From: Jan Kara <jack@suse.cz>
To: ira.weiny@intel.com
Cc: "Theodore Ts'o" <tytso@mit.edu>,
linux-nvdimm@lists.01.org, "Dave Chinner" <david@fromorbit.com>,
"Jeff Layton" <jlayton@kernel.org>,
linux-kernel@vger.kernel.org,
"Matthew Wilcox" <willy@infradead.org>,
linux-xfs@vger.kernel.org, linux-mm@kvack.org,
"Jérôme Glisse" <jglisse@redhat.com>,
"John Hubbard" <jhubbard@nvidia.com>,
linux-fsdevel@vger.kernel.org, "Jan Kara" <jack@suse.cz>,
linux-ext4@vger.kernel.org,
"Andrew Morton" <akpm@linux-foundation.org>
Subject: Re: [PATCH RFC 07/10] fs/ext4: Fail truncate if pages are GUP pinned
Date: Thu, 6 Jun 2019 12:58:55 +0200 [thread overview]
Message-ID: <20190606105855.GG7433@quack2.suse.cz> (raw)
In-Reply-To: <20190606014544.8339-8-ira.weiny@intel.com>
On Wed 05-06-19 18:45:40, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
>
> If pages are actively gup pinned fail the truncate operation.
>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> ---
> fs/ext4/inode.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 75f543f384e4..1ded83ec08c0 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -4250,6 +4250,9 @@ int ext4_break_layouts(struct inode *inode, loff_t offset, loff_t len)
> if (!page)
> return 0;
>
> + if (page_gup_pinned(page))
> + return -ETXTBSY;
> +
> error = ___wait_var_event(&page->_refcount,
> atomic_read(&page->_refcount) == 1,
> TASK_INTERRUPTIBLE, 0, 0,
This caught my eye. Does this mean that now truncate for a file which has
temporary gup users (such buffers for DIO) can fail with ETXTBUSY? That
doesn't look desirable. If we would mandate layout lease while pages are
pinned as I suggested, this could be dealt with by checking for leases with
pins (breaking such lease would return error and not break it) and if
breaking leases succeeds (i.e., there are no long-term pinned pages), we'd
just wait for the remaining references as we do now.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
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WARNING: multiple messages have this Message-ID (diff)
From: Jan Kara <jack@suse.cz>
To: ira.weiny@intel.com
Cc: "Dan Williams" <dan.j.williams@intel.com>,
"Jan Kara" <jack@suse.cz>, "Theodore Ts'o" <tytso@mit.edu>,
"Jeff Layton" <jlayton@kernel.org>,
"Dave Chinner" <david@fromorbit.com>,
"Matthew Wilcox" <willy@infradead.org>,
linux-xfs@vger.kernel.org,
"Andrew Morton" <akpm@linux-foundation.org>,
"John Hubbard" <jhubbard@nvidia.com>,
"Jérôme Glisse" <jglisse@redhat.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-nvdimm@lists.01.org, linux-ext4@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH RFC 07/10] fs/ext4: Fail truncate if pages are GUP pinned
Date: Thu, 6 Jun 2019 12:58:55 +0200 [thread overview]
Message-ID: <20190606105855.GG7433@quack2.suse.cz> (raw)
In-Reply-To: <20190606014544.8339-8-ira.weiny@intel.com>
On Wed 05-06-19 18:45:40, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
>
> If pages are actively gup pinned fail the truncate operation.
>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> ---
> fs/ext4/inode.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 75f543f384e4..1ded83ec08c0 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -4250,6 +4250,9 @@ int ext4_break_layouts(struct inode *inode, loff_t offset, loff_t len)
> if (!page)
> return 0;
>
> + if (page_gup_pinned(page))
> + return -ETXTBSY;
> +
> error = ___wait_var_event(&page->_refcount,
> atomic_read(&page->_refcount) == 1,
> TASK_INTERRUPTIBLE, 0, 0,
This caught my eye. Does this mean that now truncate for a file which has
temporary gup users (such buffers for DIO) can fail with ETXTBUSY? That
doesn't look desirable. If we would mandate layout lease while pages are
pinned as I suggested, this could be dealt with by checking for leases with
pins (breaking such lease would return error and not break it) and if
breaking leases succeeds (i.e., there are no long-term pinned pages), we'd
just wait for the remaining references as we do now.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2019-06-06 10:58 UTC|newest]
Thread overview: 136+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-06 1:45 [PATCH RFC 00/10] RDMA/FS DAX truncate proposal ira.weiny
2019-06-06 1:45 ` ira.weiny
2019-06-06 1:45 ` [PATCH RFC 01/10] fs/locks: Add trace_leases_conflict ira.weiny
2019-06-09 12:52 ` Jeff Layton
2019-06-06 1:45 ` [PATCH RFC 02/10] fs/locks: Export F_LAYOUT lease to user space ira.weiny
2019-06-06 1:45 ` ira.weiny
2019-06-09 13:00 ` Jeff Layton
2019-06-09 13:00 ` Jeff Layton
2019-06-11 21:38 ` Ira Weiny
2019-06-11 21:38 ` Ira Weiny
2019-06-12 9:46 ` Jan Kara
2019-06-06 1:45 ` [PATCH RFC 03/10] mm/gup: Pass flags down to __gup_device_huge* calls ira.weiny
2019-06-06 1:45 ` ira.weiny
2019-06-06 6:18 ` Christoph Hellwig
2019-06-06 16:10 ` Ira Weiny
2019-06-06 1:45 ` [PATCH RFC 04/10] mm/gup: Ensure F_LAYOUT lease is held prior to GUP'ing pages ira.weiny
2019-06-06 1:45 ` ira.weiny
2019-06-06 1:45 ` [PATCH RFC 05/10] fs/ext4: Teach ext4 to break layout leases ira.weiny
2019-06-06 1:45 ` ira.weiny
2019-06-06 1:45 ` [PATCH RFC 06/10] fs/ext4: Teach dax_layout_busy_page() to operate on a sub-range ira.weiny
2019-06-06 1:45 ` ira.weiny
2019-06-06 1:45 ` [PATCH RFC 07/10] fs/ext4: Fail truncate if pages are GUP pinned ira.weiny
2019-06-06 1:45 ` ira.weiny
2019-06-06 10:58 ` Jan Kara [this message]
2019-06-06 10:58 ` Jan Kara
2019-06-06 16:17 ` Ira Weiny
2019-06-06 1:45 ` [PATCH RFC 08/10] fs/xfs: Teach xfs to use new dax_layout_busy_page() ira.weiny
2019-06-06 1:45 ` ira.weiny
2019-06-06 1:45 ` [PATCH RFC 09/10] fs/xfs: Fail truncate if pages are GUP pinned ira.weiny
2019-06-06 1:45 ` ira.weiny
2019-06-06 1:45 ` [PATCH RFC 10/10] mm/gup: Remove FOLL_LONGTERM DAX exclusion ira.weiny
2019-06-06 1:45 ` ira.weiny
2019-06-06 5:52 ` [PATCH RFC 00/10] RDMA/FS DAX truncate proposal John Hubbard
2019-06-06 5:52 ` John Hubbard
2019-06-06 17:11 ` Ira Weiny
2019-06-06 17:11 ` Ira Weiny
2019-06-06 19:46 ` Jason Gunthorpe
2019-06-06 10:42 ` Jan Kara
2019-06-06 15:35 ` Dan Williams
2019-06-06 19:51 ` Jason Gunthorpe
2019-06-06 22:22 ` Ira Weiny
2019-06-07 10:36 ` Jan Kara
2019-06-07 12:17 ` Jason Gunthorpe
2019-06-07 14:52 ` Ira Weiny
2019-06-07 14:52 ` Ira Weiny
2019-06-07 15:10 ` Jason Gunthorpe
2019-06-12 10:29 ` Jan Kara
2019-06-12 10:29 ` Jan Kara
2019-06-12 11:47 ` Jason Gunthorpe
2019-06-12 12:09 ` Jan Kara
2019-06-12 12:09 ` Jan Kara
2019-06-12 18:41 ` Dan Williams
2019-06-13 7:17 ` Jan Kara
2019-06-13 7:17 ` Jan Kara
2019-06-12 19:14 ` Jason Gunthorpe
2019-06-12 22:13 ` Ira Weiny
2019-06-12 22:54 ` Dan Williams
2019-06-12 22:54 ` Dan Williams
2019-06-12 23:33 ` Ira Weiny
2019-06-12 23:33 ` Ira Weiny
2019-06-13 1:14 ` Dan Williams
2019-06-13 1:14 ` Dan Williams
2019-06-13 15:13 ` Jason Gunthorpe
2019-06-13 16:25 ` Dan Williams
2019-06-13 16:25 ` Dan Williams
2019-06-13 17:18 ` Jason Gunthorpe
2019-06-13 16:53 ` Dan Williams
2019-06-13 16:53 ` Dan Williams
2019-06-13 15:12 ` Jason Gunthorpe
2019-06-13 7:53 ` Jan Kara
2019-06-13 7:53 ` Jan Kara
2019-06-12 18:49 ` Dan Williams
2019-06-12 18:49 ` Dan Williams
2019-06-13 7:43 ` Jan Kara
2019-06-06 22:03 ` Ira Weiny
2019-06-06 22:03 ` Ira Weiny
2019-06-06 22:26 ` Ira Weiny
2019-06-06 22:28 ` Dave Chinner
2019-06-07 11:04 ` Jan Kara
2019-06-07 18:25 ` Ira Weiny
2019-06-07 18:25 ` Ira Weiny
2019-06-07 18:25 ` Ira Weiny
2019-06-07 18:50 ` Jason Gunthorpe
2019-06-08 0:10 ` Dave Chinner
2019-06-08 0:10 ` Dave Chinner
2019-06-09 1:29 ` Ira Weiny
2019-06-09 1:29 ` Ira Weiny
2019-06-09 1:29 ` Ira Weiny
2019-06-12 12:37 ` Matthew Wilcox
2019-06-12 12:37 ` Matthew Wilcox
2019-06-12 12:37 ` Matthew Wilcox
2019-06-12 23:30 ` Ira Weiny
2019-06-12 23:30 ` Ira Weiny
2019-06-12 23:30 ` Ira Weiny
2019-06-13 0:55 ` Dave Chinner
2019-06-13 0:55 ` Dave Chinner
2019-06-13 0:55 ` Dave Chinner
2019-06-13 20:34 ` Ira Weiny
2019-06-13 20:34 ` Ira Weiny
2019-06-13 20:34 ` Ira Weiny
2019-06-14 3:42 ` Dave Chinner
2019-06-13 0:25 ` Dave Chinner
2019-06-13 0:25 ` Dave Chinner
2019-06-13 3:23 ` Matthew Wilcox
2019-06-13 3:23 ` Matthew Wilcox
2019-06-13 3:23 ` Matthew Wilcox
2019-06-13 4:36 ` Dave Chinner
2019-06-13 4:36 ` Dave Chinner
2019-06-13 4:36 ` Dave Chinner
2019-06-13 10:47 ` Matthew Wilcox
2019-06-13 10:47 ` Matthew Wilcox
2019-06-13 10:47 ` Matthew Wilcox
2019-06-13 15:29 ` Jason Gunthorpe
2019-06-13 15:27 ` Matthew Wilcox
2019-06-13 15:27 ` Matthew Wilcox
2019-06-13 15:27 ` Matthew Wilcox
2019-06-13 21:13 ` Ira Weiny
2019-06-13 21:13 ` Ira Weiny
2019-06-13 23:45 ` Jason Gunthorpe
2019-06-14 0:00 ` Ira Weiny
2019-06-14 0:00 ` Ira Weiny
2019-06-14 2:09 ` Dave Chinner
2019-06-14 2:09 ` Dave Chinner
2019-06-14 2:09 ` Dave Chinner
2019-06-14 2:31 ` Matthew Wilcox
2019-06-14 2:31 ` Matthew Wilcox
2019-06-14 3:07 ` Dave Chinner
2019-06-14 3:07 ` Dave Chinner
2019-06-14 3:07 ` Dave Chinner
2019-06-20 14:52 ` Jan Kara
2019-06-20 14:52 ` Jan Kara
2019-06-13 20:34 ` Ira Weiny
2019-06-13 20:34 ` Ira Weiny
2019-06-13 20:34 ` Ira Weiny
2019-06-14 2:58 ` Dave Chinner
2019-06-14 2:58 ` Dave Chinner
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