Re: [PATCH v3 06/16] xfs: mount-api - make xfs_parse_param() take context .parse_param() args

[Brian Foster <bfoster@redhat.com>]

On Fri, Sep 20, 2019 at 05:56:04PM +0800, Ian Kent wrote:
> Make xfs_parse_param() take arguments of the fs context operation
> .parse_param() in preparation 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>
> ---

This fails to compile:

$ make -j 8 M=fs/xfs
  CC [M]  fs/xfs/xfs_super.o
fs/xfs/xfs_super.c: In function ‘xfs_parseargs’:
fs/xfs/xfs_super.c:461:7: error: ‘ctx’ undeclared (first use in this function)
      (ctx->dsunit || ctx->dswidth)) {
       ^~~
fs/xfs/xfs_super.c:461:7: note: each undeclared identifier is reported only once for each function it appears in
make[1]: *** [scripts/Makefile.build:280: fs/xfs/xfs_super.o] Error 1
make: *** [Makefile:1624: _module_fs/xfs] Error 2

>  fs/xfs/xfs_super.c |  135 ++++++++++++++++++++++++++++++----------------------
>  1 file changed, 79 insertions(+), 56 deletions(-)
> 
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index b04aebab69ab..041ab8b52a7d 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -191,57 +191,60 @@ suffix_kstrtoint(const char *s, unsigned int base, int *res)
>  	return ret;
>  }
>  
...
>  STATIC int
>  xfs_parse_param(
...
>  
> -	switch (token) {
> +	opt = fs_parse(fc, &xfs_fs_parameters, param, &result);
> +	if (opt < 0) {
> +		/*
> +		 * If fs_parse() returns -ENOPARAM and the parameter
> +		 * is "source" the VFS needs to handle this option
> +		 * in order to boot otherwise use the default case
> +		 * below to handle invalid options.
> +		 */
> +		if (opt != -ENOPARAM ||
> +		    strcmp(param->key, "source") == 0)
> +			return opt;

Why is this not something that is handled in core mount-api code? Every
filesystem needs this logic in order to be a rootfs..?

Brian

> +	}
> +
> +	switch (opt) {
>  	case Opt_logbufs:
> -		if (match_int(args, &mp->m_logbufs))
> -			return -EINVAL;
> +		mp->m_logbufs = result.uint_32;
>  		break;
>  	case Opt_logbsize:
> -		if (match_kstrtoint(args, 10, &mp->m_logbsize))
> +		if (suffix_kstrtoint(param->string, 10, &mp->m_logbsize))
>  			return -EINVAL;
>  		break;
>  	case Opt_logdev:
>  		kfree(mp->m_logname);
> -		mp->m_logname = match_strdup(args);
> +		mp->m_logname = kstrdup(param->string, GFP_KERNEL);
>  		if (!mp->m_logname)
>  			return -ENOMEM;
>  		break;
>  	case Opt_rtdev:
>  		kfree(mp->m_rtname);
> -		mp->m_rtname = match_strdup(args);
> +		mp->m_rtname = kstrdup(param->string, GFP_KERNEL);
>  		if (!mp->m_rtname)
>  			return -ENOMEM;
>  		break;
>  	case Opt_allocsize:
> -		if (match_kstrtoint(args, 10, &iosize))
> +		if (suffix_kstrtoint(param->string, 10, &iosize))
>  			return -EINVAL;
> -		*iosizelog = ffs(iosize) - 1;
> +		ctx->iosizelog = ffs(iosize) - 1;
>  		break;
>  	case Opt_grpid:
>  	case Opt_bsdgroups:
> @@ -264,12 +267,10 @@ xfs_parse_param(
>  		mp->m_flags |= XFS_MOUNT_SWALLOC;
>  		break;
>  	case Opt_sunit:
> -		if (match_int(args, dsunit))
> -			return -EINVAL;
> +		ctx->dsunit = result.uint_32;
>  		break;
>  	case Opt_swidth:
> -		if (match_int(args, dswidth))
> -			return -EINVAL;
> +		ctx->dswidth = result.uint_32;
>  		break;
>  	case Opt_inode32:
>  		mp->m_flags |= XFS_MOUNT_SMALL_INUMS;
> @@ -348,7 +349,7 @@ xfs_parse_param(
>  		break;
>  #endif
>  	default:
> -		xfs_warn(mp, "unknown mount option [%s].", p);
> +		xfs_warn(mp, "unknown mount option [%s].", param->key);
>  		return -EINVAL;
>  	}
>  
> @@ -373,10 +374,13 @@ 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;
> +
> +	memset(&fc, 0, sizeof(fc));
> +	memset(&context, 0, sizeof(context));
> +	fc.fs_private = &context;
> +	fc.s_fs_info = mp;
>  
>  	/*
>  	 * set up the mount name first so all the errors will refer to the
> @@ -413,16 +417,34 @@ xfs_parseargs(
>  		goto done;
>  
>  	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.string = NULL;
> +		param.size = 0;
> +
> +		value = strchr(p, '=');
> +		if (value) {
> +			*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;
>  	}
>  
> @@ -435,7 +457,8 @@ xfs_parseargs(
>  		return -EINVAL;
>  	}
>  
> -	if ((mp->m_flags & XFS_MOUNT_NOALIGN) && (dsunit || dswidth)) {
> +	if ((mp->m_flags & XFS_MOUNT_NOALIGN) &&
> +	    (ctx->dsunit || ctx->dswidth)) {
>  		xfs_warn(mp,
>  	"sunit and swidth options incompatible with the noalign option");
>  		return -EINVAL;
> @@ -448,28 +471,28 @@ xfs_parseargs(
>  	}
>  #endif
>  
> -	if ((dsunit && !dswidth) || (!dsunit && dswidth)) {
> +	if ((ctx->dsunit && !ctx->dswidth) || (!ctx->dsunit && ctx->dswidth)) {
>  		xfs_warn(mp, "sunit and swidth must be specified together");
>  		return -EINVAL;
>  	}
>  
> -	if (dsunit && (dswidth % dsunit != 0)) {
> +	if (ctx->dsunit && (ctx->dswidth % ctx->dsunit != 0)) {
>  		xfs_warn(mp,
>  	"stripe width (%d) must be a multiple of the stripe unit (%d)",
> -			dswidth, dsunit);
> +			ctx->dswidth, ctx->dsunit);
>  		return -EINVAL;
>  	}
>  
>  done:
> -	if (dsunit && !(mp->m_flags & XFS_MOUNT_NOALIGN)) {
> +	if (ctx->dsunit && !(mp->m_flags & XFS_MOUNT_NOALIGN)) {
>  		/*
>  		 * At this point the superblock has not been read
>  		 * in, therefore we do not know the block size.
>  		 * Before the mount call ends we will convert
>  		 * these to FSBs.
>  		 */
> -		mp->m_dalign = dsunit;
> -		mp->m_swidth = dswidth;
> +		mp->m_dalign = ctx->dsunit;
> +		mp->m_swidth = ctx->dswidth;
>  	}
>  
>  	if (mp->m_logbufs != -1 &&
> @@ -491,18 +514,18 @@ xfs_parseargs(
>  		return -EINVAL;
>  	}
>  
> -	if (iosizelog) {
> -		if (iosizelog > XFS_MAX_IO_LOG ||
> -		    iosizelog < XFS_MIN_IO_LOG) {
> +	if (ctx->iosizelog) {
> +		if (ctx->iosizelog > XFS_MAX_IO_LOG ||
> +		    ctx->iosizelog < XFS_MIN_IO_LOG) {
>  			xfs_warn(mp, "invalid log iosize: %d [not %d-%d]",
> -				iosizelog, XFS_MIN_IO_LOG,
> +				ctx->iosizelog, XFS_MIN_IO_LOG,
>  				XFS_MAX_IO_LOG);
>  			return -EINVAL;
>  		}
>  
>  		mp->m_flags |= XFS_MOUNT_DFLT_IOSIZE;
> -		mp->m_readio_log = iosizelog;
> -		mp->m_writeio_log = iosizelog;
> +		mp->m_readio_log = ctx->iosizelog;
> +		mp->m_writeio_log = ctx->iosizelog;
>  	}
>  
>  	return 0;
>