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Commit 8618289c authored by Trond Myklebust's avatar Trond Myklebust Committed by Anna Schumaker
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NFSv4: Fix a sleep in atomic context in nfs4_callback_sequence() 



We must drop the lock before we can sleep in referring_call_exists().

Reported-by: default avatarJia-Ju Bai <baijiaju1990@gmail.com>
Fixes: 045d2a6d ("NFSv4.1: Delay callback processing...")
Cc: stable@vger.kernel.org # v4.9+
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent d0fbb1d8

fs/nfs/callback_proc.c

+10 −4
Original line number Diff line number Diff line
@@ -442,11 +442,14 @@ validate_seqid(const struct nfs4_slot_table *tbl, const struct nfs4_slot *slot, 
 * a match.  If the slot is in use and the sequence numbers match, the

 * client is still waiting for a response to the original request.

 */

static bool referring_call_exists(struct nfs_client *clp,

static int referring_call_exists(struct nfs_client *clp,

				  uint32_t nrclists,

				  struct referring_call_list *rclists)

				  struct referring_call_list *rclists,

				  spinlock_t *lock)

	__releases(lock)

	__acquires(lock)

{

	bool status = false;

	int status = 0;

	int i, j;

	struct nfs4_session *session;

	struct nfs4_slot_table *tbl;
@@ -469,8 +472,10 @@ static bool referring_call_exists(struct nfs_client *clp, 


		for (j = 0; j < rclist->rcl_nrefcalls; j++) {

			ref = &rclist->rcl_refcalls[j];

			spin_unlock(lock);

			status = nfs4_slot_wait_on_seqid(tbl, ref->rc_slotid,

					ref->rc_sequenceid, HZ >> 1) < 0;

			spin_lock(lock);

			if (status)

				goto out;

		}
@@ -547,7 +552,8 @@ __be32 nfs4_callback_sequence(void *argp, void *resp, 
	 * related callback was received before the response to the original

	 * call.

	 */

	if (referring_call_exists(clp, args->csa_nrclists, args->csa_rclists)) {

	if (referring_call_exists(clp, args->csa_nrclists, args->csa_rclists,

				&tbl->slot_tbl_lock) < 0) {

		status = htonl(NFS4ERR_DELAY);

		goto out_unlock;

	}