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Commit 3993baeb authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: introduce the CoW fork 



Introduce a new in-core fork for storing copy-on-write delalloc
reservations and allocated extents that are in the process of being
written out.

Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent 11715a21

fs/xfs/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -90,6 +90,7 @@ xfs-y += xfs_aops.o \ 
				   xfs_message.o \

				   xfs_mount.o \

				   xfs_mru_cache.o \

				   xfs_reflink.o \

				   xfs_stats.o \

				   xfs_super.o \

				   xfs_symlink.o \

fs/xfs/libxfs/xfs_bmap.c

+20 −7
Original line number Diff line number Diff line
@@ -2924,6 +2924,7 @@ xfs_bmap_add_extent_hole_real( 
	ASSERT(!isnullstartblock(new->br_startblock));

	ASSERT(!bma->cur ||

	       !(bma->cur->bc_private.b.flags & XFS_BTCUR_BPRV_WASDEL));

	ASSERT(whichfork != XFS_COW_FORK);



	XFS_STATS_INC(mp, xs_add_exlist);
@@ -4072,12 +4073,11 @@ xfs_bmapi_read( 
	int			error;

	int			eof;

	int			n = 0;

	int			whichfork = (flags & XFS_BMAPI_ATTRFORK) ?

						XFS_ATTR_FORK : XFS_DATA_FORK;

	int			whichfork = xfs_bmapi_whichfork(flags);



	ASSERT(*nmap >= 1);

	ASSERT(!(flags & ~(XFS_BMAPI_ATTRFORK|XFS_BMAPI_ENTIRE|

			   XFS_BMAPI_IGSTATE)));

			   XFS_BMAPI_IGSTATE|XFS_BMAPI_COWFORK)));

	ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED|XFS_ILOCK_EXCL));



	if (unlikely(XFS_TEST_ERROR(
@@ -4095,6 +4095,16 @@ xfs_bmapi_read( 


	ifp = XFS_IFORK_PTR(ip, whichfork);



	/* No CoW fork?  Return a hole. */

	if (whichfork == XFS_COW_FORK && !ifp) {

		mval->br_startoff = bno;

		mval->br_startblock = HOLESTARTBLOCK;

		mval->br_blockcount = len;

		mval->br_state = XFS_EXT_NORM;

		*nmap = 1;

		return 0;

	}



	if (!(ifp->if_flags & XFS_IFEXTENTS)) {

		error = xfs_iread_extents(NULL, ip, whichfork);

		if (error)
@@ -4368,8 +4378,7 @@ xfs_bmapi_convert_unwritten( 
	xfs_filblks_t		len,

	int			flags)

{

	int			whichfork = (flags & XFS_BMAPI_ATTRFORK) ?

						XFS_ATTR_FORK : XFS_DATA_FORK;

	int			whichfork = xfs_bmapi_whichfork(flags);

	struct xfs_ifork	*ifp = XFS_IFORK_PTR(bma->ip, whichfork);

	int			tmp_logflags = 0;

	int			error;
@@ -4385,6 +4394,8 @@ xfs_bmapi_convert_unwritten( 
			(XFS_BMAPI_PREALLOC | XFS_BMAPI_CONVERT))

		return 0;



	ASSERT(whichfork != XFS_COW_FORK);



	/*

	 * Modify (by adding) the state flag, if writing.

	 */
@@ -4795,6 +4806,8 @@ xfs_bmap_del_extent( 


	if (whichfork == XFS_ATTR_FORK)

		state |= BMAP_ATTRFORK;

	else if (whichfork == XFS_COW_FORK)

		state |= BMAP_COWFORK;



	ifp = XFS_IFORK_PTR(ip, whichfork);

	ASSERT((*idx >= 0) && (*idx < ifp->if_bytes /
@@ -5133,8 +5146,8 @@ __xfs_bunmapi( 


	trace_xfs_bunmap(ip, bno, len, flags, _RET_IP_);



	whichfork = (flags & XFS_BMAPI_ATTRFORK) ?

		XFS_ATTR_FORK : XFS_DATA_FORK;

	whichfork = xfs_bmapi_whichfork(flags);

	ASSERT(whichfork != XFS_COW_FORK);

	ifp = XFS_IFORK_PTR(ip, whichfork);

	if (unlikely(

	    XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS &&

fs/xfs/libxfs/xfs_bmap.h

+19 −3
Original line number Diff line number Diff line
@@ -107,6 +107,9 @@ struct xfs_extent_free_item 
 */

#define XFS_BMAPI_REMAP		0x100



/* Map something in the CoW fork. */

#define XFS_BMAPI_COWFORK	0x200



#define XFS_BMAPI_FLAGS \

	{ XFS_BMAPI_ENTIRE,	"ENTIRE" }, \

	{ XFS_BMAPI_METADATA,	"METADATA" }, \
@@ -116,12 +119,23 @@ struct xfs_extent_free_item 
	{ XFS_BMAPI_CONTIG,	"CONTIG" }, \

	{ XFS_BMAPI_CONVERT,	"CONVERT" }, \

	{ XFS_BMAPI_ZERO,	"ZERO" }, \

	{ XFS_BMAPI_REMAP,	"REMAP" }

	{ XFS_BMAPI_REMAP,	"REMAP" }, \

	{ XFS_BMAPI_COWFORK,	"COWFORK" }





static inline int xfs_bmapi_aflag(int w)

{

	return (w == XFS_ATTR_FORK ? XFS_BMAPI_ATTRFORK : 0);

	return (w == XFS_ATTR_FORK ? XFS_BMAPI_ATTRFORK :

	       (w == XFS_COW_FORK ? XFS_BMAPI_COWFORK : 0));

}



static inline int xfs_bmapi_whichfork(int bmapi_flags)

{

	if (bmapi_flags & XFS_BMAPI_COWFORK)

		return XFS_COW_FORK;

	else if (bmapi_flags & XFS_BMAPI_ATTRFORK)

		return XFS_ATTR_FORK;

	return XFS_DATA_FORK;

}



/*
@@ -142,13 +156,15 @@ static inline int xfs_bmapi_aflag(int w) 
#define BMAP_LEFT_VALID		(1 << 6)

#define BMAP_RIGHT_VALID	(1 << 7)

#define BMAP_ATTRFORK		(1 << 8)

#define BMAP_COWFORK		(1 << 9)



#define XFS_BMAP_EXT_FLAGS \

	{ BMAP_LEFT_CONTIG,	"LC" }, \

	{ BMAP_RIGHT_CONTIG,	"RC" }, \

	{ BMAP_LEFT_FILLING,	"LF" }, \

	{ BMAP_RIGHT_FILLING,	"RF" }, \

	{ BMAP_ATTRFORK,	"ATTR" }

	{ BMAP_ATTRFORK,	"ATTR" }, \

	{ BMAP_COWFORK,		"COW" }





/*

fs/xfs/libxfs/xfs_bmap_btree.c

+1 −0
Original line number Diff line number Diff line
@@ -777,6 +777,7 @@ xfs_bmbt_init_cursor( 
{

	struct xfs_ifork	*ifp = XFS_IFORK_PTR(ip, whichfork);

	struct xfs_btree_cur	*cur;

	ASSERT(whichfork != XFS_COW_FORK);



	cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_SLEEP);

fs/xfs/libxfs/xfs_inode_fork.c

+44 −3
Original line number Diff line number Diff line
@@ -206,9 +206,14 @@ xfs_iformat_fork( 
		XFS_ERROR_REPORT("xfs_iformat(7)", XFS_ERRLEVEL_LOW, ip->i_mount);

		return -EFSCORRUPTED;

	}

	if (error) {

	if (error)

		return error;



	if (xfs_is_reflink_inode(ip)) {

		ASSERT(ip->i_cowfp == NULL);

		xfs_ifork_init_cow(ip);

	}



	if (!XFS_DFORK_Q(dip))

		return 0;
@@ -247,6 +252,9 @@ xfs_iformat_fork( 
	if (error) {

		kmem_zone_free(xfs_ifork_zone, ip->i_afp);

		ip->i_afp = NULL;

		if (ip->i_cowfp)

			kmem_zone_free(xfs_ifork_zone, ip->i_cowfp);

		ip->i_cowfp = NULL;

		xfs_idestroy_fork(ip, XFS_DATA_FORK);

	}

	return error;
@@ -761,6 +769,9 @@ xfs_idestroy_fork( 
	if (whichfork == XFS_ATTR_FORK) {

		kmem_zone_free(xfs_ifork_zone, ip->i_afp);

		ip->i_afp = NULL;

	} else if (whichfork == XFS_COW_FORK) {

		kmem_zone_free(xfs_ifork_zone, ip->i_cowfp);

		ip->i_cowfp = NULL;

	}

}
@@ -948,6 +959,19 @@ xfs_iext_get_ext( 
	}

}



/* Convert bmap state flags to an inode fork. */

struct xfs_ifork *

xfs_iext_state_to_fork(

	struct xfs_inode	*ip,

	int			state)

{

	if (state & BMAP_COWFORK)

		return ip->i_cowfp;

	else if (state & BMAP_ATTRFORK)

		return ip->i_afp;

	return &ip->i_df;

}



/*

 * Insert new item(s) into the extent records for incore inode

 * fork 'ifp'.  'count' new items are inserted at index 'idx'.
@@ -960,7 +984,7 @@ xfs_iext_insert( 
	xfs_bmbt_irec_t	*new,		/* items to insert */

	int		state)		/* type of extent conversion */

{

	xfs_ifork_t	*ifp = (state & BMAP_ATTRFORK) ? ip->i_afp : &ip->i_df;

	xfs_ifork_t	*ifp = xfs_iext_state_to_fork(ip, state);

	xfs_extnum_t	i;		/* extent record index */



	trace_xfs_iext_insert(ip, idx, new, state, _RET_IP_);
@@ -1210,7 +1234,7 @@ xfs_iext_remove( 
	int		ext_diff,	/* number of extents to remove */

	int		state)		/* type of extent conversion */

{

	xfs_ifork_t	*ifp = (state & BMAP_ATTRFORK) ? ip->i_afp : &ip->i_df;

	xfs_ifork_t	*ifp = xfs_iext_state_to_fork(ip, state);

	xfs_extnum_t	nextents;	/* number of extents in file */

	int		new_size;	/* size of extents after removal */
@@ -1955,3 +1979,20 @@ xfs_iext_irec_update_extoffs( 
		ifp->if_u1.if_ext_irec[i].er_extoff += ext_diff;

	}

}



/*

 * Initialize an inode's copy-on-write fork.

 */

void

xfs_ifork_init_cow(

	struct xfs_inode	*ip)

{

	if (ip->i_cowfp)

		return;



	ip->i_cowfp = kmem_zone_zalloc(xfs_ifork_zone,

				       KM_SLEEP | KM_NOFS);

	ip->i_cowfp->if_flags = XFS_IFEXTENTS;

	ip->i_cformat = XFS_DINODE_FMT_EXTENTS;

	ip->i_cnextents = 0;

}