From: Jeff Layton jlayton@kernel.org
commit fb24771faf72a2fd62b3b6287af3c610c3ec9cf1 upstream.
It's possible for a request to invalidate a fscache_cookie will come in while we're already processing an invalidation. If that happens we currently take an extra access reference that will leak. Only call __fscache_begin_cookie_access if the FSCACHE_COOKIE_DO_INVALIDATE bit was previously clear.
Also, ensure that we attempt to clear the bit when the cookie is "FAILED" and put the reference to avoid an access leak.
Fixes: 85e4ea1049c7 ("fscache: Fix invalidation/lookup race") Suggested-by: David Howells dhowells@redhat.com Signed-off-by: Jeff Layton jlayton@kernel.org Signed-off-by: David Howells dhowells@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/fscache/cookie.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c index 74920826d8f6..26a6d395737a 100644 --- a/fs/fscache/cookie.c +++ b/fs/fscache/cookie.c @@ -739,6 +739,9 @@ static void fscache_cookie_state_machine(struct fscache_cookie *cookie) fallthrough;
case FSCACHE_COOKIE_STATE_FAILED: + if (test_and_clear_bit(FSCACHE_COOKIE_DO_INVALIDATE, &cookie->flags)) + fscache_end_cookie_access(cookie, fscache_access_invalidate_cookie_end); + if (atomic_read(&cookie->n_accesses) != 0) break; if (test_bit(FSCACHE_COOKIE_DO_RELINQUISH, &cookie->flags)) { @@ -1063,8 +1066,8 @@ void __fscache_invalidate(struct fscache_cookie *cookie, return;
case FSCACHE_COOKIE_STATE_LOOKING_UP: - __fscache_begin_cookie_access(cookie, fscache_access_invalidate_cookie); - set_bit(FSCACHE_COOKIE_DO_INVALIDATE, &cookie->flags); + if (!test_and_set_bit(FSCACHE_COOKIE_DO_INVALIDATE, &cookie->flags)) + __fscache_begin_cookie_access(cookie, fscache_access_invalidate_cookie); fallthrough; case FSCACHE_COOKIE_STATE_CREATING: spin_unlock(&cookie->lock);