Re: [PATCH v2 05/15] xfs: mount-api - make xfs_parse_param() take context .parse_param() args

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Tue, Aug 27, 2019 at 08:41:20AM -0400, Brian Foster wrote:
> On Fri, Aug 23, 2019 at 08:59:43AM +0800, Ian Kent wrote:
> > Make xfs_parse_param() take arguments of the fs context operation
> > .parse_param() in preperation for switching to use the file system
> > mount context for mount.
> > 
> > The function fc_parse() only uses the file system context (fc here)
> > when calling log macros warnf() and invalf() which in turn check
> > only the fc->log field to determine if the message should be saved
> > to a context buffer (for later retrival by userspace) or logged
> > using printk().
> > 
> > Also the temporary function match_kstrtoint() is now unused, remove it.
> > 
> > Signed-off-by: Ian Kent <raven@themaw.net>
> > ---
> 
> I see Eric had some feedback on this patch already. Some additional
> notes (which may overlap)...
> 
> >  fs/xfs/xfs_super.c |  187 ++++++++++++++++++++++++++++++----------------------
> >  1 file changed, 108 insertions(+), 79 deletions(-)
> > 
> > diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> > index 3ae29938dd89..754d2ccfd960 100644
> > --- a/fs/xfs/xfs_super.c
> > +++ b/fs/xfs/xfs_super.c
> ...
> > @@ -275,33 +271,38 @@ xfs_parse_param(
> >  		mp->m_flags |= XFS_MOUNT_NOUUID;
> >  		break;
> >  	case Opt_ikeep:
> > -		mp->m_flags |= XFS_MOUNT_IKEEP;
> > -		break;
> > -	case Opt_noikeep:
> > -		mp->m_flags &= ~XFS_MOUNT_IKEEP;
> > +		if (result.negated)
> > +			mp->m_flags &= ~XFS_MOUNT_IKEEP;
> > +		else
> > +			mp->m_flags |= XFS_MOUNT_IKEEP;
> >  		break;
> >  	case Opt_largeio:
> > -		mp->m_flags &= ~XFS_MOUNT_COMPAT_IOSIZE;
> > -		break;
> > -	case Opt_nolargeio:
> > -		mp->m_flags |= XFS_MOUNT_COMPAT_IOSIZE;
> > +		if (result.negated)
> > +			mp->m_flags |= XFS_MOUNT_COMPAT_IOSIZE;
> > +		else
> > +			mp->m_flags &= ~XFS_MOUNT_COMPAT_IOSIZE;
> >  		break;
> >  	case Opt_attr2:
> > -		mp->m_flags |= XFS_MOUNT_ATTR2;
> > -		break;
> > -	case Opt_noattr2:
> > -		mp->m_flags &= ~XFS_MOUNT_ATTR2;
> > -		mp->m_flags |= XFS_MOUNT_NOATTR2;
> > +		if (!result.negated) {
> > +			mp->m_flags |= XFS_MOUNT_ATTR2;
> > +		} else {
> > +			mp->m_flags &= ~XFS_MOUNT_ATTR2;
> > +			mp->m_flags |= XFS_MOUNT_NOATTR2;
> > +		}
> 
> Eric's comments aside, it would be nice to have some consistency between
> the various result.negated checks (i.e. 'if (negated)' vs 'if
> (!negated)').

Frankly I'd prefer "if (result.enabled)" or something affirmative so I
don't have to twist my brain around !negated == MAIN SCREEN TURN ON.

--D

> >  		break;
> >  	case Opt_filestreams:
> >  		mp->m_flags |= XFS_MOUNT_FILESTREAMS;
> >  		break;
> > -	case Opt_noquota:
> > -		mp->m_qflags &= ~XFS_ALL_QUOTA_ACCT;
> > -		mp->m_qflags &= ~XFS_ALL_QUOTA_ENFD;
> > -		mp->m_qflags &= ~XFS_ALL_QUOTA_ACTIVE;
> > -		break;
> >  	case Opt_quota:
> > +		if (!result.negated) {
> > +			mp->m_qflags |= (XFS_UQUOTA_ACCT | XFS_UQUOTA_ACTIVE |
> > +					 XFS_UQUOTA_ENFD);
> > +		} else {
> > +			mp->m_qflags &= ~XFS_ALL_QUOTA_ACCT;
> > +			mp->m_qflags &= ~XFS_ALL_QUOTA_ENFD;
> > +			mp->m_qflags &= ~XFS_ALL_QUOTA_ACTIVE;
> > +		}
> > +		break;
> >  	case Opt_uquota:
> >  	case Opt_usrquota:
> >  		mp->m_qflags |= (XFS_UQUOTA_ACCT | XFS_UQUOTA_ACTIVE |
> ...
> > @@ -367,10 +368,10 @@ xfs_parseargs(
> >  {
> >  	const struct super_block *sb = mp->m_super;
> >  	char			*p;
> > -	substring_t		args[MAX_OPT_ARGS];
> > -	int			dsunit = 0;
> > -	int			dswidth = 0;
> > -	uint8_t			iosizelog = 0;
> > +
> > +	struct fs_context	fc;
> > +	struct xfs_fs_context	context;
> > +	struct xfs_fs_context	*ctx = &context;
> 
> I don't really see the point for having a separate pointer variable
> based on the code so far. Why not just do:
> 
> 	struct xfs_fs_context	ctx = {0,};
> 
> ... and pass by reference where necessary?
> 
> >  
> >  	/*
> >  	 * set up the mount name first so all the errors will refer to the
> > @@ -406,17 +407,41 @@ xfs_parseargs(
> >  	if (!options)
> >  		goto done;
> >  
> > +	memset(&fc, 0, sizeof(fc));
> > +	memset(&ctx, 0, sizeof(ctx));
> > +	fc.fs_private = ctx;
> > +	fc.s_fs_info = mp;
> > +
> >  	while ((p = strsep(&options, ",")) != NULL) {
> > -		int		token;
> > -		int		ret;
> > +		struct fs_parameter	param;
> > +		char			*value;
> > +		int			ret;
> >  
> >  		if (!*p)
> >  			continue;
> >  
> > -		token = match_token(p, tokens, args);
> > -		ret = xfs_parse_param(token, p, args, mp,
> > -				      &dsunit, &dswidth, &iosizelog);
> > -		if (ret)
> > +		param.key = p;
> > +		param.type = fs_value_is_string;
> > +		param.size = 0;
> > +
> > +		value = strchr(p, '=');
> > +		if (value) {
> > +			if (value == p)
> > +				continue;
> 
> What's the purpose of the above check? Why do we skip the param as
> opposed to return an error or something?
> 
> > +			*value++ = 0;
> > +			param.size = strlen(value);
> > +			if (param.size > 0) {
> > +				param.string = kmemdup_nul(value,
> > +							   param.size,
> > +							   GFP_KERNEL);
> > +				if (!param.string)
> > +					return -ENOMEM;
> > +			}
> > +		}
> > +
> > +		ret = xfs_parse_param(&fc, &param);
> > +		kfree(param.string);
> > +		if (ret < 0)
> >  			return ret;
> >  	}
> >  
> ...
> > @@ -1914,6 +1939,10 @@ static const struct super_operations xfs_super_operations = {
> >  	.free_cached_objects	= xfs_fs_free_cached_objects,
> >  };
> >  
> > +static const struct fs_context_operations xfs_context_ops = {
> > +	.parse_param = xfs_parse_param,
> > +};
> > +
> 
> It's probably better to introduce this in the first patch where it's used.
> 
> Brian
> 
> >  static struct file_system_type xfs_fs_type = {
> >  	.owner			= THIS_MODULE,
> >  	.name			= "xfs",
> >