libceph: enable fallback to ceph_msg_new() in ceph_msgpool_get()

ceph_msgpool_get() can fall back to ceph_msg_new() when it is asked for
a message whose front portion is larger than pool->front_len.  However
the caller always passes 0, effectively disabling that code path.  The
allocation goes to the message pool and returns a message with a front
that is smaller than requested, setting us up for a crash.

One example of this is a directory with a large number of snapshots.
If its snap context doesn't fit, we oops in encode_request_partial().

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This commit is contained in:
Ilya Dryomov 2018-10-11 17:04:33 +02:00
parent 61d2f85504
commit 3b83f60da6
2 changed files with 3 additions and 3 deletions

View File

@ -61,7 +61,7 @@ struct ceph_msg *ceph_msgpool_get(struct ceph_msgpool *pool,
if (front_len > pool->front_len) {
dout("msgpool_get %s need front %d, pool size is %d\n",
pool->name, front_len, pool->front_len);
WARN_ON(1);
WARN_ON_ONCE(1);
/* try to alloc a fresh message */
return ceph_msg_new(pool->type, front_len, GFP_NOFS, false);

View File

@ -641,7 +641,7 @@ int ceph_osdc_alloc_messages(struct ceph_osd_request *req, gfp_t gfp)
msg_size += 4 + 8; /* retry_attempt, features */
if (req->r_mempool)
msg = ceph_msgpool_get(&osdc->msgpool_op, 0);
msg = ceph_msgpool_get(&osdc->msgpool_op, msg_size);
else
msg = ceph_msg_new(CEPH_MSG_OSD_OP, msg_size, gfp, true);
if (!msg)
@ -656,7 +656,7 @@ int ceph_osdc_alloc_messages(struct ceph_osd_request *req, gfp_t gfp)
msg_size += req->r_num_ops * sizeof(struct ceph_osd_op);
if (req->r_mempool)
msg = ceph_msgpool_get(&osdc->msgpool_op_reply, 0);
msg = ceph_msgpool_get(&osdc->msgpool_op_reply, msg_size);
else
msg = ceph_msg_new(CEPH_MSG_OSD_OPREPLY, msg_size, gfp, true);
if (!msg)