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authorTrond Myklebust <trond.myklebust@primarydata.com>2016-08-27 23:44:04 -0400
committerTrond Myklebust <trond.myklebust@primarydata.com>2016-08-28 14:23:22 -0400
commite09c978aae5bedfdb379be80363b024b7d82638b (patch)
treed218fe2842cef66c0d33648f1f12163a61f70a62 /fs/nfs
parent16590a228109e2f318d2cc6466221134cfab723a (diff)
NFSv4.1: Fix Oopsable condition in server callback races
The slot table hasn't been an array since v3.7. Ensure that we use nfs4_lookup_slot() to access the slot correctly. Fixes: 87dda67e7386 ("NFSv4.1: Allow SEQUENCE to resize the slot table...") Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Cc: stable@vger.kernel.org # v3.8+
Diffstat (limited to 'fs/nfs')
-rw-r--r--fs/nfs/callback_proc.c5
-rw-r--r--fs/nfs/nfs4session.c33
-rw-r--r--fs/nfs/nfs4session.h1
3 files changed, 35 insertions, 4 deletions
diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index c92a75e066a6..a4cf6d2c14a4 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -454,11 +454,8 @@ static bool referring_call_exists(struct nfs_client *clp,
((u32 *)&rclist->rcl_sessionid.data)[3],
ref->rc_sequenceid, ref->rc_slotid);
- spin_lock(&tbl->slot_tbl_lock);
- status = (test_bit(ref->rc_slotid, tbl->used_slots) &&
- tbl->slots[ref->rc_slotid].seq_nr ==
+ status = nfs4_slot_seqid_in_use(tbl, ref->rc_slotid,
ref->rc_sequenceid);
- spin_unlock(&tbl->slot_tbl_lock);
if (status)
goto out;
}
diff --git a/fs/nfs/nfs4session.c b/fs/nfs/nfs4session.c
index 332d06e64fa9..c1f4c208f38a 100644
--- a/fs/nfs/nfs4session.c
+++ b/fs/nfs/nfs4session.c
@@ -172,6 +172,39 @@ struct nfs4_slot *nfs4_lookup_slot(struct nfs4_slot_table *tbl, u32 slotid)
return ERR_PTR(-E2BIG);
}
+static int nfs4_slot_get_seqid(struct nfs4_slot_table *tbl, u32 slotid,
+ u32 *seq_nr)
+ __must_hold(&tbl->slot_tbl_lock)
+{
+ struct nfs4_slot *slot;
+
+ slot = nfs4_lookup_slot(tbl, slotid);
+ if (IS_ERR(slot))
+ return PTR_ERR(slot);
+ *seq_nr = slot->seq_nr;
+ return 0;
+}
+
+/*
+ * nfs4_slot_seqid_in_use - test if a slot sequence id is still in use
+ *
+ * Given a slot table, slot id and sequence number, determine if the
+ * RPC call in question is still in flight. This function is mainly
+ * intended for use by the callback channel.
+ */
+bool nfs4_slot_seqid_in_use(struct nfs4_slot_table *tbl, u32 slotid, u32 seq_nr)
+{
+ u32 cur_seq;
+ bool ret = false;
+
+ spin_lock(&tbl->slot_tbl_lock);
+ if (nfs4_slot_get_seqid(tbl, slotid, &cur_seq) == 0 &&
+ cur_seq == seq_nr && test_bit(slotid, tbl->used_slots))
+ ret = true;
+ spin_unlock(&tbl->slot_tbl_lock);
+ return ret;
+}
+
/*
* nfs4_alloc_slot - efficiently look for a free slot
*
diff --git a/fs/nfs/nfs4session.h b/fs/nfs/nfs4session.h
index 5b51298d1d03..33cace62b50b 100644
--- a/fs/nfs/nfs4session.h
+++ b/fs/nfs/nfs4session.h
@@ -78,6 +78,7 @@ extern int nfs4_setup_slot_table(struct nfs4_slot_table *tbl,
extern void nfs4_shutdown_slot_table(struct nfs4_slot_table *tbl);
extern struct nfs4_slot *nfs4_alloc_slot(struct nfs4_slot_table *tbl);
extern struct nfs4_slot *nfs4_lookup_slot(struct nfs4_slot_table *tbl, u32 slotid);
+extern bool nfs4_slot_seqid_in_use(struct nfs4_slot_table *tbl, u32 slotid, u32 seq_nr);
extern bool nfs4_try_to_lock_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot);
extern void nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot);
extern void nfs4_slot_tbl_drain_complete(struct nfs4_slot_table *tbl);