fs/xfs/xfs_rw.c - kernel/msm-4.19 - Gitiles

 /*
  * Copyright (c) 2000-2006 Silicon Graphics, Inc.
  * All Rights Reserved.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
  * published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it would be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write the Free Software Foundation,
  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 #include "xfs.h"
 #include "xfs_fs.h"
 #include "xfs_types.h"
 #include "xfs_bit.h"
 #include "xfs_log.h"
 #include "xfs_inum.h"
 #include "xfs_trans.h"
 #include "xfs_sb.h"
 #include "xfs_ag.h"
 #include "xfs_dir.h"
 #include "xfs_dir2.h"
 #include "xfs_dmapi.h"
 #include "xfs_mount.h"
 #include "xfs_bmap_btree.h"
 #include "xfs_alloc_btree.h"
 #include "xfs_ialloc_btree.h"
 #include "xfs_dir_sf.h"
 #include "xfs_dir2_sf.h"
 #include "xfs_attr_sf.h"
 #include "xfs_dinode.h"
 #include "xfs_inode.h"
 #include "xfs_inode_item.h"
 #include "xfs_itable.h"
 #include "xfs_btree.h"
 #include "xfs_alloc.h"
 #include "xfs_ialloc.h"
 #include "xfs_attr.h"
 #include "xfs_bmap.h"
 #include "xfs_acl.h"
 #include "xfs_mac.h"
 #include "xfs_error.h"
 #include "xfs_buf_item.h"
 #include "xfs_rw.h"

 /*
  * This is a subroutine for xfs_write() and other writers (xfs_ioctl)
  * which clears the setuid and setgid bits when a file is written.
  */
 int
 xfs_write_clear_setuid(
 	xfs_inode_t	*ip)
 {
 	xfs_mount_t	*mp;
 	xfs_trans_t	*tp;
 	int		error;

 	mp = ip->i_mount;
 	tp = xfs_trans_alloc(mp, XFS_TRANS_WRITEID);
 	if ((error = xfs_trans_reserve(tp, 0,
 				      XFS_WRITEID_LOG_RES(mp),
 				      0, 0, 0))) {
 		xfs_trans_cancel(tp, 0);
 		return error;
 	}
 	xfs_ilock(ip, XFS_ILOCK_EXCL);
 	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 	xfs_trans_ihold(tp, ip);
 	ip->i_d.di_mode &= ~S_ISUID;

 	/*
 	 * Note that we don't have to worry about mandatory
 	 * file locking being disabled here because we only
 	 * clear the S_ISGID bit if the Group execute bit is
 	 * on, but if it was on then mandatory locking wouldn't
 	 * have been enabled.
 	 */
 	if (ip->i_d.di_mode & S_IXGRP) {
 		ip->i_d.di_mode &= ~S_ISGID;
 	}
 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 	xfs_trans_set_sync(tp);
 	error = xfs_trans_commit(tp, 0, NULL);
 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 	return 0;
 }

 /*
  * Handle logging requirements of various synchronous types of write.
  */
 int
 xfs_write_sync_logforce(
 	xfs_mount_t	*mp,
 	xfs_inode_t	*ip)
 {
 	int		error = 0;

 	/*
 	 * If we're treating this as O_DSYNC and we have not updated the
 	 * size, force the log.
 	 */
 	if (!(mp->m_flags & XFS_MOUNT_OSYNCISOSYNC) &&
 	    !(ip->i_update_size)) {
 		xfs_inode_log_item_t	*iip = ip->i_itemp;

 		/*
 		 * If an allocation transaction occurred
 		 * without extending the size, then we have to force
 		 * the log up the proper point to ensure that the
 		 * allocation is permanent.  We can't count on
 		 * the fact that buffered writes lock out direct I/O
 		 * writes - the direct I/O write could have extended
 		 * the size nontransactionally, then finished before
 		 * we started.  xfs_write_file will think that the file
 		 * didn't grow but the update isn't safe unless the
 		 * size change is logged.
 		 *
 		 * Force the log if we've committed a transaction
 		 * against the inode or if someone else has and
 		 * the commit record hasn't gone to disk (e.g.
 		 * the inode is pinned).  This guarantees that
 		 * all changes affecting the inode are permanent
 		 * when we return.
 		 */
 		if (iip && iip->ili_last_lsn) {
 			xfs_log_force(mp, iip->ili_last_lsn,
 					XFS_LOG_FORCE | XFS_LOG_SYNC);
 		} else if (xfs_ipincount(ip) > 0) {
 			xfs_log_force(mp, (xfs_lsn_t)0,
 					XFS_LOG_FORCE | XFS_LOG_SYNC);
 		}

 	} else {
 		xfs_trans_t	*tp;

 		/*
 		 * O_SYNC or O_DSYNC _with_ a size update are handled
 		 * the same way.
 		 *
 		 * If the write was synchronous then we need to make
 		 * sure that the inode modification time is permanent.
 		 * We'll have updated the timestamp above, so here
 		 * we use a synchronous transaction to log the inode.
 		 * It's not fast, but it's necessary.
 		 *
 		 * If this a dsync write and the size got changed
 		 * non-transactionally, then we need to ensure that
 		 * the size change gets logged in a synchronous
 		 * transaction.
 		 */
 		tp = xfs_trans_alloc(mp, XFS_TRANS_WRITE_SYNC);
 		if ((error = xfs_trans_reserve(tp, 0,
 						XFS_SWRITE_LOG_RES(mp),
 						0, 0, 0))) {
 			/* Transaction reserve failed */
 			xfs_trans_cancel(tp, 0);
 		} else {
 			/* Transaction reserve successful */
 			xfs_ilock(ip, XFS_ILOCK_EXCL);
 			xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 			xfs_trans_ihold(tp, ip);
 			xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 			xfs_trans_set_sync(tp);
 			error = xfs_trans_commit(tp, 0, NULL);
 			xfs_iunlock(ip, XFS_ILOCK_EXCL);
 		}
 	}

 	return error;
 }

 /*
  * Force a shutdown of the filesystem instantly while keeping
  * the filesystem consistent. We don't do an unmount here; just shutdown
  * the shop, make sure that absolutely nothing persistent happens to
  * this filesystem after this point.
  */

 void
 xfs_do_force_shutdown(
 	bhv_desc_t	*bdp,
 	int		flags,
 	char		*fname,
 	int		lnnum)
 {
 	int		logerror;
 	xfs_mount_t	*mp;

 	mp = XFS_BHVTOM(bdp);
 	logerror = flags & SHUTDOWN_LOG_IO_ERROR;

 	if (!(flags & SHUTDOWN_FORCE_UMOUNT)) {
 		cmn_err(CE_NOTE, "xfs_force_shutdown(%s,0x%x) called from "
 				 "line %d of file %s.  Return address = 0x%p",
 			mp->m_fsname, flags, lnnum, fname, __return_address);
 	}
 	/*
 	 * No need to duplicate efforts.
 	 */
 	if (XFS_FORCED_SHUTDOWN(mp) && !logerror)
 		return;

 	/*
 	 * This flags XFS_MOUNT_FS_SHUTDOWN, makes sure that we don't
 	 * queue up anybody new on the log reservations, and wakes up
 	 * everybody who's sleeping on log reservations to tell them
 	 * the bad news.
 	 */
 	if (xfs_log_force_umount(mp, logerror))
 		return;

 	if (flags & SHUTDOWN_CORRUPT_INCORE) {
 		xfs_cmn_err(XFS_PTAG_SHUTDOWN_CORRUPT, CE_ALERT, mp,
     "Corruption of in-memory data detected.  Shutting down filesystem: %s",
 			mp->m_fsname);
 		if (XFS_ERRLEVEL_HIGH <= xfs_error_level) {
 			xfs_stack_trace();
 		}
 	} else if (!(flags & SHUTDOWN_FORCE_UMOUNT)) {
 		if (logerror) {
 			xfs_cmn_err(XFS_PTAG_SHUTDOWN_LOGERROR, CE_ALERT, mp,
 		"Log I/O Error Detected.  Shutting down filesystem: %s",
 				mp->m_fsname);
 		} else if (flags & SHUTDOWN_DEVICE_REQ) {
 			xfs_cmn_err(XFS_PTAG_SHUTDOWN_IOERROR, CE_ALERT, mp,
 		"All device paths lost.  Shutting down filesystem: %s",
 				mp->m_fsname);
 		} else if (!(flags & SHUTDOWN_REMOTE_REQ)) {
 			xfs_cmn_err(XFS_PTAG_SHUTDOWN_IOERROR, CE_ALERT, mp,
 		"I/O Error Detected.  Shutting down filesystem: %s",
 				mp->m_fsname);
 		}
 	}
 	if (!(flags & SHUTDOWN_FORCE_UMOUNT)) {
 		cmn_err(CE_ALERT, "Please umount the filesystem, "
 				  "and rectify the problem(s)");
 	}
 }


 /*
  * Called when we want to stop a buffer from getting written or read.
  * We attach the EIO error, muck with its flags, and call biodone
  * so that the proper iodone callbacks get called.
  */
 int
 xfs_bioerror(
 	xfs_buf_t *bp)
 {

 #ifdef XFSERRORDEBUG
 	ASSERT(XFS_BUF_ISREAD(bp) || bp->b_iodone);
 #endif

 	/*
 	 * No need to wait until the buffer is unpinned.
 	 * We aren't flushing it.
 	 */
 	xfs_buftrace("XFS IOERROR", bp);
 	XFS_BUF_ERROR(bp, EIO);
 	/*
 	 * We're calling biodone, so delete B_DONE flag. Either way
 	 * we have to call the iodone callback, and calling biodone
 	 * probably is the best way since it takes care of
 	 * GRIO as well.
 	 */
 	XFS_BUF_UNREAD(bp);
 	XFS_BUF_UNDELAYWRITE(bp);
 	XFS_BUF_UNDONE(bp);
 	XFS_BUF_STALE(bp);

 	XFS_BUF_CLR_BDSTRAT_FUNC(bp);
 	xfs_biodone(bp);

 	return (EIO);
 }

 /*
  * Same as xfs_bioerror, except that we are releasing the buffer
  * here ourselves, and avoiding the biodone call.
  * This is meant for userdata errors; metadata bufs come with
  * iodone functions attached, so that we can track down errors.
  */
 int
 xfs_bioerror_relse(
 	xfs_buf_t *bp)
 {
 	int64_t fl;

 	ASSERT(XFS_BUF_IODONE_FUNC(bp) != xfs_buf_iodone_callbacks);
 	ASSERT(XFS_BUF_IODONE_FUNC(bp) != xlog_iodone);

 	xfs_buftrace("XFS IOERRELSE", bp);
 	fl = XFS_BUF_BFLAGS(bp);
 	/*
 	 * No need to wait until the buffer is unpinned.
 	 * We aren't flushing it.
 	 *
 	 * chunkhold expects B_DONE to be set, whether
 	 * we actually finish the I/O or not. We don't want to
 	 * change that interface.
 	 */
 	XFS_BUF_UNREAD(bp);
 	XFS_BUF_UNDELAYWRITE(bp);
 	XFS_BUF_DONE(bp);
 	XFS_BUF_STALE(bp);
 	XFS_BUF_CLR_IODONE_FUNC(bp);
 	XFS_BUF_CLR_BDSTRAT_FUNC(bp);
 	if (!(fl & XFS_B_ASYNC)) {
 		/*
 		 * Mark b_error and B_ERROR _both_.
 		 * Lot's of chunkcache code assumes that.
 		 * There's no reason to mark error for
 		 * ASYNC buffers.
 		 */
 		XFS_BUF_ERROR(bp, EIO);
 		XFS_BUF_V_IODONESEMA(bp);
 	} else {
 		xfs_buf_relse(bp);
 	}
 	return (EIO);
 }

 /*
  * Prints out an ALERT message about I/O error.
  */
 void
 xfs_ioerror_alert(
 	char			*func,
 	struct xfs_mount	*mp,
 	xfs_buf_t		*bp,
 	xfs_daddr_t		blkno)
 {
 	cmn_err(CE_ALERT,
  "I/O error in filesystem (\"%s\") meta-data dev %s block 0x%llx"
  "       (\"%s\") error %d buf count %zd",
 		(!mp || !mp->m_fsname) ? "(fs name not set)" : mp->m_fsname,
 		XFS_BUFTARG_NAME(XFS_BUF_TARGET(bp)),
 		(__uint64_t)blkno, func,
 		XFS_BUF_GETERROR(bp), XFS_BUF_COUNT(bp));
 }

 /*
  * This isn't an absolute requirement, but it is
  * just a good idea to call xfs_read_buf instead of
  * directly doing a read_buf call. For one, we shouldn't
  * be doing this disk read if we are in SHUTDOWN state anyway,
  * so this stops that from happening. Secondly, this does all
  * the error checking stuff and the brelse if appropriate for
  * the caller, so the code can be a little leaner.
  */

 int
 xfs_read_buf(
 	struct xfs_mount *mp,
 	xfs_buftarg_t	 *target,
 	xfs_daddr_t	 blkno,
 	int              len,
 	uint             flags,
 	xfs_buf_t	 **bpp)
 {
 	xfs_buf_t	 *bp;
 	int		 error;

 	if (flags)
 		bp = xfs_buf_read_flags(target, blkno, len, flags);
 	else
 		bp = xfs_buf_read(target, blkno, len, flags);
 	if (!bp)
 		return XFS_ERROR(EIO);
 	error = XFS_BUF_GETERROR(bp);
 	if (bp && !error && !XFS_FORCED_SHUTDOWN(mp)) {
 		*bpp = bp;
 	} else {
 		*bpp = NULL;
 		if (error) {
 			xfs_ioerror_alert("xfs_read_buf", mp, bp, XFS_BUF_ADDR(bp));
 		} else {
 			error = XFS_ERROR(EIO);
 		}
 		if (bp) {
 			XFS_BUF_UNDONE(bp);
 			XFS_BUF_UNDELAYWRITE(bp);
 			XFS_BUF_STALE(bp);
 			/*
 			 * brelse clears B_ERROR and b_error
 			 */
 			xfs_buf_relse(bp);
 		}
 	}
 	return (error);
 }

 /*
  * Wrapper around bwrite() so that we can trap
  * write errors, and act accordingly.
  */
 int
 xfs_bwrite(
 	struct xfs_mount *mp,
 	struct xfs_buf	 *bp)
 {
 	int	error;

 	/*
 	 * XXXsup how does this work for quotas.
 	 */
 	XFS_BUF_SET_BDSTRAT_FUNC(bp, xfs_bdstrat_cb);
 	XFS_BUF_SET_FSPRIVATE3(bp, mp);
 	XFS_BUF_WRITE(bp);

 	if ((error = XFS_bwrite(bp))) {
 		ASSERT(mp);
 		/*
 		 * Cannot put a buftrace here since if the buffer is not
 		 * B_HOLD then we will brelse() the buffer before returning
 		 * from bwrite and we could be tracing a buffer that has
 		 * been reused.
 		 */
 		xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR);
 	}
 	return (error);
 }
	/*
	* Copyright (c) 2000-2006 Silicon Graphics, Inc.
	* All Rights Reserved.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License as
	* published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it would be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	*/
	#include "xfs.h"
	#include "xfs_fs.h"
	#include "xfs_types.h"
	#include "xfs_bit.h"
	#include "xfs_log.h"
	#include "xfs_inum.h"
	#include "xfs_trans.h"
	#include "xfs_sb.h"
	#include "xfs_ag.h"
	#include "xfs_dir.h"
	#include "xfs_dir2.h"
	#include "xfs_dmapi.h"
	#include "xfs_mount.h"
	#include "xfs_bmap_btree.h"
	#include "xfs_alloc_btree.h"
	#include "xfs_ialloc_btree.h"
	#include "xfs_dir_sf.h"
	#include "xfs_dir2_sf.h"
	#include "xfs_attr_sf.h"
	#include "xfs_dinode.h"
	#include "xfs_inode.h"
	#include "xfs_inode_item.h"
	#include "xfs_itable.h"
	#include "xfs_btree.h"
	#include "xfs_alloc.h"
	#include "xfs_ialloc.h"
	#include "xfs_attr.h"
	#include "xfs_bmap.h"
	#include "xfs_acl.h"
	#include "xfs_mac.h"
	#include "xfs_error.h"
	#include "xfs_buf_item.h"
	#include "xfs_rw.h"

	/*
	* This is a subroutine for xfs_write() and other writers (xfs_ioctl)
	* which clears the setuid and setgid bits when a file is written.
	*/
	int
	xfs_write_clear_setuid(
	xfs_inode_t *ip)
	{
	xfs_mount_t *mp;
	xfs_trans_t *tp;
	int error;

	mp = ip->i_mount;
	tp = xfs_trans_alloc(mp, XFS_TRANS_WRITEID);
	if ((error = xfs_trans_reserve(tp, 0,
	XFS_WRITEID_LOG_RES(mp),
	0, 0, 0))) {
	xfs_trans_cancel(tp, 0);
	return error;
	}
	xfs_ilock(ip, XFS_ILOCK_EXCL);
	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
	xfs_trans_ihold(tp, ip);
	ip->i_d.di_mode &= ~S_ISUID;

	/*
	* Note that we don't have to worry about mandatory
	* file locking being disabled here because we only
	* clear the S_ISGID bit if the Group execute bit is
	* on, but if it was on then mandatory locking wouldn't
	* have been enabled.
	*/
	if (ip->i_d.di_mode & S_IXGRP) {
	ip->i_d.di_mode &= ~S_ISGID;
	}
	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
	xfs_trans_set_sync(tp);
	error = xfs_trans_commit(tp, 0, NULL);
	xfs_iunlock(ip, XFS_ILOCK_EXCL);
	return 0;
	}

	/*
	* Handle logging requirements of various synchronous types of write.
	*/
	int
	xfs_write_sync_logforce(
	xfs_mount_t *mp,
	xfs_inode_t *ip)
	{
	int error = 0;

	/*
	* If we're treating this as O_DSYNC and we have not updated the
	* size, force the log.
	*/
	if (!(mp->m_flags & XFS_MOUNT_OSYNCISOSYNC) &&
	!(ip->i_update_size)) {
	xfs_inode_log_item_t *iip = ip->i_itemp;

	/*
	* If an allocation transaction occurred
	* without extending the size, then we have to force
	* the log up the proper point to ensure that the
	* allocation is permanent. We can't count on
	* the fact that buffered writes lock out direct I/O
	* writes - the direct I/O write could have extended
	* the size nontransactionally, then finished before
	* we started. xfs_write_file will think that the file
	* didn't grow but the update isn't safe unless the
	* size change is logged.
	*
	* Force the log if we've committed a transaction
	* against the inode or if someone else has and
	* the commit record hasn't gone to disk (e.g.
	* the inode is pinned). This guarantees that
	* all changes affecting the inode are permanent
	* when we return.
	*/
	if (iip && iip->ili_last_lsn) {
	xfs_log_force(mp, iip->ili_last_lsn,
	XFS_LOG_FORCE \| XFS_LOG_SYNC);
	} else if (xfs_ipincount(ip) > 0) {
	xfs_log_force(mp, (xfs_lsn_t)0,
	XFS_LOG_FORCE \| XFS_LOG_SYNC);
	}

	} else {
	xfs_trans_t *tp;

	/*
	* O_SYNC or O_DSYNC _with_ a size update are handled
	* the same way.
	*
	* If the write was synchronous then we need to make
	* sure that the inode modification time is permanent.
	* We'll have updated the timestamp above, so here
	* we use a synchronous transaction to log the inode.
	* It's not fast, but it's necessary.
	*
	* If this a dsync write and the size got changed
	* non-transactionally, then we need to ensure that
	* the size change gets logged in a synchronous
	* transaction.
	*/
	tp = xfs_trans_alloc(mp, XFS_TRANS_WRITE_SYNC);
	if ((error = xfs_trans_reserve(tp, 0,
	XFS_SWRITE_LOG_RES(mp),
	0, 0, 0))) {
	/* Transaction reserve failed */
	xfs_trans_cancel(tp, 0);
	} else {
	/* Transaction reserve successful */
	xfs_ilock(ip, XFS_ILOCK_EXCL);
	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
	xfs_trans_ihold(tp, ip);
	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
	xfs_trans_set_sync(tp);
	error = xfs_trans_commit(tp, 0, NULL);
	xfs_iunlock(ip, XFS_ILOCK_EXCL);
	}
	}

	return error;
	}

	/*
	* Force a shutdown of the filesystem instantly while keeping
	* the filesystem consistent. We don't do an unmount here; just shutdown
	* the shop, make sure that absolutely nothing persistent happens to
	* this filesystem after this point.
	*/

	void
	xfs_do_force_shutdown(
	bhv_desc_t *bdp,
	int flags,
	char *fname,
	int lnnum)
	{
	int logerror;
	xfs_mount_t *mp;

	mp = XFS_BHVTOM(bdp);
	logerror = flags & SHUTDOWN_LOG_IO_ERROR;

	if (!(flags & SHUTDOWN_FORCE_UMOUNT)) {
	cmn_err(CE_NOTE, "xfs_force_shutdown(%s,0x%x) called from "
	"line %d of file %s. Return address = 0x%p",
	mp->m_fsname, flags, lnnum, fname, __return_address);
	}
	/*
	* No need to duplicate efforts.
	*/
	if (XFS_FORCED_SHUTDOWN(mp) && !logerror)
	return;

	/*
	* This flags XFS_MOUNT_FS_SHUTDOWN, makes sure that we don't
	* queue up anybody new on the log reservations, and wakes up
	* everybody who's sleeping on log reservations to tell them
	* the bad news.
	*/
	if (xfs_log_force_umount(mp, logerror))
	return;

	if (flags & SHUTDOWN_CORRUPT_INCORE) {
	xfs_cmn_err(XFS_PTAG_SHUTDOWN_CORRUPT, CE_ALERT, mp,
	"Corruption of in-memory data detected. Shutting down filesystem: %s",
	mp->m_fsname);
	if (XFS_ERRLEVEL_HIGH <= xfs_error_level) {
	xfs_stack_trace();
	}
	} else if (!(flags & SHUTDOWN_FORCE_UMOUNT)) {
	if (logerror) {
	xfs_cmn_err(XFS_PTAG_SHUTDOWN_LOGERROR, CE_ALERT, mp,
	"Log I/O Error Detected. Shutting down filesystem: %s",
	mp->m_fsname);
	} else if (flags & SHUTDOWN_DEVICE_REQ) {
	xfs_cmn_err(XFS_PTAG_SHUTDOWN_IOERROR, CE_ALERT, mp,
	"All device paths lost. Shutting down filesystem: %s",
	mp->m_fsname);
	} else if (!(flags & SHUTDOWN_REMOTE_REQ)) {
	xfs_cmn_err(XFS_PTAG_SHUTDOWN_IOERROR, CE_ALERT, mp,
	"I/O Error Detected. Shutting down filesystem: %s",
	mp->m_fsname);
	}
	}
	if (!(flags & SHUTDOWN_FORCE_UMOUNT)) {
	cmn_err(CE_ALERT, "Please umount the filesystem, "
	"and rectify the problem(s)");
	}
	}


	/*
	* Called when we want to stop a buffer from getting written or read.
	* We attach the EIO error, muck with its flags, and call biodone
	* so that the proper iodone callbacks get called.
	*/
	int
	xfs_bioerror(
	xfs_buf_t *bp)
	{

	#ifdef XFSERRORDEBUG
	ASSERT(XFS_BUF_ISREAD(bp) \|\| bp->b_iodone);
	#endif

	/*
	* No need to wait until the buffer is unpinned.
	* We aren't flushing it.
	*/
	xfs_buftrace("XFS IOERROR", bp);
	XFS_BUF_ERROR(bp, EIO);
	/*
	* We're calling biodone, so delete B_DONE flag. Either way
	* we have to call the iodone callback, and calling biodone
	* probably is the best way since it takes care of
	* GRIO as well.
	*/
	XFS_BUF_UNREAD(bp);
	XFS_BUF_UNDELAYWRITE(bp);
	XFS_BUF_UNDONE(bp);
	XFS_BUF_STALE(bp);

	XFS_BUF_CLR_BDSTRAT_FUNC(bp);
	xfs_biodone(bp);

	return (EIO);
	}

	/*
	* Same as xfs_bioerror, except that we are releasing the buffer
	* here ourselves, and avoiding the biodone call.
	* This is meant for userdata errors; metadata bufs come with
	* iodone functions attached, so that we can track down errors.
	*/
	int
	xfs_bioerror_relse(
	xfs_buf_t *bp)
	{
	int64_t fl;

	ASSERT(XFS_BUF_IODONE_FUNC(bp) != xfs_buf_iodone_callbacks);
	ASSERT(XFS_BUF_IODONE_FUNC(bp) != xlog_iodone);

	xfs_buftrace("XFS IOERRELSE", bp);
	fl = XFS_BUF_BFLAGS(bp);
	/*
	* No need to wait until the buffer is unpinned.
	* We aren't flushing it.
	*
	* chunkhold expects B_DONE to be set, whether
	* we actually finish the I/O or not. We don't want to
	* change that interface.
	*/
	XFS_BUF_UNREAD(bp);
	XFS_BUF_UNDELAYWRITE(bp);
	XFS_BUF_DONE(bp);
	XFS_BUF_STALE(bp);
	XFS_BUF_CLR_IODONE_FUNC(bp);
	XFS_BUF_CLR_BDSTRAT_FUNC(bp);
	if (!(fl & XFS_B_ASYNC)) {
	/*
	* Mark b_error and B_ERROR _both_.
	* Lot's of chunkcache code assumes that.
	* There's no reason to mark error for
	* ASYNC buffers.
	*/
	XFS_BUF_ERROR(bp, EIO);
	XFS_BUF_V_IODONESEMA(bp);
	} else {
	xfs_buf_relse(bp);
	}
	return (EIO);
	}

	/*
	* Prints out an ALERT message about I/O error.
	*/
	void
	xfs_ioerror_alert(
	char *func,
	struct xfs_mount *mp,
	xfs_buf_t *bp,
	xfs_daddr_t blkno)
	{
	cmn_err(CE_ALERT,
	"I/O error in filesystem (\"%s\") meta-data dev %s block 0x%llx"
	" (\"%s\") error %d buf count %zd",
	(!mp \|\| !mp->m_fsname) ? "(fs name not set)" : mp->m_fsname,
	XFS_BUFTARG_NAME(XFS_BUF_TARGET(bp)),
	(__uint64_t)blkno, func,
	XFS_BUF_GETERROR(bp), XFS_BUF_COUNT(bp));
	}

	/*
	* This isn't an absolute requirement, but it is
	* just a good idea to call xfs_read_buf instead of
	* directly doing a read_buf call. For one, we shouldn't
	* be doing this disk read if we are in SHUTDOWN state anyway,
	* so this stops that from happening. Secondly, this does all
	* the error checking stuff and the brelse if appropriate for
	* the caller, so the code can be a little leaner.
	*/

	int
	xfs_read_buf(
	struct xfs_mount *mp,
	xfs_buftarg_t *target,
	xfs_daddr_t blkno,
	int len,
	uint flags,
	xfs_buf_t **bpp)
	{
	xfs_buf_t *bp;
	int error;

	if (flags)
	bp = xfs_buf_read_flags(target, blkno, len, flags);
	else
	bp = xfs_buf_read(target, blkno, len, flags);
	if (!bp)
	return XFS_ERROR(EIO);
	error = XFS_BUF_GETERROR(bp);
	if (bp && !error && !XFS_FORCED_SHUTDOWN(mp)) {
	*bpp = bp;
	} else {
	*bpp = NULL;
	if (error) {
	xfs_ioerror_alert("xfs_read_buf", mp, bp, XFS_BUF_ADDR(bp));
	} else {
	error = XFS_ERROR(EIO);
	}
	if (bp) {
	XFS_BUF_UNDONE(bp);
	XFS_BUF_UNDELAYWRITE(bp);
	XFS_BUF_STALE(bp);
	/*
	* brelse clears B_ERROR and b_error
	*/
	xfs_buf_relse(bp);
	}
	}
	return (error);
	}

	/*
	* Wrapper around bwrite() so that we can trap
	* write errors, and act accordingly.
	*/
	int
	xfs_bwrite(
	struct xfs_mount *mp,
	struct xfs_buf *bp)
	{
	int error;

	/*
	* XXXsup how does this work for quotas.
	*/
	XFS_BUF_SET_BDSTRAT_FUNC(bp, xfs_bdstrat_cb);
	XFS_BUF_SET_FSPRIVATE3(bp, mp);
	XFS_BUF_WRITE(bp);

	if ((error = XFS_bwrite(bp))) {
	ASSERT(mp);
	/*
	* Cannot put a buftrace here since if the buffer is not
	* B_HOLD then we will brelse() the buffer before returning
	* from bwrite and we could be tracing a buffer that has
	* been reused.
	*/
	xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR);
	}
	return (error);
	}