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ocfs2: Fix endian bug in o2dlm protocol negotiation.
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struct dlm_query_join_packet is made up of four one-byte fields.  They
are effectively in big-endian order already.  However, little-endian
machines swap them before putting the packet on the wire (because
query_join's response is a status, and that status is treated as a u32
on the wire).  Thus, a big-endian and little-endian machines will
treat this structure differently.

The solution is to have little-endian machines swap the structure when
converting from the structure to the u32 representation.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
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Joel Becker authored and Mark Fasheh committed Mar 10, 2008
1 parent 2af37ce commit 0f71b7b
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Showing 2 changed files with 76 additions and 45 deletions.
20 changes: 11 additions & 9 deletions fs/ocfs2/dlm/dlmcommon.h
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Original file line number Diff line number Diff line change
Expand Up @@ -602,17 +602,19 @@ enum dlm_query_join_response_code {
JOIN_PROTOCOL_MISMATCH,
};

struct dlm_query_join_packet {
u8 code; /* Response code. dlm_minor and fs_minor
are only valid if this is JOIN_OK */
u8 dlm_minor; /* The minor version of the protocol the
dlm is speaking. */
u8 fs_minor; /* The minor version of the protocol the
filesystem is speaking. */
u8 reserved;
};

union dlm_query_join_response {
u32 intval;
struct {
u8 code; /* Response code. dlm_minor and fs_minor
are only valid if this is JOIN_OK */
u8 dlm_minor; /* The minor version of the protocol the
dlm is speaking. */
u8 fs_minor; /* The minor version of the protocol the
filesystem is speaking. */
u8 reserved;
} packet;
struct dlm_query_join_packet packet;
};

struct dlm_lock_request
Expand Down
101 changes: 65 additions & 36 deletions fs/ocfs2/dlm/dlmdomain.c
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Original file line number Diff line number Diff line change
Expand Up @@ -713,14 +713,46 @@ static int dlm_query_join_proto_check(char *proto_type, int node,
return rc;
}

/*
* struct dlm_query_join_packet is made up of four one-byte fields. They
* are effectively in big-endian order already. However, little-endian
* machines swap them before putting the packet on the wire (because
* query_join's response is a status, and that status is treated as a u32
* on the wire). Thus, a big-endian and little-endian machines will treat
* this structure differently.
*
* The solution is to have little-endian machines swap the structure when
* converting from the structure to the u32 representation. This will
* result in the structure having the correct format on the wire no matter
* the host endian format.
*/
static void dlm_query_join_packet_to_wire(struct dlm_query_join_packet *packet,
u32 *wire)
{
union dlm_query_join_response response;

response.packet = *packet;
*wire = cpu_to_be32(response.intval);
}

static void dlm_query_join_wire_to_packet(u32 wire,
struct dlm_query_join_packet *packet)
{
union dlm_query_join_response response;

response.intval = cpu_to_be32(wire);
*packet = response.packet;
}

static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
void **ret_data)
{
struct dlm_query_join_request *query;
union dlm_query_join_response response = {
.packet.code = JOIN_DISALLOW,
struct dlm_query_join_packet packet = {
.code = JOIN_DISALLOW,
};
struct dlm_ctxt *dlm = NULL;
u32 response;
u8 nodenum;

query = (struct dlm_query_join_request *) msg->buf;
Expand All @@ -737,11 +769,11 @@ static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
mlog(0, "node %u is not in our live map yet\n",
query->node_idx);

response.packet.code = JOIN_DISALLOW;
packet.code = JOIN_DISALLOW;
goto respond;
}

response.packet.code = JOIN_OK_NO_MAP;
packet.code = JOIN_OK_NO_MAP;

spin_lock(&dlm_domain_lock);
dlm = __dlm_lookup_domain_full(query->domain, query->name_len);
Expand All @@ -760,7 +792,7 @@ static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
mlog(0, "disallow join as node %u does not "
"have node %u in its nodemap\n",
query->node_idx, nodenum);
response.packet.code = JOIN_DISALLOW;
packet.code = JOIN_DISALLOW;
goto unlock_respond;
}
}
Expand All @@ -780,23 +812,23 @@ static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
/*If this is a brand new context and we
* haven't started our join process yet, then
* the other node won the race. */
response.packet.code = JOIN_OK_NO_MAP;
packet.code = JOIN_OK_NO_MAP;
} else if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
/* Disallow parallel joins. */
response.packet.code = JOIN_DISALLOW;
packet.code = JOIN_DISALLOW;
} else if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
mlog(0, "node %u trying to join, but recovery "
"is ongoing.\n", bit);
response.packet.code = JOIN_DISALLOW;
packet.code = JOIN_DISALLOW;
} else if (test_bit(bit, dlm->recovery_map)) {
mlog(0, "node %u trying to join, but it "
"still needs recovery.\n", bit);
response.packet.code = JOIN_DISALLOW;
packet.code = JOIN_DISALLOW;
} else if (test_bit(bit, dlm->domain_map)) {
mlog(0, "node %u trying to join, but it "
"is still in the domain! needs recovery?\n",
bit);
response.packet.code = JOIN_DISALLOW;
packet.code = JOIN_DISALLOW;
} else {
/* Alright we're fully a part of this domain
* so we keep some state as to who's joining
Expand All @@ -807,19 +839,15 @@ static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
if (dlm_query_join_proto_check("DLM", bit,
&dlm->dlm_locking_proto,
&query->dlm_proto)) {
response.packet.code =
JOIN_PROTOCOL_MISMATCH;
packet.code = JOIN_PROTOCOL_MISMATCH;
} else if (dlm_query_join_proto_check("fs", bit,
&dlm->fs_locking_proto,
&query->fs_proto)) {
response.packet.code =
JOIN_PROTOCOL_MISMATCH;
packet.code = JOIN_PROTOCOL_MISMATCH;
} else {
response.packet.dlm_minor =
query->dlm_proto.pv_minor;
response.packet.fs_minor =
query->fs_proto.pv_minor;
response.packet.code = JOIN_OK;
packet.dlm_minor = query->dlm_proto.pv_minor;
packet.fs_minor = query->fs_proto.pv_minor;
packet.code = JOIN_OK;
__dlm_set_joining_node(dlm, query->node_idx);
}
}
Expand All @@ -830,9 +858,10 @@ static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
spin_unlock(&dlm_domain_lock);

respond:
mlog(0, "We respond with %u\n", response.packet.code);
mlog(0, "We respond with %u\n", packet.code);

return response.intval;
dlm_query_join_packet_to_wire(&packet, &response);
return response;
}

static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data,
Expand Down Expand Up @@ -968,7 +997,8 @@ static int dlm_request_join(struct dlm_ctxt *dlm,
{
int status;
struct dlm_query_join_request join_msg;
union dlm_query_join_response join_resp;
struct dlm_query_join_packet packet;
u32 join_resp;

mlog(0, "querying node %d\n", node);

Expand All @@ -984,11 +1014,12 @@ static int dlm_request_join(struct dlm_ctxt *dlm,

status = o2net_send_message(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY, &join_msg,
sizeof(join_msg), node,
&join_resp.intval);
&join_resp);
if (status < 0 && status != -ENOPROTOOPT) {
mlog_errno(status);
goto bail;
}
dlm_query_join_wire_to_packet(join_resp, &packet);

/* -ENOPROTOOPT from the net code means the other side isn't
listening for our message type -- that's fine, it means
Expand All @@ -997,10 +1028,10 @@ static int dlm_request_join(struct dlm_ctxt *dlm,
if (status == -ENOPROTOOPT) {
status = 0;
*response = JOIN_OK_NO_MAP;
} else if (join_resp.packet.code == JOIN_DISALLOW ||
join_resp.packet.code == JOIN_OK_NO_MAP) {
*response = join_resp.packet.code;
} else if (join_resp.packet.code == JOIN_PROTOCOL_MISMATCH) {
} else if (packet.code == JOIN_DISALLOW ||
packet.code == JOIN_OK_NO_MAP) {
*response = packet.code;
} else if (packet.code == JOIN_PROTOCOL_MISMATCH) {
mlog(ML_NOTICE,
"This node requested DLM locking protocol %u.%u and "
"filesystem locking protocol %u.%u. At least one of "
Expand All @@ -1012,14 +1043,12 @@ static int dlm_request_join(struct dlm_ctxt *dlm,
dlm->fs_locking_proto.pv_minor,
node);
status = -EPROTO;
*response = join_resp.packet.code;
} else if (join_resp.packet.code == JOIN_OK) {
*response = join_resp.packet.code;
*response = packet.code;
} else if (packet.code == JOIN_OK) {
*response = packet.code;
/* Use the same locking protocol as the remote node */
dlm->dlm_locking_proto.pv_minor =
join_resp.packet.dlm_minor;
dlm->fs_locking_proto.pv_minor =
join_resp.packet.fs_minor;
dlm->dlm_locking_proto.pv_minor = packet.dlm_minor;
dlm->fs_locking_proto.pv_minor = packet.fs_minor;
mlog(0,
"Node %d responds JOIN_OK with DLM locking protocol "
"%u.%u and fs locking protocol %u.%u\n",
Expand All @@ -1031,11 +1060,11 @@ static int dlm_request_join(struct dlm_ctxt *dlm,
} else {
status = -EINVAL;
mlog(ML_ERROR, "invalid response %d from node %u\n",
join_resp.packet.code, node);
packet.code, node);
}

mlog(0, "status %d, node %d response is %d\n", status, node,
*response);
*response);

bail:
return status;
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