[libvirt] [PATCH 1/2] virSecurityManagerMetadataLock: Expand the comment on deadlocks

Document why we need to sort paths while it's still fresh in my memory. Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/security/security_manager.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/src/security/security_manager.c b/src/security/security_manager.c index c205c3bf17..ade2c96141 100644 --- a/src/security/security_manager.c +++ b/src/security/security_manager.c @@ -1289,7 +1289,12 @@ virSecurityManagerMetadataLock(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED, if (VIR_ALLOC_N(fds, npaths) < 0) return NULL; - /* Sort paths to lock in order to avoid deadlocks. */ + /* Sort paths to lock in order to avoid deadlocks with other + * processes. For instance, if one process wants to lock + * paths A B and there's another that is trying to lock them + * in reversed order a deadlock might occur. But if we sort + * the paths alphabetically then both processes will try lock + * paths in the same order and thus no deadlock can occur. */ qsort(paths, npaths, sizeof(*paths), cmpstringp); for (i = 0; i < npaths; i++) { -- 2.21.0