1 files changed, 360 insertions, 329 deletions

diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 1fd5787add99..00cd7f3a8f59 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -193,12 +193,8 @@ xlog_bread_noalign(
 	bp->b_io_length = nbblks;
 	bp->b_error = 0;
 
-	if (XFS_FORCED_SHUTDOWN(log->l_mp))
-		return -EIO;
-
-	xfs_buf_iorequest(bp);
-	error = xfs_buf_iowait(bp);
-	if (error)
+	error = xfs_buf_submit_wait(bp);
+	if (error && !XFS_FORCED_SHUTDOWN(log->l_mp))
 		xfs_buf_ioerror_alert(bp, __func__);
 	return error;
 }
@@ -378,12 +374,14 @@ xlog_recover_iodone(
 		 * We're not going to bother about retrying
 		 * this during recovery. One strike!
 		 */
-		xfs_buf_ioerror_alert(bp, __func__);
-		xfs_force_shutdown(bp->b_target->bt_mount,
-					SHUTDOWN_META_IO_ERROR);
+		if (!XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
+			xfs_buf_ioerror_alert(bp, __func__);
+			xfs_force_shutdown(bp->b_target->bt_mount,
+						SHUTDOWN_META_IO_ERROR);
+		}
 	}
 	bp->b_iodone = NULL;
-	xfs_buf_ioend(bp, 0);
+	xfs_buf_ioend(bp);
 }
 
 /*
@@ -1445,160 +1443,6 @@ xlog_clear_stale_blocks(
  ******************************************************************************
  */
 
-STATIC xlog_recover_t *
-xlog_recover_find_tid(
-	struct hlist_head	*head,
-	xlog_tid_t		tid)
-{
-	xlog_recover_t		*trans;
-
-	hlist_for_each_entry(trans, head, r_list) {
-		if (trans->r_log_tid == tid)
-			return trans;
-	}
-	return NULL;
-}
-
-STATIC void
-xlog_recover_new_tid(
-	struct hlist_head	*head,
-	xlog_tid_t		tid,
-	xfs_lsn_t		lsn)
-{
-	xlog_recover_t		*trans;
-
-	trans = kmem_zalloc(sizeof(xlog_recover_t), KM_SLEEP);
-	trans->r_log_tid   = tid;
-	trans->r_lsn	   = lsn;
-	INIT_LIST_HEAD(&trans->r_itemq);
-
-	INIT_HLIST_NODE(&trans->r_list);
-	hlist_add_head(&trans->r_list, head);
-}
-
-STATIC void
-xlog_recover_add_item(
-	struct list_head	*head)
-{
-	xlog_recover_item_t	*item;
-
-	item = kmem_zalloc(sizeof(xlog_recover_item_t), KM_SLEEP);
-	INIT_LIST_HEAD(&item->ri_list);
-	list_add_tail(&item->ri_list, head);
-}
-
-STATIC int
-xlog_recover_add_to_cont_trans(
-	struct xlog		*log,
-	struct xlog_recover	*trans,
-	xfs_caddr_t		dp,
-	int			len)
-{
-	xlog_recover_item_t	*item;
-	xfs_caddr_t		ptr, old_ptr;
-	int			old_len;
-
-	if (list_empty(&trans->r_itemq)) {
-		/* finish copying rest of trans header */
-		xlog_recover_add_item(&trans->r_itemq);
-		ptr = (xfs_caddr_t) &trans->r_theader +
-				sizeof(xfs_trans_header_t) - len;
-		memcpy(ptr, dp, len); /* d, s, l */
-		return 0;
-	}
-	/* take the tail entry */
-	item = list_entry(trans->r_itemq.prev, xlog_recover_item_t, ri_list);
-
-	old_ptr = item->ri_buf[item->ri_cnt-1].i_addr;
-	old_len = item->ri_buf[item->ri_cnt-1].i_len;
-
-	ptr = kmem_realloc(old_ptr, len+old_len, old_len, KM_SLEEP);
-	memcpy(&ptr[old_len], dp, len); /* d, s, l */
-	item->ri_buf[item->ri_cnt-1].i_len += len;
-	item->ri_buf[item->ri_cnt-1].i_addr = ptr;
-	trace_xfs_log_recover_item_add_cont(log, trans, item, 0);
-	return 0;
-}
-
-/*
- * The next region to add is the start of a new region.  It could be
- * a whole region or it could be the first part of a new region.  Because
- * of this, the assumption here is that the type and size fields of all
- * format structures fit into the first 32 bits of the structure.
- *
- * This works because all regions must be 32 bit aligned.  Therefore, we
- * either have both fields or we have neither field.  In the case we have
- * neither field, the data part of the region is zero length.  We only have
- * a log_op_header and can throw away the header since a new one will appear
- * later.  If we have at least 4 bytes, then we can determine how many regions
- * will appear in the current log item.
- */
-STATIC int
-xlog_recover_add_to_trans(
-	struct xlog		*log,
-	struct xlog_recover	*trans,
-	xfs_caddr_t		dp,
-	int			len)
-{
-	xfs_inode_log_format_t	*in_f;			/* any will do */
-	xlog_recover_item_t	*item;
-	xfs_caddr_t		ptr;
-
-	if (!len)
-		return 0;
-	if (list_empty(&trans->r_itemq)) {
-		/* we need to catch log corruptions here */
-		if (*(uint *)dp != XFS_TRANS_HEADER_MAGIC) {
-			xfs_warn(log->l_mp, "%s: bad header magic number",
-				__func__);
-			ASSERT(0);
-			return -EIO;
-		}
-		if (len == sizeof(xfs_trans_header_t))
-			xlog_recover_add_item(&trans->r_itemq);
-		memcpy(&trans->r_theader, dp, len); /* d, s, l */
-		return 0;
-	}
-
-	ptr = kmem_alloc(len, KM_SLEEP);
-	memcpy(ptr, dp, len);
-	in_f = (xfs_inode_log_format_t *)ptr;
-
-	/* take the tail entry */
-	item = list_entry(trans->r_itemq.prev, xlog_recover_item_t, ri_list);
-	if (item->ri_total != 0 &&
-	     item->ri_total == item->ri_cnt) {
-		/* tail item is in use, get a new one */
-		xlog_recover_add_item(&trans->r_itemq);
-		item = list_entry(trans->r_itemq.prev,
-					xlog_recover_item_t, ri_list);
-	}
-
-	if (item->ri_total == 0) {		/* first region to be added */
-		if (in_f->ilf_size == 0 ||
-		    in_f->ilf_size > XLOG_MAX_REGIONS_IN_ITEM) {
-			xfs_warn(log->l_mp,
-		"bad number of regions (%d) in inode log format",
-				  in_f->ilf_size);
-			ASSERT(0);
-			kmem_free(ptr);
-			return -EIO;
-		}
-
-		item->ri_total = in_f->ilf_size;
-		item->ri_buf =
-			kmem_zalloc(item->ri_total * sizeof(xfs_log_iovec_t),
-				    KM_SLEEP);
-	}
-	ASSERT(item->ri_total > item->ri_cnt);
-	/* Description region is ri_buf[0] */
-	item->ri_buf[item->ri_cnt].i_addr = ptr;
-	item->ri_buf[item->ri_cnt].i_len  = len;
-	item->ri_cnt++;
-	trace_xfs_log_recover_item_add(log, trans, item, 0);
-	return 0;
-}
-
 /*
  * Sort the log items in the transaction.
  *
@@ -3254,31 +3098,6 @@ xlog_recover_do_icreate_pass2(
 	return 0;
 }
 
-/*
- * Free up any resources allocated by the transaction
- *
- * Remember that EFIs, EFDs, and IUNLINKs are handled later.
- */
-STATIC void
-xlog_recover_free_trans(
-	struct xlog_recover	*trans)
-{
-	xlog_recover_item_t	*item, *n;
-	int			i;
-
-	list_for_each_entry_safe(item, n, &trans->r_itemq, ri_list) {
-		/* Free the regions in the item. */
-		list_del(&item->ri_list);
-		for (i = 0; i < item->ri_cnt; i++)
-			kmem_free(item->ri_buf[i].i_addr);
-		/* Free the item itself */
-		kmem_free(item->ri_buf);
-		kmem_free(item);
-	}
-	/* Free the transaction recover structure */
-	kmem_free(trans);
-}
-
 STATIC void
 xlog_recover_buffer_ra_pass2(
 	struct xlog                     *log,
@@ -3528,22 +3347,309 @@ out:
 	if (!list_empty(&done_list))
 		list_splice_init(&done_list, &trans->r_itemq);
 
-	xlog_recover_free_trans(trans);
-
 	error2 = xfs_buf_delwri_submit(&buffer_list);
 	return error ? error : error2;
 }
 
+STATIC void
+xlog_recover_add_item(
+	struct list_head	*head)
+{
+	xlog_recover_item_t	*item;
+
+	item = kmem_zalloc(sizeof(xlog_recover_item_t), KM_SLEEP);
+	INIT_LIST_HEAD(&item->ri_list);
+	list_add_tail(&item->ri_list, head);
+}
+
 STATIC int
-xlog_recover_unmount_trans(
-	struct xlog		*log)
+xlog_recover_add_to_cont_trans(
+	struct xlog		*log,
+	struct xlog_recover	*trans,
+	xfs_caddr_t		dp,
+	int			len)
 {
-	/* Do nothing now */
-	xfs_warn(log->l_mp, "%s: Unmount LR", __func__);
+	xlog_recover_item_t	*item;
+	xfs_caddr_t		ptr, old_ptr;
+	int			old_len;
+
+	if (list_empty(&trans->r_itemq)) {
+		/* finish copying rest of trans header */
+		xlog_recover_add_item(&trans->r_itemq);
+		ptr = (xfs_caddr_t) &trans->r_theader +
+				sizeof(xfs_trans_header_t) - len;
+		memcpy(ptr, dp, len);
+		return 0;
+	}
+	/* take the tail entry */
+	item = list_entry(trans->r_itemq.prev, xlog_recover_item_t, ri_list);
+
+	old_ptr = item->ri_buf[item->ri_cnt-1].i_addr;
+	old_len = item->ri_buf[item->ri_cnt-1].i_len;
+
+	ptr = kmem_realloc(old_ptr, len+old_len, old_len, KM_SLEEP);
+	memcpy(&ptr[old_len], dp, len);
+	item->ri_buf[item->ri_cnt-1].i_len += len;
+	item->ri_buf[item->ri_cnt-1].i_addr = ptr;
+	trace_xfs_log_recover_item_add_cont(log, trans, item, 0);
+	return 0;
+}
+
+/*
+ * The next region to add is the start of a new region.  It could be
+ * a whole region or it could be the first part of a new region.  Because
+ * of this, the assumption here is that the type and size fields of all
+ * format structures fit into the first 32 bits of the structure.
+ *
+ * This works because all regions must be 32 bit aligned.  Therefore, we
+ * either have both fields or we have neither field.  In the case we have
+ * neither field, the data part of the region is zero length.  We only have
+ * a log_op_header and can throw away the header since a new one will appear
+ * later.  If we have at least 4 bytes, then we can determine how many regions
+ * will appear in the current log item.
+ */
+STATIC int
+xlog_recover_add_to_trans(
+	struct xlog		*log,
+	struct xlog_recover	*trans,
+	xfs_caddr_t		dp,
+	int			len)
+{
+	xfs_inode_log_format_t	*in_f;			/* any will do */
+	xlog_recover_item_t	*item;
+	xfs_caddr_t		ptr;
+
+	if (!len)
+		return 0;
+	if (list_empty(&trans->r_itemq)) {
+		/* we need to catch log corruptions here */
+		if (*(uint *)dp != XFS_TRANS_HEADER_MAGIC) {
+			xfs_warn(log->l_mp, "%s: bad header magic number",
+				__func__);
+			ASSERT(0);
+			return -EIO;
+		}
+		if (len == sizeof(xfs_trans_header_t))
+			xlog_recover_add_item(&trans->r_itemq);
+		memcpy(&trans->r_theader, dp, len);
+		return 0;
+	}
+
+	ptr = kmem_alloc(len, KM_SLEEP);
+	memcpy(ptr, dp, len);
+	in_f = (xfs_inode_log_format_t *)ptr;
+
+	/* take the tail entry */
+	item = list_entry(trans->r_itemq.prev, xlog_recover_item_t, ri_list);
+	if (item->ri_total != 0 &&
+	     item->ri_total == item->ri_cnt) {
+		/* tail item is in use, get a new one */
+		xlog_recover_add_item(&trans->r_itemq);
+		item = list_entry(trans->r_itemq.prev,
+					xlog_recover_item_t, ri_list);
+	}
+
+	if (item->ri_total == 0) {		/* first region to be added */
+		if (in_f->ilf_size == 0 ||
+		    in_f->ilf_size > XLOG_MAX_REGIONS_IN_ITEM) {
+			xfs_warn(log->l_mp,
+		"bad number of regions (%d) in inode log format",
+				  in_f->ilf_size);
+			ASSERT(0);
+			kmem_free(ptr);
+			return -EIO;
+		}
+
+		item->ri_total = in_f->ilf_size;
+		item->ri_buf =
+			kmem_zalloc(item->ri_total * sizeof(xfs_log_iovec_t),
+				    KM_SLEEP);
+	}
+	ASSERT(item->ri_total > item->ri_cnt);
+	/* Description region is ri_buf[0] */
+	item->ri_buf[item->ri_cnt].i_addr = ptr;
+	item->ri_buf[item->ri_cnt].i_len  = len;
+	item->ri_cnt++;
+	trace_xfs_log_recover_item_add(log, trans, item, 0);
 	return 0;
 }
 
 /*
+ * Free up any resources allocated by the transaction
+ *
+ * Remember that EFIs, EFDs, and IUNLINKs are handled later.
+ */
+STATIC void
+xlog_recover_free_trans(
+	struct xlog_recover	*trans)
+{
+	xlog_recover_item_t	*item, *n;
+	int			i;
+
+	list_for_each_entry_safe(item, n, &trans->r_itemq, ri_list) {
+		/* Free the regions in the item. */
+		list_del(&item->ri_list);
+		for (i = 0; i < item->ri_cnt; i++)
+			kmem_free(item->ri_buf[i].i_addr);
+		/* Free the item itself */
+		kmem_free(item->ri_buf);
+		kmem_free(item);
+	}
+	/* Free the transaction recover structure */
+	kmem_free(trans);
+}
+
+/*
+ * On error or completion, trans is freed.
+ */
+STATIC int
+xlog_recovery_process_trans(
+	struct xlog		*log,
+	struct xlog_recover	*trans,
+	xfs_caddr_t		dp,
+	unsigned int		len,
+	unsigned int		flags,
+	int			pass)
+{
+	int			error = 0;
+	bool			freeit = false;
+
+	/* mask off ophdr transaction container flags */
+	flags &= ~XLOG_END_TRANS;
+	if (flags & XLOG_WAS_CONT_TRANS)
+		flags &= ~XLOG_CONTINUE_TRANS;
+
+	/*
+	 * Callees must not free the trans structure. We'll decide if we need to
+	 * free it or not based on the operation being done and it's result.
+	 */
+	switch (flags) {
+	/* expected flag values */
+	case 0:
+	case XLOG_CONTINUE_TRANS:
+		error = xlog_recover_add_to_trans(log, trans, dp, len);
+		break;
+	case XLOG_WAS_CONT_TRANS:
+		error = xlog_recover_add_to_cont_trans(log, trans, dp, len);
+		break;
+	case XLOG_COMMIT_TRANS:
+		error = xlog_recover_commit_trans(log, trans, pass);
+		/* success or fail, we are now done with this transaction. */
+		freeit = true;
+		break;
+
+	/* unexpected flag values */
+	case XLOG_UNMOUNT_TRANS:
+		/* just skip trans */
+		xfs_warn(log->l_mp, "%s: Unmount LR", __func__);
+		freeit = true;
+		break;
+	case XLOG_START_TRANS:
+	default:
+		xfs_warn(log->l_mp, "%s: bad flag 0x%x", __func__, flags);
+		ASSERT(0);
+		error = -EIO;
+		break;
+	}
+	if (error || freeit)
+		xlog_recover_free_trans(trans);
+	return error;
+}
+
+/*
+ * Lookup the transaction recovery structure associated with the ID in the
+ * current ophdr. If the transaction doesn't exist and the start flag is set in
+ * the ophdr, then allocate a new transaction for future ID matches to find.
+ * Either way, return what we found during the lookup - an existing transaction
+ * or nothing.
+ */
+STATIC struct xlog_recover *
+xlog_recover_ophdr_to_trans(
+	struct hlist_head	rhash[],
+	struct xlog_rec_header	*rhead,
+	struct xlog_op_header	*ohead)
+{
+	struct xlog_recover	*trans;
+	xlog_tid_t		tid;
+	struct hlist_head	*rhp;
+
+	tid = be32_to_cpu(ohead->oh_tid);
+	rhp = &rhash[XLOG_RHASH(tid)];
+	hlist_for_each_entry(trans, rhp, r_list) {
+		if (trans->r_log_tid == tid)
+			return trans;
+	}
+
+	/*
+	 * skip over non-start transaction headers - we could be
+	 * processing slack space before the next transaction starts
+	 */
+	if (!(ohead->oh_flags & XLOG_START_TRANS))
+		return NULL;
+
+	ASSERT(be32_to_cpu(ohead->oh_len) == 0);
+
+	/*
+	 * This is a new transaction so allocate a new recovery container to
+	 * hold the recovery ops that will follow.
+	 */
+	trans = kmem_zalloc(sizeof(struct xlog_recover), KM_SLEEP);
+	trans->r_log_tid = tid;
+	trans->r_lsn = be64_to_cpu(rhead->h_lsn);
+	INIT_LIST_HEAD(&trans->r_itemq);
+	INIT_HLIST_NODE(&trans->r_list);
+	hlist_add_head(&trans->r_list, rhp);
+
+	/*
+	 * Nothing more to do for this ophdr. Items to be added to this new
+	 * transaction will be in subsequent ophdr containers.
+	 */
+	return NULL;
+}
+
+STATIC int
+xlog_recover_process_ophdr(
+	struct xlog		*log,
+	struct hlist_head	rhash[],
+	struct xlog_rec_header	*rhead,
+	struct xlog_op_header	*ohead,
+	xfs_caddr_t		dp,
+	xfs_caddr_t		end,
+	int			pass)
+{
+	struct xlog_recover	*trans;
+	unsigned int		len;
+
+	/* Do we understand who wrote this op? */
+	if (ohead->oh_clientid != XFS_TRANSACTION &&
+	    ohead->oh_clientid != XFS_LOG) {
+		xfs_warn(log->l_mp, "%s: bad clientid 0x%x",
+			__func__, ohead->oh_clientid);
+		ASSERT(0);
+		return -EIO;
+	}
+
+	/*
+	 * Check the ophdr contains all the data it is supposed to contain.
+	 */
+	len = be32_to_cpu(ohead->oh_len);
+	if (dp + len > end) {
+		xfs_warn(log->l_mp, "%s: bad length 0x%x", __func__, len);
+		WARN_ON(1);
+		return -EIO;
+	}
+
+	trans = xlog_recover_ophdr_to_trans(rhash, rhead, ohead);
+	if (!trans) {
+		/* nothing to do, so skip over this ophdr */
+		return 0;
+	}
+
+	return xlog_recovery_process_trans(log, trans, dp, len,
+					   ohead->oh_flags, pass);
+}
+
+/*
  * There are two valid states of the r_state field.  0 indicates that the
  * transaction structure is in a normal state.  We have either seen the
  * start of the transaction or the last operation we added was not a partial
@@ -3560,86 +3666,30 @@ xlog_recover_process_data(
 	xfs_caddr_t		dp,
 	int			pass)
 {
-	xfs_caddr_t		lp;
+	struct xlog_op_header	*ohead;
+	xfs_caddr_t		end;
 	int			num_logops;
-	xlog_op_header_t	*ohead;
-	xlog_recover_t		*trans;
-	xlog_tid_t		tid;
 	int			error;
-	unsigned long		hash;
-	uint			flags;
 
-	lp = dp + be32_to_cpu(rhead->h_len);
+	end = dp + be32_to_cpu(rhead->h_len);
 	num_logops = be32_to_cpu(rhead->h_num_logops);
 
 	/* check the log format matches our own - else we can't recover */
 	if (xlog_header_check_recover(log->l_mp, rhead))
 		return -EIO;
 
-	while ((dp < lp) && num_logops) {
-		ASSERT(dp + sizeof(xlog_op_header_t) <= lp);
-		ohead = (xlog_op_header_t *)dp;
-		dp += sizeof(xlog_op_header_t);
-		if (ohead->oh_clientid != XFS_TRANSACTION &&
-		    ohead->oh_clientid != XFS_LOG) {
-			xfs_warn(log->l_mp, "%s: bad clientid 0x%x",
-					__func__, ohead->oh_clientid);
-			ASSERT(0);
-			return -EIO;
-		}
-		tid = be32_to_cpu(ohead->oh_tid);
-		hash = XLOG_RHASH(tid);
-		trans = xlog_recover_find_tid(&rhash[hash], tid);
-		if (trans == NULL) {		   /* not found; add new tid */
-			if (ohead->oh_flags & XLOG_START_TRANS)
-				xlog_recover_new_tid(&rhash[hash], tid,
-					be64_to_cpu(rhead->h_lsn));
-		} else {
-			if (dp + be32_to_cpu(ohead->oh_len) > lp) {
-				xfs_warn(log->l_mp, "%s: bad length 0x%x",
-					__func__, be32_to_cpu(ohead->oh_len));
-				WARN_ON(1);
-				return -EIO;
-			}
-			flags = ohead->oh_flags & ~XLOG_END_TRANS;
-			if (flags & XLOG_WAS_CONT_TRANS)
-				flags &= ~XLOG_CONTINUE_TRANS;
-			switch (flags) {
-			case XLOG_COMMIT_TRANS:
-				error = xlog_recover_commit_trans(log,
-								trans, pass);
-				break;
-			case XLOG_UNMOUNT_TRANS:
-				error = xlog_recover_unmount_trans(log);
-				break;
-			case XLOG_WAS_CONT_TRANS:
-				error = xlog_recover_add_to_cont_trans(log,
-						trans, dp,
-						be32_to_cpu(ohead->oh_len));
-				break;
-			case XLOG_START_TRANS:
-				xfs_warn(log->l_mp, "%s: bad transaction",
-					__func__);
-				ASSERT(0);
-				error = -EIO;
-				break;
-			case 0:
-			case XLOG_CONTINUE_TRANS:
-				error = xlog_recover_add_to_trans(log, trans,
-						dp, be32_to_cpu(ohead->oh_len));
-				break;
-			default:
-				xfs_warn(log->l_mp, "%s: bad flag 0x%x",
-					__func__, flags);
-				ASSERT(0);
-				error = -EIO;
-				break;
-			}
-			if (error) {
-				xlog_recover_free_trans(trans);
-				return error;
-			}
-		}
+	while ((dp < end) && num_logops) {
+
+		ohead = (struct xlog_op_header *)dp;
+		dp += sizeof(*ohead);
+		ASSERT(dp <= end);
+
+		/* errors will abort recovery */
+		error = xlog_recover_process_ophdr(log, rhash, rhead, ohead,
+						    dp, end, pass);
+		if (error)
+			return error;
+
 		dp += be32_to_cpu(ohead->oh_len);
 		num_logops--;
 	}
@@ -4132,41 +4182,13 @@ xlog_do_recovery_pass(
 	}
 
 	memset(rhash, 0, sizeof(rhash));
-	if (tail_blk <= head_blk) {
-		for (blk_no = tail_blk; blk_no < head_blk; ) {
-			error = xlog_bread(log, blk_no, hblks, hbp, &offset);
-			if (error)
-				goto bread_err2;
-
-			rhead = (xlog_rec_header_t *)offset;
-			error = xlog_valid_rec_header(log, rhead, blk_no);
-			if (error)
-				goto bread_err2;
-
-			/* blocks in data section */
-			bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
-			error = xlog_bread(log, blk_no + hblks, bblks, dbp,
-					   &offset);
-			if (error)
-				goto bread_err2;
-
-			error = xlog_unpack_data(rhead, offset, log);
-			if (error)
-				goto bread_err2;
-
-			error = xlog_recover_process_data(log,
-						rhash, rhead, offset, pass);
-			if (error)
-				goto bread_err2;
-			blk_no += bblks + hblks;
-		}
-	} else {
+	blk_no = tail_blk;
+	if (tail_blk > head_blk) {
 		/*
 		 * Perform recovery around the end of the physical log.
 		 * When the head is not on the same cycle number as the tail,
-		 * we can't do a sequential recovery as above.
+		 * we can't do a sequential recovery.
 		 */
-		blk_no = tail_blk;
 		while (blk_no < log->l_logBBsize) {
 			/*
 			 * Check for header wrapping around physical end-of-log
@@ -4280,34 +4302,35 @@ xlog_do_recovery_pass(
 
 		ASSERT(blk_no >= log->l_logBBsize);
 		blk_no -= log->l_logBBsize;
+	}
 
-		/* read first part of physical log */
-		while (blk_no < head_blk) {
-			error = xlog_bread(log, blk_no, hblks, hbp, &offset);
-			if (error)
-				goto bread_err2;
+	/* read first part of physical log */
+	while (blk_no < head_blk) {
+		error = xlog_bread(log, blk_no, hblks, hbp, &offset);
+		if (error)
+			goto bread_err2;
 
-			rhead = (xlog_rec_header_t *)offset;
-			error = xlog_valid_rec_header(log, rhead, blk_no);
-			if (error)
-				goto bread_err2;
+		rhead = (xlog_rec_header_t *)offset;
+		error = xlog_valid_rec_header(log, rhead, blk_no);
+		if (error)
+			goto bread_err2;
 
-			bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
-			error = xlog_bread(log, blk_no+hblks, bblks, dbp,
-					   &offset);
-			if (error)
-				goto bread_err2;
+		/* blocks in data section */
+		bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
+		error = xlog_bread(log, blk_no+hblks, bblks, dbp,
+				   &offset);
+		if (error)
+			goto bread_err2;
 
-			error = xlog_unpack_data(rhead, offset, log);
-			if (error)
-				goto bread_err2;
+		error = xlog_unpack_data(rhead, offset, log);
+		if (error)
+			goto bread_err2;
 
-			error = xlog_recover_process_data(log, rhash,
-							rhead, offset, pass);
-			if (error)
-				goto bread_err2;
-			blk_no += bblks + hblks;
-		}
+		error = xlog_recover_process_data(log, rhash,
+						rhead, offset, pass);
+		if (error)
+			goto bread_err2;
+		blk_no += bblks + hblks;
 	}
 
  bread_err2:
@@ -4427,16 +4450,12 @@ xlog_do_recover(
 	XFS_BUF_UNASYNC(bp);
 	bp->b_ops = &xfs_sb_buf_ops;
 
-	if (XFS_FORCED_SHUTDOWN(log->l_mp)) {
-		xfs_buf_relse(bp);
-		return -EIO;
-	}
-
-	xfs_buf_iorequest(bp);
-	error = xfs_buf_iowait(bp);
+	error = xfs_buf_submit_wait(bp);
 	if (error) {
-		xfs_buf_ioerror_alert(bp, __func__);
-		ASSERT(0);
+		if (!XFS_FORCED_SHUTDOWN(log->l_mp)) {
+			xfs_buf_ioerror_alert(bp, __func__);
+			ASSERT(0);
+		}
 		xfs_buf_relse(bp);
 		return error;
 	}
@@ -4509,6 +4528,18 @@ xlog_recover(
 			return -EINVAL;
 		}
 
+		/*
+		 * Delay log recovery if the debug hook is set. This is debug
+		 * instrumention to coordinate simulation of I/O failures with
+		 * log recovery.
+		 */
+		if (xfs_globals.log_recovery_delay) {
+			xfs_notice(log->l_mp,
+				"Delaying log recovery for %d seconds.",
+				xfs_globals.log_recovery_delay);
+			msleep(xfs_globals.log_recovery_delay * 1000);
+		}
+
 		xfs_notice(log->l_mp, "Starting recovery (logdev: %s)",
 				log->l_mp->m_logname ? log->l_mp->m_logname
 						     : "internal");