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

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diff -urN linux-2.4.24/fs/xfs/xfs_utils.c linux-2.4.25/fs/xfs/xfs_utils.c
@@ -0,0 +1,488 @@
+/*
+ * 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_sb.h"
+#include "xfs_dir.h"
+#include "xfs_dir2.h"
+#include "xfs_dmapi.h"
+#include "xfs_mount.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_attr_sf.h"
+#include "xfs_dir_sf.h"
+#include "xfs_dir2_sf.h"
+#include "xfs_dinode.h"
+#include "xfs_inode_item.h"
+#include "xfs_inode.h"
+#include "xfs_bmap.h"
+#include "xfs_error.h"
+#include "xfs_quota.h"
+#include "xfs_rw.h"
+#include "xfs_itable.h"
+#include "xfs_utils.h"
+
+/*
+ * xfs_get_dir_entry is used to get a reference to an inode given
+ * its parent directory inode and the name of the file.	 It does
+ * not lock the child inode, and it unlocks the directory before
+ * returning.  The directory's generation number is returned for
+ * use by a later call to xfs_lock_dir_and_entry.
+ */
+int
+xfs_get_dir_entry(
+	vname_t		*dentry,
+	xfs_inode_t	**ipp)
+{
+	vnode_t		*vp;
+	bhv_desc_t	*bdp;
+
+	vp = VNAME_TO_VNODE(dentry);
+	bdp = vn_bhv_lookup_unlocked(VN_BHV_HEAD(vp), &xfs_vnodeops);
+	if (!bdp) {
+		*ipp = NULL;
+		return XFS_ERROR(ENOENT);
+	}
+	VN_HOLD(vp);
+	*ipp = XFS_BHVTOI(bdp);
+	return 0;
+}
+
+int
+xfs_dir_lookup_int(
+	bhv_desc_t	*dir_bdp,
+	uint		lock_mode,
+	vname_t		*dentry,
+	xfs_ino_t	*inum,
+	xfs_inode_t	**ipp)
+{
+	vnode_t		*dir_vp;
+	xfs_inode_t	*dp;
+	int		error;
+
+	dir_vp = BHV_TO_VNODE(dir_bdp);
+	vn_trace_entry(dir_vp, __FUNCTION__, (inst_t *)__return_address);
+
+	dp = XFS_BHVTOI(dir_bdp);
+
+	error = XFS_DIR_LOOKUP(dp->i_mount, NULL, dp,
+				VNAME(dentry), VNAMELEN(dentry), inum);
+	if (!error) {
+		/*
+		 * Unlock the directory. We do this because we can't
+		 * hold the directory lock while doing the vn_get()
+		 * in xfs_iget().  Doing so could cause us to hold
+		 * a lock while waiting for the inode to finish
+		 * being inactive while it's waiting for a log
+		 * reservation in the inactive routine.
+		 */
+		xfs_iunlock(dp, lock_mode);
+		error = xfs_iget(dp->i_mount, NULL, *inum, 0, ipp, 0);
+		xfs_ilock(dp, lock_mode);
+
+		if (error) {
+			*ipp = NULL;
+		} else if ((*ipp)->i_d.di_mode == 0) {
+			/*
+			 * The inode has been freed.  Something is
+			 * wrong so just get out of here.
+			 */
+			xfs_iunlock(dp, lock_mode);
+			xfs_iput_new(*ipp, 0);
+			*ipp = NULL;
+			xfs_ilock(dp, lock_mode);
+			error = XFS_ERROR(ENOENT);
+		}
+	}
+	return error;
+}
+
+/*
+ * Allocates a new inode from disk and return a pointer to the
+ * incore copy. This routine will internally commit the current
+ * transaction and allocate a new one if the Space Manager needed
+ * to do an allocation to replenish the inode free-list.
+ *
+ * This routine is designed to be called from xfs_create and
+ * xfs_create_dir.
+ *
+ */
+int
+xfs_dir_ialloc(
+	xfs_trans_t	**tpp,		/* input: current transaction;
+					   output: may be a new transaction. */
+	xfs_inode_t	*dp,		/* directory within whose allocate
+					   the inode. */
+	mode_t		mode,
+	nlink_t		nlink,
+	xfs_dev_t	rdev,
+	cred_t		*credp,
+	prid_t		prid,		/* project id */
+	int		okalloc,	/* ok to allocate new space */
+	xfs_inode_t	**ipp,		/* pointer to inode; it will be
+					   locked. */
+	int		*committed)
+
+{
+	xfs_trans_t	*tp;
+	xfs_trans_t	*ntp;
+	xfs_inode_t	*ip;
+	xfs_buf_t	*ialloc_context = NULL;
+	boolean_t	call_again = B_FALSE;
+	int		code;
+	uint		log_res;
+	uint		log_count;
+	void		*dqinfo;
+	uint		tflags;
+
+	tp = *tpp;
+	ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
+
+	/*
+	 * xfs_ialloc will return a pointer to an incore inode if
+	 * the Space Manager has an available inode on the free
+	 * list. Otherwise, it will do an allocation and replenish
+	 * the freelist.  Since we can only do one allocation per
+	 * transaction without deadlocks, we will need to commit the
+	 * current transaction and start a new one.  We will then
+	 * need to call xfs_ialloc again to get the inode.
+	 *
+	 * If xfs_ialloc did an allocation to replenish the freelist,
+	 * it returns the bp containing the head of the freelist as
+	 * ialloc_context. We will hold a lock on it across the
+	 * transaction commit so that no other process can steal
+	 * the inode(s) that we've just allocated.
+	 */
+	code = xfs_ialloc(tp, dp, mode, nlink, rdev, credp, prid, okalloc,
+			  &ialloc_context, &call_again, &ip);
+
+	/*
+	 * Return an error if we were unable to allocate a new inode.
+	 * This should only happen if we run out of space on disk or
+	 * encounter a disk error.
+	 */
+	if (code) {
+		*ipp = NULL;
+		return code;
+	}
+	if (!call_again && (ip == NULL)) {
+		*ipp = NULL;
+		return XFS_ERROR(ENOSPC);
+	}
+
+	/*
+	 * If call_again is set, then we were unable to get an
+	 * inode in one operation.  We need to commit the current
+	 * transaction and call xfs_ialloc() again.  It is guaranteed
+	 * to succeed the second time.
+	 */
+	if (call_again) {
+
+		/*
+		 * Normally, xfs_trans_commit releases all the locks.
+		 * We call bhold to hang on to the ialloc_context across
+		 * the commit.  Holding this buffer prevents any other
+		 * processes from doing any allocations in this
+		 * allocation group.
+		 */
+		xfs_trans_bhold(tp, ialloc_context);
+		/*
+		 * Save the log reservation so we can use
+		 * them in the next transaction.
+		 */
+		log_res = xfs_trans_get_log_res(tp);
+		log_count = xfs_trans_get_log_count(tp);
+
+		/*
+		 * We want the quota changes to be associated with the next
+		 * transaction, NOT this one. So, detach the dqinfo from this
+		 * and attach it to the next transaction.
+		 */
+		dqinfo = NULL;
+		tflags = 0;
+		if (tp->t_dqinfo) {
+			dqinfo = (void *)tp->t_dqinfo;
+			tp->t_dqinfo = NULL;
+			tflags = tp->t_flags & XFS_TRANS_DQ_DIRTY;
+			tp->t_flags &= ~(XFS_TRANS_DQ_DIRTY);
+		}
+
+		ntp = xfs_trans_dup(tp);
+		code = xfs_trans_commit(tp, 0, NULL);
+		tp = ntp;
+		if (committed != NULL) {
+			*committed = 1;
+		}
+		/*
+		 * If we get an error during the commit processing,
+		 * release the buffer that is still held and return
+		 * to the caller.
+		 */
+		if (code) {
+			xfs_buf_relse(ialloc_context);
+			if (dqinfo) {
+				tp->t_dqinfo = dqinfo;
+				XFS_TRANS_FREE_DQINFO(tp->t_mountp, tp);
+			}
+			*tpp = ntp;
+			*ipp = NULL;
+			return code;
+		}
+		code = xfs_trans_reserve(tp, 0, log_res, 0,
+					 XFS_TRANS_PERM_LOG_RES, log_count);
+		/*
+		 * Re-attach the quota info that we detached from prev trx.
+		 */
+		if (dqinfo) {
+			tp->t_dqinfo = dqinfo;
+			tp->t_flags |= tflags;
+		}
+
+		if (code) {
+			xfs_buf_relse(ialloc_context);
+			*tpp = ntp;
+			*ipp = NULL;
+			return code;
+		}
+		xfs_trans_bjoin(tp, ialloc_context);
+
+		/*
+		 * Call ialloc again. Since we've locked out all
+		 * other allocations in this allocation group,
+		 * this call should always succeed.
+		 */
+		code = xfs_ialloc(tp, dp, mode, nlink, rdev, credp, prid,
+				  okalloc, &ialloc_context, &call_again, &ip);
+
+		/*
+		 * If we get an error at this point, return to the caller
+		 * so that the current transaction can be aborted.
+		 */
+		if (code) {
+			*tpp = tp;
+			*ipp = NULL;
+			return code;
+		}
+		ASSERT ((!call_again) && (ip != NULL));
+
+	} else {
+		if (committed != NULL) {
+			*committed = 0;
+		}
+	}
+
+	*ipp = ip;
+	*tpp = tp;
+
+	return 0;
+}
+
+/*
+ * Decrement the link count on an inode & log the change.
+ * If this causes the link count to go to zero, initiate the
+ * logging activity required to truncate a file.
+ */
+int				/* error */
+xfs_droplink(
+	xfs_trans_t *tp,
+	xfs_inode_t *ip)
+{
+	int	error;
+
+	xfs_ichgtime(ip, XFS_ICHGTIME_CHG);
+
+	ASSERT (ip->i_d.di_nlink > 0);
+	ip->i_d.di_nlink--;
+	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+
+	error = 0;
+	if (ip->i_d.di_nlink == 0) {
+		/*
+		 * We're dropping the last link to this file.
+		 * Move the on-disk inode to the AGI unlinked list.
+		 * From xfs_inactive() we will pull the inode from
+		 * the list and free it.
+		 */
+		error = xfs_iunlink(tp, ip);
+	}
+	return error;
+}
+
+/*
+ * This gets called when the inode's version needs to be changed from 1 to 2.
+ * Currently this happens when the nlink field overflows the old 16-bit value
+ * or when chproj is called to change the project for the first time.
+ * As a side effect the superblock version will also get rev'd
+ * to contain the NLINK bit.
+ */
+void
+xfs_bump_ino_vers2(
+	xfs_trans_t	*tp,
+	xfs_inode_t	*ip)
+{
+	xfs_mount_t	*mp;
+	unsigned long		s;
+
+	ASSERT(ismrlocked (&ip->i_lock, MR_UPDATE));
+	ASSERT(ip->i_d.di_version == XFS_DINODE_VERSION_1);
+
+	ip->i_d.di_version = XFS_DINODE_VERSION_2;
+	ip->i_d.di_onlink = 0;
+	memset(&(ip->i_d.di_pad[0]), 0, sizeof(ip->i_d.di_pad));
+	mp = tp->t_mountp;
+	if (!XFS_SB_VERSION_HASNLINK(&mp->m_sb)) {
+		s = XFS_SB_LOCK(mp);
+		if (!XFS_SB_VERSION_HASNLINK(&mp->m_sb)) {
+			XFS_SB_VERSION_ADDNLINK(&mp->m_sb);
+			XFS_SB_UNLOCK(mp, s);
+			xfs_mod_sb(tp, XFS_SB_VERSIONNUM);
+		} else {
+			XFS_SB_UNLOCK(mp, s);
+		}
+	}
+	/* Caller must log the inode */
+}
+
+/*
+ * Increment the link count on an inode & log the change.
+ */
+int
+xfs_bumplink(
+	xfs_trans_t *tp,
+	xfs_inode_t *ip)
+{
+	if (ip->i_d.di_nlink >= XFS_MAXLINK)
+		return XFS_ERROR(EMLINK);
+	xfs_ichgtime(ip, XFS_ICHGTIME_CHG);
+
+	ASSERT(ip->i_d.di_nlink > 0);
+	ip->i_d.di_nlink++;
+	if ((ip->i_d.di_version == XFS_DINODE_VERSION_1) &&
+	    (ip->i_d.di_nlink > XFS_MAXLINK_1)) {
+		/*
+		 * The inode has increased its number of links beyond
+		 * what can fit in an old format inode.  It now needs
+		 * to be converted to a version 2 inode with a 32 bit
+		 * link count.  If this is the first inode in the file
+		 * system to do this, then we need to bump the superblock
+		 * version number as well.
+		 */
+		xfs_bump_ino_vers2(tp, ip);
+	}
+
+	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+	return 0;
+}
+
+/*
+ * Try to truncate the given file to 0 length.  Currently called
+ * only out of xfs_remove when it has to truncate a file to free
+ * up space for the remove to proceed.
+ */
+int
+xfs_truncate_file(
+	xfs_mount_t	*mp,
+	xfs_inode_t	*ip)
+{
+	xfs_trans_t	*tp;
+	int		error;
+
+#ifdef QUOTADEBUG
+	/*
+	 * This is called to truncate the quotainodes too.
+	 */
+	if (XFS_IS_UQUOTA_ON(mp)) {
+		if (ip->i_ino != mp->m_sb.sb_uquotino)
+			ASSERT(ip->i_udquot);
+	}
+	if (XFS_IS_GQUOTA_ON(mp)) {
+		if (ip->i_ino != mp->m_sb.sb_gquotino)
+			ASSERT(ip->i_gdquot);
+	}
+#endif
+	/*
+	 * Make the call to xfs_itruncate_start before starting the
+	 * transaction, because we cannot make the call while we're
+	 * in a transaction.
+	 */
+	xfs_ilock(ip, XFS_IOLOCK_EXCL);
+	xfs_itruncate_start(ip, XFS_ITRUNC_DEFINITE, (xfs_fsize_t)0);
+
+	tp = xfs_trans_alloc(mp, XFS_TRANS_TRUNCATE_FILE);
+	if ((error = xfs_trans_reserve(tp, 0, XFS_ITRUNCATE_LOG_RES(mp), 0,
+				      XFS_TRANS_PERM_LOG_RES,
+				      XFS_ITRUNCATE_LOG_COUNT))) {
+		xfs_trans_cancel(tp, 0);
+		xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+		return error;
+	}
+
+	/*
+	 * Follow the normal truncate locking protocol.  Since we
+	 * hold the inode in the transaction, we know that it's number
+	 * of references will stay constant.
+	 */
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
+	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
+	xfs_trans_ihold(tp, ip);
+	/*
+	 * Signal a sync xaction.  The only case where that isn't
+	 * the case is if we're truncating an already unlinked file
+	 * on a wsync fs.  In that case, we know the blocks can't
+	 * reappear in the file because the links to file are
+	 * permanently toast.  Currently, we're always going to
+	 * want a sync transaction because this code is being
+	 * called from places where nlink is guaranteed to be 1
+	 * but I'm leaving the tests in to protect against future
+	 * changes -- rcc.
+	 */
+	error = xfs_itruncate_finish(&tp, ip, (xfs_fsize_t)0,
+				     XFS_DATA_FORK,
+				     ((ip->i_d.di_nlink != 0 ||
+				       !(mp->m_flags & XFS_MOUNT_WSYNC))
+				      ? 1 : 0));
+	if (error) {
+		xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES |
+				 XFS_TRANS_ABORT);
+	} else {
+		xfs_ichgtime(ip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
+		error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES,
+					 NULL);
+	}
+	xfs_iunlock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
+
+	return error;
+}

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