On Sat, Apr 23, 2016 at 6:48 PM, Noah Watkins <noahwatkins@xxxxxxxxx> wrote:
> I have a patch for this (below), but I see something that doesn't seem
> quite right.
>
> Here is a simple fs client. When its running by itself the fstat/sec
> rate is high. When a second client copy of this client starts, the
> first client slows down as expected, but the new client blocks. I
> would expect both clients to make progress, but until the first client
> exits, the second client is blocked.
Ugh. Clearly we have a cap release sequence bug — probably the client
is spinning off new requests instead of blocking them on a cap
release. Can you create a tracker for it?
-Greg
>
> fd = cephfs.open('file-1', 'w', 0755)
> count = 0
> start = time.time()
> while True:
> stat = cephfs.fstat(fd)
> count += 1
> if time.time() > (start + 1):
> print(count)
> count = 0
> start = time.time()
>
> - Noah
>
> Patch:
>
> 709840b - fsclient: fstat can take inode all cap (10 minutes ago) <Noah Watkins>
> diff --git a/src/client/Client.cc b/src/client/Client.cc
> index 7fcd907..94e4db5 100644
> --- a/src/client/Client.cc
> +++ b/src/client/Client.cc
> @@ -8668,16 +8668,16 @@ int Client::_fsync(Fh *f, bool syncdataonly)
> return _fsync(f->inode.get(), syncdataonly);
> }
>
> -int Client::fstat(int fd, struct stat *stbuf)
> +int Client::fstat(int fd, struct stat *stbuf, int mask)
> {
> Mutex::Locker lock(client_lock);
> - tout(cct) << "fstat" << std::endl;
> + tout(cct) << "fstat" << " mask " << mask << std::endl;
> tout(cct) << fd << std::endl;
>
> Fh *f = get_filehandle(fd);
> if (!f)
> return -EBADF;
> - int r = _getattr(f->inode, -1);
> + int r = _getattr(f->inode, mask);
> if (r < 0)
> return r;
> fill_stat(f->inode, stbuf, NULL);
> diff --git a/src/client/Client.h b/src/client/Client.h
> index d912db0..860f28b 100644
> --- a/src/client/Client.h
> +++ b/src/client/Client.h
> @@ -981,7 +981,7 @@ public:
> int fake_write_size(int fd, loff_t size);
> int ftruncate(int fd, loff_t size);
> int fsync(int fd, bool syncdataonly);
> - int fstat(int fd, struct stat *stbuf);
> + int fstat(int fd, struct stat *stbuf, int mask=CEPH_STAT_CAP_INODE_ALL);
> int fallocate(int fd, int mode, loff_t offset, loff_t length);
>
> On Wed, Apr 13, 2016 at 6:49 PM, Yan, Zheng <ukernel@xxxxxxxxx> wrote:
>> On Thu, Apr 14, 2016 at 1:26 AM, Noah Watkins <noahwatkins@xxxxxxxxx> wrote:
>>> In the libcephfs client it looks like both `Client::stat` and
>>> `Client::lstat` use a default mask of CEPH_STAT_CAP_INODE_ALL and are
>>> able to return immediately from `Client::_getattr` without making an
>>> MDS request. However, `Client::fstat` uses hard-coded -1 as the cap
>>> mask and always issues a MDS request. Is this the intended behavior,
>>> and if so, what are different semantics of fstat that make this a
>>> requirement?
>>
>> I think it's a bug, Client::fstat should use CEPH_STAT_CAP_INODE_ALL too.
>>
>> Regards
>> Yan, Zheng
>>
>>>
>>> Thanks,
>>> Noah
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