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From: Matthew Wilcox <mawilcox@microsoft.com>
To: Jeff Layton <jlayton@poochiereds.net>,
	"Darrick J. Wong" <darrick.wong@oracle.com>,
	"jlayton@kernel.org" <jlayton@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Al Viro <viro@ZenIV.linux.org.uk>, Jan Kara <jack@suse.cz>,
	"tytso@mit.edu" <tytso@mit.edu>,
	"axboe@kernel.dk" <axboe@kernel.dk>,
	"ross.zwisler@linux.intel.com" <ross.zwisler@linux.intel.com>,
	"corbet@lwn.net" <corbet@lwn.net>, Chris Mason <clm@fb.com>,
	Josef Bacik <jbacik@fb.com>, David Sterba <dsterba@suse.com>,
	Carlos Maiolino <cmaiolino@redhat.com>,
	Eryu Guan <eguan@redhat.com>, David Howells <dhowells@redhat.com>,
	Christoph Hellwig <hch@infradead.org>,
	Liu Bo <bo.li.liu@oracle.com>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>,
	"linux-xfs@vger.kernel.org" <linux-xfs@vger.kernel.org>,
	"linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>
Subject: RE: [PATCH v8 12/18] Documentation: flesh out the section in vfs.txt on storing and reporting writeback errors
Date: Thu, 29 Jun 2017 18:21:50 +0000	[thread overview]
Message-ID: <BY2PR21MB003653755FD85FCE2C49393ECBD20@BY2PR21MB0036.namprd21.prod.outlook.com> (raw)
In-Reply-To: <1498760014.22569.13.camel@poochiereds.net>

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WARNING: multiple messages have this Message-ID
From: Matthew Wilcox <mawilcox@microsoft.com>
To: Jeff Layton <jlayton@poochiereds.net>,
	"Darrick J. Wong" <darrick.wong@oracle.com>,
	"jlayton@kernel.org" <jlayton@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Al Viro <viro@ZenIV.linux.org.uk>, Jan Kara <jack@suse.cz>,
	"tytso@mit.edu" <tytso@mit.edu>,
	"axboe@kernel.dk" <axboe@kernel.dk>,
	"ross.zwisler@linux.intel.com" <ross.zwisler@linux.intel.com>,
	"corbet@lwn.net" <corbet@lwn.net>, Chris Mason <clm@fb.com>,
	Josef Bacik <jbacik@fb.com>, David Sterba <dsterba@suse.com>,
	Carlos Maiolino <cmaiolino@redhat.com>,
	Eryu Guan <eguan@redhat.com>, David Howells <dhowells@redhat.com>,
	Christoph Hellwig <hch@infradead.org>,
	Liu Bo <bo.li.liu@oracle.com>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>,
	"linux-xfs@vger.kernel.org" <linux-xfs@vger.kernel.org>,
	"linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>
Subject: RE: [PATCH v8 12/18] Documentation: flesh out the section in vfs.txt on storing and reporting writeback errors
Date: Thu, 29 Jun 2017 18:21:50 +0000	[thread overview]
Message-ID: <BY2PR21MB003653755FD85FCE2C49393ECBD20@BY2PR21MB0036.namprd21.prod.outlook.com> (raw)
In-Reply-To: <1498760014.22569.13.camel@poochiereds.net>

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="utf-8", Size: 1610 bytes --]

From: Jeff Layton [mailto:jlayton@poochiereds.net]
> On Thu, 2017-06-29 at 10:11 -0700, Darrick J. Wong wrote:
> > On Thu, Jun 29, 2017 at 09:19:48AM -0400, jlayton@kernel.org wrote:
> > > +Handling errors during writeback
> > > +--------------------------------
> > > +Most applications that utilize the pagecache will periodically call
> > > +fsync to ensure that data written has made it to the backing store.
> >
> > /me wonders if this sentence ought to be worded more strongly, e.g.
> >
> > "Applications that utilize the pagecache must call a data
> > synchronization syscall such as fsync, fdatasync, or msync to ensure
> > that data written has made it to the backing store."
> 
> Well...only if they care about the data. There are some that don't. :)

Also, applications don't "utilize the pagecache"; filesystems use the pagecache.
Applications may or may not use cached I/O.  How about this:

Applications which care about data integrity and use cached I/O will
periodically call fsync(), msync() or fdatasync() to ensure that their
data is durable.

> What should we do about sync_file_range here? It doesn't currently call
> any filesystem operations directly, so we don't have a good way to make
> it selectively use errseq_t handling there.
> 
> I could resurrect the FS_* flag for that, though I don't really like
> that. Should I just go ahead and convert it over to use errseq_t under
> the theory that most callers will eventually want that anyway?

I think so.

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WARNING: multiple messages have this Message-ID
From: Matthew Wilcox <mawilcox@microsoft.com>
To: Jeff Layton <jlayton@poochiereds.net>,
	"Darrick J. Wong" <darrick.wong@oracle.com>,
	"jlayton@kernel.org" <jlayton@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Al Viro <viro@ZenIV.linux.org.uk>, Jan Kara <jack@suse.cz>,
	"tytso@mit.edu" <tytso@mit.edu>,
	"axboe@kernel.dk" <axboe@kernel.dk>,
	"ross.zwisler@linux.intel.com" <ross.zwisler@linux.intel.com>,
	"corbet@lwn.net" <corbet@lwn.net>, Chris Mason <clm@fb.com>,
	Josef Bacik <jbacik@fb.com>, David Sterba <dsterba@suse.com>,
	Carlos Maiolino <cmaiolino@redhat.com>,
	Eryu Guan <eguan@redhat.com>, David Howells <dhowells@redhat.com>,
	Christoph Hellwig <hch@infradead.org>,
	Liu Bo <bo.li.liu@oracle.com>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>,
	"linux-xfs@vger.kernel.org" <linux-xfs@vger.kernel.org>,
	"linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>
Subject: RE: [PATCH v8 12/18] Documentation: flesh out the section in vfs.txt on storing and reporting writeback errors
Date: Thu, 29 Jun 2017 18:21:50 +0000	[thread overview]
Message-ID: <BY2PR21MB003653755FD85FCE2C49393ECBD20@BY2PR21MB0036.namprd21.prod.outlook.com> (raw)
In-Reply-To: <1498760014.22569.13.camel@poochiereds.net>

From: Jeff Layton [mailto:jlayton@poochiereds.net]
> On Thu, 2017-06-29 at 10:11 -0700, Darrick J. Wong wrote:
> > On Thu, Jun 29, 2017 at 09:19:48AM -0400, jlayton@kernel.org wrote:
> > > +Handling errors during writeback
> > > +--------------------------------
> > > +Most applications that utilize the pagecache will periodically call
> > > +fsync to ensure that data written has made it to the backing store.
> >
> > /me wonders if this sentence ought to be worded more strongly, e.g.
> >
> > "Applications that utilize the pagecache must call a data
> > synchronization syscall such as fsync, fdatasync, or msync to ensure
> > that data written has made it to the backing store."
> 
> Well...only if they care about the data. There are some that don't. :)

Also, applications don't "utilize the pagecache"; filesystems use the pagecache.
Applications may or may not use cached I/O.  How about this:

Applications which care about data integrity and use cached I/O will
periodically call fsync(), msync() or fdatasync() to ensure that their
data is durable.

> What should we do about sync_file_range here? It doesn't currently call
> any filesystem operations directly, so we don't have a good way to make
> it selectively use errseq_t handling there.
> 
> I could resurrect the FS_* flag for that, though I don't really like
> that. Should I just go ahead and convert it over to use errseq_t under
> the theory that most callers will eventually want that anyway?

I think so.


  reply	other threads:[~2017-06-29 18:21 UTC|newest]

Thread overview: 90+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-29 13:19 [PATCH v8 00/18] fs: enhanced writeback error reporting with errseq_t (pile #1) jlayton
2017-06-29 13:19 ` jlayton
2017-06-29 13:19 ` [PATCH v8 01/18] fs: remove call_fsync helper function jlayton
2017-06-29 13:19   ` jlayton
2017-06-29 13:19 ` [PATCH v8 02/18] buffer: use mapping_set_error instead of setting the flag jlayton
2017-06-29 13:19   ` jlayton
2017-06-29 13:19 ` [PATCH v8 03/18] fs: check for writeback errors after syncing out buffers in generic_file_fsync jlayton
2017-06-29 13:19   ` jlayton
2017-06-29 14:19   ` Christoph Hellwig
2017-06-29 14:19     ` Christoph Hellwig
2017-06-29 20:17     ` Jeff Layton
2017-06-29 20:17       ` Jeff Layton
2017-06-29 20:17       ` Jeff Layton
2017-06-29 20:17       ` Jeff Layton
2017-06-29 13:19 ` [PATCH v8 04/18] buffer: set errors in mapping at the time that the error occurs jlayton
2017-06-29 13:19   ` jlayton
2017-06-29 13:19 ` [PATCH v8 05/18] jbd2: don't clear and reset errors after waiting on writeback jlayton
2017-06-29 13:19   ` jlayton
2017-06-29 13:19 ` [PATCH v8 06/18] mm: clear AS_EIO/AS_ENOSPC when writeback initiation fails jlayton
2017-06-29 13:19   ` jlayton
2017-06-29 13:19 ` [PATCH v8 07/18] mm: don't TestClearPageError in __filemap_fdatawait_range jlayton
2017-06-29 13:19   ` jlayton
2017-06-29 13:19 ` [PATCH v8 08/18] mm: clean up error handling in write_one_page jlayton
2017-06-29 13:19   ` jlayton
2017-06-29 13:19 ` [PATCH v8 09/18] lib: add errseq_t type and infrastructure for handling it jlayton
2017-06-29 13:19   ` jlayton
2017-06-29 13:19 ` [PATCH v8 10/18] fs: new infrastructure for writeback error handling and reporting jlayton
2017-06-29 13:19   ` jlayton
2017-06-29 13:45   ` Jeff Layton
2017-06-29 13:45     ` Jeff Layton
2017-06-29 13:45     ` Jeff Layton
2017-06-29 13:45     ` Jeff Layton
2017-06-29 17:52   ` Jeff Layton
2017-06-29 17:52     ` Jeff Layton
2017-06-29 17:52     ` Jeff Layton
2017-06-29 17:52     ` Jeff Layton
2017-06-29 13:19 ` [PATCH v8 11/18] mm: set both AS_EIO/AS_ENOSPC and errseq_t in mapping_set_error jlayton
2017-06-29 13:19   ` jlayton
2017-06-29 13:19 ` [PATCH v8 12/18] Documentation: flesh out the section in vfs.txt on storing and reporting writeback errors jlayton
2017-06-29 13:19   ` jlayton
2017-06-29 17:11   ` Darrick J. Wong
2017-06-29 17:11     ` Darrick J. Wong
2017-06-29 18:13     ` Jeff Layton
2017-06-29 18:13       ` Jeff Layton
2017-06-29 18:13       ` Jeff Layton
2017-06-29 18:13       ` Jeff Layton
2017-06-29 18:21       ` Matthew Wilcox [this message]
2017-06-29 18:21         ` Matthew Wilcox
2017-06-29 18:21         ` Matthew Wilcox
2017-06-29 20:42         ` Jeff Layton
2017-06-29 20:42           ` Jeff Layton
2017-06-29 20:42           ` Jeff Layton
2017-06-29 20:42           ` Jeff Layton
2017-06-29 20:42           ` Jeff Layton
2017-06-29 13:19 ` [PATCH v8 13/18] dax: set errors in mapping when writeback fails jlayton
2017-06-29 13:19   ` jlayton
2017-06-29 13:19 ` [PATCH v8 14/18] block: convert to errseq_t based writeback error tracking jlayton
2017-06-29 13:19   ` jlayton
2017-06-29 14:18   ` Christoph Hellwig
2017-06-29 14:18     ` Christoph Hellwig
2017-06-29 13:19 ` [PATCH v8 15/18] fs: convert __generic_file_fsync to use errseq_t based reporting jlayton
2017-06-29 13:19   ` jlayton
2017-06-29 13:19 ` [PATCH v8 16/18] ext4: use errseq_t based error handling for reporting data writeback errors jlayton
2017-06-29 13:19   ` jlayton
2017-06-29 14:12   ` Christoph Hellwig
2017-06-29 14:12     ` Christoph Hellwig
2017-06-29 20:26     ` Jeff Layton
2017-06-29 20:26       ` Jeff Layton
2017-06-29 20:26       ` Jeff Layton
2017-06-29 20:26       ` Jeff Layton
2017-06-29 13:19 ` [PATCH v8 17/18] xfs: minimal conversion to errseq_t writeback error reporting jlayton
2017-06-29 13:19   ` jlayton
2017-06-29 14:12   ` Christoph Hellwig
2017-06-29 14:12     ` Christoph Hellwig
2017-06-30 16:45     ` Jeff Layton
2017-06-30 16:45       ` Jeff Layton
2017-06-30 16:45       ` Jeff Layton
2017-06-30 16:45       ` Jeff Layton
2017-06-30 16:49       ` Christoph Hellwig
2017-06-30 16:49         ` Christoph Hellwig
2017-06-29 17:13   ` Darrick J. Wong
2017-06-29 17:13     ` Darrick J. Wong
2017-06-29 13:19 ` [PATCH v8 18/18] btrfs: minimal conversion to errseq_t writeback error reporting on fsync jlayton
2017-06-29 13:19   ` jlayton
2017-06-29 14:17   ` Christoph Hellwig
2017-06-29 14:17     ` Christoph Hellwig
2017-06-29 20:32     ` Jeff Layton
2017-06-29 20:32       ` Jeff Layton
2017-06-29 20:32       ` Jeff Layton
2017-06-29 20:32       ` Jeff Layton

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