linux/fs/xfs/xfs_attr_remote.c

/*
 * Copyright (c) 2000-2005 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 "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_mount.h"
#include "xfs_error.h"
#include "xfs_da_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_alloc.h"
#include "xfs_inode_item.h"
#include "xfs_bmap.h"
#include "xfs_attr.h"
#include "xfs_attr_leaf.h"
#include "xfs_attr_remote.h"
#include "xfs_trans_space.h"
#include "xfs_trace.h"


#define ATTR_RMTVALUE_MAPSIZE	1	/* # of map entries at once */

/*
 * Read the value associated with an attribute from the out-of-line buffer
 * that we stored it in.
 */
int
xfs_attr_rmtval_get(xfs_da_args_t *args)
{
	xfs_bmbt_irec_t map[ATTR_RMTVALUE_MAPSIZE];
	xfs_mount_t *mp;
	xfs_daddr_t dblkno;
	void *dst;
	xfs_buf_t *bp;
	int nmap, error, tmp, valuelen, blkcnt, i;
	xfs_dablk_t lblkno;

	trace_xfs_attr_rmtval_get(args);

	ASSERT(!(args->flags & ATTR_KERNOVAL));

	mp = args->dp->i_mount;
	dst = args->value;
	valuelen = args->valuelen;
	lblkno = args->rmtblkno;
	while (valuelen > 0) {
		nmap = ATTR_RMTVALUE_MAPSIZE;
		error = xfs_bmapi_read(args->dp, (xfs_fileoff_t)lblkno,
				       args->rmtblkcnt, map, &nmap,
				       XFS_BMAPI_ATTRFORK);
		if (error)
			return(error);
		ASSERT(nmap >= 1);

		for (i = 0; (i < nmap) && (valuelen > 0); i++) {
			ASSERT((map[i].br_startblock != DELAYSTARTBLOCK) &&
			       (map[i].br_startblock != HOLESTARTBLOCK));
			dblkno = XFS_FSB_TO_DADDR(mp, map[i].br_startblock);
			blkcnt = XFS_FSB_TO_BB(mp, map[i].br_blockcount);
			error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp,
						   dblkno, blkcnt, 0, &bp, NULL);
			if (error)
				return(error);

			tmp = min_t(int, valuelen, BBTOB(bp->b_length));
			xfs_buf_iomove(bp, 0, tmp, dst, XBRW_READ);
			xfs_buf_relse(bp);
			dst += tmp;
			valuelen -= tmp;

			lblkno += map[i].br_blockcount;
		}
	}
	ASSERT(valuelen == 0);
	return(0);
}

/*
 * Write the value associated with an attribute into the out-of-line buffer
 * that we have defined for it.
 */
int
xfs_attr_rmtval_set(xfs_da_args_t *args)
{
	xfs_mount_t *mp;
	xfs_fileoff_t lfileoff;
	xfs_inode_t *dp;
	xfs_bmbt_irec_t map;
	xfs_daddr_t dblkno;
	void *src;
	xfs_buf_t *bp;
	xfs_dablk_t lblkno;
	int blkcnt, valuelen, nmap, error, tmp, committed;

	trace_xfs_attr_rmtval_set(args);

	dp = args->dp;
	mp = dp->i_mount;
	src = args->value;

	/*
	 * Find a "hole" in the attribute address space large enough for
	 * us to drop the new attribute's value into.
	 */
	blkcnt = XFS_B_TO_FSB(mp, args->valuelen);
	lfileoff = 0;
	error = xfs_bmap_first_unused(args->trans, args->dp, blkcnt, &lfileoff,
						   XFS_ATTR_FORK);
	if (error) {
		return(error);
	}
	args->rmtblkno = lblkno = (xfs_dablk_t)lfileoff;
	args->rmtblkcnt = blkcnt;

	/*
	 * Roll through the "value", allocating blocks on disk as required.
	 */
	while (blkcnt > 0) {
		/*
		 * Allocate a single extent, up to the size of the value.
		 */
		xfs_bmap_init(args->flist, args->firstblock);
		nmap = 1;
		error = xfs_bmapi_write(args->trans, dp, (xfs_fileoff_t)lblkno,
				  blkcnt,
				  XFS_BMAPI_ATTRFORK | XFS_BMAPI_METADATA,
				  args->firstblock, args->total, &map, &nmap,
				  args->flist);
		if (!error) {
			error = xfs_bmap_finish(&args->trans, args->flist,
						&committed);
		}
		if (error) {
			ASSERT(committed);
			args->trans = NULL;
			xfs_bmap_cancel(args->flist);
			return(error);
		}

		/*
		 * bmap_finish() may have committed the last trans and started
		 * a new one.  We need the inode to be in all transactions.
		 */
		if (committed)
			xfs_trans_ijoin(args->trans, dp, 0);

		ASSERT(nmap == 1);
		ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
		       (map.br_startblock != HOLESTARTBLOCK));
		lblkno += map.br_blockcount;
		blkcnt -= map.br_blockcount;

		/*
		 * Start the next trans in the chain.
		 */
		error = xfs_trans_roll(&args->trans, dp);
		if (error)
			return (error);
	}

	/*
	 * Roll through the "value", copying the attribute value to the
	 * already-allocated blocks.  Blocks are written synchronously
	 * so that we can know they are all on disk before we turn off
	 * the INCOMPLETE flag.
	 */
	lblkno = args->rmtblkno;
	valuelen = args->valuelen;
	while (valuelen > 0) {
		int buflen;

		/*
		 * Try to remember where we decided to put the value.
		 */
		xfs_bmap_init(args->flist, args->firstblock);
		nmap = 1;
		error = xfs_bmapi_read(dp, (xfs_fileoff_t)lblkno,
				       args->rmtblkcnt, &map, &nmap,
				       XFS_BMAPI_ATTRFORK);
		if (error)
			return(error);
		ASSERT(nmap == 1);
		ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
		       (map.br_startblock != HOLESTARTBLOCK));

		dblkno = XFS_FSB_TO_DADDR(mp, map.br_startblock),
		blkcnt = XFS_FSB_TO_BB(mp, map.br_blockcount);

		bp = xfs_buf_get(mp->m_ddev_targp, dblkno, blkcnt, 0);
		if (!bp)
			return ENOMEM;

		buflen = BBTOB(bp->b_length);
		tmp = min_t(int, valuelen, buflen);
		xfs_buf_iomove(bp, 0, tmp, src, XBRW_WRITE);
		if (tmp < buflen)
			xfs_buf_zero(bp, tmp, buflen - tmp);

		error = xfs_bwrite(bp);	/* GROT: NOTE: synchronous write */
		xfs_buf_relse(bp);
		if (error)
			return error;
		src += tmp;
		valuelen -= tmp;

		lblkno += map.br_blockcount;
	}
	ASSERT(valuelen == 0);
	return(0);
}

/*
 * Remove the value associated with an attribute by deleting the
 * out-of-line buffer that it is stored on.
 */
int
xfs_attr_rmtval_remove(xfs_da_args_t *args)
{
	xfs_mount_t *mp;
	xfs_bmbt_irec_t map;
	xfs_buf_t *bp;
	xfs_daddr_t dblkno;
	xfs_dablk_t lblkno;
	int valuelen, blkcnt, nmap, error, done, committed;

	trace_xfs_attr_rmtval_remove(args);

	mp = args->dp->i_mount;

	/*
	 * Roll through the "value", invalidating the attribute value's
	 * blocks.
	 */
	lblkno = args->rmtblkno;
	valuelen = args->rmtblkcnt;
	while (valuelen > 0) {
		/*
		 * Try to remember where we decided to put the value.
		 */
		nmap = 1;
		error = xfs_bmapi_read(args->dp, (xfs_fileoff_t)lblkno,
				       args->rmtblkcnt, &map, &nmap,
				       XFS_BMAPI_ATTRFORK);
		if (error)
			return(error);
		ASSERT(nmap == 1);
		ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
		       (map.br_startblock != HOLESTARTBLOCK));

		dblkno = XFS_FSB_TO_DADDR(mp, map.br_startblock),
		blkcnt = XFS_FSB_TO_BB(mp, map.br_blockcount);

		/*
		 * If the "remote" value is in the cache, remove it.
		 */
		bp = xfs_incore(mp->m_ddev_targp, dblkno, blkcnt, XBF_TRYLOCK);
		if (bp) {
			xfs_buf_stale(bp);
			xfs_buf_relse(bp);
			bp = NULL;
		}

		valuelen -= map.br_blockcount;

		lblkno += map.br_blockcount;
	}

	/*
	 * Keep de-allocating extents until the remote-value region is gone.
	 */
	lblkno = args->rmtblkno;
	blkcnt = args->rmtblkcnt;
	done = 0;
	while (!done) {
		xfs_bmap_init(args->flist, args->firstblock);
		error = xfs_bunmapi(args->trans, args->dp, lblkno, blkcnt,
				    XFS_BMAPI_ATTRFORK | XFS_BMAPI_METADATA,
				    1, args->firstblock, args->flist,
				    &done);
		if (!error) {
			error = xfs_bmap_finish(&args->trans, args->flist,
						&committed);
		}
		if (error) {
			ASSERT(committed);
			args->trans = NULL;
			xfs_bmap_cancel(args->flist);
			return(error);
		}

		/*
		 * bmap_finish() may have committed the last trans and started
		 * a new one.  We need the inode to be in all transactions.
		 */
		if (committed)
			xfs_trans_ijoin(args->trans, args->dp, 0);

		/*
		 * Close out trans and start the next one in the chain.
		 */
		error = xfs_trans_roll(&args->trans, args->dp);
		if (error)
			return (error);
	}
	return(0);
}