Commit 6afaf8a4 authored Nov 29, 2009 by Sebastian Andrzej Siewior Committed by Artem Bityutskiy Dec 04, 2009

UBI: flush wl before clearing update marker



ubiupdatevol -t does the following:
- ubi_start_update()
  - set_update_marker()
  - for all LEBs ubi_eba_unmap_leb()
  - clear_update_marker()
  - ubi_wl_flush()

ubi_wl_flush() physically erases all PEB, once it returns all PEBs are
empty. clear_update_marker() has the update marker written after return.
If there is a power cut between the last two functions then the UBI
volume has no longer the "update" marker set and may have some valid
LEBs while some of them may be gone.
If that volume in question happens to be a UBIFS volume, then mount
will fail with

|UBIFS error (pid 1361): ubifs_read_node: bad node type (255 but expected 6)
|UBIFS error (pid 1361): ubifs_read_node: bad node at LEB 0:0
|Not a node, first 24 bytes:
|00000000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff

if there is at least one valid LEB and the wear-leveling worker managed
to clear LEB 0.

The patch waits for the wl worker to finish prior clearing the "update"
marker on flash. The two new LEB which are scheduled for erasing after
clear_update_marker() should not matter because they are only visible to
UBI.

Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: stable@kernel.org

parent 949cb623

drivers/mtd/ubi/upd.c

+11 −9

Original line number	Diff line number	Diff line
		@@ -147,11 +147,13 @@ int ubi_start_update(struct ubi_device ubi, struct ubi_volume vol,
		}

		if (bytes == 0) {
		err = ubi_wl_flush(ubi);
		if (err)
		return err;

		err = clear_update_marker(ubi, vol, 0);
		if (err)
		return err;
		err = ubi_wl_flush(ubi);
		if (!err)
		vol->updating = 0;
		}

		@@ -362,17 +364,17 @@ int ubi_more_update_data(struct ubi_device ubi, struct ubi_volume vol,

		ubi_assert(vol->upd_received <= vol->upd_bytes);
		if (vol->upd_received == vol->upd_bytes) {
		err = ubi_wl_flush(ubi);
		if (err)
		return err;
		/* The update is finished, clear the update marker */
		err = clear_update_marker(ubi, vol, vol->upd_bytes);
		if (err)
		return err;
		err = ubi_wl_flush(ubi);
		if (err == 0) {
		vol->updating = 0;
		err = to_write;
		vfree(vol->upd_buf);
		}
		}

		return err;
		}

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