pve-kernel-lowlatency-qoup/patches/kernel/0008-Revert-block-remove-the-ERESTARTSYS-handling-in-blkd.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Thomas Lamprecht <t.lamprecht@proxmox.com>
Date: Tue, 9 Nov 2021 12:01:12 +0100
Subject: [PATCH] Revert "block: remove the -ERESTARTSYS handling in
 blkdev_get_by_dev"

This reverts commit a8ed1a0607cfa5478ff6009539f44790c4d0956d.

It breaks ZFS sometimes:
https://github.com/openzfs/zfs/issues/12301#issuecomment-873303739

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
 block/bdev.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/block/bdev.c b/block/bdev.c
index 485a258b0ab3..f93165f05987 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -800,6 +800,10 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 	if (ret)
 		return ERR_PTR(ret);
 
+	/*
+	 * If we lost a race with 'disk' being deleted, try again.  See md.c.
+	 */
+retry:
 	bdev = blkdev_get_no_open(dev);
 	if (!bdev)
 		return ERR_PTR(-ENXIO);
@@ -852,6 +856,8 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 	disk_unblock_events(disk);
 put_blkdev:
 	blkdev_put_no_open(bdev);
+	if (ret == -ERESTARTSYS)
+		goto retry;
 	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL(blkdev_get_by_dev);