[Devel] [PATCH RHEL7 COMMIT] ploop: Disable discard on ioctl(PLOOP_IOC_FREEZE)

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-1127.10.1.vz7.162.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-1127.10.1.vz7.162.1
------>
commit d7b00695468faa7e4e1a5b40e0f972c0f6c7ccaf
Author: Kirill Tkhai <ktkhai at virtuozzo.com>
Date:   Fri Jun 5 18:43:38 2020 +0300

    ploop: Disable discard on ioctl(PLOOP_IOC_FREEZE)
    
    freeze_bdev() does not affect on discard sent from FITRIM.
    Prohibit it too.
    
    In scope of https://jira.sw.ru/browse/PSBM-104462
    
    Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
---
 drivers/block/ploop/dev.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/block/ploop/dev.c b/drivers/block/ploop/dev.c
index 201315e973b70..6ee315b54fc9b 100644
--- a/drivers/block/ploop/dev.c
+++ b/drivers/block/ploop/dev.c
@@ -5283,6 +5283,7 @@ static int ploop_push_backup_stop(struct ploop_device *plo, unsigned long arg)
 static int ploop_freeze(struct ploop_device *plo, struct block_device *bdev)
 {
 	struct super_block *sb;
+	int ret;
 
 	if (!test_bit(PLOOP_S_RUNNING, &plo->state))
 		return -EINVAL;
@@ -5293,6 +5294,14 @@ static int ploop_freeze(struct ploop_device *plo, struct block_device *bdev)
 	if (plo->freeze_state == PLOOP_F_THAWING)
 		return -EBUSY;
 
+	/*
+	 * Disable discard, since below freeze_bdev()
+	 * does not affect FITRIM.
+	 */
+	ret = disable_and_wait_discard(plo);
+	if (ret)
+		return ret;
+
 	if (plo->dm_crypt_bdev)
 		bdev = plo->dm_crypt_bdev;
 
@@ -5300,6 +5309,7 @@ static int ploop_freeze(struct ploop_device *plo, struct block_device *bdev)
 	sb = freeze_bdev(bdev);
 	if (sb && IS_ERR(sb)) {
 		bdput(bdev);
+		enable_discard(plo);
 		return PTR_ERR(sb);
 	}
 
@@ -5337,10 +5347,12 @@ static int ploop_thaw(struct ploop_device *plo)
 
 	BUG_ON(plo->freeze_state != PLOOP_F_THAWING);
 
-	if (!err)
+	if (!err) {
+		enable_discard(plo);
 		plo->freeze_state = PLOOP_F_NORMAL;
-	else
+	} else {
 		plo->freeze_state = PLOOP_F_FROZEN;
+	}
 
 	return err;
 }