If above is true, then may be we should not call
"SetPageUptodate(page)", in case of an error reading block bitmap?
Thoughts?
Yeah, it's better to set page uptodate only if all block bitmap buffers
are uptodate represent by this page.
So I guess the *easier* thing to do here is to abort the loop which
calls ext4_wait_block_bitmap() in ext4_mb_init_cache, similar to how
the loop above it does (which calls for ext4_read_block_bitmap_nowait())
Since if any of the block bitmap buffer (which belongs to that page)
could not be read properly, then we should not set the PageUptodate.
(including for blocksize < pagesize where groups_per_page > 1) and
no need of even setting up the in memory buddy and bitmap information
(since we are anyway not going to use it).
Others can comment, if something else needs to be done?
But I think over optimizing this logic for blocksize < pagesize
may become an overkill? (since this mostly happens during an I/O error).
Ok, so as I see this bug was possibly introduced to handle blocksize <
pagesize case itself [1]. So it will make no sense to just optimize it
for blocksize == pagesize again. So I guess we should look into this
more closely rather then simply implementing above logic.
[1]: https://www.spinics.net/lists/linux-ext4/msg48111.html
So, I can get back to this some time later maybe.
-ritesh
