From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Naohiro Aota <naohiro.aota@wdc.com>,
        Johannes Thumshirn <johannes.thumshirn@wdc.com>,
        David Sterba <dsterba@suse.com>
Subject: [PATCH 5.15 09/20] btrfs: check for relocation inodes on zoned btrfs in should_nocow
Date:   Fri, 19 Nov 2021 18:39:27 +0100
Message-Id: <20211119171444.959705952@linuxfoundation.org>
In-Reply-To: <20211119171444.640508836@linuxfoundation.org>
References: <20211119171444.640508836@linuxfoundation.org>
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From: Johannes Thumshirn <johannes.thumshirn@wdc.com>

commit 2adada886b26e998b5a624e72f0834ebfdc54cc7 upstream

Prepare for allowing preallocation for relocation inodes.

Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/btrfs/inode.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1945,7 +1945,15 @@ int btrfs_run_delalloc_range(struct btrf
 	const bool zoned = btrfs_is_zoned(inode->root->fs_info);
 
 	if (should_nocow(inode, start, end)) {
-		ASSERT(!zoned);
+		/*
+		 * Normally on a zoned device we're only doing COW writes, but
+		 * in case of relocation on a zoned filesystem we have taken
+		 * precaution, that we're only writing sequentially. It's safe
+		 * to use run_delalloc_nocow() here, like for  regular
+		 * preallocated inodes.
+		 */
+		ASSERT(!zoned ||
+		       (zoned && btrfs_is_data_reloc_root(inode->root)));
 		ret = run_delalloc_nocow(inode, locked_page, start, end,
 					 page_started, nr_written);
 	} else if (!inode_can_compress(inode) ||