patch-2.4.25 linux-2.4.25/fs/xfs/xfs_trans_buf.c

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diff -urN linux-2.4.24/fs/xfs/xfs_trans_buf.c linux-2.4.25/fs/xfs/xfs_trans_buf.c
@@ -0,0 +1,1128 @@
+/*
+ * 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_trans.h"
+#include "xfs_buf_item.h"
+#include "xfs_sb.h"
+#include "xfs_ag.h"
+#include "xfs_dir.h"
+#include "xfs_dmapi.h"
+#include "xfs_mount.h"
+#include "xfs_trans_priv.h"
+#include "xfs_error.h"
+#include "xfs_rw.h"
+
+
+STATIC xfs_buf_t *xfs_trans_buf_item_match(xfs_trans_t *, xfs_buftarg_t *,
+		xfs_daddr_t, int);
+STATIC xfs_buf_t *xfs_trans_buf_item_match_all(xfs_trans_t *, xfs_buftarg_t *,
+		xfs_daddr_t, int);
+
+
+/*
+ * Get and lock the buffer for the caller if it is not already
+ * locked within the given transaction.  If it is already locked
+ * within the transaction, just increment its lock recursion count
+ * and return a pointer to it.
+ *
+ * Use the fast path function xfs_trans_buf_item_match() or the buffer
+ * cache routine incore_match() to find the buffer
+ * if it is already owned by this transaction.
+ *
+ * If we don't already own the buffer, use get_buf() to get it.
+ * If it doesn't yet have an associated xfs_buf_log_item structure,
+ * then allocate one and add the item to this transaction.
+ *
+ * If the transaction pointer is NULL, make this just a normal
+ * get_buf() call.
+ */
+xfs_buf_t *
+xfs_trans_get_buf(xfs_trans_t	*tp,
+		  xfs_buftarg_t	*target_dev,
+		  xfs_daddr_t	blkno,
+		  int		len,
+		  uint		flags)
+{
+	xfs_buf_t		*bp;
+	xfs_buf_log_item_t	*bip;
+
+	if (flags == 0)
+		flags = XFS_BUF_LOCK | XFS_BUF_MAPPED;
+
+	/*
+	 * Default to a normal get_buf() call if the tp is NULL.
+	 */
+	if (tp == NULL) {
+		bp = xfs_buf_get_flags(target_dev, blkno, len,
+							flags | BUF_BUSY);
+		return(bp);
+	}
+
+	/*
+	 * If we find the buffer in the cache with this transaction
+	 * pointer in its b_fsprivate2 field, then we know we already
+	 * have it locked.  In this case we just increment the lock
+	 * recursion count and return the buffer to the caller.
+	 */
+	if (tp->t_items.lic_next == NULL) {
+		bp = xfs_trans_buf_item_match(tp, target_dev, blkno, len);
+	} else {
+		bp  = xfs_trans_buf_item_match_all(tp, target_dev, blkno, len);
+	}
+	if (bp != NULL) {
+		ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
+		if (XFS_FORCED_SHUTDOWN(tp->t_mountp)) {
+			xfs_buftrace("TRANS GET RECUR SHUT", bp);
+			XFS_BUF_SUPER_STALE(bp);
+		}
+		/*
+		 * If the buffer is stale then it was binval'ed
+		 * since last read.  This doesn't matter since the
+		 * caller isn't allowed to use the data anyway.
+		 */
+		else if (XFS_BUF_ISSTALE(bp)) {
+			xfs_buftrace("TRANS GET RECUR STALE", bp);
+			ASSERT(!XFS_BUF_ISDELAYWRITE(bp));
+		}
+		ASSERT(XFS_BUF_FSPRIVATE2(bp, xfs_trans_t *) == tp);
+		bip = XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t *);
+		ASSERT(bip != NULL);
+		ASSERT(atomic_read(&bip->bli_refcount) > 0);
+		bip->bli_recur++;
+		xfs_buftrace("TRANS GET RECUR", bp);
+		xfs_buf_item_trace("GET RECUR", bip);
+		return (bp);
+	}
+
+	/*
+	 * We always specify the BUF_BUSY flag within a transaction so
+	 * that get_buf does not try to push out a delayed write buffer
+	 * which might cause another transaction to take place (if the
+	 * buffer was delayed alloc).  Such recursive transactions can
+	 * easily deadlock with our current transaction as well as cause
+	 * us to run out of stack space.
+	 */
+	bp = xfs_buf_get_flags(target_dev, blkno, len, flags | BUF_BUSY);
+	if (bp == NULL) {
+		return NULL;
+	}
+
+	ASSERT(!XFS_BUF_GETERROR(bp));
+
+	/*
+	 * The xfs_buf_log_item pointer is stored in b_fsprivate.  If
+	 * it doesn't have one yet, then allocate one and initialize it.
+	 * The checks to see if one is there are in xfs_buf_item_init().
+	 */
+	xfs_buf_item_init(bp, tp->t_mountp);
+
+	/*
+	 * Set the recursion count for the buffer within this transaction
+	 * to 0.
+	 */
+	bip = XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t*);
+	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
+	ASSERT(!(bip->bli_format.blf_flags & XFS_BLI_CANCEL));
+	ASSERT(!(bip->bli_flags & XFS_BLI_LOGGED));
+	bip->bli_recur = 0;
+
+	/*
+	 * Take a reference for this transaction on the buf item.
+	 */
+	atomic_inc(&bip->bli_refcount);
+
+	/*
+	 * Get a log_item_desc to point at the new item.
+	 */
+	(void) xfs_trans_add_item(tp, (xfs_log_item_t*)bip);
+
+	/*
+	 * Initialize b_fsprivate2 so we can find it with incore_match()
+	 * above.
+	 */
+	XFS_BUF_SET_FSPRIVATE2(bp, tp);
+
+	xfs_buftrace("TRANS GET", bp);
+	xfs_buf_item_trace("GET", bip);
+	return (bp);
+}
+
+/*
+ * Get and lock the superblock buffer of this file system for the
+ * given transaction.
+ *
+ * We don't need to use incore_match() here, because the superblock
+ * buffer is a private buffer which we keep a pointer to in the
+ * mount structure.
+ */
+xfs_buf_t *
+xfs_trans_getsb(xfs_trans_t	*tp,
+		struct xfs_mount *mp,
+		int		flags)
+{
+	xfs_buf_t		*bp;
+	xfs_buf_log_item_t	*bip;
+
+	/*
+	 * Default to just trying to lock the superblock buffer
+	 * if tp is NULL.
+	 */
+	if (tp == NULL) {
+		return (xfs_getsb(mp, flags));
+	}
+
+	/*
+	 * If the superblock buffer already has this transaction
+	 * pointer in its b_fsprivate2 field, then we know we already
+	 * have it locked.  In this case we just increment the lock
+	 * recursion count and return the buffer to the caller.
+	 */
+	bp = mp->m_sb_bp;
+	if (XFS_BUF_FSPRIVATE2(bp, xfs_trans_t *) == tp) {
+		bip = XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t*);
+		ASSERT(bip != NULL);
+		ASSERT(atomic_read(&bip->bli_refcount) > 0);
+		bip->bli_recur++;
+		xfs_buf_item_trace("GETSB RECUR", bip);
+		return (bp);
+	}
+
+	bp = xfs_getsb(mp, flags);
+	if (bp == NULL) {
+		return NULL;
+	}
+
+	/*
+	 * The xfs_buf_log_item pointer is stored in b_fsprivate.  If
+	 * it doesn't have one yet, then allocate one and initialize it.
+	 * The checks to see if one is there are in xfs_buf_item_init().
+	 */
+	xfs_buf_item_init(bp, mp);
+
+	/*
+	 * Set the recursion count for the buffer within this transaction
+	 * to 0.
+	 */
+	bip = XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t*);
+	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
+	ASSERT(!(bip->bli_format.blf_flags & XFS_BLI_CANCEL));
+	ASSERT(!(bip->bli_flags & XFS_BLI_LOGGED));
+	bip->bli_recur = 0;
+
+	/*
+	 * Take a reference for this transaction on the buf item.
+	 */
+	atomic_inc(&bip->bli_refcount);
+
+	/*
+	 * Get a log_item_desc to point at the new item.
+	 */
+	(void) xfs_trans_add_item(tp, (xfs_log_item_t*)bip);
+
+	/*
+	 * Initialize b_fsprivate2 so we can find it with incore_match()
+	 * above.
+	 */
+	XFS_BUF_SET_FSPRIVATE2(bp, tp);
+
+	xfs_buf_item_trace("GETSB", bip);
+	return (bp);
+}
+
+#ifdef DEBUG
+xfs_buftarg_t *xfs_error_target;
+int	xfs_do_error;
+int	xfs_req_num;
+int	xfs_error_mod = 33;
+#endif
+
+/*
+ * Get and lock the buffer for the caller if it is not already
+ * locked within the given transaction.  If it has not yet been
+ * read in, read it from disk. If it is already locked
+ * within the transaction and already read in, just increment its
+ * lock recursion count and return a pointer to it.
+ *
+ * Use the fast path function xfs_trans_buf_item_match() or the buffer
+ * cache routine incore_match() to find the buffer
+ * if it is already owned by this transaction.
+ *
+ * If we don't already own the buffer, use read_buf() to get it.
+ * If it doesn't yet have an associated xfs_buf_log_item structure,
+ * then allocate one and add the item to this transaction.
+ *
+ * If the transaction pointer is NULL, make this just a normal
+ * read_buf() call.
+ */
+int
+xfs_trans_read_buf(
+	xfs_mount_t	*mp,
+	xfs_trans_t	*tp,
+	xfs_buftarg_t	*target,
+	xfs_daddr_t	blkno,
+	int		len,
+	uint		flags,
+	xfs_buf_t	**bpp)
+{
+	xfs_buf_t		*bp;
+	xfs_buf_log_item_t	*bip;
+	int			error;
+
+	if (flags == 0)
+		flags = XFS_BUF_LOCK | XFS_BUF_MAPPED;
+
+	/*
+	 * Default to a normal get_buf() call if the tp is NULL.
+	 */
+	if (tp == NULL) {
+		bp = xfs_buf_read_flags(target, blkno, len, flags | BUF_BUSY);
+		if (!bp)
+			return XFS_ERROR(ENOMEM);
+
+		if ((bp != NULL) && (XFS_BUF_GETERROR(bp) != 0)) {
+			xfs_ioerror_alert("xfs_trans_read_buf", mp,
+					  bp, blkno);
+			error = XFS_BUF_GETERROR(bp);
+			xfs_buf_relse(bp);
+			return error;
+		}
+#ifdef DEBUG
+		if (xfs_do_error && (bp != NULL)) {
+			if (xfs_error_target == target) {
+				if (((xfs_req_num++) % xfs_error_mod) == 0) {
+					xfs_buf_relse(bp);
+					printk("Returning error!\n");
+					return XFS_ERROR(EIO);
+				}
+			}
+		}
+#endif
+		if (XFS_FORCED_SHUTDOWN(mp))
+			goto shutdown_abort;
+		*bpp = bp;
+		return 0;
+	}
+
+	/*
+	 * If we find the buffer in the cache with this transaction
+	 * pointer in its b_fsprivate2 field, then we know we already
+	 * have it locked.  If it is already read in we just increment
+	 * the lock recursion count and return the buffer to the caller.
+	 * If the buffer is not yet read in, then we read it in, increment
+	 * the lock recursion count, and return it to the caller.
+	 */
+	if (tp->t_items.lic_next == NULL) {
+		bp = xfs_trans_buf_item_match(tp, target, blkno, len);
+	} else {
+		bp = xfs_trans_buf_item_match_all(tp, target, blkno, len);
+	}
+	if (bp != NULL) {
+		ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
+		ASSERT(XFS_BUF_FSPRIVATE2(bp, xfs_trans_t *) == tp);
+		ASSERT(XFS_BUF_FSPRIVATE(bp, void *) != NULL);
+		ASSERT((XFS_BUF_ISERROR(bp)) == 0);
+		if (!(XFS_BUF_ISDONE(bp))) {
+			xfs_buftrace("READ_BUF_INCORE !DONE", bp);
+			ASSERT(!XFS_BUF_ISASYNC(bp));
+			XFS_BUF_READ(bp);
+			xfsbdstrat(tp->t_mountp, bp);
+			xfs_iowait(bp);
+			if (XFS_BUF_GETERROR(bp) != 0) {
+				xfs_ioerror_alert("xfs_trans_read_buf", mp,
+						  bp, blkno);
+				error = XFS_BUF_GETERROR(bp);
+				xfs_buf_relse(bp);
+				/*
+				 * We can gracefully recover from most
+				 * read errors. Ones we can't are those
+				 * that happen after the transaction's
+				 * already dirty.
+				 */
+				if (tp->t_flags & XFS_TRANS_DIRTY)
+					xfs_force_shutdown(tp->t_mountp,
+							   XFS_METADATA_IO_ERROR);
+				return error;
+			}
+		}
+		/*
+		 * We never locked this buf ourselves, so we shouldn't
+		 * brelse it either. Just get out.
+		 */
+		if (XFS_FORCED_SHUTDOWN(mp)) {
+			xfs_buftrace("READ_BUF_INCORE XFSSHUTDN", bp);
+			*bpp = NULL;
+			return XFS_ERROR(EIO);
+		}
+
+
+		bip = XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t*);
+		bip->bli_recur++;
+
+		ASSERT(atomic_read(&bip->bli_refcount) > 0);
+		xfs_buf_item_trace("READ RECUR", bip);
+		*bpp = bp;
+		return 0;
+	}
+
+	/*
+	 * We always specify the BUF_BUSY flag within a transaction so
+	 * that get_buf does not try to push out a delayed write buffer
+	 * which might cause another transaction to take place (if the
+	 * buffer was delayed alloc).  Such recursive transactions can
+	 * easily deadlock with our current transaction as well as cause
+	 * us to run out of stack space.
+	 */
+	bp = xfs_buf_read_flags(target, blkno, len, flags | BUF_BUSY);
+	if (bp == NULL) {
+		*bpp = NULL;
+		return 0;
+	}
+	if (XFS_BUF_GETERROR(bp) != 0) {
+	    XFS_BUF_SUPER_STALE(bp);
+		xfs_buftrace("READ ERROR", bp);
+		error = XFS_BUF_GETERROR(bp);
+
+		xfs_ioerror_alert("xfs_trans_read_buf", mp,
+				  bp, blkno);
+		if (tp->t_flags & XFS_TRANS_DIRTY)
+			xfs_force_shutdown(tp->t_mountp, XFS_METADATA_IO_ERROR);
+		xfs_buf_relse(bp);
+		return error;
+	}
+#ifdef DEBUG
+	if (xfs_do_error && !(tp->t_flags & XFS_TRANS_DIRTY)) {
+		if (xfs_error_target == target) {
+			if (((xfs_req_num++) % xfs_error_mod) == 0) {
+				xfs_force_shutdown(tp->t_mountp,
+						   XFS_METADATA_IO_ERROR);
+				xfs_buf_relse(bp);
+				printk("Returning error in trans!\n");
+				return XFS_ERROR(EIO);
+			}
+		}
+	}
+#endif
+	if (XFS_FORCED_SHUTDOWN(mp))
+		goto shutdown_abort;
+
+	/*
+	 * The xfs_buf_log_item pointer is stored in b_fsprivate.  If
+	 * it doesn't have one yet, then allocate one and initialize it.
+	 * The checks to see if one is there are in xfs_buf_item_init().
+	 */
+	xfs_buf_item_init(bp, tp->t_mountp);
+
+	/*
+	 * Set the recursion count for the buffer within this transaction
+	 * to 0.
+	 */
+	bip = XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t*);
+	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
+	ASSERT(!(bip->bli_format.blf_flags & XFS_BLI_CANCEL));
+	ASSERT(!(bip->bli_flags & XFS_BLI_LOGGED));
+	bip->bli_recur = 0;
+
+	/*
+	 * Take a reference for this transaction on the buf item.
+	 */
+	atomic_inc(&bip->bli_refcount);
+
+	/*
+	 * Get a log_item_desc to point at the new item.
+	 */
+	(void) xfs_trans_add_item(tp, (xfs_log_item_t*)bip);
+
+	/*
+	 * Initialize b_fsprivate2 so we can find it with incore_match()
+	 * above.
+	 */
+	XFS_BUF_SET_FSPRIVATE2(bp, tp);
+
+	xfs_buftrace("TRANS READ", bp);
+	xfs_buf_item_trace("READ", bip);
+	*bpp = bp;
+	return 0;
+
+shutdown_abort:
+	/*
+	 * the theory here is that buffer is good but we're
+	 * bailing out because the filesystem is being forcibly
+	 * shut down.  So we should leave the b_flags alone since
+	 * the buffer's not staled and just get out.
+	 */
+#if defined(DEBUG)
+	if (XFS_BUF_ISSTALE(bp) && XFS_BUF_ISDELAYWRITE(bp))
+		cmn_err(CE_NOTE, "about to pop assert, bp == 0x%p", bp);
+#endif
+	ASSERT((XFS_BUF_BFLAGS(bp) & (XFS_B_STALE|XFS_B_DELWRI)) !=
+						(XFS_B_STALE|XFS_B_DELWRI));
+
+	xfs_buftrace("READ_BUF XFSSHUTDN", bp);
+	xfs_buf_relse(bp);
+	*bpp = NULL;
+	return XFS_ERROR(EIO);
+}
+
+
+/*
+ * Release the buffer bp which was previously acquired with one of the
+ * xfs_trans_... buffer allocation routines if the buffer has not
+ * been modified within this transaction.  If the buffer is modified
+ * within this transaction, do decrement the recursion count but do
+ * not release the buffer even if the count goes to 0.  If the buffer is not
+ * modified within the transaction, decrement the recursion count and
+ * release the buffer if the recursion count goes to 0.
+ *
+ * If the buffer is to be released and it was not modified before
+ * this transaction began, then free the buf_log_item associated with it.
+ *
+ * If the transaction pointer is NULL, make this just a normal
+ * brelse() call.
+ */
+void
+xfs_trans_brelse(xfs_trans_t	*tp,
+		 xfs_buf_t	*bp)
+{
+	xfs_buf_log_item_t	*bip;
+	xfs_log_item_t		*lip;
+	xfs_log_item_desc_t	*lidp;
+
+	/*
+	 * Default to a normal brelse() call if the tp is NULL.
+	 */
+	if (tp == NULL) {
+		ASSERT(XFS_BUF_FSPRIVATE2(bp, void *) == NULL);
+		/*
+		 * If there's a buf log item attached to the buffer,
+		 * then let the AIL know that the buffer is being
+		 * unlocked.
+		 */
+		if (XFS_BUF_FSPRIVATE(bp, void *) != NULL) {
+			lip = XFS_BUF_FSPRIVATE(bp, xfs_log_item_t *);
+			if (lip->li_type == XFS_LI_BUF) {
+				bip = XFS_BUF_FSPRIVATE(bp,xfs_buf_log_item_t*);
+				xfs_trans_unlocked_item(
+						bip->bli_item.li_mountp,
+						lip);
+			}
+		}
+		xfs_buf_relse(bp);
+		return;
+	}
+
+	ASSERT(XFS_BUF_FSPRIVATE2(bp, xfs_trans_t *) == tp);
+	bip = XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t *);
+	ASSERT(bip->bli_item.li_type == XFS_LI_BUF);
+	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
+	ASSERT(!(bip->bli_format.blf_flags & XFS_BLI_CANCEL));
+	ASSERT(atomic_read(&bip->bli_refcount) > 0);
+
+	/*
+	 * Find the item descriptor pointing to this buffer's
+	 * log item.  It must be there.
+	 */
+	lidp = xfs_trans_find_item(tp, (xfs_log_item_t*)bip);
+	ASSERT(lidp != NULL);
+
+	/*
+	 * If the release is just for a recursive lock,
+	 * then decrement the count and return.
+	 */
+	if (bip->bli_recur > 0) {
+		bip->bli_recur--;
+		xfs_buf_item_trace("RELSE RECUR", bip);
+		return;
+	}
+
+	/*
+	 * If the buffer is dirty within this transaction, we can't
+	 * release it until we commit.
+	 */
+	if (lidp->lid_flags & XFS_LID_DIRTY) {
+		xfs_buf_item_trace("RELSE DIRTY", bip);
+		return;
+	}
+
+	/*
+	 * If the buffer has been invalidated, then we can't release
+	 * it until the transaction commits to disk unless it is re-dirtied
+	 * as part of this transaction.  This prevents us from pulling
+	 * the item from the AIL before we should.
+	 */
+	if (bip->bli_flags & XFS_BLI_STALE) {
+		xfs_buf_item_trace("RELSE STALE", bip);
+		return;
+	}
+
+	ASSERT(!(bip->bli_flags & XFS_BLI_LOGGED));
+	xfs_buf_item_trace("RELSE", bip);
+
+	/*
+	 * Free up the log item descriptor tracking the released item.
+	 */
+	xfs_trans_free_item(tp, lidp);
+
+	/*
+	 * Clear the hold flag in the buf log item if it is set.
+	 * We wouldn't want the next user of the buffer to
+	 * get confused.
+	 */
+	if (bip->bli_flags & XFS_BLI_HOLD) {
+		bip->bli_flags &= ~XFS_BLI_HOLD;
+	}
+
+	/*
+	 * Drop our reference to the buf log item.
+	 */
+	atomic_dec(&bip->bli_refcount);
+
+	/*
+	 * If the buf item is not tracking data in the log, then
+	 * we must free it before releasing the buffer back to the
+	 * free pool.  Before releasing the buffer to the free pool,
+	 * clear the transaction pointer in b_fsprivate2 to dissolve
+	 * its relation to this transaction.
+	 */
+	if (!xfs_buf_item_dirty(bip)) {
+/***
+		ASSERT(bp->b_pincount == 0);
+***/
+		ASSERT(atomic_read(&bip->bli_refcount) == 0);
+		ASSERT(!(bip->bli_item.li_flags & XFS_LI_IN_AIL));
+		ASSERT(!(bip->bli_flags & XFS_BLI_INODE_ALLOC_BUF));
+		xfs_buf_item_relse(bp);
+		bip = NULL;
+	}
+	XFS_BUF_SET_FSPRIVATE2(bp, NULL);
+
+	/*
+	 * If we've still got a buf log item on the buffer, then
+	 * tell the AIL that the buffer is being unlocked.
+	 */
+	if (bip != NULL) {
+		xfs_trans_unlocked_item(bip->bli_item.li_mountp,
+					(xfs_log_item_t*)bip);
+	}
+
+	xfs_buf_relse(bp);
+	return;
+}
+
+/*
+ * Add the locked buffer to the transaction.
+ * The buffer must be locked, and it cannot be associated with any
+ * transaction.
+ *
+ * If the buffer does not yet have a buf log item associated with it,
+ * then allocate one for it.  Then add the buf item to the transaction.
+ */
+void
+xfs_trans_bjoin(xfs_trans_t	*tp,
+		xfs_buf_t	*bp)
+{
+	xfs_buf_log_item_t	*bip;
+
+	ASSERT(XFS_BUF_ISBUSY(bp));
+	ASSERT(XFS_BUF_FSPRIVATE2(bp, void *) == NULL);
+
+	/*
+	 * The xfs_buf_log_item pointer is stored in b_fsprivate.  If
+	 * it doesn't have one yet, then allocate one and initialize it.
+	 * The checks to see if one is there are in xfs_buf_item_init().
+	 */
+	xfs_buf_item_init(bp, tp->t_mountp);
+	bip = XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t *);
+	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
+	ASSERT(!(bip->bli_format.blf_flags & XFS_BLI_CANCEL));
+	ASSERT(!(bip->bli_flags & XFS_BLI_LOGGED));
+
+	/*
+	 * Take a reference for this transaction on the buf item.
+	 */
+	atomic_inc(&bip->bli_refcount);
+
+	/*
+	 * Get a log_item_desc to point at the new item.
+	 */
+	(void) xfs_trans_add_item(tp, (xfs_log_item_t *)bip);
+
+	/*
+	 * Initialize b_fsprivate2 so we can find it with incore_match()
+	 * in xfs_trans_get_buf() and friends above.
+	 */
+	XFS_BUF_SET_FSPRIVATE2(bp, tp);
+
+	xfs_buf_item_trace("BJOIN", bip);
+}
+
+/*
+ * Mark the buffer as not needing to be unlocked when the buf item's
+ * IOP_UNLOCK() routine is called.  The buffer must already be locked
+ * and associated with the given transaction.
+ */
+/* ARGSUSED */
+void
+xfs_trans_bhold(xfs_trans_t	*tp,
+		xfs_buf_t	*bp)
+{
+	xfs_buf_log_item_t	*bip;
+
+	ASSERT(XFS_BUF_ISBUSY(bp));
+	ASSERT(XFS_BUF_FSPRIVATE2(bp, xfs_trans_t *) == tp);
+	ASSERT(XFS_BUF_FSPRIVATE(bp, void *) != NULL);
+
+	bip = XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t *);
+	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
+	ASSERT(!(bip->bli_format.blf_flags & XFS_BLI_CANCEL));
+	ASSERT(atomic_read(&bip->bli_refcount) > 0);
+	bip->bli_flags |= XFS_BLI_HOLD;
+	xfs_buf_item_trace("BHOLD", bip);
+}
+
+/*
+ * This function is used to indicate that the buffer should not be
+ * unlocked until the transaction is committed to disk.  Since we
+ * are going to keep the lock held, make the transaction synchronous
+ * so that the lock is not held too long.
+ *
+ * It uses the log item descriptor flag XFS_LID_SYNC_UNLOCK to
+ * delay the buf items's unlock call until the transaction is
+ * committed to disk or aborted.
+ */
+void
+xfs_trans_bhold_until_committed(xfs_trans_t	*tp,
+				xfs_buf_t	*bp)
+{
+	xfs_log_item_desc_t	*lidp;
+	xfs_buf_log_item_t	*bip;
+
+	ASSERT(XFS_BUF_ISBUSY(bp));
+	ASSERT(XFS_BUF_FSPRIVATE2(bp, xfs_trans_t *) == tp);
+	ASSERT(XFS_BUF_FSPRIVATE(bp, void *) != NULL);
+
+	bip = XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t *);
+	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
+	ASSERT(!(bip->bli_format.blf_flags & XFS_BLI_CANCEL));
+	ASSERT(atomic_read(&bip->bli_refcount) > 0);
+	lidp = xfs_trans_find_item(tp, (xfs_log_item_t*)bip);
+	ASSERT(lidp != NULL);
+
+	lidp->lid_flags |= XFS_LID_SYNC_UNLOCK;
+	xfs_buf_item_trace("BHOLD UNTIL COMMIT", bip);
+
+	xfs_trans_set_sync(tp);
+}
+
+/*
+ * This is called to mark bytes first through last inclusive of the given
+ * buffer as needing to be logged when the transaction is committed.
+ * The buffer must already be associated with the given transaction.
+ *
+ * First and last are numbers relative to the beginning of this buffer,
+ * so the first byte in the buffer is numbered 0 regardless of the
+ * value of b_blkno.
+ */
+void
+xfs_trans_log_buf(xfs_trans_t	*tp,
+		  xfs_buf_t	*bp,
+		  uint		first,
+		  uint		last)
+{
+	xfs_buf_log_item_t	*bip;
+	xfs_log_item_desc_t	*lidp;
+
+	ASSERT(XFS_BUF_ISBUSY(bp));
+	ASSERT(XFS_BUF_FSPRIVATE2(bp, xfs_trans_t *) == tp);
+	ASSERT(XFS_BUF_FSPRIVATE(bp, void *) != NULL);
+	ASSERT((first <= last) && (last < XFS_BUF_COUNT(bp)));
+	ASSERT((XFS_BUF_IODONE_FUNC(bp) == NULL) ||
+	       (XFS_BUF_IODONE_FUNC(bp) == xfs_buf_iodone_callbacks));
+
+	/*
+	 * Mark the buffer as needing to be written out eventually,
+	 * and set its iodone function to remove the buffer's buf log
+	 * item from the AIL and free it when the buffer is flushed
+	 * to disk.  See xfs_buf_attach_iodone() for more details
+	 * on li_cb and xfs_buf_iodone_callbacks().
+	 * If we end up aborting this transaction, we trap this buffer
+	 * inside the b_bdstrat callback so that this won't get written to
+	 * disk.
+	 */
+	XFS_BUF_DELAYWRITE(bp);
+	XFS_BUF_DONE(bp);
+
+	bip = XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t *);
+	ASSERT(atomic_read(&bip->bli_refcount) > 0);
+	XFS_BUF_SET_IODONE_FUNC(bp, xfs_buf_iodone_callbacks);
+	bip->bli_item.li_cb = (void(*)(xfs_buf_t*,xfs_log_item_t*))xfs_buf_iodone;
+
+	/*
+	 * If we invalidated the buffer within this transaction, then
+	 * cancel the invalidation now that we're dirtying the buffer
+	 * again.  There are no races with the code in xfs_buf_item_unpin(),
+	 * because we have a reference to the buffer this entire time.
+	 */
+	if (bip->bli_flags & XFS_BLI_STALE) {
+		xfs_buf_item_trace("BLOG UNSTALE", bip);
+		bip->bli_flags &= ~XFS_BLI_STALE;
+		/* note this will have to change for page_buf interface... unstale isn't really an option RMC */
+		ASSERT(XFS_BUF_ISSTALE(bp));
+		XFS_BUF_UNSTALE(bp);
+		bip->bli_format.blf_flags &= ~XFS_BLI_CANCEL;
+	}
+
+	lidp = xfs_trans_find_item(tp, (xfs_log_item_t*)bip);
+	ASSERT(lidp != NULL);
+
+	tp->t_flags |= XFS_TRANS_DIRTY;
+	lidp->lid_flags |= XFS_LID_DIRTY;
+	lidp->lid_flags &= ~XFS_LID_BUF_STALE;
+	bip->bli_flags |= XFS_BLI_LOGGED;
+	xfs_buf_item_log(bip, first, last);
+	xfs_buf_item_trace("BLOG", bip);
+}
+
+
+/*
+ * This called to invalidate a buffer that is being used within
+ * a transaction.  Typically this is because the blocks in the
+ * buffer are being freed, so we need to prevent it from being
+ * written out when we're done.  Allowing it to be written again
+ * might overwrite data in the free blocks if they are reallocated
+ * to a file.
+ *
+ * We prevent the buffer from being written out by clearing the
+ * B_DELWRI flag.  We can't always
+ * get rid of the buf log item at this point, though, because
+ * the buffer may still be pinned by another transaction.  If that
+ * is the case, then we'll wait until the buffer is committed to
+ * disk for the last time (we can tell by the ref count) and
+ * free it in xfs_buf_item_unpin().  Until it is cleaned up we
+ * will keep the buffer locked so that the buffer and buf log item
+ * are not reused.
+ */
+void
+xfs_trans_binval(
+	xfs_trans_t	*tp,
+	xfs_buf_t	*bp)
+{
+	xfs_log_item_desc_t	*lidp;
+	xfs_buf_log_item_t	*bip;
+
+	ASSERT(XFS_BUF_ISBUSY(bp));
+	ASSERT(XFS_BUF_FSPRIVATE2(bp, xfs_trans_t *) == tp);
+	ASSERT(XFS_BUF_FSPRIVATE(bp, void *) != NULL);
+
+	bip = XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t *);
+	lidp = xfs_trans_find_item(tp, (xfs_log_item_t*)bip);
+	ASSERT(lidp != NULL);
+	ASSERT(atomic_read(&bip->bli_refcount) > 0);
+
+	if (bip->bli_flags & XFS_BLI_STALE) {
+		/*
+		 * If the buffer is already invalidated, then
+		 * just return.
+		 */
+		ASSERT(!(XFS_BUF_ISDELAYWRITE(bp)));
+		ASSERT(XFS_BUF_ISSTALE(bp));
+		ASSERT(!(bip->bli_flags & (XFS_BLI_LOGGED | XFS_BLI_DIRTY)));
+		ASSERT(!(bip->bli_format.blf_flags & XFS_BLI_INODE_BUF));
+		ASSERT(bip->bli_format.blf_flags & XFS_BLI_CANCEL);
+		ASSERT(lidp->lid_flags & XFS_LID_DIRTY);
+		ASSERT(tp->t_flags & XFS_TRANS_DIRTY);
+		xfs_buftrace("XFS_BINVAL RECUR", bp);
+		xfs_buf_item_trace("BINVAL RECUR", bip);
+		return;
+	}
+
+	/*
+	 * Clear the dirty bit in the buffer and set the STALE flag
+	 * in the buf log item.  The STALE flag will be used in
+	 * xfs_buf_item_unpin() to determine if it should clean up
+	 * when the last reference to the buf item is given up.
+	 * We set the XFS_BLI_CANCEL flag in the buf log format structure
+	 * and log the buf item.  This will be used at recovery time
+	 * to determine that copies of the buffer in the log before
+	 * this should not be replayed.
+	 * We mark the item descriptor and the transaction dirty so
+	 * that we'll hold the buffer until after the commit.
+	 *
+	 * Since we're invalidating the buffer, we also clear the state
+	 * about which parts of the buffer have been logged.  We also
+	 * clear the flag indicating that this is an inode buffer since
+	 * the data in the buffer will no longer be valid.
+	 *
+	 * We set the stale bit in the buffer as well since we're getting
+	 * rid of it.
+	 */
+	XFS_BUF_UNDELAYWRITE(bp);
+	XFS_BUF_STALE(bp);
+	bip->bli_flags |= XFS_BLI_STALE;
+	bip->bli_flags &= ~(XFS_BLI_LOGGED | XFS_BLI_DIRTY);
+	bip->bli_format.blf_flags &= ~XFS_BLI_INODE_BUF;
+	bip->bli_format.blf_flags |= XFS_BLI_CANCEL;
+	memset((char *)(bip->bli_format.blf_data_map), 0,
+	      (bip->bli_format.blf_map_size * sizeof(uint)));
+	lidp->lid_flags |= XFS_LID_DIRTY|XFS_LID_BUF_STALE;
+	tp->t_flags |= XFS_TRANS_DIRTY;
+	xfs_buftrace("XFS_BINVAL", bp);
+	xfs_buf_item_trace("BINVAL", bip);
+}
+
+/*
+ * This call is used to indicate that the buffer contains on-disk
+ * inodes which must be handled specially during recovery.  They
+ * require special handling because only the di_next_unlinked from
+ * the inodes in the buffer should be recovered.  The rest of the
+ * data in the buffer is logged via the inodes themselves.
+ *
+ * All we do is set the XFS_BLI_INODE_BUF flag in the buffer's log
+ * format structure so that we'll know what to do at recovery time.
+ */
+/* ARGSUSED */
+void
+xfs_trans_inode_buf(
+	xfs_trans_t	*tp,
+	xfs_buf_t	*bp)
+{
+	xfs_buf_log_item_t	*bip;
+
+	ASSERT(XFS_BUF_ISBUSY(bp));
+	ASSERT(XFS_BUF_FSPRIVATE2(bp, xfs_trans_t *) == tp);
+	ASSERT(XFS_BUF_FSPRIVATE(bp, void *) != NULL);
+
+	bip = XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t *);
+	ASSERT(atomic_read(&bip->bli_refcount) > 0);
+
+	bip->bli_format.blf_flags |= XFS_BLI_INODE_BUF;
+}
+
+/*
+ * This call is used to indicate that the buffer is going to
+ * be staled and was an inode buffer. This means it gets
+ * special processing during unpin - where any inodes 
+ * associated with the buffer should be removed from ail.
+ * There is also special processing during recovery,
+ * any replay of the inodes in the buffer needs to be
+ * prevented as the buffer may have been reused.
+ */
+void
+xfs_trans_stale_inode_buf(
+	xfs_trans_t	*tp,
+	xfs_buf_t	*bp)
+{
+	xfs_buf_log_item_t	*bip;
+
+	ASSERT(XFS_BUF_ISBUSY(bp));
+	ASSERT(XFS_BUF_FSPRIVATE2(bp, xfs_trans_t *) == tp);
+	ASSERT(XFS_BUF_FSPRIVATE(bp, void *) != NULL);
+
+	bip = XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t *);
+	ASSERT(atomic_read(&bip->bli_refcount) > 0);
+
+	bip->bli_flags |= XFS_BLI_STALE_INODE;
+	bip->bli_item.li_cb = (void(*)(xfs_buf_t*,xfs_log_item_t*))
+		xfs_buf_iodone;
+}
+
+
+
+/*
+ * Mark the buffer as being one which contains newly allocated
+ * inodes.  We need to make sure that even if this buffer is
+ * relogged as an 'inode buf' we still recover all of the inode
+ * images in the face of a crash.  This works in coordination with
+ * xfs_buf_item_committed() to ensure that the buffer remains in the
+ * AIL at its original location even after it has been relogged.
+ */
+/* ARGSUSED */
+void
+xfs_trans_inode_alloc_buf(
+	xfs_trans_t	*tp,
+	xfs_buf_t	*bp)
+{
+	xfs_buf_log_item_t	*bip;
+
+	ASSERT(XFS_BUF_ISBUSY(bp));
+	ASSERT(XFS_BUF_FSPRIVATE2(bp, xfs_trans_t *) == tp);
+	ASSERT(XFS_BUF_FSPRIVATE(bp, void *) != NULL);
+
+	bip = XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t *);
+	ASSERT(atomic_read(&bip->bli_refcount) > 0);
+
+	bip->bli_flags |= XFS_BLI_INODE_ALLOC_BUF;
+}
+
+
+/*
+ * Similar to xfs_trans_inode_buf(), this marks the buffer as a cluster of
+ * dquots. However, unlike in inode buffer recovery, dquot buffers get
+ * recovered in their entirety. (Hence, no XFS_BLI_DQUOT_ALLOC_BUF flag).
+ * The only thing that makes dquot buffers different from regular
+ * buffers is that we must not replay dquot bufs when recovering
+ * if a _corresponding_ quotaoff has happened. We also have to distinguish
+ * between usr dquot bufs and grp dquot bufs, because usr and grp quotas
+ * can be turned off independently.
+ */
+/* ARGSUSED */
+void
+xfs_trans_dquot_buf(
+	xfs_trans_t	*tp,
+	xfs_buf_t	*bp,
+	uint		type)
+{
+	xfs_buf_log_item_t	*bip;
+
+	ASSERT(XFS_BUF_ISBUSY(bp));
+	ASSERT(XFS_BUF_FSPRIVATE2(bp, xfs_trans_t *) == tp);
+	ASSERT(XFS_BUF_FSPRIVATE(bp, void *) != NULL);
+	ASSERT(type == XFS_BLI_UDQUOT_BUF ||
+	       type == XFS_BLI_GDQUOT_BUF);
+
+	bip = XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t *);
+	ASSERT(atomic_read(&bip->bli_refcount) > 0);
+
+	bip->bli_format.blf_flags |= type;
+}
+
+/*
+ * Check to see if a buffer matching the given parameters is already
+ * a part of the given transaction.  Only check the first, embedded
+ * chunk, since we don't want to spend all day scanning large transactions.
+ */
+STATIC xfs_buf_t *
+xfs_trans_buf_item_match(
+	xfs_trans_t	*tp,
+	xfs_buftarg_t	*target,
+	xfs_daddr_t	blkno,
+	int		len)
+{
+	xfs_log_item_chunk_t	*licp;
+	xfs_log_item_desc_t	*lidp;
+	xfs_buf_log_item_t	*blip;
+	xfs_buf_t		*bp;
+	int			i;
+
+	bp = NULL;
+	len = BBTOB(len);
+	licp = &tp->t_items;
+	if (!XFS_LIC_ARE_ALL_FREE(licp)) {
+		for (i = 0; i < licp->lic_unused; i++) {
+			/*
+			 * Skip unoccupied slots.
+			 */
+			if (XFS_LIC_ISFREE(licp, i)) {
+				continue;
+			}
+
+			lidp = XFS_LIC_SLOT(licp, i);
+			blip = (xfs_buf_log_item_t *)lidp->lid_item;
+			if (blip->bli_item.li_type != XFS_LI_BUF) {
+				continue;
+			}
+
+			bp = blip->bli_buf;
+			if ((XFS_BUF_TARGET(bp) == target) &&
+			    (XFS_BUF_ADDR(bp) == blkno) &&
+			    (XFS_BUF_COUNT(bp) == len)) {
+				/*
+				 * We found it.  Break out and
+				 * return the pointer to the buffer.
+				 */
+				break;
+			} else {
+				bp = NULL;
+			}
+		}
+	}
+	return bp;
+}
+
+/*
+ * Check to see if a buffer matching the given parameters is already
+ * a part of the given transaction.  Check all the chunks, we
+ * want to be thorough.
+ */
+STATIC xfs_buf_t *
+xfs_trans_buf_item_match_all(
+	xfs_trans_t	*tp,
+	xfs_buftarg_t	*target,
+	xfs_daddr_t	blkno,
+	int		len)
+{
+	xfs_log_item_chunk_t	*licp;
+	xfs_log_item_desc_t	*lidp;
+	xfs_buf_log_item_t	*blip;
+	xfs_buf_t		*bp;
+	int			i;
+
+	bp = NULL;
+	len = BBTOB(len);
+	for (licp = &tp->t_items; licp != NULL; licp = licp->lic_next) {
+		if (XFS_LIC_ARE_ALL_FREE(licp)) {
+			ASSERT(licp == &tp->t_items);
+			ASSERT(licp->lic_next == NULL);
+			return NULL;
+		}
+		for (i = 0; i < licp->lic_unused; i++) {
+			/*
+			 * Skip unoccupied slots.
+			 */
+			if (XFS_LIC_ISFREE(licp, i)) {
+				continue;
+			}
+
+			lidp = XFS_LIC_SLOT(licp, i);
+			blip = (xfs_buf_log_item_t *)lidp->lid_item;
+			if (blip->bli_item.li_type != XFS_LI_BUF) {
+				continue;
+			}
+
+			bp = blip->bli_buf;
+			if ((XFS_BUF_TARGET(bp) == target) &&
+			    (XFS_BUF_ADDR(bp) == blkno) &&
+			    (XFS_BUF_COUNT(bp) == len)) {
+				/*
+				 * We found it.  Break out and
+				 * return the pointer to the buffer.
+				 */
+				return bp;
+			}
+		}
+	}
+	return NULL;
+}
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)