Commit 4887e531 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Chandan Babu R
Browse files

xfs: compile out v4 support if disabled 



Add a few strategic IS_ENABLED statements to let the compiler eliminate
unused code when CONFIG_XFS_SUPPORT_V4 is disabled.

This saves multiple kilobytes of .text in my .config:

$ size xfs.o.*
text	   data	    bss	    dec	    hex	filename
1363633	 294836	    592	1659061	 1950b5	xfs.o.new
1371453	 294868	    592	1666913	 196f61	xfs.o.old

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatar"Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: default avatarChandan Babu R <chandanbabu@kernel.org>
parent c0ac6cb2

fs/xfs/xfs_mount.h

+31 −9
Original line number Diff line number Diff line
@@ -332,19 +332,10 @@ static inline void xfs_add_ ## name (struct xfs_mount *mp) \ 
__XFS_ADD_FEAT(attr, ATTR)

__XFS_HAS_FEAT(nlink, NLINK)

__XFS_ADD_FEAT(quota, QUOTA)

__XFS_HAS_FEAT(align, ALIGN)

__XFS_HAS_FEAT(dalign, DALIGN)

__XFS_HAS_FEAT(logv2, LOGV2)

__XFS_HAS_FEAT(sector, SECTOR)

__XFS_HAS_FEAT(extflg, EXTFLG)

__XFS_HAS_FEAT(asciici, ASCIICI)

__XFS_HAS_FEAT(lazysbcount, LAZYSBCOUNT)

__XFS_ADD_FEAT(attr2, ATTR2)

__XFS_HAS_FEAT(parent, PARENT)

__XFS_ADD_FEAT(projid32, PROJID32)

__XFS_HAS_FEAT(crc, CRC)

__XFS_HAS_FEAT(v3inodes, V3INODES)

__XFS_HAS_FEAT(pquotino, PQUOTINO)

__XFS_HAS_FEAT(ftype, FTYPE)

__XFS_HAS_FEAT(finobt, FINOBT)

__XFS_HAS_FEAT(rmapbt, RMAPBT)
@@ -358,6 +349,37 @@ __XFS_HAS_FEAT(needsrepair, NEEDSREPAIR) 
__XFS_HAS_FEAT(large_extent_counts, NREXT64)

__XFS_HAS_FEAT(exchange_range, EXCHANGE_RANGE)



/*

 * Some features are always on for v5 file systems, allow the compiler to

 * eliminiate dead code when building without v4 support.

 */

#define __XFS_HAS_V4_FEAT(name, NAME) \

static inline bool xfs_has_ ## name (struct xfs_mount *mp) \

{ \

	return !IS_ENABLED(CONFIG_XFS_SUPPORT_V4) || \

		(mp->m_features & XFS_FEAT_ ## NAME); \

}



#define __XFS_ADD_V4_FEAT(name, NAME) \

	__XFS_HAS_V4_FEAT(name, NAME); \

static inline void xfs_add_ ## name (struct xfs_mount *mp) \

{ \

	if (IS_ENABLED(CONFIG_XFS_SUPPORT_V4)) { \

		mp->m_features |= XFS_FEAT_ ## NAME; \

		xfs_sb_version_add ## name(&mp->m_sb); \

	} \

}



__XFS_HAS_V4_FEAT(align, ALIGN)

__XFS_HAS_V4_FEAT(logv2, LOGV2)

__XFS_HAS_V4_FEAT(extflg, EXTFLG)

__XFS_HAS_V4_FEAT(lazysbcount, LAZYSBCOUNT)

__XFS_ADD_V4_FEAT(attr2, ATTR2)

__XFS_ADD_V4_FEAT(projid32, PROJID32)

__XFS_HAS_V4_FEAT(v3inodes, V3INODES)

__XFS_HAS_V4_FEAT(crc, CRC)

__XFS_HAS_V4_FEAT(pquotino, PQUOTINO)



/*

 * Mount features

 *

fs/xfs/xfs_super.c

+13 −9
Original line number Diff line number Diff line
@@ -1580,17 +1580,21 @@ xfs_fs_fill_super( 
	if (error)

		goto out_free_sb;



	/* V4 support is undergoing deprecation. */

	if (!xfs_has_crc(mp)) {

#ifdef CONFIG_XFS_SUPPORT_V4

		xfs_warn_once(mp,

	"Deprecated V4 format (crc=0) will not be supported after September 2030.");

#else

	/*

	 * V4 support is undergoing deprecation.

	 *

	 * Note: this has to use an open coded m_features check as xfs_has_crc

	 * always returns false for !CONFIG_XFS_SUPPORT_V4.

	 */

	if (!(mp->m_features & XFS_FEAT_CRC)) {

		if (!IS_ENABLED(CONFIG_XFS_SUPPORT_V4)) {

			xfs_warn(mp,

	"Deprecated V4 format (crc=0) not supported by kernel.");

			error = -EINVAL;

			goto out_free_sb;

#endif

		}

		xfs_warn_once(mp,

	"Deprecated V4 format (crc=0) will not be supported after September 2030.");

	}



	/* ASCII case insensitivity is undergoing deprecation. */