tree f32db3212e23a38c794df0c01fcf8505180ca51d
parent 949cb6232d5fc9fa77cfa441418e12d6f9de163e
author Sebastian Andrzej Siewior <sebastian@breakpoint.cc> 1259520362 +0100
committer Artem Bityutskiy <Artem.Bityutskiy@nokia.com> 1259905631 +0200

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