[PATCH 0/9] Log and transaction cleanups, factoring and bug fixes

[PATCH 0/9] Log and transaction cleanups, factoring and bug fixes

[Dave Chinner]

The following series is preparation for delayed logging patches. The cleanups
and factoring patches are mainly to make it simple to introduce the delayed
logging patches, especially as these changes really have nothing to do with
delayed logging. The cleanups and factoring patches should be no-ops from a
functionality point of view.

A couple of the patches are fixes for bugs that I've found as I've been working
through delayed logging prototypes.

The final two patches introduce a new log vector structure and factor
xlog_write(). This is probably the most complex of the changes - it should be a
no-op - so needs the most scrutiny. It's also one of the first changes I made -
it's been running through QA for the past month and a half so I think it is
all OK. I certainly found the factored code far easier to work with when it
came to debugging problems...

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[PATCH 1/9] xfs: factor log item initialisation

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

Each log item type does manual initialisation of the log item.
Delayed logging introduceѕ new fields that need initialisation, so
factor all the open coded initialisation into a common function
first.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/quota/xfs_dquot_item.c |   12 ++++--------
 fs/xfs/xfs_buf_item.c         |    5 +----
 fs/xfs/xfs_extfree_item.c     |   10 ++--------
 fs/xfs/xfs_inode_item.c       |   12 ++----------
 fs/xfs/xfs_log.c              |   13 +++++++++++++
 fs/xfs/xfs_log.h              |    7 +++++++
 6 files changed, 29 insertions(+), 30 deletions(-)

diff --git a/fs/xfs/quota/xfs_dquot_item.c b/fs/xfs/quota/xfs_dquot_item.c
index 4e4ee9a..639d965 100644
--- a/fs/xfs/quota/xfs_dquot_item.c
+++ b/fs/xfs/quota/xfs_dquot_item.c
@@ -357,9 +357,8 @@ xfs_qm_dquot_logitem_init(
 	xfs_dq_logitem_t  *lp;
 	lp = &dqp->q_logitem;
 
-	lp->qli_item.li_type = XFS_LI_DQUOT;
-	lp->qli_item.li_ops = &xfs_dquot_item_ops;
-	lp->qli_item.li_mountp = dqp->q_mount;
+	xfs_log_item_init(dqp->q_mount, &lp->qli_item, XFS_LI_DQUOT,
+					&xfs_dquot_item_ops);
 	lp->qli_dquot = dqp;
 	lp->qli_format.qlf_type = XFS_LI_DQUOT;
 	lp->qli_format.qlf_id = be32_to_cpu(dqp->q_core.d_id);
@@ -586,11 +585,8 @@ xfs_qm_qoff_logitem_init(
 
 	qf = (xfs_qoff_logitem_t*) kmem_zalloc(sizeof(xfs_qoff_logitem_t), KM_SLEEP);
 
-	qf->qql_item.li_type = XFS_LI_QUOTAOFF;
-	if (start)
-		qf->qql_item.li_ops = &xfs_qm_qoffend_logitem_ops;
-	else
-		qf->qql_item.li_ops = &xfs_qm_qoff_logitem_ops;
+	xfs_log_item_init(mp, &qf->qql_item, XFS_LI_QUOTAOFF, start ?
+			&xfs_qm_qoffend_logitem_ops : &xfs_qm_qoff_logitem_ops);
 	qf->qql_item.li_mountp = mp;
 	qf->qql_format.qf_type = XFS_LI_QUOTAOFF;
 	qf->qql_format.qf_flags = flags;
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index f3c49e6..aace237 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -733,10 +733,7 @@ xfs_buf_item_init(
 
 	bip = (xfs_buf_log_item_t*)kmem_zone_zalloc(xfs_buf_item_zone,
 						    KM_SLEEP);
-	bip->bli_item.li_type = XFS_LI_BUF;
-	bip->bli_item.li_ops = &xfs_buf_item_ops;
-	bip->bli_item.li_mountp = mp;
-	bip->bli_item.li_ailp = mp->m_ail;
+	xfs_log_item_init(mp, &bip->bli_item, XFS_LI_BUF, &xfs_buf_item_ops);
 	bip->bli_buf = bp;
 	xfs_buf_hold(bp);
 	bip->bli_format.blf_type = XFS_LI_BUF;
diff --git a/fs/xfs/xfs_extfree_item.c b/fs/xfs/xfs_extfree_item.c
index 6f35ed1..e461e93 100644
--- a/fs/xfs/xfs_extfree_item.c
+++ b/fs/xfs/xfs_extfree_item.c
@@ -259,10 +259,7 @@ xfs_efi_init(xfs_mount_t	*mp,
 							     KM_SLEEP);
 	}
 
-	efip->efi_item.li_type = XFS_LI_EFI;
-	efip->efi_item.li_ops = &xfs_efi_item_ops;
-	efip->efi_item.li_mountp = mp;
-	efip->efi_item.li_ailp = mp->m_ail;
+	xfs_log_item_init(mp, &efip->efi_item, XFS_LI_EFI, &xfs_efi_item_ops);
 	efip->efi_format.efi_nextents = nextents;
 	efip->efi_format.efi_id = (__psint_t)(void*)efip;
 
@@ -554,10 +551,7 @@ xfs_efd_init(xfs_mount_t	*mp,
 							     KM_SLEEP);
 	}
 
-	efdp->efd_item.li_type = XFS_LI_EFD;
-	efdp->efd_item.li_ops = &xfs_efd_item_ops;
-	efdp->efd_item.li_mountp = mp;
-	efdp->efd_item.li_ailp = mp->m_ail;
+	xfs_log_item_init(mp, &efdp->efd_item, XFS_LI_EFD, &xfs_efd_item_ops);
 	efdp->efd_efip = efip;
 	efdp->efd_format.efd_nextents = nextents;
 	efdp->efd_format.efd_efi_id = efip->efi_format.efi_id;
diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c
index 7bfea85..32e4188 100644
--- a/fs/xfs/xfs_inode_item.c
+++ b/fs/xfs/xfs_inode_item.c
@@ -865,17 +865,9 @@ xfs_inode_item_init(
 	ASSERT(ip->i_itemp == NULL);
 	iip = ip->i_itemp = kmem_zone_zalloc(xfs_ili_zone, KM_SLEEP);
 
-	iip->ili_item.li_type = XFS_LI_INODE;
-	iip->ili_item.li_ops = &xfs_inode_item_ops;
-	iip->ili_item.li_mountp = mp;
-	iip->ili_item.li_ailp = mp->m_ail;
 	iip->ili_inode = ip;
-
-	/*
-	   We have zeroed memory. No need ...
-	   iip->ili_extents_buf = NULL;
-	 */
-
+	xfs_log_item_init(mp, &iip->ili_item, XFS_LI_INODE,
+						&xfs_inode_item_ops);
 	iip->ili_format.ilf_type = XFS_LI_INODE;
 	iip->ili_format.ilf_ino = ip->i_ino;
 	iip->ili_format.ilf_blkno = ip->i_imap.im_blkno;
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index e8fba92..1f26a97 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -648,6 +648,19 @@ xfs_log_unmount(xfs_mount_t *mp)
 	xlog_dealloc_log(mp->m_log);
 }
 
+void
+xfs_log_item_init(
+	struct xfs_mount	*mp,
+	struct xfs_log_item	*item,
+	int			type,
+	struct xfs_item_ops	*ops)
+{
+	item->li_mountp = mp;
+	item->li_ailp = mp->m_ail;
+	item->li_type = type;
+	item->li_ops = ops;
+}
+
 /*
  * Write region vectors to log.  The write happens using the space reservation
  * of the ticket (tic).  It is not a requirement that all writes for a given
diff --git a/fs/xfs/xfs_log.h b/fs/xfs/xfs_log.h
index 97a24c7..f3a564d 100644
--- a/fs/xfs/xfs_log.h
+++ b/fs/xfs/xfs_log.h
@@ -126,6 +126,13 @@ typedef struct xfs_log_callback {
 struct xfs_mount;
 struct xlog_in_core;
 struct xlog_ticket;
+struct xfs_log_item;
+struct xfs_item_ops;
+
+void	xfs_log_item_init(struct xfs_mount	*mp,
+			struct xfs_log_item	*item,
+			int			type,
+			struct xfs_item_ops	*ops);
 
 xfs_lsn_t xfs_log_done(struct xfs_mount *mp,
 		       struct xlog_ticket *ticket,
-- 
1.6.5

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[PATCH 2/9] xfs: Add inode pin counts to traces

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

We don't record pin counts in inode events right now, and this makes
it difficult to track down problems related to pinning inodes. Add
the pin count to the inode trace class and add trace events for
pinning and unpinning inodes.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/linux-2.6/xfs_trace.h |    9 ++++++++-
 fs/xfs/xfs_inode.c           |    2 ++
 fs/xfs/xfs_inode_item.c      |    2 ++
 3 files changed, 12 insertions(+), 1 deletions(-)

diff --git a/fs/xfs/linux-2.6/xfs_trace.h b/fs/xfs/linux-2.6/xfs_trace.h
index fcaa62f..6537185 100644
--- a/fs/xfs/linux-2.6/xfs_trace.h
+++ b/fs/xfs/linux-2.6/xfs_trace.h
@@ -562,18 +562,21 @@ DECLARE_EVENT_CLASS(xfs_inode_class,
 		__field(dev_t, dev)
 		__field(xfs_ino_t, ino)
 		__field(int, count)
+		__field(int, pincount)
 		__field(unsigned long, caller_ip)
 	),
 	TP_fast_assign(
 		__entry->dev = VFS_I(ip)->i_sb->s_dev;
 		__entry->ino = ip->i_ino;
 		__entry->count = atomic_read(&VFS_I(ip)->i_count);
+		__entry->pincount = atomic_read(&ip->i_pincount);
 		__entry->caller_ip = caller_ip;
 	),
-	TP_printk("dev %d:%d ino 0x%llx count %d caller %pf",
+	TP_printk("dev %d:%d ino 0x%llx count %d pincount %d caller %pf",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  __entry->ino,
 		  __entry->count,
+		  __entry->pincount,
 		  (char *)__entry->caller_ip)
 )
 
@@ -583,6 +586,10 @@ DEFINE_EVENT(xfs_inode_class, name, \
 	TP_ARGS(ip, caller_ip))
 DEFINE_INODE_EVENT(xfs_ihold);
 DEFINE_INODE_EVENT(xfs_irele);
+DEFINE_INODE_EVENT(xfs_inode_pin);
+DEFINE_INODE_EVENT(xfs_inode_unpin);
+DEFINE_INODE_EVENT(xfs_inode_unpin_nowait);
+
 /* the old xfs_itrace_entry tracer - to be replaced by s.th. in the VFS */
 DEFINE_INODE_EVENT(xfs_inode);
 #define xfs_itrace_entry(ip)    \
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 0ffd564..8cd6e8d 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2449,6 +2449,8 @@ xfs_iunpin_nowait(
 {
 	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
 
+	trace_xfs_inode_unpin_nowait(ip, _RET_IP_);
+
 	/* Give the log a push to start the unpinning I/O */
 	xfs_log_force_lsn(ip->i_mount, ip->i_itemp->ili_last_lsn, 0);
 
diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c
index 32e4188..0347175 100644
--- a/fs/xfs/xfs_inode_item.c
+++ b/fs/xfs/xfs_inode_item.c
@@ -543,6 +543,7 @@ xfs_inode_item_pin(
 {
 	ASSERT(xfs_isilocked(iip->ili_inode, XFS_ILOCK_EXCL));
 
+	trace_xfs_inode_pin(iip->ili_inode, _RET_IP_);
 	atomic_inc(&iip->ili_inode->i_pincount);
 }
 
@@ -561,6 +562,7 @@ xfs_inode_item_unpin(
 {
 	struct xfs_inode	*ip = iip->ili_inode;
 
+	trace_xfs_inode_unpin(ip, _RET_IP_);
 	ASSERT(atomic_read(&ip->i_pincount) > 0);
 	if (atomic_dec_and_test(&ip->i_pincount))
 		wake_up(&ip->i_ipin_wait);
-- 
1.6.5

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[PATCH 3/9] xfs: remove stale parameter from ->iop_unpin method

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

The staleness of a object being unpinned can be directly derived
from the object itself - there is no need to extract it from the
object then pass it as a parameter into IOP_UNPIN().

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/quota/xfs_dquot_item.c |   16 +++++--------
 fs/xfs/xfs_buf_item.c         |   50 ++++++++++++++++++-----------------------
 fs/xfs/xfs_extfree_item.c     |    8 +++---
 fs/xfs/xfs_inode_item.c       |    7 ++---
 fs/xfs/xfs_trans.c            |    2 +-
 fs/xfs/xfs_trans.h            |    5 +--
 fs/xfs/xfs_trans_buf.c        |    3 +-
 7 files changed, 39 insertions(+), 52 deletions(-)

diff --git a/fs/xfs/quota/xfs_dquot_item.c b/fs/xfs/quota/xfs_dquot_item.c
index 639d965..165bbdf 100644
--- a/fs/xfs/quota/xfs_dquot_item.c
+++ b/fs/xfs/quota/xfs_dquot_item.c
@@ -107,8 +107,7 @@ xfs_qm_dquot_logitem_pin(
 /* ARGSUSED */
 STATIC void
 xfs_qm_dquot_logitem_unpin(
-	xfs_dq_logitem_t *logitem,
-	int		  stale)
+	xfs_dq_logitem_t *logitem)
 {
 	xfs_dquot_t *dqp = logitem->qli_dquot;
 
@@ -123,7 +122,7 @@ xfs_qm_dquot_logitem_unpin_remove(
 	xfs_dq_logitem_t *logitem,
 	xfs_trans_t	 *tp)
 {
-	xfs_qm_dquot_logitem_unpin(logitem, 0);
+	xfs_qm_dquot_logitem_unpin(logitem);
 }
 
 /*
@@ -329,8 +328,7 @@ static struct xfs_item_ops xfs_dquot_item_ops = {
 	.iop_format	= (void(*)(xfs_log_item_t*, xfs_log_iovec_t*))
 					xfs_qm_dquot_logitem_format,
 	.iop_pin	= (void(*)(xfs_log_item_t*))xfs_qm_dquot_logitem_pin,
-	.iop_unpin	= (void(*)(xfs_log_item_t*, int))
-					xfs_qm_dquot_logitem_unpin,
+	.iop_unpin	= (void(*)(xfs_log_item_t*))xfs_qm_dquot_logitem_unpin,
 	.iop_unpin_remove = (void(*)(xfs_log_item_t*, xfs_trans_t*))
 					xfs_qm_dquot_logitem_unpin_remove,
 	.iop_trylock	= (uint(*)(xfs_log_item_t*))
@@ -425,7 +423,7 @@ xfs_qm_qoff_logitem_pin(xfs_qoff_logitem_t *qf)
  */
 /*ARGSUSED*/
 STATIC void
-xfs_qm_qoff_logitem_unpin(xfs_qoff_logitem_t *qf, int stale)
+xfs_qm_qoff_logitem_unpin(xfs_qoff_logitem_t *qf)
 {
 	return;
 }
@@ -536,8 +534,7 @@ static struct xfs_item_ops xfs_qm_qoffend_logitem_ops = {
 	.iop_format	= (void(*)(xfs_log_item_t*, xfs_log_iovec_t*))
 					xfs_qm_qoff_logitem_format,
 	.iop_pin	= (void(*)(xfs_log_item_t*))xfs_qm_qoff_logitem_pin,
-	.iop_unpin	= (void(*)(xfs_log_item_t* ,int))
-					xfs_qm_qoff_logitem_unpin,
+	.iop_unpin	= (void(*)(xfs_log_item_t*))xfs_qm_qoff_logitem_unpin,
 	.iop_unpin_remove = (void(*)(xfs_log_item_t*,xfs_trans_t*))
 					xfs_qm_qoff_logitem_unpin_remove,
 	.iop_trylock	= (uint(*)(xfs_log_item_t*))xfs_qm_qoff_logitem_trylock,
@@ -558,8 +555,7 @@ static struct xfs_item_ops xfs_qm_qoff_logitem_ops = {
 	.iop_format	= (void(*)(xfs_log_item_t*, xfs_log_iovec_t*))
 					xfs_qm_qoff_logitem_format,
 	.iop_pin	= (void(*)(xfs_log_item_t*))xfs_qm_qoff_logitem_pin,
-	.iop_unpin	= (void(*)(xfs_log_item_t*, int))
-					xfs_qm_qoff_logitem_unpin,
+	.iop_unpin	= (void(*)(xfs_log_item_t*))xfs_qm_qoff_logitem_unpin,
 	.iop_unpin_remove = (void(*)(xfs_log_item_t*,xfs_trans_t*))
 					xfs_qm_qoff_logitem_unpin_remove,
 	.iop_trylock	= (uint(*)(xfs_log_item_t*))xfs_qm_qoff_logitem_trylock,
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index aace237..240340a 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -372,12 +372,12 @@ xfs_buf_item_pin(
  */
 STATIC void
 xfs_buf_item_unpin(
-	xfs_buf_log_item_t	*bip,
-	int			stale)
+	xfs_buf_log_item_t	*bip)
 {
 	struct xfs_ail	*ailp;
 	xfs_buf_t	*bp;
 	int		freed;
+	int		stale = bip->bli_flags & XFS_BLI_STALE;
 
 	bp = bip->bli_buf;
 	ASSERT(bp != NULL);
@@ -428,40 +428,34 @@ xfs_buf_item_unpin_remove(
 	xfs_buf_log_item_t	*bip,
 	xfs_trans_t		*tp)
 {
-	xfs_buf_t		*bp;
-	xfs_log_item_desc_t	*lidp;
-	int			stale = 0;
-
-	bp = bip->bli_buf;
-	/*
-	 * will xfs_buf_item_unpin() call xfs_buf_item_relse()?
-	 */
+	/* will xfs_buf_item_unpin() call xfs_buf_item_relse()? */
 	if ((atomic_read(&bip->bli_refcount) == 1) &&
 	    (bip->bli_flags & XFS_BLI_STALE)) {
+		/*
+		 * yes -- We can safely do some work here and then call
+		 * buf_item_unpin to do the rest because we are
+		 * are holding the buffer locked so no one else will be
+		 * able to bump up the refcount. We have to remove the
+		 * log item from the transaction as we are about to release
+		 * our reference to the buffer. If we don't, the unlock that
+		 * occurs later in the xfs_trans_uncommit() will try to
+		 * reference the buffer which we no longer have a hold on.
+		 */
+		struct xfs_log_item_desc *lidp;
+
 		ASSERT(XFS_BUF_VALUSEMA(bip->bli_buf) <= 0);
 		trace_xfs_buf_item_unpin_stale(bip);
 
-		/*
-		 * yes -- clear the xaction descriptor in-use flag
-		 * and free the chunk if required.  We can safely
-		 * do some work here and then call buf_item_unpin
-		 * to do the rest because if the if is true, then
-		 * we are holding the buffer locked so no one else
-		 * will be able to bump up the refcount.
-		 */
-		lidp = xfs_trans_find_item(tp, (xfs_log_item_t *) bip);
-		stale = lidp->lid_flags & XFS_LID_BUF_STALE;
+		lidp = xfs_trans_find_item(tp, (xfs_log_item_t *)bip);
 		xfs_trans_free_item(tp, lidp);
+
 		/*
-		 * Since the transaction no longer refers to the buffer,
-		 * the buffer should no longer refer to the transaction.
+		 * Since the transaction no longer refers to the buffer, the
+		 * buffer should no longer refer to the transaction.
 		 */
-		XFS_BUF_SET_FSPRIVATE2(bp, NULL);
+		XFS_BUF_SET_FSPRIVATE2(bip->bli_buf, NULL);
 	}
-
-	xfs_buf_item_unpin(bip, stale);
-
-	return;
+	xfs_buf_item_unpin(bip);
 }
 
 /*
@@ -675,7 +669,7 @@ static struct xfs_item_ops xfs_buf_item_ops = {
 	.iop_format	= (void(*)(xfs_log_item_t*, xfs_log_iovec_t*))
 					xfs_buf_item_format,
 	.iop_pin	= (void(*)(xfs_log_item_t*))xfs_buf_item_pin,
-	.iop_unpin	= (void(*)(xfs_log_item_t*, int))xfs_buf_item_unpin,
+	.iop_unpin	= (void(*)(xfs_log_item_t*))xfs_buf_item_unpin,
 	.iop_unpin_remove = (void(*)(xfs_log_item_t*, xfs_trans_t *))
 					xfs_buf_item_unpin_remove,
 	.iop_trylock	= (uint(*)(xfs_log_item_t*))xfs_buf_item_trylock,
diff --git a/fs/xfs/xfs_extfree_item.c b/fs/xfs/xfs_extfree_item.c
index e461e93..409fe81 100644
--- a/fs/xfs/xfs_extfree_item.c
+++ b/fs/xfs/xfs_extfree_item.c
@@ -106,7 +106,7 @@ xfs_efi_item_pin(xfs_efi_log_item_t *efip)
  */
 /*ARGSUSED*/
 STATIC void
-xfs_efi_item_unpin(xfs_efi_log_item_t *efip, int stale)
+xfs_efi_item_unpin(xfs_efi_log_item_t *efip)
 {
 	struct xfs_ail		*ailp = efip->efi_item.li_ailp;
 
@@ -224,7 +224,7 @@ static struct xfs_item_ops xfs_efi_item_ops = {
 	.iop_format	= (void(*)(xfs_log_item_t*, xfs_log_iovec_t*))
 					xfs_efi_item_format,
 	.iop_pin	= (void(*)(xfs_log_item_t*))xfs_efi_item_pin,
-	.iop_unpin	= (void(*)(xfs_log_item_t*, int))xfs_efi_item_unpin,
+	.iop_unpin	= (void(*)(xfs_log_item_t*))xfs_efi_item_unpin,
 	.iop_unpin_remove = (void(*)(xfs_log_item_t*, xfs_trans_t *))
 					xfs_efi_item_unpin_remove,
 	.iop_trylock	= (uint(*)(xfs_log_item_t*))xfs_efi_item_trylock,
@@ -425,7 +425,7 @@ xfs_efd_item_pin(xfs_efd_log_item_t *efdp)
  */
 /*ARGSUSED*/
 STATIC void
-xfs_efd_item_unpin(xfs_efd_log_item_t *efdp, int stale)
+xfs_efd_item_unpin(xfs_efd_log_item_t *efdp)
 {
 	return;
 }
@@ -515,7 +515,7 @@ static struct xfs_item_ops xfs_efd_item_ops = {
 	.iop_format	= (void(*)(xfs_log_item_t*, xfs_log_iovec_t*))
 					xfs_efd_item_format,
 	.iop_pin	= (void(*)(xfs_log_item_t*))xfs_efd_item_pin,
-	.iop_unpin	= (void(*)(xfs_log_item_t*, int))xfs_efd_item_unpin,
+	.iop_unpin	= (void(*)(xfs_log_item_t*))xfs_efd_item_unpin,
 	.iop_unpin_remove = (void(*)(xfs_log_item_t*, xfs_trans_t*))
 					xfs_efd_item_unpin_remove,
 	.iop_trylock	= (uint(*)(xfs_log_item_t*))xfs_efd_item_trylock,
diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c
index 0347175..cf8249a 100644
--- a/fs/xfs/xfs_inode_item.c
+++ b/fs/xfs/xfs_inode_item.c
@@ -557,8 +557,7 @@ xfs_inode_item_pin(
 /* ARGSUSED */
 STATIC void
 xfs_inode_item_unpin(
-	xfs_inode_log_item_t	*iip,
-	int			stale)
+	xfs_inode_log_item_t	*iip)
 {
 	struct xfs_inode	*ip = iip->ili_inode;
 
@@ -574,7 +573,7 @@ xfs_inode_item_unpin_remove(
 	xfs_inode_log_item_t	*iip,
 	xfs_trans_t		*tp)
 {
-	xfs_inode_item_unpin(iip, 0);
+	xfs_inode_item_unpin(iip);
 }
 
 /*
@@ -840,7 +839,7 @@ static struct xfs_item_ops xfs_inode_item_ops = {
 	.iop_format	= (void(*)(xfs_log_item_t*, xfs_log_iovec_t*))
 					xfs_inode_item_format,
 	.iop_pin	= (void(*)(xfs_log_item_t*))xfs_inode_item_pin,
-	.iop_unpin	= (void(*)(xfs_log_item_t*, int))xfs_inode_item_unpin,
+	.iop_unpin	= (void(*)(xfs_log_item_t*))xfs_inode_item_unpin,
 	.iop_unpin_remove = (void(*)(xfs_log_item_t*, xfs_trans_t*))
 					xfs_inode_item_unpin_remove,
 	.iop_trylock	= (uint(*)(xfs_log_item_t*))xfs_inode_item_trylock,
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index f73e358..6962f2b 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -1451,6 +1451,6 @@ xfs_trans_chunk_committed(
 		 * flags, if anyone else stales the buffer we do not
 		 * want to pay any attention to it.
 		 */
-		IOP_UNPIN(lip, lidp->lid_flags & XFS_LID_BUF_STALE);
+		IOP_UNPIN(lip);
 	}
 }
diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h
index 79c8bab..82574ef 100644
--- a/fs/xfs/xfs_trans.h
+++ b/fs/xfs/xfs_trans.h
@@ -159,7 +159,6 @@ typedef struct xfs_log_item_desc {
 
 #define XFS_LID_DIRTY		0x1
 #define XFS_LID_PINNED		0x2
-#define XFS_LID_BUF_STALE	0x8
 
 /*
  * This structure is used to maintain a chunk list of log_item_desc
@@ -833,7 +832,7 @@ typedef struct xfs_item_ops {
 	uint (*iop_size)(xfs_log_item_t *);
 	void (*iop_format)(xfs_log_item_t *, struct xfs_log_iovec *);
 	void (*iop_pin)(xfs_log_item_t *);
-	void (*iop_unpin)(xfs_log_item_t *, int);
+	void (*iop_unpin)(xfs_log_item_t *);
 	void (*iop_unpin_remove)(xfs_log_item_t *, struct xfs_trans *);
 	uint (*iop_trylock)(xfs_log_item_t *);
 	void (*iop_unlock)(xfs_log_item_t *);
@@ -846,7 +845,7 @@ typedef struct xfs_item_ops {
 #define IOP_SIZE(ip)		(*(ip)->li_ops->iop_size)(ip)
 #define IOP_FORMAT(ip,vp)	(*(ip)->li_ops->iop_format)(ip, vp)
 #define IOP_PIN(ip)		(*(ip)->li_ops->iop_pin)(ip)
-#define IOP_UNPIN(ip, flags)	(*(ip)->li_ops->iop_unpin)(ip, flags)
+#define IOP_UNPIN(ip)		(*(ip)->li_ops->iop_unpin)(ip)
 #define IOP_UNPIN_REMOVE(ip,tp) (*(ip)->li_ops->iop_unpin_remove)(ip, tp)
 #define IOP_TRYLOCK(ip)		(*(ip)->li_ops->iop_trylock)(ip)
 #define IOP_UNLOCK(ip)		(*(ip)->li_ops->iop_unlock)(ip)
diff --git a/fs/xfs/xfs_trans_buf.c b/fs/xfs/xfs_trans_buf.c
index fb58636..4e1b689 100644
--- a/fs/xfs/xfs_trans_buf.c
+++ b/fs/xfs/xfs_trans_buf.c
@@ -696,7 +696,6 @@ xfs_trans_log_buf(xfs_trans_t	*tp,
 
 	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);
 }
@@ -782,7 +781,7 @@ xfs_trans_binval(
 	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;
+	lidp->lid_flags |= XFS_LID_DIRTY;
 	tp->t_flags |= XFS_TRANS_DIRTY;
 }
 
-- 
1.6.5

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[PATCH 4/9] xfs: fix reservation release commit flag in xfs_bmap_add_attrfork()

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

xfs_bmap_add_attrfork() passes XFS_TRANS_PERM_LOG_RES to xfs_trans_commit()
to indicate that the commit should release the permanent log reservation
as part of the commit. This is wrong - the correct flag is
XFS_TRANS_RELEASE_LOG_RES - and it is only by the chance that both these
flags have the value of 0x4 that the code is doing the right thing.

Fix it by changing to use the correct flag.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_bmap.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
index 95a4813..528a3b4 100644
--- a/fs/xfs/xfs_bmap.c
+++ b/fs/xfs/xfs_bmap.c
@@ -3834,7 +3834,7 @@ xfs_bmap_add_attrfork(
 	}
 	if ((error = xfs_bmap_finish(&tp, &flist, &committed)))
 		goto error2;
-	error = xfs_trans_commit(tp, XFS_TRANS_PERM_LOG_RES);
+	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
 	ASSERT(ip->i_df.if_ext_max ==
 	       XFS_IFORK_DSIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t));
 	return error;
-- 
1.6.5

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[PATCH 5/9] xfs: split out iclog writing from xfs_trans_commit()

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

Split the the part of xfs_trans_commit() that deals with writing the
transaction into the iclog into a separate function. This isolates the
physical commit process from the logical commit operation and makes
it easier to insert different transaction commit paths without affecting
the existing algorithm adversely.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_trans.c |  389 +++++++++++++++++++++++++++-------------------------
 1 files changed, 200 insertions(+), 189 deletions(-)

diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index 6962f2b..ac9af40 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -47,8 +47,6 @@
 
 
 STATIC void	xfs_trans_apply_sb_deltas(xfs_trans_t *);
-STATIC uint	xfs_trans_count_vecs(xfs_trans_t *);
-STATIC void	xfs_trans_fill_vecs(xfs_trans_t *, xfs_log_iovec_t *);
 STATIC void	xfs_trans_uncommit(xfs_trans_t *, uint);
 STATIC void	xfs_trans_committed(xfs_trans_t *, int);
 STATIC void	xfs_trans_chunk_committed(xfs_log_item_chunk_t *, xfs_lsn_t, int);
@@ -764,94 +762,126 @@ xfs_trans_unreserve_and_mod_sb(
 	}
 }
 
-
 /*
- * xfs_trans_commit
- *
- * Commit the given transaction to the log a/synchronously.
- *
- * XFS disk error handling mechanism is not based on a typical
- * transaction abort mechanism. Logically after the filesystem
- * gets marked 'SHUTDOWN', we can't let any new transactions
- * be durable - ie. committed to disk - because some metadata might
- * be inconsistent. In such cases, this returns an error, and the
- * caller may assume that all locked objects joined to the transaction
- * have already been unlocked as if the commit had succeeded.
- * Do not reference the transaction structure after this call.
+ * Total up the number of log iovecs needed to commit this
+ * transaction.  The transaction itself needs one for the
+ * transaction header.  Ask each dirty item in turn how many
+ * it needs to get the total.
  */
- /*ARGSUSED*/
-int
-_xfs_trans_commit(
-	xfs_trans_t	*tp,
-	uint		flags,
-	int		*log_flushed)
+static uint
+xfs_trans_count_vecs(
+	xfs_trans_t	*tp)
 {
-	xfs_log_iovec_t		*log_vector;
-	int			nvec;
-	xfs_mount_t		*mp;
-	xfs_lsn_t		commit_lsn;
-	/* REFERENCED */
-	int			error;
-	int			log_flags;
-	int			sync;
-#define	XFS_TRANS_LOGVEC_COUNT	16
-	xfs_log_iovec_t		log_vector_fast[XFS_TRANS_LOGVEC_COUNT];
-	struct xlog_in_core	*commit_iclog;
-	int			shutdown;
+	int			nvecs;
+	xfs_log_item_desc_t	*lidp;
 
-	commit_lsn = -1;
+	nvecs = 1;
+	lidp = xfs_trans_first_item(tp);
+	ASSERT(lidp != NULL);
 
-	/*
-	 * Determine whether this commit is releasing a permanent
-	 * log reservation or not.
+	/* In the non-debug case we need to start bailing out if we
+	 * didn't find a log_item here, return zero and let trans_commit
+	 * deal with it.
 	 */
-	if (flags & XFS_TRANS_RELEASE_LOG_RES) {
-		ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
-		log_flags = XFS_LOG_REL_PERM_RESERV;
-	} else {
-		log_flags = 0;
+	if (lidp == NULL)
+		return 0;
+
+	while (lidp != NULL) {
+		/*
+		 * Skip items which aren't dirty in this transaction.
+		 */
+		if (!(lidp->lid_flags & XFS_LID_DIRTY)) {
+			lidp = xfs_trans_next_item(tp, lidp);
+			continue;
+		}
+		lidp->lid_size = IOP_SIZE(lidp->lid_item);
+		nvecs += lidp->lid_size;
+		lidp = xfs_trans_next_item(tp, lidp);
 	}
-	mp = tp->t_mountp;
+
+	return nvecs;
+}
+
+/*
+ * Fill in the vector with pointers to data to be logged
+ * by this transaction.  The transaction header takes
+ * the first vector, and then each dirty item takes the
+ * number of vectors it indicated it needed in xfs_trans_count_vecs().
+ *
+ * As each item fills in the entries it needs, also pin the item
+ * so that it cannot be flushed out until the log write completes.
+ */
+static void
+xfs_trans_fill_vecs(
+	struct xfs_trans	*tp,
+	struct xfs_log_iovec	*log_vector)
+{
+	xfs_log_item_desc_t	*lidp;
+	struct xfs_log_iovec	*vecp;
+	uint			nitems;
 
 	/*
-	 * If there is nothing to be logged by the transaction,
-	 * then unlock all of the items associated with the
-	 * transaction and free the transaction structure.
-	 * Also make sure to return any reserved blocks to
-	 * the free pool.
+	 * Skip over the entry for the transaction header, we'll
+	 * fill that in at the end.
 	 */
-shut_us_down:
-	shutdown = XFS_FORCED_SHUTDOWN(mp) ? EIO : 0;
-	if (!(tp->t_flags & XFS_TRANS_DIRTY) || shutdown) {
-		xfs_trans_unreserve_and_mod_sb(tp);
+	vecp = log_vector + 1;
+
+	nitems = 0;
+	lidp = xfs_trans_first_item(tp);
+	ASSERT(lidp);
+	while (lidp) {
+		/* Skip items which aren't dirty in this transaction. */
+		if (!(lidp->lid_flags & XFS_LID_DIRTY)) {
+			lidp = xfs_trans_next_item(tp, lidp);
+			continue;
+		}
+
 		/*
-		 * It is indeed possible for the transaction to be
-		 * not dirty but the dqinfo portion to be. All that
-		 * means is that we have some (non-persistent) quota
-		 * reservations that need to be unreserved.
+		 * The item may be marked dirty but not log anything.  This can
+		 * be used to get called when a transaction is committed.
 		 */
-		xfs_trans_unreserve_and_mod_dquots(tp);
-		if (tp->t_ticket) {
-			commit_lsn = xfs_log_done(mp, tp->t_ticket,
-							NULL, log_flags);
-			if (commit_lsn == -1 && !shutdown)
-				shutdown = XFS_ERROR(EIO);
-		}
-		current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
-		xfs_trans_free_items(tp, shutdown? XFS_TRANS_ABORT : 0);
-		xfs_trans_free_busy(tp);
-		xfs_trans_free(tp);
-		XFS_STATS_INC(xs_trans_empty);
-		return (shutdown);
+		if (lidp->lid_size)
+			nitems++;
+		IOP_FORMAT(lidp->lid_item, vecp);
+		vecp += lidp->lid_size;
+		IOP_PIN(lidp->lid_item);
+		lidp = xfs_trans_next_item(tp, lidp);
 	}
-	ASSERT(tp->t_ticket != NULL);
 
 	/*
-	 * If we need to update the superblock, then do it now.
+	 * Now that we've counted the number of items in this transaction, fill
+	 * in the transaction header. Note that the transaction header does not
+	 * have a log item.
 	 */
-	if (tp->t_flags & XFS_TRANS_SB_DIRTY)
-		xfs_trans_apply_sb_deltas(tp);
-	xfs_trans_apply_dquot_deltas(tp);
+	tp->t_header.th_magic = XFS_TRANS_HEADER_MAGIC;
+	tp->t_header.th_type = tp->t_type;
+	tp->t_header.th_num_items = nitems;
+	log_vector->i_addr = (xfs_caddr_t)&tp->t_header;
+	log_vector->i_len = sizeof(xfs_trans_header_t);
+	log_vector->i_type = XLOG_REG_TYPE_TRANSHDR;
+}
+
+/*
+ * Format the transaction direct to the iclog. This isolates the physical
+ * transaction commit operation from the logical operation and hence allows
+ * other methods to be introduced without affecting the existing commit path.
+ */
+static int
+xfs_trans_commit_iclog(
+	struct xfs_mount	*mp,
+	struct xfs_trans	*tp,
+	xfs_lsn_t		*commit_lsn,
+	int			flags)
+{
+	int			shutdown;
+	int			error;
+	int			log_flags = 0;
+	struct xlog_in_core	*commit_iclog;
+#define XFS_TRANS_LOGVEC_COUNT  16
+	struct xfs_log_iovec	log_vector_fast[XFS_TRANS_LOGVEC_COUNT];
+	struct xfs_log_iovec	*log_vector;
+	uint			nvec;
+
 
 	/*
 	 * Ask each log item how many log_vector entries it will
@@ -861,8 +891,7 @@ shut_us_down:
 	 */
 	nvec = xfs_trans_count_vecs(tp);
 	if (nvec == 0) {
-		xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
-		goto shut_us_down;
+		return ENOMEM;	/* triggers a shutdown! */
 	} else if (nvec <= XFS_TRANS_LOGVEC_COUNT) {
 		log_vector = log_vector_fast;
 	} else {
@@ -877,6 +906,9 @@ shut_us_down:
 	 */
 	xfs_trans_fill_vecs(tp, log_vector);
 
+	if (flags & XFS_TRANS_RELEASE_LOG_RES)
+		log_flags = XFS_LOG_REL_PERM_RESERV;
+
 	error = xfs_log_write(mp, log_vector, nvec, tp->t_ticket, &(tp->t_lsn));
 
 	/*
@@ -884,18 +916,17 @@ shut_us_down:
 	 * at any time after this call.  However, all the items associated
 	 * with the transaction are still locked and pinned in memory.
 	 */
-	commit_lsn = xfs_log_done(mp, tp->t_ticket, &commit_iclog, log_flags);
+	*commit_lsn = xfs_log_done(mp, tp->t_ticket, &commit_iclog, log_flags);
 
-	tp->t_commit_lsn = commit_lsn;
-	if (nvec > XFS_TRANS_LOGVEC_COUNT) {
-		kmem_free(log_vector);
-	}
+	tp->t_commit_lsn = *commit_lsn;
+        if (nvec > XFS_TRANS_LOGVEC_COUNT)
+                kmem_free(log_vector);
 
 	/*
 	 * If we got a log write error. Unpin the logitems that we
 	 * had pinned, clean up, free trans structure, and return error.
 	 */
-	if (error || commit_lsn == -1) {
+	if (error || *commit_lsn == -1) {
 		current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
 		xfs_trans_uncommit(tp, flags|XFS_TRANS_ABORT);
 		return XFS_ERROR(EIO);
@@ -909,8 +940,6 @@ shut_us_down:
 	 */
 	xfs_trans_unreserve_and_mod_sb(tp);
 
-	sync = tp->t_flags & XFS_TRANS_SYNC;
-
 	/*
 	 * Tell the LM to call the transaction completion routine
 	 * when the log write with LSN commit_lsn completes (e.g.
@@ -953,7 +982,7 @@ shut_us_down:
 	 * the commit lsn of this transaction for dependency tracking
 	 * purposes.
 	 */
-	xfs_trans_unlock_items(tp, commit_lsn);
+	xfs_trans_unlock_items(tp, *commit_lsn);
 
 	/*
 	 * If we detected a log error earlier, finish committing
@@ -973,7 +1002,92 @@ shut_us_down:
 	 * and the items are released we can finally allow the iclog to
 	 * go to disk.
 	 */
-	error = xfs_log_release_iclog(mp, commit_iclog);
+	return xfs_log_release_iclog(mp, commit_iclog);
+}
+
+
+/*
+ * xfs_trans_commit
+ *
+ * Commit the given transaction to the log a/synchronously.
+ *
+ * XFS disk error handling mechanism is not based on a typical
+ * transaction abort mechanism. Logically after the filesystem
+ * gets marked 'SHUTDOWN', we can't let any new transactions
+ * be durable - ie. committed to disk - because some metadata might
+ * be inconsistent. In such cases, this returns an error, and the
+ * caller may assume that all locked objects joined to the transaction
+ * have already been unlocked as if the commit had succeeded.
+ * Do not reference the transaction structure after this call.
+ */
+ /*ARGSUSED*/
+int
+_xfs_trans_commit(
+	xfs_trans_t	*tp,
+	uint		flags,
+	int		*log_flushed)
+{
+	xfs_mount_t		*mp = tp->t_mountp;
+	xfs_lsn_t		commit_lsn = -1;
+	int			error;
+	int			log_flags = 0;
+	int			sync = tp->t_flags & XFS_TRANS_SYNC;
+	int			shutdown;
+
+	/*
+	 * Determine whether this commit is releasing a permanent
+	 * log reservation or not.
+	 */
+	if (flags & XFS_TRANS_RELEASE_LOG_RES) {
+		ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
+		log_flags = XFS_LOG_REL_PERM_RESERV;
+	}
+
+	/*
+	 * If there is nothing to be logged by the transaction,
+	 * then unlock all of the items associated with the
+	 * transaction and free the transaction structure.
+	 * Also make sure to return any reserved blocks to
+	 * the free pool.
+	 */
+shut_us_down:
+	shutdown = XFS_FORCED_SHUTDOWN(mp) ? EIO : 0;
+	if (!(tp->t_flags & XFS_TRANS_DIRTY) || shutdown) {
+		xfs_trans_unreserve_and_mod_sb(tp);
+		/*
+		 * It is indeed possible for the transaction to be
+		 * not dirty but the dqinfo portion to be. All that
+		 * means is that we have some (non-persistent) quota
+		 * reservations that need to be unreserved.
+		 */
+		xfs_trans_unreserve_and_mod_dquots(tp);
+		if (tp->t_ticket) {
+			commit_lsn = xfs_log_done(mp, tp->t_ticket,
+							NULL, log_flags);
+			if (commit_lsn == -1 && !shutdown)
+				shutdown = XFS_ERROR(EIO);
+		}
+		current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
+		xfs_trans_free_items(tp, shutdown? XFS_TRANS_ABORT : 0);
+		xfs_trans_free_busy(tp);
+		xfs_trans_free(tp);
+		XFS_STATS_INC(xs_trans_empty);
+		return (shutdown);
+	}
+	ASSERT(tp->t_ticket != NULL);
+
+	/*
+	 * If we need to update the superblock, then do it now.
+	 */
+	if (tp->t_flags & XFS_TRANS_SB_DIRTY)
+		xfs_trans_apply_sb_deltas(tp);
+	xfs_trans_apply_dquot_deltas(tp);
+
+	error = xfs_trans_commit_iclog(mp, tp, &commit_lsn, flags);
+	if (error == ENOMEM) {
+		xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
+		goto shut_us_down;
+	}
 
 	/*
 	 * If the transaction needs to be synchronous, then force the
@@ -992,47 +1106,6 @@ shut_us_down:
 	return (error);
 }
 
-
-/*
- * Total up the number of log iovecs needed to commit this
- * transaction.  The transaction itself needs one for the
- * transaction header.  Ask each dirty item in turn how many
- * it needs to get the total.
- */
-STATIC uint
-xfs_trans_count_vecs(
-	xfs_trans_t	*tp)
-{
-	int			nvecs;
-	xfs_log_item_desc_t	*lidp;
-
-	nvecs = 1;
-	lidp = xfs_trans_first_item(tp);
-	ASSERT(lidp != NULL);
-
-	/* In the non-debug case we need to start bailing out if we
-	 * didn't find a log_item here, return zero and let trans_commit
-	 * deal with it.
-	 */
-	if (lidp == NULL)
-		return 0;
-
-	while (lidp != NULL) {
-		/*
-		 * Skip items which aren't dirty in this transaction.
-		 */
-		if (!(lidp->lid_flags & XFS_LID_DIRTY)) {
-			lidp = xfs_trans_next_item(tp, lidp);
-			continue;
-		}
-		lidp->lid_size = IOP_SIZE(lidp->lid_item);
-		nvecs += lidp->lid_size;
-		lidp = xfs_trans_next_item(tp, lidp);
-	}
-
-	return nvecs;
-}
-
 /*
  * Called from the trans_commit code when we notice that
  * the filesystem is in the middle of a forced shutdown.
@@ -1063,68 +1136,6 @@ xfs_trans_uncommit(
 }
 
 /*
- * Fill in the vector with pointers to data to be logged
- * by this transaction.  The transaction header takes
- * the first vector, and then each dirty item takes the
- * number of vectors it indicated it needed in xfs_trans_count_vecs().
- *
- * As each item fills in the entries it needs, also pin the item
- * so that it cannot be flushed out until the log write completes.
- */
-STATIC void
-xfs_trans_fill_vecs(
-	xfs_trans_t		*tp,
-	xfs_log_iovec_t		*log_vector)
-{
-	xfs_log_item_desc_t	*lidp;
-	xfs_log_iovec_t		*vecp;
-	uint			nitems;
-
-	/*
-	 * Skip over the entry for the transaction header, we'll
-	 * fill that in at the end.
-	 */
-	vecp = log_vector + 1;		/* pointer arithmetic */
-
-	nitems = 0;
-	lidp = xfs_trans_first_item(tp);
-	ASSERT(lidp != NULL);
-	while (lidp != NULL) {
-		/*
-		 * Skip items which aren't dirty in this transaction.
-		 */
-		if (!(lidp->lid_flags & XFS_LID_DIRTY)) {
-			lidp = xfs_trans_next_item(tp, lidp);
-			continue;
-		}
-		/*
-		 * The item may be marked dirty but not log anything.
-		 * This can be used to get called when a transaction
-		 * is committed.
-		 */
-		if (lidp->lid_size) {
-			nitems++;
-		}
-		IOP_FORMAT(lidp->lid_item, vecp);
-		vecp += lidp->lid_size;		/* pointer arithmetic */
-		IOP_PIN(lidp->lid_item);
-		lidp = xfs_trans_next_item(tp, lidp);
-	}
-
-	/*
-	 * Now that we've counted the number of items in this
-	 * transaction, fill in the transaction header.
-	 */
-	tp->t_header.th_magic = XFS_TRANS_HEADER_MAGIC;
-	tp->t_header.th_type = tp->t_type;
-	tp->t_header.th_num_items = nitems;
-	log_vector->i_addr = (xfs_caddr_t)&tp->t_header;
-	log_vector->i_len = sizeof(xfs_trans_header_t);
-	log_vector->i_type = XLOG_REG_TYPE_TRANSHDR;
-}
-
-
-/*
  * Unlock all of the transaction's items and free the transaction.
  * The transaction must not have modified any of its items, because
  * there is no way to restore them to their previous state.
-- 
1.6.5

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[PATCH 6/9] xfs: update and factor xfs_trans_committed()

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

The function header to xfs-trans_committed has long had this
comment:

 * THIS SHOULD BE REWRITTEN TO USE xfs_trans_next_item()

To prepare for different methods of committing items, convert the
code to use xfs_trans_next_item() and factor the code into smaller,
more digestible chunks.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_trans.c |  225 ++++++++++++++++++++++------------------------------
 1 files changed, 96 insertions(+), 129 deletions(-)

diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index ac9af40..abc9874 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -49,7 +49,6 @@
 STATIC void	xfs_trans_apply_sb_deltas(xfs_trans_t *);
 STATIC void	xfs_trans_uncommit(xfs_trans_t *, uint);
 STATIC void	xfs_trans_committed(xfs_trans_t *, int);
-STATIC void	xfs_trans_chunk_committed(xfs_log_item_chunk_t *, xfs_lsn_t, int);
 STATIC void	xfs_trans_free(xfs_trans_t *);
 
 kmem_zone_t	*xfs_trans_zone;
@@ -1296,60 +1295,86 @@ xfs_trans_roll(
 }
 
 /*
- * THIS SHOULD BE REWRITTEN TO USE xfs_trans_next_item().
+ * The committed item processing consists of calling the committed routine of
+ * each logged item, updating the item's position in the AIL if necessary, and
+ * unpinning each item.  If the committed routine returns -1, then do nothing
+ * further with the item because it may have been freed.
  *
- * This is typically called by the LM when a transaction has been fully
- * committed to disk.  It needs to unpin the items which have
- * been logged by the transaction and update their positions
- * in the AIL if necessary.
- * This also gets called when the transactions didn't get written out
- * because of an I/O error. Abortflag & XFS_LI_ABORTED is set then.
+ * Since items are unlocked when they are copied to the incore log, it is
+ * possible for two transactions to be completing and manipulating the same
+ * item simultaneously.  The AIL lock will protect the lsn field of each item.
+ * The value of this field can never go backwards.
  *
- * Call xfs_trans_chunk_committed() to process the items in
- * each chunk.
+ * We unpin the items after repositioning them in the AIL, because otherwise
+ * they could be immediately flushed and we'd have to race with the flusher
+ * trying to pull the item from the AIL as we add it.
  */
-STATIC void
-xfs_trans_committed(
-	xfs_trans_t	*tp,
-	int		abortflag)
+static void
+xfs_trans_item_committed(
+	xfs_log_item_t	*lip,
+	xfs_lsn_t	commit_lsn,
+	int		aborted)
 {
-	xfs_log_item_chunk_t	*licp;
-	xfs_log_item_chunk_t	*next_licp;
-	xfs_log_busy_chunk_t	*lbcp;
-	xfs_log_busy_slot_t	*lbsp;
-	int			i;
+	xfs_lsn_t	item_lsn;
+	struct xfs_ail	*ailp;
+
+	if (aborted)
+		lip->li_flags |= XFS_LI_ABORTED;
 
 	/*
-	 * Call the transaction's completion callback if there
-	 * is one.
+	 * Send in the ABORTED flag to the COMMITTED routine so that it knows
+	 * whether the transaction was aborted or not.
 	 */
-	if (tp->t_callback != NULL) {
-		tp->t_callback(tp, tp->t_callarg);
-	}
+	item_lsn = IOP_COMMITTED(lip, commit_lsn);
 
 	/*
-	 * Special case the chunk embedded in the transaction.
+	 * If the committed routine returns -1, item has been freed.
 	 */
-	licp = &(tp->t_items);
-	if (!(xfs_lic_are_all_free(licp))) {
-		xfs_trans_chunk_committed(licp, tp->t_lsn, abortflag);
-	}
+	if (XFS_LSN_CMP(item_lsn, (xfs_lsn_t)-1) == 0)
+		return;
 
 	/*
-	 * Process the items in each chunk in turn.
+	 * If the returned lsn is greater than what it contained before, update
+	 * the location of the item in the AIL.  If it is not, then do nothing.
+	 * Items can never move backwards in the AIL.
+	 *
+	 * While the new lsn should usually be greater, it is possible that a
+	 * later transaction completing simultaneously with an earlier one
+	 * using the same item could complete first with a higher lsn.  This
+	 * would cause the earlier transaction to fail the test below.
 	 */
-	licp = licp->lic_next;
-	while (licp != NULL) {
-		ASSERT(!xfs_lic_are_all_free(licp));
-		xfs_trans_chunk_committed(licp, tp->t_lsn, abortflag);
-		next_licp = licp->lic_next;
-		kmem_free(licp);
-		licp = next_licp;
+	ailp = lip->li_ailp;
+	spin_lock(&ailp->xa_lock);
+	if (XFS_LSN_CMP(item_lsn, lip->li_lsn) > 0) {
+		/*
+		 * This will set the item's lsn to item_lsn and update the
+		 * position of the item in the AIL.
+		 *
+		 * xfs_trans_ail_update() drops the AIL lock.
+		 */
+		xfs_trans_ail_update(ailp, lip, item_lsn);
+	} else {
+		spin_unlock(&ailp->xa_lock);
 	}
 
 	/*
-	 * Clear all the per-AG busy list items listed in this transaction
+	 * Now that we've repositioned the item in the AIL, unpin it so it can
+	 * be flushed. Pass information about buffer stale state down from the
+	 * log item flags, if anyone else stales the buffer we do not want to
+	 * pay any attention to it.
 	 */
+	IOP_UNPIN(lip);
+}
+
+/* Clear all the per-AG busy list items listed in this transaction */
+static void
+xfs_trans_clear_busy_extents(
+	struct xfs_trans	*tp)
+{
+	xfs_log_busy_chunk_t	*lbcp;
+	xfs_log_busy_slot_t	*lbsp;
+	int			i;
+
 	lbcp = &tp->t_busy;
 	while (lbcp != NULL) {
 		for (i = 0, lbsp = lbcp->lbc_busy; i < lbcp->lbc_unused; i++, lbsp++) {
@@ -1361,107 +1386,49 @@ xfs_trans_committed(
 		lbcp = lbcp->lbc_next;
 	}
 	xfs_trans_free_busy(tp);
-
-	/*
-	 * That's it for the transaction structure.  Free it.
-	 */
-	xfs_trans_free(tp);
 }
 
 /*
- * This is called to perform the commit processing for each
- * item described by the given chunk.
- *
- * The commit processing consists of unlocking items which were
- * held locked with the SYNC_UNLOCK attribute, calling the committed
- * routine of each logged item, updating the item's position in the AIL
- * if necessary, and unpinning each item.  If the committed routine
- * returns -1, then do nothing further with the item because it
- * may have been freed.
- *
- * Since items are unlocked when they are copied to the incore
- * log, it is possible for two transactions to be completing
- * and manipulating the same item simultaneously.  The AIL lock
- * will protect the lsn field of each item.  The value of this
- * field can never go backwards.
+ * This is typically called by the LM when a transaction has been fully
+ * committed to disk.  It needs to unpin the items which have
+ * been logged by the transaction and update their positions
+ * in the AIL if necessary.
  *
- * We unpin the items after repositioning them in the AIL, because
- * otherwise they could be immediately flushed and we'd have to race
- * with the flusher trying to pull the item from the AIL as we add it.
+ * This also gets called when the transactions didn't get written out
+ * because of an I/O error. Abortflag & XFS_LI_ABORTED is set then.
  */
 STATIC void
-xfs_trans_chunk_committed(
-	xfs_log_item_chunk_t	*licp,
-	xfs_lsn_t		lsn,
-	int			aborted)
+xfs_trans_committed(
+	xfs_trans_t	*tp,
+	int		abortflag)
 {
 	xfs_log_item_desc_t	*lidp;
-	xfs_log_item_t		*lip;
-	xfs_lsn_t		item_lsn;
-	int			i;
-
-	lidp = licp->lic_descs;
-	for (i = 0; i < licp->lic_unused; i++, lidp++) {
-		struct xfs_ail		*ailp;
-
-		if (xfs_lic_isfree(licp, i)) {
-			continue;
-		}
-
-		lip = lidp->lid_item;
-		if (aborted)
-			lip->li_flags |= XFS_LI_ABORTED;
-
-		/*
-		 * Send in the ABORTED flag to the COMMITTED routine
-		 * so that it knows whether the transaction was aborted
-		 * or not.
-		 */
-		item_lsn = IOP_COMMITTED(lip, lsn);
+	xfs_log_item_chunk_t	*licp;
+	xfs_log_item_chunk_t	*next_licp;
 
-		/*
-		 * If the committed routine returns -1, make
-		 * no more references to the item.
-		 */
-		if (XFS_LSN_CMP(item_lsn, (xfs_lsn_t)-1) == 0) {
-			continue;
-		}
+	/*
+	 * Call the transaction's completion callback if there
+	 * is one.
+	 */
+	if (tp->t_callback != NULL) {
+		tp->t_callback(tp, tp->t_callarg);
+	}
 
-		/*
-		 * If the returned lsn is greater than what it
-		 * contained before, update the location of the
-		 * item in the AIL.  If it is not, then do nothing.
-		 * Items can never move backwards in the AIL.
-		 *
-		 * While the new lsn should usually be greater, it
-		 * is possible that a later transaction completing
-		 * simultaneously with an earlier one using the
-		 * same item could complete first with a higher lsn.
-		 * This would cause the earlier transaction to fail
-		 * the test below.
-		 */
-		ailp = lip->li_ailp;
-		spin_lock(&ailp->xa_lock);
-		if (XFS_LSN_CMP(item_lsn, lip->li_lsn) > 0) {
-			/*
-			 * This will set the item's lsn to item_lsn
-			 * and update the position of the item in
-			 * the AIL.
-			 *
-			 * xfs_trans_ail_update() drops the AIL lock.
-			 */
-			xfs_trans_ail_update(ailp, lip, item_lsn);
-		} else {
-			spin_unlock(&ailp->xa_lock);
-		}
+	for (lidp = xfs_trans_first_item(tp);
+	     lidp != NULL;
+	     lidp = xfs_trans_next_item(tp, lidp)) {
+		xfs_trans_item_committed(lidp->lid_item, tp->t_lsn, abortflag);
+	}
 
-		/*
-		 * Now that we've repositioned the item in the AIL,
-		 * unpin it so it can be flushed. Pass information
-		 * about buffer stale state down from the log item
-		 * flags, if anyone else stales the buffer we do not
-		 * want to pay any attention to it.
-		 */
-		IOP_UNPIN(lip);
+	/* free the item chunks, ignoring the embedded chunk */
+	licp = tp->t_items.lic_next;
+	while (licp != NULL) {
+		next_licp = licp->lic_next;
+		ASSERT(xfs_lic_are_all_free(licp));
+		kmem_free(licp);
+		licp = next_licp;
 	}
+
+	xfs_trans_clear_busy_extents(tp);
+	xfs_trans_free(tp);
 }
-- 
1.6.5

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[PATCH 7/9] xfs: log ticket reservation underestimates the number of iclogs

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

When allocation a ticket for a transaction, the ticket is initialised with the
worst case log space usage based on the number of bytes the transaction may
consume. Part of this calculation is the number of log headers required for the
iclog space used up by the transaction.

This calculation makes an undocumented assumption that if the transaction uses
the log header space reservation on an iclog, then it consumes either the
entire iclog or it completes. That is - the transaction that is first in an
iclog is the transaction that the log header reservation is accounted to. If
the transaction is larger than the iclog, then it will use the entire iclog
itself. Document this assumption.

Further, the current calculation uses the rule that we can fit iclog_size bytes
of transaction data into an iclog. This is in correct - the amount of space
available in an iclog for transaction data is the size of the iclog minus the
space used for log record headers. This means that the calculation is out by
512 bytes per 32k of log space the transaction can consume. This is rarely an
issue because maximally sized transactions are extremely uncommon, and for 4k
block size filesystems maximal transaction reservations are about 400kb. Hence
the error in this case is less than the size of an iclog, so that makes it even
harder to hit.

However, anyone using larger directory blocks (16k directory blocks push the
maximum transaction size to approx. 900k on a 4k block size filesystem) or
larger block size (e.g. 64k blocks push transactions to the 3-4MB size) could
see the error grow to more than an iclog and at this point the transaction is
guaranteed to get a reservation underrun and shutdown the filesystem.

Fix this by adjusting the calculation to calculate the correct number of iclogs
required and account for them all up front.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_log.c |   55 +++++++++++++++++++++++++++++++++++++++++------------
 1 files changed, 42 insertions(+), 13 deletions(-)

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 1f26a97..7c6b0cd 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -664,7 +664,10 @@ xfs_log_item_init(
 /*
  * Write region vectors to log.  The write happens using the space reservation
  * of the ticket (tic).  It is not a requirement that all writes for a given
- * transaction occur with one call to xfs_log_write().
+ * transaction occur with one call to xfs_log_write(). However, it is important
+ * to note that the transaction reservation code makes an assumption about the
+ * number of log headers a transaction requires that may be violated if you
+ * don't pass all the transaction vectors in one call....
  */
 int
 xfs_log_write(
@@ -3156,14 +3159,16 @@ xfs_log_ticket_get(
  * Allocate and initialise a new log ticket.
  */
 STATIC xlog_ticket_t *
-xlog_ticket_alloc(xlog_t		*log,
-		int		unit_bytes,
-		int		cnt,
-		char		client,
-		uint		xflags)
+xlog_ticket_alloc(
+	struct log	*log,
+	int		unit_bytes,
+	int		cnt,
+	char		client,
+	uint		xflags)
 {
-	xlog_ticket_t	*tic;
+	struct xlog_ticket *tic;
 	uint		num_headers;
+	int		iclog_space;
 
 	tic = kmem_zone_zalloc(xfs_log_ticket_zone, KM_SLEEP|KM_MAYFAIL);
 	if (!tic)
@@ -3207,16 +3212,40 @@ xlog_ticket_alloc(xlog_t		*log,
 	/* for start-rec */
 	unit_bytes += sizeof(xlog_op_header_t);
 
-	/* for LR headers */
-	num_headers = ((unit_bytes + log->l_iclog_size-1) >> log->l_iclog_size_log);
+	/*
+	 * for LR headers - the space for data in an iclog is the size minus
+	 * the space used for the headers. If we use the iclog size, then we
+	 * undercalculate the number of headers required.
+	 *
+	 * Furthermore - the addition of op headers for split-recs might
+	 * increase the space required enough to require more log and op
+	 * headers, so take that into account too.
+	 *
+	 * IMPORTANT: This reservation makes the assumption that if this
+	 * transaction is the first in an iclog and hence has the LR headers
+	 * accounted to it, then the remaining space in the iclog is
+	 * exclusively for this transaction.  i.e. if the transaction is larger
+	 * than the iclog, it will be the only thing in that iclog.
+	 * Fundamentally, this means we must pass the entire log vector to
+	 * xlog_write to guarantee this.
+	 */
+	iclog_space = log->l_iclog_size - log->l_iclog_hsize;
+	num_headers = (unit_bytes + iclog_space - 1) / iclog_space;
+
+	/* for split-recs - ophdrs added when data split over LRs */
+	unit_bytes += sizeof(xlog_op_header_t) * num_headers;
+
+	/* add extra header reservations if we overrun */
+	while (!num_headers ||
+	       ((unit_bytes + iclog_space - 1) / iclog_space) > num_headers) {
+		unit_bytes += sizeof(xlog_op_header_t);
+		num_headers++;
+	}
 	unit_bytes += log->l_iclog_hsize * num_headers;
 
 	/* for commit-rec LR header - note: padding will subsume the ophdr */
 	unit_bytes += log->l_iclog_hsize;
 
-	/* for split-recs - ophdrs added when data split over LRs */
-	unit_bytes += sizeof(xlog_op_header_t) * num_headers;
-
 	/* for roundoff padding for transaction data and one for commit record */
 	if (xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
 	    log->l_mp->m_sb.sb_logsunit > 1) {
@@ -3238,7 +3267,7 @@ xlog_ticket_alloc(xlog_t		*log,
 	tic->t_trans_type	= 0;
 	if (xflags & XFS_LOG_PERM_RESERV)
 		tic->t_flags |= XLOG_TIC_PERM_RESERV;
-	sv_init(&(tic->t_wait), SV_DEFAULT, "logtick");
+	sv_init(&tic->t_wait, SV_DEFAULT, "logtick");
 
 	xlog_tic_reset_res(tic);
 
-- 
1.6.5

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[PATCH 8/9] xfs: introduce new internal log vector structure

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

The current log IO vector structure is a flat array and not
extensible. To make it possible to keep separate log IO vectors for
individual log items, we need a method of chaining log IO vectors
together.

Introduce a new log vector type that can be used to wrap the
existing log IO vectors on use that internally to the log. This
means that the existing external interface (xfs_log_write) does not
change and hence no changes to the transaction commit code are
required.

This initial use of the new log vectors does not use the chaining
capability of the new log vector structure - it is not needed to
implement the flat vector array the current transaction commit path
creates.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_log.c |  106 +++++++++++++++++++++++++++++++-----------------------
 fs/xfs/xfs_log.h |    6 +++
 2 files changed, 67 insertions(+), 45 deletions(-)

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 7c6b0cd..afb27cf 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -50,7 +50,7 @@ kmem_zone_t	*xfs_log_ticket_zone;
 	  (off) += (bytes);}
 
 /* Local miscellaneous function prototypes */
-STATIC int	 xlog_commit_record(xfs_mount_t *mp, xlog_ticket_t *ticket,
+STATIC int	 xlog_commit_record(struct log *log, struct xlog_ticket *ticket,
 				    xlog_in_core_t **, xfs_lsn_t *);
 STATIC xlog_t *  xlog_alloc_log(xfs_mount_t	*mp,
 				xfs_buftarg_t	*log_target,
@@ -59,11 +59,9 @@ STATIC xlog_t *  xlog_alloc_log(xfs_mount_t	*mp,
 STATIC int	 xlog_space_left(xlog_t *log, int cycle, int bytes);
 STATIC int	 xlog_sync(xlog_t *log, xlog_in_core_t *iclog);
 STATIC void	 xlog_dealloc_log(xlog_t *log);
-STATIC int	 xlog_write(xfs_mount_t *mp, xfs_log_iovec_t region[],
-			    int nentries, struct xlog_ticket *tic,
-			    xfs_lsn_t *start_lsn,
-			    xlog_in_core_t **commit_iclog,
-			    uint flags);
+STATIC int	 xlog_write(struct log *log, struct xfs_log_vec *log_vector,
+			    struct xlog_ticket *tic, xfs_lsn_t *start_lsn,
+			    xlog_in_core_t **commit_iclog, uint flags);
 
 /* local state machine functions */
 STATIC void xlog_state_done_syncing(xlog_in_core_t *iclog, int);
@@ -258,7 +256,7 @@ xfs_log_done(
 	     * If we get an error, just continue and give back the log ticket.
 	     */
 	    (((ticket->t_flags & XLOG_TIC_INITED) == 0) &&
-	     (xlog_commit_record(mp, ticket, iclog, &lsn)))) {
+	     (xlog_commit_record(log, ticket, iclog, &lsn)))) {
 		lsn = (xfs_lsn_t) -1;
 		if (ticket->t_flags & XLOG_TIC_PERM_RESERV) {
 			flags |= XFS_LOG_REL_PERM_RESERV;
@@ -516,18 +514,10 @@ xfs_log_unmount_write(xfs_mount_t *mp)
 #ifdef DEBUG
 	xlog_in_core_t	 *first_iclog;
 #endif
-	xfs_log_iovec_t  reg[1];
 	xlog_ticket_t	*tic = NULL;
 	xfs_lsn_t	 lsn;
 	int		 error;
 
-	/* the data section must be 32 bit size aligned */
-	struct {
-	    __uint16_t magic;
-	    __uint16_t pad1;
-	    __uint32_t pad2; /* may as well make it 64 bits */
-	} magic = { XLOG_UNMOUNT_TYPE, 0, 0 };
-
 	/*
 	 * Don't write out unmount record on read-only mounts.
 	 * Or, if we are doing a forced umount (typically because of IO errors).
@@ -549,16 +539,31 @@ xfs_log_unmount_write(xfs_mount_t *mp)
 	} while (iclog != first_iclog);
 #endif
 	if (! (XLOG_FORCED_SHUTDOWN(log))) {
-		reg[0].i_addr = (void*)&magic;
-		reg[0].i_len  = sizeof(magic);
-		reg[0].i_type = XLOG_REG_TYPE_UNMOUNT;
-
 		error = xfs_log_reserve(mp, 600, 1, &tic,
 					XFS_LOG, 0, XLOG_UNMOUNT_REC_TYPE);
 		if (!error) {
+			/* the data section must be 32 bit size aligned */
+			struct {
+			    __uint16_t magic;
+			    __uint16_t pad1;
+			    __uint32_t pad2; /* may as well make it 64 bits */
+			} magic = {
+				.magic = XLOG_UNMOUNT_TYPE,
+			};
+			struct xfs_log_iovec reg = {
+				.i_addr = (void *)&magic,
+				.i_len = sizeof(magic),
+				.i_type = XLOG_REG_TYPE_UNMOUNT,
+			};
+			struct xfs_log_vec vec = {
+				.lv_niovecs = 1,
+			};
+			/* sigh. c99 initialisers don't work on anon unions */
+			vec.lv_iovecp = &reg;
+
 			/* remove inited flag */
-			((xlog_ticket_t *)tic)->t_flags = 0;
-			error = xlog_write(mp, reg, 1, tic, &lsn,
+			tic->t_flags = 0;
+			error = xlog_write(log, &vec, tic, &lsn,
 					   NULL, XLOG_UNMOUNT_TRANS);
 			/*
 			 * At this point, we're umounting anyway,
@@ -679,11 +684,16 @@ xfs_log_write(
 {
 	struct log		*log = mp->m_log;
 	int			error;
+	struct xfs_log_vec	vec = {
+		.lv_niovecs = nentries,
+	};
+	/* sigh. c99 initialisers don't work on anon unions */
+	vec.lv_iovecp = reg;
 
 	if (XLOG_FORCED_SHUTDOWN(log))
 		return XFS_ERROR(EIO);
 
-	error = xlog_write(mp, reg, nentries, tic, start_lsn, NULL, 0);
+	error = xlog_write(log, &vec, tic, start_lsn, NULL, 0);
 	if (error)
 		xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
 	return error;
@@ -1176,26 +1186,32 @@ out:
  * ticket.  Return the lsn of the commit record.
  */
 STATIC int
-xlog_commit_record(xfs_mount_t  *mp,
-		   xlog_ticket_t *ticket,
-		   xlog_in_core_t **iclog,
-		   xfs_lsn_t	*commitlsnp)
+xlog_commit_record(
+	struct log		*log,
+	struct xlog_ticket	*ticket,
+	struct xlog_in_core	**iclog,
+	xfs_lsn_t		*commitlsnp)
 {
-	int		error;
-	xfs_log_iovec_t	reg[1];
-
-	reg[0].i_addr = NULL;
-	reg[0].i_len = 0;
-	reg[0].i_type = XLOG_REG_TYPE_COMMIT;
+	struct xfs_mount *mp = log->l_mp;
+	int	error;
+	struct xfs_log_iovec reg = {
+		.i_addr = NULL,
+		.i_len = 0,
+		.i_type = XLOG_REG_TYPE_COMMIT,
+	};
+	struct xfs_log_vec vec = {
+		.lv_niovecs = 1,
+	};
+	/* sigh. c99 initialisers don't work on anon unions */
+	vec.lv_iovecp = &reg;
 
 	ASSERT_ALWAYS(iclog);
-	if ((error = xlog_write(mp, reg, 1, ticket, commitlsnp,
-			       iclog, XLOG_COMMIT_TRANS))) {
+	error = xlog_write(log, &vec, ticket, commitlsnp, iclog,
+					XLOG_COMMIT_TRANS);
+	if (error)
 		xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
-	}
 	return error;
-}	/* xlog_commit_record */
-
+}
 
 /*
  * Push on the buffer cache code if we ever use more than 75% of the on-disk
@@ -1657,15 +1673,13 @@ xlog_print_tic_res(xfs_mount_t *mp, xlog_ticket_t *ticket)
  */
 STATIC int
 xlog_write(
-	struct xfs_mount	*mp,
-	struct xfs_log_iovec	reg[],
-	int			nentries,
+	struct log		*log,
+	struct xfs_log_vec	*log_vector,
 	struct xlog_ticket	*ticket,
 	xfs_lsn_t		*start_lsn,
 	struct xlog_in_core	**commit_iclog,
 	uint			flags)
 {
-    xlog_t	     *log = mp->m_log;
     xlog_in_core_t   *iclog = NULL;  /* ptr to current in-core log */
     xlog_op_header_t *logop_head;    /* ptr to log operation header */
     __psint_t	     ptr;	     /* copy address into data region */
@@ -1681,6 +1695,8 @@ xlog_write(
     int		     contwr;	     /* continued write of in-core log? */
     int		     error;
     int		     record_cnt = 0, data_cnt = 0;
+    struct xfs_log_iovec *reg = log_vector->lv_iovecp;
+    int		     nentries = log_vector->lv_niovecs;
 
     partial_copy_len = partial_copy = 0;
 
@@ -1702,16 +1718,16 @@ xlog_write(
     contwr = *start_lsn = 0;
 
     if (ticket->t_curr_res < len) {
-	xlog_print_tic_res(mp, ticket);
+	xlog_print_tic_res(log->l_mp, ticket);
 #ifdef DEBUG
 	xlog_panic(
 		"xfs_log_write: reservation ran out. Need to up reservation");
 #else
 	/* Customer configurable panic */
-	xfs_cmn_err(XFS_PTAG_LOGRES, CE_ALERT, mp,
+	xfs_cmn_err(XFS_PTAG_LOGRES, CE_ALERT, log->l_mp,
 		"xfs_log_write: reservation ran out. Need to up reservation");
 	/* If we did not panic, shutdown the filesystem */
-	xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
+	xfs_force_shutdown(log->l_mp, SHUTDOWN_CORRUPT_INCORE);
 #endif
     } else
 	ticket->t_curr_res -= len;
@@ -1777,7 +1793,7 @@ xlog_write(
 	    case XFS_LOG:
 		break;
 	    default:
-		xfs_fs_cmn_err(CE_WARN, mp,
+		xfs_fs_cmn_err(CE_WARN, log->l_mp,
 		    "Bad XFS transaction clientid 0x%x in ticket 0x%p",
 		    logop_head->oh_clientid, ticket);
 		return XFS_ERROR(EIO);
diff --git a/fs/xfs/xfs_log.h b/fs/xfs/xfs_log.h
index f3a564d..229d1f3 100644
--- a/fs/xfs/xfs_log.h
+++ b/fs/xfs/xfs_log.h
@@ -110,6 +110,12 @@ typedef struct xfs_log_iovec {
 	uint		i_type;		/* type of region */
 } xfs_log_iovec_t;
 
+struct xfs_log_vec {
+	struct xfs_log_vec	*lv_next;	/* next lv in build list */
+	int			lv_niovecs;	/* number of iovecs in lv */
+	struct xfs_log_iovec	*lv_iovecp;	/* iovec array */
+};
+
 /*
  * Structure used to pass callback function and the function's argument
  * to the log manager.
-- 
1.6.5

_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs

[PATCH 9/9] xfs: factor xlog_write and make use of new log vector structure

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

xlog_write is a mess that takes a lot of effort to understand. It is
a mass of nested loops with 4 space indents to get it to fit in 80 columns
and lots of funky variables that aren't obvious what they mean or do.

Break it down into understandable chunks, format them properly and propagate
the new log vector structure into it to support chaining of log vectors.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_log.c |  503 ++++++++++++++++++++++++++++++++++--------------------
 1 files changed, 318 insertions(+), 185 deletions(-)

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index afb27cf..38b4dc4 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -1632,6 +1632,193 @@ xlog_print_tic_res(xfs_mount_t *mp, xlog_ticket_t *ticket)
 }
 
 /*
+ * Calculate the potential space needed by the log vector.  Each region gets
+ * its own xlog_op_header_t and may need to be double word aligned. If regions
+ * get split, we'll account for the extra headers then.
+ */
+static int
+xlog_write_calc_vec_length(
+	struct xlog_ticket *ticket,
+	struct xfs_log_vec *log_vector)
+{
+	struct xfs_log_vec *lv;
+	int		headers = 0;
+	int		len = 0;
+	int		index;
+
+	if (ticket->t_flags & XLOG_TIC_INITED)
+		headers++;
+
+	for (lv = log_vector; lv; lv = lv->lv_next) {
+		struct xfs_log_iovec	*vecp;
+
+		headers += lv->lv_niovecs;
+		vecp = lv->lv_iovecp;
+		for (index = 0; index < lv->lv_niovecs; index++) {
+			len += vecp->i_len;
+			xlog_tic_add_region(ticket, vecp->i_len, vecp->i_type);
+			vecp++;
+		}
+	}
+
+	ticket->t_res_num_ophdrs += headers;
+	len += headers * sizeof(xlog_op_header_t);
+
+	return len;
+}
+
+/*
+ * If first write for transaction, insert start record.  We can't be trying to
+ * commit if we are inited.  We can't have any "partial_copy" if we are inited.
+ */
+static int
+xlog_write_start_rec(
+	__psint_t	ptr,
+	xlog_ticket_t	*ticket)
+{
+	xlog_op_header_t *logop_head;
+
+	if (!(ticket->t_flags & XLOG_TIC_INITED))
+		return 0;
+	logop_head = (xlog_op_header_t *)ptr;
+	logop_head->oh_tid = cpu_to_be32(ticket->t_tid);
+	logop_head->oh_clientid = ticket->t_clientid;
+	logop_head->oh_len = 0;
+	logop_head->oh_flags = XLOG_START_TRANS;
+	logop_head->oh_res2 = 0;
+	ticket->t_flags &= ~XLOG_TIC_INITED;
+	return sizeof(xlog_op_header_t);
+}
+
+static xlog_op_header_t *
+xlog_write_setup_ophdr(
+	struct log	*log,
+	__psint_t	ptr,
+	xlog_ticket_t	*ticket,
+	uint		flags)
+{
+	xlog_op_header_t *logop_head;
+
+	/* Copy log operation header directly into data section */
+	logop_head = (xlog_op_header_t *)ptr;
+	logop_head->oh_tid = cpu_to_be32(ticket->t_tid);
+	logop_head->oh_clientid = ticket->t_clientid;
+	logop_head->oh_res2 = 0;
+
+	/* are we copying a commit or unmount record? */
+	logop_head->oh_flags = flags;
+
+	/*
+	 * We've seen logs corrupted with bad transaction client ids.  This
+	 * makes sure that XFS doesn't generate them on.  Turn this into an EIO
+	 * and shut down the filesystem.
+	 */
+	switch (logop_head->oh_clientid)  {
+	case XFS_TRANSACTION:
+	case XFS_VOLUME:
+	case XFS_LOG:
+		break;
+	default:
+		xfs_fs_cmn_err(CE_WARN, log->l_mp,
+			"Bad XFS transaction clientid 0x%x in ticket 0x%p",
+			logop_head->oh_clientid, ticket);
+		return NULL;
+	}
+	return logop_head;
+}
+
+
+/*
+ * Set up the parameters of the region copy into the log. This has
+ * to handle region write split across multiple log buffers - this
+ * state is kept external to this function so that this code can
+ * can be written in an obvious, self documenting manner.
+ */
+static int
+xlog_write_setup_copy(
+	xlog_ticket_t	*ticket,
+	xlog_op_header_t *ophdr,
+	int		space_available,
+	int		space_required,
+	int		*copy_off,
+	int		*copy_len,
+	int		*last_was_partial_copy,
+	int		*bytes_consumed)
+{
+	int	still_to_copy;
+
+	still_to_copy = space_required - *bytes_consumed;
+	*copy_off = *bytes_consumed;
+
+	if (still_to_copy <= space_available) {
+		/* write of region completes here */
+		*copy_len = still_to_copy;
+		ophdr->oh_len = cpu_to_be32(*copy_len);
+		if (*last_was_partial_copy)
+			ophdr->oh_flags |= (XLOG_END_TRANS|XLOG_WAS_CONT_TRANS);
+		*last_was_partial_copy = 0;
+		*bytes_consumed = 0;
+		return 0;
+	}
+
+	/* partial write of region, needs extra log op header reservation */
+	*copy_len = space_available;
+	ophdr->oh_len = cpu_to_be32(*copy_len);
+	ophdr->oh_flags |= XLOG_CONTINUE_TRANS;
+	if (*last_was_partial_copy)
+		ophdr->oh_flags |= XLOG_WAS_CONT_TRANS;
+	*bytes_consumed += *copy_len;
+	(*last_was_partial_copy)++;
+	ticket->t_curr_res -= sizeof(xlog_op_header_t);
+	ticket->t_res_num_ophdrs++;
+	return sizeof(xlog_op_header_t);
+}
+
+static int
+xlog_write_copy_finish(
+	xlog_t		*log,
+	xlog_in_core_t	*iclog,
+	uint		flags,
+	int		*record_cnt,
+	int		*data_cnt,
+	int		*partial_copy,
+	int		*partial_copy_len,
+	int		log_offset,
+	xlog_in_core_t	**commit_iclog)
+{
+	if (*partial_copy) {
+		/*
+		 * iclog has already been marked WANT_SYNC by
+		 * xlog_state_get_iclog_space
+		 */
+		xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
+		*record_cnt = 0;
+		*data_cnt = 0;
+		return xlog_state_release_iclog(log, iclog);
+	}
+
+	*partial_copy = 0;
+	*partial_copy_len = 0;
+
+	if (iclog->ic_size - log_offset <= sizeof(xlog_op_header_t)) {
+		/* no more space in this iclog - push it. */
+		xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
+		*record_cnt = 0;
+		*data_cnt = 0;
+
+		spin_lock(&log->l_icloglock);
+		xlog_state_want_sync(log, iclog);
+		spin_unlock(&log->l_icloglock);
+
+		if (!commit_iclog)
+			return xlog_state_release_iclog(log, iclog);
+		ASSERT(flags & XLOG_COMMIT_TRANS);
+		*commit_iclog = iclog;
+	}
+	return 0;
+}
+
+/*
  * Write some region out to in-core log
  *
  * This will be called when writing externally provided regions or when
@@ -1680,203 +1867,149 @@ xlog_write(
 	struct xlog_in_core	**commit_iclog,
 	uint			flags)
 {
-    xlog_in_core_t   *iclog = NULL;  /* ptr to current in-core log */
-    xlog_op_header_t *logop_head;    /* ptr to log operation header */
-    __psint_t	     ptr;	     /* copy address into data region */
-    int		     len;	     /* # xlog_write() bytes 2 still copy */
-    int		     index;	     /* region index currently copying */
-    int		     log_offset;     /* offset (from 0) into data region */
-    int		     start_rec_copy; /* # bytes to copy for start record */
-    int		     partial_copy;   /* did we split a region? */
-    int		     partial_copy_len;/* # bytes copied if split region */
-    int		     need_copy;	     /* # bytes need to memcpy this region */
-    int		     copy_len;	     /* # bytes actually memcpy'ing */
-    int		     copy_off;	     /* # bytes from entry start */
-    int		     contwr;	     /* continued write of in-core log? */
-    int		     error;
-    int		     record_cnt = 0, data_cnt = 0;
-    struct xfs_log_iovec *reg = log_vector->lv_iovecp;
-    int		     nentries = log_vector->lv_niovecs;
-
-    partial_copy_len = partial_copy = 0;
-
-    /* Calculate potential maximum space.  Each region gets its own
-     * xlog_op_header_t and may need to be double word aligned.
-     */
-    len = 0;
-    if (ticket->t_flags & XLOG_TIC_INITED) {    /* acct for start rec of xact */
-	len += sizeof(xlog_op_header_t);
-	ticket->t_res_num_ophdrs++;
-    }
-
-    for (index = 0; index < nentries; index++) {
-	len += sizeof(xlog_op_header_t);	    /* each region gets >= 1 */
-	ticket->t_res_num_ophdrs++;
-	len += reg[index].i_len;
-	xlog_tic_add_region(ticket, reg[index].i_len, reg[index].i_type);
-    }
-    contwr = *start_lsn = 0;
+	xlog_in_core_t	*iclog = NULL;  /* ptr to current in-core log */
+	xlog_op_header_t *logop_head;	/* ptr to log operation header */
+	struct xfs_log_iovec *vecp;
+	struct xfs_log_vec *lv;
+	__psint_t	ptr;		/* copy address into data region */
+	int		len = 0;	/* # xlog_write() bytes 2 still copy */
+	int		index;		/* region index currently copying */
+	int		log_offset;	/* offset (from 0) into data region */
+	int		start_rec_copy;	/* # bytes to copy for start record */
+	int		partial_copy;	/* did we split a region? */
+	int		partial_copy_len;/* # bytes copied if split region */
+	int		copy_len;	/* # bytes actually memcpy'ing */
+	int		copy_off;	/* # bytes from entry start */
+	int		contwr = 0;	/* continued write of in-core log? */
+	int		error = 0;
+	int		record_cnt = 0;
+	int		data_cnt = 0;
+
+	partial_copy_len = partial_copy = 0;
+	if (commit_iclog)
+		*commit_iclog = NULL;
+
+	len += xlog_write_calc_vec_length(ticket, log_vector);
 
-    if (ticket->t_curr_res < len) {
-	xlog_print_tic_res(log->l_mp, ticket);
+	ticket->t_curr_res -= len;
+	if (ticket->t_curr_res < 0) {
+		xlog_print_tic_res(log->l_mp, ticket);
 #ifdef DEBUG
-	xlog_panic(
-		"xfs_log_write: reservation ran out. Need to up reservation");
+		xlog_panic("xfs_log_write: "
+				"reservation ran out. Need to up reservation");
 #else
-	/* Customer configurable panic */
-	xfs_cmn_err(XFS_PTAG_LOGRES, CE_ALERT, log->l_mp,
-		"xfs_log_write: reservation ran out. Need to up reservation");
-	/* If we did not panic, shutdown the filesystem */
-	xfs_force_shutdown(log->l_mp, SHUTDOWN_CORRUPT_INCORE);
+		/* Customer configurable panic */
+		xfs_cmn_err(XFS_PTAG_LOGRES, CE_ALERT, log->l_mp,
+				"xfs_log_write: "
+				"reservation ran out. Need to up reservation");
+		/* If we did not panic, shutdown the filesystem */
+		xfs_force_shutdown(log->l_mp, SHUTDOWN_CORRUPT_INCORE);
 #endif
-    } else
-	ticket->t_curr_res -= len;
-
-    for (index = 0; index < nentries; ) {
-	if ((error = xlog_state_get_iclog_space(log, len, &iclog, ticket,
-					       &contwr, &log_offset)))
-		return error;
-
-	ASSERT(log_offset <= iclog->ic_size - 1);
-	ptr = (__psint_t) ((char *)iclog->ic_datap+log_offset);
+	}
 
-	/* start_lsn is the first lsn written to. That's all we need. */
-	if (! *start_lsn)
-	    *start_lsn = be64_to_cpu(iclog->ic_header.h_lsn);
+	index = 0;
+	lv = log_vector;
+	vecp = lv->lv_iovecp;
+	while (lv && index < lv->lv_niovecs) {
 
-	/* This loop writes out as many regions as can fit in the amount
-	 * of space which was allocated by xlog_state_get_iclog_space().
-	 */
-	while (index < nentries) {
-	    ASSERT(reg[index].i_len % sizeof(__int32_t) == 0);
-	    ASSERT((__psint_t)ptr % sizeof(__int32_t) == 0);
-	    start_rec_copy = 0;
-
-	    /* If first write for transaction, insert start record.
-	     * We can't be trying to commit if we are inited.  We can't
-	     * have any "partial_copy" if we are inited.
-	     */
-	    if (ticket->t_flags & XLOG_TIC_INITED) {
-		logop_head		= (xlog_op_header_t *)ptr;
-		logop_head->oh_tid	= cpu_to_be32(ticket->t_tid);
-		logop_head->oh_clientid = ticket->t_clientid;
-		logop_head->oh_len	= 0;
-		logop_head->oh_flags    = XLOG_START_TRANS;
-		logop_head->oh_res2	= 0;
-		ticket->t_flags		&= ~XLOG_TIC_INITED;	/* clear bit */
-		record_cnt++;
-
-		start_rec_copy = sizeof(xlog_op_header_t);
-		xlog_write_adv_cnt(ptr, len, log_offset, start_rec_copy);
-	    }
+		error = xlog_state_get_iclog_space(log, len, &iclog, ticket,
+						       &contwr, &log_offset);
+		if (error)
+			return error;
 
-	    /* Copy log operation header directly into data section */
-	    logop_head			= (xlog_op_header_t *)ptr;
-	    logop_head->oh_tid		= cpu_to_be32(ticket->t_tid);
-	    logop_head->oh_clientid	= ticket->t_clientid;
-	    logop_head->oh_res2		= 0;
+		ASSERT(log_offset <= iclog->ic_size - 1);
+		ptr = (__psint_t) ((char *)iclog->ic_datap + log_offset);
 
-	    /* header copied directly */
-	    xlog_write_adv_cnt(ptr, len, log_offset, sizeof(xlog_op_header_t));
+		/* start_lsn is the first lsn written to. That's all we need. */
+		if (start_lsn)
+			*start_lsn = be64_to_cpu(iclog->ic_header.h_lsn);
 
-	    /* are we copying a commit or unmount record? */
-	    logop_head->oh_flags = flags;
+		/*
+		 * This loop writes out as many regions as can fit in the amount
+		 * of space which was allocated by xlog_state_get_iclog_space().
+		 */
+		while (lv && index < lv->lv_niovecs) {
+			struct xfs_log_iovec *reg = &vecp[index];
+
+			ASSERT(reg->i_len % sizeof(__int32_t) == 0);
+			ASSERT((__psint_t)ptr % sizeof(__int32_t) == 0);
+			start_rec_copy = 0;
+
+			start_rec_copy = xlog_write_start_rec(ptr, ticket);
+			if (start_rec_copy) {
+				record_cnt++;
+				xlog_write_adv_cnt(ptr, len, log_offset,
+							start_rec_copy);
+			}
 
-	    /*
-	     * We've seen logs corrupted with bad transaction client
-	     * ids.  This makes sure that XFS doesn't generate them on.
-	     * Turn this into an EIO and shut down the filesystem.
-	     */
-	    switch (logop_head->oh_clientid)  {
-	    case XFS_TRANSACTION:
-	    case XFS_VOLUME:
-	    case XFS_LOG:
-		break;
-	    default:
-		xfs_fs_cmn_err(CE_WARN, log->l_mp,
-		    "Bad XFS transaction clientid 0x%x in ticket 0x%p",
-		    logop_head->oh_clientid, ticket);
-		return XFS_ERROR(EIO);
-	    }
+			logop_head = xlog_write_setup_ophdr(log, ptr,
+							ticket, flags);
+			if (!logop_head)
+				return XFS_ERROR(EIO);
+			xlog_write_adv_cnt(ptr, len, log_offset,
+						sizeof(xlog_op_header_t));
+
+			len += xlog_write_setup_copy(ticket, logop_head,
+					iclog->ic_size - log_offset,
+					reg->i_len, &copy_off, &copy_len,
+					&partial_copy, &partial_copy_len);
+
+			xlog_verify_dest_ptr(log, ptr);
+
+			/* copy region */
+			ASSERT(copy_len >= 0);
+			memcpy((void *)ptr, reg->i_addr + copy_off, copy_len);
+			xlog_write_adv_cnt(ptr, len, log_offset, copy_len);
+
+			/* copy_len is total bytes copied, including headers */
+			copy_len += start_rec_copy + sizeof(xlog_op_header_t);
+			record_cnt++;
+			data_cnt += contwr ? copy_len : 0;
+
+			error = xlog_write_copy_finish(log, iclog, flags,
+					&record_cnt, &data_cnt,
+					&partial_copy, &partial_copy_len,
+					log_offset, commit_iclog);
+			if (error)
+				return error;
 
-	    /* Partial write last time? => (partial_copy != 0)
-	     * need_copy is the amount we'd like to copy if everything could
-	     * fit in the current memcpy.
-	     */
-	    need_copy =	reg[index].i_len - partial_copy_len;
-
-	    copy_off = partial_copy_len;
-	    if (need_copy <= iclog->ic_size - log_offset) { /*complete write */
-	        copy_len = need_copy;
-		logop_head->oh_len = cpu_to_be32(copy_len);
-		if (partial_copy)
-		    logop_head->oh_flags|= (XLOG_END_TRANS|XLOG_WAS_CONT_TRANS);
-		partial_copy_len = partial_copy = 0;
-	    } else {					    /* partial write */
-		copy_len = iclog->ic_size - log_offset;
-		logop_head->oh_len = cpu_to_be32(copy_len);
-		logop_head->oh_flags |= XLOG_CONTINUE_TRANS;
-		if (partial_copy)
-			logop_head->oh_flags |= XLOG_WAS_CONT_TRANS;
-		partial_copy_len += copy_len;
-		partial_copy++;
-		len += sizeof(xlog_op_header_t); /* from splitting of region */
-		/* account for new log op header */
-		ticket->t_curr_res -= sizeof(xlog_op_header_t);
-		ticket->t_res_num_ophdrs++;
-	    }
-	    xlog_verify_dest_ptr(log, ptr);
-
-	    /* copy region */
-	    ASSERT(copy_len >= 0);
-	    memcpy((xfs_caddr_t)ptr, reg[index].i_addr + copy_off, copy_len);
-	    xlog_write_adv_cnt(ptr, len, log_offset, copy_len);
-
-	    /* make copy_len total bytes copied, including headers */
-	    copy_len += start_rec_copy + sizeof(xlog_op_header_t);
-	    record_cnt++;
-	    data_cnt += contwr ? copy_len : 0;
-	    if (partial_copy) {			/* copied partial region */
-		    /* already marked WANT_SYNC by xlog_state_get_iclog_space */
-		    xlog_state_finish_copy(log, iclog, record_cnt, data_cnt);
-		    record_cnt = data_cnt = 0;
-		    if ((error = xlog_state_release_iclog(log, iclog)))
-			    return error;
-		    break;			/* don't increment index */
-	    } else {				/* copied entire region */
-		index++;
-		partial_copy_len = partial_copy = 0;
-
-		if (iclog->ic_size - log_offset <= sizeof(xlog_op_header_t)) {
-		    xlog_state_finish_copy(log, iclog, record_cnt, data_cnt);
-		    record_cnt = data_cnt = 0;
-		    spin_lock(&log->l_icloglock);
-		    xlog_state_want_sync(log, iclog);
-		    spin_unlock(&log->l_icloglock);
-		    if (commit_iclog) {
-			ASSERT(flags & XLOG_COMMIT_TRANS);
-			*commit_iclog = iclog;
-		    } else if ((error = xlog_state_release_iclog(log, iclog)))
-			   return error;
-		    if (index == nentries)
-			    return 0;		/* we are done */
-		    else
-			    break;
+			/*
+			 * if we had a partial copy, we need to get more iclog
+			 * space but we don't want to increment the region
+			 * index because there is still more is this region to
+			 * write.
+			 *
+			 * If we completed writing this region, and we flushed
+			 * the iclog (indicated by resetting of the record
+			 * count), then we also need to get more log space. If
+			 * this was the last record, though, we are done and
+			 * can just return.
+			 */
+			if (partial_copy)
+				break;
+			if (++index == lv->lv_niovecs) {
+				lv = lv->lv_next;
+				index = 0;
+				if (lv)
+					vecp = lv->lv_iovecp;
+			}
+			if (record_cnt == 0) {
+				if (!lv)
+					return 0; /* last region, done! */
+				break;
+			}
 		}
-	    } /* if (partial_copy) */
-	} /* while (index < nentries) */
-    } /* for (index = 0; index < nentries; ) */
-    ASSERT(len == 0);
-
-    xlog_state_finish_copy(log, iclog, record_cnt, data_cnt);
-    if (commit_iclog) {
-	ASSERT(flags & XLOG_COMMIT_TRANS);
-	*commit_iclog = iclog;
-	return 0;
-    }
-    return xlog_state_release_iclog(log, iclog);
-}	/* xlog_write */
+	}
+	ASSERT(len == 0);
 
+	xlog_state_finish_copy(log, iclog, record_cnt, data_cnt);
+	if (commit_iclog) {
+		ASSERT(flags & XLOG_COMMIT_TRANS);
+		*commit_iclog = iclog;
+		return 0;
+	}
+	return xlog_state_release_iclog(log, iclog);
+}
 
 /*****************************************************************************
  *
-- 
1.6.5

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Re: [PATCH 1/9] xfs: factor log item initialisation

[Christoph Hellwig]

On Sat, Mar 06, 2010 at 12:51:16PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> Each log item type does manual initialisation of the log item.
> Delayed logging introduce?? new fields that need initialisation, so
> factor all the open coded initialisation into a common function
> first.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>

Looks good.  While not really an obvious cleanup by itself I see where
it comes in useful later.


Reviewed-by: Christoph Hellwig <hch@lst.de>

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Re: [PATCH 2/9] xfs: Add inode pin counts to traces

[Christoph Hellwig]

On Sat, Mar 06, 2010 at 12:51:17PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> We don't record pin counts in inode events right now, and this makes
> it difficult to track down problems related to pinning inodes. Add
> the pin count to the inode trace class and add trace events for
> pinning and unpinning inodes.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>

Looks good.


Reviewed-by: Christoph Hellwig <hch@lst.de>

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Re: [PATCH 4/9] xfs: fix reservation release commit flag in xfs_bmap_add_attrfork()

[Christoph Hellwig]

On Sat, Mar 06, 2010 at 12:51:19PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> xfs_bmap_add_attrfork() passes XFS_TRANS_PERM_LOG_RES to xfs_trans_commit()
> to indicate that the commit should release the permanent log reservation
> as part of the commit. This is wrong - the correct flag is
> XFS_TRANS_RELEASE_LOG_RES - and it is only by the chance that both these
> flags have the value of 0x4 that the code is doing the right thing.
> 
> Fix it by changing to use the correct flag.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>

Looks good,


Reviewed-by: Christoph Hellwig <hch@lst.de>

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Re: [PATCH 3/9] xfs: remove stale parameter from ->iop_unpin method

[Christoph Hellwig]

On Sat, Mar 06, 2010 at 12:51:18PM +1100, Dave Chinner wrote:
> The staleness of a object being unpinned can be directly derived
> from the object itself - there is no need to extract it from the
> object then pass it as a parameter into IOP_UNPIN().

Not quite as obvious as the description makes it sounds, as
we're removing the XFS_LID_BUF_STALE flag, and the buf item
which was the only place actually checking it is now switched
to the XFS_BLI_STALE flag in the xfs_buf_log_item, but as
these are set and cleared in exactly the same places it's fine
and a great cleanups.


Signed-off-by: Christoph Hellwig <hch@lst.de>

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Re: [PATCH 0/9] Log and transaction cleanups, factoring and bug fixes

[Christoph Hellwig]

I went through the simpler ones, and at least 2 and 4, if not 1-4 is
something I'd like to see in 2.6.34 still.

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Re: [PATCH 5/9] xfs: split out iclog writing from xfs_trans_commit()

[Christoph Hellwig]

On Sat, Mar 06, 2010 at 12:51:20PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> Split the the part of xfs_trans_commit() that deals with writing the
> transaction into the iclog into a separate function. This isolates the
> physical commit process from the logical commit operation and makes
> it easier to insert different transaction commit paths without affecting
> the existing algorithm adversely.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>

Looks good, but some comments below:

> +        if (nvec > XFS_TRANS_LOGVEC_COUNT)
> +                kmem_free(log_vector);

These two lines are indented with whitespaces instead of tabs.

> +shut_us_down:
> +	shutdown = XFS_FORCED_SHUTDOWN(mp) ? EIO : 0;
> +	if (!(tp->t_flags & XFS_TRANS_DIRTY) || shutdown) {
> +		xfs_trans_unreserve_and_mod_sb(tp);
> +		/*

This whole area in _xfs_trans_commit is still a complete mess.


What about throwing the patch below in once you're rewriting it anyway?


Index: xfs/fs/xfs/xfs_trans.c
===================================================================
--- xfs.orig/fs/xfs/xfs_trans.c	2010-03-06 12:03:05.567023865 +0100
+++ xfs/fs/xfs/xfs_trans.c	2010-03-06 12:04:47.610255671 +0100
@@ -1020,19 +1020,17 @@ xfs_trans_commit_iclog(
  * have already been unlocked as if the commit had succeeded.
  * Do not reference the transaction structure after this call.
  */
- /*ARGSUSED*/
 int
 _xfs_trans_commit(
-	xfs_trans_t	*tp,
-	uint		flags,
-	int		*log_flushed)
+	struct xfs_trans	*tp,
+	uint			flags,
+	int			*log_flushed)
 {
-	xfs_mount_t		*mp = tp->t_mountp;
+	struct xfs_mount	*mp = tp->t_mountp;
 	xfs_lsn_t		commit_lsn = -1;
-	int			error;
+	int			error = 0;
 	int			log_flags = 0;
 	int			sync = tp->t_flags & XFS_TRANS_SYNC;
-	int			shutdown;
 
 	/*
 	 * Determine whether this commit is releasing a permanent
@@ -1050,30 +1048,14 @@ _xfs_trans_commit(
 	 * Also make sure to return any reserved blocks to
 	 * the free pool.
 	 */
-shut_us_down:
-	shutdown = XFS_FORCED_SHUTDOWN(mp) ? EIO : 0;
-	if (!(tp->t_flags & XFS_TRANS_DIRTY) || shutdown) {
-		xfs_trans_unreserve_and_mod_sb(tp);
-		/*
-		 * It is indeed possible for the transaction to be
-		 * not dirty but the dqinfo portion to be. All that
-		 * means is that we have some (non-persistent) quota
-		 * reservations that need to be unreserved.
-		 */
-		xfs_trans_unreserve_and_mod_dquots(tp);
-		if (tp->t_ticket) {
-			commit_lsn = xfs_log_done(mp, tp->t_ticket,
-							NULL, log_flags);
-			if (commit_lsn == -1 && !shutdown)
-				shutdown = XFS_ERROR(EIO);
-		}
-		current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
-		xfs_trans_free_items(tp, shutdown? XFS_TRANS_ABORT : 0);
-		xfs_trans_free_busy(tp);
-		xfs_trans_free(tp);
-		XFS_STATS_INC(xs_trans_empty);
-		return (shutdown);
+	if (!(tp->t_flags & XFS_TRANS_DIRTY))
+		goto out_unreserve;
+
+	if (XFS_FORCED_SHUTDOWN(mp)) {
+		error = EIO;
+		goto out_unreserve;
 	}
+
 	ASSERT(tp->t_ticket != NULL);
 
 	/*
@@ -1086,7 +1068,8 @@ shut_us_down:
 	error = xfs_trans_commit_iclog(mp, tp, &commit_lsn, flags);
 	if (error == ENOMEM) {
 		xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
-		goto shut_us_down;
+		error = EIO;
+		goto out_unreserve;
 	}
 
 	/*
@@ -1103,7 +1086,29 @@ shut_us_down:
 		XFS_STATS_INC(xs_trans_async);
 	}
 
-	return (error);
+	return error;
+
+out_unreserve:
+	xfs_trans_unreserve_and_mod_sb(tp);
+
+	/*
+	 * It is indeed possible for the transaction to be not dirty but
+	 * the dqinfo portion to be.  All that means is that we have some
+	 * (non-persistent) quota reservations that need to be unreserved.
+	 */
+	xfs_trans_unreserve_and_mod_dquots(tp);
+	if (tp->t_ticket) {
+		commit_lsn = xfs_log_done(mp, tp->t_ticket, NULL, log_flags);
+		if (commit_lsn == -1 && !error)
+			error = XFS_ERROR(EIO);
+	}
+	current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
+	xfs_trans_free_items(tp, error ? XFS_TRANS_ABORT : 0);
+	xfs_trans_free_busy(tp);
+	xfs_trans_free(tp);
+
+	XFS_STATS_INC(xs_trans_empty);
+	return error;
 }
 
 /*

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Re: [PATCH 6/9] xfs: update and factor xfs_trans_committed()

[Christoph Hellwig]

On Sat, Mar 06, 2010 at 12:51:21PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> The function header to xfs-trans_committed has long had this
> comment:
> 
>  * THIS SHOULD BE REWRITTEN TO USE xfs_trans_next_item()
> 
> To prepare for different methods of committing items, convert the
> code to use xfs_trans_next_item() and factor the code into smaller,
> more digestible chunks.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>

Looks good,


Reviewed-by: Christoph Hellwig <hch@lst.de>

A few nits left over from the old code that might be worth fixing
while you're at it:

> -STATIC void	xfs_trans_chunk_committed(xfs_log_item_chunk_t *, xfs_lsn_t, int);

Once you start reoerding the functions, can we also move
xfs_trans_committed above it's user?

> +static void
> +xfs_trans_item_committed(
> +	xfs_log_item_t	*lip,
> +	xfs_lsn_t	commit_lsn,
> +	int		aborted)
>  {
> +	xfs_lsn_t	item_lsn;
> +	struct xfs_ail	*ailp;

Might be worth to switch to the struct types consistently and give
the variables another tab of indentation.

> +
> +	if (aborted)
> +		lip->li_flags |= XFS_LI_ABORTED;
>  
>  	/*
> +	 * Send in the ABORTED flag to the COMMITTED routine so that it knows
> +	 * whether the transaction was aborted or not.
>  	 */
> +	item_lsn = IOP_COMMITTED(lip, commit_lsn);

If we want to keep the comment it should be moved above the

	if (aborted)

abive.  But I'd just drop it.

> +xfs_trans_committed(
> +	xfs_trans_t	*tp,
> +	int		abortflag)
>  {
>  	xfs_log_item_desc_t	*lidp;
> +	xfs_log_item_chunk_t	*licp;
> +	xfs_log_item_chunk_t	*next_licp;
>  
> +	/*
> +	 * Call the transaction's completion callback if there
> +	 * is one.
> +	 */
> +	if (tp->t_callback != NULL) {
> +		tp->t_callback(tp, tp->t_callarg);
> +	}

	if (tp->t_callback)
		tp->t_callback(tp, tp->t_callarg);

> +	/* free the item chunks, ignoring the embedded chunk */
> +	licp = tp->t_items.lic_next;
> +	while (licp != NULL) {
> +		next_licp = licp->lic_next;
> +		ASSERT(xfs_lic_are_all_free(licp));
> +		kmem_free(licp);
> +		licp = next_licp;

	for (licp = tp->t_items.lic_next; licp != NULL; licp = next_licp) {
		next_licp = licp->lic_next;
		ASSERT(xfs_lic_are_all_free(licp));
		kmem_free(licp);
	}


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Re: [PATCH 8/9] xfs: introduce new internal log vector structure

[Christoph Hellwig]

On Sat, Mar 06, 2010 at 12:51:23PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> The current log IO vector structure is a flat array and not
> extensible. To make it possible to keep separate log IO vectors for
> individual log items, we need a method of chaining log IO vectors
> together.
> 
> Introduce a new log vector type that can be used to wrap the
> existing log IO vectors on use that internally to the log. This
> means that the existing external interface (xfs_log_write) does not
> change and hence no changes to the transaction commit code are
> required.
> 
> This initial use of the new log vectors does not use the chaining
> capability of the new log vector structure - it is not needed to
> implement the flat vector array the current transaction commit path
> creates.

Given that we don't need it yet I wonder if it would be a better idea
to postponed it to the start of the actual delayed logging series?

patch 9 would be nice to have before, but that might be a bit too much
rebase work.  Anyway, looking into a real review soon.

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Re: [PATCH 5/9] xfs: split out iclog writing from xfs_trans_commit()

[Dave Chinner]

On Sat, Mar 06, 2010 at 06:08:33AM -0500, Christoph Hellwig wrote:
> On Sat, Mar 06, 2010 at 12:51:20PM +1100, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> > 
> > Split the the part of xfs_trans_commit() that deals with writing the
> > transaction into the iclog into a separate function. This isolates the
> > physical commit process from the logical commit operation and makes
> > it easier to insert different transaction commit paths without affecting
> > the existing algorithm adversely.
> > 
> > Signed-off-by: Dave Chinner <dchinner@redhat.com>
> 
> Looks good, but some comments below:
> 
> > +        if (nvec > XFS_TRANS_LOGVEC_COUNT)
> > +                kmem_free(log_vector);
> 
> These two lines are indented with whitespaces instead of tabs.

Oops. Looks like I need to update my whitespace damage highlighting
rule...

> > +shut_us_down:
> > +	shutdown = XFS_FORCED_SHUTDOWN(mp) ? EIO : 0;
> > +	if (!(tp->t_flags & XFS_TRANS_DIRTY) || shutdown) {
> > +		xfs_trans_unreserve_and_mod_sb(tp);
> > +		/*
> 
> This whole area in _xfs_trans_commit is still a complete mess.

Yes, it is I didn't touch that part of the function, even though the
diff moves the whole thing about. Actually, the diff makes the
change look for more complex than it really is because it doesn't
keep it as three separate chunks of code that got moved....

> What about throwing the patch below in once you're rewriting it anyway?

I'll add it to the series and see how it goes.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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Re: [PATCH 6/9] xfs: update and factor xfs_trans_committed()

[Dave Chinner]

On Sat, Mar 06, 2010 at 06:24:58AM -0500, Christoph Hellwig wrote:
> On Sat, Mar 06, 2010 at 12:51:21PM +1100, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> > 
> > The function header to xfs-trans_committed has long had this
> > comment:
> > 
> >  * THIS SHOULD BE REWRITTEN TO USE xfs_trans_next_item()
> > 
> > To prepare for different methods of committing items, convert the
> > code to use xfs_trans_next_item() and factor the code into smaller,
> > more digestible chunks.
> > 
> > Signed-off-by: Dave Chinner <dchinner@redhat.com>
> 
> Looks good,
> 
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> 
> A few nits left over from the old code that might be worth fixing
> while you're at it:
> 
> > -STATIC void	xfs_trans_chunk_committed(xfs_log_item_chunk_t *, xfs_lsn_t, int);
> 
> Once you start reoerding the functions, can we also move
> xfs_trans_committed above it's user?

Will do.

> > +static void
> > +xfs_trans_item_committed(
> > +	xfs_log_item_t	*lip,
> > +	xfs_lsn_t	commit_lsn,
> > +	int		aborted)
> >  {
> > +	xfs_lsn_t	item_lsn;
> > +	struct xfs_ail	*ailp;
> 
> Might be worth to switch to the struct types consistently and give
> the variables another tab of indentation.

Fair call.

> 
> > +
> > +	if (aborted)
> > +		lip->li_flags |= XFS_LI_ABORTED;
> >  
> >  	/*
> > +	 * Send in the ABORTED flag to the COMMITTED routine so that it knows
> > +	 * whether the transaction was aborted or not.
> >  	 */
> > +	item_lsn = IOP_COMMITTED(lip, commit_lsn);
> 
> If we want to keep the comment it should be moved above the
> 
> 	if (aborted)
> 
> abive.  But I'd just drop it.

Ok, will do.

> 
> > +xfs_trans_committed(
> > +	xfs_trans_t	*tp,
> > +	int		abortflag)
> >  {
> >  	xfs_log_item_desc_t	*lidp;
> > +	xfs_log_item_chunk_t	*licp;
> > +	xfs_log_item_chunk_t	*next_licp;
> >  
> > +	/*
> > +	 * Call the transaction's completion callback if there
> > +	 * is one.
> > +	 */
> > +	if (tp->t_callback != NULL) {
> > +		tp->t_callback(tp, tp->t_callarg);
> > +	}
> 
> 	if (tp->t_callback)
> 		tp->t_callback(tp, tp->t_callarg);

Once again, that's code I didn't touch but the diff has moved about.
I'll clean up the entire function given what the diff is doing...

> > +	/* free the item chunks, ignoring the embedded chunk */
> > +	licp = tp->t_items.lic_next;
> > +	while (licp != NULL) {
> > +		next_licp = licp->lic_next;
> > +		ASSERT(xfs_lic_are_all_free(licp));
> > +		kmem_free(licp);
> > +		licp = next_licp;
> 
> 	for (licp = tp->t_items.lic_next; licp != NULL; licp = next_licp) {
> 		next_licp = licp->lic_next;
> 		ASSERT(xfs_lic_are_all_free(licp));
> 		kmem_free(licp);
> 	}

Yes, makes sense.

Cheers,

Dave.
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Re: [PATCH 8/9] xfs: introduce new internal log vector structure

[Dave Chinner]

On Sat, Mar 06, 2010 at 06:31:19AM -0500, Christoph Hellwig wrote:
> On Sat, Mar 06, 2010 at 12:51:23PM +1100, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> > 
> > The current log IO vector structure is a flat array and not
> > extensible. To make it possible to keep separate log IO vectors for
> > individual log items, we need a method of chaining log IO vectors
> > together.
> > 
> > Introduce a new log vector type that can be used to wrap the
> > existing log IO vectors on use that internally to the log. This
> > means that the existing external interface (xfs_log_write) does not
> > change and hence no changes to the transaction commit code are
> > required.
> > 
> > This initial use of the new log vectors does not use the chaining
> > capability of the new log vector structure - it is not needed to
> > implement the flat vector array the current transaction commit path
> > creates.
> 
> Given that we don't need it yet I wonder if it would be a better idea
> to postponed it to the start of the actual delayed logging series?

Yes, it could be. I wanted to get it out separate from the delayed
logging patches so I could concentrate on them separately. I put it
in this series because it's been unchanged for some time now and
doesn't appear to cause any problems at all.

> patch 9 would be nice to have before, but that might be a bit too much
> rebase work.  Anyway, looking into a real review soon.

Yeah, that's what I didn't want to do. The code as it stands in
these patches is actually tested with chained log vectors (the next
patch in the series contains all the delayed logging stuff which I
haven't split yet), so I didn't want to propose code for the dev tree
that I wasn't actually testing....

Cheers,

Dave.
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Re: [PATCH 8/9] xfs: introduce new internal log vector structure

[Christoph Hellwig]

On Sat, Mar 06, 2010 at 12:51:23PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> The current log IO vector structure is a flat array and not
> extensible. To make it possible to keep separate log IO vectors for
> individual log items, we need a method of chaining log IO vectors
> together.
> 
> Introduce a new log vector type that can be used to wrap the
> existing log IO vectors on use that internally to the log. This
> means that the existing external interface (xfs_log_write) does not
> change and hence no changes to the transaction commit code are
> required.
> 
> This initial use of the new log vectors does not use the chaining
> capability of the new log vector structure - it is not needed to
> implement the flat vector array the current transaction commit path
> creates.

Looks good to me,


Reviewed-by: Christoph Hellwig <hch@lst.de>

A few comments below:

> +			/* the data section must be 32 bit size aligned */
> +			struct {
> +			    __uint16_t magic;
> +			    __uint16_t pad1;
> +			    __uint32_t pad2; /* may as well make it 64 bits */
> +			} magic = {
> +				.magic = XLOG_UNMOUNT_TYPE,
> +			};
> +			struct xfs_log_iovec reg = {
> +				.i_addr = (void *)&magic,
> +				.i_len = sizeof(magic),
> +				.i_type = XLOG_REG_TYPE_UNMOUNT,
> +			};
> +			struct xfs_log_vec vec = {
> +				.lv_niovecs = 1,
> +			};
> +			/* sigh. c99 initialisers don't work on anon unions */
> +			vec.lv_iovecp = &reg;

I can't see an anonymous union involved anywhere here, and initializing
these normally works just fine (see patch below).

Index: xfs/fs/xfs/xfs_log.c
===================================================================
--- xfs.orig/fs/xfs/xfs_log.c	2010-03-06 16:40:35.817021839 +0100
+++ xfs/fs/xfs/xfs_log.c	2010-03-06 16:41:49.873004518 +0100
@@ -557,9 +557,8 @@ xfs_log_unmount_write(xfs_mount_t *mp)
 			};
 			struct xfs_log_vec vec = {
 				.lv_niovecs = 1,
+				.lv_iovecp = &reg,
 			};
-			/* sigh. c99 initialisers don't work on anon unions */
-			vec.lv_iovecp = &reg;
 
 			/* remove inited flag */
 			tic->t_flags = 0;
@@ -686,9 +685,8 @@ xfs_log_write(
 	int			error;
 	struct xfs_log_vec	vec = {
 		.lv_niovecs = nentries,
+		.lv_iovecp = reg,
 	};
-	/* sigh. c99 initialisers don't work on anon unions */
-	vec.lv_iovecp = reg;
 
 	if (XLOG_FORCED_SHUTDOWN(log))
 		return XFS_ERROR(EIO);
@@ -1201,9 +1199,8 @@ xlog_commit_record(
 	};
 	struct xfs_log_vec vec = {
 		.lv_niovecs = 1,
+		.lv_iovecp = &reg,
 	};
-	/* sigh. c99 initialisers don't work on anon unions */
-	vec.lv_iovecp = &reg;
 
 	ASSERT_ALWAYS(iclog);
 	error = xlog_write(log, &vec, ticket, commitlsnp, iclog,

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Re: [PATCH 9/9] xfs: factor xlog_write and make use of new log vector structure

[Christoph Hellwig]

On Sat, Mar 06, 2010 at 12:51:24PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> xlog_write is a mess that takes a lot of effort to understand. It is
> a mass of nested loops with 4 space indents to get it to fit in 80 columns
> and lots of funky variables that aren't obvious what they mean or do.
> 
> Break it down into understandable chunks, format them properly and propagate
> the new log vector structure into it to support chaining of log vectors.

This looks good to me, but I have a bit of a hard time to verify it.

As mention before I think this would be much better off as one
patch to split up xlog_write to go in before patch 8, and a separate
one to deal with the xfs_log_vecs, which could in fact be merged into
the existing patch 8, just to be reordered to be last - or even first
of the actual delayed logging series.

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Re: [PATCH 8/9] xfs: introduce new internal log vector structure

[Dave Chinner]

On Sat, Mar 06, 2010 at 10:46:10AM -0500, Christoph Hellwig wrote:
> On Sat, Mar 06, 2010 at 12:51:23PM +1100, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> > 
> > The current log IO vector structure is a flat array and not
> > extensible. To make it possible to keep separate log IO vectors for
> > individual log items, we need a method of chaining log IO vectors
> > together.
> > 
> > Introduce a new log vector type that can be used to wrap the
> > existing log IO vectors on use that internally to the log. This
> > means that the existing external interface (xfs_log_write) does not
> > change and hence no changes to the transaction commit code are
> > required.
> > 
> > This initial use of the new log vectors does not use the chaining
> > capability of the new log vector structure - it is not needed to
> > implement the flat vector array the current transaction commit path
> > creates.
> 
> Looks good to me,
> 
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> 
> A few comments below:
> 
> > +			/* the data section must be 32 bit size aligned */
> > +			struct {
> > +			    __uint16_t magic;
> > +			    __uint16_t pad1;
> > +			    __uint32_t pad2; /* may as well make it 64 bits */
> > +			} magic = {
> > +				.magic = XLOG_UNMOUNT_TYPE,
> > +			};
> > +			struct xfs_log_iovec reg = {
> > +				.i_addr = (void *)&magic,
> > +				.i_len = sizeof(magic),
> > +				.i_type = XLOG_REG_TYPE_UNMOUNT,
> > +			};
> > +			struct xfs_log_vec vec = {
> > +				.lv_niovecs = 1,
> > +			};
> > +			/* sigh. c99 initialisers don't work on anon unions */
> > +			vec.lv_iovecp = &reg;
> 
> I can't see an anonymous union involved anywhere here, and initializing
> these normally works just fine (see patch below).

Ah, I killed that union for this patch set - I was using embedded
arrays to cut down on memory allocations for the delayed logging so
there was a:

	union {
		struct xfs_log_iovec	*lv_iovecp;
		struct xfs_log_iovec	lv_iovec[0];
	};

in the structure. I decided that the union wasn't necessary for
these patches (and can be avoided entirely, anyway) but I forgot to
fix up the setup of the structure to remove those comments. I'll
update it as you've suggested.

Cheers,

Dave.
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Re: [PATCH 0/9] Log and transaction cleanups, factoring and bug fixes

[Christoph Hellwig]

With the whole series (and my posted cleanups) applied I get the
following XFSQA 113 failure (and a similar one before):

[ 2064.763171] Assertion failed: xfs_lic_are_all_free(licp), file: fs/xfs/xfs_trans.c, line: 1432
[ 2064.765993] ------------[ cut here ]------------
[ 2064.767449] kernel BUG at fs/xfs/support/debug.c:109!
[ 2064.768918] invalid opcode: 0000 [#1] SMP 
[ 2064.769847] last sysfs file: /sys/devices/virtio-pci/virtio1/block/vdb/removable
[ 2064.769847] Modules linked in:
[ 2064.769847] 
[ 2064.769847] Pid: 329, comm: xfslogd/0 Not tainted 2.6.33-xfs #477 /Bochs
[ 2064.769847] EIP: 0060:[<c04ede2e>] EFLAGS: 00010286 CPU: 0
[ 2064.769847] EIP is at assfail+0x1e/0x30
[ 2064.769847] EAX: 00000065 EBX: f5a91b40 ECX: f70c5040 EDX: 01704000
[ 2064.769847] ESI: 00000000 EDI: 00000000 EBP: f6b25e4c ESP: f6b25e3c
[ 2064.769847]  DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
[ 2064.769847] Process xfslogd/0 (pid: 329, ti=f6b24000 task=f70c5040 task.ti=f6b24000)
[ 2064.769847] Stack:
[ 2064.769847]  c0b74894 c0b2f5b6 c0b2f35a 00000598 f6b25e84 c04d4e66 000010d2 00000180
[ 2064.769847] <0> 00000180 000010d2 00001098 00000000 f4375574 f4375550 daaf3aa0 daaf3aa4
[ 2064.769847] <0> daaf3d3c 00000000 f6b25ee0 c04c53a2 00000046 f63273d4 f63273e4 00000292
[ 2064.769847] Call Trace:
[ 2064.769847]  [<c04d4e66>] ? xfs_trans_committed+0xe6/0x1b0
[ 2064.769847]  [<c04c53a2>] ? xlog_state_do_callback+0x282/0x3c0
[ 2064.769847]  [<c0158ad0>] ? __wake_up+0x40/0x50
[ 2064.769847]  [<c04c5974>] ? xlog_state_done_syncing+0xc4/0xe0
[ 2064.769847]  [<c04c5a81>] ? xlog_iodone+0xf1/0x160
[ 2064.769847]  [<c04e3f10>] ? xfs_buf_iodone_work+0x0/0xd0
[ 2064.769847]  [<c04e3f3f>] ? xfs_buf_iodone_work+0x2f/0xd0
[ 2064.769847]  [<c04e3f10>] ? xfs_buf_iodone_work+0x0/0xd0
[ 2064.769847]  [<c017a7c4>] ? worker_thread+0x154/0x270
[ 2064.769847]  [<c017a763>] ? worker_thread+0xf3/0x270
[ 2064.769847]  [<c017e1f0>] ? autoremove_wake_function+0x0/0x40
[ 2064.769847]  [<c017a670>] ? worker_thread+0x0/0x270
[ 2064.769847]  [<c017de3c>] ? kthread+0x6c/0x80
[ 2064.769847]  [<c017ddd0>] ? kthread+0x0/0x80
[ 2064.769847]  [<c012effa>] ? kernel_thread_helper+0x6/0x1c
[ 2064.769847] Code: 00 e8 e7 57 18 00 c9 c3 90 8d 74 26 00 55 89 e5 83 ec 10 89 4c 24 0c 89 54 24 08 89 44 24 04 c7 04 24 94 48 b7 c0 e8 35 a3 3f 00 <0f> 0b eb fe 8d b4 26 00 00 00 00 8d bc 27 00 00 00 00 55 89 e5 


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Re: [PATCH 0/9] Log and transaction cleanups, factoring and bug fixes

[Dave Chinner]

On Tue, Mar 09, 2010 at 06:39:19AM -0500, Christoph Hellwig wrote:
> With the whole series (and my posted cleanups) applied I get the
> following XFSQA 113 failure (and a similar one before):
> 
> [ 2064.763171] Assertion failed: xfs_lic_are_all_free(licp), file: fs/xfs/xfs_trans.c, line: 1432

Yeah, that's a bogus assert. I found it yesterday on test 113 ;)

The issue is that test 113 is the first QA test that is
semi-reliably creating a transaction with more than one chunk of log
item descriptors. The original assert was:

	ASSERT(!xfs_lic_are_all_free(licp));

before it called xfs_trans_chunk_committed() and ran the commit
processing on all the items in the chunk. It then freed the chunk.
This makes sense - there should be items in the chunk being freed.

I made the bogus assumption when cleaning up the code that after
committed processing on all the items that all the items in the
chunk would be marked as freed. However, nothing cleans up the log
item descriptors in the committed item processing, so the items in
the chunk are all still marked as used.

The fix is to either remove the assert or invert the condition....

Cheers,

Dave.
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Re: [PATCH 7/9] xfs: log ticket reservation underestimates the number of iclogs

[Dave Chinner]

Ping?

On Sat, Mar 06, 2010 at 12:51:22PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> When allocation a ticket for a transaction, the ticket is initialised with the
> worst case log space usage based on the number of bytes the transaction may
> consume. Part of this calculation is the number of log headers required for the
> iclog space used up by the transaction.
> 
> This calculation makes an undocumented assumption that if the transaction uses
> the log header space reservation on an iclog, then it consumes either the
> entire iclog or it completes. That is - the transaction that is first in an
> iclog is the transaction that the log header reservation is accounted to. If
> the transaction is larger than the iclog, then it will use the entire iclog
> itself. Document this assumption.
> 
> Further, the current calculation uses the rule that we can fit iclog_size bytes
> of transaction data into an iclog. This is in correct - the amount of space
> available in an iclog for transaction data is the size of the iclog minus the
> space used for log record headers. This means that the calculation is out by
> 512 bytes per 32k of log space the transaction can consume. This is rarely an
> issue because maximally sized transactions are extremely uncommon, and for 4k
> block size filesystems maximal transaction reservations are about 400kb. Hence
> the error in this case is less than the size of an iclog, so that makes it even
> harder to hit.
> 
> However, anyone using larger directory blocks (16k directory blocks push the
> maximum transaction size to approx. 900k on a 4k block size filesystem) or
> larger block size (e.g. 64k blocks push transactions to the 3-4MB size) could
> see the error grow to more than an iclog and at this point the transaction is
> guaranteed to get a reservation underrun and shutdown the filesystem.
> 
> Fix this by adjusting the calculation to calculate the correct number of iclogs
> required and account for them all up front.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
>  fs/xfs/xfs_log.c |   55 +++++++++++++++++++++++++++++++++++++++++------------
>  1 files changed, 42 insertions(+), 13 deletions(-)
> 
> diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
> index 1f26a97..7c6b0cd 100644
> --- a/fs/xfs/xfs_log.c
> +++ b/fs/xfs/xfs_log.c
> @@ -664,7 +664,10 @@ xfs_log_item_init(
>  /*
>   * Write region vectors to log.  The write happens using the space reservation
>   * of the ticket (tic).  It is not a requirement that all writes for a given
> - * transaction occur with one call to xfs_log_write().
> + * transaction occur with one call to xfs_log_write(). However, it is important
> + * to note that the transaction reservation code makes an assumption about the
> + * number of log headers a transaction requires that may be violated if you
> + * don't pass all the transaction vectors in one call....
>   */
>  int
>  xfs_log_write(
> @@ -3156,14 +3159,16 @@ xfs_log_ticket_get(
>   * Allocate and initialise a new log ticket.
>   */
>  STATIC xlog_ticket_t *
> -xlog_ticket_alloc(xlog_t		*log,
> -		int		unit_bytes,
> -		int		cnt,
> -		char		client,
> -		uint		xflags)
> +xlog_ticket_alloc(
> +	struct log	*log,
> +	int		unit_bytes,
> +	int		cnt,
> +	char		client,
> +	uint		xflags)
>  {
> -	xlog_ticket_t	*tic;
> +	struct xlog_ticket *tic;
>  	uint		num_headers;
> +	int		iclog_space;
>  
>  	tic = kmem_zone_zalloc(xfs_log_ticket_zone, KM_SLEEP|KM_MAYFAIL);
>  	if (!tic)
> @@ -3207,16 +3212,40 @@ xlog_ticket_alloc(xlog_t		*log,
>  	/* for start-rec */
>  	unit_bytes += sizeof(xlog_op_header_t);
>  
> -	/* for LR headers */
> -	num_headers = ((unit_bytes + log->l_iclog_size-1) >> log->l_iclog_size_log);
> +	/*
> +	 * for LR headers - the space for data in an iclog is the size minus
> +	 * the space used for the headers. If we use the iclog size, then we
> +	 * undercalculate the number of headers required.
> +	 *
> +	 * Furthermore - the addition of op headers for split-recs might
> +	 * increase the space required enough to require more log and op
> +	 * headers, so take that into account too.
> +	 *
> +	 * IMPORTANT: This reservation makes the assumption that if this
> +	 * transaction is the first in an iclog and hence has the LR headers
> +	 * accounted to it, then the remaining space in the iclog is
> +	 * exclusively for this transaction.  i.e. if the transaction is larger
> +	 * than the iclog, it will be the only thing in that iclog.
> +	 * Fundamentally, this means we must pass the entire log vector to
> +	 * xlog_write to guarantee this.
> +	 */
> +	iclog_space = log->l_iclog_size - log->l_iclog_hsize;
> +	num_headers = (unit_bytes + iclog_space - 1) / iclog_space;
> +
> +	/* for split-recs - ophdrs added when data split over LRs */
> +	unit_bytes += sizeof(xlog_op_header_t) * num_headers;
> +
> +	/* add extra header reservations if we overrun */
> +	while (!num_headers ||
> +	       ((unit_bytes + iclog_space - 1) / iclog_space) > num_headers) {
> +		unit_bytes += sizeof(xlog_op_header_t);
> +		num_headers++;
> +	}
>  	unit_bytes += log->l_iclog_hsize * num_headers;
>  
>  	/* for commit-rec LR header - note: padding will subsume the ophdr */
>  	unit_bytes += log->l_iclog_hsize;
>  
> -	/* for split-recs - ophdrs added when data split over LRs */
> -	unit_bytes += sizeof(xlog_op_header_t) * num_headers;
> -
>  	/* for roundoff padding for transaction data and one for commit record */
>  	if (xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
>  	    log->l_mp->m_sb.sb_logsunit > 1) {
> @@ -3238,7 +3267,7 @@ xlog_ticket_alloc(xlog_t		*log,
>  	tic->t_trans_type	= 0;
>  	if (xflags & XFS_LOG_PERM_RESERV)
>  		tic->t_flags |= XLOG_TIC_PERM_RESERV;
> -	sv_init(&(tic->t_wait), SV_DEFAULT, "logtick");
> +	sv_init(&tic->t_wait, SV_DEFAULT, "logtick");
>  
>  	xlog_tic_reset_res(tic);
>  
> -- 
> 1.6.5
> 
> _______________________________________________
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> xfs@oss.sgi.com
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> 

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[PATCH 5/9] xfs: split out iclog writing from xfs_trans_commit()

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

Split the the part of xfs_trans_commit() that deals with writing the
transaction into the iclog into a separate function. This isolates the
physical commit process from the logical commit operation and makes
it easier to insert different transaction commit paths without affecting
the existing algorithm adversely.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_trans.c |  387 +++++++++++++++++++++++++++-------------------------
 1 files changed, 199 insertions(+), 188 deletions(-)

diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index 6962f2b..e07b329 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -47,8 +47,6 @@
 
 
 STATIC void	xfs_trans_apply_sb_deltas(xfs_trans_t *);
-STATIC uint	xfs_trans_count_vecs(xfs_trans_t *);
-STATIC void	xfs_trans_fill_vecs(xfs_trans_t *, xfs_log_iovec_t *);
 STATIC void	xfs_trans_uncommit(xfs_trans_t *, uint);
 STATIC void	xfs_trans_committed(xfs_trans_t *, int);
 STATIC void	xfs_trans_chunk_committed(xfs_log_item_chunk_t *, xfs_lsn_t, int);
@@ -764,94 +762,126 @@ xfs_trans_unreserve_and_mod_sb(
 	}
 }
 
-
 /*
- * xfs_trans_commit
- *
- * Commit the given transaction to the log a/synchronously.
- *
- * XFS disk error handling mechanism is not based on a typical
- * transaction abort mechanism. Logically after the filesystem
- * gets marked 'SHUTDOWN', we can't let any new transactions
- * be durable - ie. committed to disk - because some metadata might
- * be inconsistent. In such cases, this returns an error, and the
- * caller may assume that all locked objects joined to the transaction
- * have already been unlocked as if the commit had succeeded.
- * Do not reference the transaction structure after this call.
+ * Total up the number of log iovecs needed to commit this
+ * transaction.  The transaction itself needs one for the
+ * transaction header.  Ask each dirty item in turn how many
+ * it needs to get the total.
  */
- /*ARGSUSED*/
-int
-_xfs_trans_commit(
-	xfs_trans_t	*tp,
-	uint		flags,
-	int		*log_flushed)
+static uint
+xfs_trans_count_vecs(
+	xfs_trans_t	*tp)
 {
-	xfs_log_iovec_t		*log_vector;
-	int			nvec;
-	xfs_mount_t		*mp;
-	xfs_lsn_t		commit_lsn;
-	/* REFERENCED */
-	int			error;
-	int			log_flags;
-	int			sync;
-#define	XFS_TRANS_LOGVEC_COUNT	16
-	xfs_log_iovec_t		log_vector_fast[XFS_TRANS_LOGVEC_COUNT];
-	struct xlog_in_core	*commit_iclog;
-	int			shutdown;
+	int			nvecs;
+	xfs_log_item_desc_t	*lidp;
 
-	commit_lsn = -1;
+	nvecs = 1;
+	lidp = xfs_trans_first_item(tp);
+	ASSERT(lidp != NULL);
 
-	/*
-	 * Determine whether this commit is releasing a permanent
-	 * log reservation or not.
+	/* In the non-debug case we need to start bailing out if we
+	 * didn't find a log_item here, return zero and let trans_commit
+	 * deal with it.
 	 */
-	if (flags & XFS_TRANS_RELEASE_LOG_RES) {
-		ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
-		log_flags = XFS_LOG_REL_PERM_RESERV;
-	} else {
-		log_flags = 0;
+	if (lidp == NULL)
+		return 0;
+
+	while (lidp != NULL) {
+		/*
+		 * Skip items which aren't dirty in this transaction.
+		 */
+		if (!(lidp->lid_flags & XFS_LID_DIRTY)) {
+			lidp = xfs_trans_next_item(tp, lidp);
+			continue;
+		}
+		lidp->lid_size = IOP_SIZE(lidp->lid_item);
+		nvecs += lidp->lid_size;
+		lidp = xfs_trans_next_item(tp, lidp);
 	}
-	mp = tp->t_mountp;
+
+	return nvecs;
+}
+
+/*
+ * Fill in the vector with pointers to data to be logged
+ * by this transaction.  The transaction header takes
+ * the first vector, and then each dirty item takes the
+ * number of vectors it indicated it needed in xfs_trans_count_vecs().
+ *
+ * As each item fills in the entries it needs, also pin the item
+ * so that it cannot be flushed out until the log write completes.
+ */
+static void
+xfs_trans_fill_vecs(
+	struct xfs_trans	*tp,
+	struct xfs_log_iovec	*log_vector)
+{
+	xfs_log_item_desc_t	*lidp;
+	struct xfs_log_iovec	*vecp;
+	uint			nitems;
 
 	/*
-	 * If there is nothing to be logged by the transaction,
-	 * then unlock all of the items associated with the
-	 * transaction and free the transaction structure.
-	 * Also make sure to return any reserved blocks to
-	 * the free pool.
+	 * Skip over the entry for the transaction header, we'll
+	 * fill that in at the end.
 	 */
-shut_us_down:
-	shutdown = XFS_FORCED_SHUTDOWN(mp) ? EIO : 0;
-	if (!(tp->t_flags & XFS_TRANS_DIRTY) || shutdown) {
-		xfs_trans_unreserve_and_mod_sb(tp);
+	vecp = log_vector + 1;
+
+	nitems = 0;
+	lidp = xfs_trans_first_item(tp);
+	ASSERT(lidp);
+	while (lidp) {
+		/* Skip items which aren't dirty in this transaction. */
+		if (!(lidp->lid_flags & XFS_LID_DIRTY)) {
+			lidp = xfs_trans_next_item(tp, lidp);
+			continue;
+		}
+
 		/*
-		 * It is indeed possible for the transaction to be
-		 * not dirty but the dqinfo portion to be. All that
-		 * means is that we have some (non-persistent) quota
-		 * reservations that need to be unreserved.
+		 * The item may be marked dirty but not log anything.  This can
+		 * be used to get called when a transaction is committed.
 		 */
-		xfs_trans_unreserve_and_mod_dquots(tp);
-		if (tp->t_ticket) {
-			commit_lsn = xfs_log_done(mp, tp->t_ticket,
-							NULL, log_flags);
-			if (commit_lsn == -1 && !shutdown)
-				shutdown = XFS_ERROR(EIO);
-		}
-		current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
-		xfs_trans_free_items(tp, shutdown? XFS_TRANS_ABORT : 0);
-		xfs_trans_free_busy(tp);
-		xfs_trans_free(tp);
-		XFS_STATS_INC(xs_trans_empty);
-		return (shutdown);
+		if (lidp->lid_size)
+			nitems++;
+		IOP_FORMAT(lidp->lid_item, vecp);
+		vecp += lidp->lid_size;
+		IOP_PIN(lidp->lid_item);
+		lidp = xfs_trans_next_item(tp, lidp);
 	}
-	ASSERT(tp->t_ticket != NULL);
 
 	/*
-	 * If we need to update the superblock, then do it now.
+	 * Now that we've counted the number of items in this transaction, fill
+	 * in the transaction header. Note that the transaction header does not
+	 * have a log item.
 	 */
-	if (tp->t_flags & XFS_TRANS_SB_DIRTY)
-		xfs_trans_apply_sb_deltas(tp);
-	xfs_trans_apply_dquot_deltas(tp);
+	tp->t_header.th_magic = XFS_TRANS_HEADER_MAGIC;
+	tp->t_header.th_type = tp->t_type;
+	tp->t_header.th_num_items = nitems;
+	log_vector->i_addr = (xfs_caddr_t)&tp->t_header;
+	log_vector->i_len = sizeof(xfs_trans_header_t);
+	log_vector->i_type = XLOG_REG_TYPE_TRANSHDR;
+}
+
+/*
+ * Format the transaction direct to the iclog. This isolates the physical
+ * transaction commit operation from the logical operation and hence allows
+ * other methods to be introduced without affecting the existing commit path.
+ */
+static int
+xfs_trans_commit_iclog(
+	struct xfs_mount	*mp,
+	struct xfs_trans	*tp,
+	xfs_lsn_t		*commit_lsn,
+	int			flags)
+{
+	int			shutdown;
+	int			error;
+	int			log_flags = 0;
+	struct xlog_in_core	*commit_iclog;
+#define XFS_TRANS_LOGVEC_COUNT  16
+	struct xfs_log_iovec	log_vector_fast[XFS_TRANS_LOGVEC_COUNT];
+	struct xfs_log_iovec	*log_vector;
+	uint			nvec;
+
 
 	/*
 	 * Ask each log item how many log_vector entries it will
@@ -861,8 +891,7 @@ shut_us_down:
 	 */
 	nvec = xfs_trans_count_vecs(tp);
 	if (nvec == 0) {
-		xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
-		goto shut_us_down;
+		return ENOMEM;	/* triggers a shutdown! */
 	} else if (nvec <= XFS_TRANS_LOGVEC_COUNT) {
 		log_vector = log_vector_fast;
 	} else {
@@ -877,6 +906,9 @@ shut_us_down:
 	 */
 	xfs_trans_fill_vecs(tp, log_vector);
 
+	if (flags & XFS_TRANS_RELEASE_LOG_RES)
+		log_flags = XFS_LOG_REL_PERM_RESERV;
+
 	error = xfs_log_write(mp, log_vector, nvec, tp->t_ticket, &(tp->t_lsn));
 
 	/*
@@ -884,18 +916,17 @@ shut_us_down:
 	 * at any time after this call.  However, all the items associated
 	 * with the transaction are still locked and pinned in memory.
 	 */
-	commit_lsn = xfs_log_done(mp, tp->t_ticket, &commit_iclog, log_flags);
+	*commit_lsn = xfs_log_done(mp, tp->t_ticket, &commit_iclog, log_flags);
 
-	tp->t_commit_lsn = commit_lsn;
-	if (nvec > XFS_TRANS_LOGVEC_COUNT) {
+	tp->t_commit_lsn = *commit_lsn;
+	if (nvec > XFS_TRANS_LOGVEC_COUNT)
 		kmem_free(log_vector);
-	}
 
 	/*
 	 * If we got a log write error. Unpin the logitems that we
 	 * had pinned, clean up, free trans structure, and return error.
 	 */
-	if (error || commit_lsn == -1) {
+	if (error || *commit_lsn == -1) {
 		current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
 		xfs_trans_uncommit(tp, flags|XFS_TRANS_ABORT);
 		return XFS_ERROR(EIO);
@@ -909,8 +940,6 @@ shut_us_down:
 	 */
 	xfs_trans_unreserve_and_mod_sb(tp);
 
-	sync = tp->t_flags & XFS_TRANS_SYNC;
-
 	/*
 	 * Tell the LM to call the transaction completion routine
 	 * when the log write with LSN commit_lsn completes (e.g.
@@ -953,7 +982,7 @@ shut_us_down:
 	 * the commit lsn of this transaction for dependency tracking
 	 * purposes.
 	 */
-	xfs_trans_unlock_items(tp, commit_lsn);
+	xfs_trans_unlock_items(tp, *commit_lsn);
 
 	/*
 	 * If we detected a log error earlier, finish committing
@@ -973,7 +1002,92 @@ shut_us_down:
 	 * and the items are released we can finally allow the iclog to
 	 * go to disk.
 	 */
-	error = xfs_log_release_iclog(mp, commit_iclog);
+	return xfs_log_release_iclog(mp, commit_iclog);
+}
+
+
+/*
+ * xfs_trans_commit
+ *
+ * Commit the given transaction to the log a/synchronously.
+ *
+ * XFS disk error handling mechanism is not based on a typical
+ * transaction abort mechanism. Logically after the filesystem
+ * gets marked 'SHUTDOWN', we can't let any new transactions
+ * be durable - ie. committed to disk - because some metadata might
+ * be inconsistent. In such cases, this returns an error, and the
+ * caller may assume that all locked objects joined to the transaction
+ * have already been unlocked as if the commit had succeeded.
+ * Do not reference the transaction structure after this call.
+ */
+ /*ARGSUSED*/
+int
+_xfs_trans_commit(
+	xfs_trans_t	*tp,
+	uint		flags,
+	int		*log_flushed)
+{
+	xfs_mount_t		*mp = tp->t_mountp;
+	xfs_lsn_t		commit_lsn = -1;
+	int			error;
+	int			log_flags = 0;
+	int			sync = tp->t_flags & XFS_TRANS_SYNC;
+	int			shutdown;
+
+	/*
+	 * Determine whether this commit is releasing a permanent
+	 * log reservation or not.
+	 */
+	if (flags & XFS_TRANS_RELEASE_LOG_RES) {
+		ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
+		log_flags = XFS_LOG_REL_PERM_RESERV;
+	}
+
+	/*
+	 * If there is nothing to be logged by the transaction,
+	 * then unlock all of the items associated with the
+	 * transaction and free the transaction structure.
+	 * Also make sure to return any reserved blocks to
+	 * the free pool.
+	 */
+shut_us_down:
+	shutdown = XFS_FORCED_SHUTDOWN(mp) ? EIO : 0;
+	if (!(tp->t_flags & XFS_TRANS_DIRTY) || shutdown) {
+		xfs_trans_unreserve_and_mod_sb(tp);
+		/*
+		 * It is indeed possible for the transaction to be
+		 * not dirty but the dqinfo portion to be. All that
+		 * means is that we have some (non-persistent) quota
+		 * reservations that need to be unreserved.
+		 */
+		xfs_trans_unreserve_and_mod_dquots(tp);
+		if (tp->t_ticket) {
+			commit_lsn = xfs_log_done(mp, tp->t_ticket,
+							NULL, log_flags);
+			if (commit_lsn == -1 && !shutdown)
+				shutdown = XFS_ERROR(EIO);
+		}
+		current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
+		xfs_trans_free_items(tp, shutdown? XFS_TRANS_ABORT : 0);
+		xfs_trans_free_busy(tp);
+		xfs_trans_free(tp);
+		XFS_STATS_INC(xs_trans_empty);
+		return (shutdown);
+	}
+	ASSERT(tp->t_ticket != NULL);
+
+	/*
+	 * If we need to update the superblock, then do it now.
+	 */
+	if (tp->t_flags & XFS_TRANS_SB_DIRTY)
+		xfs_trans_apply_sb_deltas(tp);
+	xfs_trans_apply_dquot_deltas(tp);
+
+	error = xfs_trans_commit_iclog(mp, tp, &commit_lsn, flags);
+	if (error == ENOMEM) {
+		xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
+		goto shut_us_down;
+	}
 
 	/*
 	 * If the transaction needs to be synchronous, then force the
@@ -992,47 +1106,6 @@ shut_us_down:
 	return (error);
 }
 
-
-/*
- * Total up the number of log iovecs needed to commit this
- * transaction.  The transaction itself needs one for the
- * transaction header.  Ask each dirty item in turn how many
- * it needs to get the total.
- */
-STATIC uint
-xfs_trans_count_vecs(
-	xfs_trans_t	*tp)
-{
-	int			nvecs;
-	xfs_log_item_desc_t	*lidp;
-
-	nvecs = 1;
-	lidp = xfs_trans_first_item(tp);
-	ASSERT(lidp != NULL);
-
-	/* In the non-debug case we need to start bailing out if we
-	 * didn't find a log_item here, return zero and let trans_commit
-	 * deal with it.
-	 */
-	if (lidp == NULL)
-		return 0;
-
-	while (lidp != NULL) {
-		/*
-		 * Skip items which aren't dirty in this transaction.
-		 */
-		if (!(lidp->lid_flags & XFS_LID_DIRTY)) {
-			lidp = xfs_trans_next_item(tp, lidp);
-			continue;
-		}
-		lidp->lid_size = IOP_SIZE(lidp->lid_item);
-		nvecs += lidp->lid_size;
-		lidp = xfs_trans_next_item(tp, lidp);
-	}
-
-	return nvecs;
-}
-
 /*
  * Called from the trans_commit code when we notice that
  * the filesystem is in the middle of a forced shutdown.
@@ -1063,68 +1136,6 @@ xfs_trans_uncommit(
 }
 
 /*
- * Fill in the vector with pointers to data to be logged
- * by this transaction.  The transaction header takes
- * the first vector, and then each dirty item takes the
- * number of vectors it indicated it needed in xfs_trans_count_vecs().
- *
- * As each item fills in the entries it needs, also pin the item
- * so that it cannot be flushed out until the log write completes.
- */
-STATIC void
-xfs_trans_fill_vecs(
-	xfs_trans_t		*tp,
-	xfs_log_iovec_t		*log_vector)
-{
-	xfs_log_item_desc_t	*lidp;
-	xfs_log_iovec_t		*vecp;
-	uint			nitems;
-
-	/*
-	 * Skip over the entry for the transaction header, we'll
-	 * fill that in at the end.
-	 */
-	vecp = log_vector + 1;		/* pointer arithmetic */
-
-	nitems = 0;
-	lidp = xfs_trans_first_item(tp);
-	ASSERT(lidp != NULL);
-	while (lidp != NULL) {
-		/*
-		 * Skip items which aren't dirty in this transaction.
-		 */
-		if (!(lidp->lid_flags & XFS_LID_DIRTY)) {
-			lidp = xfs_trans_next_item(tp, lidp);
-			continue;
-		}
-		/*
-		 * The item may be marked dirty but not log anything.
-		 * This can be used to get called when a transaction
-		 * is committed.
-		 */
-		if (lidp->lid_size) {
-			nitems++;
-		}
-		IOP_FORMAT(lidp->lid_item, vecp);
-		vecp += lidp->lid_size;		/* pointer arithmetic */
-		IOP_PIN(lidp->lid_item);
-		lidp = xfs_trans_next_item(tp, lidp);
-	}
-
-	/*
-	 * Now that we've counted the number of items in this
-	 * transaction, fill in the transaction header.
-	 */
-	tp->t_header.th_magic = XFS_TRANS_HEADER_MAGIC;
-	tp->t_header.th_type = tp->t_type;
-	tp->t_header.th_num_items = nitems;
-	log_vector->i_addr = (xfs_caddr_t)&tp->t_header;
-	log_vector->i_len = sizeof(xfs_trans_header_t);
-	log_vector->i_type = XLOG_REG_TYPE_TRANSHDR;
-}
-
-
-/*
  * Unlock all of the transaction's items and free the transaction.
  * The transaction must not have modified any of its items, because
  * there is no way to restore them to their previous state.
-- 
1.6.5

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