1 files changed, 190 insertions, 181 deletions

diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c
index 02b9cf3..cfe9797 100644
--- a/fs/xfs/xfs_log_cil.c
+++ b/fs/xfs/xfs_log_cil.c
@@ -80,6 +80,83 @@ xlog_cil_init_post_recovery(
 								log->l_curr_block);
 }
 
+STATIC int
+xlog_cil_lv_item_format(
+	struct xfs_log_item	*lip,
+	struct xfs_log_vec	*lv)
+{
+	int	index;
+	char	*ptr;
+
+	/* format new vectors into array */
+	lip->li_ops->iop_format(lip, lv->lv_iovecp);
+
+	/* copy data into existing array */
+	ptr = lv->lv_buf;
+	for (index = 0; index < lv->lv_niovecs; index++) {
+		struct xfs_log_iovec *vec = &lv->lv_iovecp[index];
+
+		memcpy(ptr, vec->i_addr, vec->i_len);
+		vec->i_addr = ptr;
+		ptr += vec->i_len;
+	}
+
+	/*
+	 * some size calculations for log vectors over-estimate, so the caller
+	 * doesn't know the amount of space actually used by the item. Return
+	 * the byte count to the caller so they can check and store it
+	 * appropriately.
+	 */
+	return ptr - lv->lv_buf;
+}
+
+/*
+ * Prepare the log item for insertion into the CIL. Calculate the difference in
+ * log space and vectors it will consume, and if it is a new item pin it as
+ * well.
+ */
+STATIC void
+xfs_cil_prepare_item(
+	struct xlog		*log,
+	struct xfs_log_vec	*lv,
+	struct xfs_log_vec	*old_lv,
+	int			*diff_len,
+	int			*diff_iovecs)
+{
+	/* Account for the new LV being passed in */
+	if (lv->lv_buf_len != XFS_LOG_VEC_ORDERED) {
+		*diff_len += lv->lv_buf_len;
+		*diff_iovecs += lv->lv_niovecs;
+	}
+
+	/*
+	 * If there is no old LV, this is the first time we've seen the item in
+	 * this CIL context and so we need to pin it. If we are replacing the
+	 * old_lv, then remove the space it accounts for and free it.
+	 */
+	if (!old_lv)
+		lv->lv_item->li_ops->iop_pin(lv->lv_item);
+	else if (old_lv != lv) {
+		ASSERT(lv->lv_buf_len != XFS_LOG_VEC_ORDERED);
+
+		*diff_len -= old_lv->lv_buf_len;
+		*diff_iovecs -= old_lv->lv_niovecs;
+		kmem_free(old_lv);
+	}
+
+	/* attach new log vector to log item */
+	lv->lv_item->li_lv = lv;
+
+	/*
+	 * If this is the first time the item is being committed to the
+	 * CIL, store the sequence number on the log item so we can
+	 * tell in future commits whether this is the first checkpoint
+	 * the item is being committed into.
+	 */
+	if (!lv->lv_item->li_seq)
+		lv->lv_item->li_seq = log->l_cilp->xc_ctx->sequence;
+}
+
 /*
  * Format log item into a flat buffers
  *
@@ -106,35 +183,39 @@ xlog_cil_init_post_recovery(
  * format the regions into the iclog as though they are being formatted
  * directly out of the objects themselves.
  */
-static struct xfs_log_vec *
-xlog_cil_prepare_log_vecs(
-	struct xfs_trans	*tp)
+static void
+xlog_cil_insert_format_items(
+	struct xlog		*log,
+	struct xfs_trans	*tp,
+	int			*diff_len,
+	int			*diff_iovecs)
 {
 	struct xfs_log_item_desc *lidp;
-	struct xfs_log_vec	*lv = NULL;
-	struct xfs_log_vec	*ret_lv = NULL;
 
 
 	/* Bail out if we didn't find a log item.  */
 	if (list_empty(&tp->t_items)) {
 		ASSERT(0);
-		return NULL;
+		return;
 	}
 
 	list_for_each_entry(lidp, &tp->t_items, lid_trans) {
-		struct xfs_log_vec *new_lv;
-		void	*ptr;
-		int	index;
-		int	len = 0;
-		uint	niovecs;
+		struct xfs_log_item *lip = lidp->lid_item;
+		struct xfs_log_vec *lv;
+		struct xfs_log_vec *old_lv;
+		int	niovecs = 0;
+		int	nbytes = 0;
+		int	buf_size;
 		bool	ordered = false;
 
 		/* Skip items which aren't dirty in this transaction. */
 		if (!(lidp->lid_flags & XFS_LID_DIRTY))
 			continue;
 
+		/* get number of vecs and size of data to be stored */
+		lip->li_ops->iop_size(lip, &niovecs, &nbytes);
+
 		/* Skip items that do not have any vectors for writing */
-		niovecs = IOP_SIZE(lidp->lid_item);
 		if (!niovecs)
 			continue;
 
@@ -146,109 +227,63 @@ xlog_cil_prepare_log_vecs(
 		if (niovecs == XFS_LOG_VEC_ORDERED) {
 			ordered = true;
 			niovecs = 0;
+			nbytes = 0;
 		}
 
-		new_lv = kmem_zalloc(sizeof(*new_lv) +
-				niovecs * sizeof(struct xfs_log_iovec),
-				KM_SLEEP|KM_NOFS);
-
-		new_lv->lv_item = lidp->lid_item;
-		new_lv->lv_niovecs = niovecs;
-		if (ordered) {
-			/* track as an ordered logvec */
-			new_lv->lv_buf_len = XFS_LOG_VEC_ORDERED;
-			goto next;
-		}
-
-		/* The allocated iovec region lies beyond the log vector. */
-		new_lv->lv_iovecp = (struct xfs_log_iovec *)&new_lv[1];
+		/* grab the old item if it exists for reservation accounting */
+		old_lv = lip->li_lv;
 
-		/* build the vector array and calculate it's length */
-		IOP_FORMAT(new_lv->lv_item, new_lv->lv_iovecp);
-		for (index = 0; index < new_lv->lv_niovecs; index++)
-			len += new_lv->lv_iovecp[index].i_len;
+		/* calc buffer size */
+		buf_size = sizeof(struct xfs_log_vec) + nbytes +
+				niovecs * sizeof(struct xfs_log_iovec);
 
-		new_lv->lv_buf_len = len;
-		new_lv->lv_buf = kmem_alloc(new_lv->lv_buf_len,
-				KM_SLEEP|KM_NOFS);
-		ptr = new_lv->lv_buf;
+		/* compare to existing item size */
+		if (lip->li_lv && buf_size <= lip->li_lv->lv_size) {
+			/* same or smaller, optimise common overwrite case */
+			lv = lip->li_lv;
+			lv->lv_next = NULL;
 
-		for (index = 0; index < new_lv->lv_niovecs; index++) {
-			struct xfs_log_iovec *vec = &new_lv->lv_iovecp[index];
+			if (ordered)
+				goto insert;
 
-			memcpy(ptr, vec->i_addr, vec->i_len);
-			vec->i_addr = ptr;
-			ptr += vec->i_len;
-		}
-		ASSERT(ptr == new_lv->lv_buf + new_lv->lv_buf_len);
-
-next:
-		if (!ret_lv)
-			ret_lv = new_lv;
-		else
-			lv->lv_next = new_lv;
-		lv = new_lv;
-	}
-
-	return ret_lv;
-}
-
-/*
- * Prepare the log item for insertion into the CIL. Calculate the difference in
- * log space and vectors it will consume, and if it is a new item pin it as
- * well.
- */
-STATIC void
-xfs_cil_prepare_item(
-	struct xlog		*log,
-	struct xfs_log_vec	*lv,
-	int			*len,
-	int			*diff_iovecs)
-{
-	struct xfs_log_vec	*old = lv->lv_item->li_lv;
+			/*
+			 * set the item up as though it is a new insertion so
+			 * that the space reservation accounting is correct.
+			 */
+			*diff_iovecs -= lv->lv_niovecs;
+			*diff_len -= lv->lv_buf_len;
 
-	if (old) {
-		/* existing lv on log item, space used is a delta */
-		ASSERT((old->lv_buf && old->lv_buf_len && old->lv_niovecs) ||
-			old->lv_buf_len == XFS_LOG_VEC_ORDERED);
+			/* Ensure the lv is set up according to ->iop_size */
+			lv->lv_niovecs = niovecs;
+			lv->lv_buf = (char *)lv + buf_size - nbytes;
 
-		/*
-		 * If the new item is ordered, keep the old one that is already
-		 * tracking dirty or ordered regions
-		 */
-		if (lv->lv_buf_len == XFS_LOG_VEC_ORDERED) {
-			ASSERT(!lv->lv_buf);
-			kmem_free(lv);
-			return;
+			lv->lv_buf_len = xlog_cil_lv_item_format(lip, lv);
+			goto insert;
 		}
 
-		*len += lv->lv_buf_len - old->lv_buf_len;
-		*diff_iovecs += lv->lv_niovecs - old->lv_niovecs;
-		kmem_free(old->lv_buf);
-		kmem_free(old);
-	} else {
-		/* new lv, must pin the log item */
-		ASSERT(!lv->lv_item->li_lv);
-
-		if (lv->lv_buf_len != XFS_LOG_VEC_ORDERED) {
-			*len += lv->lv_buf_len;
-			*diff_iovecs += lv->lv_niovecs;
+		/* allocate new data chunk */
+		lv = kmem_zalloc(buf_size, KM_SLEEP|KM_NOFS);
+		lv->lv_item = lip;
+		lv->lv_size = buf_size;
+		lv->lv_niovecs = niovecs;
+		if (ordered) {
+			/* track as an ordered logvec */
+			ASSERT(lip->li_lv == NULL);
+			lv->lv_buf_len = XFS_LOG_VEC_ORDERED;
+			goto insert;
 		}
-		IOP_PIN(lv->lv_item);
 
-	}
+		/* The allocated iovec region lies beyond the log vector. */
+		lv->lv_iovecp = (struct xfs_log_iovec *)&lv[1];
 
-	/* attach new log vector to log item */
-	lv->lv_item->li_lv = lv;
+		/* The allocated data region lies beyond the iovec region */
+		lv->lv_buf = (char *)lv + buf_size - nbytes;
 
-	/*
-	 * If this is the first time the item is being committed to the
-	 * CIL, store the sequence number on the log item so we can
-	 * tell in future commits whether this is the first checkpoint
-	 * the item is being committed into.
-	 */
-	if (!lv->lv_item->li_seq)
-		lv->lv_item->li_seq = log->l_cilp->xc_ctx->sequence;
+		lv->lv_buf_len = xlog_cil_lv_item_format(lip, lv);
+insert:
+		ASSERT(lv->lv_buf_len <= nbytes);
+		xfs_cil_prepare_item(log, lv, old_lv, diff_len, diff_iovecs);
+	}
 }
 
 /*
@@ -261,53 +296,47 @@ xfs_cil_prepare_item(
 static void
 xlog_cil_insert_items(
 	struct xlog		*log,
-	struct xfs_log_vec	*log_vector,
-	struct xlog_ticket	*ticket)
+	struct xfs_trans	*tp)
 {
 	struct xfs_cil		*cil = log->l_cilp;
 	struct xfs_cil_ctx	*ctx = cil->xc_ctx;
-	struct xfs_log_vec	*lv;
+	struct xfs_log_item_desc *lidp;
 	int			len = 0;
 	int			diff_iovecs = 0;
 	int			iclog_space;
 
-	ASSERT(log_vector);
+	ASSERT(tp);
 
 	/*
-	 * Do all the accounting aggregation and switching of log vectors
-	 * around in a separate loop to the insertion of items into the CIL.
-	 * Then we can do a separate loop to update the CIL within a single
-	 * lock/unlock pair. This reduces the number of round trips on the CIL
-	 * lock from O(nr_logvectors) to O(1) and greatly reduces the overall
-	 * hold time for the transaction commit.
-	 *
-	 * If this is the first time the item is being placed into the CIL in
-	 * this context, pin it so it can't be written to disk until the CIL is
-	 * flushed to the iclog and the iclog written to disk.
-	 *
 	 * We can do this safely because the context can't checkpoint until we
 	 * are done so it doesn't matter exactly how we update the CIL.
 	 */
+	xlog_cil_insert_format_items(log, tp, &len, &diff_iovecs);
+
+	/*
+	 * Now (re-)position everything modified at the tail of the CIL.
+	 * We do this here so we only need to take the CIL lock once during
+	 * the transaction commit.
+	 */
 	spin_lock(&cil->xc_cil_lock);
-	for (lv = log_vector; lv; ) {
-		struct xfs_log_vec *next = lv->lv_next;
+	list_for_each_entry(lidp, &tp->t_items, lid_trans) {
+		struct xfs_log_item	*lip = lidp->lid_item;
 
-		ASSERT(lv->lv_item->li_lv || list_empty(&lv->lv_item->li_cil));
-		lv->lv_next = NULL;
+		/* Skip items which aren't dirty in this transaction. */
+		if (!(lidp->lid_flags & XFS_LID_DIRTY))
+			continue;
 
-		/*
-		 * xfs_cil_prepare_item() may free the lv, so move the item on
-		 * the CIL first.
-		 */
-		list_move_tail(&lv->lv_item->li_cil, &cil->xc_cil);
-		xfs_cil_prepare_item(log, lv, &len, &diff_iovecs);
-		lv = next;
+		list_move_tail(&lip->li_cil, &cil->xc_cil);
 	}
 
 	/* account for space used by new iovec headers  */
 	len += diff_iovecs * sizeof(xlog_op_header_t);
 	ctx->nvecs += diff_iovecs;
 
+	/* attach the transaction to the CIL if it has any busy extents */
+	if (!list_empty(&tp->t_busy))
+		list_splice_init(&tp->t_busy, &ctx->busy_extents);
+
 	/*
 	 * Now transfer enough transaction reservation to the context ticket
 	 * for the checkpoint. The context ticket is special - the unit
@@ -316,10 +345,8 @@ xlog_cil_insert_items(
 	 * during the transaction commit.
 	 */
 	if (ctx->ticket->t_curr_res == 0) {
-		/* first commit in checkpoint, steal the header reservation */
-		ASSERT(ticket->t_curr_res >= ctx->ticket->t_unit_res + len);
 		ctx->ticket->t_curr_res = ctx->ticket->t_unit_res;
-		ticket->t_curr_res -= ctx->ticket->t_unit_res;
+		tp->t_ticket->t_curr_res -= ctx->ticket->t_unit_res;
 	}
 
 	/* do we need space for more log record headers? */
@@ -333,10 +360,10 @@ xlog_cil_insert_items(
 		hdrs *= log->l_iclog_hsize + sizeof(struct xlog_op_header);
 		ctx->ticket->t_unit_res += hdrs;
 		ctx->ticket->t_curr_res += hdrs;
-		ticket->t_curr_res -= hdrs;
-		ASSERT(ticket->t_curr_res >= len);
+		tp->t_ticket->t_curr_res -= hdrs;
+		ASSERT(tp->t_ticket->t_curr_res >= len);
 	}
-	ticket->t_curr_res -= len;
+	tp->t_ticket->t_curr_res -= len;
 	ctx->space_used += len;
 
 	spin_unlock(&cil->xc_cil_lock);
@@ -350,7 +377,6 @@ xlog_cil_free_logvec(
 
 	for (lv = log_vector; lv; ) {
 		struct xfs_log_vec *next = lv->lv_next;
-		kmem_free(lv->lv_buf);
 		kmem_free(lv);
 		lv = next;
 	}
@@ -376,9 +402,9 @@ xlog_cil_committed(
 	xfs_extent_busy_clear(mp, &ctx->busy_extents,
 			     (mp->m_flags & XFS_MOUNT_DISCARD) && !abort);
 
-	spin_lock(&ctx->cil->xc_cil_lock);
+	spin_lock(&ctx->cil->xc_push_lock);
 	list_del(&ctx->committing);
-	spin_unlock(&ctx->cil->xc_cil_lock);
+	spin_unlock(&ctx->cil->xc_push_lock);
 
 	xlog_cil_free_logvec(ctx->lv_chain);
 
@@ -433,7 +459,7 @@ xlog_cil_push(
 	down_write(&cil->xc_ctx_lock);
 	ctx = cil->xc_ctx;
 
-	spin_lock(&cil->xc_cil_lock);
+	spin_lock(&cil->xc_push_lock);
 	push_seq = cil->xc_push_seq;
 	ASSERT(push_seq <= ctx->sequence);
 
@@ -444,10 +470,10 @@ xlog_cil_push(
 	 */
 	if (list_empty(&cil->xc_cil)) {
 		cil->xc_push_seq = 0;
-		spin_unlock(&cil->xc_cil_lock);
+		spin_unlock(&cil->xc_push_lock);
 		goto out_skip;
 	}
-	spin_unlock(&cil->xc_cil_lock);
+	spin_unlock(&cil->xc_push_lock);
 
 
 	/* check for a previously pushed seqeunce */
@@ -515,9 +541,9 @@ xlog_cil_push(
 	 * that higher sequences will wait for us to write out a commit record
 	 * before they do.
 	 */
-	spin_lock(&cil->xc_cil_lock);
+	spin_lock(&cil->xc_push_lock);
 	list_add(&ctx->committing, &cil->xc_committing);
-	spin_unlock(&cil->xc_cil_lock);
+	spin_unlock(&cil->xc_push_lock);
 	up_write(&cil->xc_ctx_lock);
 
 	/*
@@ -552,7 +578,7 @@ xlog_cil_push(
 	 * order the commit records so replay will get them in the right order.
 	 */
 restart:
-	spin_lock(&cil->xc_cil_lock);
+	spin_lock(&cil->xc_push_lock);
 	list_for_each_entry(new_ctx, &cil->xc_committing, committing) {
 		/*
 		 * Higher sequences will wait for this one so skip them.
@@ -565,11 +591,11 @@ restart:
 			 * It is still being pushed! Wait for the push to
 			 * complete, then start again from the beginning.
 			 */
-			xlog_wait(&cil->xc_commit_wait, &cil->xc_cil_lock);
+			xlog_wait(&cil->xc_commit_wait, &cil->xc_push_lock);
 			goto restart;
 		}
 	}
-	spin_unlock(&cil->xc_cil_lock);
+	spin_unlock(&cil->xc_push_lock);
 
 	/* xfs_log_done always frees the ticket on error. */
 	commit_lsn = xfs_log_done(log->l_mp, tic, &commit_iclog, 0);
@@ -588,10 +614,10 @@ restart:
 	 * callbacks to the iclog we can assign the commit LSN to the context
 	 * and wake up anyone who is waiting for the commit to complete.
 	 */
-	spin_lock(&cil->xc_cil_lock);
+	spin_lock(&cil->xc_push_lock);
 	ctx->commit_lsn = commit_lsn;
 	wake_up_all(&cil->xc_commit_wait);
-	spin_unlock(&cil->xc_cil_lock);
+	spin_unlock(&cil->xc_push_lock);
 
 	/* release the hounds! */
 	return xfs_log_release_iclog(log->l_mp, commit_iclog);
@@ -644,12 +670,12 @@ xlog_cil_push_background(
 	if (cil->xc_ctx->space_used < XLOG_CIL_SPACE_LIMIT(log))
 		return;
 
-	spin_lock(&cil->xc_cil_lock);
+	spin_lock(&cil->xc_push_lock);
 	if (cil->xc_push_seq < cil->xc_current_sequence) {
 		cil->xc_push_seq = cil->xc_current_sequence;
 		queue_work(log->l_mp->m_cil_workqueue, &cil->xc_push_work);
 	}
-	spin_unlock(&cil->xc_cil_lock);
+	spin_unlock(&cil->xc_push_lock);
 
 }
 
@@ -672,14 +698,14 @@ xlog_cil_push_foreground(
 	 * If the CIL is empty or we've already pushed the sequence then
 	 * there's no work we need to do.
 	 */
-	spin_lock(&cil->xc_cil_lock);
+	spin_lock(&cil->xc_push_lock);
 	if (list_empty(&cil->xc_cil) || push_seq <= cil->xc_push_seq) {
-		spin_unlock(&cil->xc_cil_lock);
+		spin_unlock(&cil->xc_push_lock);
 		return;
 	}
 
 	cil->xc_push_seq = push_seq;
-	spin_unlock(&cil->xc_cil_lock);
+	spin_unlock(&cil->xc_push_lock);
 
 	/* do the push now */
 	xlog_cil_push(log);
@@ -706,43 +732,25 @@ xfs_log_commit_cil(
 	int			flags)
 {
 	struct xlog		*log = mp->m_log;
+	struct xfs_cil		*cil = log->l_cilp;
 	int			log_flags = 0;
-	struct xfs_log_vec	*log_vector;
 
 	if (flags & XFS_TRANS_RELEASE_LOG_RES)
 		log_flags = XFS_LOG_REL_PERM_RESERV;
 
-	/*
-	 * Do all the hard work of formatting items (including memory
-	 * allocation) outside the CIL context lock. This prevents stalling CIL
-	 * pushes when we are low on memory and a transaction commit spends a
-	 * lot of time in memory reclaim.
-	 */
-	log_vector = xlog_cil_prepare_log_vecs(tp);
-	if (!log_vector)
-		return ENOMEM;
-
 	/* lock out background commit */
-	down_read(&log->l_cilp->xc_ctx_lock);
-	if (commit_lsn)
-		*commit_lsn = log->l_cilp->xc_ctx->sequence;
+	down_read(&cil->xc_ctx_lock);
 
-	/* xlog_cil_insert_items() destroys log_vector list */
-	xlog_cil_insert_items(log, log_vector, tp->t_ticket);
+	xlog_cil_insert_items(log, tp);
 
 	/* check we didn't blow the reservation */
 	if (tp->t_ticket->t_curr_res < 0)
-		xlog_print_tic_res(log->l_mp, tp->t_ticket);
+		xlog_print_tic_res(mp, tp->t_ticket);
 
-	/* attach the transaction to the CIL if it has any busy extents */
-	if (!list_empty(&tp->t_busy)) {
-		spin_lock(&log->l_cilp->xc_cil_lock);
-		list_splice_init(&tp->t_busy,
-					&log->l_cilp->xc_ctx->busy_extents);
-		spin_unlock(&log->l_cilp->xc_cil_lock);
-	}
+	tp->t_commit_lsn = cil->xc_ctx->sequence;
+	if (commit_lsn)
+		*commit_lsn = tp->t_commit_lsn;
 
-	tp->t_commit_lsn = *commit_lsn;
 	xfs_log_done(mp, tp->t_ticket, NULL, log_flags);
 	xfs_trans_unreserve_and_mod_sb(tp);
 
@@ -757,11 +765,11 @@ xfs_log_commit_cil(
 	 * the log items. This affects (at least) processing of stale buffers,
 	 * inodes and EFIs.
 	 */
-	xfs_trans_free_items(tp, *commit_lsn, 0);
+	xfs_trans_free_items(tp, tp->t_commit_lsn, 0);
 
 	xlog_cil_push_background(log);
 
-	up_read(&log->l_cilp->xc_ctx_lock);
+	up_read(&cil->xc_ctx_lock);
 	return 0;
 }
 
@@ -800,7 +808,7 @@ xlog_cil_force_lsn(
 	 * on commits for those as well.
 	 */
 restart:
-	spin_lock(&cil->xc_cil_lock);
+	spin_lock(&cil->xc_push_lock);
 	list_for_each_entry(ctx, &cil->xc_committing, committing) {
 		if (ctx->sequence > sequence)
 			continue;
@@ -809,7 +817,7 @@ restart:
 			 * It is still being pushed! Wait for the push to
 			 * complete, then start again from the beginning.
 			 */
-			xlog_wait(&cil->xc_commit_wait, &cil->xc_cil_lock);
+			xlog_wait(&cil->xc_commit_wait, &cil->xc_push_lock);
 			goto restart;
 		}
 		if (ctx->sequence != sequence)
@@ -817,7 +825,7 @@ restart:
 		/* found it! */
 		commit_lsn = ctx->commit_lsn;
 	}
-	spin_unlock(&cil->xc_cil_lock);
+	spin_unlock(&cil->xc_push_lock);
 	return commit_lsn;
 }
 
@@ -875,6 +883,7 @@ xlog_cil_init(
 	INIT_LIST_HEAD(&cil->xc_cil);
 	INIT_LIST_HEAD(&cil->xc_committing);
 	spin_lock_init(&cil->xc_cil_lock);
+	spin_lock_init(&cil->xc_push_lock);
 	init_rwsem(&cil->xc_ctx_lock);
 	init_waitqueue_head(&cil->xc_commit_wait);