[PATCH v2] UBIFS: Fix assert failed in ubifs_set_page_dirty
hujianyang at huawei.com
Sat May 3 23:38:35 PDT 2014
On 2014/4/30 21:48, Dolev Raviv wrote:
> Hi Hujianyang and Laurence,
> I'm hitting an assertion in very similar code during the callback
> ubifs_releasepage(). I'm quite new to this code area, and currently diving
> in to understanding the race you described (before I attempt to look at
> the patch).
> I was wondering if this assertion is related?
> [ 862.695278] UBIFS assert failed in ubifs_releasepage at 1434 (pid 11088)
What's your kernel version? Because in v3.15 and v3.10, line 1434
present different assertion.
I think you probably hit:
static int ubifs_releasepage(struct page *page, gfp_t unused_gfp_flags)
* An attempt to release a dirty page without budgeting for it - should
* not happen.
ubifs_assert(0); <- v3.10 line 1434
Page_Private bit seems to indicate page is budgeted in UBIFS. Dropping
caches performs with page lock and just deals with pages which are not
dirty. Then, if page_private bit is set, vfs performs ->releasepage at
Maybe some explanation of this assert failed is that there is a private
(budgeted) but not dirty page in your page caches.
I think it is not related to my race because pages can just remain
in 3 states at fsync and mmap:
1) Dirty, Private
2) Not Dirty, Not Private
3) Dirty, Not Private (wrong condition)
Did you get some more assert failed after this? If you umount UBIFS,
ubifs_put_super will check the budget info, and I think you should
hit some assertion there.
Do you have a simply way to reproduce this assert failed?
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