[linux.git] / fs / xfs / xfs_utils.c

/*
 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_inode_item.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"


/*
 * 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,
	xfs_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);
		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--;
	drop_nlink(VFS_I(ip));
	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;

	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
	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)) {
		spin_lock(&mp->m_sb_lock);
		if (!xfs_sb_version_hasnlink(&mp->m_sb)) {
			xfs_sb_version_addnlink(&mp->m_sb);
			spin_unlock(&mp->m_sb_lock);
			xfs_mod_sb(tp, XFS_SB_VERSIONNUM);
		} else {
			spin_unlock(&mp->m_sb_lock);
		}
	}
	/* 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++;
	inc_nlink(VFS_I(ip));
	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_OQUOTA_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);
	error = xfs_itruncate_start(ip, XFS_ITRUNC_DEFINITE, (xfs_fsize_t)0);
	if (error) {
		xfs_iunlock(ip, XFS_IOLOCK_EXCL);
		return error;
	}

	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);
	}
	xfs_iunlock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);

	return error;
}
Commit	Line	Data
1da177e4	1	/*
7b718769 NS	2	* Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
7b718769 NS	3	* All Rights Reserved.
1da177e4	4	*
7b718769 NS	5	* This program is free software; you can redistribute it and/or
7b718769 NS	6	* modify it under the terms of the GNU General Public License as
1da177e4 LT	7	* published by the Free Software Foundation.
1da177e4 LT	8	*
7b718769 NS	9	* This program is distributed in the hope that it would be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
1da177e4	13	*
7b718769 NS	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, write the Free Software Foundation,
	16	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
1da177e4	17	*/
1da177e4	18	#include "xfs.h"
a844f451	19	#include "xfs_fs.h"
1da177e4	20	#include "xfs_types.h"
a844f451	21	#include "xfs_bit.h"
1da177e4	22	#include "xfs_log.h"
a844f451	23	#include "xfs_inum.h"
1da177e4 LT	24	#include "xfs_trans.h"
1da177e4 LT	25	#include "xfs_sb.h"
a844f451	26	#include "xfs_ag.h"
1da177e4 LT	27	#include "xfs_dir2.h"
	28	#include "xfs_dmapi.h"
	29	#include "xfs_mount.h"
	30	#include "xfs_bmap_btree.h"
1da177e4	31	#include "xfs_dir2_sf.h"
a844f451	32	#include "xfs_attr_sf.h"
1da177e4	33	#include "xfs_dinode.h"
1da177e4	34	#include "xfs_inode.h"
a844f451	35	#include "xfs_inode_item.h"
1da177e4 LT	36	#include "xfs_bmap.h"
	37	#include "xfs_error.h"
	38	#include "xfs_quota.h"
	39	#include "xfs_rw.h"
	40	#include "xfs_itable.h"
	41	#include "xfs_utils.h"
	42
1da177e4	43
1da177e4 LT	44	/*
	45	* Allocates a new inode from disk and return a pointer to the
	46	* incore copy. This routine will internally commit the current
	47	* transaction and allocate a new one if the Space Manager needed
	48	* to do an allocation to replenish the inode free-list.
	49	*
	50	* This routine is designed to be called from xfs_create and
	51	* xfs_create_dir.
	52	*
	53	*/
	54	int
	55	xfs_dir_ialloc(
	56	xfs_trans_t *tpp, / input: current transaction;
	57	output: may be a new transaction. */
	58	xfs_inode_t dp, / directory within whose allocate
	59	the inode. */
	60	mode_t mode,
31b084ae	61	xfs_nlink_t nlink,
1da177e4 LT	62	xfs_dev_t rdev,
	63	cred_t *credp,
	64	prid_t prid, /* project id */
	65	int okalloc, /* ok to allocate new space */
	66	xfs_inode_t *ipp, / pointer to inode; it will be
	67	locked. */
	68	int *committed)
	69
	70	{
	71	xfs_trans_t *tp;
	72	xfs_trans_t *ntp;
	73	xfs_inode_t *ip;
	74	xfs_buf_t *ialloc_context = NULL;
	75	boolean_t call_again = B_FALSE;
	76	int code;
	77	uint log_res;
	78	uint log_count;
	79	void *dqinfo;
	80	uint tflags;
	81
	82	tp = *tpp;
	83	ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
	84
	85	/*
	86	* xfs_ialloc will return a pointer to an incore inode if
	87	* the Space Manager has an available inode on the free
	88	* list. Otherwise, it will do an allocation and replenish
	89	* the freelist. Since we can only do one allocation per
	90	* transaction without deadlocks, we will need to commit the
	91	* current transaction and start a new one. We will then
	92	* need to call xfs_ialloc again to get the inode.
	93	*
	94	* If xfs_ialloc did an allocation to replenish the freelist,
	95	* it returns the bp containing the head of the freelist as
	96	* ialloc_context. We will hold a lock on it across the
	97	* transaction commit so that no other process can steal
	98	* the inode(s) that we've just allocated.
	99	*/
	100	code = xfs_ialloc(tp, dp, mode, nlink, rdev, credp, prid, okalloc,
	101	&ialloc_context, &call_again, &ip);
	102
	103	/*
	104	* Return an error if we were unable to allocate a new inode.
	105	* This should only happen if we run out of space on disk or
	106	* encounter a disk error.
	107	*/
	108	if (code) {
	109	*ipp = NULL;
	110	return code;
	111	}
	112	if (!call_again && (ip == NULL)) {
	113	*ipp = NULL;
	114	return XFS_ERROR(ENOSPC);
	115	}
	116
	117	/*
	118	* If call_again is set, then we were unable to get an
	119	* inode in one operation. We need to commit the current
	120	* transaction and call xfs_ialloc() again. It is guaranteed
	121	* to succeed the second time.
	122	*/
	123	if (call_again) {
	124
	125	/*
126	* Normally, xfs_trans_commit releases all the locks.
127	* We call bhold to hang on to the ialloc_context across
128	* the commit. Holding this buffer prevents any other
129	* processes from doing any allocations in this
130	* allocation group.
131	*/
132	xfs_trans_bhold(tp, ialloc_context);
133	/*
134	* Save the log reservation so we can use
135	* them in the next transaction.
136	*/
137	log_res = xfs_trans_get_log_res(tp);
138	log_count = xfs_trans_get_log_count(tp);
139
140	/*
141	* We want the quota changes to be associated with the next
142	* transaction, NOT this one. So, detach the dqinfo from this
143	* and attach it to the next transaction.
144	*/
145	dqinfo = NULL;
146	tflags = 0;
147	if (tp->t_dqinfo) {
148	dqinfo = (void *)tp->t_dqinfo;
149	tp->t_dqinfo = NULL;
150	tflags = tp->t_flags & XFS_TRANS_DQ_DIRTY;
151	tp->t_flags &= ~(XFS_TRANS_DQ_DIRTY);
152	}
153
154	ntp = xfs_trans_dup(tp);
1c72bf90	155	code = xfs_trans_commit(tp, 0);
1da177e4 LT	156	tp = ntp;
	157	if (committed != NULL) {
	158	*committed = 1;
	159	}
	160	/*
	161	* If we get an error during the commit processing,
	162	* release the buffer that is still held and return
	163	* to the caller.
	164	*/
	165	if (code) {
	166	xfs_buf_relse(ialloc_context);
	167	if (dqinfo) {
	168	tp->t_dqinfo = dqinfo;
	169	XFS_TRANS_FREE_DQINFO(tp->t_mountp, tp);
	170	}
	171	*tpp = ntp;
	172	*ipp = NULL;
	173	return code;
	174	}
	175	code = xfs_trans_reserve(tp, 0, log_res, 0,
	176	XFS_TRANS_PERM_LOG_RES, log_count);
	177	/*
	178	* Re-attach the quota info that we detached from prev trx.
	179	*/
	180	if (dqinfo) {
	181	tp->t_dqinfo = dqinfo;
	182	tp->t_flags \|= tflags;
	183	}
	184
	185	if (code) {
	186	xfs_buf_relse(ialloc_context);
	187	*tpp = ntp;
	188	*ipp = NULL;
	189	return code;
	190	}
	191	xfs_trans_bjoin(tp, ialloc_context);
	192
	193	/*
	194	* Call ialloc again. Since we've locked out all
	195	* other allocations in this allocation group,
	196	* this call should always succeed.
	197	*/
	198	code = xfs_ialloc(tp, dp, mode, nlink, rdev, credp, prid,
	199	okalloc, &ialloc_context, &call_again, &ip);
	200
	201	/*
	202	* If we get an error at this point, return to the caller
	203	* so that the current transaction can be aborted.
	204	*/
	205	if (code) {
	206	*tpp = tp;
	207	*ipp = NULL;
	208	return code;
	209	}
	210	ASSERT ((!call_again) && (ip != NULL));
	211
	212	} else {
	213	if (committed != NULL) {
	214	*committed = 0;
	215	}
	216	}
	217
	218	*ipp = ip;
	219	*tpp = tp;
220
221	return 0;
222	}
223
224	/*
225	* Decrement the link count on an inode & log the change.
226	* If this causes the link count to go to zero, initiate the
227	* logging activity required to truncate a file.
228	*/
229	int /* error */
230	xfs_droplink(
231	xfs_trans_t *tp,
232	xfs_inode_t *ip)
233	{
234	int error;
235
236	xfs_ichgtime(ip, XFS_ICHGTIME_CHG);
237
238	ASSERT (ip->i_d.di_nlink > 0);
239	ip->i_d.di_nlink--;
01651646	240	drop_nlink(VFS_I(ip));
1da177e4 LT	241	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
	242
	243	error = 0;
	244	if (ip->i_d.di_nlink == 0) {
	245	/*
	246	* We're dropping the last link to this file.
	247	* Move the on-disk inode to the AGI unlinked list.
	248	* From xfs_inactive() we will pull the inode from
	249	* the list and free it.
	250	*/
	251	error = xfs_iunlink(tp, ip);
	252	}
	253	return error;
	254	}
	255
	256	/*
	257	* This gets called when the inode's version needs to be changed from 1 to 2.
	258	* Currently this happens when the nlink field overflows the old 16-bit value
	259	* or when chproj is called to change the project for the first time.
	260	* As a side effect the superblock version will also get rev'd
	261	* to contain the NLINK bit.
	262	*/
	263	void
	264	xfs_bump_ino_vers2(
	265	xfs_trans_t *tp,
	266	xfs_inode_t *ip)
	267	{
	268	xfs_mount_t *mp;
1da177e4	269
579aa9ca	270	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
1da177e4 LT	271	ASSERT(ip->i_d.di_version == XFS_DINODE_VERSION_1);
	272
	273	ip->i_d.di_version = XFS_DINODE_VERSION_2;
	274	ip->i_d.di_onlink = 0;
	275	memset(&(ip->i_d.di_pad[0]), 0, sizeof(ip->i_d.di_pad));
	276	mp = tp->t_mountp;
62118709	277	if (!xfs_sb_version_hasnlink(&mp->m_sb)) {
3685c2a1	278	spin_lock(&mp->m_sb_lock);
62118709 ES	279	if (!xfs_sb_version_hasnlink(&mp->m_sb)) {
62118709 ES	280	xfs_sb_version_addnlink(&mp->m_sb);
3685c2a1	281	spin_unlock(&mp->m_sb_lock);
1da177e4 LT	282	xfs_mod_sb(tp, XFS_SB_VERSIONNUM);
1da177e4 LT	283	} else {
3685c2a1	284	spin_unlock(&mp->m_sb_lock);
1da177e4 LT	285	}
	286	}
	287	/* Caller must log the inode */
	288	}
	289
	290	/*
	291	* Increment the link count on an inode & log the change.
	292	*/
	293	int
	294	xfs_bumplink(
	295	xfs_trans_t *tp,
	296	xfs_inode_t *ip)
	297	{
	298	if (ip->i_d.di_nlink >= XFS_MAXLINK)
	299	return XFS_ERROR(EMLINK);
	300	xfs_ichgtime(ip, XFS_ICHGTIME_CHG);
	301
	302	ASSERT(ip->i_d.di_nlink > 0);
	303	ip->i_d.di_nlink++;
01651646	304	inc_nlink(VFS_I(ip));
1da177e4 LT	305	if ((ip->i_d.di_version == XFS_DINODE_VERSION_1) &&
	306	(ip->i_d.di_nlink > XFS_MAXLINK_1)) {
	307	/*
	308	* The inode has increased its number of links beyond
	309	* what can fit in an old format inode. It now needs
	310	* to be converted to a version 2 inode with a 32 bit
	311	* link count. If this is the first inode in the file
	312	* system to do this, then we need to bump the superblock
	313	* version number as well.
	314	*/
	315	xfs_bump_ino_vers2(tp, ip);
	316	}
	317
	318	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
	319	return 0;
	320	}
	321
	322	/*
	323	* Try to truncate the given file to 0 length. Currently called
	324	* only out of xfs_remove when it has to truncate a file to free
	325	* up space for the remove to proceed.
	326	*/
	327	int
	328	xfs_truncate_file(
	329	xfs_mount_t *mp,
	330	xfs_inode_t *ip)
	331	{
	332	xfs_trans_t *tp;
	333	int error;
	334
	335	#ifdef QUOTADEBUG
	336	/*
	337	* This is called to truncate the quotainodes too.
	338	*/
	339	if (XFS_IS_UQUOTA_ON(mp)) {
	340	if (ip->i_ino != mp->m_sb.sb_uquotino)
	341	ASSERT(ip->i_udquot);
	342	}
c8ad20ff	343	if (XFS_IS_OQUOTA_ON(mp)) {
1da177e4 LT	344	if (ip->i_ino != mp->m_sb.sb_gquotino)
	345	ASSERT(ip->i_gdquot);
	346	}
	347	#endif
	348	/*
	349	* Make the call to xfs_itruncate_start before starting the
	350	* transaction, because we cannot make the call while we're
	351	* in a transaction.
	352	*/
	353	xfs_ilock(ip, XFS_IOLOCK_EXCL);
d3cf2094 LM	354	error = xfs_itruncate_start(ip, XFS_ITRUNC_DEFINITE, (xfs_fsize_t)0);
	355	if (error) {
	356	xfs_iunlock(ip, XFS_IOLOCK_EXCL);
	357	return error;
	358	}
1da177e4 LT	359
	360	tp = xfs_trans_alloc(mp, XFS_TRANS_TRUNCATE_FILE);
	361	if ((error = xfs_trans_reserve(tp, 0, XFS_ITRUNCATE_LOG_RES(mp), 0,
	362	XFS_TRANS_PERM_LOG_RES,
	363	XFS_ITRUNCATE_LOG_COUNT))) {
	364	xfs_trans_cancel(tp, 0);
	365	xfs_iunlock(ip, XFS_IOLOCK_EXCL);
	366	return error;
	367	}
	368
	369	/*
	370	* Follow the normal truncate locking protocol. Since we
	371	* hold the inode in the transaction, we know that it's number
	372	* of references will stay constant.
	373	*/
	374	xfs_ilock(ip, XFS_ILOCK_EXCL);
	375	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL \| XFS_IOLOCK_EXCL);
	376	xfs_trans_ihold(tp, ip);
	377	/*
	378	* Signal a sync xaction. The only case where that isn't
	379	* the case is if we're truncating an already unlinked file
	380	* on a wsync fs. In that case, we know the blocks can't
	381	* reappear in the file because the links to file are
	382	* permanently toast. Currently, we're always going to
	383	* want a sync transaction because this code is being
	384	* called from places where nlink is guaranteed to be 1
	385	* but I'm leaving the tests in to protect against future
	386	* changes -- rcc.
	387	*/
	388	error = xfs_itruncate_finish(&tp, ip, (xfs_fsize_t)0,
	389	XFS_DATA_FORK,
	390	((ip->i_d.di_nlink != 0 \|\|
	391	!(mp->m_flags & XFS_MOUNT_WSYNC))
	392	? 1 : 0));
	393	if (error) {
	394	xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES \|
	395	XFS_TRANS_ABORT);
	396	} else {
	397	xfs_ichgtime(ip, XFS_ICHGTIME_MOD \| XFS_ICHGTIME_CHG);
1c72bf90	398	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
1da177e4 LT	399	}
	400	xfs_iunlock(ip, XFS_ILOCK_EXCL \| XFS_IOLOCK_EXCL);
	401
	402	return error;
	403	}