[DLM] dlm_device interface changes [3/6]
Change the user/kernel device interface used by libdlm:
- Add ability for userspace to check the version of the interface. libdlm
can now adapt to different versions of the kernel interface.
- Increase the size of the flags passed in a lock request so all possible
flags can be used from userspace.
- Add an opaque "xid" value for each lock. This "transaction id" will be
used later to associate locks with each other during deadlock detection.
- Add a "timeout" value for each lock. This is used along with the
DLM_LKF_TIMEOUT flag.
Also, remove a fragment of unused code in device_read().
This patch requires updating libdlm which is backward compatible with
older kernels.
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/dlm/user.c b/fs/dlm/user.c
index c7612da..37aad3f 100644
--- a/fs/dlm/user.c
+++ b/fs/dlm/user.c
@@ -33,16 +33,17 @@
struct dlm_lock_params32 {
__u8 mode;
__u8 namelen;
- __u16 flags;
+ __u16 unused;
+ __u32 flags;
__u32 lkid;
__u32 parent;
-
+ __u64 xid;
+ __u64 timeout;
__u32 castparam;
__u32 castaddr;
__u32 bastparam;
__u32 bastaddr;
__u32 lksb;
-
char lvb[DLM_USER_LVB_LEN];
char name[0];
};
@@ -68,6 +69,7 @@
};
struct dlm_lock_result32 {
+ __u32 version[3];
__u32 length;
__u32 user_astaddr;
__u32 user_astparam;
@@ -102,6 +104,8 @@
kb->i.lock.flags = kb32->i.lock.flags;
kb->i.lock.lkid = kb32->i.lock.lkid;
kb->i.lock.parent = kb32->i.lock.parent;
+ kb->i.lock.xid = kb32->i.lock.xid;
+ kb->i.lock.timeout = kb32->i.lock.timeout;
kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam;
kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr;
kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam;
@@ -115,6 +119,10 @@
static void compat_output(struct dlm_lock_result *res,
struct dlm_lock_result32 *res32)
{
+ res32->version[0] = res->version[0];
+ res32->version[1] = res->version[1];
+ res32->version[2] = res->version[2];
+
res32->user_astaddr = (__u32)(long)res->user_astaddr;
res32->user_astparam = (__u32)(long)res->user_astparam;
res32->user_lksb = (__u32)(long)res->user_lksb;
@@ -252,16 +260,18 @@
ua->castaddr = params->castaddr;
ua->bastparam = params->bastparam;
ua->bastaddr = params->bastaddr;
+ ua->xid = params->xid;
if (params->flags & DLM_LKF_CONVERT)
error = dlm_user_convert(ls, ua,
params->mode, params->flags,
- params->lkid, params->lvb);
+ params->lkid, params->lvb,
+ (unsigned long) params->timeout);
else {
error = dlm_user_request(ls, ua,
params->mode, params->flags,
params->name, params->namelen,
- params->parent);
+ (unsigned long) params->timeout);
if (!error)
error = ua->lksb.sb_lkid;
}
@@ -641,6 +651,9 @@
int struct_len;
memset(&result, 0, sizeof(struct dlm_lock_result));
+ result.version[0] = DLM_DEVICE_VERSION_MAJOR;
+ result.version[1] = DLM_DEVICE_VERSION_MINOR;
+ result.version[2] = DLM_DEVICE_VERSION_PATCH;
memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
result.user_lksb = ua->user_lksb;
@@ -699,6 +712,20 @@
return error;
}
+static int copy_version_to_user(char __user *buf, size_t count)
+{
+ struct dlm_device_version ver;
+
+ memset(&ver, 0, sizeof(struct dlm_device_version));
+ ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
+ ver.version[1] = DLM_DEVICE_VERSION_MINOR;
+ ver.version[2] = DLM_DEVICE_VERSION_PATCH;
+
+ if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
+ return -EFAULT;
+ return sizeof(struct dlm_device_version);
+}
+
/* a read returns a single ast described in a struct dlm_lock_result */
static ssize_t device_read(struct file *file, char __user *buf, size_t count,
@@ -710,6 +737,16 @@
DECLARE_WAITQUEUE(wait, current);
int error, type=0, bmode=0, removed = 0;
+ if (count == sizeof(struct dlm_device_version)) {
+ error = copy_version_to_user(buf, count);
+ return error;
+ }
+
+ if (!proc) {
+ log_print("non-version read from control device %zu", count);
+ return -EINVAL;
+ }
+
#ifdef CONFIG_COMPAT
if (count < sizeof(struct dlm_lock_result32))
#else
@@ -747,11 +784,6 @@
}
}
- if (list_empty(&proc->asts)) {
- spin_unlock(&proc->asts_spin);
- return -EAGAIN;
- }
-
/* there may be both completion and blocking asts to return for
the lkb, don't remove lkb from asts list unless no asts remain */
@@ -823,6 +855,7 @@
static const struct file_operations ctl_device_fops = {
.open = ctl_device_open,
.release = ctl_device_close,
+ .read = device_read,
.write = device_write,
.owner = THIS_MODULE,
};