1 files changed, 33 insertions, 16 deletions

diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index 4cb69925d8d9..8aa51e7a6a7d 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -269,6 +269,7 @@ int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
                 ubi_err("error %d while writing %d bytes to PEB %d:%d, written "
                         "%zd bytes", err, len, pnum, offset, written);
                 ubi_dbg_dump_stack();
+                ubi_dbg_dump_flash(ubi, pnum, offset, len);
         } else
                 ubi_assert(written == len);
 
@@ -475,30 +476,46 @@ out:
  */
 static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
 {
-        int err;
+        int err, err1;
         size_t written;
         loff_t addr;
         uint32_t data = 0;
+        struct ubi_vid_hdr vid_hdr;
 
-        addr = (loff_t)pnum * ubi->peb_size;
+        addr = (loff_t)pnum * ubi->peb_size + ubi->vid_hdr_aloffset;
         err = ubi->mtd->write(ubi->mtd, addr, 4, &written, (void *)&data);
-        if (err) {
-                ubi_err("error %d while writing 4 bytes to PEB %d:%d, written "
-                        "%zd bytes", err, pnum, 0, written);
-                ubi_dbg_dump_stack();
-                return err;
+        if (!err) {
+                addr -= ubi->vid_hdr_aloffset;
+                err = ubi->mtd->write(ubi->mtd, addr, 4, &written,
+                                      (void *)&data);
+                if (!err)
+                        return 0;
         }
 
-        addr += ubi->vid_hdr_aloffset;
-        err = ubi->mtd->write(ubi->mtd, addr, 4, &written, (void *)&data);
-        if (err) {
-                ubi_err("error %d while writing 4 bytes to PEB %d:%d, written "
-                        "%zd bytes", err, pnum, ubi->vid_hdr_aloffset, written);
-                ubi_dbg_dump_stack();
-                return err;
-        }
+        /*
+         * We failed to write to the media. This was observed with Spansion
+         * S29GL512N NOR flash. Most probably the eraseblock erasure was
+         * interrupted at a very inappropriate moment, so it became unwritable.
+         * In this case we probably anyway have garbage in this PEB.
+         */
+        err1 = ubi_io_read_vid_hdr(ubi, pnum, &vid_hdr, 0);
+        if (err1 == UBI_IO_BAD_VID_HDR)
+                /*
+                 * The VID header is corrupted, so we can safely erase this
+                 * PEB and not afraid that it will be treated as a valid PEB in
+                 * case of an unclean reboot.
+                 */
+                return 0;
 
-        return 0;
+        /*
+         * The PEB contains a valid VID header, but we cannot invalidate it.
+         * Supposedly the flash media or the driver is screwed up, so return an
+         * error.
+         */
+        ubi_err("cannot invalidate PEB %d, write returned %d read returned %d",
+                pnum, err, err1);
+        ubi_dbg_dump_flash(ubi, pnum, 0, ubi->peb_size);
+        return -EIO;
 }
 
 /**