1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Copyright (C) 2014 Facebook. All rights reserved. 4 */ 5 6 #ifndef BTRFS_QGROUP_H 7 #define BTRFS_QGROUP_H 8 9 #include <linux/spinlock.h> 10 #include <linux/rbtree.h> 11 #include "ulist.h" 12 #include "delayed-ref.h" 13 14 /* 15 * Btrfs qgroup overview 16 * 17 * Btrfs qgroup splits into 3 main part: 18 * 1) Reserve 19 * Reserve metadata/data space for incoming operations 20 * Affect how qgroup limit works 21 * 22 * 2) Trace 23 * Tell btrfs qgroup to trace dirty extents. 24 * 25 * Dirty extents including: 26 * - Newly allocated extents 27 * - Extents going to be deleted (in this trans) 28 * - Extents whose owner is going to be modified 29 * 30 * This is the main part affects whether qgroup numbers will stay 31 * consistent. 32 * Btrfs qgroup can trace clean extents and won't cause any problem, 33 * but it will consume extra CPU time, it should be avoided if possible. 34 * 35 * 3) Account 36 * Btrfs qgroup will updates its numbers, based on dirty extents traced 37 * in previous step. 38 * 39 * Normally at qgroup rescan and transaction commit time. 40 */ 41 42 /* 43 * Special performance optimization for balance. 44 * 45 * For balance, we need to swap subtree of subvolume and reloc trees. 46 * In theory, we need to trace all subtree blocks of both subvolume and reloc 47 * trees, since their owner has changed during such swap. 48 * 49 * However since balance has ensured that both subtrees are containing the 50 * same contents and have the same tree structures, such swap won't cause 51 * qgroup number change. 52 * 53 * But there is a race window between subtree swap and transaction commit, 54 * during that window, if we increase/decrease tree level or merge/split tree 55 * blocks, we still need to trace the original subtrees. 56 * 57 * So for balance, we use a delayed subtree tracing, whose workflow is: 58 * 59 * 1) Record the subtree root block get swapped. 60 * 61 * During subtree swap: 62 * O = Old tree blocks 63 * N = New tree blocks 64 * reloc tree subvolume tree X 65 * Root Root 66 * / \ / \ 67 * NA OB OA OB 68 * / | | \ / | | \ 69 * NC ND OE OF OC OD OE OF 70 * 71 * In this case, NA and OA are going to be swapped, record (NA, OA) into 72 * subvolume tree X. 73 * 74 * 2) After subtree swap. 75 * reloc tree subvolume tree X 76 * Root Root 77 * / \ / \ 78 * OA OB NA OB 79 * / | | \ / | | \ 80 * OC OD OE OF NC ND OE OF 81 * 82 * 3a) COW happens for OB 83 * If we are going to COW tree block OB, we check OB's bytenr against 84 * tree X's swapped_blocks structure. 85 * If it doesn't fit any, nothing will happen. 86 * 87 * 3b) COW happens for NA 88 * Check NA's bytenr against tree X's swapped_blocks, and get a hit. 89 * Then we do subtree scan on both subtrees OA and NA. 90 * Resulting 6 tree blocks to be scanned (OA, OC, OD, NA, NC, ND). 91 * 92 * Then no matter what we do to subvolume tree X, qgroup numbers will 93 * still be correct. 94 * Then NA's record gets removed from X's swapped_blocks. 95 * 96 * 4) Transaction commit 97 * Any record in X's swapped_blocks gets removed, since there is no 98 * modification to the swapped subtrees, no need to trigger heavy qgroup 99 * subtree rescan for them. 100 */ 101 102 /* 103 * Record a dirty extent, and info qgroup to update quota on it 104 * TODO: Use kmem cache to alloc it. 105 */ 106 struct btrfs_qgroup_extent_record { 107 struct rb_node node; 108 u64 bytenr; 109 u64 num_bytes; 110 111 /* 112 * For qgroup reserved data space freeing. 113 * 114 * @data_rsv_refroot and @data_rsv will be recorded after 115 * BTRFS_ADD_DELAYED_EXTENT is called. 116 * And will be used to free reserved qgroup space at 117 * transaction commit time. 118 */ 119 u32 data_rsv; /* reserved data space needs to be freed */ 120 u64 data_rsv_refroot; /* which root the reserved data belongs to */ 121 struct ulist *old_roots; 122 }; 123 124 struct btrfs_qgroup_swapped_block { 125 struct rb_node node; 126 127 int level; 128 bool trace_leaf; 129 130 /* bytenr/generation of the tree block in subvolume tree after swap */ 131 u64 subvol_bytenr; 132 u64 subvol_generation; 133 134 /* bytenr/generation of the tree block in reloc tree after swap */ 135 u64 reloc_bytenr; 136 u64 reloc_generation; 137 138 u64 last_snapshot; 139 struct btrfs_key first_key; 140 }; 141 142 /* 143 * Qgroup reservation types: 144 * 145 * DATA: 146 * space reserved for data 147 * 148 * META_PERTRANS: 149 * Space reserved for metadata (per-transaction) 150 * Due to the fact that qgroup data is only updated at transaction commit 151 * time, reserved space for metadata must be kept until transaction 152 * commits. 153 * Any metadata reserved that are used in btrfs_start_transaction() should 154 * be of this type. 155 * 156 * META_PREALLOC: 157 * There are cases where metadata space is reserved before starting 158 * transaction, and then btrfs_join_transaction() to get a trans handle. 159 * Any metadata reserved for such usage should be of this type. 160 * And after join_transaction() part (or all) of such reservation should 161 * be converted into META_PERTRANS. 162 */ 163 enum btrfs_qgroup_rsv_type { 164 BTRFS_QGROUP_RSV_DATA, 165 BTRFS_QGROUP_RSV_META_PERTRANS, 166 BTRFS_QGROUP_RSV_META_PREALLOC, 167 BTRFS_QGROUP_RSV_LAST, 168 }; 169 170 /* 171 * Represents how many bytes we have reserved for this qgroup. 172 * 173 * Each type should have different reservation behavior. 174 * E.g, data follows its io_tree flag modification, while 175 * *currently* meta is just reserve-and-clear during transaction. 176 * 177 * TODO: Add new type for reservation which can survive transaction commit. 178 * Current metadata reservation behavior is not suitable for such case. 179 */ 180 struct btrfs_qgroup_rsv { 181 u64 values[BTRFS_QGROUP_RSV_LAST]; 182 }; 183 184 /* 185 * one struct for each qgroup, organized in fs_info->qgroup_tree. 186 */ 187 struct btrfs_qgroup { 188 u64 qgroupid; 189 190 /* 191 * state 192 */ 193 u64 rfer; /* referenced */ 194 u64 rfer_cmpr; /* referenced compressed */ 195 u64 excl; /* exclusive */ 196 u64 excl_cmpr; /* exclusive compressed */ 197 198 /* 199 * limits 200 */ 201 u64 lim_flags; /* which limits are set */ 202 u64 max_rfer; 203 u64 max_excl; 204 u64 rsv_rfer; 205 u64 rsv_excl; 206 207 /* 208 * reservation tracking 209 */ 210 struct btrfs_qgroup_rsv rsv; 211 212 /* 213 * lists 214 */ 215 struct list_head groups; /* groups this group is member of */ 216 struct list_head members; /* groups that are members of this group */ 217 struct list_head dirty; /* dirty groups */ 218 struct rb_node node; /* tree of qgroups */ 219 220 /* 221 * temp variables for accounting operations 222 * Refer to qgroup_shared_accounting() for details. 223 */ 224 u64 old_refcnt; 225 u64 new_refcnt; 226 }; 227 228 /* 229 * For qgroup event trace points only 230 */ 231 #define QGROUP_RESERVE (1<<0) 232 #define QGROUP_RELEASE (1<<1) 233 #define QGROUP_FREE (1<<2) 234 235 int btrfs_quota_enable(struct btrfs_fs_info *fs_info); 236 int btrfs_quota_disable(struct btrfs_fs_info *fs_info); 237 int btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info); 238 void btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info); 239 int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info, 240 bool interruptible); 241 int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans, u64 src, 242 u64 dst); 243 int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src, 244 u64 dst); 245 int btrfs_create_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid); 246 int btrfs_remove_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid); 247 int btrfs_limit_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid, 248 struct btrfs_qgroup_limit *limit); 249 int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info); 250 void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info); 251 struct btrfs_delayed_extent_op; 252 253 /* 254 * Inform qgroup to trace one dirty extent, its info is recorded in @record. 255 * So qgroup can account it at transaction committing time. 256 * 257 * No lock version, caller must acquire delayed ref lock and allocated memory, 258 * then call btrfs_qgroup_trace_extent_post() after exiting lock context. 259 * 260 * Return 0 for success insert 261 * Return >0 for existing record, caller can free @record safely. 262 * Error is not possible 263 */ 264 int btrfs_qgroup_trace_extent_nolock( 265 struct btrfs_fs_info *fs_info, 266 struct btrfs_delayed_ref_root *delayed_refs, 267 struct btrfs_qgroup_extent_record *record); 268 269 /* 270 * Post handler after qgroup_trace_extent_nolock(). 271 * 272 * NOTE: Current qgroup does the expensive backref walk at transaction 273 * committing time with TRANS_STATE_COMMIT_DOING, this blocks incoming 274 * new transaction. 275 * This is designed to allow btrfs_find_all_roots() to get correct new_roots 276 * result. 277 * 278 * However for old_roots there is no need to do backref walk at that time, 279 * since we search commit roots to walk backref and result will always be 280 * correct. 281 * 282 * Due to the nature of no lock version, we can't do backref there. 283 * So we must call btrfs_qgroup_trace_extent_post() after exiting 284 * spinlock context. 285 * 286 * TODO: If we can fix and prove btrfs_find_all_roots() can get correct result 287 * using current root, then we can move all expensive backref walk out of 288 * transaction committing, but not now as qgroup accounting will be wrong again. 289 */ 290 int btrfs_qgroup_trace_extent_post(struct btrfs_fs_info *fs_info, 291 struct btrfs_qgroup_extent_record *qrecord); 292 293 /* 294 * Inform qgroup to trace one dirty extent, specified by @bytenr and 295 * @num_bytes. 296 * So qgroup can account it at commit trans time. 297 * 298 * Better encapsulated version, with memory allocation and backref walk for 299 * commit roots. 300 * So this can sleep. 301 * 302 * Return 0 if the operation is done. 303 * Return <0 for error, like memory allocation failure or invalid parameter 304 * (NULL trans) 305 */ 306 int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans, u64 bytenr, 307 u64 num_bytes, gfp_t gfp_flag); 308 309 /* 310 * Inform qgroup to trace all leaf items of data 311 * 312 * Return 0 for success 313 * Return <0 for error(ENOMEM) 314 */ 315 int btrfs_qgroup_trace_leaf_items(struct btrfs_trans_handle *trans, 316 struct extent_buffer *eb); 317 /* 318 * Inform qgroup to trace a whole subtree, including all its child tree 319 * blocks and data. 320 * The root tree block is specified by @root_eb. 321 * 322 * Normally used by relocation(tree block swap) and subvolume deletion. 323 * 324 * Return 0 for success 325 * Return <0 for error(ENOMEM or tree search error) 326 */ 327 int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans, 328 struct extent_buffer *root_eb, 329 u64 root_gen, int root_level); 330 int btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans, u64 bytenr, 331 u64 num_bytes, struct ulist *old_roots, 332 struct ulist *new_roots); 333 int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans); 334 int btrfs_run_qgroups(struct btrfs_trans_handle *trans); 335 int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid, 336 u64 objectid, struct btrfs_qgroup_inherit *inherit); 337 void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info, 338 u64 ref_root, u64 num_bytes, 339 enum btrfs_qgroup_rsv_type type); 340 341 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS 342 int btrfs_verify_qgroup_counts(struct btrfs_fs_info *fs_info, u64 qgroupid, 343 u64 rfer, u64 excl); 344 #endif 345 346 /* New io_tree based accurate qgroup reserve API */ 347 int btrfs_qgroup_reserve_data(struct inode *inode, 348 struct extent_changeset **reserved, u64 start, u64 len); 349 int btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len); 350 int btrfs_qgroup_free_data(struct inode *inode, 351 struct extent_changeset *reserved, u64 start, u64 len); 352 353 int __btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes, 354 enum btrfs_qgroup_rsv_type type, bool enforce); 355 /* Reserve metadata space for pertrans and prealloc type */ 356 static inline int btrfs_qgroup_reserve_meta_pertrans(struct btrfs_root *root, 357 int num_bytes, bool enforce) 358 { 359 return __btrfs_qgroup_reserve_meta(root, num_bytes, 360 BTRFS_QGROUP_RSV_META_PERTRANS, enforce); 361 } 362 static inline int btrfs_qgroup_reserve_meta_prealloc(struct btrfs_root *root, 363 int num_bytes, bool enforce) 364 { 365 return __btrfs_qgroup_reserve_meta(root, num_bytes, 366 BTRFS_QGROUP_RSV_META_PREALLOC, enforce); 367 } 368 369 void __btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes, 370 enum btrfs_qgroup_rsv_type type); 371 372 /* Free per-transaction meta reservation for error handling */ 373 static inline void btrfs_qgroup_free_meta_pertrans(struct btrfs_root *root, 374 int num_bytes) 375 { 376 __btrfs_qgroup_free_meta(root, num_bytes, 377 BTRFS_QGROUP_RSV_META_PERTRANS); 378 } 379 380 /* Pre-allocated meta reservation can be freed at need */ 381 static inline void btrfs_qgroup_free_meta_prealloc(struct btrfs_root *root, 382 int num_bytes) 383 { 384 __btrfs_qgroup_free_meta(root, num_bytes, 385 BTRFS_QGROUP_RSV_META_PREALLOC); 386 } 387 388 /* 389 * Per-transaction meta reservation should be all freed at transaction commit 390 * time 391 */ 392 void btrfs_qgroup_free_meta_all_pertrans(struct btrfs_root *root); 393 394 /* 395 * Convert @num_bytes of META_PREALLOCATED reservation to META_PERTRANS. 396 * 397 * This is called when preallocated meta reservation needs to be used. 398 * Normally after btrfs_join_transaction() call. 399 */ 400 void btrfs_qgroup_convert_reserved_meta(struct btrfs_root *root, int num_bytes); 401 402 void btrfs_qgroup_check_reserved_leak(struct inode *inode); 403 404 /* btrfs_qgroup_swapped_blocks related functions */ 405 void btrfs_qgroup_init_swapped_blocks( 406 struct btrfs_qgroup_swapped_blocks *swapped_blocks); 407 408 void btrfs_qgroup_clean_swapped_blocks(struct btrfs_root *root); 409 int btrfs_qgroup_add_swapped_blocks(struct btrfs_trans_handle *trans, 410 struct btrfs_root *subvol_root, 411 struct btrfs_block_group *bg, 412 struct extent_buffer *subvol_parent, int subvol_slot, 413 struct extent_buffer *reloc_parent, int reloc_slot, 414 u64 last_snapshot); 415 int btrfs_qgroup_trace_subtree_after_cow(struct btrfs_trans_handle *trans, 416 struct btrfs_root *root, struct extent_buffer *eb); 417 418 #endif 419