On Mon, Feb 6, 2017 at 5:36 PM, Jeff Layton <jlayton@xxxxxxxxxx> wrote:
> On Mon, 2017-02-06 at 17:27 +0100, Ilya Dryomov wrote:
>> On Mon, Feb 6, 2017 at 4:49 PM, Jeff Layton <jlayton@xxxxxxxxxx> wrote:
>> > On Mon, 2017-02-06 at 15:09 +0100, Ilya Dryomov wrote:
>> >
>> > [...]
>> >
>> > > > diff --git a/include/linux/ceph/rados.h b/include/linux/ceph/rados.h
>> > > > index 5c0da61cb763..def43570a85a 100644
>> > > > --- a/include/linux/ceph/rados.h
>> > > > +++ b/include/linux/ceph/rados.h
>> > > > @@ -401,6 +401,7 @@ enum {
>> > > > CEPH_OSD_FLAG_KNOWN_REDIR = 0x400000, /* redirect bit is authoritative */
>> > > > CEPH_OSD_FLAG_FULL_TRY = 0x800000, /* try op despite full flag */
>> > > > CEPH_OSD_FLAG_FULL_FORCE = 0x1000000, /* force op despite full flag */
>> > > > + CEPH_OSD_FLAG_FULL_CANCEL = 0x2000000, /* cancel operation on full flag */
>> > >
>> > > Is this a new flag? This is the wire protocol and I don't see it in
>> > > ceph.git.
>> > >
>> > > I'll look at epoch_barrier and callback stuff later.
>> > >
>> > > Thanks,
>> > >
>> > > Ilya
>> >
>> > Here's a respun version of the last patch in the set. This should avoid
>> > adding an on the wire flag. I just added a new bool and changed the
>> > code to set and look at that to indicate the desire for an immediate
>> > error return in this case. Compiles but is otherwise untested. I'll give
>> > it a go in a bit.
>> >
>> > -----------------------------8<------------------------------
>> >
>> > libceph: allow requests to return immediately on full
>> > conditions if caller wishes
>> >
>> > Right now, cephfs will cancel any in-flight OSD write operations when a
>> > new map comes in that shows the OSD or pool as full, but nothing
>> > prevents new requests from stalling out after that point.
>> >
>> > If the caller knows that it will want an immediate error return instead
>> > of blocking on a full or at-quota error condition then allow it to set a
>> > flag to request that behavior. Cephfs write requests will always set
>> > that flag.
>> >
>> > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
>> > ---
>> > fs/ceph/addr.c | 4 ++++
>> > fs/ceph/file.c | 4 ++++
>> > include/linux/ceph/osd_client.h | 1 +
>> > net/ceph/osd_client.c | 6 ++++++
>> > 4 files changed, 15 insertions(+)
>> >
>> > diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
>> > index 4547bbf80e4f..ef9c9bae7460 100644
>> > --- a/fs/ceph/addr.c
>> > +++ b/fs/ceph/addr.c
>> > @@ -1040,6 +1040,7 @@ static int ceph_writepages_start(struct address_space *mapping,
>> >
>> > req->r_callback = writepages_finish;
>> > req->r_inode = inode;
>> > + req->r_enospc_on_full = true;
>> >
>> > /* Format the osd request message and submit the write */
>> > len = 0;
>> > @@ -1689,6 +1690,7 @@ int ceph_uninline_data(struct file *filp, struct page *locked_page)
>> > }
>> >
>> > req->r_mtime = inode->i_mtime;
>> > + req->r_enospc_on_full = true;
>> > err = ceph_osdc_start_request(&fsc->client->osdc, req, false);
>> > if (!err)
>> > err = ceph_osdc_wait_request(&fsc->client->osdc, req);
>> > @@ -1732,6 +1734,7 @@ int ceph_uninline_data(struct file *filp, struct page *locked_page)
>> > }
>> >
>> > req->r_mtime = inode->i_mtime;
>> > + req->r_enospc_on_full = true;
>> > err = ceph_osdc_start_request(&fsc->client->osdc, req, false);
>> > if (!err)
>> > err = ceph_osdc_wait_request(&fsc->client->osdc, req);
>> > @@ -1893,6 +1896,7 @@ static int __ceph_pool_perm_get(struct ceph_inode_info *ci,
>> > err = ceph_osdc_start_request(&fsc->client->osdc, rd_req, false);
>> >
>> > wr_req->r_mtime = ci->vfs_inode.i_mtime;
>> > + wr_req->r_enospc_on_full = true;
>> > err2 = ceph_osdc_start_request(&fsc->client->osdc, wr_req, false);
>> >
>> > if (!err)
>> > diff --git a/fs/ceph/file.c b/fs/ceph/file.c
>> > index a91a4f1fc837..eaed17f90d5f 100644
>> > --- a/fs/ceph/file.c
>> > +++ b/fs/ceph/file.c
>> > @@ -714,6 +714,7 @@ static void ceph_aio_retry_work(struct work_struct *work)
>> > req->r_callback = ceph_aio_complete_req;
>> > req->r_inode = inode;
>> > req->r_priv = aio_req;
>> > + req->r_enospc_on_full = true;
>> >
>> > ret = ceph_osdc_start_request(req->r_osdc, req, false);
>> > out:
>> > @@ -912,6 +913,7 @@ ceph_direct_read_write(struct kiocb *iocb, struct iov_iter *iter,
>> >
>> > osd_req_op_init(req, 1, CEPH_OSD_OP_STARTSYNC, 0);
>> > req->r_mtime = mtime;
>> > + req->r_enospc_on_full = true;
>> > }
>> >
>> > osd_req_op_extent_osd_data_pages(req, 0, pages, len, start,
>> > @@ -1105,6 +1107,7 @@ ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
>> > false, true);
>> >
>> > req->r_mtime = mtime;
>> > + req->r_enospc_on_full = true;
>> > ret = ceph_osdc_start_request(&fsc->client->osdc, req, false);
>> > if (!ret)
>> > ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
>> > @@ -1557,6 +1560,7 @@ static int ceph_zero_partial_object(struct inode *inode,
>> > }
>> >
>> > req->r_mtime = inode->i_mtime;
>> > + req->r_enospc_on_full = true;
>> > ret = ceph_osdc_start_request(&fsc->client->osdc, req, false);
>> > if (!ret) {
>> > ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
>> > diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_client.h
>> > index 17bf1873bb01..f01e93ff03d5 100644
>> > --- a/include/linux/ceph/osd_client.h
>> > +++ b/include/linux/ceph/osd_client.h
>> > @@ -172,6 +172,7 @@ struct ceph_osd_request {
>> >
>> > int r_result;
>> > bool r_got_reply;
>> > + bool r_enospc_on_full; /* return ENOSPC when full */
>> >
>> > struct ceph_osd_client *r_osdc;
>> > struct kref r_kref;
>> > diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
>> > index d61d7a79fdb3..9f40d11b3c68 100644
>> > --- a/net/ceph/osd_client.c
>> > +++ b/net/ceph/osd_client.c
>> > @@ -50,6 +50,7 @@ static void link_linger(struct ceph_osd *osd,
>> > struct ceph_osd_linger_request *lreq);
>> > static void unlink_linger(struct ceph_osd *osd,
>> > struct ceph_osd_linger_request *lreq);
>> > +static void complete_request(struct ceph_osd_request *req, int err);
>> >
>> > #if 1
>> > static inline bool rwsem_is_wrlocked(struct rw_semaphore *sem)
>> > @@ -1643,6 +1644,7 @@ static void __submit_request(struct ceph_osd_request *req, bool wrlocked)
>> > enum calc_target_result ct_res;
>> > bool need_send = false;
>> > bool promoted = false;
>> > + int ret = 0;
>> >
>> > WARN_ON(req->r_tid || req->r_got_reply);
>> > dout("%s req %p wrlocked %d\n", __func__, req, wrlocked);
>> > @@ -1683,6 +1685,8 @@ static void __submit_request(struct ceph_osd_request *req, bool wrlocked)
>> > pr_warn_ratelimited("FULL or reached pool quota\n");
>> > req->r_t.paused = true;
>> > maybe_request_map(osdc);
>> > + if (req->r_enospc_on_full)
>> > + ret = -ENOSPC;
>> > } else if (!osd_homeless(osd)) {
>> > need_send = true;
>> > } else {
>> > @@ -1699,6 +1703,8 @@ static void __submit_request(struct ceph_osd_request *req, bool wrlocked)
>> > link_request(osd, req);
>> > if (need_send)
>> > send_request(req);
>> > + else if (ret)
>> > + complete_request(req, ret);
>>
>> How is this handled in the userspace client? I don't see a similar
>> check in Objecter.
>>
>> Thanks,
>>
>> Ilya
>
> It seems to be handled at a much higher layer in libcephfs. In _write(),
> for instance, we have:
>
> if (objecter->osdmap_pool_full(in->layout.pool_id)) {
> return -ENOSPC;
> }
>
> ...and there's also some EDQUOT handling a little below there as well.
>
> I don't think we can reasonably follow that model in the kernel client
> though. The way it's done in userland seems to require the big client
> mutex be held over large swaths of the code, and that's not the case in
> the kernel client (thankfully).
All it's doing is checking a flag under a lock; the same lock is taken
in ceph_osdc_start_request(). Why would exporting
bool ceph_osdc_pool_full(osdc, pool_id)
{
bool ret;
down_read(&osdc->lock);
ret = ceph_osdmap_flag(osdc, CEPH_OSDMAP_FULL) ||
pool_full(osdc, pool_id);
up_read(&osdc->lock);
return ret;
}
not work? IOW why special case request handling code if you know in
advance that the request is a goner?
Thanks,
Ilya
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