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pnfs: added status flags and ref count to struct pnfs_device

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pnfs_device.status remembers whether a given device has been GRANTED/REVOKED

pnfs_device.layout_count tracks the number of layouts using the device, incremented by pnfs_file_device_get() and decremented by pnfs_file_device_put().  when pnfs_file_device_put() takes layout_count to 0, remove and free the device only if it's flagged as REVOKED

because pnfs_file_device_get() modifies pnfs_device.layout_count, we can no longer use a shared lock; changed pnfs_file_device.lock from SRWLOCK to CRITICAL_SECTION, and moved to pnfs_device.lock to document the fact that it's used for pnfs_device.status and pnfs_device.layout_count

Signed-off-by: Casey Bodley <cbodley@citi.umich.edu>
This commit is contained in:
Casey Bodley 2010-12-01 15:06:22 -05:00
parent 2286f7a1e3
commit e3119c281e
3 changed files with 68 additions and 25 deletions
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75
daemon/pnfs_device.c
View file

@ -43,6 +43,7 @@ struct pnfs_file_device_list {
static enum pnfs_status file_device_create(
IN const unsigned char *deviceid,
IN struct pnfs_file_device_list *devices,
OUT pnfs_file_device **device_out)
{
enum pnfs_status status = PNFS_SUCCESS;
@ -55,7 +56,8 @@ static enum pnfs_status file_device_create(
}
memcpy(device->device.deviceid, deviceid, PNFS_DEVICEID_SIZE);
InitializeSRWLock(&device->lock);
device->devices = devices;
InitializeCriticalSection(&device->device.lock);
*device_out = device;
out:
return status;
@ -94,7 +96,7 @@ static enum pnfs_status file_device_find_or_create(
if (entry == NULL) {
/* create a new device */
pnfs_file_device *device;
status = file_device_create(deviceid, &device);
status = file_device_create(deviceid, devices, &device);
if (status == PNFS_SUCCESS) {
/* add it to the list */
list_add_tail(&devices->head, &device->entry);
@ -172,39 +174,66 @@ enum pnfs_status pnfs_file_device_get(
if (status)
goto out;
AcquireSRWLockShared(&device->lock);
status = device->device.type == 0 ? PNFS_PENDING : PNFS_SUCCESS;
ReleaseSRWLockShared(&device->lock);
EnterCriticalSection(&device->device.lock);
if (status == PNFS_PENDING) {
AcquireSRWLockExclusive(&device->lock);
/* don't give out a device that's been revoked */
if (device->device.status & PNFS_DEVICE_REVOKED)
status = PNFSERR_NO_DEVICE;
else if (device->device.status & PNFS_DEVICE_GRANTED)
status = PNFS_SUCCESS;
else {
nfsstat = pnfs_rpc_getdeviceinfo(session, deviceid, device);
if (nfsstat == NFS4_OK) {
device->device.status = PNFS_DEVICE_GRANTED;
status = PNFS_SUCCESS;
status = device->device.type == 0 ? PNFS_PENDING : PNFS_SUCCESS;
if (status == PNFS_PENDING) {
nfsstat = pnfs_rpc_getdeviceinfo(session, deviceid, device);
if (nfsstat == NFS4_OK) {
status = PNFS_SUCCESS;
dprintf(FDLVL, "Received device info:\n");
dprint_device(FDLVL, device);
} else {
status = PNFSERR_NO_DEVICE;
dprintf(FDLVL, "Received device info:\n");
dprint_device(FDLVL, device);
} else {
status = PNFSERR_NO_DEVICE;
eprintf("pnfs_rpc_getdeviceinfo() failed with %s\n",
nfs_error_string(nfsstat));
}
eprintf("pnfs_rpc_getdeviceinfo() failed with %s\n",
nfs_error_string(nfsstat));
}
ReleaseSRWLockExclusive(&device->lock);
}
*device_out = device;
if (status == PNFS_SUCCESS) {
device->device.layout_count++;
dprintf(FDLVL, "pnfs_file_device_get() -> %u\n",
device->device.layout_count);
*device_out = device;
}
LeaveCriticalSection(&device->device.lock);
out:
dprintf(FDLVL, "<-- pnfs_file_device_get() returning %s\n",
pnfs_error_string(status));
return status;
}
void pnfs_file_device_put(
IN pnfs_file_device *device)
{
uint32_t count;
EnterCriticalSection(&device->device.lock);
count = --device->device.layout_count;
dprintf(FDLVL, "pnfs_file_device_put() -> %u\n", count);
/* if the device was revoked, remove/free the device on last reference */
if (count == 0 && device->device.status & PNFS_DEVICE_REVOKED) {
EnterCriticalSection(&device->devices->lock);
list_remove(&device->entry);
LeaveCriticalSection(&device->devices->lock);
LeaveCriticalSection(&device->device.lock);
file_device_free(device);
dprintf(FDLVL, "revoked file device freed after last reference\n");
} else {
LeaveCriticalSection(&device->device.lock);
}
}
static enum pnfs_status data_client_status(
IN pnfs_data_server *server,
OUT nfs41_client **client_out)