UBI: avoid program operation on NOR flash after erasure interrupted

nor_erase_prepare() will be called before erase a NOR flash, it will program '0' into a block to mark this block. But program data into a erasure interrupted block can cause program timtout(several minutes at most) error, could impact other operation on NOR flash. So UBIFS can read this block first to avoid unneeded program operation. This patch try to put read operation at head of write operation in nor_erase_prepare(), read out the data. If the data is already corrupt, then no need to program any data into this block, just go to erase this block. This patch is validated on Micron NOR flash, part number is：JS28F512M29EWHA Signed-off-by: Qi Wang <qiwang@micron.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UBI: avoid program operation on NOR flash after erasure interrupted
nor_erase_prepare() will be called before erase a NOR flash, it will program '0' into a block to mark this block. But program data into a erasure interrupted block can cause program timtout(several minutes at most) error, could impact other operation on NOR flash. So UBIFS can read this block first to avoid unneeded program operation. This patch try to put read operation at head of write operation in nor_erase_prepare(), read out the data. If the data is already corrupt, then no need to program any data into this block, just go to erase this block. This patch is validated on Micron NOR flash, part number is：JS28F512M29EWHA Signed-off-by: Qi Wang <qiwang@micron.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Qi Wang 王起 (qiwang) · Artem Bityutskiy
1 parent b6b44e0ad2
Showing 1 changed file with 22 additions and 32 deletions Side-by-side Diff
drivers/mtd/ubi/io.c
@@ -495,10 +495,12 @@
  */
 static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
 {
-	int err, err1;
+	int err;
 	size_t written;
 	loff_t addr;
 	uint32_t data = 0;
+	struct ubi_ec_hdr ec_hdr;
+
 	/*
 	 * Note, we cannot generally define VID header buffers on stack,
 	 * because of the way we deal with these buffers (see the header
  
  
  
  
  
  
  
@@ -509,50 +511,38 @@
 	struct ubi_vid_hdr vid_hdr;
  
 	/*
+	 * If VID or EC is valid, we have to corrupt them before erasing.
 	 * It is important to first invalidate the EC header, and then the VID
 	 * header. Otherwise a power cut may lead to valid EC header and
 	 * invalid VID header, in which case UBI will treat this PEB as
 	 * corrupted and will try to preserve it, and print scary warnings.
 	 */
 	addr = (loff_t)pnum * ubi->peb_size;
-	err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
-	if (!err) {
-		addr += ubi->vid_hdr_aloffset;
+	err = ubi_io_read_ec_hdr(ubi, pnum, &ec_hdr, 0);
+	if (err != UBI_IO_BAD_HDR_EBADMSG && err != UBI_IO_BAD_HDR &&
+	    err != UBI_IO_FF){
 		err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
-		if (!err)
-			return 0;
+		if(err)
+			goto error;
 	}
  
-	/*
-	 * We failed to write to the media. This was observed with Spansion
-	 * S29GL512N NOR flash. Most probably the previously 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_HDR_EBADMSG || err1 == UBI_IO_BAD_HDR ||
-	    err1 == UBI_IO_FF) {
-		struct ubi_ec_hdr ec_hdr;
-
-		err1 = ubi_io_read_ec_hdr(ubi, pnum, &ec_hdr, 0);
-		if (err1 == UBI_IO_BAD_HDR_EBADMSG || err1 == UBI_IO_BAD_HDR ||
-		    err1 == UBI_IO_FF)
-			/*
-			 * Both VID and EC headers are 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;
+	err = ubi_io_read_vid_hdr(ubi, pnum, &vid_hdr, 0);
+	if (err != UBI_IO_BAD_HDR_EBADMSG && err != UBI_IO_BAD_HDR &&
+	    err != UBI_IO_FF){
+		addr += ubi->vid_hdr_aloffset;
+		err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
+		if (err)
+			goto error;
 	}
+	return 0;
  
+error:
 	/*
-	 * 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.
+	 * The PEB contains a valid VID or EC 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_err("cannot invalidate PEB %d, write returned %d", pnum, err);
 	ubi_dump_flash(ubi, pnum, 0, ubi->peb_size);
 	return -EIO;
 }
...	...	@@ -495,10 +495,12 @@
495	495	*/
496	496	static int nor_erase_prepare(struct ubi_device *ubi, int pnum)
497	497	{
498		- int err, err1;
	498	+ int err;
499	499	size_t written;
500	500	loff_t addr;
501	501	uint32_t data = 0;
	502	+ struct ubi_ec_hdr ec_hdr;
	503	+
502	504	/*
503	505	* Note, we cannot generally define VID header buffers on stack,
504	506	* because of the way we deal with these buffers (see the header
505	507
506	508
507	509
508	510
509	511
510	512
511	513
...	...	@@ -509,50 +511,38 @@
509	511	struct ubi_vid_hdr vid_hdr;
510	512
511	513	/*
	514	+ * If VID or EC is valid, we have to corrupt them before erasing.
512	515	* It is important to first invalidate the EC header, and then the VID
513	516	* header. Otherwise a power cut may lead to valid EC header and
514	517	* invalid VID header, in which case UBI will treat this PEB as
515	518	* corrupted and will try to preserve it, and print scary warnings.
516	519	*/
517	520	addr = (loff_t)pnum * ubi->peb_size;
518		- err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
519		- if (!err) {
520		- addr += ubi->vid_hdr_aloffset;
	521	+ err = ubi_io_read_ec_hdr(ubi, pnum, &ec_hdr, 0);
	522	+ if (err != UBI_IO_BAD_HDR_EBADMSG && err != UBI_IO_BAD_HDR &&
	523	+ err != UBI_IO_FF){
521	524	err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
522		- if (!err)
523		- return 0;
	525	+ if(err)
	526	+ goto error;
524	527	}
525	528
526		- /*
527		- * We failed to write to the media. This was observed with Spansion
528		- * S29GL512N NOR flash. Most probably the previously eraseblock erasure
529		- * was interrupted at a very inappropriate moment, so it became
530		- * unwritable. In this case we probably anyway have garbage in this
531		- * PEB.
532		- */
533		- err1 = ubi_io_read_vid_hdr(ubi, pnum, &vid_hdr, 0);
534		- if (err1 == UBI_IO_BAD_HDR_EBADMSG \|\| err1 == UBI_IO_BAD_HDR \|\|
535		- err1 == UBI_IO_FF) {
536		- struct ubi_ec_hdr ec_hdr;
537		-
538		- err1 = ubi_io_read_ec_hdr(ubi, pnum, &ec_hdr, 0);
539		- if (err1 == UBI_IO_BAD_HDR_EBADMSG \|\| err1 == UBI_IO_BAD_HDR \|\|
540		- err1 == UBI_IO_FF)
541		- /*
542		- * Both VID and EC headers are corrupted, so we can
543		- * safely erase this PEB and not afraid that it will be
544		- * treated as a valid PEB in case of an unclean reboot.
545		- */
546		- return 0;
	529	+ err = ubi_io_read_vid_hdr(ubi, pnum, &vid_hdr, 0);
	530	+ if (err != UBI_IO_BAD_HDR_EBADMSG && err != UBI_IO_BAD_HDR &&
	531	+ err != UBI_IO_FF){
	532	+ addr += ubi->vid_hdr_aloffset;
	533	+ err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data);
	534	+ if (err)
	535	+ goto error;
547	536	}
	537	+ return 0;
548	538
	539	+error:
549	540	/*
550		- * The PEB contains a valid VID header, but we cannot invalidate it.
551		- * Supposedly the flash media or the driver is screwed up, so return an
552		- * error.
	541	+ * The PEB contains a valid VID or EC header, but we cannot invalidate
	542	+ * it. Supposedly the flash media or the driver is screwed up, so
	543	+ * return an error.
553	544	*/
554		- ubi_err("cannot invalidate PEB %d, write returned %d read returned %d",
555		- pnum, err, err1);
	545	+ ubi_err("cannot invalidate PEB %d, write returned %d", pnum, err);
556	546	ubi_dump_flash(ubi, pnum, 0, ubi->peb_size);
557	547	return -EIO;
558	548	}