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authorJeff Layton <jlayton@kernel.org>2022-08-05 13:42:45 +0300
committerDavid Howells <dhowells@redhat.com>2022-08-09 16:13:55 +0300
commitfb24771faf72a2fd62b3b6287af3c610c3ec9cf1 (patch)
treeca92f6258605d877ac7155f86ca95d1e0499f3cd /fs
parent3d7cb6b04c3f3115719235cc6866b10326de34cd (diff)
downloadlinux-fb24771faf72a2fd62b3b6287af3c610c3ec9cf1.tar.xz
fscache: don't leak cookie access refs if invalidation is in progress or failed
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>
Diffstat (limited to 'fs')
-rw-r--r--fs/fscache/cookie.c7
1 files 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 @@ again_locked:
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);