From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Jan Kara <jack@suse.cz>
Cc: Latchesar Ionkov <lucho@ionkov.net>,
Trond Myklebust <trond.myklebust@primarydata.com>,
linux-mm@kvack.org, Christoph Hellwig <hch@lst.de>,
linux-cifs@vger.kernel.org,
Matthew Wilcox <mawilcox@microsoft.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Eric Van Hensbergen <ericvh@gmail.com>,
linux-nvdimm@lists.01.org,
Alexander Viro <viro@zeniv.linux.org.uk>,
v9fs-developer@lists.sourceforge.net,
Jens Axboe <axboe@kernel.dk>,
linux-nfs@vger.kernel.org,
"Darrick J. Wong" <darrick.wong@oracle.com>,
samba-technical@lists.samba.org, linux-kernel@vger.kernel.org,
Steve French <sfrench@samba.org>,
Alexey Kuznetsov <kuznet@virtuozzo.com>,
Johannes Weiner <hannes@cmpxchg.org>,
linux-fsdevel@vger.kernel.org, Ron Minnich <rminnich@sandia.gov>,
Andrew Morton <akpm@linux-foundation.org>,
Anna Schumaker <anna.schumaker@netapp.com>
Subject: Re: [PATCH v2 1/2] dax: prevent invalidation of mapped DAX entries
Date: Mon, 8 May 2017 11:08:36 -0600 [thread overview]
Message-ID: <20170508170836.GA19867@linux.intel.com> (raw)
In-Reply-To: <20170505072912.GA25424@quack2.suse.cz>
On Fri, May 05, 2017 at 09:29:12AM +0200, Jan Kara wrote:
> On Thu 04-05-17 13:59:09, Ross Zwisler wrote:
> > dax_invalidate_mapping_entry() currently removes DAX exceptional entries
> > only if they are clean and unlocked. This is done via:
> >
> > invalidate_mapping_pages()
> > invalidate_exceptional_entry()
> > dax_invalidate_mapping_entry()
> >
> > However, for page cache pages removed in invalidate_mapping_pages() there
> > is an additional criteria which is that the page must not be mapped. This
> > is noted in the comments above invalidate_mapping_pages() and is checked in
> > invalidate_inode_page().
> >
> > For DAX entries this means that we can can end up in a situation where a
> > DAX exceptional entry, either a huge zero page or a regular DAX entry,
> > could end up mapped but without an associated radix tree entry. This is
> > inconsistent with the rest of the DAX code and with what happens in the
> > page cache case.
> >
> > We aren't able to unmap the DAX exceptional entry because according to its
> > comments invalidate_mapping_pages() isn't allowed to block, and
> > unmap_mapping_range() takes a write lock on the mapping->i_mmap_rwsem.
> >
> > We could potentially do an rmap walk to see if each of the entries actually
> > has any active mappings before we remove it, but this might end up being
> > very expensive and doesn't currently look to be worth it.
> >
> > So, just remove dax_invalidate_mapping_entry() and leave the DAX entries in
> > the radix tree.
> >
> > Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
> > Fixes: c6dcf52c23d2 ("mm: Invalidate DAX radix tree entries only if appropriate")
> > Reported-by: Jan Kara <jack@suse.cz>
> > Reviewed-by: Jan Kara <jack@suse.cz>
> > Cc: <stable@vger.kernel.org> [4.10+]
>
> Ah, I've just sent out a series which contains these two patches and
> another two patches which change the entry locking to fix the last spotted
> race... So either just take my last two patches on top of these two or
> take my series as a whole.
Sounds good. You added a better comment in invalidate_inode_pages2_range(), so
let's just use your version of this series.
_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm
WARNING: multiple messages have this Message-ID (diff)
From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Jan Kara <jack@suse.cz>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Alexander Viro <viro@zeniv.linux.org.uk>,
Alexey Kuznetsov <kuznet@virtuozzo.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Anna Schumaker <anna.schumaker@netapp.com>,
Christoph Hellwig <hch@lst.de>,
Dan Williams <dan.j.williams@intel.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
Eric Van Hensbergen <ericvh@gmail.com>,
Jens Axboe <axboe@kernel.dk>,
Johannes Weiner <hannes@cmpxchg.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Latchesar Ionkov <lucho@ionkov.net>,
linux-cifs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, linux-nfs@vger.kernel.org,
linux-nvdimm@lists.01.org,
Matthew Wilcox <mawilcox@microsoft.com>,
Ron Minnich <rminnich@sandia.gov>,
samba-technical@lists.samba.org, Steve French <sfrench@samba.org>,
Tr
Subject: Re: [PATCH v2 1/2] dax: prevent invalidation of mapped DAX entries
Date: Mon, 8 May 2017 11:08:36 -0600 [thread overview]
Message-ID: <20170508170836.GA19867@linux.intel.com> (raw)
In-Reply-To: <20170505072912.GA25424@quack2.suse.cz>
On Fri, May 05, 2017 at 09:29:12AM +0200, Jan Kara wrote:
> On Thu 04-05-17 13:59:09, Ross Zwisler wrote:
> > dax_invalidate_mapping_entry() currently removes DAX exceptional entries
> > only if they are clean and unlocked. This is done via:
> >
> > invalidate_mapping_pages()
> > invalidate_exceptional_entry()
> > dax_invalidate_mapping_entry()
> >
> > However, for page cache pages removed in invalidate_mapping_pages() there
> > is an additional criteria which is that the page must not be mapped. This
> > is noted in the comments above invalidate_mapping_pages() and is checked in
> > invalidate_inode_page().
> >
> > For DAX entries this means that we can can end up in a situation where a
> > DAX exceptional entry, either a huge zero page or a regular DAX entry,
> > could end up mapped but without an associated radix tree entry. This is
> > inconsistent with the rest of the DAX code and with what happens in the
> > page cache case.
> >
> > We aren't able to unmap the DAX exceptional entry because according to its
> > comments invalidate_mapping_pages() isn't allowed to block, and
> > unmap_mapping_range() takes a write lock on the mapping->i_mmap_rwsem.
> >
> > We could potentially do an rmap walk to see if each of the entries actually
> > has any active mappings before we remove it, but this might end up being
> > very expensive and doesn't currently look to be worth it.
> >
> > So, just remove dax_invalidate_mapping_entry() and leave the DAX entries in
> > the radix tree.
> >
> > Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
> > Fixes: c6dcf52c23d2 ("mm: Invalidate DAX radix tree entries only if appropriate")
> > Reported-by: Jan Kara <jack@suse.cz>
> > Reviewed-by: Jan Kara <jack@suse.cz>
> > Cc: <stable@vger.kernel.org> [4.10+]
>
> Ah, I've just sent out a series which contains these two patches and
> another two patches which change the entry locking to fix the last spotted
> race... So either just take my last two patches on top of these two or
> take my series as a whole.
Sounds good. You added a better comment in invalidate_inode_pages2_range(), so
let's just use your version of this series.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
WARNING: multiple messages have this Message-ID (diff)
From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Jan Kara <jack@suse.cz>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Alexander Viro <viro@zeniv.linux.org.uk>,
Alexey Kuznetsov <kuznet@virtuozzo.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Anna Schumaker <anna.schumaker@netapp.com>,
Christoph Hellwig <hch@lst.de>,
Dan Williams <dan.j.williams@intel.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
Eric Van Hensbergen <ericvh@gmail.com>,
Jens Axboe <axboe@kernel.dk>,
Johannes Weiner <hannes@cmpxchg.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Latchesar Ionkov <lucho@ionkov.net>,
linux-cifs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, linux-nfs@vger.kernel.org,
linux-nvdimm@ml01.01.org, Matthew Wilcox <mawilcox@microsoft.com>,
Ron Minnich <rminnich@sandia.gov>,
samba-technical@lists.samba.org, Steve French <sfrench@samba.org>,
Trond Myklebust <trond.myklebust@primarydata.com>,
v9fs-developer@lists.sourceforge.net
Subject: Re: [PATCH v2 1/2] dax: prevent invalidation of mapped DAX entries
Date: Mon, 8 May 2017 11:08:36 -0600 [thread overview]
Message-ID: <20170508170836.GA19867@linux.intel.com> (raw)
In-Reply-To: <20170505072912.GA25424@quack2.suse.cz>
On Fri, May 05, 2017 at 09:29:12AM +0200, Jan Kara wrote:
> On Thu 04-05-17 13:59:09, Ross Zwisler wrote:
> > dax_invalidate_mapping_entry() currently removes DAX exceptional entries
> > only if they are clean and unlocked. This is done via:
> >
> > invalidate_mapping_pages()
> > invalidate_exceptional_entry()
> > dax_invalidate_mapping_entry()
> >
> > However, for page cache pages removed in invalidate_mapping_pages() there
> > is an additional criteria which is that the page must not be mapped. This
> > is noted in the comments above invalidate_mapping_pages() and is checked in
> > invalidate_inode_page().
> >
> > For DAX entries this means that we can can end up in a situation where a
> > DAX exceptional entry, either a huge zero page or a regular DAX entry,
> > could end up mapped but without an associated radix tree entry. This is
> > inconsistent with the rest of the DAX code and with what happens in the
> > page cache case.
> >
> > We aren't able to unmap the DAX exceptional entry because according to its
> > comments invalidate_mapping_pages() isn't allowed to block, and
> > unmap_mapping_range() takes a write lock on the mapping->i_mmap_rwsem.
> >
> > We could potentially do an rmap walk to see if each of the entries actually
> > has any active mappings before we remove it, but this might end up being
> > very expensive and doesn't currently look to be worth it.
> >
> > So, just remove dax_invalidate_mapping_entry() and leave the DAX entries in
> > the radix tree.
> >
> > Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
> > Fixes: c6dcf52c23d2 ("mm: Invalidate DAX radix tree entries only if appropriate")
> > Reported-by: Jan Kara <jack@suse.cz>
> > Reviewed-by: Jan Kara <jack@suse.cz>
> > Cc: <stable@vger.kernel.org> [4.10+]
>
> Ah, I've just sent out a series which contains these two patches and
> another two patches which change the entry locking to fix the last spotted
> race... So either just take my last two patches on top of these two or
> take my series as a whole.
Sounds good. You added a better comment in invalidate_inode_pages2_range(), so
let's just use your version of this series.
WARNING: multiple messages have this Message-ID (diff)
From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Jan Kara <jack@suse.cz>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Alexander Viro <viro@zeniv.linux.org.uk>,
Alexey Kuznetsov <kuznet@virtuozzo.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Anna Schumaker <anna.schumaker@netapp.com>,
Christoph Hellwig <hch@lst.de>,
Dan Williams <dan.j.williams@intel.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
Eric Van Hensbergen <ericvh@gmail.com>,
Jens Axboe <axboe@kernel.dk>,
Johannes Weiner <hannes@cmpxchg.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Latchesar Ionkov <lucho@ionkov.net>,
linux-cifs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, linux-nfs@vger.kernel.org,
linux-nvdimm@lists.01.org,
Matthew Wilcox <mawilcox@microsoft.com>,
Ron Minnich <rminnich@sandia.gov>,
samba-technical@lists.samba.org, Steve French <sfrench@samba.org>,
Trond Myklebust <trond.myklebust@primarydata.com>,
v9fs-developer@lists.sourceforge.net
Subject: Re: [PATCH v2 1/2] dax: prevent invalidation of mapped DAX entries
Date: Mon, 8 May 2017 11:08:36 -0600 [thread overview]
Message-ID: <20170508170836.GA19867@linux.intel.com> (raw)
In-Reply-To: <20170505072912.GA25424@quack2.suse.cz>
On Fri, May 05, 2017 at 09:29:12AM +0200, Jan Kara wrote:
> On Thu 04-05-17 13:59:09, Ross Zwisler wrote:
> > dax_invalidate_mapping_entry() currently removes DAX exceptional entries
> > only if they are clean and unlocked. This is done via:
> >
> > invalidate_mapping_pages()
> > invalidate_exceptional_entry()
> > dax_invalidate_mapping_entry()
> >
> > However, for page cache pages removed in invalidate_mapping_pages() there
> > is an additional criteria which is that the page must not be mapped. This
> > is noted in the comments above invalidate_mapping_pages() and is checked in
> > invalidate_inode_page().
> >
> > For DAX entries this means that we can can end up in a situation where a
> > DAX exceptional entry, either a huge zero page or a regular DAX entry,
> > could end up mapped but without an associated radix tree entry. This is
> > inconsistent with the rest of the DAX code and with what happens in the
> > page cache case.
> >
> > We aren't able to unmap the DAX exceptional entry because according to its
> > comments invalidate_mapping_pages() isn't allowed to block, and
> > unmap_mapping_range() takes a write lock on the mapping->i_mmap_rwsem.
> >
> > We could potentially do an rmap walk to see if each of the entries actually
> > has any active mappings before we remove it, but this might end up being
> > very expensive and doesn't currently look to be worth it.
> >
> > So, just remove dax_invalidate_mapping_entry() and leave the DAX entries in
> > the radix tree.
> >
> > Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
> > Fixes: c6dcf52c23d2 ("mm: Invalidate DAX radix tree entries only if appropriate")
> > Reported-by: Jan Kara <jack@suse.cz>
> > Reviewed-by: Jan Kara <jack@suse.cz>
> > Cc: <stable@vger.kernel.org> [4.10+]
>
> Ah, I've just sent out a series which contains these two patches and
> another two patches which change the entry locking to fix the last spotted
> race... So either just take my last two patches on top of these two or
> take my series as a whole.
Sounds good. You added a better comment in invalidate_inode_pages2_range(), so
let's just use your version of this series.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
WARNING: multiple messages have this Message-ID (diff)
From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Jan Kara <jack@suse.cz>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Alexander Viro <viro@zeniv.linux.org.uk>,
Alexey Kuznetsov <kuznet@virtuozzo.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Anna Schumaker <anna.schumaker@netapp.com>,
Christoph Hellwig <hch@lst.de>,
Dan Williams <dan.j.williams@intel.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
Eric Van Hensbergen <ericvh@gmail.com>,
Jens Axboe <axboe@kernel.dk>,
Johannes Weiner <hannes@cmpxchg.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Latchesar Ionkov <lucho@ionkov.net>,
linux-cifs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, linux-nfs@vger.kernel.org,
linux-nvdimm@lists.01.org,
Matthew Wilcox <mawilcox@microsoft.com>,
Ron Minnich <rminnich@sandia.gov>,
samba-technical@lists.samba.org, Steve French <sfrench@samba.org>,
Trond Myklebust <trond.myklebust@primarydata.com>,
v9fs-developer@lists.sourceforge.net
Subject: Re: [PATCH v2 1/2] dax: prevent invalidation of mapped DAX entries
Date: Mon, 8 May 2017 11:08:36 -0600 [thread overview]
Message-ID: <20170508170836.GA19867@linux.intel.com> (raw)
In-Reply-To: <20170505072912.GA25424@quack2.suse.cz>
On Fri, May 05, 2017 at 09:29:12AM +0200, Jan Kara wrote:
> On Thu 04-05-17 13:59:09, Ross Zwisler wrote:
> > dax_invalidate_mapping_entry() currently removes DAX exceptional entries
> > only if they are clean and unlocked. This is done via:
> >
> > invalidate_mapping_pages()
> > invalidate_exceptional_entry()
> > dax_invalidate_mapping_entry()
> >
> > However, for page cache pages removed in invalidate_mapping_pages() there
> > is an additional criteria which is that the page must not be mapped. This
> > is noted in the comments above invalidate_mapping_pages() and is checked in
> > invalidate_inode_page().
> >
> > For DAX entries this means that we can can end up in a situation where a
> > DAX exceptional entry, either a huge zero page or a regular DAX entry,
> > could end up mapped but without an associated radix tree entry. This is
> > inconsistent with the rest of the DAX code and with what happens in the
> > page cache case.
> >
> > We aren't able to unmap the DAX exceptional entry because according to its
> > comments invalidate_mapping_pages() isn't allowed to block, and
> > unmap_mapping_range() takes a write lock on the mapping->i_mmap_rwsem.
> >
> > We could potentially do an rmap walk to see if each of the entries actually
> > has any active mappings before we remove it, but this might end up being
> > very expensive and doesn't currently look to be worth it.
> >
> > So, just remove dax_invalidate_mapping_entry() and leave the DAX entries in
> > the radix tree.
> >
> > Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
> > Fixes: c6dcf52c23d2 ("mm: Invalidate DAX radix tree entries only if appropriate")
> > Reported-by: Jan Kara <jack@suse.cz>
> > Reviewed-by: Jan Kara <jack@suse.cz>
> > Cc: <stable@vger.kernel.org> [4.10+]
>
> Ah, I've just sent out a series which contains these two patches and
> another two patches which change the entry locking to fix the last spotted
> race... So either just take my last two patches on top of these two or
> take my series as a whole.
Sounds good. You added a better comment in invalidate_inode_pages2_range(), so
let's just use your version of this series.
next prev parent reply other threads:[~2017-05-08 17:08 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-04 19:59 [PATCH v2 1/2] dax: prevent invalidation of mapped DAX entries Ross Zwisler
2017-05-04 19:59 ` Ross Zwisler
2017-05-04 19:59 ` Ross Zwisler
2017-05-04 19:59 ` Ross Zwisler
2017-05-04 19:59 ` Ross Zwisler
2017-05-04 19:59 ` [PATCH v2 2/2] dax: fix data corruption due to stale mmap reads Ross Zwisler
2017-05-04 19:59 ` Ross Zwisler
2017-05-04 19:59 ` Ross Zwisler
2017-05-04 19:59 ` Ross Zwisler
2017-05-04 19:59 ` Ross Zwisler
2017-05-05 7:29 ` [PATCH v2 1/2] dax: prevent invalidation of mapped DAX entries Jan Kara
2017-05-05 7:29 ` Jan Kara
2017-05-05 7:29 ` Jan Kara
2017-05-05 7:29 ` Jan Kara
2017-05-05 7:29 ` Jan Kara
2017-05-08 17:08 ` Ross Zwisler [this message]
2017-05-08 17:08 ` Ross Zwisler
2017-05-08 17:08 ` Ross Zwisler
2017-05-08 17:08 ` Ross Zwisler
2017-05-08 17:08 ` Ross Zwisler
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170508170836.GA19867@linux.intel.com \
--to=ross.zwisler@linux.intel.com \
--cc=akpm@linux-foundation.org \
--cc=anna.schumaker@netapp.com \
--cc=aryabinin@virtuozzo.com \
--cc=axboe@kernel.dk \
--cc=darrick.wong@oracle.com \
--cc=ericvh@gmail.com \
--cc=hannes@cmpxchg.org \
--cc=hch@lst.de \
--cc=jack@suse.cz \
--cc=kuznet@virtuozzo.com \
--cc=linux-cifs@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-nfs@vger.kernel.org \
--cc=linux-nvdimm@lists.01.org \
--cc=lucho@ionkov.net \
--cc=mawilcox@microsoft.com \
--cc=rminnich@sandia.gov \
--cc=samba-technical@lists.samba.org \
--cc=sfrench@samba.org \
--cc=trond.myklebust@primarydata.com \
--cc=v9fs-developer@lists.sourceforge.net \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.