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ocfs2: Add the 'set version' message to the ocfs2_control device.
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The "SETV" message sets the filesystem locking protocol version as
negotiated by the client.  The client negotiates based on the maximum
version advertised in /sys/fs/ocfs2/max_locking_protocol.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
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Joel Becker authored and Mark Fasheh committed Apr 18, 2008
1 parent 3cfd4ab commit d4b95ee
Showing 1 changed file with 119 additions and 12 deletions.
131 changes: 119 additions & 12 deletions fs/ocfs2/stack_user.c
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Original file line number Diff line number Diff line change
Expand Up @@ -40,7 +40,7 @@
* unknown, -EINVAL is returned. Once the negotiation is complete, the
* client can start sending messages.
*
* The T01 protocol only has two messages. First is the "SETN" message.
* The T01 protocol has three messages. First is the "SETN" message.
* It has the following syntax:
*
* SETN<space><8-char-hex-nodenum><newline>
Expand All @@ -50,8 +50,22 @@
* The "SETN" message must be the first message following the protocol.
* It tells ocfs2_control the local node number.
*
* Once the local node number has been set, the "DOWN" message can be
* sent for node down notification. It has the following syntax:
* Next comes the "SETV" message. It has the following syntax:
*
* SETV<space><2-char-hex-major><space><2-char-hex-minor><newline>
*
* This is 11 characters.
*
* The "SETV" message sets the filesystem locking protocol version as
* negotiated by the client. The client negotiates based on the maximum
* version advertised in /sys/fs/ocfs2/max_locking_protocol. The major
* number from the "SETV" message must match
* user_stack.sp_proto->lp_max_version.pv_major, and the minor number
* must be less than or equal to ...->lp_max_version.pv_minor.
*
* Once this information has been set, mounts will be allowed. From this
* point on, the "DOWN" message can be sent for node down notification.
* It has the following syntax:
*
* DOWN<space><32-char-cap-hex-uuid><space><8-char-hex-nodenum><newline>
*
Expand Down Expand Up @@ -79,9 +93,12 @@
#define OCFS2_CONTROL_MESSAGE_OP_LEN 4
#define OCFS2_CONTROL_MESSAGE_SETNODE_OP "SETN"
#define OCFS2_CONTROL_MESSAGE_SETNODE_TOTAL_LEN 14
#define OCFS2_CONTROL_MESSAGE_SETVERSION_OP "SETV"
#define OCFS2_CONTROL_MESSAGE_SETVERSION_TOTAL_LEN 11
#define OCFS2_CONTROL_MESSAGE_DOWN_OP "DOWN"
#define OCFS2_CONTROL_MESSAGE_DOWN_TOTAL_LEN 47
#define OCFS2_TEXT_UUID_LEN 32
#define OCFS2_CONTROL_MESSAGE_VERNUM_LEN 2
#define OCFS2_CONTROL_MESSAGE_NODENUM_LEN 8

/*
Expand All @@ -97,6 +114,7 @@ struct ocfs2_control_private {
struct list_head op_list;
int op_state;
int op_this_node;
struct ocfs2_protocol_version op_proto;
};

/* SETN<space><8-char-hex-nodenum><newline> */
Expand All @@ -107,6 +125,16 @@ struct ocfs2_control_message_setn {
char newline;
};

/* SETV<space><2-char-hex-major><space><2-char-hex-minor><newline> */
struct ocfs2_control_message_setv {
char tag[OCFS2_CONTROL_MESSAGE_OP_LEN];
char space1;
char major[OCFS2_CONTROL_MESSAGE_VERNUM_LEN];
char space2;
char minor[OCFS2_CONTROL_MESSAGE_VERNUM_LEN];
char newline;
};

/* DOWN<space><32-char-cap-hex-uuid><space><8-char-hex-nodenum><newline> */
struct ocfs2_control_message_down {
char tag[OCFS2_CONTROL_MESSAGE_OP_LEN];
Expand All @@ -120,11 +148,13 @@ struct ocfs2_control_message_down {
union ocfs2_control_message {
char tag[OCFS2_CONTROL_MESSAGE_OP_LEN];
struct ocfs2_control_message_setn u_setn;
struct ocfs2_control_message_setv u_setv;
struct ocfs2_control_message_down u_down;
};

static atomic_t ocfs2_control_opened;
static int ocfs2_control_this_node = -1;
static struct ocfs2_protocol_version running_proto;

static LIST_HEAD(ocfs2_live_connection_list);
static LIST_HEAD(ocfs2_control_private_list);
Expand Down Expand Up @@ -264,8 +294,9 @@ static void ocfs2_control_send_down(const char *uuid,
/*
* Called whenever configuration elements are sent to /dev/ocfs2_control.
* If all configuration elements are present, try to set the global
* values. If not, return -EAGAIN. If there is a problem, return a
* different error.
* values. If there is a problem, return an error. Skip any missing
* elements, and only bump ocfs2_control_opened when we have all elements
* and are successful.
*/
static int ocfs2_control_install_private(struct file *file)
{
Expand All @@ -275,15 +306,32 @@ static int ocfs2_control_install_private(struct file *file)

BUG_ON(p->op_state != OCFS2_CONTROL_HANDSHAKE_PROTOCOL);

if (p->op_this_node < 0)
mutex_lock(&ocfs2_control_lock);

if (p->op_this_node < 0) {
set_p = 0;
} else if ((ocfs2_control_this_node >= 0) &&
(ocfs2_control_this_node != p->op_this_node)) {
rc = -EINVAL;
goto out_unlock;
}

mutex_lock(&ocfs2_control_lock);
if (ocfs2_control_this_node < 0) {
if (set_p)
ocfs2_control_this_node = p->op_this_node;
} else if (ocfs2_control_this_node != p->op_this_node)
if (!p->op_proto.pv_major) {
set_p = 0;
} else if (!list_empty(&ocfs2_live_connection_list) &&
((running_proto.pv_major != p->op_proto.pv_major) ||
(running_proto.pv_minor != p->op_proto.pv_minor))) {
rc = -EINVAL;
goto out_unlock;
}

if (set_p) {
ocfs2_control_this_node = p->op_this_node;
running_proto.pv_major = p->op_proto.pv_major;
running_proto.pv_minor = p->op_proto.pv_minor;
}

out_unlock:
mutex_unlock(&ocfs2_control_lock);

if (!rc && set_p) {
Expand Down Expand Up @@ -327,6 +375,56 @@ static int ocfs2_control_do_setnode_msg(struct file *file,
return ocfs2_control_install_private(file);
}

static int ocfs2_control_do_setversion_msg(struct file *file,
struct ocfs2_control_message_setv *msg)
{
long major, minor;
char *ptr = NULL;
struct ocfs2_control_private *p = file->private_data;
struct ocfs2_protocol_version *max =
&user_stack.sp_proto->lp_max_version;

if (ocfs2_control_get_handshake_state(file) !=
OCFS2_CONTROL_HANDSHAKE_PROTOCOL)
return -EINVAL;

if (strncmp(msg->tag, OCFS2_CONTROL_MESSAGE_SETVERSION_OP,
OCFS2_CONTROL_MESSAGE_OP_LEN))
return -EINVAL;

if ((msg->space1 != ' ') || (msg->space2 != ' ') ||
(msg->newline != '\n'))
return -EINVAL;
msg->space1 = msg->space2 = msg->newline = '\0';

major = simple_strtol(msg->major, &ptr, 16);
if (!ptr || *ptr)
return -EINVAL;
minor = simple_strtol(msg->minor, &ptr, 16);
if (!ptr || *ptr)
return -EINVAL;

/*
* The major must be between 1 and 255, inclusive. The minor
* must be between 0 and 255, inclusive. The version passed in
* must be within the maximum version supported by the filesystem.
*/
if ((major == LONG_MIN) || (major == LONG_MAX) ||
(major > (u8)-1) || (major < 1))
return -ERANGE;
if ((minor == LONG_MIN) || (minor == LONG_MAX) ||
(minor > (u8)-1) || (minor < 0))
return -ERANGE;
if ((major != max->pv_major) ||
(minor > max->pv_minor))
return -EINVAL;

p->op_proto.pv_major = major;
p->op_proto.pv_minor = minor;

return ocfs2_control_install_private(file);
}

static int ocfs2_control_do_down_msg(struct file *file,
struct ocfs2_control_message_down *msg)
{
Expand Down Expand Up @@ -379,6 +477,10 @@ static ssize_t ocfs2_control_message(struct file *file,
!strncmp(msg.tag, OCFS2_CONTROL_MESSAGE_SETNODE_OP,
OCFS2_CONTROL_MESSAGE_OP_LEN))
ret = ocfs2_control_do_setnode_msg(file, &msg.u_setn);
else if ((count == OCFS2_CONTROL_MESSAGE_SETVERSION_TOTAL_LEN) &&
!strncmp(msg.tag, OCFS2_CONTROL_MESSAGE_SETVERSION_OP,
OCFS2_CONTROL_MESSAGE_OP_LEN))
ret = ocfs2_control_do_setversion_msg(file, &msg.u_setv);
else if ((count == OCFS2_CONTROL_MESSAGE_DOWN_TOTAL_LEN) &&
!strncmp(msg.tag, OCFS2_CONTROL_MESSAGE_DOWN_OP,
OCFS2_CONTROL_MESSAGE_OP_LEN))
Expand Down Expand Up @@ -471,8 +573,13 @@ static int ocfs2_control_release(struct inode *inode, struct file *file)
"an emergency restart!\n");
emergency_restart();
}
/* Last valid close clears the node number */
/*
* Last valid close clears the node number and resets
* the locking protocol version
*/
ocfs2_control_this_node = -1;
running_proto.pv_major = 0;
running_proto.pv_major = 0;
}

out:
Expand Down

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