The commit is pushed to "branch-rh7-3.10.0-327.18.2.vz7.14.x-ovz" and will
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-327.18.2.vz7.14.24
------>
commit 91a74e3b91ab9aa0d4be64b01f86a14c36b3279e
Author: Maxim Patlasov <[email protected]>
Date: Wed Jul 13 20:52:28 2016 +0400
ploop: add PLOOP_IOC_FREEZE and PLOOP_IOC_THAW ioctls
The ioctls simply freeze and thaw ploop bdev.
If no fs is mounted over ploop bdev being frozen, then the freeze ioctl
just increments bd_fsfreeze_count, which prevents the ploop from being
mounted until it is thawed.
https://jira.sw.ru/browse/PSBM-49091
Caveats:
1) No nested freeze: many PLOOP_IOC_FREEZE ioctls have the same effect as
one.
2) The same for thaw.
[vdavydov@: allow to freeze unmounted ploop]
Signed-off-by: Maxim Patlasov <[email protected]>
Signed-off-by: Vladimir Davydov <[email protected]>
Cc: Pavel Borzenkov <[email protected]>
---
drivers/block/ploop/dev.c | 39 +++++++++++++++++++++++++++++++++++++++
include/linux/ploop/ploop.h | 2 ++
include/linux/ploop/ploop_if.h | 6 ++++++
3 files changed, 47 insertions(+)
diff --git a/drivers/block/ploop/dev.c b/drivers/block/ploop/dev.c
index e5f010b9aeba..d52975eaaa36 100644
--- a/drivers/block/ploop/dev.c
+++ b/drivers/block/ploop/dev.c
@@ -4815,6 +4815,39 @@ static int ploop_push_backup_stop(struct ploop_device
*plo, unsigned long arg)
return copy_to_user((void*)arg, &ctl, sizeof(ctl));
}
+static int ploop_freeze(struct ploop_device *plo, struct block_device *bdev)
+{
+ struct super_block *sb = plo->sb;
+
+ if (test_bit(PLOOP_S_FROZEN, &plo->state))
+ return 0;
+
+ sb = freeze_bdev(bdev);
+ if (sb && IS_ERR(sb))
+ return PTR_ERR(sb);
+
+ plo->sb = sb;
+ set_bit(PLOOP_S_FROZEN, &plo->state);
+ return 0;
+}
+
+static int ploop_thaw(struct ploop_device *plo, struct block_device *bdev)
+{
+ struct super_block *sb = plo->sb;
+ int err;
+
+ if (!test_bit(PLOOP_S_FROZEN, &plo->state))
+ return 0;
+
+ err = thaw_bdev(bdev, sb);
+ if (!err) {
+ plo->sb = NULL;
+ clear_bit(PLOOP_S_FROZEN, &plo->state);
+ }
+
+ return err;
+}
+
static int ploop_ioctl(struct block_device *bdev, fmode_t fmode, unsigned int
cmd,
unsigned long arg)
{
@@ -4928,6 +4961,12 @@ static int ploop_ioctl(struct block_device *bdev,
fmode_t fmode, unsigned int cm
case PLOOP_IOC_PUSH_BACKUP_STOP:
err = ploop_push_backup_stop(plo, arg);
break;
+ case PLOOP_IOC_FREEZE:
+ err = ploop_freeze(plo, bdev);
+ break;
+ case PLOOP_IOC_THAW:
+ err = ploop_thaw(plo, bdev);
+ break;
default:
err = -EINVAL;
}
diff --git a/include/linux/ploop/ploop.h b/include/linux/ploop/ploop.h
index deee8a78cc96..7864edf17f19 100644
--- a/include/linux/ploop/ploop.h
+++ b/include/linux/ploop/ploop.h
@@ -61,6 +61,7 @@ enum {
(for minor mgmt only) */
PLOOP_S_ONCE, /* An event (e.g. printk once) happened */
PLOOP_S_PUSH_BACKUP, /* Push_backup is in progress */
+ PLOOP_S_FROZEN /* Frozen PLOOP_IOC_FREEZE */
};
struct ploop_snapdata
@@ -409,6 +410,7 @@ struct ploop_device
struct block_device *bdev;
struct request_queue *queue;
struct task_struct *thread;
+ struct super_block *sb;
struct rb_node link;
/* someone who wants to quiesce state-machine waits
diff --git a/include/linux/ploop/ploop_if.h b/include/linux/ploop/ploop_if.h
index a098ca9d0ef0..302ace984a5a 100644
--- a/include/linux/ploop/ploop_if.h
+++ b/include/linux/ploop/ploop_if.h
@@ -352,6 +352,12 @@ struct ploop_track_extent
/* Stop push backup */
#define PLOOP_IOC_PUSH_BACKUP_STOP _IOR(PLOOPCTLTYPE, 31, struct
ploop_push_backup_stop_ctl)
+/* Freeze FS mounted over ploop */
+#define PLOOP_IOC_FREEZE _IO(PLOOPCTLTYPE, 32)
+
+/* Unfreeze FS mounted over ploop */
+#define PLOOP_IOC_THAW _IO(PLOOPCTLTYPE, 33)
+
/* Events exposed via /sys/block/ploopN/pstate/event */
#define PLOOP_EVENT_ABORTED 1
#define PLOOP_EVENT_STOPPED 2
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