Add the rt linux 4.1.3-rt3 as base

Import the rt linux 4.1.3-rt3 as OPNFV kvm base.

It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:

commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Sat Jul 25 12:13:34 2015 +0200

    Prepare v4.1.3-rt3

    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.

Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>

1 files changed, 1104 insertions, 0 deletions

diff --git a/kernel/fs/xfs/xfs_dquot.c b/kernel/fs/xfs/xfs_dquot.c
new file mode 100644
index 000000000..02c01bbbc
--- /dev/null
+++ b/kernel/fs/xfs/xfs_dquot.c
@@ -0,0 +1,1104 @@
+/*
+ * Copyright (c) 2000-2003 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_format.h"
+#include "xfs_log_format.h"
+#include "xfs_shared.h"
+#include "xfs_trans_resv.h"
+#include "xfs_bit.h"
+#include "xfs_mount.h"
+#include "xfs_inode.h"
+#include "xfs_bmap.h"
+#include "xfs_bmap_util.h"
+#include "xfs_alloc.h"
+#include "xfs_quota.h"
+#include "xfs_error.h"
+#include "xfs_trans.h"
+#include "xfs_buf_item.h"
+#include "xfs_trans_space.h"
+#include "xfs_trans_priv.h"
+#include "xfs_qm.h"
+#include "xfs_cksum.h"
+#include "xfs_trace.h"
+#include "xfs_log.h"
+#include "xfs_bmap_btree.h"
+
+/*
+ * Lock order:
+ *
+ * ip->i_lock
+ *   qi->qi_tree_lock
+ *     dquot->q_qlock (xfs_dqlock() and friends)
+ *       dquot->q_flush (xfs_dqflock() and friends)
+ *       qi->qi_lru_lock
+ *
+ * If two dquots need to be locked the order is user before group/project,
+ * otherwise by the lowest id first, see xfs_dqlock2.
+ */
+
+#ifdef DEBUG
+xfs_buftarg_t *xfs_dqerror_target;
+int xfs_do_dqerror;
+int xfs_dqreq_num;
+int xfs_dqerror_mod = 33;
+#endif
+
+struct kmem_zone		*xfs_qm_dqtrxzone;
+static struct kmem_zone		*xfs_qm_dqzone;
+
+static struct lock_class_key xfs_dquot_group_class;
+static struct lock_class_key xfs_dquot_project_class;
+
+/*
+ * This is called to free all the memory associated with a dquot
+ */
+void
+xfs_qm_dqdestroy(
+	xfs_dquot_t	*dqp)
+{
+	ASSERT(list_empty(&dqp->q_lru));
+
+	mutex_destroy(&dqp->q_qlock);
+	kmem_zone_free(xfs_qm_dqzone, dqp);
+
+	XFS_STATS_DEC(xs_qm_dquot);
+}
+
+/*
+ * If default limits are in force, push them into the dquot now.
+ * We overwrite the dquot limits only if they are zero and this
+ * is not the root dquot.
+ */
+void
+xfs_qm_adjust_dqlimits(
+	struct xfs_mount	*mp,
+	struct xfs_dquot	*dq)
+{
+	struct xfs_quotainfo	*q = mp->m_quotainfo;
+	struct xfs_disk_dquot	*d = &dq->q_core;
+	int			prealloc = 0;
+
+	ASSERT(d->d_id);
+
+	if (q->qi_bsoftlimit && !d->d_blk_softlimit) {
+		d->d_blk_softlimit = cpu_to_be64(q->qi_bsoftlimit);
+		prealloc = 1;
+	}
+	if (q->qi_bhardlimit && !d->d_blk_hardlimit) {
+		d->d_blk_hardlimit = cpu_to_be64(q->qi_bhardlimit);
+		prealloc = 1;
+	}
+	if (q->qi_isoftlimit && !d->d_ino_softlimit)
+		d->d_ino_softlimit = cpu_to_be64(q->qi_isoftlimit);
+	if (q->qi_ihardlimit && !d->d_ino_hardlimit)
+		d->d_ino_hardlimit = cpu_to_be64(q->qi_ihardlimit);
+	if (q->qi_rtbsoftlimit && !d->d_rtb_softlimit)
+		d->d_rtb_softlimit = cpu_to_be64(q->qi_rtbsoftlimit);
+	if (q->qi_rtbhardlimit && !d->d_rtb_hardlimit)
+		d->d_rtb_hardlimit = cpu_to_be64(q->qi_rtbhardlimit);
+
+	if (prealloc)
+		xfs_dquot_set_prealloc_limits(dq);
+}
+
+/*
+ * Check the limits and timers of a dquot and start or reset timers
+ * if necessary.
+ * This gets called even when quota enforcement is OFF, which makes our
+ * life a little less complicated. (We just don't reject any quota
+ * reservations in that case, when enforcement is off).
+ * We also return 0 as the values of the timers in Q_GETQUOTA calls, when
+ * enforcement's off.
+ * In contrast, warnings are a little different in that they don't
+ * 'automatically' get started when limits get exceeded.  They do
+ * get reset to zero, however, when we find the count to be under
+ * the soft limit (they are only ever set non-zero via userspace).
+ */
+void
+xfs_qm_adjust_dqtimers(
+	xfs_mount_t		*mp,
+	xfs_disk_dquot_t	*d)
+{
+	ASSERT(d->d_id);
+
+#ifdef DEBUG
+	if (d->d_blk_hardlimit)
+		ASSERT(be64_to_cpu(d->d_blk_softlimit) <=
+		       be64_to_cpu(d->d_blk_hardlimit));
+	if (d->d_ino_hardlimit)
+		ASSERT(be64_to_cpu(d->d_ino_softlimit) <=
+		       be64_to_cpu(d->d_ino_hardlimit));
+	if (d->d_rtb_hardlimit)
+		ASSERT(be64_to_cpu(d->d_rtb_softlimit) <=
+		       be64_to_cpu(d->d_rtb_hardlimit));
+#endif
+
+	if (!d->d_btimer) {
+		if ((d->d_blk_softlimit &&
+		     (be64_to_cpu(d->d_bcount) >
+		      be64_to_cpu(d->d_blk_softlimit))) ||
+		    (d->d_blk_hardlimit &&
+		     (be64_to_cpu(d->d_bcount) >
+		      be64_to_cpu(d->d_blk_hardlimit)))) {
+			d->d_btimer = cpu_to_be32(get_seconds() +
+					mp->m_quotainfo->qi_btimelimit);
+		} else {
+			d->d_bwarns = 0;
+		}
+	} else {
+		if ((!d->d_blk_softlimit ||
+		     (be64_to_cpu(d->d_bcount) <=
+		      be64_to_cpu(d->d_blk_softlimit))) &&
+		    (!d->d_blk_hardlimit ||
+		    (be64_to_cpu(d->d_bcount) <=
+		     be64_to_cpu(d->d_blk_hardlimit)))) {
+			d->d_btimer = 0;
+		}
+	}
+
+	if (!d->d_itimer) {
+		if ((d->d_ino_softlimit &&
+		     (be64_to_cpu(d->d_icount) >
+		      be64_to_cpu(d->d_ino_softlimit))) ||
+		    (d->d_ino_hardlimit &&
+		     (be64_to_cpu(d->d_icount) >
+		      be64_to_cpu(d->d_ino_hardlimit)))) {
+			d->d_itimer = cpu_to_be32(get_seconds() +
+					mp->m_quotainfo->qi_itimelimit);
+		} else {
+			d->d_iwarns = 0;
+		}
+	} else {
+		if ((!d->d_ino_softlimit ||
+		     (be64_to_cpu(d->d_icount) <=
+		      be64_to_cpu(d->d_ino_softlimit)))  &&
+		    (!d->d_ino_hardlimit ||
+		     (be64_to_cpu(d->d_icount) <=
+		      be64_to_cpu(d->d_ino_hardlimit)))) {
+			d->d_itimer = 0;
+		}
+	}
+
+	if (!d->d_rtbtimer) {
+		if ((d->d_rtb_softlimit &&
+		     (be64_to_cpu(d->d_rtbcount) >
+		      be64_to_cpu(d->d_rtb_softlimit))) ||
+		    (d->d_rtb_hardlimit &&
+		     (be64_to_cpu(d->d_rtbcount) >
+		      be64_to_cpu(d->d_rtb_hardlimit)))) {
+			d->d_rtbtimer = cpu_to_be32(get_seconds() +
+					mp->m_quotainfo->qi_rtbtimelimit);
+		} else {
+			d->d_rtbwarns = 0;
+		}
+	} else {
+		if ((!d->d_rtb_softlimit ||
+		     (be64_to_cpu(d->d_rtbcount) <=
+		      be64_to_cpu(d->d_rtb_softlimit))) &&
+		    (!d->d_rtb_hardlimit ||
+		     (be64_to_cpu(d->d_rtbcount) <=
+		      be64_to_cpu(d->d_rtb_hardlimit)))) {
+			d->d_rtbtimer = 0;
+		}
+	}
+}
+
+/*
+ * initialize a buffer full of dquots and log the whole thing
+ */
+STATIC void
+xfs_qm_init_dquot_blk(
+	xfs_trans_t	*tp,
+	xfs_mount_t	*mp,
+	xfs_dqid_t	id,
+	uint		type,
+	xfs_buf_t	*bp)
+{
+	struct xfs_quotainfo	*q = mp->m_quotainfo;
+	xfs_dqblk_t	*d;
+	int		curid, i;
+
+	ASSERT(tp);
+	ASSERT(xfs_buf_islocked(bp));
+
+	d = bp->b_addr;
+
+	/*
+	 * ID of the first dquot in the block - id's are zero based.
+	 */
+	curid = id - (id % q->qi_dqperchunk);
+	ASSERT(curid >= 0);
+	memset(d, 0, BBTOB(q->qi_dqchunklen));
+	for (i = 0; i < q->qi_dqperchunk; i++, d++, curid++) {
+		d->dd_diskdq.d_magic = cpu_to_be16(XFS_DQUOT_MAGIC);
+		d->dd_diskdq.d_version = XFS_DQUOT_VERSION;
+		d->dd_diskdq.d_id = cpu_to_be32(curid);
+		d->dd_diskdq.d_flags = type;
+		if (xfs_sb_version_hascrc(&mp->m_sb)) {
+			uuid_copy(&d->dd_uuid, &mp->m_sb.sb_uuid);
+			xfs_update_cksum((char *)d, sizeof(struct xfs_dqblk),
+					 XFS_DQUOT_CRC_OFF);
+		}
+	}
+
+	xfs_trans_dquot_buf(tp, bp,
+			    (type & XFS_DQ_USER ? XFS_BLF_UDQUOT_BUF :
+			    ((type & XFS_DQ_PROJ) ? XFS_BLF_PDQUOT_BUF :
+			     XFS_BLF_GDQUOT_BUF)));
+	xfs_trans_log_buf(tp, bp, 0, BBTOB(q->qi_dqchunklen) - 1);
+}
+
+/*
+ * Initialize the dynamic speculative preallocation thresholds. The lo/hi
+ * watermarks correspond to the soft and hard limits by default. If a soft limit
+ * is not specified, we use 95% of the hard limit.
+ */
+void
+xfs_dquot_set_prealloc_limits(struct xfs_dquot *dqp)
+{
+	__uint64_t space;
+
+	dqp->q_prealloc_hi_wmark = be64_to_cpu(dqp->q_core.d_blk_hardlimit);
+	dqp->q_prealloc_lo_wmark = be64_to_cpu(dqp->q_core.d_blk_softlimit);
+	if (!dqp->q_prealloc_lo_wmark) {
+		dqp->q_prealloc_lo_wmark = dqp->q_prealloc_hi_wmark;
+		do_div(dqp->q_prealloc_lo_wmark, 100);
+		dqp->q_prealloc_lo_wmark *= 95;
+	}
+
+	space = dqp->q_prealloc_hi_wmark;
+
+	do_div(space, 100);
+	dqp->q_low_space[XFS_QLOWSP_1_PCNT] = space;
+	dqp->q_low_space[XFS_QLOWSP_3_PCNT] = space * 3;
+	dqp->q_low_space[XFS_QLOWSP_5_PCNT] = space * 5;
+}
+
+/*
+ * Allocate a block and fill it with dquots.
+ * This is called when the bmapi finds a hole.
+ */
+STATIC int
+xfs_qm_dqalloc(
+	xfs_trans_t	**tpp,
+	xfs_mount_t	*mp,
+	xfs_dquot_t	*dqp,
+	xfs_inode_t	*quotip,
+	xfs_fileoff_t	offset_fsb,
+	xfs_buf_t	**O_bpp)
+{
+	xfs_fsblock_t	firstblock;
+	xfs_bmap_free_t flist;
+	xfs_bmbt_irec_t map;
+	int		nmaps, error, committed;
+	xfs_buf_t	*bp;
+	xfs_trans_t	*tp = *tpp;
+
+	ASSERT(tp != NULL);
+
+	trace_xfs_dqalloc(dqp);
+
+	/*
+	 * Initialize the bmap freelist prior to calling bmapi code.
+	 */
+	xfs_bmap_init(&flist, &firstblock);
+	xfs_ilock(quotip, XFS_ILOCK_EXCL);
+	/*
+	 * Return if this type of quotas is turned off while we didn't
+	 * have an inode lock
+	 */
+	if (!xfs_this_quota_on(dqp->q_mount, dqp->dq_flags)) {
+		xfs_iunlock(quotip, XFS_ILOCK_EXCL);
+		return -ESRCH;
+	}
+
+	xfs_trans_ijoin(tp, quotip, XFS_ILOCK_EXCL);
+	nmaps = 1;
+	error = xfs_bmapi_write(tp, quotip, offset_fsb,
+				XFS_DQUOT_CLUSTER_SIZE_FSB, XFS_BMAPI_METADATA,
+				&firstblock, XFS_QM_DQALLOC_SPACE_RES(mp),
+				&map, &nmaps, &flist);
+	if (error)
+		goto error0;
+	ASSERT(map.br_blockcount == XFS_DQUOT_CLUSTER_SIZE_FSB);
+	ASSERT(nmaps == 1);
+	ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
+	       (map.br_startblock != HOLESTARTBLOCK));
+
+	/*
+	 * Keep track of the blkno to save a lookup later
+	 */
+	dqp->q_blkno = XFS_FSB_TO_DADDR(mp, map.br_startblock);
+
+	/* now we can just get the buffer (there's nothing to read yet) */
+	bp = xfs_trans_get_buf(tp, mp->m_ddev_targp,
+			       dqp->q_blkno,
+			       mp->m_quotainfo->qi_dqchunklen,
+			       0);
+	if (!bp) {
+		error = -ENOMEM;
+		goto error1;
+	}
+	bp->b_ops = &xfs_dquot_buf_ops;
+
+	/*
+	 * Make a chunk of dquots out of this buffer and log
+	 * the entire thing.
+	 */
+	xfs_qm_init_dquot_blk(tp, mp, be32_to_cpu(dqp->q_core.d_id),
+			      dqp->dq_flags & XFS_DQ_ALLTYPES, bp);
+
+	/*
+	 * xfs_bmap_finish() may commit the current transaction and
+	 * start a second transaction if the freelist is not empty.
+	 *
+	 * Since we still want to modify this buffer, we need to
+	 * ensure that the buffer is not released on commit of
+	 * the first transaction and ensure the buffer is added to the
+	 * second transaction.
+	 *
+	 * If there is only one transaction then don't stop the buffer
+	 * from being released when it commits later on.
+	 */
+
+	xfs_trans_bhold(tp, bp);
+
+	if ((error = xfs_bmap_finish(tpp, &flist, &committed))) {
+		goto error1;
+	}
+
+	if (committed) {
+		tp = *tpp;
+		xfs_trans_bjoin(tp, bp);
+	} else {
+		xfs_trans_bhold_release(tp, bp);
+	}
+
+	*O_bpp = bp;
+	return 0;
+
+      error1:
+	xfs_bmap_cancel(&flist);
+      error0:
+	xfs_iunlock(quotip, XFS_ILOCK_EXCL);
+
+	return error;
+}
+
+STATIC int
+xfs_qm_dqrepair(
+	struct xfs_mount	*mp,
+	struct xfs_trans	*tp,
+	struct xfs_dquot	*dqp,
+	xfs_dqid_t		firstid,
+	struct xfs_buf		**bpp)
+{
+	int			error;
+	struct xfs_disk_dquot	*ddq;
+	struct xfs_dqblk	*d;
+	int			i;
+
+	/*
+	 * Read the buffer without verification so we get the corrupted
+	 * buffer returned to us. make sure we verify it on write, though.
+	 */
+	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, dqp->q_blkno,
+				   mp->m_quotainfo->qi_dqchunklen,
+				   0, bpp, NULL);
+
+	if (error) {
+		ASSERT(*bpp == NULL);
+		return error;
+	}
+	(*bpp)->b_ops = &xfs_dquot_buf_ops;
+
+	ASSERT(xfs_buf_islocked(*bpp));
+	d = (struct xfs_dqblk *)(*bpp)->b_addr;
+
+	/* Do the actual repair of dquots in this buffer */
+	for (i = 0; i < mp->m_quotainfo->qi_dqperchunk; i++) {
+		ddq = &d[i].dd_diskdq;
+		error = xfs_dqcheck(mp, ddq, firstid + i,
+				       dqp->dq_flags & XFS_DQ_ALLTYPES,
+				       XFS_QMOPT_DQREPAIR, "xfs_qm_dqrepair");
+		if (error) {
+			/* repair failed, we're screwed */
+			xfs_trans_brelse(tp, *bpp);
+			return -EIO;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Maps a dquot to the buffer containing its on-disk version.
+ * This returns a ptr to the buffer containing the on-disk dquot
+ * in the bpp param, and a ptr to the on-disk dquot within that buffer
+ */
+STATIC int
+xfs_qm_dqtobp(
+	xfs_trans_t		**tpp,
+	xfs_dquot_t		*dqp,
+	xfs_disk_dquot_t	**O_ddpp,
+	xfs_buf_t		**O_bpp,
+	uint			flags)
+{
+	struct xfs_bmbt_irec	map;
+	int			nmaps = 1, error;
+	struct xfs_buf		*bp;
+	struct xfs_inode	*quotip = xfs_dq_to_quota_inode(dqp);
+	struct xfs_mount	*mp = dqp->q_mount;
+	xfs_dqid_t		id = be32_to_cpu(dqp->q_core.d_id);
+	struct xfs_trans	*tp = (tpp ? *tpp : NULL);
+	uint			lock_mode;
+
+	dqp->q_fileoffset = (xfs_fileoff_t)id / mp->m_quotainfo->qi_dqperchunk;
+
+	lock_mode = xfs_ilock_data_map_shared(quotip);
+	if (!xfs_this_quota_on(dqp->q_mount, dqp->dq_flags)) {
+		/*
+		 * Return if this type of quotas is turned off while we
+		 * didn't have the quota inode lock.
+		 */
+		xfs_iunlock(quotip, lock_mode);
+		return -ESRCH;
+	}
+
+	/*
+	 * Find the block map; no allocations yet
+	 */
+	error = xfs_bmapi_read(quotip, dqp->q_fileoffset,
+			       XFS_DQUOT_CLUSTER_SIZE_FSB, &map, &nmaps, 0);
+
+	xfs_iunlock(quotip, lock_mode);
+	if (error)
+		return error;
+
+	ASSERT(nmaps == 1);
+	ASSERT(map.br_blockcount == 1);
+
+	/*
+	 * Offset of dquot in the (fixed sized) dquot chunk.
+	 */
+	dqp->q_bufoffset = (id % mp->m_quotainfo->qi_dqperchunk) *
+		sizeof(xfs_dqblk_t);
+
+	ASSERT(map.br_startblock != DELAYSTARTBLOCK);
+	if (map.br_startblock == HOLESTARTBLOCK) {
+		/*
+		 * We don't allocate unless we're asked to
+		 */
+		if (!(flags & XFS_QMOPT_DQALLOC))
+			return -ENOENT;
+
+		ASSERT(tp);
+		error = xfs_qm_dqalloc(tpp, mp, dqp, quotip,
+					dqp->q_fileoffset, &bp);
+		if (error)
+			return error;
+		tp = *tpp;
+	} else {
+		trace_xfs_dqtobp_read(dqp);
+
+		/*
+		 * store the blkno etc so that we don't have to do the
+		 * mapping all the time
+		 */
+		dqp->q_blkno = XFS_FSB_TO_DADDR(mp, map.br_startblock);
+
+		error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
+					   dqp->q_blkno,
+					   mp->m_quotainfo->qi_dqchunklen,
+					   0, &bp, &xfs_dquot_buf_ops);
+
+		if (error == -EFSCORRUPTED && (flags & XFS_QMOPT_DQREPAIR)) {
+			xfs_dqid_t firstid = (xfs_dqid_t)map.br_startoff *
+						mp->m_quotainfo->qi_dqperchunk;
+			ASSERT(bp == NULL);
+			error = xfs_qm_dqrepair(mp, tp, dqp, firstid, &bp);
+		}
+
+		if (error) {
+			ASSERT(bp == NULL);
+			return error;
+		}
+	}
+
+	ASSERT(xfs_buf_islocked(bp));
+	*O_bpp = bp;
+	*O_ddpp = bp->b_addr + dqp->q_bufoffset;
+
+	return 0;
+}
+
+
+/*
+ * Read in the ondisk dquot using dqtobp() then copy it to an incore version,
+ * and release the buffer immediately.
+ *
+ * If XFS_QMOPT_DQALLOC is set, allocate a dquot on disk if it needed.
+ */
+int
+xfs_qm_dqread(
+	struct xfs_mount	*mp,
+	xfs_dqid_t		id,
+	uint			type,
+	uint			flags,
+	struct xfs_dquot	**O_dqpp)
+{
+	struct xfs_dquot	*dqp;
+	struct xfs_disk_dquot	*ddqp;
+	struct xfs_buf		*bp;
+	struct xfs_trans	*tp = NULL;
+	int			error;
+	int			cancelflags = 0;
+
+
+	dqp = kmem_zone_zalloc(xfs_qm_dqzone, KM_SLEEP);
+
+	dqp->dq_flags = type;
+	dqp->q_core.d_id = cpu_to_be32(id);
+	dqp->q_mount = mp;
+	INIT_LIST_HEAD(&dqp->q_lru);
+	mutex_init(&dqp->q_qlock);
+	init_waitqueue_head(&dqp->q_pinwait);
+
+	/*
+	 * Because we want to use a counting completion, complete
+	 * the flush completion once to allow a single access to
+	 * the flush completion without blocking.
+	 */
+	init_completion(&dqp->q_flush);
+	complete(&dqp->q_flush);
+
+	/*
+	 * Make sure group quotas have a different lock class than user
+	 * quotas.
+	 */
+	switch (type) {
+	case XFS_DQ_USER:
+		/* uses the default lock class */
+		break;
+	case XFS_DQ_GROUP:
+		lockdep_set_class(&dqp->q_qlock, &xfs_dquot_group_class);
+		break;
+	case XFS_DQ_PROJ:
+		lockdep_set_class(&dqp->q_qlock, &xfs_dquot_project_class);
+		break;
+	default:
+		ASSERT(0);
+		break;
+	}
+
+	XFS_STATS_INC(xs_qm_dquot);
+
+	trace_xfs_dqread(dqp);
+
+	if (flags & XFS_QMOPT_DQALLOC) {
+		tp = xfs_trans_alloc(mp, XFS_TRANS_QM_DQALLOC);
+		error = xfs_trans_reserve(tp, &M_RES(mp)->tr_qm_dqalloc,
+					  XFS_QM_DQALLOC_SPACE_RES(mp), 0);
+		if (error)
+			goto error1;
+		cancelflags = XFS_TRANS_RELEASE_LOG_RES;
+	}
+
+	/*
+	 * get a pointer to the on-disk dquot and the buffer containing it
+	 * dqp already knows its own type (GROUP/USER).
+	 */
+	error = xfs_qm_dqtobp(&tp, dqp, &ddqp, &bp, flags);
+	if (error) {
+		/*
+		 * This can happen if quotas got turned off (ESRCH),
+		 * or if the dquot didn't exist on disk and we ask to
+		 * allocate (ENOENT).
+		 */
+		trace_xfs_dqread_fail(dqp);
+		cancelflags |= XFS_TRANS_ABORT;
+		goto error1;
+	}
+
+	/* copy everything from disk dquot to the incore dquot */
+	memcpy(&dqp->q_core, ddqp, sizeof(xfs_disk_dquot_t));
+	xfs_qm_dquot_logitem_init(dqp);
+
+	/*
+	 * Reservation counters are defined as reservation plus current usage
+	 * to avoid having to add every time.
+	 */
+	dqp->q_res_bcount = be64_to_cpu(ddqp->d_bcount);
+	dqp->q_res_icount = be64_to_cpu(ddqp->d_icount);
+	dqp->q_res_rtbcount = be64_to_cpu(ddqp->d_rtbcount);
+
+	/* initialize the dquot speculative prealloc thresholds */
+	xfs_dquot_set_prealloc_limits(dqp);
+
+	/* Mark the buf so that this will stay incore a little longer */
+	xfs_buf_set_ref(bp, XFS_DQUOT_REF);
+
+	/*
+	 * We got the buffer with a xfs_trans_read_buf() (in dqtobp())
+	 * So we need to release with xfs_trans_brelse().
+	 * The strategy here is identical to that of inodes; we lock
+	 * the dquot in xfs_qm_dqget() before making it accessible to
+	 * others. This is because dquots, like inodes, need a good level of
+	 * concurrency, and we don't want to take locks on the entire buffers
+	 * for dquot accesses.
+	 * Note also that the dquot buffer may even be dirty at this point, if
+	 * this particular dquot was repaired. We still aren't afraid to
+	 * brelse it because we have the changes incore.
+	 */
+	ASSERT(xfs_buf_islocked(bp));
+	xfs_trans_brelse(tp, bp);
+
+	if (tp) {
+		error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
+		if (error)
+			goto error0;
+	}
+
+	*O_dqpp = dqp;
+	return error;
+
+error1:
+	if (tp)
+		xfs_trans_cancel(tp, cancelflags);
+error0:
+	xfs_qm_dqdestroy(dqp);
+	*O_dqpp = NULL;
+	return error;
+}
+
+/*
+ * Given the file system, inode OR id, and type (UDQUOT/GDQUOT), return a
+ * a locked dquot, doing an allocation (if requested) as needed.
+ * When both an inode and an id are given, the inode's id takes precedence.
+ * That is, if the id changes while we don't hold the ilock inside this
+ * function, the new dquot is returned, not necessarily the one requested
+ * in the id argument.
+ */
+int
+xfs_qm_dqget(
+	xfs_mount_t	*mp,
+	xfs_inode_t	*ip,	  /* locked inode (optional) */
+	xfs_dqid_t	id,	  /* uid/projid/gid depending on type */
+	uint		type,	  /* XFS_DQ_USER/XFS_DQ_PROJ/XFS_DQ_GROUP */
+	uint		flags,	  /* DQALLOC, DQSUSER, DQREPAIR, DOWARN */
+	xfs_dquot_t	**O_dqpp) /* OUT : locked incore dquot */
+{
+	struct xfs_quotainfo	*qi = mp->m_quotainfo;
+	struct radix_tree_root *tree = xfs_dquot_tree(qi, type);
+	struct xfs_dquot	*dqp;
+	int			error;
+
+	ASSERT(XFS_IS_QUOTA_RUNNING(mp));
+	if ((! XFS_IS_UQUOTA_ON(mp) && type == XFS_DQ_USER) ||
+	    (! XFS_IS_PQUOTA_ON(mp) && type == XFS_DQ_PROJ) ||
+	    (! XFS_IS_GQUOTA_ON(mp) && type == XFS_DQ_GROUP)) {
+		return -ESRCH;
+	}
+
+#ifdef DEBUG
+	if (xfs_do_dqerror) {
+		if ((xfs_dqerror_target == mp->m_ddev_targp) &&
+		    (xfs_dqreq_num++ % xfs_dqerror_mod) == 0) {
+			xfs_debug(mp, "Returning error in dqget");
+			return -EIO;
+		}
+	}
+
+	ASSERT(type == XFS_DQ_USER ||
+	       type == XFS_DQ_PROJ ||
+	       type == XFS_DQ_GROUP);
+	if (ip) {
+		ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+		ASSERT(xfs_inode_dquot(ip, type) == NULL);
+	}
+#endif
+
+restart:
+	mutex_lock(&qi->qi_tree_lock);
+	dqp = radix_tree_lookup(tree, id);
+	if (dqp) {
+		xfs_dqlock(dqp);
+		if (dqp->dq_flags & XFS_DQ_FREEING) {
+			xfs_dqunlock(dqp);
+			mutex_unlock(&qi->qi_tree_lock);
+			trace_xfs_dqget_freeing(dqp);
+			delay(1);
+			goto restart;
+		}
+
+		dqp->q_nrefs++;
+		mutex_unlock(&qi->qi_tree_lock);
+
+		trace_xfs_dqget_hit(dqp);
+		XFS_STATS_INC(xs_qm_dqcachehits);
+		*O_dqpp = dqp;
+		return 0;
+	}
+	mutex_unlock(&qi->qi_tree_lock);
+	XFS_STATS_INC(xs_qm_dqcachemisses);
+
+	/*
+	 * Dquot cache miss. We don't want to keep the inode lock across
+	 * a (potential) disk read. Also we don't want to deal with the lock
+	 * ordering between quotainode and this inode. OTOH, dropping the inode
+	 * lock here means dealing with a chown that can happen before
+	 * we re-acquire the lock.
+	 */
+	if (ip)
+		xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
+	error = xfs_qm_dqread(mp, id, type, flags, &dqp);
+
+	if (ip)
+		xfs_ilock(ip, XFS_ILOCK_EXCL);
+
+	if (error)
+		return error;
+
+	if (ip) {
+		/*
+		 * A dquot could be attached to this inode by now, since
+		 * we had dropped the ilock.
+		 */
+		if (xfs_this_quota_on(mp, type)) {
+			struct xfs_dquot	*dqp1;
+
+			dqp1 = xfs_inode_dquot(ip, type);
+			if (dqp1) {
+				xfs_qm_dqdestroy(dqp);
+				dqp = dqp1;
+				xfs_dqlock(dqp);
+				goto dqret;
+			}
+		} else {
+			/* inode stays locked on return */
+			xfs_qm_dqdestroy(dqp);
+			return -ESRCH;
+		}
+	}
+
+	mutex_lock(&qi->qi_tree_lock);
+	error = radix_tree_insert(tree, id, dqp);
+	if (unlikely(error)) {
+		WARN_ON(error != -EEXIST);
+
+		/*
+		 * Duplicate found. Just throw away the new dquot and start
+		 * over.
+		 */
+		mutex_unlock(&qi->qi_tree_lock);
+		trace_xfs_dqget_dup(dqp);
+		xfs_qm_dqdestroy(dqp);
+		XFS_STATS_INC(xs_qm_dquot_dups);
+		goto restart;
+	}
+
+	/*
+	 * We return a locked dquot to the caller, with a reference taken
+	 */
+	xfs_dqlock(dqp);
+	dqp->q_nrefs = 1;
+
+	qi->qi_dquots++;
+	mutex_unlock(&qi->qi_tree_lock);
+
+ dqret:
+	ASSERT((ip == NULL) || xfs_isilocked(ip, XFS_ILOCK_EXCL));
+	trace_xfs_dqget_miss(dqp);
+	*O_dqpp = dqp;
+	return 0;
+}
+
+/*
+ * Release a reference to the dquot (decrement ref-count) and unlock it.
+ *
+ * If there is a group quota attached to this dquot, carefully release that
+ * too without tripping over deadlocks'n'stuff.
+ */
+void
+xfs_qm_dqput(
+	struct xfs_dquot	*dqp)
+{
+	ASSERT(dqp->q_nrefs > 0);
+	ASSERT(XFS_DQ_IS_LOCKED(dqp));
+
+	trace_xfs_dqput(dqp);
+
+	if (--dqp->q_nrefs == 0) {
+		struct xfs_quotainfo	*qi = dqp->q_mount->m_quotainfo;
+		trace_xfs_dqput_free(dqp);
+
+		if (list_lru_add(&qi->qi_lru, &dqp->q_lru))
+			XFS_STATS_INC(xs_qm_dquot_unused);
+	}
+	xfs_dqunlock(dqp);
+}
+
+/*
+ * Release a dquot. Flush it if dirty, then dqput() it.
+ * dquot must not be locked.
+ */
+void
+xfs_qm_dqrele(
+	xfs_dquot_t	*dqp)
+{
+	if (!dqp)
+		return;
+
+	trace_xfs_dqrele(dqp);
+
+	xfs_dqlock(dqp);
+	/*
+	 * We don't care to flush it if the dquot is dirty here.
+	 * That will create stutters that we want to avoid.
+	 * Instead we do a delayed write when we try to reclaim
+	 * a dirty dquot. Also xfs_sync will take part of the burden...
+	 */
+	xfs_qm_dqput(dqp);
+}
+
+/*
+ * This is the dquot flushing I/O completion routine.  It is called
+ * from interrupt level when the buffer containing the dquot is
+ * flushed to disk.  It is responsible for removing the dquot logitem
+ * from the AIL if it has not been re-logged, and unlocking the dquot's
+ * flush lock. This behavior is very similar to that of inodes..
+ */
+STATIC void
+xfs_qm_dqflush_done(
+	struct xfs_buf		*bp,
+	struct xfs_log_item	*lip)
+{
+	xfs_dq_logitem_t	*qip = (struct xfs_dq_logitem *)lip;
+	xfs_dquot_t		*dqp = qip->qli_dquot;
+	struct xfs_ail		*ailp = lip->li_ailp;
+
+	/*
+	 * We only want to pull the item from the AIL if its
+	 * location in the log has not changed since we started the flush.
+	 * Thus, we only bother if the dquot's lsn has
+	 * not changed. First we check the lsn outside the lock
+	 * since it's cheaper, and then we recheck while
+	 * holding the lock before removing the dquot from the AIL.
+	 */
+	if ((lip->li_flags & XFS_LI_IN_AIL) &&
+	    lip->li_lsn == qip->qli_flush_lsn) {
+
+		/* xfs_trans_ail_delete() drops the AIL lock. */
+		spin_lock(&ailp->xa_lock);
+		if (lip->li_lsn == qip->qli_flush_lsn)
+			xfs_trans_ail_delete(ailp, lip, SHUTDOWN_CORRUPT_INCORE);
+		else
+			spin_unlock(&ailp->xa_lock);
+	}
+
+	/*
+	 * Release the dq's flush lock since we're done with it.
+	 */
+	xfs_dqfunlock(dqp);
+}
+
+/*
+ * Write a modified dquot to disk.
+ * The dquot must be locked and the flush lock too taken by caller.
+ * The flush lock will not be unlocked until the dquot reaches the disk,
+ * but the dquot is free to be unlocked and modified by the caller
+ * in the interim. Dquot is still locked on return. This behavior is
+ * identical to that of inodes.
+ */
+int
+xfs_qm_dqflush(
+	struct xfs_dquot	*dqp,
+	struct xfs_buf		**bpp)
+{
+	struct xfs_mount	*mp = dqp->q_mount;
+	struct xfs_buf		*bp;
+	struct xfs_disk_dquot	*ddqp;
+	int			error;
+
+	ASSERT(XFS_DQ_IS_LOCKED(dqp));
+	ASSERT(!completion_done(&dqp->q_flush));
+
+	trace_xfs_dqflush(dqp);
+
+	*bpp = NULL;
+
+	xfs_qm_dqunpin_wait(dqp);
+
+	/*
+	 * This may have been unpinned because the filesystem is shutting
+	 * down forcibly. If that's the case we must not write this dquot
+	 * to disk, because the log record didn't make it to disk.
+	 *
+	 * We also have to remove the log item from the AIL in this case,
+	 * as we wait for an emptry AIL as part of the unmount process.
+	 */
+	if (XFS_FORCED_SHUTDOWN(mp)) {
+		struct xfs_log_item	*lip = &dqp->q_logitem.qli_item;
+		dqp->dq_flags &= ~XFS_DQ_DIRTY;
+
+		spin_lock(&mp->m_ail->xa_lock);
+		if (lip->li_flags & XFS_LI_IN_AIL)
+			xfs_trans_ail_delete(mp->m_ail, lip,
+					     SHUTDOWN_CORRUPT_INCORE);
+		else
+			spin_unlock(&mp->m_ail->xa_lock);
+		error = -EIO;
+		goto out_unlock;
+	}
+
+	/*
+	 * Get the buffer containing the on-disk dquot
+	 */
+	error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp, dqp->q_blkno,
+				   mp->m_quotainfo->qi_dqchunklen, 0, &bp,
+				   &xfs_dquot_buf_ops);
+	if (error)
+		goto out_unlock;
+
+	/*
+	 * Calculate the location of the dquot inside the buffer.
+	 */
+	ddqp = bp->b_addr + dqp->q_bufoffset;
+
+	/*
+	 * A simple sanity check in case we got a corrupted dquot..
+	 */
+	error = xfs_dqcheck(mp, &dqp->q_core, be32_to_cpu(ddqp->d_id), 0,
+			   XFS_QMOPT_DOWARN, "dqflush (incore copy)");
+	if (error) {
+		xfs_buf_relse(bp);
+		xfs_dqfunlock(dqp);
+		xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
+		return -EIO;
+	}
+
+	/* This is the only portion of data that needs to persist */
+	memcpy(ddqp, &dqp->q_core, sizeof(xfs_disk_dquot_t));
+
+	/*
+	 * Clear the dirty field and remember the flush lsn for later use.
+	 */
+	dqp->dq_flags &= ~XFS_DQ_DIRTY;
+
+	xfs_trans_ail_copy_lsn(mp->m_ail, &dqp->q_logitem.qli_flush_lsn,
+					&dqp->q_logitem.qli_item.li_lsn);
+
+	/*
+	 * copy the lsn into the on-disk dquot now while we have the in memory
+	 * dquot here. This can't be done later in the write verifier as we
+	 * can't get access to the log item at that point in time.
+	 *
+	 * We also calculate the CRC here so that the on-disk dquot in the
+	 * buffer always has a valid CRC. This ensures there is no possibility
+	 * of a dquot without an up-to-date CRC getting to disk.
+	 */
+	if (xfs_sb_version_hascrc(&mp->m_sb)) {
+		struct xfs_dqblk *dqb = (struct xfs_dqblk *)ddqp;
+
+		dqb->dd_lsn = cpu_to_be64(dqp->q_logitem.qli_item.li_lsn);
+		xfs_update_cksum((char *)dqb, sizeof(struct xfs_dqblk),
+				 XFS_DQUOT_CRC_OFF);
+	}
+
+	/*
+	 * Attach an iodone routine so that we can remove this dquot from the
+	 * AIL and release the flush lock once the dquot is synced to disk.
+	 */
+	xfs_buf_attach_iodone(bp, xfs_qm_dqflush_done,
+				  &dqp->q_logitem.qli_item);
+
+	/*
+	 * If the buffer is pinned then push on the log so we won't
+	 * get stuck waiting in the write for too long.
+	 */
+	if (xfs_buf_ispinned(bp)) {
+		trace_xfs_dqflush_force(dqp);
+		xfs_log_force(mp, 0);
+	}
+
+	trace_xfs_dqflush_done(dqp);
+	*bpp = bp;
+	return 0;
+
+out_unlock:
+	xfs_dqfunlock(dqp);
+	return -EIO;
+}
+
+/*
+ * Lock two xfs_dquot structures.
+ *
+ * To avoid deadlocks we always lock the quota structure with
+ * the lowerd id first.
+ */
+void
+xfs_dqlock2(
+	xfs_dquot_t	*d1,
+	xfs_dquot_t	*d2)
+{
+	if (d1 && d2) {
+		ASSERT(d1 != d2);
+		if (be32_to_cpu(d1->q_core.d_id) >
+		    be32_to_cpu(d2->q_core.d_id)) {
+			mutex_lock(&d2->q_qlock);
+			mutex_lock_nested(&d1->q_qlock, XFS_QLOCK_NESTED);
+		} else {
+			mutex_lock(&d1->q_qlock);
+			mutex_lock_nested(&d2->q_qlock, XFS_QLOCK_NESTED);
+		}
+	} else if (d1) {
+		mutex_lock(&d1->q_qlock);
+	} else if (d2) {
+		mutex_lock(&d2->q_qlock);
+	}
+}
+
+int __init
+xfs_qm_init(void)
+{
+	xfs_qm_dqzone =
+		kmem_zone_init(sizeof(struct xfs_dquot), "xfs_dquot");
+	if (!xfs_qm_dqzone)
+		goto out;
+
+	xfs_qm_dqtrxzone =
+		kmem_zone_init(sizeof(struct xfs_dquot_acct), "xfs_dqtrx");
+	if (!xfs_qm_dqtrxzone)
+		goto out_free_dqzone;
+
+	return 0;
+
+out_free_dqzone:
+	kmem_zone_destroy(xfs_qm_dqzone);
+out:
+	return -ENOMEM;
+}
+
+void
+xfs_qm_exit(void)
+{
+	kmem_zone_destroy(xfs_qm_dqtrxzone);
+	kmem_zone_destroy(xfs_qm_dqzone);
+}