btrfs: qgroup: Add comments explaining how btrfs qgroup works
[linux-2.6-block.git] / fs / btrfs / qgroup.h
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1/*
2 * Copyright (C) 2014 Facebook. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19#ifndef __BTRFS_QGROUP__
20#define __BTRFS_QGROUP__
21
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22#include "ulist.h"
23#include "delayed-ref.h"
24
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25/*
26 * Btrfs qgroup overview
27 *
28 * Btrfs qgroup splits into 3 main part:
29 * 1) Reserve
30 * Reserve metadata/data space for incoming operations
31 * Affect how qgroup limit works
32 *
33 * 2) Trace
34 * Tell btrfs qgroup to trace dirty extents.
35 *
36 * Dirty extents including:
37 * - Newly allocated extents
38 * - Extents going to be deleted (in this trans)
39 * - Extents whose owner is going to be modified
40 *
41 * This is the main part affects whether qgroup numbers will stay
42 * consistent.
43 * Btrfs qgroup can trace clean extents and won't cause any problem,
44 * but it will consume extra CPU time, it should be avoided if possible.
45 *
46 * 3) Account
47 * Btrfs qgroup will updates its numbers, based on dirty extents traced
48 * in previous step.
49 *
50 * Normally at qgroup rescan and transaction commit time.
51 */
52
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53/*
54 * Record a dirty extent, and info qgroup to update quota on it
55 * TODO: Use kmem cache to alloc it.
56 */
57struct btrfs_qgroup_extent_record {
58 struct rb_node node;
59 u64 bytenr;
60 u64 num_bytes;
61 struct ulist *old_roots;
62};
63
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64/*
65 * For qgroup event trace points only
66 */
67#define QGROUP_RESERVE (1<<0)
68#define QGROUP_RELEASE (1<<1)
69#define QGROUP_FREE (1<<2)
70
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71int btrfs_quota_enable(struct btrfs_trans_handle *trans,
72 struct btrfs_fs_info *fs_info);
73int btrfs_quota_disable(struct btrfs_trans_handle *trans,
74 struct btrfs_fs_info *fs_info);
75int btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info);
76void btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info);
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77int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info,
78 bool interruptible);
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79int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans,
80 struct btrfs_fs_info *fs_info, u64 src, u64 dst);
81int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans,
82 struct btrfs_fs_info *fs_info, u64 src, u64 dst);
83int btrfs_create_qgroup(struct btrfs_trans_handle *trans,
4087cf24 84 struct btrfs_fs_info *fs_info, u64 qgroupid);
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85int btrfs_remove_qgroup(struct btrfs_trans_handle *trans,
86 struct btrfs_fs_info *fs_info, u64 qgroupid);
87int btrfs_limit_qgroup(struct btrfs_trans_handle *trans,
88 struct btrfs_fs_info *fs_info, u64 qgroupid,
89 struct btrfs_qgroup_limit *limit);
90int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info);
91void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info);
92struct btrfs_delayed_extent_op;
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93int btrfs_qgroup_prepare_account_extents(struct btrfs_trans_handle *trans,
94 struct btrfs_fs_info *fs_info);
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95/*
96 * Insert one dirty extent record into @delayed_refs, informing qgroup to
97 * account that extent at commit trans time.
98 *
99 * No lock version, caller must acquire delayed ref lock and allocate memory.
100 *
101 * Return 0 for success insert
102 * Return >0 for existing record, caller can free @record safely.
103 * Error is not possible
104 */
105int btrfs_qgroup_insert_dirty_extent_nolock(
106 struct btrfs_fs_info *fs_info,
107 struct btrfs_delayed_ref_root *delayed_refs,
108 struct btrfs_qgroup_extent_record *record);
109
110/*
111 * Insert one dirty extent record into @delayed_refs, informing qgroup to
112 * account that extent at commit trans time.
113 *
114 * Better encapsulated version.
115 *
116 * Return 0 if the operation is done.
117 * Return <0 for error, like memory allocation failure or invalid parameter
118 * (NULL trans)
119 */
120int btrfs_qgroup_insert_dirty_extent(struct btrfs_trans_handle *trans,
121 struct btrfs_fs_info *fs_info, u64 bytenr, u64 num_bytes,
122 gfp_t gfp_flag);
123
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124int
125btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans,
126 struct btrfs_fs_info *fs_info,
127 u64 bytenr, u64 num_bytes,
128 struct ulist *old_roots, struct ulist *new_roots);
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129int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans,
130 struct btrfs_fs_info *fs_info);
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131int btrfs_run_qgroups(struct btrfs_trans_handle *trans,
132 struct btrfs_fs_info *fs_info);
133int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans,
134 struct btrfs_fs_info *fs_info, u64 srcid, u64 objectid,
135 struct btrfs_qgroup_inherit *inherit);
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136void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info,
137 u64 ref_root, u64 num_bytes);
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138/*
139 * TODO: Add proper trace point for it, as btrfs_qgroup_free() is
140 * called by everywhere, can't provide good trace for delayed ref case.
141 */
142static inline void btrfs_qgroup_free_delayed_ref(struct btrfs_fs_info *fs_info,
143 u64 ref_root, u64 num_bytes)
144{
145 btrfs_qgroup_free_refroot(fs_info, ref_root, num_bytes);
bc074524 146 trace_btrfs_qgroup_free_delayed_ref(fs_info, ref_root, num_bytes);
297d750b 147}
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148void assert_qgroups_uptodate(struct btrfs_trans_handle *trans);
149
150#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
151int btrfs_verify_qgroup_counts(struct btrfs_fs_info *fs_info, u64 qgroupid,
152 u64 rfer, u64 excl);
153#endif
154
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155/* New io_tree based accurate qgroup reserve API */
156int btrfs_qgroup_reserve_data(struct inode *inode, u64 start, u64 len);
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157int btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len);
158int btrfs_qgroup_free_data(struct inode *inode, u64 start, u64 len);
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159
160int btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes);
161void btrfs_qgroup_free_meta_all(struct btrfs_root *root);
162void btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes);
56fa9d07 163void btrfs_qgroup_check_reserved_leak(struct inode *inode);
fcebe456 164#endif /* __BTRFS_QGROUP__ */