btrfs: don't get an EINTR during drop_snapshot for reloc

This was partially fixed by f3e3d9c ("btrfs: avoid possible signal interruption of btrfs_drop_snapshot() on relocation tree"), however it missed a spot when we restart a trans handle because we need to end the transaction. The fix is the same, simply use btrfs_join_transaction() instead of btrfs_start_transaction() when deleting reloc roots. Fixes: f3e3d9c ("btrfs: avoid possible signal interruption of btrfs_drop_snapshot() on relocation tree") CC: [email protected] # 5.4+ Signed-off-by: Josef Bacik <[email protected]> Reviewed-by: David Sterba <[email protected]> Signed-off-by: David Sterba <[email protected]>
multipath-tcp · Jan 18, 2021 · 18d3bff · 18d3bff
1 parent 518837e
commit 18d3bff
Showing 1 changed file with 9 additions and 1 deletion.
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
@@ -5549,7 +5549,15 @@ int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc)
 				goto out_free;
 			}
 
-			trans = btrfs_start_transaction(tree_root, 0);
+		       /*
+			* Use join to avoid potential EINTR from transaction
+			* start. See wait_reserve_ticket and the whole
+			* reservation callchain.
+			*/
+			if (for_reloc)
+				trans = btrfs_join_transaction(tree_root);
+			else
+				trans = btrfs_start_transaction(tree_root, 0);
 			if (IS_ERR(trans)) {
 				err = PTR_ERR(trans);
 				goto out_free;