diff mbox series

[3/3] tools/oxenstored: mkdir conflicts were sometimes missed

Message ID 20210203173549.21159-4-andrew.cooper3@citrix.com (mailing list archive)
State New
Headers show
Series tools/oxenstored bugfixes | expand

Commit Message

Andrew Cooper Feb. 3, 2021, 5:35 p.m. UTC
From: Edwin Török <edvin.torok@citrix.com>

Due to how set_write_lowpath was used here it didn't detect create/delete
conflicts.  When we create an entry we must mark our parent as modified
(this is what creating a new node via write does).

Otherwise we can have 2 transactions one creating, and another deleting a node
both succeeding depending on timing.  Or one transaction reading an entry,
concluding it doesn't exist, do some other work based on that information and
successfully commit even if another transaction creates the node via mkdir
meanwhile.

Signed-off-by: Edwin Török <edvin.torok@citrix.com>
---
CC: Christian Lindig <christian.lindig@citrix.com>
CC: Ian Jackson <iwj@xenproject.org>
CC: Wei Liu <wl@xen.org>
---
 tools/ocaml/xenstored/transaction.ml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Christian Lindig Feb. 4, 2021, 10:52 a.m. UTC | #1
Acked-by: Christian Lindig <christian.lindig@citrix.com>
diff mbox series

Patch

diff --git a/tools/ocaml/xenstored/transaction.ml b/tools/ocaml/xenstored/transaction.ml
index 25bc8c3b4a..17b1bdf2ea 100644
--- a/tools/ocaml/xenstored/transaction.ml
+++ b/tools/ocaml/xenstored/transaction.ml
@@ -165,7 +165,7 @@  let write t perm path value =
 
 let mkdir ?(with_watch=true) t perm path =
 	Store.mkdir t.store perm path;
-	set_write_lowpath t path;
+	set_write_lowpath t (Store.Path.get_parent path);
 	if with_watch then
 		add_wop t Xenbus.Xb.Op.Mkdir path