Commit 85160e03 authored by Pavel Shilovsky's avatar Pavel Shilovsky Committed by Steve French
Browse files

CIFS: Implement caching mechanism for mandatory brlocks 



If we have an oplock and negotiate mandatory locking style we handle
all brlock requests on the client.

Signed-off-by: default avatarPavel Shilovsky <piastry@etersoft.ru>
Acked-off-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarSteve French <smfrench@gmail.com>
parent 42274bb2

fs/cifs/cifsglob.h

+2 −0
Original line number Diff line number Diff line
@@ -496,6 +496,8 @@ extern struct cifs_tcon *cifs_sb_master_tcon(struct cifs_sb_info *cifs_sb); 
 */

struct cifsLockInfo {

	struct list_head llist;	/* pointer to next cifsLockInfo */

	struct list_head blist; /* pointer to locks blocked on this */

	wait_queue_head_t block_q;

	__u64 offset;

	__u64 length;

	__u32 pid;

fs/cifs/file.c

+195 −11
Original line number Diff line number Diff line
@@ -275,11 +275,14 @@ cifs_new_fileinfo(__u16 fileHandle, struct file *file, 
	spin_unlock(&cifs_file_list_lock);



	cifs_set_oplock_level(pCifsInode, oplock);

	pCifsInode->can_cache_brlcks = pCifsInode->clientCanCacheAll;



	file->private_data = pCifsFile;

	return pCifsFile;

}



static void cifs_del_lock_waiters(struct cifsLockInfo *lock);



/*

 * Release a reference on the file private data. This may involve closing

 * the filehandle out on the server. Must be called without holding
@@ -335,6 +338,7 @@ void cifsFileInfo_put(struct cifsFileInfo *cifs_file) 
		if (li->netfid != cifs_file->netfid)

			continue;

		list_del(&li->llist);

		cifs_del_lock_waiters(li);

		kfree(li);

	}

	mutex_unlock(&cifsi->lock_mutex);
@@ -640,24 +644,182 @@ int cifs_closedir(struct inode *inode, struct file *file) 
	return rc;

}



static int store_file_lock(struct cifsInodeInfo *cinode, __u64 len,

			   __u64 offset, __u8 type, __u16 netfid)

static struct cifsLockInfo *

cifs_lock_init(__u64 len, __u64 offset, __u8 type, __u16 netfid)

{

	struct cifsLockInfo *li =

		kmalloc(sizeof(struct cifsLockInfo), GFP_KERNEL);

	if (li == NULL)

		return -ENOMEM;

	if (!li)

		return li;

	li->netfid = netfid;

	li->offset = offset;

	li->length = len;

	li->type = type;

	li->pid = current->tgid;

	INIT_LIST_HEAD(&li->blist);

	init_waitqueue_head(&li->block_q);

	return li;

}



static void

cifs_del_lock_waiters(struct cifsLockInfo *lock)

{

	struct cifsLockInfo *li, *tmp;

	list_for_each_entry_safe(li, tmp, &lock->blist, blist) {

		list_del_init(&li->blist);

		wake_up(&li->block_q);

	}

}



static bool

cifs_find_lock_conflict(struct cifsInodeInfo *cinode, __u64 offset,

			__u64 length, __u8 type, __u16 netfid,

			struct cifsLockInfo **conf_lock)

{

	struct cifsLockInfo *li, *tmp;



	list_for_each_entry_safe(li, tmp, &cinode->llist, llist) {

		if (offset + length <= li->offset ||

		    offset >= li->offset + li->length)

			continue;

		else if ((type & LOCKING_ANDX_SHARED_LOCK) &&

			 ((netfid == li->netfid && current->tgid == li->pid) ||

			  type == li->type))

			continue;

		else {

			*conf_lock = li;

			return true;

		}

	}

	return false;

}



static int

cifs_lock_test(struct cifsInodeInfo *cinode, __u64 offset, __u64 length,

	       __u8 type, __u16 netfid, struct file_lock *flock)

{

	int rc = 0;

	struct cifsLockInfo *conf_lock;

	bool exist;



	mutex_lock(&cinode->lock_mutex);



	exist = cifs_find_lock_conflict(cinode, offset, length, type, netfid,

					&conf_lock);

	if (exist) {

		flock->fl_start = conf_lock->offset;

		flock->fl_end = conf_lock->offset + conf_lock->length - 1;

		flock->fl_pid = conf_lock->pid;

		if (conf_lock->type & LOCKING_ANDX_SHARED_LOCK)

			flock->fl_type = F_RDLCK;

		else

			flock->fl_type = F_WRLCK;

	} else if (!cinode->can_cache_brlcks)

		rc = 1;

	else

		flock->fl_type = F_UNLCK;



	mutex_unlock(&cinode->lock_mutex);

	return rc;

}



static int

cifs_lock_add(struct cifsInodeInfo *cinode, __u64 len, __u64 offset,

	      __u8 type, __u16 netfid)

{

	struct cifsLockInfo *li;



	li = cifs_lock_init(len, offset, type, netfid);

	if (!li)

		return -ENOMEM;



	mutex_lock(&cinode->lock_mutex);

	list_add_tail(&li->llist, &cinode->llist);

	mutex_unlock(&cinode->lock_mutex);

	return 0;

}



static int

cifs_lock_add_if(struct cifsInodeInfo *cinode, __u64 offset, __u64 length,

		 __u8 type, __u16 netfid, bool wait)

{

	struct cifsLockInfo *lock, *conf_lock;

	bool exist;

	int rc = 0;



	lock = cifs_lock_init(length, offset, type, netfid);

	if (!lock)

		return -ENOMEM;



try_again:

	exist = false;

	mutex_lock(&cinode->lock_mutex);



	exist = cifs_find_lock_conflict(cinode, offset, length, type, netfid,

					&conf_lock);

	if (!exist && cinode->can_cache_brlcks) {

		list_add_tail(&lock->llist, &cinode->llist);

		mutex_unlock(&cinode->lock_mutex);

		return rc;

	}



	if (!exist)

		rc = 1;

	else if (!wait)

		rc = -EACCES;

	else {

		list_add_tail(&lock->blist, &conf_lock->blist);

		mutex_unlock(&cinode->lock_mutex);

		rc = wait_event_interruptible(lock->block_q,

					(lock->blist.prev == &lock->blist) &&

					(lock->blist.next == &lock->blist));

		if (!rc)

			goto try_again;

		else {

			mutex_lock(&cinode->lock_mutex);

			list_del_init(&lock->blist);

			mutex_unlock(&cinode->lock_mutex);

		}

	}



	kfree(lock);

	mutex_unlock(&cinode->lock_mutex);

	return rc;

}



static int

cifs_push_locks(struct cifsFileInfo *cfile)

{

	int xid, rc = 0, stored_rc;

	struct cifsLockInfo *li, *tmp;

	struct cifs_tcon *tcon;

	struct cifsInodeInfo *cinode = CIFS_I(cfile->dentry->d_inode);



	xid = GetXid();

	tcon = tlink_tcon(cfile->tlink);



	mutex_lock(&cinode->lock_mutex);

	if (!cinode->can_cache_brlcks) {

		mutex_unlock(&cinode->lock_mutex);

		FreeXid(xid);

		return rc;

	}



	list_for_each_entry_safe(li, tmp, &cinode->llist, llist) {

		stored_rc = CIFSSMBLock(xid, tcon, cfile->netfid,

					li->pid, li->length, li->offset,

					0, 1, li->type, 0, 0);

		if (stored_rc)

			rc = stored_rc;

	}



	cinode->can_cache_brlcks = false;

	mutex_unlock(&cinode->lock_mutex);



	FreeXid(xid);

	return rc;

}



static void

cifs_read_flock(struct file_lock *flock, __u8 *type, int *lock, int *unlock,

		bool *wait_flag)
@@ -708,6 +870,7 @@ cifs_getlk(struct cifsFileInfo *cfile, struct file_lock *flock, __u8 type, 
{

	int rc = 0;

	__u64 length = 1 + flock->fl_end - flock->fl_start;

	struct cifsInodeInfo *cinode = CIFS_I(cfile->dentry->d_inode);

	__u16 netfid = cfile->netfid;

	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
@@ -723,6 +886,11 @@ cifs_getlk(struct cifsFileInfo *cfile, struct file_lock *flock, __u8 type, 
		return rc;

	}



	rc = cifs_lock_test(cinode, flock->fl_start, length, type, netfid,

			    flock);

	if (!rc)

		return rc;



	/* BB we could chain these into one lock request BB */

	rc = CIFSSMBLock(xid, tcon, netfid, current->tgid, length,

			 flock->fl_start, 0, 1, type, 0, 0);
@@ -790,11 +958,18 @@ cifs_setlk(struct file *file, struct file_lock *flock, __u8 type, 
	}



	if (lock) {

		rc = cifs_lock_add_if(cinode, flock->fl_start, length,

				      type, netfid, wait_flag);

		if (rc < 0)

			return rc;

		else if (!rc)

			goto out;



		rc = CIFSSMBLock(xid, tcon, netfid, current->tgid, length,

				 flock->fl_start, 0, lock, type, wait_flag, 0);

				 flock->fl_start, 0, 1, type, wait_flag, 0);

		if (rc == 0) {

			/* For Windows locks we must store them. */

			rc = store_file_lock(cinode, length, flock->fl_start,

			rc = cifs_lock_add(cinode, length, flock->fl_start,

					   type, netfid);

		}

	} else if (unlock) {
@@ -816,14 +991,19 @@ cifs_setlk(struct file *file, struct file_lock *flock, __u8 type, 
			if (cfile->netfid != li->netfid)

				continue;



			if (!cinode->can_cache_brlcks)

				stored_rc = CIFSSMBLock(xid, tcon, netfid,

						current->tgid, li->length,

						li->offset, 1, 0, li->type,

						0, 0);

							current->tgid,

							li->length, li->offset,

							1, 0, li->type, 0, 0);

			else

				stored_rc = 0;



			if (stored_rc)

				rc = stored_rc;

			else {

				list_del(&li->llist);

				cifs_del_lock_waiters(li);

				kfree(li);

			}

		}
@@ -2404,6 +2584,10 @@ void cifs_oplock_break(struct work_struct *work) 
		cFYI(1, "Oplock flush inode %p rc %d", inode, rc);

	}



	rc = cifs_push_locks(cfile);

	if (rc)

		cERROR(1, "Push locks rc = %d", rc);



	/*

	 * releasing stale oplock after recent reconnect of smb session using

	 * a now incorrect file handle is not a data integrity issue but do