From: Jeff Layton jlayton@kernel.org
[ Upstream commit e0aa651068bfd520afcd357af8ecd2de005fc83d ]
We had a report of this:
BUG: sleeping function called from invalid context at fs/nfsd/filecache.c:440
...with a stack trace showing nfsd_file_put being called from nfs4_show_open. This code has always tried to call fput while holding a spinlock, but we recently changed this to use the filecache, and that started triggering the might_sleep() in nfsd_file_put.
states_start takes and holds the cl_lock while iterating over the client's states, and we can't sleep with that held.
Have the various nfs4_show_* functions instead hold the fi_lock instead of taking a nfsd_file reference.
Fixes: 78599c42ae3c ("nfsd4: add file to display list of client's opens") Link: https://bugzilla.redhat.com/show_bug.cgi?id=2138357 Reported-by: Zhi Li yieli@redhat.com Signed-off-by: Jeff Layton jlayton@kernel.org Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfsd/nfs4state.c | 51 +++++++++++++++++++++++++++++---------------- 1 file changed, 33 insertions(+), 18 deletions(-)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 7b763f146b62..c062728034ad 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -627,15 +627,26 @@ find_any_file(struct nfs4_file *f) return ret; }
-static struct nfsd_file *find_deleg_file(struct nfs4_file *f) +static struct nfsd_file *find_any_file_locked(struct nfs4_file *f) { - struct nfsd_file *ret = NULL; + lockdep_assert_held(&f->fi_lock); + + if (f->fi_fds[O_RDWR]) + return f->fi_fds[O_RDWR]; + if (f->fi_fds[O_WRONLY]) + return f->fi_fds[O_WRONLY]; + if (f->fi_fds[O_RDONLY]) + return f->fi_fds[O_RDONLY]; + return NULL; +} + +static struct nfsd_file *find_deleg_file_locked(struct nfs4_file *f) +{ + lockdep_assert_held(&f->fi_lock);
- 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; + return f->fi_deleg_file; + return NULL; }
static atomic_long_t num_delegations; @@ -2501,9 +2512,11 @@ static int nfs4_show_open(struct seq_file *s, struct nfs4_stid *st) ols = openlockstateid(st); oo = ols->st_stateowner; nf = st->sc_file; - file = find_any_file(nf); + + spin_lock(&nf->fi_lock); + file = find_any_file_locked(nf); if (!file) - return 0; + goto out;
seq_printf(s, "- "); nfs4_show_stateid(s, &st->sc_stateid); @@ -2525,8 +2538,8 @@ static int nfs4_show_open(struct seq_file *s, struct nfs4_stid *st) seq_printf(s, ", "); nfs4_show_owner(s, oo); seq_printf(s, " }\n"); - nfsd_file_put(file); - +out: + spin_unlock(&nf->fi_lock); return 0; }
@@ -2540,9 +2553,10 @@ static int nfs4_show_lock(struct seq_file *s, struct nfs4_stid *st) ols = openlockstateid(st); oo = ols->st_stateowner; nf = st->sc_file; - file = find_any_file(nf); + spin_lock(&nf->fi_lock); + file = find_any_file_locked(nf); if (!file) - return 0; + goto out;
seq_printf(s, "- "); nfs4_show_stateid(s, &st->sc_stateid); @@ -2562,8 +2576,8 @@ static int nfs4_show_lock(struct seq_file *s, struct nfs4_stid *st) seq_printf(s, ", "); nfs4_show_owner(s, oo); seq_printf(s, " }\n"); - nfsd_file_put(file); - +out: + spin_unlock(&nf->fi_lock); return 0; }
@@ -2575,9 +2589,10 @@ static int nfs4_show_deleg(struct seq_file *s, struct nfs4_stid *st)
ds = delegstateid(st); nf = st->sc_file; - file = find_deleg_file(nf); + spin_lock(&nf->fi_lock); + file = find_deleg_file_locked(nf); if (!file) - return 0; + goto out;
seq_printf(s, "- "); nfs4_show_stateid(s, &st->sc_stateid); @@ -2593,8 +2608,8 @@ static int nfs4_show_deleg(struct seq_file *s, struct nfs4_stid *st) seq_printf(s, ", "); nfs4_show_fname(s, file); seq_printf(s, " }\n"); - nfsd_file_put(file); - +out: + spin_unlock(&nf->fi_lock); return 0; }