From fa4b1a404e12d3b883c86d8ea13d8c1203addce0 Mon Sep 17 00:00:00 2001 From: Alexander Motin Date: Fri, 10 May 2024 15:35:20 -0400 Subject: [PATCH] ZAP: Fix leaf references on zap_expand_leaf() errors Depending on kind of error zap_expand_leaf() may return with or without valid leaf reference held. Make sure it returns NULL if due to error it has no leaf to return. Make its callers to check the returned leaf pointer, and release the leaf if it is not NULL. Reviewed-by: Brian Behlendorf Signed-off-by: Alexander Motin Sponsored by: iXsystems, Inc. Closes #12366 Closes #16159 --- module/zfs/zap.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/module/zfs/zap.c b/module/zfs/zap.c index da86defb44..e8e02bf0c2 100644 --- a/module/zfs/zap.c +++ b/module/zfs/zap.c @@ -635,6 +635,7 @@ zap_expand_leaf(zap_name_t *zn, zap_leaf_t *l, uint64_t object = zap->zap_object; zap_put_leaf(l); + *lp = l = NULL; zap_unlockdir(zap, tag); err = zap_lockdir(os, object, tx, RW_WRITER, FALSE, FALSE, tag, &zn->zn_zap); @@ -844,21 +845,17 @@ retry: } else if (err == EAGAIN) { err = zap_expand_leaf(zn, l, tag, tx, &l); zap = zn->zn_zap; /* zap_expand_leaf() may change zap */ - if (err == 0) { + if (err == 0) goto retry; - } else if (err == ENOSPC) { - /* - * If we failed to expand the leaf, then bailout - * as there is no point trying - * zap_put_leaf_maybe_grow_ptrtbl(). - */ - return (err); - } } out: - if (zap != NULL) - zap_put_leaf_maybe_grow_ptrtbl(zn, l, tag, tx); + if (l != NULL) { + if (err == ENOSPC) + zap_put_leaf(l); + else + zap_put_leaf_maybe_grow_ptrtbl(zn, l, tag, tx); + } return (err); } @@ -915,8 +912,12 @@ retry: goto retry; } - if (zap != NULL) - zap_put_leaf_maybe_grow_ptrtbl(zn, l, tag, tx); + if (l != NULL) { + if (err == ENOSPC) + zap_put_leaf(l); + else + zap_put_leaf_maybe_grow_ptrtbl(zn, l, tag, tx); + } return (err); }