linux-kernel - Re: [PATCH][man-pages] sync.2: syncfs() now returns errors if writeback fails

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Message-ID: <36f0f92ef664b4b62d6b2d06961a548d4dc5527b.camel@kernel.org>
Date:   Thu, 25 Jun 2020 19:37:59 -0400
From:   Jeff Layton <jlayton@...nel.org>
To:     "Michael Kerrisk (man-pages)" <mtk.manpages@...il.com>,
        Eric Biggers <ebiggers@...nel.org>
Cc:     linux-man@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH][man-pages] sync.2: syncfs() now returns errors if
 writeback fails

On Thu, 2020-06-25 at 11:45 +0200, Michael Kerrisk (man-pages) wrote:
> Hi Jeff,
> 
> Any progress with v2 of this patch?
> 
> Thanks,
> 
> Michael
> 

Just sent it. Thanks for the reminder!

> 
> On 6/10/20 11:19 PM, Jeff Layton wrote:
> > On Wed, 2020-06-10 at 08:50 -0700, Eric Biggers wrote:
> > > On Wed, Jun 10, 2020 at 06:33:47AM -0400, Jeff Layton wrote:
> > > > A patch has been merged for v5.8 that changes how syncfs() reports
> > > > errors. Change the sync() manpage accordingly.
> > > > 
> > > > Signed-off-by: Jeff Layton <jlayton@...nel.org>
> > > > ---
> > > >  man2/sync.2 | 24 +++++++++++++++++++++++-
> > > >  1 file changed, 23 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/man2/sync.2 b/man2/sync.2
> > > > index 7198f3311b05..27e04cff5845 100644
> > > > --- a/man2/sync.2
> > > > +++ b/man2/sync.2
> > > > @@ -86,11 +86,26 @@ to indicate the error.
> > > >  is always successful.
> > > >  .PP
> > > >  .BR syncfs ()
> > > > -can fail for at least the following reason:
> > > > +can fail for at least the following reasons:
> > > >  .TP
> > > >  .B EBADF
> > > >  .I fd
> > > >  is not a valid file descriptor.
> > > > +.TP
> > > > +.B EIO
> > > > +An error occurred during synchronization.
> > > > +This error may relate to data written to any file on the filesystem, or on
> > > > +metadata related to the filesytem itself.
> > > > +.TP
> > > > +.B ENOSPC
> > > > +Disk space was exhausted while synchronizing.
> > > > +.TP
> > > > +.BR ENOSPC ", " EDQUOT
> > > > +Data was written to a files on NFS or another filesystem which does not
> > > > +allocate space at the time of a
> > > > +.BR write (2)
> > > > +system call, and some previous write failed due to insufficient
> > > > +storage space.
> > > >  .SH VERSIONS
> > > >  .BR syncfs ()
> > > >  first appeared in Linux 2.6.39;
> > > > @@ -121,6 +136,13 @@ or
> > > >  .BR syncfs ()
> > > >  provide the same guarantees as fsync called on every file in
> > > >  the system or filesystem respectively.
> > > > +.PP
> > > > +In mainline kernel versions prior to 5.8,
> > > > +.\" commit 735e4ae5ba28c886d249ad04d3c8cc097dad6336
> > > > +.BR syncfs ()
> > > > +will only fail with EBADF when passed a bad file descriptor. In 5.8
> > > > +and later kernels, it will also report an error if one or more inodes failed
> > > > +to be written back since the last syncfs call.
> > > 
> > > The sentence "In mainline kernel versions prior to 5.8, syncfs() will only fail
> > > with EBADF when passed a bad file descriptor" is ambiguous.  It could mean that
> > > EBADF can now mean other things too.
> > > 
> > > Maybe write: "In mainline kernel versions prior to 5.8, syncfs() will only fail
> > > when passed a bad file descriptor (EBADF)."
> > > 
> > > - Eric
> > 
> > Good point. Fixed in my tree using your verbiage. I'll send out a v2
> > patch once I give others a chance to comment.
> > 
> > Thanks!
> > 
> 
> 

-- 
Jeff Layton <jlayton@...nel.org>