -10,12 +10,100 @@
*/
#include <linux/kernel.h>
+#include <linux/vmalloc.h>
#include <linux/mtd/mtd.h>
#include "nodelist.h"
+#ifdef CONFIG_JFFS2_FS_WBUF_VERIFY
+int jffs2_verify_write(struct jffs2_sb_info *c, const unsigned char *buf,
+ uint32_t ofs, size_t len)
+{
+ int ret = 0;
+ size_t retlen, i;
+ char *eccstr;
+ void *verify_buf;
+
+ verify_buf = __vmalloc(len, GFP_NOFS);
+ if (!verify_buf) {
+ pr_warn("%s(): verify buffer allocation failed, skipping verification\n",
+ __func__);
+ return 0;
+ }
+
+ ret = mtd_read(c->mtd, ofs, len, &retlen, verify_buf);
+ if (ret && ret != -EUCLEAN && ret != -EBADMSG) {
+ pr_warn("%s(): Read back of page at %08x failed: %d\n",
+ __func__, ofs, ret);
+ goto out_free;
+ } else if (retlen != len) {
+ pr_warn("%s(): Read back of page at %08x gave short read: %zu not %zu\n",
+ __func__, ofs, retlen, len);
+ ret = -EIO;
+ goto out_free;
+ }
+
+ for (i = 0; i < len; i++) {
+ uint8_t c1 = ((uint8_t *)buf)[i];
+ uint8_t c2 = ((uint8_t *)verify_buf)[i];
+ int dump_len;
+
+ if (c1 == c2)
+ continue;
+
+ if (ret == -EUCLEAN)
+ eccstr = "corrected";
+ else if (ret == -EBADMSG)
+ eccstr = "correction failed";
+ else
+ eccstr = "OK or unused";
+
+ dump_len = min_t(int, 128, len - i);
+ pr_warn("Write verify error (ECC %s) at %08x (+%zu/%zu). Wrote:\n",
+ eccstr, ofs, i, len);
+ print_hex_dump(KERN_WARNING, "", DUMP_PREFIX_OFFSET, 16, 1,
+ buf + i, dump_len, 0);
+
+ pr_warn("Read back:\n");
+ print_hex_dump(KERN_WARNING, "", DUMP_PREFIX_OFFSET, 16, 1,
+ verify_buf + i, dump_len, 0);
+
+ ret = -EIO;
+ goto out_free;
+ }
+
+ vfree(verify_buf);
+ return 0;
+
+out_free:
+ vfree(verify_buf);
+ return ret;
+}
+
+int jffs2_verify_writev(struct jffs2_sb_info *c,
+ const struct kvec *vecs,
+ unsigned long count, loff_t to)
+{
+ loff_t ofs = to;
+ unsigned long i;
+ int ret;
+
+ for (i = 0; i < count; i++) {
+ if (!vecs[i].iov_len)
+ continue;
+ ret = jffs2_verify_write(c, vecs[i].iov_base, ofs,
+ vecs[i].iov_len);
+ if (ret)
+ return ret;
+ ofs += vecs[i].iov_len;
+ }
+ return 0;
+}
+#endif /* CONFIG_JFFS2_FS_WBUF_VERIFY */
+
int jffs2_flash_direct_writev(struct jffs2_sb_info *c, const struct kvec *vecs,
unsigned long count, loff_t to, size_t *retlen)
{
+ int ret;
if (!jffs2_is_writebuffered(c)) {
if (jffs2_sum_active()) {
int res;
@@ -26,15 +114,31 @@ int jffs2_flash_direct_writev(struct jffs2_sb_info *c, const struct kvec *vecs,
}
}
- return mtd_writev(c->mtd, vecs, count, to, retlen);
+ ret = mtd_writev(c->mtd, vecs, count, to, retlen);
+
+ if (ret) {
+ pr_warn("%s(): Write failed with %d\n", __func__, ret);
+ } else {
+ size_t totlen = 0;
+ unsigned long i;
+
+ for (i = 0; i < count; i++)
+ totlen += vecs[i].iov_len;
+ if (*retlen != totlen) {
+ pr_warn("%s(): Write was short: %zu instead of %zu\n",
+ __func__, *retlen, totlen);
+ ret = -EIO;
+ } else
+ ret = jffs2_verify_writev(c, vecs, count, to);
+ }
+
+ return ret;
}
int jffs2_flash_direct_write(struct jffs2_sb_info *c, loff_t ofs, size_t len,
size_t *retlen, const u_char *buf)
{
int ret;
- ret = mtd_write(c->mtd, ofs, len, retlen, buf);
-
if (jffs2_sum_active()) {
struct kvec vecs[1];
int res;
@@ -47,5 +151,17 @@ int jffs2_flash_direct_write(struct jffs2_sb_info *c, loff_t ofs, size_t len,
return res;
}
}
+
+ ret = mtd_write(c->mtd, ofs, len, retlen, buf);
+
+ if (ret) {
+ pr_warn("%s(): Write failed with %d\n", __func__, ret);
+ } else if (*retlen != len) {
+ pr_warn("%s(): Write was short: %zu instead of %zu\n",
+ __func__, *retlen, len);
+ ret = -EIO;
+ } else
+ ret = jffs2_verify_write(c, buf, ofs, len);
+
return ret;
}
--
2.52.0
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