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From: Josef Bacik <josef@toxicpanda.com>
To: linux-btrfs@vger.kernel.org, kernel-team@fb.com
Subject: [PATCH 6/8] btrfs: clear BTRFS_ROOT_DEAD_RELOC_TREE before dropping the reloc root
Date: Wed,  4 Mar 2020 11:18:28 -0500	[thread overview]
Message-ID: <20200304161830.2360-7-josef@toxicpanda.com> (raw)
In-Reply-To: <20200304161830.2360-1-josef@toxicpanda.com>

We were doing the clear dance for the reloc root after doing the drop of
the reloc root, which means we have a giant window where we could miss
having BTRFS_ROOT_DEAD_RELOC_TREE unset and the reloc_root == NULL.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 fs/btrfs/relocation.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 53509c367eff..ceb90d152cdd 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2291,18 +2291,19 @@ static int clean_dirty_subvols(struct reloc_control *rc)
 
 			list_del_init(&root->reloc_dirty_list);
 			root->reloc_root = NULL;
-			if (reloc_root) {
-
-				ret2 = btrfs_drop_snapshot(reloc_root, NULL, 0, 1);
-				if (ret2 < 0 && !ret)
-					ret = ret2;
-			}
 			/*
 			 * Need barrier to ensure clear_bit() only happens after
 			 * root->reloc_root = NULL. Pairs with have_reloc_root.
 			 */
 			smp_wmb();
 			clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
+
+			if (reloc_root) {
+
+				ret2 = btrfs_drop_snapshot(reloc_root, NULL, 0, 1);
+				if (ret2 < 0 && !ret)
+					ret = ret2;
+			}
 			btrfs_put_root(root);
 		} else {
 			/* Orphan reloc tree, just clean it up */
-- 
2.24.1


  parent reply	other threads:[~2020-03-04 16:18 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-04 16:18 [PATCH 0/8][v2] relocation error handling fixes Josef Bacik
2020-03-04 16:18 ` [PATCH 1/8] btrfs: drop block from cache on error in relocation Josef Bacik
2020-03-05 11:37   ` Qu Wenruo
2020-03-04 16:18 ` [PATCH 2/8] btrfs: do not init a reloc root if we aren't relocating Josef Bacik
2020-03-04 18:44   ` Nikolay Borisov
2020-03-04 18:47     ` Josef Bacik
2020-03-05 11:24   ` Qu Wenruo
2020-03-04 16:18 ` [PATCH 3/8] btrfs: unset reloc control if we fail to recover Josef Bacik
2020-03-05 11:38   ` Qu Wenruo
2020-03-04 16:18 ` [PATCH 4/8] btrfs: free the reloc_control in a consistent way Josef Bacik
2020-03-05 11:39   ` Qu Wenruo
2020-03-13 15:18     ` David Sterba
2020-03-13 15:32       ` Josef Bacik
2020-03-14  0:13         ` Qu Wenruo
2020-03-04 16:18 ` [PATCH 5/8] btrfs: run clean_dirty_subvols if we fail to start a trans Josef Bacik
2020-03-05 11:40   ` Qu Wenruo
2020-03-05 17:46   ` David Sterba
2020-03-04 16:18 ` Josef Bacik [this message]
2020-03-05 11:41   ` [PATCH 6/8] btrfs: clear BTRFS_ROOT_DEAD_RELOC_TREE before dropping the reloc root Qu Wenruo
2020-03-05 13:54     ` Josef Bacik
2020-03-04 16:18 ` [PATCH 7/8] btrfs: hold a ref on the root->reloc_root Josef Bacik
2020-03-04 16:18 ` [PATCH 8/8] btrfs: remove a BUG_ON() from merge_reloc_roots() Josef Bacik
2020-03-13 14:35 ` [PATCH 0/8][v2] relocation error handling fixes David Sterba
2020-03-13 15:44 [PATCH 0/8][v3] " Josef Bacik
2020-03-13 15:44 ` [PATCH 6/8] btrfs: clear BTRFS_ROOT_DEAD_RELOC_TREE before dropping the reloc root Josef Bacik

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