From: J. Bruce Fields bfields@redhat.com
[ Upstream commit 9affa435817711861d774f5626c393c80f16d044 ]
We hold the cl_lock here, and that's enough to keep stateid's from going away, but it's not enough to prevent the files they point to from going away. Take fi_lock and a reference and check for NULL, as we do in other code.
Reported-by: NeilBrown neilb@suse.de Fixes: 78599c42ae3c ("nfsd4: add file to display list of client's opens") Reviewed-by: NeilBrown neilb@suse.de Signed-off-by: J. Bruce Fields bfields@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfsd/nfs4state.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 9af9b673f2923..68cf116607645 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -506,6 +506,17 @@ find_any_file(struct nfs4_file *f) return ret; }
+static struct nfsd_file *find_deleg_file(struct nfs4_file *f) +{ + struct nfsd_file *ret = NULL; + + spin_lock(&f->fi_lock); + if (f->fi_deleg_file) + ret = nfsd_file_get(f->fi_deleg_file); + spin_unlock(&f->fi_lock); + return ret; +} + static atomic_long_t num_delegations; unsigned long max_delegations;
@@ -2378,6 +2389,8 @@ static int nfs4_show_open(struct seq_file *s, struct nfs4_stid *st) oo = ols->st_stateowner; nf = st->sc_file; file = find_any_file(nf); + if (!file) + return 0;
seq_printf(s, "- 0x%16phN: { type: open, ", &st->sc_stateid);
@@ -2411,6 +2424,8 @@ static int nfs4_show_lock(struct seq_file *s, struct nfs4_stid *st) oo = ols->st_stateowner; nf = st->sc_file; file = find_any_file(nf); + if (!file) + return 0;
seq_printf(s, "- 0x%16phN: { type: lock, ", &st->sc_stateid);
@@ -2439,7 +2454,9 @@ static int nfs4_show_deleg(struct seq_file *s, struct nfs4_stid *st)
ds = delegstateid(st); nf = st->sc_file; - file = nf->fi_deleg_file; + file = find_deleg_file(nf); + if (!file) + return 0;
seq_printf(s, "- 0x%16phN: { type: deleg, ", &st->sc_stateid);
@@ -2451,6 +2468,7 @@ static int nfs4_show_deleg(struct seq_file *s, struct nfs4_stid *st)
nfs4_show_superblock(s, file); seq_printf(s, " }\n"); + nfsd_file_put(file);
return 0; }