/*
   * Copyright (C) 2014 Facebook.  All rights reserved.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public
   * License v2 as published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License for more details.
   *
   * You should have received a copy of the GNU General Public
   * License along with this program; if not, write to the
   * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   * Boston, MA 021110-1307, USA.
   */
  
  #ifndef __BTRFS_QGROUP__
  #define __BTRFS_QGROUP__

  #include "ulist.h"
  #include "delayed-ref.h"

  /*

   * Btrfs qgroup overview
   *
   * Btrfs qgroup splits into 3 main part:
   * 1) Reserve
   *    Reserve metadata/data space for incoming operations
   *    Affect how qgroup limit works
   *
   * 2) Trace
   *    Tell btrfs qgroup to trace dirty extents.
   *
   *    Dirty extents including:
   *    - Newly allocated extents
   *    - Extents going to be deleted (in this trans)
   *    - Extents whose owner is going to be modified
   *
   *    This is the main part affects whether qgroup numbers will stay
   *    consistent.
   *    Btrfs qgroup can trace clean extents and won't cause any problem,
   *    but it will consume extra CPU time, it should be avoided if possible.
   *
   * 3) Account
   *    Btrfs qgroup will updates its numbers, based on dirty extents traced
   *    in previous step.
   *
   *    Normally at qgroup rescan and transaction commit time.
   */
  
  /*

   * Record a dirty extent, and info qgroup to update quota on it
   * TODO: Use kmem cache to alloc it.
   */
  struct btrfs_qgroup_extent_record {
  	struct rb_node node;
  	u64 bytenr;
  	u64 num_bytes;
  	struct ulist *old_roots;
  };

  /*

   * one struct for each qgroup, organized in fs_info->qgroup_tree.
   */
  struct btrfs_qgroup {
  	u64 qgroupid;
  
  	/*
  	 * state
  	 */
  	u64 rfer;	/* referenced */
  	u64 rfer_cmpr;	/* referenced compressed */
  	u64 excl;	/* exclusive */
  	u64 excl_cmpr;	/* exclusive compressed */
  
  	/*
  	 * limits
  	 */
  	u64 lim_flags;	/* which limits are set */
  	u64 max_rfer;
  	u64 max_excl;
  	u64 rsv_rfer;
  	u64 rsv_excl;
  
  	/*
  	 * reservation tracking
  	 */
  	u64 reserved;
  
  	/*
  	 * lists
  	 */
  	struct list_head groups;  /* groups this group is member of */
  	struct list_head members; /* groups that are members of this group */
  	struct list_head dirty;   /* dirty groups */
  	struct rb_node node;	  /* tree of qgroups */
  
  	/*
  	 * temp variables for accounting operations
  	 * Refer to qgroup_shared_accounting() for details.
  	 */
  	u64 old_refcnt;
  	u64 new_refcnt;
  };
  
  /*

   * For qgroup event trace points only
   */
  #define QGROUP_RESERVE		(1<<0)
  #define QGROUP_RELEASE		(1<<1)
  #define QGROUP_FREE		(1<<2)

  int btrfs_quota_enable(struct btrfs_trans_handle *trans,
  		       struct btrfs_fs_info *fs_info);
  int btrfs_quota_disable(struct btrfs_trans_handle *trans,
  			struct btrfs_fs_info *fs_info);
  int btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info);
  void btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info);

  int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info,
  				     bool interruptible);

  int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans,
  			      struct btrfs_fs_info *fs_info, u64 src, u64 dst);
  int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans,
  			      struct btrfs_fs_info *fs_info, u64 src, u64 dst);
  int btrfs_create_qgroup(struct btrfs_trans_handle *trans,

  			struct btrfs_fs_info *fs_info, u64 qgroupid);

  int btrfs_remove_qgroup(struct btrfs_trans_handle *trans,
  			      struct btrfs_fs_info *fs_info, u64 qgroupid);
  int btrfs_limit_qgroup(struct btrfs_trans_handle *trans,
  		       struct btrfs_fs_info *fs_info, u64 qgroupid,
  		       struct btrfs_qgroup_limit *limit);
  int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info);
  void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info);
  struct btrfs_delayed_extent_op;

  /*

   * Inform qgroup to trace one dirty extent, its info is recorded in @record.

   * So qgroup can account it at transaction committing time.

   *

   * No lock version, caller must acquire delayed ref lock and allocated memory,
   * then call btrfs_qgroup_trace_extent_post() after exiting lock context.

   *
   * Return 0 for success insert
   * Return >0 for existing record, caller can free @record safely.
   * Error is not possible
   */

  int btrfs_qgroup_trace_extent_nolock(

  		struct btrfs_fs_info *fs_info,
  		struct btrfs_delayed_ref_root *delayed_refs,
  		struct btrfs_qgroup_extent_record *record);
  
  /*

   * Post handler after qgroup_trace_extent_nolock().
   *
   * NOTE: Current qgroup does the expensive backref walk at transaction
   * committing time with TRANS_STATE_COMMIT_DOING, this blocks incoming
   * new transaction.
   * This is designed to allow btrfs_find_all_roots() to get correct new_roots
   * result.
   *
   * However for old_roots there is no need to do backref walk at that time,
   * since we search commit roots to walk backref and result will always be
   * correct.
   *
   * Due to the nature of no lock version, we can't do backref there.
   * So we must call btrfs_qgroup_trace_extent_post() after exiting
   * spinlock context.
   *
   * TODO: If we can fix and prove btrfs_find_all_roots() can get correct result
   * using current root, then we can move all expensive backref walk out of
   * transaction committing, but not now as qgroup accounting will be wrong again.
   */
  int btrfs_qgroup_trace_extent_post(struct btrfs_fs_info *fs_info,
  				   struct btrfs_qgroup_extent_record *qrecord);
  
  /*

   * Inform qgroup to trace one dirty extent, specified by @bytenr and
   * @num_bytes.
   * So qgroup can account it at commit trans time.

   *

   * Better encapsulated version, with memory allocation and backref walk for
   * commit roots.
   * So this can sleep.

   *
   * Return 0 if the operation is done.
   * Return <0 for error, like memory allocation failure or invalid parameter
   * (NULL trans)
   */

  int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans,

  		struct btrfs_fs_info *fs_info, u64 bytenr, u64 num_bytes,
  		gfp_t gfp_flag);

  /*
   * Inform qgroup to trace all leaf items of data
   *
   * Return 0 for success
   * Return <0 for error(ENOMEM)
   */
  int btrfs_qgroup_trace_leaf_items(struct btrfs_trans_handle *trans,

  				  struct btrfs_fs_info *fs_info,

  				  struct extent_buffer *eb);
  /*
   * Inform qgroup to trace a whole subtree, including all its child tree
   * blocks and data.
   * The root tree block is specified by @root_eb.
   *
   * Normally used by relocation(tree block swap) and subvolume deletion.
   *
   * Return 0 for success
   * Return <0 for error(ENOMEM or tree search error)
   */
  int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
  			       struct btrfs_root *root,
  			       struct extent_buffer *root_eb,
  			       u64 root_gen, int root_level);

  int
  btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans,
  			    struct btrfs_fs_info *fs_info,
  			    u64 bytenr, u64 num_bytes,
  			    struct ulist *old_roots, struct ulist *new_roots);

  int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans,
  				 struct btrfs_fs_info *fs_info);

  int btrfs_run_qgroups(struct btrfs_trans_handle *trans,
  		      struct btrfs_fs_info *fs_info);
  int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans,
  			 struct btrfs_fs_info *fs_info, u64 srcid, u64 objectid,
  			 struct btrfs_qgroup_inherit *inherit);

  void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info,
  			       u64 ref_root, u64 num_bytes);

  static inline void btrfs_qgroup_free_delayed_ref(struct btrfs_fs_info *fs_info,
  						 u64 ref_root, u64 num_bytes)
  {

  	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
  		return;

  	trace_btrfs_qgroup_free_delayed_ref(fs_info, ref_root, num_bytes);

  	btrfs_qgroup_free_refroot(fs_info, ref_root, num_bytes);

  }

  
  #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
  int btrfs_verify_qgroup_counts(struct btrfs_fs_info *fs_info, u64 qgroupid,
  			       u64 rfer, u64 excl);
  #endif

  /* New io_tree based accurate qgroup reserve API */

  int btrfs_qgroup_reserve_data(struct inode *inode,
  			struct extent_changeset **reserved, u64 start, u64 len);

  int btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len);

  int btrfs_qgroup_free_data(struct inode *inode,
  			struct extent_changeset *reserved, u64 start, u64 len);

  int btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
  			      bool enforce);

  void btrfs_qgroup_free_meta_all(struct btrfs_root *root);
  void btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes);

  void btrfs_qgroup_check_reserved_leak(struct inode *inode);

  #endif /* __BTRFS_QGROUP__ */