linux.git/fs/dlm, branch v6.6

dlm: fix plock lookup when using multiple lockspaces

2023-08-25T15:31:39+00:00

All posix lock ops, for all lockspaces (gfs2 file systems) are
sent to userspace (dlm_controld) through a single misc device.
The dlm_controld daemon reads the ops from the misc device
and sends them to other cluster nodes using separate, per-lockspace
cluster api communication channels.  The ops for a single lockspace
are ordered at this level, so that the results are received in
the same sequence that the requests were sent.  When the results
are sent back to the kernel via the misc device, they are again
funneled through the single misc device for all lockspaces.  When
the dlm code in the kernel processes the results from the misc
device, these results will be returned in the same sequence that
the requests were sent, on a per-lockspace basis.  A recent change
in this request/reply matching code missed the "per-lockspace"
check (fsid comparison) when matching request and reply, so replies
could be incorrectly matched to requests from other lockspaces.

Cc: stable@vger.kernel.org
Reported-by: Barry Marson 
Fixes: 57e2c2f2d94c ("fs: dlm: fix mismatch of plock results from userspace")
Signed-off-by: Alexander Aring 
Signed-off-by: David Teigland

fs: dlm: don't use RCOM_NAMES for version detection

2023-08-10T15:33:03+00:00

Currently RCOM_STATUS and RCOM_NAMES inclusive their replies are being
used to determine the DLM version. The RCOM_NAMES messages are triggered
in DLM recovery when calling dlm_recover_directory() only. At this time
the DLM version need to be determined. I ran some tests and did not
expirenced some issues. When the DLM version detection was developed
probably I run once in a case of RCOM_NAMES and the version was not
detected yet. However it seems to be not necessary.

For backwards compatibility we still need to accept RCOM_NAMES messages
which are not protected regarding the DLM message reliability layer aka
stateless message. This patch changes that RCOM_NAMES we are sending out
after this patch are not stateless anymore.

Signed-off-by: Alexander Aring 
Signed-off-by: David Teigland

fs: dlm: create midcomms nodes when configure

2023-08-10T15:33:03+00:00

This patch puts the life of a midcomms node the same as a lowcomms
connection. The lowcomms connection lifetime was changed by commit
6f0b0b5d7ae7 ("fs: dlm: remove dlm_node_addrs lookup list"). In the
future the midcomms node instances can be merged with lowcomms
connection structure as the lifetime is the same and states can be
controlled over values or flags.

Before midcomms nodes were generated during version detection. This is
not necessary anymore when the nodes are created when the cluster
manager configures DLM via configfs. When a midcomms node is created over
configfs it well set DLM_VERSION_NOT_SET as version. This indicates that
the version of the midcomms node is still unknown and need to be probed
via certain rcom messages.

Signed-off-by: Alexander Aring 
Signed-off-by: David Teigland

fs: dlm: constify receive buffer

2023-08-10T15:33:03+00:00

The dlm receive buffer should be never manipulated as DLM is the last
instance of parsing layer. This patch constify the whole receive buffer
so we are sure it never gets manipulated when it's being parsed.

Signed-off-by: Alexander Aring 
Signed-off-by: David Teigland

fs: dlm: drop rxbuf manipulation in dlm_recover_master_copy

2023-08-10T15:33:03+00:00

Currently dlm_recover_master_copy() manipulates the receive buffer of an
rcom lock message and modifies it on the fly so a later memcpy() to a
new rcom message with the same message has those new values. This patch
avoids manipulating the received rcom message by store the values for
the new rcom message in paremter assigned with call by reference. Later
when dlm_send_rcom_lock() constructs a new message and memcpy() the
receive buffer those values will be set on the new constructed message.

Signed-off-by: Alexander Aring 
Signed-off-by: David Teigland

fs: dlm: drop rxbuf manipulation in dlm_copy_master_names

2023-08-10T15:33:03+00:00

This patch removes the manipulation of the receive buffer in case of an
error and be sure the buffer is null terminated before an error
messagea is printed out. Instead of manipulate the receive buffer we
tell inside the format string the maximum length the string buffer is
being read.

Signed-off-by: Alexander Aring 
Signed-off-by: David Teigland

fs: dlm: get recovery sequence number as parameter

2023-08-10T15:33:03+00:00

This patch removes a read of the ls->ls_recover_seq uint64_t number in
_create_rcom(). If the ls->ls_recover_seq is readed the ls_recover_lock
need to held. However this number was always readed before when any rcom
message is received and it's not necessary to read it again from a per
lockspace variable to use it for the replying message. This patch will
pass the sequence number as parameter so another read of ls->ls_recover_seq
and holding the ls->ls_recover_lock is not required.

Signed-off-by: Alexander Aring 
Signed-off-by: David Teigland

fs: dlm: cleanup lock order

2023-08-10T15:33:03+00:00

This patch cleanups the lock order to hold at first the close_lock and
then held the nodes_srcu read lock. Probably it will never be a problem
as nodes_srcu is only a read lock preventing the node pointer getting
freed.

Signed-off-by: Alexander Aring 
Signed-off-by: David Teigland

fs: dlm: remove clear_members_cb

2023-08-10T15:33:03+00:00

This patch is just a small cleanup to directly call
remove_remote_member() instead of going over clear_members_cb() which
just calls remove_remote_member().

Signed-off-by: Alexander Aring 
Signed-off-by: David Teigland

fs: dlm: add plock dev tracepoints

2023-08-10T15:33:03+00:00

I currently debug nfs plock handling and introduce those two tracepoints
for getting more information about what is happening there if the user
space reads plock operations from kernel and writing the result back.

Signed-off-by: Alexander Aring 
Signed-off-by: David Teigland