From: Daniel McNeil <daniel@osdl.org>
To: Andrew Morton <akpm@osdl.org>
Cc: Suparna Bhattacharya <suparna@in.ibm.com>,
janetmor@us.ibm.com, Badari Pulavarty <pbadari@us.ibm.com>,
"linux-aio@kvack.org" <linux-aio@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: [PATCH linux-2.6.1-rc1-mm1] filemap_fdatawait.patch
Date: 31 Dec 2003 14:34:21 -0800 [thread overview]
Message-ID: <1072910061.712.67.camel@ibm-c.pdx.osdl.net> (raw)
In-Reply-To: <20031231031736.0416808f.akpm@osdl.org>
[-- Attachment #1: Type: text/plain, Size: 1375 bytes --]
The other potential race in filemap_fdatawait() was that it
removed the page from the locked list while waiting for a writeback
and if there was a 2nd filemap_fdatawait() running on another cpu,
it would not wait for the page being written since it would never see
it on the list.
I've been running with filemap_fdatawait() that waits for the
locked page and writeback with the page still on the locked list.
Any other filemap_fdatawait() would see the page being written
and then wait.
I've re-diffed this patch against 2.6.1-rc1-mm1.
Thoughts?
Daniel
On Wed, 2003-12-31 at 03:17, Andrew Morton wrote:
> Andrew Morton <akpm@osdl.org> wrote:
> >
> > Let me actually think about this a bit.
>
> Nasty. The same race is present in 2.4.x...
>
> How's about we start new I/O in filemap_fdatawait() if the page is dirty?
>
>
> diff -puN mm/filemap.c~a mm/filemap.c
> --- 25/mm/filemap.c~a 2003-12-31 03:10:29.000000000 -0800
> +++ 25-akpm/mm/filemap.c 2003-12-31 03:17:05.000000000 -0800
> @@ -206,7 +206,13 @@ restart:
> page_cache_get(page);
> spin_unlock(&mapping->page_lock);
>
> - wait_on_page_writeback(page);
> + lock_page(page);
> + if (PageDirty(page) && mapping->a_ops->writepage) {
> + write_one_page(page, 1);
> + } else {
> + wait_on_page_writeback(page);
> + unlock_page(page);
> + }
> if (PageError(page))
> ret = -EIO;
>
>
[-- Attachment #2: linux-2.6.1-rc1-mm1.fdatawait.patch --]
[-- Type: text/plain, Size: 1131 bytes --]
--- linux-2.6.1-rc1-mm1/mm/filemap.c 2003-12-31 10:52:47.039988554 -0800
+++ linux-2.6.1-rc1-mm1.fdatawait/mm/filemap.c 2003-12-31 14:10:43.114197926 -0800
@@ -188,6 +188,32 @@ restart:
struct page *page;
page = list_entry(mapping->locked_pages.next,struct page,list);
+ /*
+ * If the page is locked, it might be in process of being
+ * setup for writeback but without PG_writeback set
+ * and with PG_dirty cleared.
+ * (PG_dirty is cleared BEFORE PG_writeback is set)
+ * So, wait for the PG_locked to clear, then start over.
+ */
+ if (PageLocked(page)) {
+ page_cache_get(page);
+ spin_unlock(&mapping->page_lock);
+ wait_on_page_locked(page);
+ page_cache_release(page);
+ goto restart;
+ }
+ /*
+ * Wait for page writeback with it still on the locked list.
+ */
+ if (PageWriteback(page)) {
+ page_cache_get(page);
+ spin_unlock(&mapping->page_lock);
+ wait_on_page_writeback(page);
+ if (PageError(page))
+ ret = -EIO;
+ page_cache_release(page);
+ goto restart;
+ }
list_del(&page->list);
if (PageDirty(page))
list_add(&page->list, &mapping->dirty_pages);
next prev parent reply other threads:[~2003-12-31 22:34 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <3FCD4B66.8090905@us.ibm.com>
2003-12-06 1:29 ` [PATCH linux-2.6.0-test10-mm1] dio-read-race-fix Daniel McNeil
2003-12-08 18:23 ` Daniel McNeil
2003-12-12 0:51 ` Daniel McNeil
2003-12-17 1:25 ` [PATCH linux-2.6.0-test10-mm1] filemap_fdatawait.patch Daniel McNeil
2003-12-17 2:03 ` Andrew Morton
2003-12-17 19:25 ` Daniel McNeil
2003-12-17 20:17 ` Janet Morgan
2003-12-31 9:18 ` Suparna Bhattacharya
2003-12-31 9:35 ` Andrew Morton
2003-12-31 9:55 ` Suparna Bhattacharya
2003-12-31 9:59 ` Andrew Morton
2003-12-31 10:09 ` Suparna Bhattacharya
2003-12-31 10:10 ` Andrew Morton
2003-12-31 10:48 ` Suparna Bhattacharya
2003-12-31 10:53 ` Andrew Morton
2003-12-31 10:54 ` Andrew Morton
2003-12-31 11:17 ` Andrew Morton
2003-12-31 22:34 ` Daniel McNeil [this message]
2003-12-31 22:41 ` [PATCH linux-2.6.1-rc1-mm1] aiodio_fallback_bio_count.patch Daniel McNeil
2003-12-31 23:46 ` Andrew Morton
2004-01-02 5:14 ` Suparna Bhattacharya
2004-01-02 7:46 ` Andrew Morton
2004-01-05 3:55 ` Suparna Bhattacharya
2004-01-05 5:06 ` Andrew Morton
2004-01-05 5:28 ` Suparna Bhattacharya
2004-01-05 5:28 ` Andrew Morton
2004-01-05 6:06 ` Suparna Bhattacharya
2004-01-05 6:14 ` Lincoln Dale
2003-12-31 22:47 ` [PATCH linux-2.6.1-rc1-mm1] dio_isize.patch Daniel McNeil
2003-12-31 23:42 ` [PATCH linux-2.6.1-rc1-mm1] filemap_fdatawait.patch Andrew Morton
2004-01-02 4:20 ` Suparna Bhattacharya
2004-01-02 4:36 ` Andrew Morton
2004-01-02 5:50 ` [PATCH linux-2.6.0-test10-mm1] filemap_fdatawait.patch Suparna Bhattacharya
2004-01-02 7:31 ` Andrew Morton
2004-01-05 13:49 ` Marcelo Tosatti
2004-01-05 20:27 ` Andrew Morton
2004-03-29 15:44 ` Marcelo Tosatti
2004-01-11 23:14 ` Janet Morgan
2004-01-11 23:44 ` Andrew Morton
2004-01-12 18:00 ` filemap_fdatawait.patch Daniel McNeil
2004-01-12 19:39 ` [PATCH linux-2.6.0-test10-mm1] filemap_fdatawait.patch Janet Morgan
2004-01-12 19:46 ` Daniel McNeil
2004-01-13 4:12 ` Janet Morgan
2003-12-30 4:53 ` [PATCH linux-2.6.0-test10-mm1] dio-read-race-fix Suparna Bhattacharya
2003-12-31 0:29 ` Daniel McNeil
2003-12-31 6:09 ` Suparna Bhattacharya
2004-01-08 23:55 ` Daniel McNeil
2004-01-09 3:55 ` Suparna Bhattacharya
2004-02-05 1:39 ` [PATCH 2.6.2-rc3-mm1] DIO read race fix Daniel McNeil
2004-02-05 1:54 ` Badari Pulavarty
2004-02-05 2:07 ` Andrew Morton
2004-02-05 2:54 ` Janet Morgan
2004-02-05 3:19 ` Andrew Morton
2004-02-05 3:43 ` Suparna Bhattacharya
2004-02-05 5:33 ` Andrew Morton
2004-02-05 17:52 ` Daniel McNeil
2004-02-05 18:53 ` Badari Pulavarty
2004-03-29 15:41 ` [PATCH linux-2.6.0-test10-mm1] dio-read-race-fix Suparna Bhattacharya
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