UBI: add ubi_leb_map interface
The idea of this interface belongs to Adrian Hunter. The
interface is extremely useful when one has to have a guarantee
that an LEB will contain all 0xFFs even in case of an unclean
reboot. UBI does have an 'ubi_leb_erase()' call which may do
this, but it is stupid and ineffecient, because it flushes whole
queue. I should be re-worked to just be a pair of unmap,
map calls.
The user of the interfaci is UBIFS at the moment.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
index 85f50c8..c87db07 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -656,11 +656,14 @@
goto write_error;
}
- err = ubi_io_write_data(ubi, buf, pnum, offset, len);
- if (err) {
- ubi_warn("failed to write %d bytes at offset %d of LEB %d:%d, "
- "PEB %d", len, offset, vol_id, lnum, pnum);
- goto write_error;
+ if (len) {
+ err = ubi_io_write_data(ubi, buf, pnum, offset, len);
+ if (err) {
+ ubi_warn("failed to write %d bytes at offset %d of "
+ "LEB %d:%d, PEB %d", len, offset, vol_id,
+ lnum, pnum);
+ goto write_error;
+ }
}
vol->eba_tbl[lnum] = pnum;
diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c
index 03c774f..e1ef802 100644
--- a/drivers/mtd/ubi/kapi.c
+++ b/drivers/mtd/ubi/kapi.c
@@ -547,6 +547,51 @@
EXPORT_SYMBOL_GPL(ubi_leb_unmap);
/**
+ * ubi_leb_map - map logical erasblock to a physical eraseblock.
+ * @desc: volume descriptor
+ * @lnum: logical eraseblock number
+ * @dtype: expected data type
+ *
+ * This function maps an un-mapped logical eraseblock @lnum to a physical
+ * eraseblock. This means, that after a successfull invocation of this
+ * function the logical eraseblock @lnum will be empty (contain only %0xFF
+ * bytes) and be mapped to a physical eraseblock, even if an unclean reboot
+ * happens.
+ *
+ * This function returns zero in case of success, %-EBADF if the volume is
+ * damaged because of an interrupted update, %-EBADMSG if the logical
+ * eraseblock is already mapped, and other negative error codes in case of
+ * other failures.
+ */
+int ubi_leb_map(struct ubi_volume_desc *desc, int lnum, int dtype)
+{
+ struct ubi_volume *vol = desc->vol;
+ struct ubi_device *ubi = vol->ubi;
+ int vol_id = vol->vol_id;
+
+ dbg_msg("unmap LEB %d:%d", vol_id, lnum);
+
+ if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
+ return -EROFS;
+
+ if (lnum < 0 || lnum >= vol->reserved_pebs)
+ return -EINVAL;
+
+ if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM &&
+ dtype != UBI_UNKNOWN)
+ return -EINVAL;
+
+ if (vol->upd_marker)
+ return -EBADF;
+
+ if (vol->eba_tbl[lnum] >= 0)
+ return -EBADMSG;
+
+ return ubi_eba_write_leb(ubi, vol_id, lnum, NULL, 0, 0, dtype);
+}
+EXPORT_SYMBOL_GPL(ubi_leb_map);
+
+/**
* ubi_is_mapped - check if logical eraseblock is mapped.
* @desc: volume descriptor
* @lnum: logical eraseblock number