common/hsmapi.c

/*
 * Copyright (c) 2000-2004 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <uuid/uuid.h>
#include <attr/attributes.h>
#include <xfs/xfs.h>
#include <xfs/jdm.h>

#include <string.h>

#include "config.h"

#include "types.h"
#include "hsmapi.h"
#include "mlog.h"

/* This version of the HSM API supports the DMF attribute used in the initial
 * DMF release, as well as the attribute used in the pseudo multiple managed
 * region DMF release.
*/

/* DMF attribute name, size, and format as stored within XFS. (Stolen directly
   from "dmfsapi/dmf_dmattr.H".
*/

#define	DMF_ATTR_NAME	"SGI_DMI_DMFATTR"	/* name of DMF's attr */

typedef	struct {
	u_char	fsys;		/* filesystem type */
	u_char	version;	/* attribute format version */
	u_char	state[2];	/* dm_state in MSB form */
	u_char	flags[2];	/* dm_flags in MSB form */
	u_char	bfid[16];	/* Bitfile ID in MSB form */
} XFSattrvalue0_t;

typedef	struct {
	u_char	rg_offset[8];	/* region offset in MSB form */
	u_char	rg_size[8];	/* region length in MSB form */
	u_char	rg_state[2];	/* region dm_state in MSB form */
	u_char	rg_flags;	/* managed region event bits */
	u_char	rg_fbits;	/* region flag bits */
} XFSattrregion_t;

typedef	struct {
	u_char	fsys;		/* filesystem type */
	u_char	version;	/* attribute format version */
	u_char	state[2];	/* global dm_state in MSB form */
	u_char	flags[2];	/* global dm_flags in MSB form */
	u_char	bfid[16];	/* Bitfile ID in MSB form. */
	u_char	sitetag[4];	/* site tag */
	u_char	regcnt[2];	/* number of regions in MSB form */
} XFSattrvalue1_t;

#define	MIN_FORMAT1_ATTR_LEN	(sizeof(XFSattrvalue1_t) + \
				  sizeof(XFSattrregion_t))

/* supported fsys values */

/* XFS DMAPI (w/o MMR) */
#define	FSYS_TYPE_XFS		1

/* supported version values */

/* original DMF attr format */
#define	DMF_ATTR_FORMAT_0	0
/* DMF attr with multiple regions (real or pseudo) or with a non-zero
 * site tag. attrs of this format consist of a XFSattrvalue1_t struct
 * followed by 1 or more XFSattrregion_t structs */
#define	DMF_ATTR_FORMAT_1	1

/* Interesting state field values */

#define	DMF_ST_DUALSTATE	2	/* file has backups plus online data */
#define	DMF_ST_OFFLINE		3	/* file has backups, no online data */
#define	DMF_ST_UNMIGRATING	4	/* file data is being staged in */
#define	DMF_ST_NOMIGR		5	/* file should not be migrated */
#define	DMF_ST_PARTIAL		6	/* file has backups plus parts online */

/* DM_EVENT_* are defined in <xfs/dmapi.h>. Trying to avoid a dmapi dependency
 * in xfsdump since dmapi is not commonly used, yet this code needs to know some
 * of the event bits.
 */
#define	DM_EVENT_READ		16
#define	DM_EVENT_WRITE		17
#define	DM_EVENT_TRUNCATE	18
#define	DM_EVENT_DESTROY	20

 /* Interesting bit combinations within the bs_dmevmask field of xfs_bstat_t:
 * OFL, UNM, and PAR files have exactly these bits set.
 * DUL and MIG files have all but the DM_EVENT_READ bit set */
#define DMF_EV_BITS	((1<<DM_EVENT_DESTROY) | \
			  (1<<DM_EVENT_READ)    | \
			  (1<<DM_EVENT_WRITE)   | \
			  (1<<DM_EVENT_TRUNCATE))

/* OFL file's managed region event flags */
#define DMF_MR_FLAGS	(0x1 | 0x2 | 0x4)

/* The following definitions provide the internal format of the hsm_fs_ctxt_t
   and hsm_f_ctxt_t structures, respectively.
*/

typedef	struct	{
	int		dumpversion;
	jdm_fshandle_t  *fshanp;
} dmf_fs_ctxt_t;

typedef	struct	{
	dmf_fs_ctxt_t	fsys;
	off64_t		filesize;
	int		candidate;
	int		attrlen;
	char		attrval[5000];	/* sized bigger than any poss. value */
} dmf_f_ctxt_t;

/******************************************************************************
* Name
*       msb_store - store a variable to u_char array in MSB format
*
* Returns
*	void
******************************************************************************/
static inline void
msb_store(
	u_char		*dest,
	uint64_t	src,
	int		length)
{
        int             i;

        for (i = length - 1; i >= 0; i--) {
                dest[i] = (u_char)(src & 0xff);
                src >>= 8;
        }
}

/******************************************************************************
* Name
*       msb_load - load a variable from a u_char array in MSB format
*
* Returns
*	value
******************************************************************************/
static inline uint64_t
msb_load(
	u_char		*src,
	int		length)
{
        uint64_t        tmp = 0;
        int             i;

        for (i = 0; i < length; i++) {
                tmp = (tmp << 8) | src[i];
        }
        return tmp;
}

/******************************************************************************
* Name
*	HsmInitFsysContext - allocate and initialize an HSM filesystem context
*
* Description
*	HsmInitFsysContext allocates and initializes an HSM filesystem
*	context to hold all filesystem information that might later be needed
*	by other HSM routines.  The context is read-only, and can be shared
*	by multiple xfsdump dump streams.  It should eventually be freed by
*	calling HsmDeleteFsysContext().  The caller must provide the mount
*	point of the filesystem to be dumped and the HSM API version that
*	xfsdump was compiled with.
*
*	Note: The restore routines do not require an HSM filesystem context.
*
* Returns
*	!= NULL, then a pointer to the filesystem context that was allocated.
*	== NULL, either the HSM libary is not compatible with xfsdump, or
*	      the filesystem is not under HSM management.
******************************************************************************/

extern hsm_fs_ctxt_t *
HsmInitFsysContext(
const	char		*mountpoint,
	int		dumpversion)
{
	dmf_fs_ctxt_t	*dmf_fs_ctxtp;

	if (dumpversion != HSM_API_VERSION_1) {
		return NULL;		/* we can't handle this version */
	}

	/* Malloc space for a filesystem context, and initialize any fields
	   needed later by other routines.
	*/

	if ((dmf_fs_ctxtp = malloc(sizeof(dmf_fs_ctxt_t))) == NULL) {
		return NULL;
	}
	dmf_fs_ctxtp->dumpversion = dumpversion;

	/* Get the filesystem's handle for later use in building file
	   handles in HsmInitFileContext.
	*/
	dmf_fs_ctxtp->fshanp = jdm_getfshandle((char *)mountpoint);
	if (dmf_fs_ctxtp->fshanp == NULL) {
		free(dmf_fs_ctxtp);
		return NULL;
	}

	return (hsm_fs_ctxt_t *)dmf_fs_ctxtp;
}


/******************************************************************************
* Name
*	HsmDeleteFsysContext - delete an HSM filesystem context
*
* Description
*	HsmDeleteFsysContext releases all storage previously allocated to a
*	HSM filesystem context via HsmInitFsysContext.
*
* Returns
*	None.
******************************************************************************/

extern void
HsmDeleteFsysContext(
	hsm_fs_ctxt_t	*contextp)
{
	free(contextp);
}


/******************************************************************************
* Name
*	HsmEstimateFileSpace - return estimated offline file size
*
* Description
*	HsmEstimateFileSpace is called from within estimate_dump_space() only
*	if -a is selected.  It estimates the number of bytes needed to dump
*	the file assuming that all dual-residency data will be dumped as holes.
*
* Returns
*	!= 0, then *bytes contains the estimated size of the file in bytes.
*	== 0, then no estimate made.  Caller should use his default estimator.
******************************************************************************/

extern int
HsmEstimateFileSpace(
	hsm_fs_ctxt_t	*fscontextp,
	hsm_f_ctxt_t	*fcontextp,
const	xfs_bstat_t	*statp,
	off64_t		*bytes,
	int		accurate)
{
	/* If the estimate needs to be accurate, then we'll have to
	 * pay the price and read the DMF attribute, if there is one,
	 * to determine exactly what DMF state the file is in. Otherwise,
	 * make a guess based on information in the bstat. If a
	 * hsm_f_ctxt_t was provided, an accurate estimate is free.
	 */
	if (fcontextp) {
		dmf_f_ctxt_t	*dmf_f_ctxt = (dmf_f_ctxt_t *)fcontextp;

		if (dmf_f_ctxt->candidate) {
			*bytes = 0;	/* treat the entire file as offline */
			return 1;
		} else {
			return 0;
		}
	} else if (accurate) {
		dmf_fs_ctxt_t	*dmf_fs_ctxtp = (dmf_fs_ctxt_t *)fscontextp;
		dmf_f_ctxt_t	dmf_f_ctxt;

		/* This is an implicit HsmAllocateFileContext call. */

		dmf_f_ctxt.fsys = *dmf_fs_ctxtp;
		dmf_f_ctxt.candidate = 0;

		/* Initialize the file context to determine the file's state. */

		if (HsmInitFileContext((hsm_f_ctxt_t *)&dmf_f_ctxt, statp)) {
			return 0;
		}

		/* If the file is dualstate, make it appear offline. */

		if (dmf_f_ctxt.candidate) {
			*bytes = 0;	/* treat the entire file as offline */
			return 1;
		} else {
			return 0;
		}
	} else {
		/* This code is assuming that there are no MIG files, and so any
		   file with DMAPI event bits set will be dumped as OFL. The
		   non-dir dump size estimation will be somewhat low if there
		   are MIG files.
		 */
		if ((statp->bs_mode & S_IFMT) != S_IFREG) {
			return 0;       /* not a regular file */
		}
		if ((statp->bs_xflags & XFS_XFLAG_HASATTR) == 0) {
			return 0;       /* no DMF attribute can possibly exist */
		}
		if ((statp->bs_dmevmask & DMF_EV_BITS) == 0) {
			return 0;
		}

		*bytes = 0;
		return 1;
	}
}


/******************************************************************************
* Name
*	HsmEstimateFileOffset - return estimated file offset
*
* Description
*	HsmEstimateFileOffset is called from within quantity2offset() only
*	if -a is selected.  It estimates the offset within the file that has
*	'bytecount' bytes of physical data preceding it assuming that all
*	dual-residency data in the file will be dumped as holes.
*
* Returns
*	!= 0, then *byteoffset contains the estimated offset within the file.
*	== 0, then no estimate made.  Caller should use his default estimator.
******************************************************************************/

/* ARGSUSED */
extern int
HsmEstimateFileOffset(
	hsm_fs_ctxt_t	*contextp,
const	xfs_bstat_t	*statp,
	off64_t		bytecount,
	off64_t		*byteoffset)
{
	dmf_fs_ctxt_t	*dmf_fs_ctxtp = (dmf_fs_ctxt_t *)contextp;
	dmf_f_ctxt_t	dmf_f_ctxt;

	/* This is an implicit HsmAllocateFileContext call. */

	dmf_f_ctxt.fsys = *dmf_fs_ctxtp;
	dmf_f_ctxt.candidate = 0;

	/* Initialize the file context to determine the file's state. */

	if (HsmInitFileContext((hsm_f_ctxt_t *)&dmf_f_ctxt, statp)) {
		return 0;
	}

	/* If the file is dualstate, make it appear offline. */

	if (dmf_f_ctxt.candidate) {
		*byteoffset = statp->bs_size;
		return 1;
	} else {
		return 0;
	}
}


/******************************************************************************
* Name
*	HsmAllocateFileContext - allocate an HSM file context
*
* Description
*	HsmAllocateFileContext mallocs the maximum-sized file context that
*	might later needed by HsmInitFileContext().  The context is
*	read-write.  Each xfsdump stream must have its own file context.  This
*	context should eventually be freed by calling HsmDeleteFileContext().
*	The caller must provide the HSM filesystem context for the filesystem
*	being dumped.
*
*	Note: The restore routines do not require an HSM file context.
*
* Returns
*	!= NULL, then a pointer to the file context that was allocated.
******************************************************************************/

extern hsm_f_ctxt_t *
HsmAllocateFileContext(
	hsm_fs_ctxt_t	*contextp)
{
	dmf_f_ctxt_t	*dmf_f_ctxtp;

	if ((dmf_f_ctxtp = malloc(sizeof(dmf_f_ctxt_t))) == NULL) {
		return NULL;
	}

	/* Save the filesystem information in the file context. */

	dmf_f_ctxtp->fsys = *(dmf_fs_ctxt_t *)contextp;
	dmf_f_ctxtp->candidate = 0;

	return (hsm_f_ctxt_t *)dmf_f_ctxtp;
}


/******************************************************************************
* Name
*	HsmDeleteFileContext - delete a previously created HSM file context
*
* Description
*	HsmDeleteFileContext releases all storage previously allocated to a
*	HSM file context via HsmAllocateFileContext.
*
* Returns
*	None.
******************************************************************************/

extern void
HsmDeleteFileContext(
	hsm_f_ctxt_t	*contextp)
{
	free(contextp);
}


/******************************************************************************
* Name
*	HsmInitFileContext - initialize the HSM context for a particular file
*
* Description
*	HsmInitFileContext initializes an existing HSM file context for
*	subsequent operations on a particular regular file.  Other HSM routines
*	use the context to access information collected by HsmInitFileContext
*	about the file rather than having to recollect the file's information
*	on each call.
*
* Returns
*	== 0, context was created.
*	!= 0, if something is wrong with the file and it should not be dumped.
******************************************************************************/

extern int
HsmInitFileContext(
	hsm_f_ctxt_t	*contextp,
const	xfs_bstat_t	*statp)
{
	dmf_f_ctxt_t	*dmf_f_ctxtp = (dmf_f_ctxt_t *)contextp;
	XFSattrvalue0_t	*dmfattrp;
	int		state;
	int		error;
	attr_multiop_t	attr_op;

	dmf_f_ctxtp->candidate = 0; /* assume file will NOT be of interest */

	/* Try and rule out a dualstate inode by doing some quick tests. */

	if ((statp->bs_mode & S_IFMT) != S_IFREG) {
		return 0;	/* not a regular file */
	}
	if ((statp->bs_xflags & XFS_XFLAG_HASATTR) == 0) {
		return 0;	/* no DMF attribute exists */
	}
	if ((statp->bs_dmevmask & DMF_EV_BITS) == 0) {
		return 0;	/* no interesting DMAPI bits set */
	}

	/* We have a likely candidate, so we have to pay the price and look
	   for the DMF attribute.  (It could be in a disk block separate from
	   the inode.)
	*/
	attr_op.am_opcode    = ATTR_OP_GET;
	attr_op.am_error     = 0;
	attr_op.am_attrname  = DMF_ATTR_NAME;
	attr_op.am_attrvalue = dmf_f_ctxtp->attrval;
	attr_op.am_length    = sizeof(dmf_f_ctxtp->attrval);
	attr_op.am_flags     = ATTR_ROOT;

	error = jdm_attr_multi(dmf_f_ctxtp->fsys.fshanp,
			       (xfs_bstat_t *)statp,
			       (char *)&attr_op,
			       1,
			       0);
	if (error || attr_op.am_error)
		return 0; /* no DMF attribute */

	dmf_f_ctxtp->attrlen = attr_op.am_length;
	dmfattrp = (XFSattrvalue0_t *)dmf_f_ctxtp->attrval;

	if (dmfattrp->fsys != FSYS_TYPE_XFS)
		return 0; /* unsupported filesystem version */

	switch(dmfattrp->version) {
	case DMF_ATTR_FORMAT_0:
		if (dmf_f_ctxtp->attrlen != sizeof(XFSattrvalue0_t))
			return 0; /* wrong size */
		break;
	case DMF_ATTR_FORMAT_1:
		if (dmf_f_ctxtp->attrlen < MIN_FORMAT1_ATTR_LEN)
			return 0; /* wrong size */
		break;
	default:
		return 0; /* unsupported attr version */
	}

	state = (int)msb_load(dmfattrp->state, sizeof(dmfattrp->state));
	switch (state) {
	case DMF_ST_DUALSTATE:
	case DMF_ST_UNMIGRATING:
	case DMF_ST_PARTIAL:
	case DMF_ST_OFFLINE:
		/* We have a DMF file that can be treated as offline */
		dmf_f_ctxtp->candidate = 1;
		dmf_f_ctxtp->filesize = statp->bs_size;
		break;

	default:
		break;
	}
	return 0;
}


/******************************************************************************
* Name
*	HsmModifyInode - modify a xfs_bstat_t to make a file appear offline
*
* Description
*	HsmModifyInode uses the context provided by a previous
*	HsmInitFileContext call to determine how to modify a xfs_bstat_t
*	structure to make a dual-residency HSM file appear to be offline.
*
* Returns
*	!= 0, xfs_bstat_t structure was modified.
*	== 0, if something is wrong with the file and it should not be dumped.
******************************************************************************/

extern int
HsmModifyInode(
	hsm_f_ctxt_t	*contextp,
	xfs_bstat_t	*statp)
{
	dmf_f_ctxt_t	*dmf_f_ctxtp = (dmf_f_ctxt_t *)contextp;

	if (dmf_f_ctxtp->candidate) {
		statp->bs_dmevmask = DMF_EV_BITS;
	}
	return 1;
}


/******************************************************************************
* Name
*	HsmModifyExtentMap - modify getbmapx array to make file appear offline
*
* Description
*	HsmModifyExtentMap uses the context provided by a previous
*	HsmInitFileContext call to determine how to modify a contiguous array
*	of getbmapx structures to make a dual-residency HSM file appear to
*	be offline.
*
* Returns
*	!= 0, getbmapx array was successfully modified.
*	== 0, if something is wrong with the file and it should not be dumped.
******************************************************************************/

extern int
HsmModifyExtentMap(
	hsm_f_ctxt_t	*contextp,
	struct getbmapx	*bmap)
{
	dmf_f_ctxt_t	*dmf_f_ctxtp = (dmf_f_ctxt_t *)contextp;
	int64_t		length;

	if (bmap[0].bmv_entries <= 0) {
		return 1;	/* caller must already be at EOF */
	}

	if (!dmf_f_ctxtp->candidate) {
		return 1;	/* not a dualstate file; dump as normal */
	}

	/* We are dumping a dualstate file.  Make it look like there is only
	   one getbmapx extent and that it contains a hole which extends from
	   the current offset to the end of the file.  The bmap[1].bmv_offset
	   should already be correct.
	*/

	length = BTOBB(dmf_f_ctxtp->filesize) - bmap[1].bmv_offset;

	if (length > 0) {
		bmap[0].bmv_entries = 1;	/* rest of file is one extent */

		bmap[1].bmv_block = -1;		/* convert to a hole */
		bmap[1].bmv_length = length;
	} else {
		bmap[0].bmv_entries = 0;	/* indicate at EOF */
	}

	return 1;
}


/******************************************************************************
* Name
*	HsmFilterExistingAttribute - filter out unwanted extended attributes
*
* Description
*	HsmFilterExistingAttribute uses the context provided by a previous
*	HsmInitFileContext call to determine whether or not the extended
*	attribute with name 'namep' should be included in a file's dump image.
*	(An extended attribute can be modified within the dump by filtering
*	it out with this routine, then adding the new version of the attribute
*	back with HsmAddNewAttribute.)
*
*	Note: this routine must be idempotent.  It is possible that xfsdump
*	will call this routine a second time for the same attribute if after
*	the first call it discovers that there isn't room in its buffer to
*	hold the attribute value.
*
* Returns
*	!= 0, the attribute was successfully examined.  If '*skip_entry' is
*	      non-zero, xfsdump will not add this attribute to the dump.
*	== 0, if something is wrong with the file and it should not be dumped.
******************************************************************************/

extern int
HsmFilterExistingAttribute(
	hsm_f_ctxt_t	*hsm_f_ctxtp,
const	char		*namep,		/* attribute name */
	uint32_t	valuesz,	/* value size */
	int		flag,
	int		*skip_entry)
{
	dmf_f_ctxt_t	*dmf_f_ctxtp = (dmf_f_ctxt_t *)hsm_f_ctxtp;

	*skip_entry = 0;	/* assume we will not remove this attribute */

	if (!dmf_f_ctxtp->candidate) {
		return 1;	/* not a dualstate file */
	}
	if (flag != ATTR_ROOT) {
		return 1;	/* not a root attribute */
	}
	if (strcmp(namep, DMF_ATTR_NAME)) {
		return 1;	/* not the right attribute */
	}

	if (valuesz < sizeof(XFSattrvalue0_t)) {
		return 0;	/* attribute is corrupt */
	}

	/* Remove the existing DMF attribute, as we will later replace it with
	   our own version.
	*/

	*skip_entry = 1;
	return 1;
}


/******************************************************************************
* Name
*	HsmAddNewAttribute - add zero or more HSM attributes to a file's dump
*
* Description
*	HsmAddNewAttribute uses the context provided by a previous
*	HsmInitFileContext call to determine whether or not additional HSM
*	extended attributes need to be added to a file's dump image.  On the
*	first call for a file, 'cursor' will be zero.  xfsdump will increment
*	'cursor' by one each time it asks for a new attribute.  When no more
*	attributes are to be added, '*namepp' should be set to NULL.
*
*	Note: this routine must be idempotent.  It is possible that xfsdump
*	will call this routine a second time using the same cursor value if
*	it discovers that there isn't room in its buffer to hold the attribute
*	value it was given in the first call.
*
* Returns
*	!= 0, call was successful.  If '*namepp' is non-NULL, then it is the
*	      name of an attribute to be added to the file's dump.  '*valuep'
*	      points the the value of the attribute, and '*valueszp' is the
*	      value's size.  If '*namep* is NULL, then there are no more
*	      attributes to be added.
*	== 0, if something is wrong with the file and it should not be dumped.
******************************************************************************/

extern int
HsmAddNewAttribute(
	hsm_f_ctxt_t	*hsm_f_ctxtp,
	int		cursor,
	int		flag,
	char		**namepp,	/* pointer to new attribute name */
	char		**valuepp,	/* pointer to its value */
	uint32_t	*valueszp)	/* pointer to the value size */
{
	dmf_f_ctxt_t	*dmf_f_ctxtp = (dmf_f_ctxt_t *)hsm_f_ctxtp;
	XFSattrvalue1_t	*dmfattr1p = (XFSattrvalue1_t *)dmf_f_ctxtp->attrval;

	*namepp = NULL;		/* assume we won't add an attribute */

	if (!dmf_f_ctxtp->candidate) {
		return 1;	/* not a dualstate file */
	}
	if (flag != ATTR_ROOT) {
		return 1;	/* not in the root attribute section */
	}

	if (cursor > 0) {
		return 1;	/* there is only one attribute to add */
	}

	/* DMF writes format0 (XFSattrvalue0_t) attributes unless:
	 *    - the file has multiple regions
	 *    - the file has a non-zero site tag
	 *
	 * Here we are writing a single region (OFL), so we only dump a
	 * format1 attribute if the file has a non-zero site tag.
	 */
	if (dmfattr1p->version == DMF_ATTR_FORMAT_1 &&
	    msb_load(dmfattr1p->sitetag, sizeof(dmfattr1p->sitetag)) != 0) {
		XFSattrregion_t *reg;
		reg = (XFSattrregion_t *)(dmf_f_ctxtp->attrval +
				           sizeof(XFSattrvalue1_t));
		dmf_f_ctxtp->attrlen = MIN_FORMAT1_ATTR_LEN;

		/* make one offline region the size of the whole file */
		msb_store(dmfattr1p->regcnt, 1, sizeof(dmfattr1p->regcnt));
		msb_store(reg->rg_offset, 0, sizeof(reg->rg_offset));
		msb_store(reg->rg_size, dmf_f_ctxtp->filesize, sizeof(reg->rg_size));
		msb_store(reg->rg_state, DMF_ST_OFFLINE, sizeof(reg->rg_state));
		reg->rg_flags = DMF_MR_FLAGS;
		reg->rg_fbits = 0;
	} else {
		/* writing a format0 attr. ensure correct length and version */
		dmfattr1p->version = DMF_ATTR_FORMAT_0;
		dmf_f_ctxtp->attrlen = sizeof(XFSattrvalue0_t);
	}

	/* set the global state to offline */
	msb_store(dmfattr1p->state, DMF_ST_OFFLINE, sizeof(dmfattr1p->state));

	*valuepp = (char *)dmfattr1p;
	*namepp = DMF_ATTR_NAME;
	*valueszp = dmf_f_ctxtp->attrlen;
	return 1;
}


/******************************************************************************
* Name
*	HsmBeginRestoreFile
*
* Description
*	HsmBeginRestoreFile is called after a file is created but before any
*	data has been restored to it. The hsm_flagp param can be used to
*	keep track of limited state between calls to the HSM restore routines.
*
*	Note that this does not require a filesystem or file context like the
*	HSM calls for xfsdump. This is currently a crude interface to satisfy
*	a specific need. It can be generalized at a later time, if necessary.
*
* Returns
* 	None.
******************************************************************************/

extern void
HsmBeginRestoreFile(
	bstat_t		*bstatp,
	int		fd,
	int		*hsm_flagp)
{
	int rv;
	XFSattrvalue0_t dmattr;

	/* If it appears to be a DMF-managed file, set the NOMIGR attribute
	 * on it to prevent DMF from touching the file while we are restoring
	 * it. If it turns out to not be a DMF-managed file, we'll need to
	 * remove the attribute when the file is completed.
	 */
	*hsm_flagp = 0;
	if (bstatp->bs_dmevmask && bstatp->bs_xflags & XFS_XFLAG_HASATTR) {
		memset(&dmattr, 0, sizeof(XFSattrvalue0_t));
		dmattr.fsys = FSYS_TYPE_XFS;
		msb_store(dmattr.state, DMF_ST_NOMIGR, sizeof(dmattr.state));

		rv = attr_setf(fd,
			       DMF_ATTR_NAME,
			       (char *)&dmattr,
			       sizeof(dmattr),
			       ATTR_ROOT);
		if (rv == 0)
			*hsm_flagp = 1;
	}
}


/******************************************************************************
* Name
*	HsmRestoreAttribute
*
* Description
**	HsmRestoreAttribute is called when restoring an extended attribute.
*	The hsm_flagp param can be used to keep track of limited state
*	between calls to the HSM restore routines.
*
*	Note that this does not require a filesystem or file context like the
*	HSM calls for xfsdump. This is currently a crude interface to satisfy
*	a specific need. It can be generalized at a later time, if necessary.
*
* Returns
* 	None.
******************************************************************************/

extern void
HsmRestoreAttribute(
	int		flag,		/* ext attr flags */
	char		*namep,		/* pointer to new attribute name */
	int		*hsm_flagp)
{
	/* If the DMF attribute is being restored, then we will not
	 * have to remove the NOMIGR attribute when this file is
	 * being completed.
	 */
	if (flag & ATTR_ROOT && !strcmp(namep, DMF_ATTR_NAME))
		*hsm_flagp = 0;
}


/******************************************************************************
* Name
*	HsmEndRestoreFile
*
* Description
*	HsmEndRestoreFile is called when all data and extended attributes
*	have been restored. The hsm_flagsp param can be used to keep track
*	of limited state between calls to the HSM restore routines.
*
*	Note that this does not require a filesystem or file context like the
*	HSM calls for xfsdump. This is currently a crude interface to satisfy
*	a specific need. It can be generalized at a later time, if necessary.
*
* Returns
* 	None.
******************************************************************************/

extern void
HsmEndRestoreFile(
	char		*path,
	int		fd,
	int		*hsm_flagp)
{
	/* We put a NOMIGR on the file because we thought it was a
	 * DMF-managed file. If it was not, then we need to take
	 * that attribute off now.
	 */
	if (*hsm_flagp) {
		int rv;
		rv = attr_removef(fd, DMF_ATTR_NAME , ATTR_ROOT);
		if (rv) {
			mlog(MLOG_NORMAL | MLOG_WARNING,
			     _("error removing temp DMF attr on %s: %s\n"),
			     path,
			     strerror(errno));
		}
	}
}