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NFSv4.1: Fix Oopsable condition in server callback races

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The slot table hasn't been an array since v3.7. Ensure that we
use nfs4_lookup_slot() to access the slot correctly.

Fixes: 87dda67e73 ("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+
This commit is contained in:
Trond Myklebust 2016-08-27 23:44:04 -04:00
parent 16590a2281
commit e09c978aae
3 changed files with 35 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
fs/nfs/callback_proc.c
View File

@ -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;
}

33
fs/nfs/nfs4session.c
View File

@ -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
*

1
fs/nfs/nfs4session.h
View File

@ -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);