fs/btrfs/qgroup.h

   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 <linux/kobject.h>
  12 #include "ulist.h"
  13 #include "delayed-ref.h"
  14
  15 /*
  16  * Btrfs qgroup overview
  17  *
  18  * Btrfs qgroup splits into 3 main part:
  19  * 1) Reserve
  20  *    Reserve metadata/data space for incoming operations
  21  *    Affect how qgroup limit works
  22  *
  23  * 2) Trace
  24  *    Tell btrfs qgroup to trace dirty extents.
  25  *
  26  *    Dirty extents including:
  27  *    - Newly allocated extents
  28  *    - Extents going to be deleted (in this trans)
  29  *    - Extents whose owner is going to be modified
  30  *
  31  *    This is the main part affects whether qgroup numbers will stay
  32  *    consistent.
  33  *    Btrfs qgroup can trace clean extents and won't cause any problem,
  34  *    but it will consume extra CPU time, it should be avoided if possible.
  35  *
  36  * 3) Account
  37  *    Btrfs qgroup will updates its numbers, based on dirty extents traced
  38  *    in previous step.
  39  *
  40  *    Normally at qgroup rescan and transaction commit time.
  41  */
  42
  43 /*
  44  * Special performance optimization for balance.
  45  *
  46  * For balance, we need to swap subtree of subvolume and reloc trees.
  47  * In theory, we need to trace all subtree blocks of both subvolume and reloc
  48  * trees, since their owner has changed during such swap.
  49  *
  50  * However since balance has ensured that both subtrees are containing the
  51  * same contents and have the same tree structures, such swap won't cause
  52  * qgroup number change.
  53  *
  54  * But there is a race window between subtree swap and transaction commit,
  55  * during that window, if we increase/decrease tree level or merge/split tree
  56  * blocks, we still need to trace the original subtrees.
  57  *
  58  * So for balance, we use a delayed subtree tracing, whose workflow is:
  59  *
  60  * 1) Record the subtree root block get swapped.
  61  *
  62  *    During subtree swap:
  63  *    O = Old tree blocks
  64  *    N = New tree blocks
  65  *          reloc tree                     subvolume tree X
  66  *             Root                               Root
  67  *            /    \                             /    \
  68  *          NA     OB                          OA      OB
  69  *        /  |     |  \                      /  |      |  \
  70  *      NC  ND     OE  OF                   OC  OD     OE  OF
  71  *
  72  *   In this case, NA and OA are going to be swapped, record (NA, OA) into
  73  *   subvolume tree X.
  74  *
  75  * 2) After subtree swap.
  76  *          reloc tree                     subvolume tree X
  77  *             Root                               Root
  78  *            /    \                             /    \
  79  *          OA     OB                          NA      OB
  80  *        /  |     |  \                      /  |      |  \
  81  *      OC  OD     OE  OF                   NC  ND     OE  OF
  82  *
  83  * 3a) COW happens for OB
  84  *     If we are going to COW tree block OB, we check OB's bytenr against
  85  *     tree X's swapped_blocks structure.
  86  *     If it doesn't fit any, nothing will happen.
  87  *
  88  * 3b) COW happens for NA
  89  *     Check NA's bytenr against tree X's swapped_blocks, and get a hit.
  90  *     Then we do subtree scan on both subtrees OA and NA.
  91  *     Resulting 6 tree blocks to be scanned (OA, OC, OD, NA, NC, ND).
  92  *
  93  *     Then no matter what we do to subvolume tree X, qgroup numbers will
  94  *     still be correct.
  95  *     Then NA's record gets removed from X's swapped_blocks.
  96  *
  97  * 4)  Transaction commit
  98  *     Any record in X's swapped_blocks gets removed, since there is no
  99  *     modification to the swapped subtrees, no need to trigger heavy qgroup
 100  *     subtree rescan for them.
 101  */
 102
 103 /*
 104  * Record a dirty extent, and info qgroup to update quota on it
 105  * TODO: Use kmem cache to alloc it.
 106  */
 107 struct btrfs_qgroup_extent_record {
 108         struct rb_node node;
 109         u64 bytenr;
 110         u64 num_bytes;
 111
 112         /*
 113          * For qgroup reserved data space freeing.
 114          *
 115          * @data_rsv_refroot and @data_rsv will be recorded after
 116          * BTRFS_ADD_DELAYED_EXTENT is called.
 117          * And will be used to free reserved qgroup space at
 118          * transaction commit time.
 119          */
 120         u32 data_rsv;           /* reserved data space needs to be freed */
 121         u64 data_rsv_refroot;   /* which root the reserved data belongs to */
 122         struct ulist *old_roots;
 123 };
 124
 125 struct btrfs_qgroup_swapped_block {
 126         struct rb_node node;
 127
 128         int level;
 129         bool trace_leaf;
 130
 131         /* bytenr/generation of the tree block in subvolume tree after swap */
 132         u64 subvol_bytenr;
 133         u64 subvol_generation;
 134
 135         /* bytenr/generation of the tree block in reloc tree after swap */
 136         u64 reloc_bytenr;
 137         u64 reloc_generation;
 138
 139         u64 last_snapshot;
 140         struct btrfs_key first_key;
 141 };
 142
 143 /*
 144  * Qgroup reservation types:
 145  *
 146  * DATA:
 147  *      space reserved for data
 148  *
 149  * META_PERTRANS:
 150  *      Space reserved for metadata (per-transaction)
 151  *      Due to the fact that qgroup data is only updated at transaction commit
 152  *      time, reserved space for metadata must be kept until transaction
 153  *      commits.
 154  *      Any metadata reserved that are used in btrfs_start_transaction() should
 155  *      be of this type.
 156  *
 157  * META_PREALLOC:
 158  *      There are cases where metadata space is reserved before starting
 159  *      transaction, and then btrfs_join_transaction() to get a trans handle.
 160  *      Any metadata reserved for such usage should be of this type.
 161  *      And after join_transaction() part (or all) of such reservation should
 162  *      be converted into META_PERTRANS.
 163  */
 164 enum btrfs_qgroup_rsv_type {
 165         BTRFS_QGROUP_RSV_DATA,
 166         BTRFS_QGROUP_RSV_META_PERTRANS,
 167         BTRFS_QGROUP_RSV_META_PREALLOC,
 168         BTRFS_QGROUP_RSV_LAST,
 169 };
 170
 171 /*
 172  * Represents how many bytes we have reserved for this qgroup.
 173  *
 174  * Each type should have different reservation behavior.
 175  * E.g, data follows its io_tree flag modification, while
 176  * *currently* meta is just reserve-and-clear during transaction.
 177  *
 178  * TODO: Add new type for reservation which can survive transaction commit.
 179  * Current metadata reservation behavior is not suitable for such case.
 180  */
 181 struct btrfs_qgroup_rsv {
 182         u64 values[BTRFS_QGROUP_RSV_LAST];
 183 };
 184
 185 /*
 186  * one struct for each qgroup, organized in fs_info->qgroup_tree.
 187  */
 188 struct btrfs_qgroup {
 189         u64 qgroupid;
 190
 191         /*
 192          * state
 193          */
 194         u64 rfer;       /* referenced */
 195         u64 rfer_cmpr;  /* referenced compressed */
 196         u64 excl;       /* exclusive */
 197         u64 excl_cmpr;  /* exclusive compressed */
 198
 199         /*
 200          * limits
 201          */
 202         u64 lim_flags;  /* which limits are set */
 203         u64 max_rfer;
 204         u64 max_excl;
 205         u64 rsv_rfer;
 206         u64 rsv_excl;
 207
 208         /*
 209          * reservation tracking
 210          */
 211         struct btrfs_qgroup_rsv rsv;
 212
 213         /*
 214          * lists
 215          */
 216         struct list_head groups;  /* groups this group is member of */
 217         struct list_head members; /* groups that are members of this group */
 218         struct list_head dirty;   /* dirty groups */
 219         struct rb_node node;      /* tree of qgroups */
 220
 221         /*
 222          * temp variables for accounting operations
 223          * Refer to qgroup_shared_accounting() for details.
 224          */
 225         u64 old_refcnt;
 226         u64 new_refcnt;
 227
 228         /*
 229          * Sysfs kobjectid
 230          */
 231         struct kobject kobj;
 232 };
 233
 234 static inline u64 btrfs_qgroup_subvolid(u64 qgroupid)
 235 {
 236         return (qgroupid & ((1ULL << BTRFS_QGROUP_LEVEL_SHIFT) - 1));
 237 }
 238
 239 /*
 240  * For qgroup event trace points only
 241  */
 242 #define QGROUP_RESERVE          (1<<0)
 243 #define QGROUP_RELEASE          (1<<1)
 244 #define QGROUP_FREE             (1<<2)
 245
 246 int btrfs_quota_enable(struct btrfs_fs_info *fs_info);
 247 int btrfs_quota_disable(struct btrfs_fs_info *fs_info);
 248 int btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info);
 249 void btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info);
 250 int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info,
 251                                      bool interruptible);
 252 int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
 253                               u64 dst);
 254 int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
 255                               u64 dst);
 256 int btrfs_create_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid);
 257 int btrfs_remove_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid);
 258 int btrfs_limit_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid,
 259                        struct btrfs_qgroup_limit *limit);
 260 int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info);
 261 void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info);
 262 struct btrfs_delayed_extent_op;
 263
 264 /*
 265  * Inform qgroup to trace one dirty extent, its info is recorded in @record.
 266  * So qgroup can account it at transaction committing time.
 267  *
 268  * No lock version, caller must acquire delayed ref lock and allocated memory,
 269  * then call btrfs_qgroup_trace_extent_post() after exiting lock context.
 270  *
 271  * Return 0 for success insert
 272  * Return >0 for existing record, caller can free @record safely.
 273  * Error is not possible
 274  */
 275 int btrfs_qgroup_trace_extent_nolock(
 276                 struct btrfs_fs_info *fs_info,
 277                 struct btrfs_delayed_ref_root *delayed_refs,
 278                 struct btrfs_qgroup_extent_record *record);
 279
 280 /*
 281  * Post handler after qgroup_trace_extent_nolock().
 282  *
 283  * NOTE: Current qgroup does the expensive backref walk at transaction
 284  * committing time with TRANS_STATE_COMMIT_DOING, this blocks incoming
 285  * new transaction.
 286  * This is designed to allow btrfs_find_all_roots() to get correct new_roots
 287  * result.
 288  *
 289  * However for old_roots there is no need to do backref walk at that time,
 290  * since we search commit roots to walk backref and result will always be
 291  * correct.
 292  *
 293  * Due to the nature of no lock version, we can't do backref there.
 294  * So we must call btrfs_qgroup_trace_extent_post() after exiting
 295  * spinlock context.
 296  *
 297  * TODO: If we can fix and prove btrfs_find_all_roots() can get correct result
 298  * using current root, then we can move all expensive backref walk out of
 299  * transaction committing, but not now as qgroup accounting will be wrong again.
 300  */
 301 int btrfs_qgroup_trace_extent_post(struct btrfs_fs_info *fs_info,
 302                                    struct btrfs_qgroup_extent_record *qrecord);
 303
 304 /*
 305  * Inform qgroup to trace one dirty extent, specified by @bytenr and
 306  * @num_bytes.
 307  * So qgroup can account it at commit trans time.
 308  *
 309  * Better encapsulated version, with memory allocation and backref walk for
 310  * commit roots.
 311  * So this can sleep.
 312  *
 313  * Return 0 if the operation is done.
 314  * Return <0 for error, like memory allocation failure or invalid parameter
 315  * (NULL trans)
 316  */
 317 int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans, u64 bytenr,
 318                               u64 num_bytes, gfp_t gfp_flag);
 319
 320 /*
 321  * Inform qgroup to trace all leaf items of data
 322  *
 323  * Return 0 for success
 324  * Return <0 for error(ENOMEM)
 325  */
 326 int btrfs_qgroup_trace_leaf_items(struct btrfs_trans_handle *trans,
 327                                   struct extent_buffer *eb);
 328 /*
 329  * Inform qgroup to trace a whole subtree, including all its child tree
 330  * blocks and data.
 331  * The root tree block is specified by @root_eb.
 332  *
 333  * Normally used by relocation(tree block swap) and subvolume deletion.
 334  *
 335  * Return 0 for success
 336  * Return <0 for error(ENOMEM or tree search error)
 337  */
 338 int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
 339                                struct extent_buffer *root_eb,
 340                                u64 root_gen, int root_level);
 341 int btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans, u64 bytenr,
 342                                 u64 num_bytes, struct ulist *old_roots,
 343                                 struct ulist *new_roots);
 344 int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans);
 345 int btrfs_run_qgroups(struct btrfs_trans_handle *trans);
 346 int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
 347                          u64 objectid, struct btrfs_qgroup_inherit *inherit);
 348 void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info,
 349                                u64 ref_root, u64 num_bytes,
 350                                enum btrfs_qgroup_rsv_type type);
 351
 352 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 353 int btrfs_verify_qgroup_counts(struct btrfs_fs_info *fs_info, u64 qgroupid,
 354                                u64 rfer, u64 excl);
 355 #endif
 356
 357 /* New io_tree based accurate qgroup reserve API */
 358 int btrfs_qgroup_reserve_data(struct btrfs_inode *inode,
 359                         struct extent_changeset **reserved, u64 start, u64 len);
 360 int btrfs_qgroup_release_data(struct btrfs_inode *inode, u64 start, u64 len);
 361 int btrfs_qgroup_free_data(struct btrfs_inode *inode,
 362                            struct extent_changeset *reserved, u64 start,
 363                            u64 len);
 364 int __btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
 365                                 enum btrfs_qgroup_rsv_type type, bool enforce);
 366 /* Reserve metadata space for pertrans and prealloc type */
 367 static inline int btrfs_qgroup_reserve_meta_pertrans(struct btrfs_root *root,
 368                                 int num_bytes, bool enforce)
 369 {
 370         return __btrfs_qgroup_reserve_meta(root, num_bytes,
 371                         BTRFS_QGROUP_RSV_META_PERTRANS, enforce);
 372 }
 373 static inline int btrfs_qgroup_reserve_meta_prealloc(struct btrfs_root *root,
 374                                 int num_bytes, bool enforce)
 375 {
 376         return __btrfs_qgroup_reserve_meta(root, num_bytes,
 377                         BTRFS_QGROUP_RSV_META_PREALLOC, enforce);
 378 }
 379
 380 void __btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes,
 381                              enum btrfs_qgroup_rsv_type type);
 382
 383 /* Free per-transaction meta reservation for error handling */
 384 static inline void btrfs_qgroup_free_meta_pertrans(struct btrfs_root *root,
 385                                                    int num_bytes)
 386 {
 387         __btrfs_qgroup_free_meta(root, num_bytes,
 388                         BTRFS_QGROUP_RSV_META_PERTRANS);
 389 }
 390
 391 /* Pre-allocated meta reservation can be freed at need */
 392 static inline void btrfs_qgroup_free_meta_prealloc(struct btrfs_root *root,
 393                                                    int num_bytes)
 394 {
 395         __btrfs_qgroup_free_meta(root, num_bytes,
 396                         BTRFS_QGROUP_RSV_META_PREALLOC);
 397 }
 398
 399 /*
 400  * Per-transaction meta reservation should be all freed at transaction commit
 401  * time
 402  */
 403 void btrfs_qgroup_free_meta_all_pertrans(struct btrfs_root *root);
 404
 405 /*
 406  * Convert @num_bytes of META_PREALLOCATED reservation to META_PERTRANS.
 407  *
 408  * This is called when preallocated meta reservation needs to be used.
 409  * Normally after btrfs_join_transaction() call.
 410  */
 411 void btrfs_qgroup_convert_reserved_meta(struct btrfs_root *root, int num_bytes);
 412
 413 void btrfs_qgroup_check_reserved_leak(struct btrfs_inode *inode);
 414
 415 /* btrfs_qgroup_swapped_blocks related functions */
 416 void btrfs_qgroup_init_swapped_blocks(
 417         struct btrfs_qgroup_swapped_blocks *swapped_blocks);
 418
 419 void btrfs_qgroup_clean_swapped_blocks(struct btrfs_root *root);
 420 int btrfs_qgroup_add_swapped_blocks(struct btrfs_trans_handle *trans,
 421                 struct btrfs_root *subvol_root,
 422                 struct btrfs_block_group *bg,
 423                 struct extent_buffer *subvol_parent, int subvol_slot,
 424                 struct extent_buffer *reloc_parent, int reloc_slot,
 425                 u64 last_snapshot);
 426 int btrfs_qgroup_trace_subtree_after_cow(struct btrfs_trans_handle *trans,
 427                 struct btrfs_root *root, struct extent_buffer *eb);
 428 void btrfs_qgroup_destroy_extent_records(struct btrfs_transaction *trans);
 429 bool btrfs_check_quota_leak(struct btrfs_fs_info *fs_info);
 430
 431 #endif