#include <linux/ceph/ceph_debug.h>

  
  #include <linux/file.h>
  #include <linux/namei.h>

  #include <linux/random.h>

  
  #include "super.h"
  #include "mds_client.h"

  #include <linux/ceph/pagelist.h>

  static u64 lock_secret;

  static int ceph_lock_wait_for_completion(struct ceph_mds_client *mdsc,
                                           struct ceph_mds_request *req);

  
  static inline u64 secure_addr(void *addr)
  {
  	u64 v = lock_secret ^ (u64)(unsigned long)addr;
  	/*
  	 * Set the most significant bit, so that MDS knows the 'owner'
  	 * is sufficient to identify the owner of lock. (old code uses
  	 * both 'owner' and 'pid')
  	 */
  	v |= (1ULL << 63);
  	return v;
  }
  
  void __init ceph_flock_init(void)
  {
  	get_random_bytes(&lock_secret, sizeof(lock_secret));
  }

  /**
   * Implement fcntl and flock locking functions.
   */
  static int ceph_lock_message(u8 lock_type, u16 operation, struct file *file,

  			     int cmd, u8 wait, struct file_lock *fl)

  {

  	struct inode *inode = file_inode(file);

  	struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;

  	struct ceph_mds_request *req;
  	int err;

  	u64 length = 0;

  	u64 owner;

  	if (operation != CEPH_MDS_OP_SETFILELOCK || cmd == CEPH_LOCK_UNLOCK)
  		wait = 0;

  	req = ceph_mdsc_create_request(mdsc, operation, USE_AUTH_MDS);
  	if (IS_ERR(req))
  		return PTR_ERR(req);

  	req->r_inode = inode;
  	ihold(inode);

  	req->r_num_caps = 1;

  	/* mds requires start and length rather than start and end */
  	if (LLONG_MAX == fl->fl_end)
  		length = 0;
  	else
  		length = fl->fl_end - fl->fl_start + 1;

  	owner = secure_addr(fl->fl_owner);

  
  	dout("ceph_lock_message: rule: %d, op: %d, owner: %llx, pid: %llu, "
  	     "start: %llu, length: %llu, wait: %d, type: %d", (int)lock_type,
  	     (int)operation, owner, (u64)fl->fl_pid, fl->fl_start, length,
  	     wait, fl->fl_type);

  	req->r_args.filelock_change.rule = lock_type;
  	req->r_args.filelock_change.type = cmd;

  	req->r_args.filelock_change.owner = cpu_to_le64(owner);

  	req->r_args.filelock_change.pid = cpu_to_le64((u64)fl->fl_pid);

  	req->r_args.filelock_change.start = cpu_to_le64(fl->fl_start);

  	req->r_args.filelock_change.length = cpu_to_le64(length);
  	req->r_args.filelock_change.wait = wait;

  	if (wait)
  		req->r_wait_for_completion = ceph_lock_wait_for_completion;

  	err = ceph_mdsc_do_request(mdsc, inode, req);

  	if (operation == CEPH_MDS_OP_GETFILELOCK) {

  		fl->fl_pid = le64_to_cpu(req->r_reply_info.filelock_reply->pid);
  		if (CEPH_LOCK_SHARED == req->r_reply_info.filelock_reply->type)
  			fl->fl_type = F_RDLCK;
  		else if (CEPH_LOCK_EXCL == req->r_reply_info.filelock_reply->type)
  			fl->fl_type = F_WRLCK;
  		else
  			fl->fl_type = F_UNLCK;
  
  		fl->fl_start = le64_to_cpu(req->r_reply_info.filelock_reply->start);
  		length = le64_to_cpu(req->r_reply_info.filelock_reply->start) +
  						 le64_to_cpu(req->r_reply_info.filelock_reply->length);
  		if (length >= 1)
  			fl->fl_end = length -1;
  		else
  			fl->fl_end = 0;
  
  	}

  	ceph_mdsc_put_request(req);
  	dout("ceph_lock_message: rule: %d, op: %d, pid: %llu, start: %llu, "

  	     "length: %llu, wait: %d, type: %d, err code %d", (int)lock_type,

  	     (int)operation, (u64)fl->fl_pid, fl->fl_start,
  	     length, wait, fl->fl_type, err);

  	return err;
  }

  static int ceph_lock_wait_for_completion(struct ceph_mds_client *mdsc,
                                           struct ceph_mds_request *req)
  {
  	struct ceph_mds_request *intr_req;
  	struct inode *inode = req->r_inode;
  	int err, lock_type;
  
  	BUG_ON(req->r_op != CEPH_MDS_OP_SETFILELOCK);
  	if (req->r_args.filelock_change.rule == CEPH_LOCK_FCNTL)
  		lock_type = CEPH_LOCK_FCNTL_INTR;
  	else if (req->r_args.filelock_change.rule == CEPH_LOCK_FLOCK)
  		lock_type = CEPH_LOCK_FLOCK_INTR;
  	else
  		BUG_ON(1);
  	BUG_ON(req->r_args.filelock_change.type == CEPH_LOCK_UNLOCK);
  
  	err = wait_for_completion_interruptible(&req->r_completion);
  	if (!err)
  		return 0;
  
  	dout("ceph_lock_wait_for_completion: request %llu was interrupted
  ",
  	     req->r_tid);
  
  	intr_req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SETFILELOCK,
  					    USE_AUTH_MDS);
  	if (IS_ERR(intr_req))
  		return PTR_ERR(intr_req);
  
  	intr_req->r_inode = inode;
  	ihold(inode);
  	intr_req->r_num_caps = 1;
  
  	intr_req->r_args.filelock_change = req->r_args.filelock_change;
  	intr_req->r_args.filelock_change.rule = lock_type;
  	intr_req->r_args.filelock_change.type = CEPH_LOCK_UNLOCK;
  
  	err = ceph_mdsc_do_request(mdsc, inode, intr_req);
  	ceph_mdsc_put_request(intr_req);
  
  	if (err && err != -ERESTARTSYS)
  		return err;
  
  	wait_for_completion(&req->r_completion);
  	return 0;
  }

  /**
   * Attempt to set an fcntl lock.
   * For now, this just goes away to the server. Later it may be more awesome.
   */
  int ceph_lock(struct file *file, int cmd, struct file_lock *fl)
  {

  	u8 lock_cmd;
  	int err;
  	u8 wait = 0;
  	u16 op = CEPH_MDS_OP_SETFILELOCK;

  	if (!(fl->fl_flags & FL_POSIX))
  		return -ENOLCK;
  	/* No mandatory locks */
  	if (__mandatory_lock(file->f_mapping->host) && fl->fl_type != F_UNLCK)
  		return -ENOLCK;

  	dout("ceph_lock, fl_owner: %p", fl->fl_owner);

  
  	/* set wait bit as appropriate, then make command as Ceph expects it*/

  	if (IS_GETLK(cmd))

  		op = CEPH_MDS_OP_GETFILELOCK;

  	else if (IS_SETLKW(cmd))
  		wait = 1;

  
  	if (F_RDLCK == fl->fl_type)
  		lock_cmd = CEPH_LOCK_SHARED;
  	else if (F_WRLCK == fl->fl_type)
  		lock_cmd = CEPH_LOCK_EXCL;
  	else
  		lock_cmd = CEPH_LOCK_UNLOCK;

  	err = ceph_lock_message(CEPH_LOCK_FCNTL, op, file, lock_cmd, wait, fl);

  	if (!err) {

  		if (op != CEPH_MDS_OP_GETFILELOCK) {

  			dout("mds locked, locking locally");
  			err = posix_lock_file(file, fl, NULL);
  			if (err && (CEPH_MDS_OP_SETFILELOCK == op)) {

  				/* undo! This should only happen if
  				 * the kernel detects local
  				 * deadlock. */

  				ceph_lock_message(CEPH_LOCK_FCNTL, op, file,
  						  CEPH_LOCK_UNLOCK, 0, fl);

  				dout("got %d on posix_lock_file, undid lock",
  				     err);

  			}

  		}

  	}
  	return err;
  }
  
  int ceph_flock(struct file *file, int cmd, struct file_lock *fl)
  {

  	u8 lock_cmd;
  	int err;

  	u8 wait = 0;

  	if (!(fl->fl_flags & FL_FLOCK))
  		return -ENOLCK;
  	/* No mandatory locks */
  	if (__mandatory_lock(file->f_mapping->host) && fl->fl_type != F_UNLCK)
  		return -ENOLCK;

  	dout("ceph_flock, fl_file: %p", fl->fl_file);

  	if (IS_SETLKW(cmd))
  		wait = 1;
  
  	if (F_RDLCK == fl->fl_type)

  		lock_cmd = CEPH_LOCK_SHARED;

  	else if (F_WRLCK == fl->fl_type)

  		lock_cmd = CEPH_LOCK_EXCL;
  	else
  		lock_cmd = CEPH_LOCK_UNLOCK;

  
  	err = ceph_lock_message(CEPH_LOCK_FLOCK, CEPH_MDS_OP_SETFILELOCK,

  				file, lock_cmd, wait, fl);

  	if (!err) {

  		err = locks_lock_file_wait(file, fl);

  		if (err) {
  			ceph_lock_message(CEPH_LOCK_FLOCK,
  					  CEPH_MDS_OP_SETFILELOCK,

  					  file, CEPH_LOCK_UNLOCK, 0, fl);

  			dout("got %d on locks_lock_file_wait, undid lock", err);

  		}

  	}
  	return err;
  }

  /*
   * Fills in the passed counter variables, so you can prepare pagelist metadata
   * before calling ceph_encode_locks.

   */
  void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count)
  {

  	struct file_lock *lock;

  	struct file_lock_context *ctx;

  
  	*fcntl_count = 0;
  	*flock_count = 0;

  	ctx = inode->i_flctx;
  	if (ctx) {

  		spin_lock(&ctx->flc_lock);
  		list_for_each_entry(lock, &ctx->flc_posix, fl_list)
  			++(*fcntl_count);
  		list_for_each_entry(lock, &ctx->flc_flock, fl_list)
  			++(*flock_count);
  		spin_unlock(&ctx->flc_lock);

  	}
  	dout("counted %d flock locks and %d fcntl locks",
  	     *flock_count, *fcntl_count);
  }
  
  /**

   * Encode the flock and fcntl locks for the given inode into the ceph_filelock

   * array. Must be called with inode->i_lock already held.

   * If we encounter more of a specific lock type than expected, return -ENOSPC.

   */

  int ceph_encode_locks_to_buffer(struct inode *inode,
  				struct ceph_filelock *flocks,
  				int num_fcntl_locks, int num_flock_locks)

  {
  	struct file_lock *lock;

  	struct file_lock_context *ctx = inode->i_flctx;

  	int err = 0;

  	int seen_fcntl = 0;
  	int seen_flock = 0;

  	int l = 0;

  
  	dout("encoding %d flock and %d fcntl locks", num_flock_locks,
  	     num_fcntl_locks);

  	if (!ctx)
  		return 0;

  	spin_lock(&ctx->flc_lock);

  	list_for_each_entry(lock, &ctx->flc_posix, fl_list) {

  		++seen_fcntl;
  		if (seen_fcntl > num_fcntl_locks) {
  			err = -ENOSPC;
  			goto fail;

  		}

  		err = lock_to_ceph_filelock(lock, &flocks[l]);
  		if (err)
  			goto fail;
  		++l;

  	}

  	list_for_each_entry(lock, &ctx->flc_flock, fl_list) {
  		++seen_flock;
  		if (seen_flock > num_flock_locks) {
  			err = -ENOSPC;
  			goto fail;

  		}

  		err = lock_to_ceph_filelock(lock, &flocks[l]);
  		if (err)
  			goto fail;
  		++l;

  	}
  fail:

  	spin_unlock(&ctx->flc_lock);

  	return err;
  }

  /**
   * Copy the encoded flock and fcntl locks into the pagelist.
   * Format is: #fcntl locks, sequential fcntl locks, #flock locks,
   * sequential flock locks.
   * Returns zero on success.
   */
  int ceph_locks_to_pagelist(struct ceph_filelock *flocks,
  			   struct ceph_pagelist *pagelist,
  			   int num_fcntl_locks, int num_flock_locks)
  {
  	int err = 0;
  	__le32 nlocks;
  
  	nlocks = cpu_to_le32(num_fcntl_locks);
  	err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks));
  	if (err)
  		goto out_fail;
  
  	err = ceph_pagelist_append(pagelist, flocks,
  				   num_fcntl_locks * sizeof(*flocks));
  	if (err)
  		goto out_fail;
  
  	nlocks = cpu_to_le32(num_flock_locks);
  	err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks));
  	if (err)
  		goto out_fail;
  
  	err = ceph_pagelist_append(pagelist,
  				   &flocks[num_fcntl_locks],
  				   num_flock_locks * sizeof(*flocks));
  out_fail:
  	return err;
  }

  /*
   * Given a pointer to a lock, convert it to a ceph filelock
   */
  int lock_to_ceph_filelock(struct file_lock *lock,
  			  struct ceph_filelock *cephlock)
  {
  	int err = 0;

  	cephlock->start = cpu_to_le64(lock->fl_start);
  	cephlock->length = cpu_to_le64(lock->fl_end - lock->fl_start + 1);
  	cephlock->client = cpu_to_le64(0);

  	cephlock->pid = cpu_to_le64((u64)lock->fl_pid);

  	cephlock->owner = cpu_to_le64(secure_addr(lock->fl_owner));

  
  	switch (lock->fl_type) {
  	case F_RDLCK:
  		cephlock->type = CEPH_LOCK_SHARED;
  		break;
  	case F_WRLCK:
  		cephlock->type = CEPH_LOCK_EXCL;
  		break;
  	case F_UNLCK:
  		cephlock->type = CEPH_LOCK_UNLOCK;
  		break;
  	default:
  		dout("Have unknown lock type %d", lock->fl_type);
  		err = -EINVAL;
  	}
  
  	return err;
  }