From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Eric Van Hensbergen <ericvh@gmail.com>,
Ron Minnich <rminnich@sandia.gov>,
Latchesar Ionkov <lucho@ionkov.net>,
Steve French <sfrench@samba.org>,
Matthew Wilcox <mawilcox@microsoft.com>,
Ross Zwisler <ross.zwisler@linux.intel.com>,
Trond Myklebust <trond.myklebust@primarydata.com>,
Anna Schumaker <anna.schumaker@netapp.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jan Kara <jack@suse.cz>, Jens Axboe <axboe@kernel.dk>,
Johannes Weiner <hannes@cmpxchg.org>,
Alexey Kuznetsov <kuznet@virtuozzo.com>,
Christoph Hellwig <hch@lst.de>,
v9fs-developer@lists.sourceforge.net,
linux-kernel@vger.kernel.org, linux-cifs@vger.kernel.org,
samba-t
Subject: Re: [PATCH 1/4] fs: fix data invalidation in the cleancache during direct IO
Date: Tue, 18 Apr 2017 13:38:08 -0600 [thread overview]
Message-ID: <20170418193808.GA16667@linux.intel.com> (raw)
In-Reply-To: <20170414140753.16108-2-aryabinin@virtuozzo.com>
On Fri, Apr 14, 2017 at 05:07:50PM +0300, Andrey Ryabinin wrote:
> Some direct write fs hooks call invalidate_inode_pages2[_range]()
> conditionally iff mapping->nrpages is not zero. If page cache is empty,
> buffered read following after direct IO write would get stale data from
> the cleancache.
>
> Also it doesn't feel right to check only for ->nrpages because
> invalidate_inode_pages2[_range] invalidates exceptional entries as well.
>
> Fix this by calling invalidate_inode_pages2[_range]() regardless of nrpages
> state.
>
> Fixes: c515e1fd361c ("mm/fs: add hooks to support cleancache")
> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
> ---
<>
> diff --git a/fs/dax.c b/fs/dax.c
> index 2e382fe..1e8cca0 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -1047,7 +1047,7 @@ dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
> * into page tables. We have to tear down these mappings so that data
> * written by write(2) is visible in mmap.
> */
> - if ((iomap->flags & IOMAP_F_NEW) && inode->i_mapping->nrpages) {
> + if ((iomap->flags & IOMAP_F_NEW)) {
> invalidate_inode_pages2_range(inode->i_mapping,
> pos >> PAGE_SHIFT,
> (end - 1) >> PAGE_SHIFT);
tl;dr: I think the old code is correct, and that you don't need this change.
This should be harmless, but could slow us down a little if we keep
calling invalidate_inode_pages2_range() without really needing to. Really for
DAX I think we need to call invalidate_inode_page2_range() only if we have
zero pages mapped over the place where we are doing I/O, which is why we check
nrpages.
Is DAX even allowed to be used at the same time as cleancache? From a brief
look at Documentation/vm/cleancache.txt, it seems like these two features are
incompatible. With DAX we already are avoiding the page cache completely.
Anyway, I don't see how this change in DAX can save us from a data corruption
(which is what you're seeing, right?), and I think it could slow us down, so
I'd prefer to leave things as they are.
WARNING: multiple messages have this Message-ID (diff)
From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Eric Van Hensbergen <ericvh@gmail.com>,
Ron Minnich <rminnich@sandia.gov>,
Latchesar Ionkov <lucho@ionkov.net>,
Steve French <sfrench@samba.org>,
Matthew Wilcox <mawilcox@microsoft.com>,
Ross Zwisler <ross.zwisler@linux.intel.com>,
Trond Myklebust <trond.myklebust@primarydata.com>,
Anna Schumaker <anna.schumaker@netapp.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jan Kara <jack@suse.cz>, Jens Axboe <axboe@kernel.dk>,
Johannes Weiner <hannes@cmpxchg.org>,
Alexey Kuznetsov <kuznet@virtuozzo.com>,
Christoph Hellwig <hch@lst.de>,
v9fs-developer@lists.sourceforge.net,
linux-kernel@vger.kernel.org, linux-cifs@vger.kernel.org,
samba-technical@lists.samba.org, linux-nfs@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH 1/4] fs: fix data invalidation in the cleancache during direct IO
Date: Tue, 18 Apr 2017 13:38:08 -0600 [thread overview]
Message-ID: <20170418193808.GA16667@linux.intel.com> (raw)
In-Reply-To: <20170414140753.16108-2-aryabinin@virtuozzo.com>
On Fri, Apr 14, 2017 at 05:07:50PM +0300, Andrey Ryabinin wrote:
> Some direct write fs hooks call invalidate_inode_pages2[_range]()
> conditionally iff mapping->nrpages is not zero. If page cache is empty,
> buffered read following after direct IO write would get stale data from
> the cleancache.
>
> Also it doesn't feel right to check only for ->nrpages because
> invalidate_inode_pages2[_range] invalidates exceptional entries as well.
>
> Fix this by calling invalidate_inode_pages2[_range]() regardless of nrpages
> state.
>
> Fixes: c515e1fd361c ("mm/fs: add hooks to support cleancache")
> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
> ---
<>
> diff --git a/fs/dax.c b/fs/dax.c
> index 2e382fe..1e8cca0 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -1047,7 +1047,7 @@ dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
> * into page tables. We have to tear down these mappings so that data
> * written by write(2) is visible in mmap.
> */
> - if ((iomap->flags & IOMAP_F_NEW) && inode->i_mapping->nrpages) {
> + if ((iomap->flags & IOMAP_F_NEW)) {
> invalidate_inode_pages2_range(inode->i_mapping,
> pos >> PAGE_SHIFT,
> (end - 1) >> PAGE_SHIFT);
tl;dr: I think the old code is correct, and that you don't need this change.
This should be harmless, but could slow us down a little if we keep
calling invalidate_inode_pages2_range() without really needing to. Really for
DAX I think we need to call invalidate_inode_page2_range() only if we have
zero pages mapped over the place where we are doing I/O, which is why we check
nrpages.
Is DAX even allowed to be used at the same time as cleancache? From a brief
look at Documentation/vm/cleancache.txt, it seems like these two features are
incompatible. With DAX we already are avoiding the page cache completely.
Anyway, I don't see how this change in DAX can save us from a data corruption
(which is what you're seeing, right?), and I think it could slow us down, so
I'd prefer to leave things as they are.
WARNING: multiple messages have this Message-ID (diff)
From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Eric Van Hensbergen <ericvh@gmail.com>,
Ron Minnich <rminnich@sandia.gov>,
Latchesar Ionkov <lucho@ionkov.net>,
Steve French <sfrench@samba.org>,
Matthew Wilcox <mawilcox@microsoft.com>,
Ross Zwisler <ross.zwisler@linux.intel.com>,
Trond Myklebust <trond.myklebust@primarydata.com>,
Anna Schumaker <anna.schumaker@netapp.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jan Kara <jack@suse.cz>, Jens Axboe <axboe@kernel.dk>,
Johannes Weiner <hannes@cmpxchg.org>,
Alexey Kuznetsov <kuznet@virtuozzo.com>,
Christoph Hellwig <hch@lst.de>,
v9fs-developer@lists.sourceforge.net,
linux-kernel@vger.kernel.org, linux-cifs@vger.kernel.org,
samba-technical@lists.samba.org, linux-nfs@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH 1/4] fs: fix data invalidation in the cleancache during direct IO
Date: Tue, 18 Apr 2017 13:38:08 -0600 [thread overview]
Message-ID: <20170418193808.GA16667@linux.intel.com> (raw)
In-Reply-To: <20170414140753.16108-2-aryabinin@virtuozzo.com>
On Fri, Apr 14, 2017 at 05:07:50PM +0300, Andrey Ryabinin wrote:
> Some direct write fs hooks call invalidate_inode_pages2[_range]()
> conditionally iff mapping->nrpages is not zero. If page cache is empty,
> buffered read following after direct IO write would get stale data from
> the cleancache.
>
> Also it doesn't feel right to check only for ->nrpages because
> invalidate_inode_pages2[_range] invalidates exceptional entries as well.
>
> Fix this by calling invalidate_inode_pages2[_range]() regardless of nrpages
> state.
>
> Fixes: c515e1fd361c ("mm/fs: add hooks to support cleancache")
> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
> ---
<>
> diff --git a/fs/dax.c b/fs/dax.c
> index 2e382fe..1e8cca0 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -1047,7 +1047,7 @@ dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
> * into page tables. We have to tear down these mappings so that data
> * written by write(2) is visible in mmap.
> */
> - if ((iomap->flags & IOMAP_F_NEW) && inode->i_mapping->nrpages) {
> + if ((iomap->flags & IOMAP_F_NEW)) {
> invalidate_inode_pages2_range(inode->i_mapping,
> pos >> PAGE_SHIFT,
> (end - 1) >> PAGE_SHIFT);
tl;dr: I think the old code is correct, and that you don't need this change.
This should be harmless, but could slow us down a little if we keep
calling invalidate_inode_pages2_range() without really needing to. Really for
DAX I think we need to call invalidate_inode_page2_range() only if we have
zero pages mapped over the place where we are doing I/O, which is why we check
nrpages.
Is DAX even allowed to be used at the same time as cleancache? From a brief
look at Documentation/vm/cleancache.txt, it seems like these two features are
incompatible. With DAX we already are avoiding the page cache completely.
Anyway, I don't see how this change in DAX can save us from a data corruption
(which is what you're seeing, right?), and I think it could slow us down, so
I'd prefer to leave things as they are.
--
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next prev parent reply other threads:[~2017-04-18 19:38 UTC|newest]
Thread overview: 144+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-14 14:07 [PATCH 0/4] Properly invalidate data in the cleancache Andrey Ryabinin
2017-04-14 14:07 ` Andrey Ryabinin
2017-04-14 14:07 ` Andrey Ryabinin
2017-04-14 14:07 ` Andrey Ryabinin
2017-04-14 14:07 ` [PATCH 1/4] fs: fix data invalidation in the cleancache during direct IO Andrey Ryabinin
2017-04-14 14:07 ` Andrey Ryabinin
2017-04-14 14:07 ` Andrey Ryabinin
2017-04-18 19:38 ` Ross Zwisler [this message]
2017-04-18 19:38 ` Ross Zwisler
2017-04-18 19:38 ` Ross Zwisler
2017-04-19 15:11 ` Andrey Ryabinin
2017-04-19 15:11 ` Andrey Ryabinin
2017-04-19 15:11 ` Andrey Ryabinin
2017-04-19 19:28 ` Ross Zwisler
2017-04-19 19:28 ` Ross Zwisler
[not found] ` <20170419192836.GA6364-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2017-04-20 14:35 ` Jan Kara
2017-04-20 14:35 ` Jan Kara
2017-04-20 14:35 ` Jan Kara
[not found] ` <20170420143510.GF22135-4I4JzKEfoa/jFM9bn6wA6Q@public.gmane.org>
2017-04-20 14:44 ` Jan Kara
2017-04-20 14:44 ` Jan Kara
2017-04-20 14:44 ` Jan Kara
2017-04-20 19:14 ` Ross Zwisler
2017-04-20 19:14 ` Ross Zwisler
2017-04-21 3:44 ` [PATCH 1/2] dax: prevent invalidation of mapped DAX entries Ross Zwisler
2017-04-21 3:44 ` Ross Zwisler
2017-04-21 3:44 ` Ross Zwisler
2017-04-21 3:44 ` Ross Zwisler
2017-04-21 3:44 ` Ross Zwisler
2017-04-21 3:44 ` [PATCH 2/2] dax: fix data corruption due to stale mmap reads Ross Zwisler
2017-04-21 3:44 ` Ross Zwisler
2017-04-21 3:44 ` Ross Zwisler
2017-04-21 3:44 ` Ross Zwisler
2017-04-21 3:44 ` Ross Zwisler
2017-04-25 11:10 ` Jan Kara
2017-04-25 11:10 ` Jan Kara
2017-04-25 11:10 ` Jan Kara
2017-04-25 11:10 ` Jan Kara
2017-04-25 11:10 ` Jan Kara
2017-04-25 22:59 ` Ross Zwisler
2017-04-25 22:59 ` Ross Zwisler
2017-04-25 22:59 ` Ross Zwisler
2017-04-25 22:59 ` Ross Zwisler
2017-04-25 22:59 ` Ross Zwisler
2017-04-26 8:52 ` Jan Kara
2017-04-26 8:52 ` Jan Kara
2017-04-26 8:52 ` Jan Kara
2017-04-26 8:52 ` Jan Kara
2017-04-26 8:52 ` Jan Kara
2017-04-26 22:52 ` Ross Zwisler
2017-04-26 22:52 ` Ross Zwisler
2017-04-26 22:52 ` Ross Zwisler
2017-04-26 22:52 ` Ross Zwisler
2017-04-26 22:52 ` Ross Zwisler
2017-04-27 7:26 ` Jan Kara
2017-04-27 7:26 ` Jan Kara
2017-04-27 7:26 ` Jan Kara
2017-04-27 7:26 ` Jan Kara
2017-04-27 7:26 ` Jan Kara
2017-05-01 22:38 ` Ross Zwisler
2017-05-01 22:38 ` Ross Zwisler
2017-05-01 22:38 ` Ross Zwisler
2017-05-01 22:38 ` Ross Zwisler
2017-05-01 22:38 ` Ross Zwisler
2017-05-04 9:12 ` Jan Kara
2017-05-04 9:12 ` Jan Kara
2017-05-04 9:12 ` Jan Kara
2017-05-04 9:12 ` Jan Kara
2017-05-01 22:59 ` Dan Williams
2017-05-01 22:59 ` Dan Williams
2017-05-01 22:59 ` Dan Williams
2017-05-01 22:59 ` Dan Williams
2017-05-01 22:59 ` Dan Williams
2017-04-24 17:49 ` [PATCH 1/2] xfs: fix incorrect argument count check Ross Zwisler
2017-04-24 17:49 ` Ross Zwisler
2017-04-24 17:49 ` Ross Zwisler
2017-04-24 17:49 ` [PATCH 2/2] dax: add regression test for stale mmap reads Ross Zwisler
2017-04-24 17:49 ` Ross Zwisler
2017-04-24 17:49 ` Ross Zwisler
2017-04-25 11:27 ` Eryu Guan
2017-04-25 11:27 ` Eryu Guan
2017-04-25 11:27 ` Eryu Guan
2017-04-25 20:39 ` Ross Zwisler
2017-04-25 20:39 ` Ross Zwisler
2017-04-25 20:39 ` Ross Zwisler
2017-04-26 3:42 ` Eryu Guan
2017-04-26 3:42 ` Eryu Guan
2017-04-26 3:42 ` Eryu Guan
2017-04-25 10:10 ` [PATCH 1/2] dax: prevent invalidation of mapped DAX entries Jan Kara
2017-04-25 10:10 ` Jan Kara
2017-04-25 10:10 ` Jan Kara
2017-04-25 10:10 ` Jan Kara
2017-04-25 10:10 ` Jan Kara
2017-05-01 16:54 ` Ross Zwisler
2017-05-01 16:54 ` Ross Zwisler
2017-05-01 16:54 ` Ross Zwisler
2017-05-01 16:54 ` Ross Zwisler
2017-05-01 16:54 ` Ross Zwisler
[not found] ` <20170414140753.16108-2-aryabinin-5HdwGun5lf+gSpxsJD1C4w@public.gmane.org>
2017-04-18 22:46 ` [PATCH 1/4] fs: fix data invalidation in the cleancache during direct IO Andrew Morton
2017-04-18 22:46 ` Andrew Morton
2017-04-18 22:46 ` Andrew Morton
2017-04-18 22:46 ` Andrew Morton
2017-04-19 15:15 ` Andrey Ryabinin
2017-04-19 15:15 ` Andrey Ryabinin
2017-04-19 15:15 ` Andrey Ryabinin
2017-04-14 14:07 ` [PATCH 2/4] fs/block_dev: always invalidate cleancache in invalidate_bdev() Andrey Ryabinin
2017-04-14 14:07 ` Andrey Ryabinin
2017-04-14 14:07 ` Andrey Ryabinin
2017-04-18 18:51 ` Nikolay Borisov
2017-04-18 18:51 ` Nikolay Borisov
2017-04-19 13:22 ` Andrey Ryabinin
2017-04-19 13:22 ` Andrey Ryabinin
2017-04-19 13:22 ` Andrey Ryabinin
2017-04-14 14:07 ` [PATCH 3/4] mm/truncate: bail out early from invalidate_inode_pages2_range() if mapping is empty Andrey Ryabinin
2017-04-14 14:07 ` Andrey Ryabinin
2017-04-14 14:07 ` Andrey Ryabinin
2017-04-14 14:07 ` [PATCH 4/4] mm/truncate: avoid pointless cleancache_invalidate_inode() calls Andrey Ryabinin
2017-04-14 14:07 ` Andrey Ryabinin
2017-04-14 14:07 ` Andrey Ryabinin
[not found] ` <20170414140753.16108-1-aryabinin-5HdwGun5lf+gSpxsJD1C4w@public.gmane.org>
2017-04-18 15:24 ` [PATCH 0/4] Properly invalidate data in the cleancache Konrad Rzeszutek Wilk
2017-04-18 15:24 ` Konrad Rzeszutek Wilk
2017-04-18 15:24 ` Konrad Rzeszutek Wilk
2017-04-24 16:41 ` [PATCH v2 " Andrey Ryabinin
2017-04-24 16:41 ` Andrey Ryabinin
2017-04-24 16:41 ` Andrey Ryabinin
2017-04-24 16:41 ` [PATCH v2 1/4] fs: fix data invalidation in the cleancache during direct IO Andrey Ryabinin
2017-04-24 16:41 ` Andrey Ryabinin
2017-04-24 16:41 ` Andrey Ryabinin
2017-04-25 8:25 ` Jan Kara
2017-04-25 8:25 ` Jan Kara
2017-04-24 16:41 ` [PATCH v2 2/4] fs/block_dev: always invalidate cleancache in invalidate_bdev() Andrey Ryabinin
2017-04-24 16:41 ` Andrey Ryabinin
2017-04-24 16:41 ` Andrey Ryabinin
2017-04-25 8:34 ` Jan Kara
2017-04-25 8:34 ` Jan Kara
2017-04-24 16:41 ` [PATCH v2 3/4] mm/truncate: bail out early from invalidate_inode_pages2_range() if mapping is empty Andrey Ryabinin
2017-04-24 16:41 ` Andrey Ryabinin
2017-04-24 16:41 ` Andrey Ryabinin
2017-04-25 8:37 ` Jan Kara
2017-04-25 8:37 ` Jan Kara
2017-04-24 16:41 ` [PATCH v2 4/4] mm/truncate: avoid pointless cleancache_invalidate_inode() calls Andrey Ryabinin
2017-04-24 16:41 ` Andrey Ryabinin
2017-04-24 16:41 ` Andrey Ryabinin
2017-04-25 8:41 ` Jan Kara
2017-04-25 8:41 ` Jan Kara
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