cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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qgroup.h (14548B)


      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 */
    107struct 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
    125struct 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 */
    164enum 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 */
    181struct 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 */
    188struct 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
    234static 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
    246int btrfs_quota_enable(struct btrfs_fs_info *fs_info);
    247int btrfs_quota_disable(struct btrfs_fs_info *fs_info);
    248int btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info);
    249void btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info);
    250int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info,
    251				     bool interruptible);
    252int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
    253			      u64 dst);
    254int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
    255			      u64 dst);
    256int btrfs_create_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid);
    257int btrfs_remove_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid);
    258int btrfs_limit_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid,
    259		       struct btrfs_qgroup_limit *limit);
    260int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info);
    261void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info);
    262struct 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 */
    275int 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 */
    301int btrfs_qgroup_trace_extent_post(struct btrfs_trans_handle *trans,
    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 */
    317int 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 */
    326int 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 */
    338int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
    339			       struct extent_buffer *root_eb,
    340			       u64 root_gen, int root_level);
    341int btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans, u64 bytenr,
    342				u64 num_bytes, struct ulist *old_roots,
    343				struct ulist *new_roots);
    344int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans);
    345int btrfs_run_qgroups(struct btrfs_trans_handle *trans);
    346int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
    347			 u64 objectid, struct btrfs_qgroup_inherit *inherit);
    348void 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
    353int 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 */
    358int btrfs_qgroup_reserve_data(struct btrfs_inode *inode,
    359			struct extent_changeset **reserved, u64 start, u64 len);
    360int btrfs_qgroup_release_data(struct btrfs_inode *inode, u64 start, u64 len);
    361int btrfs_qgroup_free_data(struct btrfs_inode *inode,
    362			   struct extent_changeset *reserved, u64 start,
    363			   u64 len);
    364int btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
    365			      enum btrfs_qgroup_rsv_type type, bool enforce);
    366int __btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
    367				enum btrfs_qgroup_rsv_type type, bool enforce,
    368				bool noflush);
    369/* Reserve metadata space for pertrans and prealloc type */
    370static inline int btrfs_qgroup_reserve_meta_pertrans(struct btrfs_root *root,
    371				int num_bytes, bool enforce)
    372{
    373	return __btrfs_qgroup_reserve_meta(root, num_bytes,
    374					   BTRFS_QGROUP_RSV_META_PERTRANS,
    375					   enforce, false);
    376}
    377static inline int btrfs_qgroup_reserve_meta_prealloc(struct btrfs_root *root,
    378						     int num_bytes, bool enforce,
    379						     bool noflush)
    380{
    381	return __btrfs_qgroup_reserve_meta(root, num_bytes,
    382					   BTRFS_QGROUP_RSV_META_PREALLOC,
    383					   enforce, noflush);
    384}
    385
    386void __btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes,
    387			     enum btrfs_qgroup_rsv_type type);
    388
    389/* Free per-transaction meta reservation for error handling */
    390static inline void btrfs_qgroup_free_meta_pertrans(struct btrfs_root *root,
    391						   int num_bytes)
    392{
    393	__btrfs_qgroup_free_meta(root, num_bytes,
    394			BTRFS_QGROUP_RSV_META_PERTRANS);
    395}
    396
    397/* Pre-allocated meta reservation can be freed at need */
    398static inline void btrfs_qgroup_free_meta_prealloc(struct btrfs_root *root,
    399						   int num_bytes)
    400{
    401	__btrfs_qgroup_free_meta(root, num_bytes,
    402			BTRFS_QGROUP_RSV_META_PREALLOC);
    403}
    404
    405/*
    406 * Per-transaction meta reservation should be all freed at transaction commit
    407 * time
    408 */
    409void btrfs_qgroup_free_meta_all_pertrans(struct btrfs_root *root);
    410
    411/*
    412 * Convert @num_bytes of META_PREALLOCATED reservation to META_PERTRANS.
    413 *
    414 * This is called when preallocated meta reservation needs to be used.
    415 * Normally after btrfs_join_transaction() call.
    416 */
    417void btrfs_qgroup_convert_reserved_meta(struct btrfs_root *root, int num_bytes);
    418
    419void btrfs_qgroup_check_reserved_leak(struct btrfs_inode *inode);
    420
    421/* btrfs_qgroup_swapped_blocks related functions */
    422void btrfs_qgroup_init_swapped_blocks(
    423	struct btrfs_qgroup_swapped_blocks *swapped_blocks);
    424
    425void btrfs_qgroup_clean_swapped_blocks(struct btrfs_root *root);
    426int btrfs_qgroup_add_swapped_blocks(struct btrfs_trans_handle *trans,
    427		struct btrfs_root *subvol_root,
    428		struct btrfs_block_group *bg,
    429		struct extent_buffer *subvol_parent, int subvol_slot,
    430		struct extent_buffer *reloc_parent, int reloc_slot,
    431		u64 last_snapshot);
    432int btrfs_qgroup_trace_subtree_after_cow(struct btrfs_trans_handle *trans,
    433		struct btrfs_root *root, struct extent_buffer *eb);
    434void btrfs_qgroup_destroy_extent_records(struct btrfs_transaction *trans);
    435bool btrfs_check_quota_leak(struct btrfs_fs_info *fs_info);
    436
    437#endif