xfs_rtalloc.c

linux 内核源代码

/*
 * 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_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_ialloc.h"
#include "xfs_alloc.h"
#include "xfs_bmap.h"
#include "xfs_rtalloc.h"
#include "xfs_fsops.h"
#include "xfs_error.h"
#include "xfs_rw.h"
#include "xfs_inode_item.h"
#include "xfs_trans_space.h"


/*
 * Prototypes for internal functions.
 */


STATIC int xfs_rtallocate_range(xfs_mount_t *, xfs_trans_t *, xfs_rtblock_t,
		xfs_extlen_t, xfs_buf_t **, xfs_fsblock_t *);
STATIC int xfs_rtany_summary(xfs_mount_t *, xfs_trans_t *, int, int,
		xfs_rtblock_t, xfs_buf_t **, xfs_fsblock_t *, int *);
STATIC int xfs_rtcheck_range(xfs_mount_t *, xfs_trans_t *, xfs_rtblock_t,
		xfs_extlen_t, int, xfs_rtblock_t *, int *);
STATIC int xfs_rtfind_back(xfs_mount_t *, xfs_trans_t *, xfs_rtblock_t,
		xfs_rtblock_t, xfs_rtblock_t *);
STATIC int xfs_rtfind_forw(xfs_mount_t *, xfs_trans_t *, xfs_rtblock_t,
		xfs_rtblock_t, xfs_rtblock_t *);
STATIC int xfs_rtget_summary( xfs_mount_t *, xfs_trans_t *, int,
		xfs_rtblock_t, xfs_buf_t **, xfs_fsblock_t *, xfs_suminfo_t *);
STATIC int xfs_rtmodify_range(xfs_mount_t *, xfs_trans_t *, xfs_rtblock_t,
		xfs_extlen_t, int);
STATIC int xfs_rtmodify_summary(xfs_mount_t *, xfs_trans_t *, int,
		xfs_rtblock_t, int, xfs_buf_t **, xfs_fsblock_t *);

/*
 * Internal functions.
 */

/*
 * xfs_lowbit32: get low bit set out of 32-bit argument, -1 if none set.
 */
STATIC int
xfs_lowbit32(
	__uint32_t	v)
{
	if (v)
		return ffs(v) - 1;
	return -1;
}

/*
 * Allocate space to the bitmap or summary file, and zero it, for growfs.
 */
STATIC int				/* error */
xfs_growfs_rt_alloc(
	xfs_mount_t	*mp,		/* file system mount point */
	xfs_extlen_t	oblocks,	/* old count of blocks */
	xfs_extlen_t	nblocks,	/* new count of blocks */
	xfs_ino_t	ino)		/* inode number (bitmap/summary) */
{
	xfs_fileoff_t	bno;		/* block number in file */
	xfs_buf_t	*bp;		/* temporary buffer for zeroing */
	int		cancelflags;	/* flags for xfs_trans_cancel */
	int		committed;	/* transaction committed flag */
	xfs_daddr_t	d;		/* disk block address */
	int		error;		/* error return value */
	xfs_fsblock_t	firstblock;	/* first block allocated in xaction */
	xfs_bmap_free_t	flist;		/* list of freed blocks */
	xfs_fsblock_t	fsbno;		/* filesystem block for bno */
	xfs_inode_t	*ip;		/* pointer to incore inode */
	xfs_bmbt_irec_t	map;		/* block map output */
	int		nmap;		/* number of block maps */
	int		resblks;	/* space reservation */
	xfs_trans_t	*tp;		/* transaction pointer */

	/*
	 * Allocate space to the file, as necessary.
	 */
	while (oblocks < nblocks) {
		tp = xfs_trans_alloc(mp, XFS_TRANS_GROWFSRT_ALLOC);
		resblks = XFS_GROWFSRT_SPACE_RES(mp, nblocks - oblocks);
		cancelflags = 0;
		/*
		 * Reserve space & log for one extent added to the file.
		 */
		if ((error = xfs_trans_reserve(tp, resblks,
				XFS_GROWRTALLOC_LOG_RES(mp), 0,
				XFS_TRANS_PERM_LOG_RES,
				XFS_DEFAULT_PERM_LOG_COUNT)))
			goto error_exit;
		cancelflags = XFS_TRANS_RELEASE_LOG_RES;
		/*
		 * Lock the inode.
		 */
		if ((error = xfs_trans_iget(mp, tp, ino, 0,
						XFS_ILOCK_EXCL, &ip)))
			goto error_exit;
		XFS_BMAP_INIT(&flist, &firstblock);
		/*
		 * Allocate blocks to the bitmap file.
		 */
		nmap = 1;
		cancelflags |= XFS_TRANS_ABORT;
		error = xfs_bmapi(tp, ip, oblocks, nblocks - oblocks,
			XFS_BMAPI_WRITE | XFS_BMAPI_METADATA, &firstblock,
			resblks, &map, &nmap, &flist, NULL);
		if (!error && nmap < 1)
			error = XFS_ERROR(ENOSPC);
		if (error)
			goto error_exit;
		/*
		 * Free any blocks freed up in the transaction, then commit.
		 */
		error = xfs_bmap_finish(&tp, &flist, &committed);
		if (error)
			goto error_exit;
		xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
		/*
		 * Now we need to clear the allocated blocks.
		 * Do this one block per transaction, to keep it simple.
		 */
		cancelflags = 0;
		for (bno = map.br_startoff, fsbno = map.br_startblock;
		     bno < map.br_startoff + map.br_blockcount;
		     bno++, fsbno++) {
			tp = xfs_trans_alloc(mp, XFS_TRANS_GROWFSRT_ZERO);
			/*
			 * Reserve log for one block zeroing.
			 */
			if ((error = xfs_trans_reserve(tp, 0,
					XFS_GROWRTZERO_LOG_RES(mp), 0, 0, 0)))
				goto error_exit;
			/*
			 * Lock the bitmap inode.
			 */
			if ((error = xfs_trans_iget(mp, tp, ino, 0,
							XFS_ILOCK_EXCL, &ip)))
				goto error_exit;
			/*
			 * Get a buffer for the block.
			 */
			d = XFS_FSB_TO_DADDR(mp, fsbno);
			bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
				mp->m_bsize, 0);
			if (bp == NULL) {
				error = XFS_ERROR(EIO);
				goto error_exit;
			}
			memset(XFS_BUF_PTR(bp), 0, mp->m_sb.sb_blocksize);
			xfs_trans_log_buf(tp, bp, 0, mp->m_sb.sb_blocksize - 1);
			/*
			 * Commit the transaction.
			 */
			xfs_trans_commit(tp, 0);
		}
		/*
		 * Go on to the next extent, if any.
		 */
		oblocks = map.br_startoff + map.br_blockcount;
	}
	return 0;
error_exit:
	xfs_trans_cancel(tp, cancelflags);
	return error;
}

/*
 * Attempt to allocate an extent minlen<=len<=maxlen starting from
 * bitmap block bbno.  If we don't get maxlen then use prod to trim
 * the length, if given.  Returns error; returns starting block in *rtblock.
 * The lengths are all in rtextents.
 */
STATIC int				/* error */
xfs_rtallocate_extent_block(
	xfs_mount_t	*mp,		/* file system mount point */
	xfs_trans_t	*tp,		/* transaction pointer */
	xfs_rtblock_t	bbno,		/* bitmap block number */
	xfs_extlen_t	minlen,		/* minimum length to allocate */
	xfs_extlen_t	maxlen,		/* maximum length to allocate */
	xfs_extlen_t	*len,		/* out: actual length allocated */
	xfs_rtblock_t	*nextp,		/* out: next block to try */
	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
	xfs_fsblock_t	*rsb,		/* in/out: summary block number */
	xfs_extlen_t	prod,		/* extent product factor */
	xfs_rtblock_t	*rtblock)	/* out: start block allocated */
{
	xfs_rtblock_t	besti;		/* best rtblock found so far */
	xfs_rtblock_t	bestlen;	/* best length found so far */
	xfs_rtblock_t	end;		/* last rtblock in chunk */
	int		error;		/* error value */
	xfs_rtblock_t	i;		/* current rtblock trying */
	xfs_rtblock_t	next;		/* next rtblock to try */
	int		stat;		/* status from internal calls */

	/*
	 * Loop over all the extents starting in this bitmap block,
	 * looking for one that's long enough.
	 */
	for (i = XFS_BLOCKTOBIT(mp, bbno), besti = -1, bestlen = 0,
		end = XFS_BLOCKTOBIT(mp, bbno + 1) - 1;
	     i <= end;
	     i++) {
		/*
		 * See if there's a free extent of maxlen starting at i.
		 * If it's not so then next will contain the first non-free.
		 */
		error = xfs_rtcheck_range(mp, tp, i, maxlen, 1, &next, &stat);
		if (error) {
			return error;
		}
		if (stat) {
			/*
			 * i for maxlen is all free, allocate and return that.
			 */
			error = xfs_rtallocate_range(mp, tp, i, maxlen, rbpp,
				rsb);
			if (error) {
				return error;
			}
			*len = maxlen;
			*rtblock = i;
			return 0;
		}
		/*
		 * In the case where we have a variable-sized allocation
		 * request, figure out how big this free piece is,
		 * and if it's big enough for the minimum, and the best
		 * so far, remember it.
		 */
		if (minlen < maxlen) {
			xfs_rtblock_t	thislen;	/* this extent size */

			thislen = next - i;
			if (thislen >= minlen && thislen > bestlen) {
				besti = i;
				bestlen = thislen;
			}
		}
		/*
		 * If not done yet, find the start of the next free space.
		 */
		if (next < end) {
			error = xfs_rtfind_forw(mp, tp, next, end, &i);
			if (error) {
				return error;
			}
		} else
			break;
	}
	/*
	 * Searched the whole thing & didn't find a maxlen free extent.
	 */
	if (minlen < maxlen && besti != -1) {
		xfs_extlen_t	p;	/* amount to trim length by */

		/*
		 * If size should be a multiple of prod, make that so.
		 */
		if (prod > 1 && (p = do_mod(bestlen, prod)))
			bestlen -= p;
		/*
		 * Allocate besti for bestlen & return that.
		 */
		error = xfs_rtallocate_range(mp, tp, besti, bestlen, rbpp, rsb);
		if (error) {
			return error;
		}
		*len = bestlen;
		*rtblock = besti;
		return 0;
	}
	/*
	 * Allocation failed.  Set *nextp to the next block to try.
	 */
	*nextp = next;
	*rtblock = NULLRTBLOCK;
	return 0;
}

/*
 * Allocate an extent of length minlen<=len<=maxlen, starting at block
 * bno.  If we don't get maxlen then use prod to trim the length, if given.
 * Returns error; returns starting block in *rtblock.
 * The lengths are all in rtextents.
 */
STATIC int				/* error */
xfs_rtallocate_extent_exact(
	xfs_mount_t	*mp,		/* file system mount point */
	xfs_trans_t	*tp,		/* transaction pointer */
	xfs_rtblock_t	bno,		/* starting block number to allocate */
	xfs_extlen_t	minlen,		/* minimum length to allocate */
	xfs_extlen_t	maxlen,		/* maximum length to allocate */
	xfs_extlen_t	*len,		/* out: actual length allocated */
	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
	xfs_fsblock_t	*rsb,		/* in/out: summary block number */
	xfs_extlen_t	prod,		/* extent product factor */
	xfs_rtblock_t	*rtblock)	/* out: start block allocated */
{
	int		error;		/* error value */
	xfs_extlen_t	i;		/* extent length trimmed due to prod */
	int		isfree;		/* extent is free */
	xfs_rtblock_t	next;		/* next block to try (dummy) */

	ASSERT(minlen % prod == 0 && maxlen % prod == 0);
	/*
	 * Check if the range in question (for maxlen) is free.
	 */
	error = xfs_rtcheck_range(mp, tp, bno, maxlen, 1, &next, &isfree);
	if (error) {
		return error;
	}
	if (isfree) {
		/*
		 * If it is, allocate it and return success.
		 */
		error = xfs_rtallocate_range(mp, tp, bno, maxlen, rbpp, rsb);
		if (error) {
			return error;
		}
		*len = maxlen;
		*rtblock = bno;
		return 0;
	}
	/*
	 * If not, allocate what there is, if it's at least minlen.
	 */
	maxlen = next - bno;
	if (maxlen < minlen) {
		/*
		 * Failed, return failure status.
		 */
		*rtblock = NULLRTBLOCK;
		return 0;
	}
	/*
	 * Trim off tail of extent, if prod is specified.
	 */
	if (prod > 1 && (i = maxlen % prod)) {
		maxlen -= i;
		if (maxlen < minlen) {
			/*
			 * Now we can't do it, return failure status.
			 */
			*rtblock = NULLRTBLOCK;
			return 0;
		}
	}
	/*
	 * Allocate what we can and return it.
	 */
	error = xfs_rtallocate_range(mp, tp, bno, maxlen, rbpp, rsb);
	if (error) {
		return error;
	}
	*len = maxlen;
	*rtblock = bno;
	return 0;
}

/*
 * Allocate an extent of length minlen<=len<=maxlen, starting as near
 * to bno as possible.  If we don't get maxlen then use prod to trim
 * the length, if given.  The lengths are all in rtextents.
 */
STATIC int				/* error */
xfs_rtallocate_extent_near(
	xfs_mount_t	*mp,		/* file system mount point */
	xfs_trans_t	*tp,		/* transaction pointer */
	xfs_rtblock_t	bno,		/* starting block number to allocate */
	xfs_extlen_t	minlen,		/* minimum length to allocate */
	xfs_extlen_t	maxlen,		/* maximum length to allocate */
	xfs_extlen_t	*len,		/* out: actual length allocated */
	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
	xfs_fsblock_t	*rsb,		/* in/out: summary block number */
	xfs_extlen_t	prod,		/* extent product factor */
	xfs_rtblock_t	*rtblock)	/* out: start block allocated */
{
	int		any;		/* any useful extents from summary */
	xfs_rtblock_t	bbno;		/* bitmap block number */
	int		error;		/* error value */
	int		i;		/* bitmap block offset (loop control) */
	int		j;		/* secondary loop control */
	int		log2len;	/* log2 of minlen */
	xfs_rtblock_t	n;		/* next block to try */
	xfs_rtblock_t	r;		/* result block */

	ASSERT(minlen % prod == 0 && maxlen % prod == 0);
	/*
	 * If the block number given is off the end, silently set it to
	 * the last block.
	 */
	if (bno >= mp->m_sb.sb_rextents)
		bno = mp->m_sb.sb_rextents - 1;
	/*
	 * Try the exact allocation first.
	 */
	error = xfs_rtallocate_extent_exact(mp, tp, bno, minlen, maxlen, len,
		rbpp, rsb, prod, &r);
	if (error) {
		return error;
	}
	/*
	 * If the exact allocation worked, return that.
	 */
	if (r != NULLRTBLOCK) {
		*rtblock = r;
		return 0;
	}
	bbno = XFS_BITTOBLOCK(mp, bno);
	i = 0;
	log2len = xfs_highbit32(minlen);
	/*
	 * Loop over all bitmap blocks (bbno + i is current block).
	 */
	for (;;) {
		/*
		 * Get summary information of extents of all useful levels
		 * starting in this bitmap block.
		 */
		error = xfs_rtany_summary(mp, tp, log2len, mp->m_rsumlevels - 1,
			bbno + i, rbpp, rsb, &any);
		if (error) {
			return error;
		}
		/*
		 * If there are any useful extents starting here, try
		 * allocating one.
		 */
		if (any) {
			/*
			 * On the positive side of the starting location.
			 */