/*
 * Copyright (c) 2000-2002 Silicon Graphics, Inc.  All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 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.
 *
 * Further, this software is distributed without any warranty that it is
 * free of the rightful claim of any third person regarding infringement
 * or the like.  Any license provided herein, whether implied or
 * otherwise, applies only to this software file.  Patent licenses, if
 * any, provided herein do not apply to combinations of this program with
 * other software, or any other product whatsoever.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write the Free Software Foundation, Inc., 59
 * Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
 * Mountain View, CA  94043, or:
 *
 * http://www.sgi.com
 *
 * For further information regarding this notice, see:
 *
 * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
 */

#include "xfs.h"
#include "xfs_macros.h"
#include "xfs_types.h"
#include "xfs_inum.h"
#include "xfs_log.h"
#include "xfs_ag.h"
#include "xfs_sb.h"
#include "xfs_trans.h"
#include "xfs_dir.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_error.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc.h"
#include "xfs_attr_sf.h"
#include "xfs_dir_sf.h"
#include "xfs_dir2_sf.h"
#include "xfs_dinode.h"
#include "xfs_imap.h"
#include "xfs_inode_item.h"
#include "xfs_inode.h"
#include "xfs_ialloc_btree.h"
#include "xfs_ialloc.h"
#include "xfs_error.h"
#include "xfs_log_priv.h"
#include "xfs_buf_item.h"
#include "xfs_alloc_btree.h"
#include "xfs_log_recover.h"
#include "xfs_extfree_item.h"
#include "xfs_trans_priv.h"
#include "xfs_bit.h"
#include "xfs_quota.h"
#include "xfs_rw.h"

STATIC int	xlog_find_zeroed(struct log *log, xfs_daddr_t *blk_no);

STATIC int	xlog_clear_stale_blocks(xlog_t	*log, xfs_lsn_t tail_lsn);
STATIC void	xlog_recover_insert_item_backq(xlog_recover_item_t **q,
					       xlog_recover_item_t *item);

#if defined(DEBUG)
STATIC void	xlog_recover_check_summary(xlog_t *log);
STATIC void	xlog_recover_check_ail(xfs_mount_t *mp, xfs_log_item_t *lip,
				       int gen);
#else
#define	xlog_recover_check_summary(log)
#define	xlog_recover_check_ail(mp, lip, gen)
#endif /* DEBUG */


xfs_buf_t *
xlog_get_bp(int num_bblks, xfs_mount_t *mp)
{
	xfs_buf_t   *bp;

	ASSERT(num_bblks > 0);

	bp = XFS_ngetrbuf(BBTOB(num_bblks),mp);
	return bp;
}	/* xlog_get_bp */


void
xlog_put_bp(xfs_buf_t *bp)
{
	XFS_nfreerbuf(bp);
}	/* xlog_put_bp */


/*
 * nbblks should be uint, but oh well.  Just want to catch that 32-bit length.
 */
int
xlog_bread(xlog_t	*log,
	   xfs_daddr_t	blk_no,
	   int		nbblks,
	   xfs_buf_t	*bp)
{
	int error;

	ASSERT(log);
	ASSERT(nbblks > 0);
	ASSERT(BBTOB(nbblks) <= XFS_BUF_SIZE(bp));
	ASSERT(bp);

	XFS_BUF_SET_ADDR(bp, log->l_logBBstart + blk_no);
	XFS_BUF_READ(bp);
	XFS_BUF_BUSY(bp);
	XFS_BUF_SET_COUNT(bp, BBTOB(nbblks));
	XFS_BUF_SET_TARGET(bp, log->l_mp->m_logdev_targp);

	xfsbdstrat(log->l_mp, bp);
	if ((error = xfs_iowait(bp))) {
		xfs_ioerror_alert("xlog_bread", log->l_mp,
				  bp, XFS_BUF_ADDR(bp));
		return (error);
	}
	return error;
}	/* xlog_bread */


/*
 * Write out the buffer at the given block for the given number of blocks.
 * The buffer is kept locked across the write and is returned locked.
 * This can only be used for synchronous log writes.
 */
int
xlog_bwrite(
	xlog_t	*log,
	int	blk_no,
	int	nbblks,
	xfs_buf_t	*bp)
{
	int	error;

	ASSERT(nbblks > 0);
	ASSERT(BBTOB(nbblks) <= XFS_BUF_SIZE(bp));

	XFS_BUF_SET_ADDR(bp, log->l_logBBstart + blk_no);
	XFS_BUF_ZEROFLAGS(bp);
	XFS_BUF_BUSY(bp);
	XFS_BUF_HOLD(bp);
	XFS_BUF_PSEMA(bp, PRIBIO);
	XFS_BUF_SET_COUNT(bp, BBTOB(nbblks));
	XFS_BUF_SET_TARGET(bp, log->l_mp->m_logdev_targp);

	if ((error = xfs_bwrite(log->l_mp, bp)))
		xfs_ioerror_alert("xlog_bwrite", log->l_mp,
				  bp, XFS_BUF_ADDR(bp));

	return (error);
}	/* xlog_bwrite */

#ifdef DEBUG
/*
 * check log record header for recovery
 */
static void
xlog_header_check_dump(xfs_mount_t *mp, xlog_rec_header_t *head)
{
    int b;

    printk("%s:  SB : uuid = ", __FUNCTION__);
    for (b=0;b<16;b++) printk("%02x",((unsigned char *)&mp->m_sb.sb_uuid)[b]);
    printk(", fmt = %d\n",XLOG_FMT);
    printk("    log : uuid = ");
    for (b=0;b<16;b++) printk("%02x",((unsigned char *)&head->h_fs_uuid)[b]);
    printk(", fmt = %d\n", INT_GET(head->h_fmt, ARCH_CONVERT));
}
#endif

/*
 * check log record header for recovery
 */

STATIC int
xlog_header_check_recover(xfs_mount_t *mp, xlog_rec_header_t *head)
{
    ASSERT(INT_GET(head->h_magicno, ARCH_CONVERT) == XLOG_HEADER_MAGIC_NUM);

    /*
     * IRIX doesn't write the h_fmt field and leaves it zeroed
     * (XLOG_FMT_UNKNOWN). This stops us from trying to recover
     * a dirty log created in IRIX.
     */

    if (unlikely(INT_GET(head->h_fmt, ARCH_CONVERT) != XLOG_FMT)) {
	xlog_warn("XFS: dirty log written in incompatible format - can't recover");
#ifdef DEBUG
	xlog_header_check_dump(mp, head);
#endif
	XFS_ERROR_REPORT("xlog_header_check_recover(1)",
			 XFS_ERRLEVEL_HIGH, mp);
	return XFS_ERROR(EFSCORRUPTED);
    } else if (unlikely(!uuid_equal(&mp->m_sb.sb_uuid, &head->h_fs_uuid))) {
	xlog_warn("XFS: dirty log entry has mismatched uuid - can't recover");
#ifdef DEBUG
	xlog_header_check_dump(mp, head);
#endif
	XFS_ERROR_REPORT("xlog_header_check_recover(2)",
			 XFS_ERRLEVEL_HIGH, mp);
	return XFS_ERROR(EFSCORRUPTED);
    }

    return 0;
}

/*
 * read the head block of the log and check the header
 */

STATIC int
xlog_header_check_mount(xfs_mount_t *mp, xlog_rec_header_t *head)
{
    ASSERT(INT_GET(head->h_magicno, ARCH_CONVERT) == XLOG_HEADER_MAGIC_NUM);

    if (uuid_is_nil(&head->h_fs_uuid)) {

	/*
	 * IRIX doesn't write the h_fs_uuid or h_fmt fields. If
	 * h_fs_uuid is nil, we assume this log was last mounted
	 * by IRIX and continue.
	 */

	xlog_warn("XFS: nil uuid in log - IRIX style log");

    } else if (unlikely(!uuid_equal(&mp->m_sb.sb_uuid, &head->h_fs_uuid))) {
	xlog_warn("XFS: log has mismatched uuid - can't recover");
#ifdef DEBUG
	xlog_header_check_dump(mp, head);
#endif
	XFS_ERROR_REPORT("xlog_header_check_mount",
			 XFS_ERRLEVEL_HIGH, mp);
	return XFS_ERROR(EFSCORRUPTED);
    }

    return 0;
}

STATIC void
xlog_recover_iodone(
	struct xfs_buf	*bp)
{
	xfs_mount_t	*mp;
	ASSERT(XFS_BUF_FSPRIVATE(bp, void *));

	if (XFS_BUF_GETERROR(bp)) {
		/*
		 * We're not going to bother about retrying
		 * this during recovery. One strike!
		 */
		mp = XFS_BUF_FSPRIVATE(bp, xfs_mount_t *);
		xfs_ioerror_alert("xlog_recover_iodone",
				  mp, bp, XFS_BUF_ADDR(bp));
		xfs_force_shutdown(mp, XFS_METADATA_IO_ERROR);
	}
	XFS_BUF_SET_FSPRIVATE(bp, NULL);
	XFS_BUF_CLR_IODONE_FUNC(bp);
	xfs_biodone(bp);
}

/*
 * This routine finds (to an approximation) the first block in the physical
 * log which contains the given cycle.  It uses a binary search algorithm.
 * Note that the algorithm can not be perfect because the disk will not
 * necessarily be perfect.
 */
int
xlog_find_cycle_start(xlog_t		*log,
		      xfs_buf_t		*bp,
		      xfs_daddr_t	first_blk,
		      xfs_daddr_t	*last_blk,
		      uint		cycle)
{
	xfs_daddr_t	mid_blk;
	uint		mid_cycle;
	int		error;

	mid_blk = BLK_AVG(first_blk, *last_blk);
	while (mid_blk != first_blk && mid_blk != *last_blk) {
		if ((error = xlog_bread(log, mid_blk, 1, bp)))
			return error;
		mid_cycle = GET_CYCLE(XFS_BUF_PTR(bp), ARCH_CONVERT);
		if (mid_cycle == cycle) {
			*last_blk = mid_blk;
			/* last_half_cycle == mid_cycle */
		} else {
			first_blk = mid_blk;
			/* first_half_cycle == mid_cycle */
		}
		mid_blk = BLK_AVG(first_blk, *last_blk);
	}
	ASSERT((mid_blk == first_blk && mid_blk+1 == *last_blk) ||
	       (mid_blk == *last_blk && mid_blk-1 == first_blk));

	return 0;
}	/* xlog_find_cycle_start */


/*
 * Check that the range of blocks does not contain the cycle number
 * given.  The scan needs to occur from front to back and the ptr into the
 * region must be updated since a later routine will need to perform another
 * test.  If the region is completely good, we end up returning the same
 * last block number.
 *
 * Set blkno to -1 if we encounter no errors.  This is an invalid block number
 * since we don't ever expect logs to get this large.
 */

STATIC int
xlog_find_verify_cycle( xlog_t		*log,
			xfs_daddr_t	start_blk,
			int		nbblks,
			uint		stop_on_cycle_no,
			xfs_daddr_t	*new_blk)
{
	xfs_daddr_t		i, j;
	uint			cycle;
	xfs_buf_t		*bp;
	char                    *buf        = NULL;
	int			error       = 0;
	xfs_daddr_t		bufblks;

	bufblks = 1 << ffs(nbblks);

	while (!(bp = xlog_get_bp(bufblks, log->l_mp))) {
		/* can't get enough memory to do everything in one big buffer */
		bufblks >>= 1;
		if (!bufblks)
			return ENOMEM;
	}

	for (i = start_blk; i < start_blk + nbblks; i += bufblks) {
		int	bcount;

		bcount = min(bufblks, (start_blk + nbblks - i));

		if ((error = xlog_bread(log, i, bcount, bp)))
			goto out;

		buf = XFS_BUF_PTR(bp);
		for (j = 0; j < bcount; j++) {
			cycle = GET_CYCLE(buf, ARCH_CONVERT);
			if (cycle == stop_on_cycle_no) {
				*new_blk = i+j;
				goto out;
			}

			buf += BBSIZE;
		}
	}

	*new_blk = -1;

out:
	xlog_put_bp(bp);

	return error;
}	/* xlog_find_verify_cycle */


/*
 * Potentially backup over partial log record write.
 *
 * In the typical case, last_blk is the number of the block directly after
 * a good log record.  Therefore, we subtract one to get the block number
 * of the last block in the given buffer.  extra_bblks contains the number
 * of blocks we would have read on a previous read.  This happens when the
 * last log record is split over the end of the physical log.
 *
 * extra_bblks is the number of blocks potentially verified on a previous
 * call to this routine.
 */

STATIC int
xlog_find_verify_log_record(xlog_t	*log,
			    xfs_daddr_t	start_blk,
			    xfs_daddr_t	*last_blk,
			    int		extra_bblks)
{
    xfs_daddr_t         i;
    xfs_buf_t		*bp;
    char                *buf        = NULL;
    xlog_rec_header_t	*head       = NULL;
    int			error       = 0;
    int                 smallmem    = 0;
    int                 num_blks    = *last_blk - start_blk;
    int			xhdrs;

    ASSERT(start_blk != 0 || *last_blk != start_blk);

    if (!(bp = xlog_get_bp(num_blks, log->l_mp))) {
	if (!(bp = xlog_get_bp(1, log->l_mp)))
	    return ENOMEM;
	smallmem = 1;
	buf = XFS_BUF_PTR(bp);
    } else {
	if ((error = xlog_bread(log, start_blk, num_blks, bp)))
	    goto out;
	buf = XFS_BUF_PTR(bp) + ((num_blks - 1) << BBSHIFT);
    }

    for (i = (*last_blk) - 1; i >= 0; i--) {
	if (i < start_blk) {
	    /* legal log record not found */
	    xlog_warn("XFS: Log inconsistent (didn't find previous header)");
	    ASSERT(0);
	    error = XFS_ERROR(EIO);
	    goto out;
	}

	if (smallmem && (error = xlog_bread(log, i, 1, bp)))
	    goto out;
	head = (xlog_rec_header_t*)buf;

	if (INT_GET(head->h_magicno, ARCH_CONVERT) == XLOG_HEADER_MAGIC_NUM)
	    break;

	if (!smallmem)
	    buf -= BBSIZE;
    }

    /*
     * We hit the beginning of the physical log & still no header.  Return
     * to caller.  If caller can handle a return of -1, then this routine
     * will be called again for the end of the physical log.
     */
    if (i == -1) {
	error = -1;
	goto out;
    }

    /* we have the final block of the good log (the first block
     * of the log record _before_ the head. So we check the uuid.
     */

    if ((error = xlog_header_check_mount(log->l_mp, head)))
	goto out;

    /*
     * We may have found a log record header before we expected one.
     * last_blk will be the 1st block # with a given cycle #.  We may end
     * up reading an entire log record.  In this case, we don't want to
     * reset last_blk.  Only when last_blk points in the middle of a log
     * record do we update last_blk.
     */
    if (XFS_SB_VERSION_HASLOGV2(&log->l_mp->m_sb)) {
	uint	h_size = INT_GET(head->h_size, ARCH_CONVERT);

	xhdrs = h_size / XLOG_HEADER_CYCLE_SIZE;
	if (h_size % XLOG_HEADER_CYCLE_SIZE)
		xhdrs++;
    } else {
	xhdrs = 1;
    }

    if (*last_blk - i + extra_bblks
		!= BTOBB(INT_GET(head->h_len, ARCH_CONVERT))+xhdrs)
	    *last_blk = i;

out:
    xlog_put_bp(bp);

    return error;
}	/* xlog_find_verify_log_record */

/*
 * Head is defined to be the point of the log where the next log write
 * write could go.  This means that incomplete LR writes at the end are
 * eliminated when calculating the head.  We aren't guaranteed that previous
 * LR have complete transactions.  We only know that a cycle number of
 * current cycle number -1 won't be present in the log if we start writing
 * from our current block number.
 *
 * last_blk contains the block number of the first block with a given
 * cycle number.
 *
 * Also called from xfs_log_print.c
 *
 * Return: zero if normal, non-zero if error.
 */
int
xlog_find_head(xlog_t  *log,
	       xfs_daddr_t *return_head_blk)
{
    xfs_buf_t   *bp;
    xfs_daddr_t new_blk, first_blk, start_blk, last_blk, head_blk;
    int     num_scan_bblks;
    uint    first_half_cycle, last_half_cycle;
    uint    stop_on_cycle;
    int     error, log_bbnum = log->l_logBBsize;

    /* Is the end of the log device zeroed? */
    if ((error = xlog_find_zeroed(log, &first_blk)) == -1) {
	*return_head_blk = first_blk;

	/* is the whole lot zeroed? */
	if (!first_blk) {
	    /* Linux XFS shouldn't generate totally zeroed logs -
	     * mkfs etc write a dummy unmount record to a fresh
	     * log so we can store the uuid in there
	     */
	    xlog_warn("XFS: totally zeroed log");
	}

	return 0;
    } else if (error) {
	xlog_warn("XFS: empty log check failed");
	return error;
    }

    first_blk = 0;				/* get cycle # of 1st block */
    bp = xlog_get_bp(1,log->l_mp);
    if (!bp)
	return ENOMEM;
    if ((error = xlog_bread(log, 0, 1, bp)))
	goto bp_err;
    first_half_cycle = GET_CYCLE(XFS_BUF_PTR(bp), ARCH_CONVERT);

    last_blk = head_blk = log_bbnum-1;		/* get cycle # of last block */
    if ((error = xlog_bread(log, last_blk, 1, bp)))
	goto bp_err;
    last_half_cycle = GET_CYCLE(XFS_BUF_PTR(bp), ARCH_CONVERT);
    ASSERT(last_half_cycle != 0);

    /*
     * If the 1st half cycle number is equal to the last half cycle number,
     * then the entire log is stamped with the same cycle number.  In this
     * case, head_blk can't be set to zero (which makes sense).  The below
     * math doesn't work out properly with head_blk equal to zero.  Instead,
     * we set it to log_bbnum which is an illegal block number, but this
     * value makes the math correct.  If head_blk doesn't changed through
     * all the tests below, *head_blk is set to zero at the very end rather
     * than log_bbnum.  In a sense, log_bbnum and zero are the same block
     * in a circular file.
     */
    if (first_half_cycle == last_half_cycle) {
	/*
	 * In this case we believe that the entire log should have cycle
	 * number last_half_cycle.  We need to scan backwards from the
	 * end verifying that there are no holes still containing
	 * last_half_cycle - 1.  If we find such a hole, then the start
	 * of that hole will be the new head.  The simple case looks like
	 *        x | x ... | x - 1 | x
	 * Another case that fits this picture would be
	 *        x | x + 1 | x ... | x
	 * In this case the head really is somwhere at the end of the
	 * log, as one of the latest writes at the beginning was incomplete.
	 * One more case is
	 *        x | x + 1 | x ... | x - 1 | x
	 * This is really the combination of the above two cases, and the
	 * head has to end up at the start of the x-1 hole at the end of
	 * the log.
	 *
	 * In the 256k log case, we will read from the beginning to the
	 * end of the log and search for cycle numbers equal to x-1.  We
	 * don't worry about the x+1 blocks that we encounter, because
	 * we know that they cannot be the head since the log started with
	 * x.
	 */
	head_blk = log_bbnum;
	stop_on_cycle = last_half_cycle - 1;
    } else {
	/*
	 * In this case we want to find the first block with cycle number
	 * matching last_half_cycle.  We expect the log to be some
	 * variation on
	 *        x + 1 ... | x ...
	 * The first block with cycle number x (last_half_cycle) will be
	 * where the new head belongs.  First we do a binary search for
	 * the first occurrence of last_half_cycle.  The binary search
	 * may not be totally accurate, so then we scan back from there
	 * looking for occurrences of last_half_cycle before us.  If
	 * that backwards scan wraps around the beginning of the log,
	 * then we look for occurrences of last_half_cycle - 1 at the
	 * end of the log.  The cases we're looking for look like
	 *        x + 1 ... | x | x + 1 | x ...
	 *                               ^ binary search stopped here
	 * or
	 *        x + 1 ... | x ... | x - 1 | x
	 *        <---------> less than scan distance
	 */
	stop_on_cycle = last_half_cycle;
	if ((error = xlog_find_cycle_start(log, bp, first_blk,
					  &head_blk, last_half_cycle)))
	    goto bp_err;
    }

    /*
     * Now validate the answer.  Scan back some number of maximum possible
     * blocks and make sure each one has the expected cycle number.  The
     * maximum is determined by the total possible amount of buffering
     * in the in-core log.  The following number can be made tighter if
     * we actually look at the block size of the filesystem.
     */
    num_scan_bblks = XLOG_TOTAL_REC_SHIFT(log);
    if (head_blk >= num_scan_bblks) {
	/*
	 * We are guaranteed that the entire check can be performed
	 * in one buffer.
	 */
	start_blk = head_blk - num_scan_bblks;
	if ((error = xlog_find_verify_cycle(log, start_blk, num_scan_bblks,
					 stop_on_cycle, &new_blk)))
	    goto bp_err;
	if (new_blk != -1)
	    head_blk = new_blk;
    } else {			/* need to read 2 parts of log */
	/*
	 * We are going to scan backwards in the log in two parts.  First
	 * we scan the physical end of the log.  In this part of the log,
	 * we are looking for blocks with cycle number last_half_cycle - 1.
	 * If we find one, then we know that the log starts there, as we've
	 * found a hole that didn't get written in going around the end
	 * of the physical log.  The simple case for this is
	 *        x + 1 ... | x ... | x - 1 | x
	 *        <---------> less than scan distance
	 * If all of the blocks at the end of the log have cycle number
	 * last_half_cycle, then we check the blocks at the start of the
	 * log looking for occurrences of last_half_cycle.  If we find one,
	 * then our current estimate for the location of the first
	 * occurrence of last_half_cycle is wrong and we move back to the
	 * hole we've found.  This case looks like
	 *        x + 1 ... | x | x + 1 | x ...
	 *                               ^ binary search stopped here
	 * Another case we need to handle that only occurs in 256k logs is
	 *        x + 1 ... | x ... | x+1 | x ...
	 *                   ^ binary search stops here
	 * In a 256k log, the scan at the end of the log will see the x+1
	 * blocks.  We need to skip past those since that is certainly not
	 * the head of the log.  By searching for last_half_cycle-1 we
	 * accomplish that.
	 */
	start_blk = log_bbnum - num_scan_bblks + head_blk;
	ASSERT(head_blk <= INT_MAX && (xfs_daddr_t) num_scan_bblks-head_blk >= 0);
	if ((error = xlog_find_verify_cycle(log, start_blk,
			num_scan_bblks-(int)head_blk, (stop_on_cycle - 1),
			&new_blk)))
		goto bp_err;
	if (new_blk != -1) {
	    head_blk = new_blk;
	    goto bad_blk;
	}

	/*
	 * Scan beginning of log now.  The last part of the physical log
	 * is good.  This scan needs to verify that it doesn't find the
	 * last_half_cycle.
	 */
	start_blk = 0;
	ASSERT(head_blk <= INT_MAX);
	if ((error = xlog_find_verify_cycle(log, start_blk, (int) head_blk,
					 stop_on_cycle, &new_blk)))
	    goto bp_err;
	if (new_blk != -1)
	    head_blk = new_blk;
    }

bad_blk:
    /*
     * Now we need to make sure head_blk is not pointing to a block in
     * the middle of a log record.
     */
    num_scan_bblks = BTOBB(XLOG_MAX_RECORD_BSIZE);
    if (head_blk >= num_scan_bblks) {
	start_blk = head_blk - num_scan_bblks;  /* don't read head_blk */

	/* start ptr at last block ptr before head_blk */
	if ((error = xlog_find_verify_log_record(log,
						 start_blk,
						 &head_blk,
						 0)) == -1) {
	    error = XFS_ERROR(EIO);
	    goto bp_err;
	} else if (error)
	    goto bp_err;
    } else {
	start_blk = 0;
	ASSERT(head_blk <= INT_MAX);
	if ((error = xlog_find_verify_log_record(log,
						 start_blk,
						 &head_blk,
						 0)) == -1) {
	    /* We hit the beginning of the log during our search */
	    start_blk = log_bbnum - num_scan_bblks + head_blk;
	    new_blk = log_bbnum;
	    ASSERT(start_blk <= INT_MAX && (xfs_daddr_t) log_bbnum-start_blk >= 0);
	    ASSERT(head_blk <= INT_MAX);
	    if ((error = xlog_find_verify_log_record(log,
						     start_blk,
						     &new_blk,
						     (int)head_blk)) == -1) {
		error = XFS_ERROR(EIO);
		goto bp_err;
	    } else if (error)
		goto bp_err;
	    if (new_blk != log_bbnum)
		head_blk = new_blk;
	} else if (error)
	    goto bp_err;
    }

    xlog_put_bp(bp);
    if (head_blk == log_bbnum)
	    *return_head_blk = 0;
    else
	    *return_head_blk = head_blk;
    /*
     * When returning here, we have a good block number.  Bad block
     * means that during a previous crash, we didn't have a clean break
     * from cycle number N to cycle number N-1.  In this case, we need
     * to find the first block with cycle number N-1.
     */
    return 0;

bp_err:
	xlog_put_bp(bp);

	if (error)
	    xlog_warn("XFS: failed to find log head");

	return error;
}	/* xlog_find_head */

/*
 * Find the sync block number or the tail of the log.
 *
 * This will be the block number of the last record to have its
 * associated buffers synced to disk.  Every log record header has
 * a sync lsn embedded in it.  LSNs hold block numbers, so it is easy
 * to get a sync block number.  The only concern is to figure out which
 * log record header to believe.
 *
 * The following algorithm uses the log record header with the largest
 * lsn.  The entire log record does not need to be valid.  We only care
 * that the header is valid.
 *
 * We could speed up search by using current head_blk buffer, but it is not
 * available.
 */
int
xlog_find_tail(xlog_t		*log,
	       xfs_daddr_t	*head_blk,
	       xfs_daddr_t	*tail_blk,
	       int		readonly)
{
	xlog_rec_header_t	*rhead;
	xlog_op_header_t	*op_head;
	xfs_buf_t		*bp;
	int			error, i, found;
	xfs_daddr_t		umount_data_blk;
	xfs_daddr_t		after_umount_blk;
	xfs_lsn_t		tail_lsn;
	int			hblks;

	found = 0;

	/*
	 * Find previous log record
	 */
	if ((error = xlog_find_head(log, head_blk)))
		return error;

	bp = xlog_get_bp(1,log->l_mp);
	if (!bp)
		return ENOMEM;
	if (*head_blk == 0) {				/* special case */
		if ((error = xlog_bread(log, 0, 1, bp)))
			goto bread_err;
		if (GET_CYCLE(XFS_BUF_PTR(bp), ARCH_CONVERT) == 0) {
			*tail_blk = 0;
			/* leave all other log inited values alone */
			goto exit;
		}
	}

	/*
	 * Search backwards looking for log record header block
	 */
	ASSERT(*head_blk < INT_MAX);
	for (i = (int)(*head_blk) - 1; i >= 0; i--) {
		if ((error = xlog_bread(log, i, 1, bp)))
			goto bread_err;
		if (XLOG_HEADER_MAGIC_NUM ==
		    INT_GET(*(uint *)(XFS_BUF_PTR(bp)), ARCH_CONVERT)) {
			found = 1;
			break;
		}
	}
	/*
	 * If we haven't found the log record header block, start looking
	 * again from the end of the physical log.  XXXmiken: There should be
	 * a check here to make sure we didn't search more than N blocks in
	 * the previous code.
	 */
	if (!found) {
		for (i = log->l_logBBsize - 1; i >= (int)(*head_blk); i--) {
			if ((error = xlog_bread(log, i, 1, bp)))
				goto bread_err;
			if (XLOG_HEADER_MAGIC_NUM ==
			    INT_GET(*(uint*)(XFS_BUF_PTR(bp)), ARCH_CONVERT)) {
				found = 2;
				break;
			}
		}
	}
	if (!found) {
		xlog_warn("XFS: xlog_find_tail: couldn't find sync record");
		ASSERT(0);
		return XFS_ERROR(EIO);
	}

	/* find blk_no of tail of log */
	rhead = (xlog_rec_header_t *)XFS_BUF_PTR(bp);
	*tail_blk = BLOCK_LSN(rhead->h_tail_lsn, ARCH_CONVERT);

	/*
	 * Reset log values according to the state of the log when we
	 * crashed.  In the case where head_blk == 0, we bump curr_cycle
	 * one because the next write starts a new cycle rather than
	 * continuing the cycle of the last good log record.  At this
	 * point we have guaranteed that all partial log records have been
	 * accounted for.  Therefore, we know that the last good log record
	 * written was complete and ended exactly on the end boundary
	 * of the physical log.
	 */
	log->l_prev_block = i;
	log->l_curr_block = (int)*head_blk;
	log->l_curr_cycle = INT_GET(rhead->h_cycle, ARCH_CONVERT);
	if (found == 2)
		log->l_curr_cycle++;
	log->l_tail_lsn = INT_GET(rhead->h_tail_lsn, ARCH_CONVERT);
	log->l_last_sync_lsn = INT_GET(rhead->h_lsn, ARCH_CONVERT);
	log->l_grant_reserve_cycle = log->l_curr_cycle;
	log->l_grant_reserve_bytes = BBTOB(log->l_curr_block);
	log->l_grant_write_cycle = log->l_curr_cycle;
	log->l_grant_write_bytes = BBTOB(log->l_curr_block);

	/*
	 * Look for unmount record.  If we find it, then we know there
	 * was a clean unmount.  Since 'i' could be the last block in
	 * the physical log, we convert to a log block before comparing
	 * to the head_blk.
	 *
	 * Save the current tail lsn to use to pass to
	 * xlog_clear_stale_blocks() below.  We won't want to clear the
	 * unmount record if there is one, so we pass the lsn of the
	 * unmount record rather than the block after it.
	 */
	if (XFS_SB_VERSION_HASLOGV2(&log->l_mp->m_sb)) {
		int	h_size = INT_GET(rhead->h_size, ARCH_CONVERT);
		int	h_version = INT_GET(rhead->h_version, ARCH_CONVERT);

		if ((h_version & XLOG_VERSION_2) &&
		    (h_size > XLOG_HEADER_CYCLE_SIZE)) {
			hblks = h_size / XLOG_HEADER_CYCLE_SIZE;
			if (h_size % XLOG_HEADER_CYCLE_SIZE)
				hblks++;
		} else {
			hblks = 1;
		}
	} else {
		hblks = 1;
	}
	after_umount_blk = (i + hblks + (int)
		BTOBB(INT_GET(rhead->h_len, ARCH_CONVERT))) % log->l_logBBsize;
	tail_lsn = log->l_tail_lsn;
	if (*head_blk == after_umount_blk &&
	    INT_GET(rhead->h_num_logops, ARCH_CONVERT) == 1) {
		umount_data_blk = (i + hblks) % log->l_logBBsize;
		if ((error = xlog_bread(log, umount_data_blk, 1, bp))) {
			goto bread_err;
		}
		op_head = (xlog_op_header_t *)XFS_BUF_PTR(bp);
		if (op_head->oh_flags & XLOG_UNMOUNT_TRANS) {
			/*
			 * Set tail and last sync so that newly written
			 * log records will point recovery to after the
			 * current unmount record.
			 */
			ASSIGN_ANY_LSN(log->l_tail_lsn, log->l_curr_cycle,
					after_umount_blk, ARCH_NOCONVERT);
			ASSIGN_ANY_LSN(log->l_last_sync_lsn, log->l_curr_cycle,
					after_umount_blk, ARCH_NOCONVERT);
			*tail_blk = after_umount_blk;
		}
	}

#ifdef __KERNEL__
	/*
	 * Make sure that there are no blocks in front of the head
	 * with the same cycle number as the head.  This can happen
	 * because we allow multiple outstanding log writes concurrently,
	 * and the later writes might make it out before earlier ones.
	 *
	 * We use the lsn from before modifying it so that we'll never
	 * overwrite the unmount record after a clean unmount.
	 *
	 * Do this only if we are going to recover the filesystem
	 *
	 * NOTE: This used to say "if (!readonly)"
	 * However on Linux, we can & do recover a read-only filesystem.
	 * We only skip recovery if NORECOVERY is specified on mount,
	 * in which case we would not be here.
	 *
	 * But... if the -device- itself is readonly, just skip this.
	 * We can't recover this device anyway, so it won't matter.
	 */

	if (!bdev_read_only(log->l_mp->m_logdev_targp->pbr_bdev)) {
		error = xlog_clear_stale_blocks(log, tail_lsn);
	}
#endif

bread_err:
exit:
	xlog_put_bp(bp);

	if (error)
		xlog_warn("XFS: failed to locate log tail");

	return error;
}	/* xlog_find_tail */


/*
 * Is the log zeroed at all?
 *
 * The last binary search should be changed to perform an X block read
 * once X becomes small enough.  You can then search linearly through
 * the X blocks.  This will cut down on the number of reads we need to do.
 *
 * If the log is partially zeroed, this routine will pass back the blkno
 * of the first block with cycle number 0.  It won't have a complete LR
 * preceding it.
 *
 * Return:
 *	0  => the log is completely written to
 *	-1 => use *blk_no as the first block of the log
 *	>0 => error has occurred
 */
int
xlog_find_zeroed(struct log	*log,
		 xfs_daddr_t	*blk_no)
{
	xfs_buf_t	*bp;
	uint	        first_cycle, last_cycle;
	xfs_daddr_t	new_blk, last_blk, start_blk;
	xfs_daddr_t     num_scan_bblks;
	int	        error, log_bbnum = log->l_logBBsize;

	/* check totally zeroed log */
	bp = xlog_get_bp(1,log->l_mp);
	if (!bp)
		return ENOMEM;
	if ((error = xlog_bread(log, 0, 1, bp)))
		goto bp_err;
	first_cycle = GET_CYCLE(XFS_BUF_PTR(bp), ARCH_CONVERT);
	if (first_cycle == 0) {		/* completely zeroed log */
		*blk_no = 0;
		xlog_put_bp(bp);
		return -1;
	}

	/* check partially zeroed log */
	if ((error = xlog_bread(log, log_bbnum-1, 1, bp)))
		goto bp_err;
	last_cycle = GET_CYCLE(XFS_BUF_PTR(bp), ARCH_CONVERT);
	if (last_cycle != 0) {		/* log completely written to */
		xlog_put_bp(bp);
		return 0;
	} else if (first_cycle != 1) {
		/*
		 * If the cycle of the last block is zero, the cycle of
		 * the first block must be 1. If it's not, maybe we're
		 * not looking at a log... Bail out.
		 */
		xlog_warn("XFS: Log inconsistent or not a log (last==0, first!=1)");
		return XFS_ERROR(EINVAL);
	}

	/* we have a partially zeroed log */
	last_blk = log_bbnum-1;
	if ((error = xlog_find_cycle_start(log, bp, 0, &last_blk, 0)))
		goto bp_err;

	/*
	 * Validate the answer.  Because there is no way to guarantee that
	 * the entire log is made up of log records which are the same size,
	 * we scan over the defined maximum blocks.  At this point, the maximum
	 * is not chosen to mean anything special.   XXXmiken
	 */
	num_scan_bblks = XLOG_TOTAL_REC_SHIFT(log);
	ASSERT(num_scan_bblks <= INT_MAX);

	if (last_blk < num_scan_bblks)
		num_scan_bblks = last_blk;
	start_blk = last_blk - num_scan_bblks;

	/*
	 * We search for any instances of cycle number 0 that occur before
	 * our current estimate of the head.  What we're trying to detect is
	 *        1 ... | 0 | 1 | 0...
	 *                       ^ binary search ends here
	 */
	if ((error = xlog_find_verify_cycle(log, start_blk,
					 (int)num_scan_bblks, 0, &new_blk)))
		goto bp_err;
	if (new_blk != -1)
		last_blk = new_blk;

	/*
	 * Potentially backup over partial log record write.  We don't need
	 * to search the end of the log because we know it is zero.
	 */
	if ((error = xlog_find_verify_log_record(log, start_blk,
				&last_blk, 0)) == -1) {
	    error = XFS_ERROR(EIO);
	    goto bp_err;
	} else if (error)
	    goto bp_err;

	*blk_no = last_blk;
bp_err:
	xlog_put_bp(bp);
	if (error)
		return error;
	return -1;
}	/* xlog_find_zeroed */

/*
 * This is simply a subroutine used by xlog_clear_stale_blocks() below
 * to initialize a buffer full of empty log record headers and write
 * them into the log.
 */
STATIC int
xlog_write_log_records(
	xlog_t	*log,
	int	cycle,
	int	start_block,
	int	blocks,
	int	tail_cycle,
	int	tail_block)
{
	xlog_rec_header_t	*recp;
	int			i, j;
	int			end_block = start_block + blocks;
	int			error       = 0;
	xfs_buf_t		*bp;
	char		        *buf;
	int			bufblks;

	bufblks = 1 << ffs(blocks);
	while (!(bp = xlog_get_bp(bufblks, log->l_mp))) {
		bufblks >>= 1;
		if (!bufblks)
			return ENOMEM;
	}

	buf = XFS_BUF_PTR(bp);
	recp = (xlog_rec_header_t*)buf;

	memset(buf, 0, BBSIZE);
	INT_SET(recp->h_magicno, ARCH_CONVERT, XLOG_HEADER_MAGIC_NUM);
	INT_SET(recp->h_cycle, ARCH_CONVERT, cycle);
	INT_SET(recp->h_version, ARCH_CONVERT,
			XFS_SB_VERSION_HASLOGV2(&log->l_mp->m_sb) ? 2 : 1);
	ASSIGN_ANY_LSN(recp->h_tail_lsn, tail_cycle, tail_block, ARCH_CONVERT);

	for (i = start_block; i < end_block; i += bufblks) {
		int bcount = min(bufblks, end_block - start_block);
		/* with plenty of memory, we duplicate the block
		 * right through the buffer and modify each entry
		 */
		ASSIGN_ANY_LSN(recp->h_lsn, cycle, i, ARCH_CONVERT);
		for (j = 1; j < bcount; j++) {
			buf += BBSIZE;
			recp = (xlog_rec_header_t*)buf;
			memcpy(buf, XFS_BUF_PTR(bp), BBSIZE);
			ASSIGN_ANY_LSN(recp->h_lsn, cycle, i+j, ARCH_CONVERT);
		}
		/* then write the whole lot out at once */
		error = xlog_bwrite(log, start_block, bcount, bp);
		start_block += bcount;
		buf = XFS_BUF_PTR(bp);
		recp = (xlog_rec_header_t*)buf;
	}
	xlog_put_bp(bp);

	return error;
}

/*
 * This routine is called to blow away any incomplete log writes out
 * in front of the log head.  We do this so that we won't become confused
 * if we come up, write only a little bit more, and then crash again.
 * If we leave the partial log records out there, this situation could
 * cause us to think those partial writes are valid blocks since they
 * have the current cycle number.  We get rid of them by overwriting them
 * with empty log records with the old cycle number rather than the
 * current one.
 *
 * The tail lsn is passed in rather than taken from
 * the log so that we will not write over the unmount record after a
 * clean unmount in a 512 block log.  Doing so would leave the log without
 * any valid log records in it until a new one was written.  If we crashed
 * during that time we would not be able to recover.
 */
STATIC int
xlog_clear_stale_blocks(
	xlog_t		*log,
	xfs_lsn_t	tail_lsn)
{
	int		tail_cycle, head_cycle;
	int		tail_block, head_block;
	int		tail_distance, max_distance;
	int		distance;
	int		error;

	tail_cycle = CYCLE_LSN(tail_lsn, ARCH_NOCONVERT);
	tail_block = BLOCK_LSN(tail_lsn, ARCH_NOCONVERT);
	head_cycle = log->l_curr_cycle;
	head_block = log->l_curr_block;

	/*
	 * Figure out the distance between the new head of the log
	 * and the tail.  We want to write over any blocks beyond the
	 * head that we may have written just before the crash, but
	 * we don't want to overwrite the tail of the log.
	 */
	if (head_cycle == tail_cycle) {
		/*
		 * The tail is behind the head in the physical log,
		 * so the distance from the head to the tail is the
		 * distance from the head to the end of the log plus
		 * the distance from the beginning of the log to the
		 * tail.
		 */
		if (unlikely(head_block < tail_block || head_block >= log->l_logBBsize)) {
			XFS_ERROR_REPORT("xlog_clear_stale_blocks(1)",
					 XFS_ERRLEVEL_LOW, log->l_mp);
			return XFS_ERROR(EFSCORRUPTED);
		}
		tail_distance = tail_block + (log->l_logBBsize - head_block);
	} else {
		/*
		 * The head is behind the tail in the physical log,
		 * so the distance from the head to the tail is just
		 * the tail block minus the head block.
		 */
		if (unlikely(head_block >= tail_block || head_cycle != (tail_cycle + 1))){
			XFS_ERROR_REPORT("xlog_clear_stale_blocks(2)",
					 XFS_ERRLEVEL_LOW, log->l_mp);
			return XFS_ERROR(EFSCORRUPTED);
		}
		tail_distance = tail_block - head_block;
	}

	/*
	 * If the head is right up against the tail, we can't clear
	 * anything.
	 */
	if (tail_distance <= 0) {
		ASSERT(tail_distance == 0);
		return 0;
	}

	max_distance = XLOG_TOTAL_REC_SHIFT(log);
	/*
	 * Take the smaller of the maximum amount of outstanding I/O
	 * we could have and the distance to the tail to clear out.
	 * We take the smaller so that we don't overwrite the tail and
	 * we don't waste all day writing from the head to the tail
	 * for no reason.
	 */
	max_distance = MIN(max_distance, tail_distance);

	if ((head_block + max_distance) <= log->l_logBBsize) {
		/*
		 * We can stomp all the blocks we need to without
		 * wrapping around the end of the log.  Just do it
		 * in a single write.  Use the cycle number of the
		 * current cycle minus one so that the log will look like:
		 *     n ... | n - 1 ...
		 */
		error = xlog_write_log_records(log, (head_cycle - 1),
				head_block, max_distance, tail_cycle,
				tail_block);
		if (error)
			return error;
	} else {
		/*
		 * We need to wrap around the end of the physical log in
		 * order to clear all the blocks.  Do it in two separate
		 * I/Os.  The first write should be from the head to the
		 * end of the physical log, and it should use the current
		 * cycle number minus one just like above.
		 */
		distance = log->l_logBBsize - head_block;
		error = xlog_write_log_records(log, (head_cycle - 1),
				head_block, distance, tail_cycle,
				tail_block);

		if (error)
			return error;

		/*
		 * Now write the blocks at the start of the physical log.
		 * This writes the remainder of the blocks we want to clear.
		 * It uses the current cycle number since we're now on the
		 * same cycle as the head so that we get:
		 *    n ... n ... | n - 1 ...
		 *    ^^^^^ blocks we're writing
		 */
		distance = max_distance - (log->l_logBBsize - head_block);
		error = xlog_write_log_records(log, head_cycle, 0, distance,
				tail_cycle, tail_block);
		if (error)
			return error;
	}

	return 0;
}

/******************************************************************************
 *
 *		Log recover routines
 *
 ******************************************************************************
 */

STATIC xlog_recover_t *
xlog_recover_find_tid(xlog_recover_t *q,
		      xlog_tid_t     tid)
{
	xlog_recover_t *p = q;

	while (p != NULL) {
		if (p->r_log_tid == tid)
		    break;
		p = p->r_next;
	}
	return p;
}	/* xlog_recover_find_tid */


STATIC void
xlog_recover_put_hashq(xlog_recover_t **q,
		       xlog_recover_t *trans)
{
	trans->r_next = *q;
	*q = trans;
}	/* xlog_recover_put_hashq */


STATIC void
xlog_recover_add_item(xlog_recover_item_t **itemq)
{
	xlog_recover_item_t *item;

	item = kmem_zalloc(sizeof(xlog_recover_item_t), 0);
	xlog_recover_insert_item_backq(itemq, item);
}	/* xlog_recover_add_item */


STATIC int
xlog_recover_add_to_cont_trans(xlog_recover_t	*trans,
			       xfs_caddr_t		dp,
			       int		len)
{
	xlog_recover_item_t	*item;
	xfs_caddr_t			ptr, old_ptr;
	int			old_len;

	item = trans->r_itemq;
	if (item == 0) {
		/* finish copying rest of trans header */
		xlog_recover_add_item(&trans->r_itemq);
		ptr = (xfs_caddr_t)&trans->r_theader+sizeof(xfs_trans_header_t)-len;
		memcpy(ptr, dp, len); /* d, s, l */
		return 0;
	}
	item = item->ri_prev;

	old_ptr = item->ri_buf[item->ri_cnt-1].i_addr;
	old_len = item->ri_buf[item->ri_cnt-1].i_len;

	ptr = kmem_realloc(old_ptr, len+old_len, old_len, 0);
	memcpy(&ptr[old_len], dp, len); /* d, s, l */
	item->ri_buf[item->ri_cnt-1].i_len += len;
	item->ri_buf[item->ri_cnt-1].i_addr = ptr;
	return 0;
}	/* xlog_recover_add_to_cont_trans */


/* The next region to add is the start of a new region.  It could be
 * a whole region or it could be the first part of a new region.  Because
 * of this, the assumption here is that the type and size fields of all
 * format structures fit into the first 32 bits of the structure.
 *
 * This works because all regions must be 32 bit aligned.  Therefore, we
 * either have both fields or we have neither field.  In the case we have
 * neither field, the data part of the region is zero length.  We only have
 * a log_op_header and can throw away the header since a new one will appear
 * later.  If we have at least 4 bytes, then we can determine how many regions
 * will appear in the current log item.
 */
STATIC int
xlog_recover_add_to_trans(xlog_recover_t	*trans,
			  xfs_caddr_t		dp,
			  int			len)
{
	xfs_inode_log_format_t	 *in_f;			/* any will do */
	xlog_recover_item_t	 *item;
	xfs_caddr_t		 ptr;

	if (!len)
		return 0;
	item = trans->r_itemq;
	if (item == 0) {
		ASSERT(*(uint *)dp == XFS_TRANS_HEADER_MAGIC);
		if (len == sizeof(xfs_trans_header_t))
			xlog_recover_add_item(&trans->r_itemq);
		memcpy(&trans->r_theader, dp, len); /* d, s, l */
		return 0;
	}

	ptr = kmem_alloc(len, 0);
	memcpy(ptr, dp, len);
	in_f = (xfs_inode_log_format_t *)ptr;

	if (item->ri_prev->ri_total != 0 &&
	     item->ri_prev->ri_total == item->ri_prev->ri_cnt) {
		xlog_recover_add_item(&trans->r_itemq);
	}
	item = trans->r_itemq;
	item = item->ri_prev;

	if (item->ri_total == 0) {		/* first region to be added */
		item->ri_total	= in_f->ilf_size;
		ASSERT(item->ri_total <= XLOG_MAX_REGIONS_IN_ITEM);
		item->ri_buf = kmem_zalloc((item->ri_total *
					    sizeof(xfs_log_iovec_t)), 0);
	}
	ASSERT(item->ri_total > item->ri_cnt);
	/* Description region is ri_buf[0] */
	item->ri_buf[item->ri_cnt].i_addr = ptr;
	item->ri_buf[item->ri_cnt].i_len  = len;
	item->ri_cnt++;
	return 0;
}	/* xlog_recover_add_to_trans */


STATIC void
xlog_recover_new_tid(xlog_recover_t	**q,
		     xlog_tid_t		tid,
		     xfs_lsn_t		lsn)
{
	xlog_recover_t	*trans;

	trans = kmem_zalloc(sizeof(xlog_recover_t), 0);
	trans->r_log_tid   = tid;
	trans->r_lsn	   = lsn;
	xlog_recover_put_hashq(q, trans);
}	/* xlog_recover_new_tid */


STATIC int
xlog_recover_unlink_tid(xlog_recover_t	**q,
			xlog_recover_t	*trans)
{
	xlog_recover_t	*tp;
	int		found = 0;

	ASSERT(trans != 0);
	if (trans == *q) {
		*q = (*q)->r_next;
	} else {
		tp = *q;
		while (tp != 0) {
			if (tp->r_next == trans) {
				found = 1;
				break;
			}
			tp = tp->r_next;
		}
		if (!found) {
			xlog_warn(
			     "XFS: xlog_recover_unlink_tid: trans not found");
			ASSERT(0);
			return XFS_ERROR(EIO);
		}
		tp->r_next = tp->r_next->r_next;
	}
	return 0;
}	/* xlog_recover_unlink_tid */

STATIC void
xlog_recover_insert_item_backq(xlog_recover_item_t **q,
			       xlog_recover_item_t *item)
{
	if (*q == 0) {
		item->ri_prev = item->ri_next = item;
		*q = item;
	} else {
		item->ri_next		= *q;
		item->ri_prev		= (*q)->ri_prev;
		(*q)->ri_prev		= item;
		item->ri_prev->ri_next	= item;
	}
}	/* xlog_recover_insert_item_backq */

STATIC void
xlog_recover_insert_item_frontq(xlog_recover_item_t **q,
				xlog_recover_item_t *item)
{
	xlog_recover_insert_item_backq(q, item);
	*q = item;
}	/* xlog_recover_insert_item_frontq */

STATIC int
xlog_recover_reorder_trans(xlog_t	  *log,
			   xlog_recover_t *trans)
{
    xlog_recover_item_t *first_item, *itemq, *itemq_next;

    first_item = itemq = trans->r_itemq;
    trans->r_itemq = NULL;
    do {
	itemq_next = itemq->ri_next;
	switch (ITEM_TYPE(itemq)) {
	    case XFS_LI_BUF:
	    case XFS_LI_6_1_BUF:
	    case XFS_LI_5_3_BUF: {
		xlog_recover_insert_item_frontq(&trans->r_itemq, itemq);
		break;
	    }
	    case XFS_LI_INODE:
	    case XFS_LI_6_1_INODE:
	    case XFS_LI_5_3_INODE:
	    case XFS_LI_DQUOT:
	    case XFS_LI_QUOTAOFF:
	    case XFS_LI_EFD:
	    case XFS_LI_EFI: {
		xlog_recover_insert_item_backq(&trans->r_itemq, itemq);
		break;
	    }
	    default: {
		xlog_warn(
	"XFS: xlog_recover_reorder_trans: unrecognized type of log operation");
		ASSERT(0);
		return XFS_ERROR(EIO);
	    }
	}
	itemq = itemq_next;
    } while (first_item != itemq);
    return 0;
}	/* xlog_recover_reorder_trans */


/*
 * Build up the table of buf cancel records so that we don't replay
 * cancelled data in the second pass.  For buffer records that are
 * not cancel records, there is nothing to do here so we just return.
 *
 * If we get a cancel record which is already in the table, this indicates
 * that the buffer was cancelled multiple times.  In order to ensure
 * that during pass 2 we keep the record in the table until we reach its
 * last occurrence in the log, we keep a reference count in the cancel
 * record in the table to tell us how many times we expect to see this
 * record during the second pass.
 */
STATIC void
xlog_recover_do_buffer_pass1(xlog_t			*log,
			     xfs_buf_log_format_t	*buf_f)
{
	xfs_buf_cancel_t	*bcp;
	xfs_buf_cancel_t	*nextp;
	xfs_buf_cancel_t	*prevp;
	xfs_buf_cancel_t	**bucket;
	xfs_buf_log_format_v1_t	*obuf_f;
	xfs_daddr_t		blkno=0;
	uint			len=0;
	ushort			flags=0;

	switch (buf_f->blf_type) {
	case XFS_LI_BUF:
		blkno = buf_f->blf_blkno;
		len = buf_f->blf_len;
		flags = buf_f->blf_flags;
		break;
	case XFS_LI_6_1_BUF:
	case XFS_LI_5_3_BUF:
		obuf_f = (xfs_buf_log_format_v1_t*)buf_f;
		blkno = (xfs_daddr_t) obuf_f->blf_blkno;
		len = obuf_f->blf_len;
		flags = obuf_f->blf_flags;
		break;
	}

	/*
	 * If this isn't a cancel buffer item, then just return.
	 */
	if (!(flags & XFS_BLI_CANCEL)) {
		return;
	}

	/*
	 * Insert an xfs_buf_cancel record into the hash table of
	 * them.  If there is already an identical record, bump
	 * its reference count.
	 */
	bucket = &log->l_buf_cancel_table[(__uint64_t)blkno %
					  XLOG_BC_TABLE_SIZE];
	/*
	 * If the hash bucket is empty then just insert a new record into
	 * the bucket.
	 */
	if (*bucket == NULL) {
		bcp = (xfs_buf_cancel_t*)kmem_alloc(sizeof(xfs_buf_cancel_t),
						    KM_SLEEP);
		bcp->bc_blkno = blkno;
		bcp->bc_len = len;
		bcp->bc_refcount = 1;
		bcp->bc_next = NULL;
		*bucket = bcp;
		return;
	}

	/*
	 * The hash bucket is not empty, so search for duplicates of our
	 * record.  If we find one them just bump its refcount.  If not
	 * then add us at the end of the list.
	 */
	prevp = NULL;
	nextp = *bucket;
	while (nextp != NULL) {
		if (nextp->bc_blkno == blkno && nextp->bc_len == len) {
			nextp->bc_refcount++;
			return;
		}
		prevp = nextp;
		nextp = nextp->bc_next;
	}
	ASSERT(prevp != NULL);
	bcp = (xfs_buf_cancel_t*)kmem_alloc(sizeof(xfs_buf_cancel_t),
					    KM_SLEEP);
	bcp->bc_blkno = blkno;
	bcp->bc_len = len;
	bcp->bc_refcount = 1;
	bcp->bc_next = NULL;
	prevp->bc_next = bcp;
}

/*
 * Check to see whether the buffer being recovered has a corresponding
 * entry in the buffer cancel record table.  If it does then return 1
 * so that it will be cancelled, otherwise return 0.  If the buffer is
 * actually a buffer cancel item (XFS_BLI_CANCEL is set), then decrement
 * the refcount on the entry in the table and remove it from the table
 * if this is the last reference.
 *
 * We remove the cancel record from the table when we encounter its
 * last occurrence in the log so that if the same buffer is re-used
 * again after its last cancellation we actually replay the changes
 * made at that point.
 */
STATIC int
xlog_recover_do_buffer_pass2(xlog_t			*log,
			     xfs_buf_log_format_t	*buf_f)
{
	xfs_buf_cancel_t	*bcp;
	xfs_buf_cancel_t	*prevp;
	xfs_buf_cancel_t	**bucket;
	xfs_buf_log_format_v1_t	*obuf_f;
	xfs_daddr_t		blkno=0;
	ushort			flags=0;
	uint			len=0;


	switch (buf_f->blf_type) {
	case XFS_LI_BUF:
		blkno = buf_f->blf_blkno;
		flags = buf_f->blf_flags;
		len = buf_f->blf_len;
		break;
	case XFS_LI_6_1_BUF:
	case XFS_LI_5_3_BUF:
		obuf_f = (xfs_buf_log_format_v1_t*)buf_f;
		blkno = (xfs_daddr_t) obuf_f->blf_blkno;
		flags = obuf_f->blf_flags;
		len = (xfs_daddr_t) obuf_f->blf_len;
		break;
	}
	if (log->l_buf_cancel_table == NULL) {
		/*
		 * There is nothing in the table built in pass one,
		 * so this buffer must not be cancelled.
		 */
		ASSERT(!(flags & XFS_BLI_CANCEL));
		return 0;
	}

	bucket = &log->l_buf_cancel_table[(__uint64_t)blkno %
					  XLOG_BC_TABLE_SIZE];
	bcp = *bucket;
	if (bcp == NULL) {
		/*
		 * There is no corresponding entry in the table built
		 * in pass one, so this buffer has not been cancelled.
		 */
		ASSERT(!(flags & XFS_BLI_CANCEL));
		return 0;
	}

	/*
	 * Search for an entry in the buffer cancel table that
	 * matches our buffer.
	 */
	prevp = NULL;
	while (bcp != NULL) {
		if (bcp->bc_blkno == blkno && bcp->bc_len == len) {
			/*
			 * We've go a match, so return 1 so that the
			 * recovery of this buffer is cancelled.
			 * If this buffer is actually a buffer cancel
			 * log item, then decrement the refcount on the
			 * one in the table and remove it if this is the
			 * last reference.
			 */
			if (flags & XFS_BLI_CANCEL) {
				bcp->bc_refcount--;
				if (bcp->bc_refcount == 0) {
					if (prevp == NULL) {
						*bucket = bcp->bc_next;
					} else {
						prevp->bc_next = bcp->bc_next;
					}
					kmem_free(bcp,
						  sizeof(xfs_buf_cancel_t));
				}
			}
			return 1;
		}
		prevp = bcp;
		bcp = bcp->bc_next;
	}
	/*
	 * We didn't find a corresponding entry in the table, so
	 * return 0 so that the buffer is NOT cancelled.
	 */
	ASSERT(!(flags & XFS_BLI_CANCEL));
	return 0;
}


/*
 * Perform recovery for a buffer full of inodes.  In these buffers,
 * the only data which should be recovered is that which corresponds
 * to the di_next_unlinked pointers in the on disk inode structures.
 * The rest of the data for the inodes is always logged through the
 * inodes themselves rather than the inode buffer and is recovered
 * in xlog_recover_do_inode_trans().
 *
 * The only time when buffers full of inodes are fully recovered is
 * when the buffer is full of newly allocated inodes.  In this case
 * the buffer will not be marked as an inode buffer and so will be
 * sent to xlog_recover_do_reg_buffer() below during recovery.
 */
STATIC int
xlog_recover_do_inode_buffer(xfs_mount_t		*mp,
			     xlog_recover_item_t	*item,
			     xfs_buf_t			*bp,
			     xfs_buf_log_format_t	*buf_f)
{
	int			i;
	int			item_index;
	int			bit;
	int			nbits;
	int			reg_buf_offset;
	int			reg_buf_bytes;
	int			next_unlinked_offset;
	int			inodes_per_buf;
	xfs_agino_t		*logged_nextp;
	xfs_agino_t		*buffer_nextp;
	xfs_buf_log_format_v1_t	*obuf_f;
	unsigned int		*data_map=NULL;
	unsigned int		map_size=0;

	switch (buf_f->blf_type) {
	case XFS_LI_BUF:
		data_map = buf_f->blf_data_map;
		map_size = buf_f->blf_map_size;
		break;
	case XFS_LI_6_1_BUF:
	case XFS_LI_5_3_BUF:
		obuf_f = (xfs_buf_log_format_v1_t*)buf_f;
		data_map = obuf_f->blf_data_map;
		map_size = obuf_f->blf_map_size;
		break;
	}
	/*
	 * Set the variables corresponding to the current region to
	 * 0 so that we'll initialize them on the first pass through
	 * the loop.
	 */
	reg_buf_offset = 0;
	reg_buf_bytes = 0;
	bit = 0;
	nbits = 0;
	item_index = 0;
	inodes_per_buf = XFS_BUF_COUNT(bp) >> mp->m_sb.sb_inodelog;
	for (i = 0; i < inodes_per_buf; i++) {
		next_unlinked_offset = (i * mp->m_sb.sb_inodesize) +
			offsetof(xfs_dinode_t, di_next_unlinked);

		while (next_unlinked_offset >=
		       (reg_buf_offset + reg_buf_bytes)) {
			/*
			 * The next di_next_unlinked field is beyond
			 * the current logged region.  Find the next
			 * logged region that contains or is beyond
			 * the current di_next_unlinked field.
			 */
			bit += nbits;
			bit = xfs_next_bit(data_map, map_size, bit);

			/*
			 * If there are no more logged regions in the
			 * buffer, then we're done.
			 */
			if (bit == -1) {
				return 0;
			}

			nbits = xfs_contig_bits(data_map, map_size,
							 bit);
			reg_buf_offset = bit << XFS_BLI_SHIFT;
			reg_buf_bytes = nbits << XFS_BLI_SHIFT;
			item_index++;
		}

		/*
		 * If the current logged region starts after the current
		 * di_next_unlinked field, then move on to the next
		 * di_next_unlinked field.
		 */
		if (next_unlinked_offset < reg_buf_offset) {
			continue;
		}

		ASSERT(item->ri_buf[item_index].i_addr != NULL);
		ASSERT((item->ri_buf[item_index].i_len % XFS_BLI_CHUNK) == 0);
		ASSERT((reg_buf_offset + reg_buf_bytes) <= XFS_BUF_COUNT(bp));

		/*
		 * The current logged region contains a copy of the
		 * current di_next_unlinked field.  Extract its value
		 * and copy it to the buffer copy.
		 */
		logged_nextp = (xfs_agino_t *)
			       ((char *)(item->ri_buf[item_index].i_addr) +
				(next_unlinked_offset - reg_buf_offset));
		if (unlikely(*logged_nextp == 0)) {
			xfs_fs_cmn_err(CE_ALERT, mp,
				"bad inode buffer log record (ptr = 0x%p, bp = 0x%p).  XFS trying to replay bad (0) inode di_next_unlinked field",
				item, bp);
			XFS_ERROR_REPORT("xlog_recover_do_inode_buf",
					 XFS_ERRLEVEL_LOW, mp);
			return XFS_ERROR(EFSCORRUPTED);
		}

		buffer_nextp = (xfs_agino_t *)xfs_buf_offset(bp,
					      next_unlinked_offset);
		INT_SET(*buffer_nextp, ARCH_CONVERT, *logged_nextp);
	}

	return 0;
}	/* xlog_recover_do_inode_buffer */

/*
 * Perform a 'normal' buffer recovery.  Each logged region of the
 * buffer should be copied over the corresponding region in the
 * given buffer.  The bitmap in the buf log format structure indicates
 * where to place the logged data.
 */
/*ARGSUSED*/
STATIC void
xlog_recover_do_reg_buffer(xfs_mount_t		*mp,
			   xlog_recover_item_t	*item,
			   xfs_buf_t		*bp,
			   xfs_buf_log_format_t	*buf_f)
{
	int			i;
	int			bit;
	int			nbits;
	xfs_buf_log_format_v1_t	*obuf_f;
	unsigned int		*data_map=NULL;
	unsigned int		map_size=0;
	int                     error;

	switch (buf_f->blf_type) {
	case XFS_LI_BUF:
		data_map = buf_f->blf_data_map;
		map_size = buf_f->blf_map_size;
		break;
	case XFS_LI_6_1_BUF:
	case XFS_LI_5_3_BUF:
		obuf_f = (xfs_buf_log_format_v1_t*)buf_f;
		data_map = obuf_f->blf_data_map;
		map_size = obuf_f->blf_map_size;
		break;
	}
	bit = 0;
	i = 1;  /* 0 is the buf format structure */
	while (1) {
		bit = xfs_next_bit(data_map, map_size, bit);
		if (bit == -1)
			break;
		nbits = xfs_contig_bits(data_map, map_size, bit);
		ASSERT(item->ri_buf[i].i_addr != 0);
		ASSERT(item->ri_buf[i].i_len % XFS_BLI_CHUNK == 0);
		ASSERT(XFS_BUF_COUNT(bp) >=
		       ((uint)bit << XFS_BLI_SHIFT)+(nbits<<XFS_BLI_SHIFT));

		/*
		 * Do a sanity check if this is a dquot buffer. Just checking
		 * the first dquot in the buffer should do. XXXThis is
		 * probably a good thing to do for other buf types also.
		 */
		error = 0;
		if (buf_f->blf_flags & (XFS_BLI_UDQUOT_BUF|XFS_BLI_GDQUOT_BUF)) {
			error = xfs_qm_dqcheck((xfs_disk_dquot_t *)
					       item->ri_buf[i].i_addr,
					       -1, 0, XFS_QMOPT_DOWARN,
					       "dquot_buf_recover");
		}
		if (!error)
			memcpy(xfs_buf_offset(bp,
				(uint)bit << XFS_BLI_SHIFT),	/* dest */
				item->ri_buf[i].i_addr,		/* source */
				nbits<<XFS_BLI_SHIFT);		/* length */
		i++;
		bit += nbits;
	}

	/* Shouldn't be any more regions */
	ASSERT(i == item->ri_total);
}	/* xlog_recover_do_reg_buffer */

/*
 * Do some primitive error checking on ondisk dquot data structures.
 */
int
xfs_qm_dqcheck(
	xfs_disk_dquot_t *ddq,
	xfs_dqid_t	 id,
	uint		 type,	  /* used only when IO_dorepair is true */
	uint		 flags,
	char		 *str)
{
	xfs_dqblk_t	 *d = (xfs_dqblk_t *)ddq;
	int		errs = 0;

	/*
	 * We can encounter an uninitialized dquot buffer for 2 reasons:
	 * 1. If we crash while deleting the quotainode(s), and those blks got
	 *    used for user data. This is because we take the path of regular
	 *    file deletion; however, the size field of quotainodes is never
	 *    updated, so all the tricks that we play in itruncate_finish
	 *    don't quite matter.
	 *
	 * 2. We don't play the quota buffers when there's a quotaoff logitem.
	 *    But the allocation will be replayed so we'll end up with an
	 *    uninitialized quota block.
	 *
	 * This is all fine; things are still consistent, and we haven't lost
	 * any quota information. Just don't complain about bad dquot blks.
	 */
	if (INT_GET(ddq->d_magic, ARCH_CONVERT) != XFS_DQUOT_MAGIC) {
		if (flags & XFS_QMOPT_DOWARN)
			cmn_err(CE_ALERT,
			"%s : XFS dquot ID 0x%x, magic 0x%x != 0x%x",
			str, id,
			INT_GET(ddq->d_magic, ARCH_CONVERT), XFS_DQUOT_MAGIC);
		errs++;
	}
	if (INT_GET(ddq->d_version, ARCH_CONVERT) != XFS_DQUOT_VERSION) {
		if (flags & XFS_QMOPT_DOWARN)
			cmn_err(CE_ALERT,
			"%s : XFS dquot ID 0x%x, version 0x%x != 0x%x",
			str, id,
			INT_GET(ddq->d_magic, ARCH_CONVERT), XFS_DQUOT_VERSION);
		errs++;
	}

	if (INT_GET(ddq->d_flags, ARCH_CONVERT) != XFS_DQ_USER &&
	    INT_GET(ddq->d_flags, ARCH_CONVERT) != XFS_DQ_GROUP) {
		if (flags & XFS_QMOPT_DOWARN)
			cmn_err(CE_ALERT,
			"%s : XFS dquot ID 0x%x, unknown flags 0x%x",
			str, id, INT_GET(ddq->d_flags, ARCH_CONVERT));
		errs++;
	}

	if (id != -1 && id != INT_GET(ddq->d_id, ARCH_CONVERT)) {
		if (flags & XFS_QMOPT_DOWARN)
			cmn_err(CE_ALERT,
			"%s : ondisk-dquot 0x%x, ID mismatch: "
			"0x%x expected, found id 0x%x",
			str, ddq, id, INT_GET(ddq->d_id, ARCH_CONVERT));
		errs++;
	}

	if (! errs) {
		if (INT_GET(ddq->d_blk_softlimit, ARCH_CONVERT) &&
		    INT_GET(ddq->d_bcount, ARCH_CONVERT) >=
				INT_GET(ddq->d_blk_softlimit, ARCH_CONVERT)) {
			if (INT_ISZERO(ddq->d_btimer, ARCH_CONVERT) &&
			    !INT_ISZERO(ddq->d_id, ARCH_CONVERT)) {
				if (flags & XFS_QMOPT_DOWARN)
					cmn_err(CE_ALERT,
					"%s : Dquot ID 0x%x (0x%x) "
					"BLK TIMER NOT STARTED",
					str, (int)
					INT_GET(ddq->d_id, ARCH_CONVERT), ddq);
				errs++;
			}
		}
		if (INT_GET(ddq->d_ino_softlimit, ARCH_CONVERT) &&
		    INT_GET(ddq->d_icount, ARCH_CONVERT) >=
				INT_GET(ddq->d_ino_softlimit, ARCH_CONVERT)) {
			if (INT_ISZERO(ddq->d_itimer, ARCH_CONVERT) &&
			    !INT_ISZERO(ddq->d_id, ARCH_CONVERT)) {
				if (flags & XFS_QMOPT_DOWARN)
					cmn_err(CE_ALERT,
					"%s : Dquot ID 0x%x (0x%x) "
					"INODE TIMER NOT STARTED",
					str, (int)
					INT_GET(ddq->d_id, ARCH_CONVERT), ddq);
				errs++;
			}
		}
	}

	if (!errs || !(flags & XFS_QMOPT_DQREPAIR))
		return errs;

	if (flags & XFS_QMOPT_DOWARN)
		cmn_err(CE_NOTE, "Re-initializing dquot ID 0x%x", id);

	/*
	 * Typically, a repair is only requested by quotacheck.
	 */
	ASSERT(id != -1);
	ASSERT(flags & XFS_QMOPT_DQREPAIR);
	memset(d, 0, sizeof(xfs_dqblk_t));
	INT_SET(d->dd_diskdq.d_magic, ARCH_CONVERT, XFS_DQUOT_MAGIC);
	INT_SET(d->dd_diskdq.d_version, ARCH_CONVERT, XFS_DQUOT_VERSION);
	INT_SET(d->dd_diskdq.d_id, ARCH_CONVERT, id);
	INT_SET(d->dd_diskdq.d_flags, ARCH_CONVERT, type);

	return errs;
}

/*
 * Perform a dquot buffer recovery.
 * Simple algorithm: if we have found a QUOTAOFF logitem of the same type
 * (ie. USR or GRP), then just toss this buffer away; don't recover it.
 * Else, treat it as a regular buffer and do recovery.
 */
STATIC void
xlog_recover_do_dquot_buffer(
	xfs_mount_t		*mp,
	xlog_t			*log,
	xlog_recover_item_t	*item,
	xfs_buf_t		*bp,
	xfs_buf_log_format_t	*buf_f)
{
	uint type;

	/*
	 * Filesystems are required to send in quota flags at mount time.
	 */
	if (mp->m_qflags == 0) {
		return;
	}

	type = 0;
	if (buf_f->blf_flags & XFS_BLI_UDQUOT_BUF)
		type |= XFS_DQ_USER;
	if (buf_f->blf_flags & XFS_BLI_GDQUOT_BUF)
		type |= XFS_DQ_GROUP;
	/*
	 * This type of quotas was turned off, so ignore this buffer
	 */
	if (log->l_quotaoffs_flag & type)
		return;

	xlog_recover_do_reg_buffer(mp, item, bp, buf_f);
}

/*
 * This routine replays a modification made to a buffer at runtime.
 * There are actually two types of buffer, regular and inode, which
 * are handled differently.  Inode buffers are handled differently
 * in that we only recover a specific set of data from them, namely
 * the inode di_next_unlinked fields.  This is because all other inode
 * data is actually logged via inode records and any data we replay
 * here which overlaps that may be stale.
 *
 * When meta-data buffers are freed at run time we log a buffer item
 * with the XFS_BLI_CANCEL bit set to indicate that previous copies
 * of the buffer in the log should not be replayed at recovery time.
 * This is so that if the blocks covered by the buffer are reused for
 * file data before we crash we don't end up replaying old, freed
 * meta-data into a user's file.
 *
 * To handle the cancellation of buffer log items, we make two passes
 * over the log during recovery.  During the first we build a table of
 * those buffers which have been cancelled, and during the second we
 * only replay those buffers which do not have corresponding cancel
 * records in the table.  See xlog_recover_do_buffer_pass[1,2] above
 * for more details on the implementation of the table of cancel records.
 */
STATIC int
xlog_recover_do_buffer_trans(xlog_t		 *log,
			     xlog_recover_item_t *item,
			     int		 pass)
{
	xfs_buf_log_format_t	*buf_f;
	xfs_buf_log_format_v1_t	*obuf_f;
	xfs_mount_t		*mp;
	xfs_buf_t		*bp;
	int			error;
	int			cancel;
	xfs_daddr_t		blkno;
	int			len;
	ushort			flags;

	buf_f = (xfs_buf_log_format_t *)item->ri_buf[0].i_addr;

	if (pass == XLOG_RECOVER_PASS1) {
		/*
		 * In this pass we're only looking for buf items
		 * with the XFS_BLI_CANCEL bit set.
		 */
		xlog_recover_do_buffer_pass1(log, buf_f);
		return 0;
	} else {
		/*
		 * In this pass we want to recover all the buffers
		 * which have not been cancelled and are not
		 * cancellation buffers themselves.  The routine
		 * we call here will tell us whether or not to
		 * continue with the replay of this buffer.
		 */
		cancel = xlog_recover_do_buffer_pass2(log, buf_f);
		if (cancel) {
			return 0;
		}
	}
	switch (buf_f->blf_type) {
	      case XFS_LI_BUF:
		blkno = buf_f->blf_blkno;
		len = buf_f->blf_len;
		flags = buf_f->blf_flags;
		break;
	      case XFS_LI_6_1_BUF:
	      case XFS_LI_5_3_BUF:
		obuf_f = (xfs_buf_log_format_v1_t*)buf_f;
		blkno = obuf_f->blf_blkno;
		len = obuf_f->blf_len;
		flags = obuf_f->blf_flags;
		break;
	      default:
		xfs_fs_cmn_err(CE_ALERT, log->l_mp,
			"xfs_log_recover: unknown buffer type 0x%x, dev 0x%x",
			buf_f->blf_type, log->l_dev);
		XFS_ERROR_REPORT("xlog_recover_do_buffer_trans",
				 XFS_ERRLEVEL_LOW, log->l_mp);
		return XFS_ERROR(EFSCORRUPTED);
	}

	mp = log->l_mp;
	if (flags & XFS_BLI_INODE_BUF) {
		bp = xfs_buf_read_flags(mp->m_ddev_targp, blkno, len,
								XFS_BUF_LOCK);
	} else {
		bp = xfs_buf_read(mp->m_ddev_targp, blkno, len, 0);
	}
	if (XFS_BUF_ISERROR(bp)) {
		xfs_ioerror_alert("xlog_recover_do..(read#1)", log->l_mp,
				  bp, blkno);
		error = XFS_BUF_GETERROR(bp);
		xfs_buf_relse(bp);
		return error;
	}

	error = 0;
	if (flags & XFS_BLI_INODE_BUF) {
		error = xlog_recover_do_inode_buffer(mp, item, bp, buf_f);
	} else if (flags & (XFS_BLI_UDQUOT_BUF | XFS_BLI_GDQUOT_BUF)) {
		xlog_recover_do_dquot_buffer(mp, log, item, bp, buf_f);
	} else {
		xlog_recover_do_reg_buffer(mp, item, bp, buf_f);
	}
	if (error)
		return XFS_ERROR(error);

	/*
	 * Perform delayed write on the buffer.  Asynchronous writes will be
	 * slower when taking into account all the buffers to be flushed.
	 *
	 * Also make sure that only inode buffers with good sizes stay in
	 * the buffer cache.  The kernel moves inodes in buffers of 1 block
	 * or XFS_INODE_CLUSTER_SIZE bytes, whichever is bigger.  The inode
	 * buffers in the log can be a different size if the log was generated
	 * by an older kernel using unclustered inode buffers or a newer kernel
	 * running with a different inode cluster size.  Regardless, if the
	 * the inode buffer size isn't MAX(blocksize, XFS_INODE_CLUSTER_SIZE)
	 * for *our* value of XFS_INODE_CLUSTER_SIZE, then we need to keep
	 * the buffer out of the buffer cache so that the buffer won't
	 * overlap with future reads of those inodes.
	 */
	if (XFS_DINODE_MAGIC ==
	    INT_GET(*((__uint16_t *)(xfs_buf_offset(bp, 0))), ARCH_CONVERT) &&
	    (XFS_BUF_COUNT(bp) != MAX(log->l_mp->m_sb.sb_blocksize,
			(__uint32_t)XFS_INODE_CLUSTER_SIZE(log->l_mp)))) {
		XFS_BUF_STALE(bp);
		error = xfs_bwrite(mp, bp);
	} else {
		ASSERT(XFS_BUF_FSPRIVATE(bp, void *) == NULL ||
		       XFS_BUF_FSPRIVATE(bp, xfs_mount_t *) == mp);
		XFS_BUF_SET_FSPRIVATE(bp, mp);
		XFS_BUF_SET_IODONE_FUNC(bp, xlog_recover_iodone);
		xfs_bdwrite(mp, bp);
	}

	return (error);
}	/* xlog_recover_do_buffer_trans */

STATIC int
xlog_recover_do_inode_trans(xlog_t		*log,
			    xlog_recover_item_t *item,
			    int			pass)
{
	xfs_inode_log_format_t	*in_f;
	xfs_mount_t		*mp;
	xfs_buf_t		*bp;
	xfs_imap_t		imap;
	xfs_dinode_t		*dip;
	xfs_ino_t		ino;
	int			len;
	xfs_caddr_t		src;
	xfs_caddr_t		dest;
	int			error;
	int			attr_index;
	uint			fields;
	xfs_dinode_core_t	*dicp;

	if (pass == XLOG_RECOVER_PASS1) {
		return 0;
	}

	in_f = (xfs_inode_log_format_t *)item->ri_buf[0].i_addr;
	ino = in_f->ilf_ino;
	mp = log->l_mp;
	if (ITEM_TYPE(item) == XFS_LI_INODE) {
		imap.im_blkno = (xfs_daddr_t)in_f->ilf_blkno;
		imap.im_len = in_f->ilf_len;
		imap.im_boffset = in_f->ilf_boffset;
	} else {
		/*
		 * It's an old inode format record.  We don't know where
		 * its cluster is located on disk, and we can't allow
		 * xfs_imap() to figure it out because the inode btrees
		 * are not ready to be used.  Therefore do not pass the
		 * XFS_IMAP_LOOKUP flag to xfs_imap().  This will give
		 * us only the single block in which the inode lives
		 * rather than its cluster, so we must make sure to
		 * invalidate the buffer when we write it out below.
		 */
		imap.im_blkno = 0;
		xfs_imap(log->l_mp, 0, ino, &imap, 0);
	}
	bp = xfs_buf_read_flags(mp->m_ddev_targp, imap.im_blkno, imap.im_len,
								XFS_BUF_LOCK);
	if (XFS_BUF_ISERROR(bp)) {
		xfs_ioerror_alert("xlog_recover_do..(read#2)", mp,
				  bp, imap.im_blkno);
		error = XFS_BUF_GETERROR(bp);
		xfs_buf_relse(bp);
		return error;
	}
	error = 0;
	ASSERT(in_f->ilf_fields & XFS_ILOG_CORE);
	dip = (xfs_dinode_t *)xfs_buf_offset(bp, imap.im_boffset);

	/*
	 * Make sure the place we're flushing out to really looks
	 * like an inode!
	 */
	if (unlikely(INT_GET(dip->di_core.di_magic, ARCH_CONVERT) != XFS_DINODE_MAGIC)) {
		xfs_buf_relse(bp);
		xfs_fs_cmn_err(CE_ALERT, mp,
			"xfs_inode_recover: Bad inode magic number, dino ptr = 0x%p, dino bp = 0x%p, ino = %Ld",
			dip, bp, ino);
		XFS_ERROR_REPORT("xlog_recover_do_inode_trans(1)",
				 XFS_ERRLEVEL_LOW, mp);
		return XFS_ERROR(EFSCORRUPTED);
	}
	dicp = (xfs_dinode_core_t*)(item->ri_buf[1].i_addr);
	if (unlikely(dicp->di_magic != XFS_DINODE_MAGIC)) {
		xfs_buf_relse(bp);
		xfs_fs_cmn_err(CE_ALERT, mp,
			"xfs_inode_recover: Bad inode log record, rec ptr 0x%p, ino %Ld",
			item, ino);
		XFS_ERROR_REPORT("xlog_recover_do_inode_trans(2)",
				 XFS_ERRLEVEL_LOW, mp);
		return XFS_ERROR(EFSCORRUPTED);
	}
	if (unlikely((dicp->di_mode & IFMT) == IFREG)) {
		if ((dicp->di_format != XFS_DINODE_FMT_EXTENTS) &&
		    (dicp->di_format != XFS_DINODE_FMT_BTREE)) {
			XFS_CORRUPTION_ERROR("xlog_recover_do_inode_trans(3)",
					 XFS_ERRLEVEL_LOW, mp, dicp);
			xfs_buf_relse(bp);
			xfs_fs_cmn_err(CE_ALERT, mp,
				"xfs_inode_recover: Bad regular inode log record, rec ptr 0x%p, ino ptr = 0x%p, ino bp = 0x%p, ino %Ld",
				item, dip, bp, ino);
			return XFS_ERROR(EFSCORRUPTED);
		}
	} else if (unlikely((dicp->di_mode & IFMT) == IFDIR)) {
		if ((dicp->di_format != XFS_DINODE_FMT_EXTENTS) &&
		    (dicp->di_format != XFS_DINODE_FMT_BTREE) &&
		    (dicp->di_format != XFS_DINODE_FMT_LOCAL)) {
			XFS_CORRUPTION_ERROR("xlog_recover_do_inode_trans(4)",
					     XFS_ERRLEVEL_LOW, mp, dicp);
			xfs_buf_relse(bp);
			xfs_fs_cmn_err(CE_ALERT, mp,
				"xfs_inode_recover: Bad dir inode log record, rec ptr 0x%p, ino ptr = 0x%p, ino bp = 0x%p, ino %Ld",
				item, dip, bp, ino);
			return XFS_ERROR(EFSCORRUPTED);
		}
	}
	if (unlikely(dicp->di_nextents + dicp->di_anextents > dicp->di_nblocks)){
		XFS_CORRUPTION_ERROR("xlog_recover_do_inode_trans(5)",
				     XFS_ERRLEVEL_LOW, mp, dicp);
		xfs_buf_relse(bp);
		xfs_fs_cmn_err(CE_ALERT, mp,
			"xfs_inode_recover: Bad inode log record, rec ptr 0x%p, dino ptr 0x%p, dino bp 0x%p, ino %Ld, total extents = %d, nblocks = %Ld",
			item, dip, bp, ino,
			dicp->di_nextents + dicp->di_anextents,
			dicp->di_nblocks);
		return XFS_ERROR(EFSCORRUPTED);
	}
	if (unlikely(dicp->di_forkoff > mp->m_sb.sb_inodesize)) {
		XFS_CORRUPTION_ERROR("xlog_recover_do_inode_trans(6)",
				     XFS_ERRLEVEL_LOW, mp, dicp);
		xfs_buf_relse(bp);
		xfs_fs_cmn_err(CE_ALERT, mp,
			"xfs_inode_recover: Bad inode log rec ptr 0x%p, dino ptr 0x%p, dino bp 0x%p, ino %Ld, forkoff 0x%x",
			item, dip, bp, ino, dicp->di_forkoff);
		return XFS_ERROR(EFSCORRUPTED);
	}
	if (unlikely(item->ri_buf[1].i_len > sizeof(xfs_dinode_core_t))) {
		XFS_CORRUPTION_ERROR("xlog_recover_do_inode_trans(7)",
				     XFS_ERRLEVEL_LOW, mp, dicp);
		xfs_buf_relse(bp);
		xfs_fs_cmn_err(CE_ALERT, mp,
			"xfs_inode_recover: Bad inode log record length %d, rec ptr 0x%p",
			item->ri_buf[1].i_len, item);
		return XFS_ERROR(EFSCORRUPTED);
	}

	/* The core is in in-core format */
	xfs_xlate_dinode_core((xfs_caddr_t)&dip->di_core,
			      (xfs_dinode_core_t*)item->ri_buf[1].i_addr,
			      -1, ARCH_CONVERT);
	/* the rest is in on-disk format */
	if (item->ri_buf[1].i_len > sizeof(xfs_dinode_core_t)) {
		memcpy((xfs_caddr_t) dip + sizeof(xfs_dinode_core_t),
			item->ri_buf[1].i_addr + sizeof(xfs_dinode_core_t),
			item->ri_buf[1].i_len  - sizeof(xfs_dinode_core_t));
	}

	fields = in_f->ilf_fields;
	switch (fields & (XFS_ILOG_DEV | XFS_ILOG_UUID)) {
	case XFS_ILOG_DEV:
		INT_SET(dip->di_u.di_dev, ARCH_CONVERT, in_f->ilf_u.ilfu_rdev);

		break;
	case XFS_ILOG_UUID:
		dip->di_u.di_muuid = in_f->ilf_u.ilfu_uuid;
		break;
	}

	if (in_f->ilf_size == 2)
		goto write_inode_buffer;
	len = item->ri_buf[2].i_len;
	src = item->ri_buf[2].i_addr;
	ASSERT(in_f->ilf_size <= 4);
	ASSERT((in_f->ilf_size == 3) || (fields & XFS_ILOG_AFORK));
	ASSERT(!(fields & XFS_ILOG_DFORK) ||
	       (len == in_f->ilf_dsize));

	switch (fields & XFS_ILOG_DFORK) {
	case XFS_ILOG_DDATA:
	case XFS_ILOG_DEXT:
		memcpy(&dip->di_u, src, len);
		break;

	case XFS_ILOG_DBROOT:
		xfs_bmbt_to_bmdr((xfs_bmbt_block_t *)src, len,
				 &(dip->di_u.di_bmbt),
				 XFS_DFORK_DSIZE(dip, mp));
		break;

	default:
		/*
		 * There are no data fork flags set.
		 */
		ASSERT((fields & XFS_ILOG_DFORK) == 0);
		break;
	}

	/*
	 * If we logged any attribute data, recover it.  There may or
	 * may not have been any other non-core data logged in this
	 * transaction.
	 */
	if (in_f->ilf_fields & XFS_ILOG_AFORK) {
		if (in_f->ilf_fields & XFS_ILOG_DFORK) {
			attr_index = 3;
		} else {
			attr_index = 2;
		}
		len = item->ri_buf[attr_index].i_len;
		src = item->ri_buf[attr_index].i_addr;
		ASSERT(len == in_f->ilf_asize);

		switch (in_f->ilf_fields & XFS_ILOG_AFORK) {
		case XFS_ILOG_ADATA:
		case XFS_ILOG_AEXT:
			dest = XFS_DFORK_APTR(dip);
			ASSERT(len <= XFS_DFORK_ASIZE(dip, mp));
			memcpy(dest, src, len);
			break;

		case XFS_ILOG_ABROOT:
			dest = XFS_DFORK_APTR(dip);
			xfs_bmbt_to_bmdr((xfs_bmbt_block_t *)src, len,
					 (xfs_bmdr_block_t*)dest,
					 XFS_DFORK_ASIZE(dip, mp));
			break;

		default:
			xlog_warn("XFS: xlog_recover_do_inode_trans: Illegal flag");
			ASSERT(0);
			xfs_buf_relse(bp);
			return XFS_ERROR(EIO);
		}
	}


write_inode_buffer:
	if (ITEM_TYPE(item) == XFS_LI_INODE) {
		ASSERT(XFS_BUF_FSPRIVATE(bp, void *) == NULL ||
		       XFS_BUF_FSPRIVATE(bp, xfs_mount_t *) == mp);
		XFS_BUF_SET_FSPRIVATE(bp, mp);
		XFS_BUF_SET_IODONE_FUNC(bp, xlog_recover_iodone);
		xfs_bdwrite(mp, bp);
	} else {
		XFS_BUF_STALE(bp);
		error = xfs_bwrite(mp, bp);
	}

	return (error);
}	/* xlog_recover_do_inode_trans */


/*
 * Recover QUOTAOFF records. We simply make a note of it in the xlog_t
 * structure, so that we know not to do any dquot item or dquot buffer recovery,
 * of that type.
 */
STATIC int
xlog_recover_do_quotaoff_trans(xlog_t			*log,
			       xlog_recover_item_t	*item,
			       int			pass)
{
	xfs_qoff_logformat_t *qoff_f;

	if (pass == XLOG_RECOVER_PASS2) {
		return (0);
	}

	qoff_f = (xfs_qoff_logformat_t *)item->ri_buf[0].i_addr;
	ASSERT(qoff_f);

	/*
	 * The logitem format's flag tells us if this was user quotaoff,
	 * group quotaoff or both.
	 */
	if (qoff_f->qf_flags & XFS_UQUOTA_ACCT)
		log->l_quotaoffs_flag |= XFS_DQ_USER;
	if (qoff_f->qf_flags & XFS_GQUOTA_ACCT)
		log->l_quotaoffs_flag |= XFS_DQ_GROUP;

	return (0);
}


/*
 * Recover a dquot record
 */
STATIC int
xlog_recover_do_dquot_trans(xlog_t		*log,
			    xlog_recover_item_t *item,
			    int			pass)
{
	xfs_mount_t		*mp;
	xfs_buf_t		*bp;
	struct xfs_disk_dquot	*ddq, *recddq;
	int			error;
	xfs_dq_logformat_t	*dq_f;
	uint			type;

	if (pass == XLOG_RECOVER_PASS1) {
		return 0;
	}
	mp = log->l_mp;

	/*
	 * Filesystems are required to send in quota flags at mount time.
	 */
	if (mp->m_qflags == 0)
		return (0);

	recddq = (xfs_disk_dquot_t *)item->ri_buf[1].i_addr;
	ASSERT(recddq);
	/*
	 * This type of quotas was turned off, so ignore this record.
	 */
	type = INT_GET(recddq->d_flags, ARCH_CONVERT) &
			(XFS_DQ_USER | XFS_DQ_GROUP);
	ASSERT(type);
	if (log->l_quotaoffs_flag & type)
		return (0);

	/*
	 * At this point we know that quota was _not_ turned off.
	 * Since the mount flags are not indicating to us otherwise, this
	 * must mean that quota is on, and the dquot needs to be replayed.
	 * Remember that we may not have fully recovered the superblock yet,
	 * so we can't do the usual trick of looking at the SB quota bits.
	 *
	 * The other possibility, of course, is that the quota subsystem was
	 * removed since the last mount - ENOSYS.
	 */
	dq_f = (xfs_dq_logformat_t *)item->ri_buf[0].i_addr;
	ASSERT(dq_f);
	if ((error = xfs_qm_dqcheck(recddq,
			   dq_f->qlf_id,
			   0, XFS_QMOPT_DOWARN,
			   "xlog_recover_do_dquot_trans (log copy)"))) {
		return XFS_ERROR(EIO);
	}
	ASSERT(dq_f->qlf_len == 1);

	error = xfs_read_buf(mp, mp->m_ddev_targp,
			     dq_f->qlf_blkno,
			     XFS_FSB_TO_BB(mp, dq_f->qlf_len),
			     0, &bp);
	if (error) {
		xfs_ioerror_alert("xlog_recover_do..(read#3)", mp,
				  bp, dq_f->qlf_blkno);
		return error;
	}
	ASSERT(bp);
	ddq = (xfs_disk_dquot_t *)xfs_buf_offset(bp, dq_f->qlf_boffset);

	/*
	 * At least the magic num portion should be on disk because this
	 * was among a chunk of dquots created earlier, and we did some
	 * minimal initialization then.
	 */
	if (xfs_qm_dqcheck(ddq, dq_f->qlf_id, 0, XFS_QMOPT_DOWARN,
			   "xlog_recover_do_dquot_trans")) {
		xfs_buf_relse(bp);
		return XFS_ERROR(EIO);
	}

	memcpy(ddq, recddq, item->ri_buf[1].i_len);

	ASSERT(dq_f->qlf_size == 2);
	ASSERT(XFS_BUF_FSPRIVATE(bp, void *) == NULL ||
	       XFS_BUF_FSPRIVATE(bp, xfs_mount_t *) == mp);
	XFS_BUF_SET_FSPRIVATE(bp, mp);
	XFS_BUF_SET_IODONE_FUNC(bp, xlog_recover_iodone);
	xfs_bdwrite(mp, bp);

	return (0);
}	/* xlog_recover_do_dquot_trans */

/*
 * This routine is called to create an in-core extent free intent
 * item from the efi format structure which was logged on disk.
 * It allocates an in-core efi, copies the extents from the format
 * structure into it, and adds the efi to the AIL with the given
 * LSN.
 */
STATIC void
xlog_recover_do_efi_trans(xlog_t		*log,
			  xlog_recover_item_t	*item,
			  xfs_lsn_t		lsn,
			  int			pass)
{
	xfs_mount_t		*mp;
	xfs_efi_log_item_t	*efip;
	xfs_efi_log_format_t	*efi_formatp;
	SPLDECL(s);

	if (pass == XLOG_RECOVER_PASS1) {
		return;
	}

	efi_formatp = (xfs_efi_log_format_t *)item->ri_buf[0].i_addr;
	ASSERT(item->ri_buf[0].i_len ==
	       (sizeof(xfs_efi_log_format_t) +
		((efi_formatp->efi_nextents - 1) * sizeof(xfs_extent_t))));

	mp = log->l_mp;
	efip = xfs_efi_init(mp, efi_formatp->efi_nextents);
	memcpy((char *)&(efip->efi_format), (char *)efi_formatp,
	      sizeof(xfs_efi_log_format_t) +
	      ((efi_formatp->efi_nextents - 1) * sizeof(xfs_extent_t)));
	efip->efi_next_extent = efi_formatp->efi_nextents;
	efip->efi_flags |= XFS_EFI_COMMITTED;

	AIL_LOCK(mp,s);
	/*
	 * xfs_trans_update_ail() drops the AIL lock.
	 */
	xfs_trans_update_ail(mp, (xfs_log_item_t *)efip, lsn, s);
}	/* xlog_recover_do_efi_trans */


/*
 * This routine is called when an efd format structure is found in
 * a committed transaction in the log.  It's purpose is to cancel
 * the corresponding efi if it was still in the log.  To do this
 * it searches the AIL for the efi with an id equal to that in the
 * efd format structure.  If we find it, we remove the efi from the
 * AIL and free it.
 */
STATIC void
xlog_recover_do_efd_trans(xlog_t		*log,
			  xlog_recover_item_t	*item,
			  int			pass)
{
	xfs_mount_t		*mp;
	xfs_efd_log_format_t	*efd_formatp;
	xfs_efi_log_item_t	*efip=NULL;
	xfs_log_item_t		*lip;
	int			gen;
	int			nexts;
	__uint64_t		efi_id;
	SPLDECL(s);

	if (pass == XLOG_RECOVER_PASS1) {
		return;
	}

	efd_formatp = (xfs_efd_log_format_t *)item->ri_buf[0].i_addr;
	ASSERT(item->ri_buf[0].i_len ==
	       (sizeof(xfs_efd_log_format_t) +
		((efd_formatp->efd_nextents - 1) * sizeof(xfs_extent_t))));
	efi_id = efd_formatp->efd_efi_id;

	/*
	 * Search for the efi with the id in the efd format structure
	 * in the AIL.
	 */
	mp = log->l_mp;
	AIL_LOCK(mp,s);
	lip = xfs_trans_first_ail(mp, &gen);
	while (lip != NULL) {
		if (lip->li_type == XFS_LI_EFI) {
			efip = (xfs_efi_log_item_t *)lip;
			if (efip->efi_format.efi_id == efi_id) {
				/*
				 * xfs_trans_delete_ail() drops the
				 * AIL lock.
				 */
				xfs_trans_delete_ail(mp, lip, s);
				break;
			}
		}
		lip = xfs_trans_next_ail(mp, lip, &gen, NULL);
	}
	if (lip == NULL) {
		AIL_UNLOCK(mp, s);
	}

	/*
	 * If we found it, then free it up.  If it wasn't there, it
	 * must have been overwritten in the log.  Oh well.
	 */
	if (lip != NULL) {
		nexts = efip->efi_format.efi_nextents;
		if (nexts > XFS_EFI_MAX_FAST_EXTENTS) {
			kmem_free(lip, sizeof(xfs_efi_log_item_t) +
				  ((nexts - 1) * sizeof(xfs_extent_t)));
		} else {
			kmem_zone_free(xfs_efi_zone, efip);
	}
	}
}	/* xlog_recover_do_efd_trans */

/*
 * Perform the transaction
 *
 * If the transaction modifies a buffer or inode, do it now.  Otherwise,
 * EFIs and EFDs get queued up by adding entries into the AIL for them.
 */
STATIC int
xlog_recover_do_trans(xlog_t	     *log,
		      xlog_recover_t *trans,
		      int	     pass)
{
	int		    error = 0;
	xlog_recover_item_t *item, *first_item;

	if ((error = xlog_recover_reorder_trans(log, trans)))
		return error;
	first_item = item = trans->r_itemq;
	do {
		/*
		 * we don't need to worry about the block number being
		 * truncated in > 1 TB buffers because in user-land,
		 * we're now n32 or 64-bit so xfs_daddr_t is 64-bits so
		 * the blkno's will get through the user-mode buffer
		 * cache properly.  The only bad case is o32 kernels
		 * where xfs_daddr_t is 32-bits but mount will warn us
		 * off a > 1 TB filesystem before we get here.
		 */
		if ((ITEM_TYPE(item) == XFS_LI_BUF) ||
		    (ITEM_TYPE(item) == XFS_LI_6_1_BUF) ||
		    (ITEM_TYPE(item) == XFS_LI_5_3_BUF)) {
			if  ((error = xlog_recover_do_buffer_trans(log, item,
								 pass)))
				break;
		} else if ((ITEM_TYPE(item) == XFS_LI_INODE) ||
			   (ITEM_TYPE(item) == XFS_LI_6_1_INODE) ||
			   (ITEM_TYPE(item) == XFS_LI_5_3_INODE)) {
			if ((error = xlog_recover_do_inode_trans(log, item,
								pass)))
				break;
		} else if (ITEM_TYPE(item) == XFS_LI_EFI) {
			xlog_recover_do_efi_trans(log, item, trans->r_lsn,
						  pass);
		} else if (ITEM_TYPE(item) == XFS_LI_EFD) {
			xlog_recover_do_efd_trans(log, item, pass);
		} else if (ITEM_TYPE(item) == XFS_LI_DQUOT) {
			if ((error = xlog_recover_do_dquot_trans(log, item,
								   pass)))
					break;
		} else if ((ITEM_TYPE(item) == XFS_LI_QUOTAOFF)) {
			if ((error = xlog_recover_do_quotaoff_trans(log, item,
								   pass)))
					break;
		} else {
			xlog_warn("XFS: xlog_recover_do_trans");
			ASSERT(0);
			error = XFS_ERROR(EIO);
			break;
		}
		item = item->ri_next;
	} while (first_item != item);

	return error;
}	/* xlog_recover_do_trans */


/*
 * Free up any resources allocated by the transaction
 *
 * Remember that EFIs, EFDs, and IUNLINKs are handled later.
 */
STATIC void
xlog_recover_free_trans(xlog_recover_t      *trans)
{
	xlog_recover_item_t *first_item, *item, *free_item;
	int i;

	item = first_item = trans->r_itemq;
	do {
		free_item = item;
		item = item->ri_next;
		 /* Free the regions in the item. */
		for (i = 0; i < free_item->ri_cnt; i++) {
			kmem_free(free_item->ri_buf[i].i_addr,
				  free_item->ri_buf[i].i_len);
		}
		/* Free the item itself */
		kmem_free(free_item->ri_buf,
			  (free_item->ri_total * sizeof(xfs_log_iovec_t)));
		kmem_free(free_item, sizeof(xlog_recover_item_t));
	} while (first_item != item);
	/* Free the transaction recover structure */
	kmem_free(trans, sizeof(xlog_recover_t));
}	/* xlog_recover_free_trans */


STATIC int
xlog_recover_commit_trans(xlog_t	 *log,
			  xlog_recover_t **q,
			  xlog_recover_t *trans,
			  int		 pass)
{
	int error;

	if ((error = xlog_recover_unlink_tid(q, trans)))
		return error;
	if ((error = xlog_recover_do_trans(log, trans, pass)))
		return error;
	xlog_recover_free_trans(trans);			/* no error */
	return 0;
}	/* xlog_recover_commit_trans */


/*ARGSUSED*/
STATIC int
xlog_recover_unmount_trans(xlog_recover_t *trans)
{
	/* Do nothing now */
	xlog_warn("XFS: xlog_recover_unmount_trans: Unmount LR");
	return( 0 );
}	/* xlog_recover_unmount_trans */


/*
 * There are two valid states of the r_state field.  0 indicates that the
 * transaction structure is in a normal state.  We have either seen the
 * start of the transaction or the last operation we added was not a partial
 * operation.  If the last operation we added to the transaction was a
 * partial operation, we need to mark r_state with XLOG_WAS_CONT_TRANS.
 *
 * NOTE: skip LRs with 0 data length.
 */
STATIC int
xlog_recover_process_data(xlog_t	    *log,
			  xlog_recover_t    *rhash[],
			  xlog_rec_header_t *rhead,
			  xfs_caddr_t	    dp,
			  int		    pass)
{
    xfs_caddr_t		lp	   = dp+INT_GET(rhead->h_len, ARCH_CONVERT);
    int			num_logops = INT_GET(rhead->h_num_logops, ARCH_CONVERT);
    xlog_op_header_t	*ohead;
    xlog_recover_t	*trans;
    xlog_tid_t		tid;
    int			error;
    unsigned long	hash;
    uint		flags;

    /* check the log format matches our own - else we can't recover */
    if (xlog_header_check_recover(log->l_mp, rhead))
	    return (XFS_ERROR(EIO));

    while ((dp < lp) && num_logops) {
	ASSERT(dp + sizeof(xlog_op_header_t) <= lp);
	ohead = (xlog_op_header_t *)dp;
	dp += sizeof(xlog_op_header_t);
	if (ohead->oh_clientid != XFS_TRANSACTION &&
	    ohead->oh_clientid != XFS_LOG) {
	    xlog_warn("XFS: xlog_recover_process_data: bad clientid");
	    ASSERT(0);
	    return (XFS_ERROR(EIO));
	}
	tid = INT_GET(ohead->oh_tid, ARCH_CONVERT);
	hash = XLOG_RHASH(tid);
	trans = xlog_recover_find_tid(rhash[hash], tid);
	if (trans == NULL) {			   /* not found; add new tid */
	    if (ohead->oh_flags & XLOG_START_TRANS)
		xlog_recover_new_tid(&rhash[hash], tid, INT_GET(rhead->h_lsn, ARCH_CONVERT));
	} else {
	    ASSERT(dp+INT_GET(ohead->oh_len, ARCH_CONVERT) <= lp);
	    flags = ohead->oh_flags & ~XLOG_END_TRANS;
	    if (flags & XLOG_WAS_CONT_TRANS)
		flags &= ~XLOG_CONTINUE_TRANS;
	    switch (flags) {
		case XLOG_COMMIT_TRANS: {
		    error = xlog_recover_commit_trans(log, &rhash[hash],
						      trans, pass);
		    break;
		}
		case XLOG_UNMOUNT_TRANS: {
		    error = xlog_recover_unmount_trans(trans);
		    break;
		}
		case XLOG_WAS_CONT_TRANS: {
		    error = xlog_recover_add_to_cont_trans(trans, dp,
				  INT_GET(ohead->oh_len, ARCH_CONVERT));
		    break;
		}
		case XLOG_START_TRANS : {
		    xlog_warn("XFS: xlog_recover_process_data: bad transaction");
		    ASSERT(0);
		    error = XFS_ERROR(EIO);
		    break;
		}
		case 0:
		case XLOG_CONTINUE_TRANS: {
		    error = xlog_recover_add_to_trans(trans, dp,
				   INT_GET(ohead->oh_len, ARCH_CONVERT));
		    break;
		}
		default: {
		    xlog_warn("XFS: xlog_recover_process_data: bad flag");
		    ASSERT(0);
		    error = XFS_ERROR(EIO);
		    break;
		}
	    } /* switch */
	    if (error)
		return error;
	} /* if */
	dp += INT_GET(ohead->oh_len, ARCH_CONVERT);
	num_logops--;
    }
    return( 0 );
}	/* xlog_recover_process_data */


/*
 * Process an extent free intent item that was recovered from
 * the log.  We need to free the extents that it describes.
 */
STATIC void
xlog_recover_process_efi(xfs_mount_t		*mp,
			 xfs_efi_log_item_t	*efip)
{
	xfs_efd_log_item_t	*efdp;
	xfs_trans_t		*tp;
	int			i;
	xfs_extent_t		*extp;
	xfs_fsblock_t		startblock_fsb;

	ASSERT(!(efip->efi_flags & XFS_EFI_RECOVERED));

	/*
	 * First check the validity of the extents described by the
	 * EFI.  If any are bad, then assume that all are bad and
	 * just toss the EFI.
	 */
	for (i = 0; i < efip->efi_format.efi_nextents; i++) {
		extp = &(efip->efi_format.efi_extents[i]);
		startblock_fsb = XFS_BB_TO_FSB(mp,
				   XFS_FSB_TO_DADDR(mp, extp->ext_start));
		if ((startblock_fsb == 0) ||
		    (extp->ext_len == 0) ||
		    (startblock_fsb >= mp->m_sb.sb_dblocks) ||
		    (extp->ext_len >= mp->m_sb.sb_agblocks)) {
			/*
			 * This will pull the EFI from the AIL and
			 * free the memory associated with it.
			 */
			xfs_efi_release(efip, efip->efi_format.efi_nextents);
			return;
		}
	}

	tp = xfs_trans_alloc(mp, 0);
	xfs_trans_reserve(tp, 0, XFS_ITRUNCATE_LOG_RES(mp), 0, 0, 0);
	efdp = xfs_trans_get_efd(tp, efip, efip->efi_format.efi_nextents);

	for (i = 0; i < efip->efi_format.efi_nextents; i++) {
		extp = &(efip->efi_format.efi_extents[i]);
		xfs_free_extent(tp, extp->ext_start, extp->ext_len);
		xfs_trans_log_efd_extent(tp, efdp, extp->ext_start,
					 extp->ext_len);
	}

	efip->efi_flags |= XFS_EFI_RECOVERED;
	xfs_trans_commit(tp, 0, NULL);
}	/* xlog_recover_process_efi */


/*
 * Verify that once we've encountered something other than an EFI
 * in the AIL that there are no more EFIs in the AIL.
 */
#if defined(DEBUG)
STATIC void
xlog_recover_check_ail(xfs_mount_t	*mp,
		       xfs_log_item_t	*lip,
		       int		gen)
{
	int	orig_gen;

	orig_gen = gen;
	do {
		ASSERT(lip->li_type != XFS_LI_EFI);
		lip = xfs_trans_next_ail(mp, lip, &gen, NULL);
		/*
		 * The check will be bogus if we restart from the
		 * beginning of the AIL, so ASSERT that we don't.
		 * We never should since we're holding the AIL lock
		 * the entire time.
		 */
		ASSERT(gen == orig_gen);
	} while (lip != NULL);
}
#endif	/* DEBUG */


/*
 * When this is called, all of the EFIs which did not have
 * corresponding EFDs should be in the AIL.  What we do now
 * is free the extents associated with each one.
 *
 * Since we process the EFIs in normal transactions, they
 * will be removed at some point after the commit.  This prevents
 * us from just walking down the list processing each one.
 * We'll use a flag in the EFI to skip those that we've already
 * processed and use the AIL iteration mechanism's generation
 * count to try to speed this up at least a bit.
 *
 * When we start, we know that the EFIs are the only things in
 * the AIL.  As we process them, however, other items are added
 * to the AIL.  Since everything added to the AIL must come after
 * everything already in the AIL, we stop processing as soon as
 * we see something other than an EFI in the AIL.
 */
STATIC void
xlog_recover_process_efis(xlog_t	*log)
{
	xfs_log_item_t		*lip;
	xfs_efi_log_item_t	*efip;
	int			gen;
	xfs_mount_t		*mp;
	SPLDECL(s);

	mp = log->l_mp;
	AIL_LOCK(mp,s);

	lip = xfs_trans_first_ail(mp, &gen);
	while (lip != NULL) {
		/*
		 * We're done when we see something other than an EFI.
		 */
		if (lip->li_type != XFS_LI_EFI) {
			xlog_recover_check_ail(mp, lip, gen);
			break;
		}

		/*
		 * Skip EFIs that we've already processed.
		 */
		efip = (xfs_efi_log_item_t *)lip;
		if (efip->efi_flags & XFS_EFI_RECOVERED) {
			lip = xfs_trans_next_ail(mp, lip, &gen, NULL);
			continue;
		}

		AIL_UNLOCK(mp, s);
		xlog_recover_process_efi(mp, efip);
		AIL_LOCK(mp,s);
		lip = xfs_trans_next_ail(mp, lip, &gen, NULL);
	}
	AIL_UNLOCK(mp, s);
}	/* xlog_recover_process_efis */


/*
 * This routine performs a transaction to null out a bad inode pointer
 * in an agi unlinked inode hash bucket.
 */
STATIC void
xlog_recover_clear_agi_bucket(
	xfs_mount_t	*mp,
	xfs_agnumber_t	agno,
	int		bucket)
{
	xfs_trans_t	*tp;
	xfs_agi_t	*agi;
	xfs_buf_t	*agibp;
	int		offset;
	int		error;

	tp = xfs_trans_alloc(mp, XFS_TRANS_CLEAR_AGI_BUCKET);
	xfs_trans_reserve(tp, 0, XFS_CLEAR_AGI_BUCKET_LOG_RES(mp), 0, 0, 0);

	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
				   XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
				   XFS_FSS_TO_BB(mp, 1), 0, &agibp);
	if (error) {
		xfs_trans_cancel(tp, XFS_TRANS_ABORT);
		return;
	}

	agi = XFS_BUF_TO_AGI(agibp);
	if (INT_GET(agi->agi_magicnum, ARCH_CONVERT) != XFS_AGI_MAGIC) {
		xfs_trans_cancel(tp, XFS_TRANS_ABORT);
		return;
	}
	ASSERT(INT_GET(agi->agi_magicnum, ARCH_CONVERT) == XFS_AGI_MAGIC);

	INT_SET(agi->agi_unlinked[bucket], ARCH_CONVERT, NULLAGINO);
	offset = offsetof(xfs_agi_t, agi_unlinked) +
		 (sizeof(xfs_agino_t) * bucket);
	xfs_trans_log_buf(tp, agibp, offset,
			  (offset + sizeof(xfs_agino_t) - 1));

	(void) xfs_trans_commit(tp, 0, NULL);
}	/* xlog_recover_clear_agi_bucket */


/*
 * xlog_iunlink_recover
 *
 * This is called during recovery to process any inodes which
 * we unlinked but not freed when the system crashed.  These
 * inodes will be on the lists in the AGI blocks.  What we do
 * here is scan all the AGIs and fully truncate and free any
 * inodes found on the lists.  Each inode is removed from the
 * lists when it has been fully truncated and is freed.  The
 * freeing of the inode and its removal from the list must be
 * atomic.
 */
void
xlog_recover_process_iunlinks(xlog_t	*log)
{
	xfs_mount_t	*mp;
	xfs_agnumber_t	agno;
	xfs_agi_t	*agi;
	xfs_buf_t	*agibp;
	xfs_buf_t	*ibp;
	xfs_dinode_t	*dip;
	xfs_inode_t	*ip;
	xfs_agino_t	agino;
	xfs_ino_t	ino;
	int		bucket;
	int		error;
	uint		mp_dmevmask;

	mp = log->l_mp;

	/*
	 * Prevent any DMAPI event from being sent while in this function.
	 */
	mp_dmevmask = mp->m_dmevmask;
	mp->m_dmevmask = 0;

	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
		/*
		 * Find the agi for this ag.
		 */
		agibp = xfs_buf_read(mp->m_ddev_targp,
				XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
				XFS_FSS_TO_BB(mp, 1), 0);
		if (XFS_BUF_ISERROR(agibp)) {
			xfs_ioerror_alert("xlog_recover_process_iunlinks(#1)",
				log->l_mp, agibp,
				XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)));
		}
		agi = XFS_BUF_TO_AGI(agibp);
		ASSERT(XFS_AGI_MAGIC ==
			INT_GET(agi->agi_magicnum, ARCH_CONVERT));

		for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++) {

			agino = INT_GET(agi->agi_unlinked[bucket], ARCH_CONVERT);
			while (agino != NULLAGINO) {

				/*
				 * Release the agi buffer so that it can
				 * be acquired in the normal course of the
				 * transaction to truncate and free the inode.
				 */
				xfs_buf_relse(agibp);

				ino = XFS_AGINO_TO_INO(mp, agno, agino);
				error = xfs_iget(mp, NULL, ino, 0, &ip, 0);
				ASSERT(error || (ip != NULL));

				if (!error) {
					/*
					 * Get the on disk inode to find the
					 * next inode in the bucket.
					 */
					error = xfs_itobp(mp, NULL, ip, &dip,
							&ibp, 0);
					ASSERT(error || (dip != NULL));
				}

				if (!error) {
					ASSERT(ip->i_d.di_nlink == 0);

					/* setup for the next pass */
					agino = INT_GET(dip->di_next_unlinked,
							ARCH_CONVERT);
					xfs_buf_relse(ibp);
					/*
					 * Prevent any DMAPI event from
					 * being sent when the
					 * reference on the inode is
					 * dropped.
					 */
					ip->i_d.di_dmevmask = 0;

					/*
					 * If this is a new inode, handle
					 * it specially.  Otherwise,
					 * just drop our reference to the
					 * inode.  If there are no
					 * other references, this will
					 * send the inode to
					 * xfs_inactive() which will
					 * truncate the file and free
					 * the inode.
					 */
					if (ip->i_d.di_mode == 0)
						xfs_iput_new(ip, 0);
					else
						VN_RELE(XFS_ITOV(ip));
				} else {
					/*
					 * We can't read in the inode
					 * this bucket points to, or
					 * this inode is messed up.  Just
					 * ditch this bucket of inodes.  We
					 * will lose some inodes and space,
					 * but at least we won't hang.  Call
					 * xlog_recover_clear_agi_bucket()
					 * to perform a transaction to clear
					 * the inode pointer in the bucket.
					 */
					xlog_recover_clear_agi_bucket(mp, agno,
							bucket);

					agino = NULLAGINO;
				}

				/*
				 * Reacquire the agibuffer and continue around
				 * the loop.
				 */
				agibp = xfs_buf_read(mp->m_ddev_targp,
						XFS_AG_DADDR(mp, agno,
							XFS_AGI_DADDR(mp)),
						XFS_FSS_TO_BB(mp, 1), 0);
				if (XFS_BUF_ISERROR(agibp)) {
					xfs_ioerror_alert(
				"xlog_recover_process_iunlinks(#2)",
						log->l_mp, agibp,
						XFS_AG_DADDR(mp, agno,
							XFS_AGI_DADDR(mp)));
				}
				agi = XFS_BUF_TO_AGI(agibp);
				ASSERT(XFS_AGI_MAGIC == INT_GET(
					agi->agi_magicnum, ARCH_CONVERT));
			}
		}

		/*
		 * Release the buffer for the current agi so we can
		 * go on to the next one.
		 */
		xfs_buf_relse(agibp);
	}

	mp->m_dmevmask = mp_dmevmask;

}	/* xlog_recover_process_iunlinks */


/*
 * Stamp cycle number in every block
 *
 * This routine is also called in xfs_log.c
 */
/*ARGSUSED*/
void
xlog_pack_data(xlog_t *log, xlog_in_core_t *iclog)
{
	int	i, j, k;
	int	size = iclog->ic_offset + iclog->ic_roundoff;
	xfs_caddr_t dp;
	union ich {
		xlog_rec_ext_header_t	hic_xheader;
		char			hic_sector[XLOG_HEADER_SIZE];
	} *xhdr;
	uint	cycle_lsn;

#ifdef DEBUG
	uint	*up;
	uint	chksum = 0;

	up = (uint *)iclog->ic_datap;
	/* divide length by 4 to get # words */
	for (i=0; i<size >> 2; i++) {
		chksum ^= INT_GET(*up, ARCH_CONVERT);
		up++;
	}
	INT_SET(iclog->ic_header.h_chksum, ARCH_CONVERT, chksum);
#endif /* DEBUG */

	cycle_lsn = CYCLE_LSN_NOCONV(iclog->ic_header.h_lsn, ARCH_CONVERT);

	dp = iclog->ic_datap;
	for (i = 0; i < BTOBB(size) &&
		i < (XLOG_HEADER_CYCLE_SIZE / BBSIZE); i++) {
		iclog->ic_header.h_cycle_data[i] = *(uint *)dp;
		*(uint *)dp = cycle_lsn;
		dp += BBSIZE;
	}

	if (XFS_SB_VERSION_HASLOGV2(&log->l_mp->m_sb)) {
		xhdr = (union ich*)&iclog->ic_header;
		for ( ; i < BTOBB(size); i++) {
			j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
			k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
			xhdr[j].hic_xheader.xh_cycle_data[k] = *(uint *)dp;
			*(uint *)dp = cycle_lsn;
			dp += BBSIZE;
		}

		for (i = 1; i < log->l_iclog_heads; i++) {
			xhdr[i].hic_xheader.xh_cycle = cycle_lsn;
		}
	}

}	/* xlog_pack_data */


/*ARGSUSED*/
STATIC void
xlog_unpack_data(xlog_rec_header_t *rhead,
		 xfs_caddr_t	   dp,
		 xlog_t		   *log)
{
	int i, j, k;
	union ich {
		xlog_rec_header_t	hic_header;
		xlog_rec_ext_header_t	hic_xheader;
		char			hic_sector[XLOG_HEADER_SIZE];
	} *xhdr;

#if defined(DEBUG) && defined(XFS_LOUD_RECOVERY)
	uint *up = (uint *)dp;
	uint chksum = 0;
#endif

	for (i=0; i < BTOBB(INT_GET(rhead->h_len, ARCH_CONVERT)) &&
		  i < (XLOG_HEADER_CYCLE_SIZE / BBSIZE); i++) {
		*(uint *)dp = *(uint *)&rhead->h_cycle_data[i];
		dp += BBSIZE;
	}

	if (XFS_SB_VERSION_HASLOGV2(&log->l_mp->m_sb)) {
		xhdr = (union ich*)rhead;
		for ( ; i < BTOBB(INT_GET(rhead->h_len, ARCH_CONVERT)); i++) {
			j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
			k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
			*(uint *)dp = xhdr[j].hic_xheader.xh_cycle_data[k];
			dp += BBSIZE;
		}
	}

#if defined(DEBUG) && defined(XFS_LOUD_RECOVERY)
	/* divide length by 4 to get # words */
	for (i=0; i < INT_GET(rhead->h_len, ARCH_CONVERT) >> 2; i++) {
		chksum ^= INT_GET(*up, ARCH_CONVERT);
		up++;
	}
	if (chksum != INT_GET(rhead->h_chksum, ARCH_CONVERT)) {
	    if (!INT_ISZERO(rhead->h_chksum, ARCH_CONVERT) ||
		((log->l_flags & XLOG_CHKSUM_MISMATCH) == 0)) {
		    cmn_err(CE_DEBUG,
			"XFS: LogR chksum mismatch: was (0x%x) is (0x%x)",
			    INT_GET(rhead->h_chksum, ARCH_CONVERT), chksum);
		    cmn_err(CE_DEBUG,
"XFS: Disregard message if filesystem was created with non-DEBUG kernel");
		    if (XFS_SB_VERSION_HASLOGV2(&log->l_mp->m_sb)) {
			    cmn_err(CE_DEBUG,
				"XFS: LogR this is a LogV2 filesystem");
		    }
		    log->l_flags |= XLOG_CHKSUM_MISMATCH;
	    }
	}
#endif /* DEBUG && XFS_LOUD_RECOVERY */
}	/* xlog_unpack_data */


/*
 * Read the log from tail to head and process the log records found.
 * Handle the two cases where the tail and head are in the same cycle
 * and where the active portion of the log wraps around the end of
 * the physical log separately.  The pass parameter is passed through
 * to the routines called to process the data and is not looked at
 * here.
 */
STATIC int
xlog_do_recovery_pass(xlog_t	*log,
		      xfs_daddr_t	head_blk,
		      xfs_daddr_t	tail_blk,
		      int	pass)
{
    xlog_rec_header_t	*rhead;
    xfs_daddr_t		blk_no;
    xfs_caddr_t		bufaddr;
    xfs_buf_t		*hbp, *dbp;
    int			error, h_size;
    int			bblks, split_bblks;
    int			hblks, split_hblks, wrapped_hblks;
    xlog_recover_t	*rhash[XLOG_RHASH_SIZE];

    error = 0;


    /*
     * Read the header of the tail block and get the iclog buffer size from
     * h_size.  Use this to tell how many sectors make up the log header.
     */
    if (XFS_SB_VERSION_HASLOGV2(&log->l_mp->m_sb)) {
	/*
	 * When using variable length iclogs, read first sector of iclog
	 * header and extract the header size from it.  Get a new hbp that
	 * is the correct size.
	 */
	hbp = xlog_get_bp(1, log->l_mp);
	if (!hbp)
	    return ENOMEM;
	if ((error = xlog_bread(log, tail_blk, 1, hbp)))
	    goto bread_err1;
	rhead = (xlog_rec_header_t *)XFS_BUF_PTR(hbp);
	ASSERT(INT_GET(rhead->h_magicno, ARCH_CONVERT) ==
						XLOG_HEADER_MAGIC_NUM);
	if ((INT_GET(rhead->h_version, ARCH_CONVERT) & (~XLOG_VERSION_OKBITS)) != 0) {
	    xlog_warn("XFS: xlog_do_recovery_pass: unrecognised log version number.");
	    error = XFS_ERROR(EIO);
	    goto bread_err1;
	}
	h_size = INT_GET(rhead->h_size, ARCH_CONVERT);

	if ((INT_GET(rhead->h_version, ARCH_CONVERT) & XLOG_VERSION_2) &&
	    (h_size > XLOG_HEADER_CYCLE_SIZE)) {
	    hblks = h_size / XLOG_HEADER_CYCLE_SIZE;
	    if (h_size % XLOG_HEADER_CYCLE_SIZE)
		hblks++;
	    xlog_put_bp(hbp);
	    hbp = xlog_get_bp(hblks, log->l_mp);
	} else {
	    hblks=1;
	}
    } else {
	hblks=1;
	hbp = xlog_get_bp(1, log->l_mp);
	h_size = XLOG_BIG_RECORD_BSIZE;
    }

    if (!hbp)
	return ENOMEM;
    dbp = xlog_get_bp(BTOBB(h_size),log->l_mp);
    if (!dbp) {
	xlog_put_bp(hbp);
	return ENOMEM;
    }

    memset(rhash, 0, sizeof(rhash));
    if (tail_blk <= head_blk) {
	for (blk_no = tail_blk; blk_no < head_blk; ) {
	    if ((error = xlog_bread(log, blk_no, hblks, hbp)))
		goto bread_err2;
	    rhead = (xlog_rec_header_t *)XFS_BUF_PTR(hbp);
	    ASSERT(INT_GET(rhead->h_magicno, ARCH_CONVERT) == XLOG_HEADER_MAGIC_NUM);
	    ASSERT(BTOBB(INT_GET(rhead->h_len, ARCH_CONVERT) <= INT_MAX));
	    bblks = (int) BTOBB(INT_GET(rhead->h_len, ARCH_CONVERT));	/* blocks in data section */

	    if (unlikely((INT_GET(rhead->h_magicno, ARCH_CONVERT) != XLOG_HEADER_MAGIC_NUM) ||
		(BTOBB(INT_GET(rhead->h_len, ARCH_CONVERT) > INT_MAX)) ||
		(bblks <= 0) ||
		(blk_no > log->l_logBBsize))) {
		    XFS_ERROR_REPORT("xlog_do_recovery_pass(1)",
				     XFS_ERRLEVEL_LOW, log->l_mp);
		    error = EFSCORRUPTED;
		    goto bread_err2;
	    }

	    if ((INT_GET(rhead->h_version, ARCH_CONVERT) & (~XLOG_VERSION_OKBITS)) != 0) {
		xlog_warn("XFS: xlog_do_recovery_pass: unrecognised log version number.");
		error = XFS_ERROR(EIO);
		goto bread_err2;
	    }
	    bblks = (int) BTOBB(INT_GET(rhead->h_len, ARCH_CONVERT));	/* blocks in data section */
	    if (bblks > 0) {
		if ((error = xlog_bread(log, blk_no+hblks, bblks, dbp)))
		    goto bread_err2;
		xlog_unpack_data(rhead, XFS_BUF_PTR(dbp), log);
		if ((error = xlog_recover_process_data(log, rhash,
						      rhead, XFS_BUF_PTR(dbp),
						      pass)))
			goto bread_err2;
	    }
	    blk_no += (bblks+hblks);
	}
    } else {
	/*
	 * Perform recovery around the end of the physical log.  When the head
	 * is not on the same cycle number as the tail, we can't do a sequential
	 * recovery as above.
	 */
	blk_no = tail_blk;
	while (blk_no < log->l_logBBsize) {
	    /*
	     * Check for header wrapping around physical end-of-log
	     */
	    wrapped_hblks = 0;
	    if (blk_no+hblks <= log->l_logBBsize) {
		/* Read header in one read */
		if ((error = xlog_bread(log, blk_no, hblks, hbp)))
		    goto bread_err2;
	    } else {
		/* This log record is split across physical end of log */
		split_hblks = 0;
		if (blk_no != log->l_logBBsize) {
		    /* some data is before physical end of log */
		    ASSERT(blk_no <= INT_MAX);
		    split_hblks = log->l_logBBsize - (int)blk_no;
		    ASSERT(split_hblks > 0);
		    if ((error = xlog_bread(log, blk_no, split_hblks, hbp)))
			goto bread_err2;
		}
		bufaddr = XFS_BUF_PTR(hbp);
		XFS_BUF_SET_PTR(hbp, bufaddr + BBTOB(split_hblks),
			BBTOB(hblks - split_hblks));
		wrapped_hblks = hblks - split_hblks;
		if ((error = xlog_bread(log, 0, wrapped_hblks, hbp)))
		    goto bread_err2;
		XFS_BUF_SET_PTR(hbp, bufaddr, hblks);
	    }
	    rhead = (xlog_rec_header_t *)XFS_BUF_PTR(hbp);
	    ASSERT(INT_GET(rhead->h_magicno, ARCH_CONVERT) == XLOG_HEADER_MAGIC_NUM);
	    ASSERT(BTOBB(INT_GET(rhead->h_len, ARCH_CONVERT) <= INT_MAX));
	    bblks = (int) BTOBB(INT_GET(rhead->h_len, ARCH_CONVERT));

	    /* LR body must have data or it wouldn't have been written */
	    ASSERT(bblks > 0);
	    blk_no += hblks;			/* successfully read header */

	    if (unlikely((INT_GET(rhead->h_magicno, ARCH_CONVERT) != XLOG_HEADER_MAGIC_NUM) ||
		(BTOBB(INT_GET(rhead->h_len, ARCH_CONVERT) > INT_MAX)) ||
		(bblks <= 0))) {
		    XFS_ERROR_REPORT("xlog_do_recovery_pass(2)",
				     XFS_ERRLEVEL_LOW, log->l_mp);
		    error = EFSCORRUPTED;
		    goto bread_err2;
	    }

	    /* Read in data for log record */
	    if (blk_no+bblks <= log->l_logBBsize) {
		if ((error = xlog_bread(log, blk_no, bblks, dbp)))
		    goto bread_err2;
	    } else {
		/* This log record is split across physical end of log */
		split_bblks = 0;
		if (blk_no != log->l_logBBsize) {

		    /* some data is before physical end of log */
		    ASSERT(blk_no <= INT_MAX);
		    split_bblks = log->l_logBBsize - (int)blk_no;
		    ASSERT(split_bblks > 0);
		    if ((error = xlog_bread(log, blk_no, split_bblks, dbp)))
			goto bread_err2;
		}
		bufaddr = XFS_BUF_PTR(dbp);
		XFS_BUF_SET_PTR(dbp, bufaddr + BBTOB(split_bblks),
			BBTOB(bblks - split_bblks));
		if ((error = xlog_bread(log, wrapped_hblks,
					bblks - split_bblks, dbp)))
		    goto bread_err2;
		XFS_BUF_SET_PTR(dbp, bufaddr, XLOG_BIG_RECORD_BSIZE);
	    }
	    xlog_unpack_data(rhead, XFS_BUF_PTR(dbp), log);
	    if ((error = xlog_recover_process_data(log, rhash,
						  rhead, XFS_BUF_PTR(dbp),
						  pass)))
		goto bread_err2;
	    blk_no += bblks;
	}

	ASSERT(blk_no >= log->l_logBBsize);
	blk_no -= log->l_logBBsize;

	/* read first part of physical log */
	while (blk_no < head_blk) {
	    if ((error = xlog_bread(log, blk_no, hblks, hbp)))
		goto bread_err2;
	    rhead = (xlog_rec_header_t *)XFS_BUF_PTR(hbp);
	    ASSERT(INT_GET(rhead->h_magicno, ARCH_CONVERT) == XLOG_HEADER_MAGIC_NUM);
	    ASSERT(BTOBB(INT_GET(rhead->h_len, ARCH_CONVERT) <= INT_MAX));
	    bblks = (int) BTOBB(INT_GET(rhead->h_len, ARCH_CONVERT));
	    ASSERT(bblks > 0);
	    if ((error = xlog_bread(log, blk_no+hblks, bblks, dbp)))
		goto bread_err2;
	    xlog_unpack_data(rhead, XFS_BUF_PTR(dbp), log);
	    if ((error = xlog_recover_process_data(log, rhash,
						  rhead, XFS_BUF_PTR(dbp),
						  pass)))
		goto bread_err2;
	    blk_no += (bblks+hblks);
	}
    }

bread_err2:
    xlog_put_bp(dbp);
bread_err1:
    xlog_put_bp(hbp);

    return error;
}

/*
 * Do the recovery of the log.  We actually do this in two phases.
 * The two passes are necessary in order to implement the function
 * of cancelling a record written into the log.  The first pass
 * determines those things which have been cancelled, and the
 * second pass replays log items normally except for those which
 * have been cancelled.  The handling of the replay and cancellations
 * takes place in the log item type specific routines.
 *
 * The table of items which have cancel records in the log is allocated
 * and freed at this level, since only here do we know when all of
 * the log recovery has been completed.
 */
STATIC int
xlog_do_log_recovery(xlog_t	*log,
		     xfs_daddr_t	head_blk,
		     xfs_daddr_t	tail_blk)
{
	int		error;
#ifdef DEBUG
	int		i;
#endif

	/*
	 * First do a pass to find all of the cancelled buf log items.
	 * Store them in the buf_cancel_table for use in the second pass.
	 */
	log->l_buf_cancel_table =
		(xfs_buf_cancel_t **)kmem_zalloc(XLOG_BC_TABLE_SIZE *
						 sizeof(xfs_buf_cancel_t*),
						 KM_SLEEP);
	error = xlog_do_recovery_pass(log, head_blk, tail_blk,
				      XLOG_RECOVER_PASS1);
	if (error != 0) {
		kmem_free(log->l_buf_cancel_table,
			  XLOG_BC_TABLE_SIZE * sizeof(xfs_buf_cancel_t*));
		log->l_buf_cancel_table = NULL;
		return error;
	}
	/*
	 * Then do a second pass to actually recover the items in the log.
	 * When it is complete free the table of buf cancel items.
	 */
	error = xlog_do_recovery_pass(log, head_blk, tail_blk,
				      XLOG_RECOVER_PASS2);
#ifdef	DEBUG
	for (i = 0; i < XLOG_BC_TABLE_SIZE; i++) {
		ASSERT(log->l_buf_cancel_table[i] == NULL);
	}
#endif	/* DEBUG */
	kmem_free(log->l_buf_cancel_table,
		  XLOG_BC_TABLE_SIZE * sizeof(xfs_buf_cancel_t*));
	log->l_buf_cancel_table = NULL;

	return error;
}

/*
 * Do the actual recovery
 */
STATIC int
xlog_do_recover(xlog_t	*log,
		xfs_daddr_t head_blk,
		xfs_daddr_t tail_blk)
{
	int		error;
	xfs_buf_t	*bp;
	xfs_sb_t	*sbp;

	/*
	 * First replay the images in the log.
	 */
	error = xlog_do_log_recovery(log, head_blk, tail_blk);
	if (error) {
		return error;
	}

	XFS_bflush(log->l_mp->m_ddev_targp);

	/*
	 * If IO errors happened during recovery, bail out.
	 */
	if (XFS_FORCED_SHUTDOWN(log->l_mp)) {
		return (EIO);
	}

	/*
	 * We now update the tail_lsn since much of the recovery has completed
	 * and there may be space available to use.  If there were no extent
	 * or iunlinks, we can free up the entire log and set the tail_lsn to
	 * be the last_sync_lsn.  This was set in xlog_find_tail to be the
	 * lsn of the last known good LR on disk.  If there are extent frees
	 * or iunlinks they will have some entries in the AIL; so we look at
	 * the AIL to determine how to set the tail_lsn.
	 */
	xlog_assign_tail_lsn(log->l_mp);

	/*
	 * Now that we've finished replaying all buffer and inode
	 * updates, re-read in the superblock.
	 */
	bp = xfs_getsb(log->l_mp, 0);
	XFS_BUF_UNDONE(bp);
	XFS_BUF_READ(bp);
	xfsbdstrat(log->l_mp, bp);
	if ((error = xfs_iowait(bp))) {
		xfs_ioerror_alert("xlog_do_recover",
				  log->l_mp, bp, XFS_BUF_ADDR(bp));
		ASSERT(0);
		xfs_buf_relse(bp);
		return error;
	}

	/* Convert superblock from on-disk format */
	sbp = &log->l_mp->m_sb;
	xfs_xlatesb(XFS_BUF_TO_SBP(bp), sbp, 1, ARCH_CONVERT, XFS_SB_ALL_BITS);
	ASSERT(sbp->sb_magicnum == XFS_SB_MAGIC);
	ASSERT(XFS_SB_GOOD_VERSION(sbp));
	xfs_buf_relse(bp);

	xlog_recover_check_summary(log);

	/* Normal transactions can now occur */
	log->l_flags &= ~XLOG_ACTIVE_RECOVERY;
	return 0;
}	/* xlog_do_recover */

/*
 * Perform recovery and re-initialize some log variables in xlog_find_tail.
 *
 * Return error or zero.
 */
int
xlog_recover(xlog_t *log, int readonly)
{
	xfs_daddr_t head_blk, tail_blk;
	int	error;

	/* find the tail of the log */

	if ((error = xlog_find_tail(log, &head_blk, &tail_blk, readonly)))
		return error;

	if (tail_blk != head_blk) {
#ifndef __KERNEL__
		extern xfs_daddr_t HEAD_BLK, TAIL_BLK;
		head_blk = HEAD_BLK;
		tail_blk = TAIL_BLK;
#endif
		/* There used to be a comment here:
		 *
		 * disallow recovery on read-only mounts.  note -- mount
		 * checks for ENOSPC and turns it into an intelligent
		 * error message.
		 * ...but this is no longer true.  Now, unless you specify
		 * NORECOVERY (in which case this function would never be
		 * called), we just go ahead and recover.  We do this all
		 * under the vfs layer, so we can get away with it unless
		 * the device itself is read-only, in which case we fail.
		 */
#ifdef __KERNEL__
		if ((error = xfs_dev_is_read_only(log->l_mp,
						"recovery required"))) {
			return error;
		}
#else
		if (readonly) {
			return ENOSPC;
		}
#endif

#ifdef __KERNEL__
#if defined(DEBUG) && defined(XFS_LOUD_RECOVERY)
		cmn_err(CE_NOTE,
			"Starting XFS recovery on filesystem: %s (dev: %d/%d)",
			log->l_mp->m_fsname, MAJOR(log->l_dev),
			MINOR(log->l_dev));
#else
		cmn_err(CE_NOTE,
			"!Starting XFS recovery on filesystem: %s (dev: %d/%d)",
			log->l_mp->m_fsname, MAJOR(log->l_dev),
			MINOR(log->l_dev));
#endif
#endif
		error = xlog_do_recover(log, head_blk, tail_blk);
		log->l_flags |= XLOG_RECOVERY_NEEDED;
	}
	return error;
}	/* xlog_recover */


/*
 * In the first part of recovery we replay inodes and buffers and build
 * up the list of extent free items which need to be processed.  Here
 * we process the extent free items and clean up the on disk unlinked
 * inode lists.  This is separated from the first part of recovery so
 * that the root and real-time bitmap inodes can be read in from disk in
 * between the two stages.  This is necessary so that we can free space
 * in the real-time portion of the file system.
 */
int
xlog_recover_finish(xlog_t *log, int mfsi_flags)
{
	/*
	 * Now we're ready to do the transactions needed for the
	 * rest of recovery.  Start with completing all the extent
	 * free intent records and then process the unlinked inode
	 * lists.  At this point, we essentially run in normal mode
	 * except that we're still performing recovery actions
	 * rather than accepting new requests.
	 */
	if (log->l_flags & XLOG_RECOVERY_NEEDED) {
		xlog_recover_process_efis(log);
		/*
		 * Sync the log to get all the EFIs out of the AIL.
		 * This isn't absolutely necessary, but it helps in
		 * case the unlink transactions would have problems
		 * pushing the EFIs out of the way.
		 */
		xfs_log_force(log->l_mp, (xfs_lsn_t)0,
			      (XFS_LOG_FORCE | XFS_LOG_SYNC));

		if ( (mfsi_flags & XFS_MFSI_NOUNLINK) == 0 ) {

			xlog_recover_process_iunlinks(log);
		}

		xlog_recover_check_summary(log);

#if defined(DEBUG) && defined(XFS_LOUD_RECOVERY)
		cmn_err(CE_NOTE,
			"Ending XFS recovery on filesystem: %s (dev: %d/%d)",
			log->l_mp->m_fsname, MAJOR(log->l_dev),
			MINOR(log->l_dev));
#else
		cmn_err(CE_NOTE,
			"!Ending XFS recovery on filesystem: %s (dev: %d/%d)",
			log->l_mp->m_fsname, MAJOR(log->l_dev),
			MINOR(log->l_dev));
#endif
		log->l_flags &= ~XLOG_RECOVERY_NEEDED;
	} else {
		cmn_err(CE_DEBUG,
			"!Ending clean XFS mount for filesystem: %s",
			log->l_mp->m_fsname);
	}
	return 0;
}	/* xlog_recover_finish */


#if defined(DEBUG)
/*
 * Read all of the agf and agi counters and check that they
 * are consistent with the superblock counters.
 */
void
xlog_recover_check_summary(xlog_t	*log)
{
	xfs_mount_t	*mp;
	xfs_agf_t	*agfp;
	xfs_agi_t	*agip;
	xfs_buf_t	*agfbp;
	xfs_buf_t	*agibp;
	xfs_daddr_t	agfdaddr;
	xfs_daddr_t	agidaddr;
	xfs_buf_t	*sbbp;
#ifdef XFS_LOUD_RECOVERY
	xfs_sb_t	*sbp;
#endif
	xfs_agnumber_t	agno;
	__uint64_t	freeblks;
	__uint64_t	itotal;
	__uint64_t	ifree;

	mp = log->l_mp;

	freeblks = 0LL;
	itotal = 0LL;
	ifree = 0LL;
	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
		agfdaddr = XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp));
		agfbp = xfs_buf_read(mp->m_ddev_targp, agfdaddr,
				XFS_FSS_TO_BB(mp, 1), 0);
		if (XFS_BUF_ISERROR(agfbp)) {
			xfs_ioerror_alert("xlog_recover_check_summary(agf)",
						mp, agfbp, agfdaddr);
		}
		agfp = XFS_BUF_TO_AGF(agfbp);
		ASSERT(XFS_AGF_MAGIC ==
			INT_GET(agfp->agf_magicnum, ARCH_CONVERT));
		ASSERT(XFS_AGF_GOOD_VERSION(
			INT_GET(agfp->agf_versionnum, ARCH_CONVERT)));
		ASSERT(INT_GET(agfp->agf_seqno, ARCH_CONVERT) == agno);

		freeblks += INT_GET(agfp->agf_freeblks, ARCH_CONVERT) +
			    INT_GET(agfp->agf_flcount, ARCH_CONVERT);
		xfs_buf_relse(agfbp);

		agidaddr = XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp));
		agibp = xfs_buf_read(mp->m_ddev_targp, agidaddr,
				XFS_FSS_TO_BB(mp, 1), 0);
		if (XFS_BUF_ISERROR(agibp)) {
			xfs_ioerror_alert("xlog_recover_check_summary(agi)",
					  log->l_mp, agibp, agidaddr);
		}
		agip = XFS_BUF_TO_AGI(agibp);
		ASSERT(XFS_AGI_MAGIC ==
			INT_GET(agip->agi_magicnum, ARCH_CONVERT));
		ASSERT(XFS_AGI_GOOD_VERSION(
			INT_GET(agip->agi_versionnum, ARCH_CONVERT)));
		ASSERT(INT_GET(agip->agi_seqno, ARCH_CONVERT) == agno);

		itotal += INT_GET(agip->agi_count, ARCH_CONVERT);
		ifree += INT_GET(agip->agi_freecount, ARCH_CONVERT);
		xfs_buf_relse(agibp);
	}

	sbbp = xfs_getsb(mp, 0);
#ifdef XFS_LOUD_RECOVERY
	sbp = XFS_BUF_TO_SBP(sbbp);
	cmn_err(CE_NOTE,
		"xlog_recover_check_summary: sb_icount %Lu itotal %Lu",
		sbp->sb_icount, itotal);
	cmn_err(CE_NOTE,
		"xlog_recover_check_summary: sb_ifree %Lu itotal %Lu",
		sbp->sb_ifree, ifree);
	cmn_err(CE_NOTE,
		"xlog_recover_check_summary: sb_fdblocks %Lu freeblks %Lu",
		sbp->sb_fdblocks, freeblks);
#if 0
	/*
	 * This is turned off until I account for the allocation
	 * btree blocks which live in free space.
	 */
	ASSERT(sbp->sb_icount == itotal);
	ASSERT(sbp->sb_ifree == ifree);
	ASSERT(sbp->sb_fdblocks == freeblks);
#endif
#endif
	xfs_buf_relse(sbbp);
}
#endif /* DEBUG */
