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1, mount with wsync.
2, create a file with O_RDWR, and the request was sent to mds.0:
ceph_atomic_open()-->
ceph_mdsc_do_request(openc)
finish_open(file, dentry, ceph_open)-->
ceph_open()-->
ceph_init_file()-->
ceph_init_file_info()-->
ceph_uninline_data()-->
{
...
if (inline_version == 1 || /* initial version, no data */
inline_version == CEPH_INLINE_NONE)
goto out_unlock;
...
}
The inline_version will be 1, which is the initial version for the
new create file. And here the ci->i_inline_version will keep with 1,
it's buggy.
3, buffer write to the file immediately:
ceph_write_iter()-->
ceph_get_caps(file, need=Fw, want=Fb, ...);
generic_perform_write()-->
a_ops->write_begin()-->
ceph_write_begin()-->
netfs_write_begin()-->
netfs_begin_read()-->
netfs_rreq_submit_slice()-->
netfs_read_from_server()-->
rreq->netfs_ops->issue_read()-->
ceph_netfs_issue_read()-->
{
...
if (ci->i_inline_version != CEPH_INLINE_NONE &&
ceph_netfs_issue_op_inline(subreq))
return;
...
}
ceph_put_cap_refs(ci, Fwb);
The ceph_netfs_issue_op_inline() will send a getattr(Fsr) request to
mds.1.
4, then the mds.1 will request the rd lock for CInode::filelock from
the auth mds.0, the mds.0 will do the CInode::filelock state transation
from excl --> sync, but it need to revoke the Fxwb caps back from the
clients.
While the kernel client has aleady held the Fwb caps and waiting for
the getattr(Fsr).
It's deadlock!
URL: https://tracker.ceph.com/issues/55377
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.