[Devel] [PATCH rh7 2/4] ploop: implement PLOOP_IOC_PUSH_BACKUP_IO

Maxim Patlasov mpatlasov at virtuozzo.com
Fri Apr 29 20:20:03 PDT 2016


The ioctl(PLOOP_IOC_PUSH_BACKUP_IO) has two mode of operation:

1) ctl.direction=PLOOP_READ tells userspace which cluster-blocks to
push out-of-band; moves processed preq-s from pending_tree to reported_tree

2) ctl.direction=PLOOP_WRITE tells kernel which cluster-blocks were pushed --
they are either ordinarily processed preq-s or out-of-band ones; the kernel
match the blocks to preq-s in reported_tree and re-schedules them.

Signed-off-by: Maxim Patlasov <mpatlasov at virtuozzo.com>
---
 drivers/block/ploop/dev.c         |  105 ++++++++++++++++++++
 drivers/block/ploop/push_backup.c |  197 +++++++++++++++++++++++++++++++++++++
 drivers/block/ploop/push_backup.h |    5 +
 include/linux/ploop/ploop_if.h    |   23 ++++
 4 files changed, 330 insertions(+)

diff --git a/drivers/block/ploop/dev.c b/drivers/block/ploop/dev.c
index 23da9f5..2a77d2e 100644
--- a/drivers/block/ploop/dev.c
+++ b/drivers/block/ploop/dev.c
@@ -4529,6 +4529,108 @@ pb_init_done:
 	return rc;
 }
 
+static int ploop_push_backup_io_read(struct ploop_device *plo, unsigned long arg,
+				     struct ploop_push_backup_io_ctl *ctl)
+{
+	struct ploop_push_backup_ctl_extent *e;
+	unsigned n_extents = 0;
+	int rc = 0;
+
+	e = kmalloc(sizeof(*e) * ctl->n_extents, GFP_KERNEL);
+	if (!e)
+		return -ENOMEM;
+
+	while (n_extents < ctl->n_extents) {
+		cluster_t clu, len;
+		rc = ploop_pb_get_pending(plo->pbd, &clu, &len, n_extents);
+		if (rc)
+			goto io_read_done;
+
+		e[n_extents].clu = clu;
+		e[n_extents].len = len;
+		n_extents++;
+	}
+
+	rc = -EFAULT;
+	ctl->n_extents = n_extents;
+	if (copy_to_user((void*)arg, ctl, sizeof(*ctl)))
+		goto io_read_done;
+	if (n_extents &&
+	    copy_to_user((void*)(arg + sizeof(*ctl)), e,
+			 n_extents * sizeof(*e)))
+			goto io_read_done;
+	rc = 0;
+
+io_read_done:
+	kfree(e);
+	return rc;
+}
+
+static int ploop_push_backup_io_write(struct ploop_device *plo, unsigned long arg,
+				      struct ploop_push_backup_io_ctl *ctl)
+{
+	struct ploop_push_backup_ctl_extent *e;
+	unsigned i;
+	int rc = 0;
+
+	e = kmalloc(sizeof(*e) * ctl->n_extents, GFP_KERNEL);
+	if (!e)
+		return -ENOMEM;
+
+	rc = -EFAULT;
+	if (copy_from_user(e, (void*)(arg + sizeof(*ctl)),
+			   ctl->n_extents * sizeof(*e)))
+		goto io_write_done;
+
+	rc = 0;
+	for (i = 0; i < ctl->n_extents; i++) {
+		cluster_t j;
+		for (j = e[i].clu; j < e[i].clu + e[i].len; j++)
+			ploop_pb_put_reported(plo->pbd, j, 1);
+                /* OPTIMIZE ME LATER: like this:
+		 * ploop_pb_put_reported(plo->pbd, e[i].clu, e[i].len); */
+	}
+
+io_write_done:
+	kfree(e);
+	return rc;
+}
+
+static int ploop_push_backup_io(struct ploop_device *plo, unsigned long arg)
+{
+	struct ploop_push_backup_io_ctl ctl;
+	struct ploop_pushbackup_desc *pbd = plo->pbd;
+
+	if (list_empty(&plo->map.delta_list))
+		return -ENOENT;
+
+	if (plo->maintenance_type != PLOOP_MNTN_PUSH_BACKUP)
+		return -EINVAL;
+
+	BUG_ON (!pbd);
+
+	if (copy_from_user(&ctl, (void*)arg, sizeof(ctl)))
+		return -EFAULT;
+
+	if (!ctl.n_extents)
+		return -EINVAL;
+
+	if (ploop_pb_check_uuid(pbd, ctl.cbt_uuid)) {
+		printk("ploop(%d): PUSH_BACKUP_IO uuid mismatch\n",
+		       plo->index);
+		return -EINVAL;
+	}
+
+	switch(ctl.direction) {
+	case PLOOP_READ:
+		return ploop_push_backup_io_read(plo, arg, &ctl);
+	case PLOOP_WRITE:
+		return ploop_push_backup_io_write(plo, arg, &ctl);
+	}
+
+	return -EINVAL;
+}
+
 static int ploop_push_backup_stop(struct ploop_device *plo, unsigned long arg)
 {
 	struct ploop_pushbackup_desc *pbd = plo->pbd;
@@ -4667,6 +4769,9 @@ static int ploop_ioctl(struct block_device *bdev, fmode_t fmode, unsigned int cm
 	case PLOOP_IOC_PUSH_BACKUP_INIT:
 		err = ploop_push_backup_init(plo, arg);
 		break;
+	case PLOOP_IOC_PUSH_BACKUP_IO:
+		err = ploop_push_backup_io(plo, arg);
+		break;
 	case PLOOP_IOC_PUSH_BACKUP_STOP:
 		err = ploop_push_backup_stop(plo, arg);
 		break;
diff --git a/drivers/block/ploop/push_backup.c b/drivers/block/ploop/push_backup.c
index ecc9862..477caf7 100644
--- a/drivers/block/ploop/push_backup.c
+++ b/drivers/block/ploop/push_backup.c
@@ -256,6 +256,89 @@ int ploop_pb_copy_cbt_to_user(struct ploop_pushbackup_desc *pbd, char *user_addr
 	return 0;
 }
 
+static void ploop_pb_add_req_to_tree(struct ploop_request *preq,
+				     struct rb_root *tree)
+{
+	struct rb_node ** p = &tree->rb_node;
+	struct rb_node *parent = NULL;
+	struct ploop_request * pr;
+
+	while (*p) {
+		parent = *p;
+		pr = rb_entry(parent, struct ploop_request, reloc_link);
+		BUG_ON (preq->req_cluster == pr->req_cluster);
+
+		if (preq->req_cluster < pr->req_cluster)
+			p = &(*p)->rb_left;
+		else
+			p = &(*p)->rb_right;
+	}
+
+	rb_link_node(&preq->reloc_link, parent, p);
+	rb_insert_color(&preq->reloc_link, tree);
+}
+
+static void ploop_pb_add_req_to_reported(struct ploop_pushbackup_desc *pbd,
+					 struct ploop_request *preq)
+{
+	ploop_pb_add_req_to_tree(preq, &pbd->reported_tree);
+}
+
+static struct ploop_request *ploop_pb_get_req_from_tree(struct rb_root *tree,
+							cluster_t clu)
+{
+	struct rb_node *n = tree->rb_node;
+	struct ploop_request *p;
+
+	while (n) {
+		p = rb_entry(n, struct ploop_request, reloc_link);
+
+		if (clu < p->req_cluster)
+			n = n->rb_left;
+		else if (clu > p->req_cluster)
+			n = n->rb_right;
+		else {
+			rb_erase(&p->reloc_link, tree);
+			return p;
+		}
+	}
+	return NULL;
+}
+
+static struct ploop_request *
+ploop_pb_get_first_req_from_tree(struct rb_root *tree)
+{
+	static struct ploop_request *p;
+	struct rb_node *n = rb_first(tree);
+
+	if (!n)
+		return NULL;
+
+	p = rb_entry(n, struct ploop_request, reloc_link);
+	rb_erase(&p->reloc_link, tree);
+	return p;
+}
+
+static struct ploop_request *
+ploop_pb_get_first_req_from_pending(struct ploop_pushbackup_desc *pbd)
+{
+	return ploop_pb_get_first_req_from_tree(&pbd->pending_tree);
+}
+
+static struct ploop_request *
+ploop_pb_get_req_from_pending(struct ploop_pushbackup_desc *pbd,
+			      cluster_t clu)
+{
+	return ploop_pb_get_req_from_tree(&pbd->pending_tree, clu);
+}
+
+static struct ploop_request *
+ploop_pb_get_req_from_reported(struct ploop_pushbackup_desc *pbd,
+			       cluster_t clu)
+{
+	return ploop_pb_get_req_from_tree(&pbd->reported_tree, clu);
+}
+
 unsigned long ploop_pb_stop(struct ploop_pushbackup_desc *pbd)
 {
 	if (pbd == NULL)
@@ -269,3 +352,117 @@ unsigned long ploop_pb_stop(struct ploop_pushbackup_desc *pbd)
 
 	return 0;
 }
+
+int ploop_pb_get_pending(struct ploop_pushbackup_desc *pbd,
+			 cluster_t *clu_p, cluster_t *len_p, unsigned n_done)
+{
+	bool blocking  = !n_done;
+	struct ploop_request *preq;
+	int err = 0;
+
+	spin_lock(&pbd->ppb_lock);
+
+	/* OPTIMIZE ME LATER: rb_first() once, then rb_next() */
+	preq = ploop_pb_get_first_req_from_pending(pbd);
+	if (!preq) {
+		struct ploop_device *plo = pbd->plo;
+
+		if (!blocking) {
+			err = -ENOENT;
+			goto get_pending_unlock;
+		}
+
+                /* blocking case */
+		pbd->ppb_waiting = true;
+		spin_unlock(&pbd->ppb_lock);
+
+		mutex_unlock(&plo->ctl_mutex);
+		err = wait_for_completion_interruptible(&pbd->ppb_comp);
+		mutex_lock(&plo->ctl_mutex);
+
+		if (plo->pbd != pbd)
+			return -EINTR;
+
+		spin_lock(&pbd->ppb_lock);
+		pbd->ppb_waiting = false;
+		init_completion(&pbd->ppb_comp);
+
+		preq = ploop_pb_get_first_req_from_pending(pbd);
+		if (!preq) {
+			if (!test_bit(PLOOP_S_PUSH_BACKUP, &plo->state))
+				err = -EINTR;
+			else if (signal_pending(current))
+				err = -ERESTARTSYS;
+			else err = -ENOENT;
+
+			goto get_pending_unlock;
+		}
+	}
+
+	ploop_pb_add_req_to_reported(pbd, preq);
+
+	*clu_p = preq->req_cluster;
+	*len_p = 1;
+
+get_pending_unlock:
+	spin_unlock(&pbd->ppb_lock);
+	return err;
+}
+
+void ploop_pb_put_reported(struct ploop_pushbackup_desc *pbd,
+			   cluster_t clu, cluster_t len)
+{
+	struct ploop_request *preq;
+	int n_found = 0;
+
+	/* OPTIMIZE ME LATER: find leftmost item for [clu, clu+len),
+	 * then rb_next() while req_cluster < clu+len.
+	 * Do this firstly for reported, then for pending */
+	BUG_ON(len != 1);
+
+	spin_lock(&pbd->ppb_lock);
+
+	preq = ploop_pb_get_req_from_reported(pbd, clu);
+	if (!preq)
+		preq = ploop_pb_get_req_from_pending(pbd, clu);
+	else
+		n_found++;
+
+	/*
+	 * If preq not found above, it's unsolicited report. Then it's
+	 * enough to have corresponding bit set in reported_map because if
+	 * any WRITE-request comes afterwards, ploop_pb_preq_add_pending()
+	 * fails and ploop_thread will clear corresponding bit in ppb_map
+	 * -- see "push_backup special processing" in ploop_entry_request()
+	 * for details.
+	 */
+
+	/*
+	 * "If .. else if .." below will be fully reworked when switching
+	 * from pbd->ppb_offset to pbd->reported_map. All we need here is
+	 * actaully simply to set bits corresponding to [clu, clu+len) in
+	 * pbd->reported_map.
+	 */
+	if (pbd->ppb_offset >= clu) { /* lucky strike */
+		if (clu + len > pbd->ppb_offset) {
+			pbd->ppb_offset = clu + len;
+		}
+	} else if (n_found != len) { /* a hole, bad luck */
+		printk("ploop: push_backup ERR: off=%u ext=[%u, %u) found %d\n",
+		       pbd->ppb_offset, clu, clu + len, n_found);
+	}
+
+	spin_unlock(&pbd->ppb_lock);
+
+	if (preq) {
+		struct ploop_device *plo = preq->plo;
+		BUG_ON(preq->req_cluster != clu);
+		BUG_ON(plo != pbd->plo);
+
+		spin_lock_irq(&plo->lock);
+		list_add_tail(&preq->list, &plo->ready_queue);
+		if (test_bit(PLOOP_S_WAIT_PROCESS, &plo->state))
+			wake_up_interruptible(&plo->waitq);
+		spin_unlock_irq(&plo->lock);
+	}
+}
diff --git a/drivers/block/ploop/push_backup.h b/drivers/block/ploop/push_backup.h
index 40d23f5..482e070 100644
--- a/drivers/block/ploop/push_backup.h
+++ b/drivers/block/ploop/push_backup.h
@@ -6,3 +6,8 @@ void ploop_pb_fini(struct ploop_pushbackup_desc *pbd);
 int ploop_pb_copy_cbt_to_user(struct ploop_pushbackup_desc *pbd, char *user_addr);
 unsigned long ploop_pb_stop(struct ploop_pushbackup_desc *pbd);
 int ploop_pb_check_uuid(struct ploop_pushbackup_desc *pbd, __u8 *uuid);
+
+int ploop_pb_get_pending(struct ploop_pushbackup_desc *pbd,
+			 cluster_t *clu_p, cluster_t *len_p, unsigned n_done);
+void ploop_pb_put_reported(struct ploop_pushbackup_desc *pbd,
+			   cluster_t clu, cluster_t len);
diff --git a/include/linux/ploop/ploop_if.h b/include/linux/ploop/ploop_if.h
index 83a68e5..81cc8d1 100644
--- a/include/linux/ploop/ploop_if.h
+++ b/include/linux/ploop/ploop_if.h
@@ -192,6 +192,26 @@ struct ploop_push_backup_init_ctl
 	__u64	cbt_mask_addr; /* page-aligned space for CBT mask */
 } __attribute__ ((aligned (8)));
 
+struct ploop_push_backup_ctl_extent
+{
+	__u32 clu;
+	__u32 len;
+} __attribute__ ((aligned (8)));
+
+/* ploop_push_backup_io_ctl.direction */
+enum {
+	PLOOP_READ = 0, /* wait for requests */
+	PLOOP_WRITE,    /* ACK requests */
+};
+
+struct ploop_push_backup_io_ctl
+{
+	__u8    cbt_uuid[16];
+	__u32	direction;
+	__u32	n_extents;
+	struct ploop_push_backup_ctl_extent extents[0];
+} __attribute__ ((aligned (8)));
+
 struct ploop_push_backup_stop_ctl
 {
 	__u8    cbt_uuid[16];
@@ -318,6 +338,9 @@ struct ploop_track_extent
 /* Start push backup */
 #define PLOOP_IOC_PUSH_BACKUP_INIT _IOR(PLOOPCTLTYPE, 29, struct ploop_push_backup_init_ctl)
 
+/* Wait for push backup out-of-order requests; or ACK them */
+#define PLOOP_IOC_PUSH_BACKUP_IO _IOR(PLOOPCTLTYPE, 30, struct ploop_push_backup_io_ctl)
+
 /* Stop push backup */
 #define PLOOP_IOC_PUSH_BACKUP_STOP _IOR(PLOOPCTLTYPE, 31, struct ploop_push_backup_stop_ctl)
 



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