diff options
Diffstat (limited to 'fs/btrfs/qgroup.h')
| -rw-r--r-- | fs/btrfs/qgroup.h | 120 |
1 files changed, 105 insertions, 15 deletions
diff --git a/fs/btrfs/qgroup.h b/fs/btrfs/qgroup.h index 20c6bd5fa701..46ba7bd2961c 100644 --- a/fs/btrfs/qgroup.h +++ b/fs/btrfs/qgroup.h @@ -6,6 +6,8 @@ #ifndef BTRFS_QGROUP_H #define BTRFS_QGROUP_H +#include <linux/spinlock.h> +#include <linux/rbtree.h> #include "ulist.h" #include "delayed-ref.h" @@ -38,6 +40,66 @@ */ /* + * Special performance optimization for balance. + * + * For balance, we need to swap subtree of subvolume and reloc trees. + * In theory, we need to trace all subtree blocks of both subvolume and reloc + * trees, since their owner has changed during such swap. + * + * However since balance has ensured that both subtrees are containing the + * same contents and have the same tree structures, such swap won't cause + * qgroup number change. + * + * But there is a race window between subtree swap and transaction commit, + * during that window, if we increase/decrease tree level or merge/split tree + * blocks, we still need to trace the original subtrees. + * + * So for balance, we use a delayed subtree tracing, whose workflow is: + * + * 1) Record the subtree root block get swapped. + * + * During subtree swap: + * O = Old tree blocks + * N = New tree blocks + * reloc tree subvolume tree X + * Root Root + * / \ / \ + * NA OB OA OB + * / | | \ / | | \ + * NC ND OE OF OC OD OE OF + * + * In this case, NA and OA are going to be swapped, record (NA, OA) into + * subvolume tree X. + * + * 2) After subtree swap. + * reloc tree subvolume tree X + * Root Root + * / \ / \ + * OA OB NA OB + * / | | \ / | | \ + * OC OD OE OF NC ND OE OF + * + * 3a) COW happens for OB + * If we are going to COW tree block OB, we check OB's bytenr against + * tree X's swapped_blocks structure. + * If it doesn't fit any, nothing will happen. + * + * 3b) COW happens for NA + * Check NA's bytenr against tree X's swapped_blocks, and get a hit. + * Then we do subtree scan on both subtrees OA and NA. + * Resulting 6 tree blocks to be scanned (OA, OC, OD, NA, NC, ND). + * + * Then no matter what we do to subvolume tree X, qgroup numbers will + * still be correct. + * Then NA's record gets removed from X's swapped_blocks. + * + * 4) Transaction commit + * Any record in X's swapped_blocks gets removed, since there is no + * modification to the swapped subtrees, no need to trigger heavy qgroup + * subtree rescan for them. + */ + +/* * Record a dirty extent, and info qgroup to update quota on it * TODO: Use kmem cache to alloc it. */ @@ -45,9 +107,38 @@ struct btrfs_qgroup_extent_record { struct rb_node node; u64 bytenr; u64 num_bytes; + + /* + * For qgroup reserved data space freeing. + * + * @data_rsv_refroot and @data_rsv will be recorded after + * BTRFS_ADD_DELAYED_EXTENT is called. + * And will be used to free reserved qgroup space at + * transaction commit time. + */ + u32 data_rsv; /* reserved data space needs to be freed */ + u64 data_rsv_refroot; /* which root the reserved data belongs to */ struct ulist *old_roots; }; +struct btrfs_qgroup_swapped_block { + struct rb_node node; + + int level; + bool trace_leaf; + + /* bytenr/generation of the tree block in subvolume tree after swap */ + u64 subvol_bytenr; + u64 subvol_generation; + + /* bytenr/generation of the tree block in reloc tree after swap */ + u64 reloc_bytenr; + u64 reloc_generation; + + u64 last_snapshot; + struct btrfs_key first_key; +}; + /* * Qgroup reservation types: * @@ -236,12 +327,6 @@ int btrfs_qgroup_trace_leaf_items(struct btrfs_trans_handle *trans, int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans, struct extent_buffer *root_eb, u64 root_gen, int root_level); - -int btrfs_qgroup_trace_subtree_swap(struct btrfs_trans_handle *trans, - struct btrfs_block_group_cache *bg_cache, - struct extent_buffer *src_parent, int src_slot, - struct extent_buffer *dst_parent, int dst_slot, - u64 last_snapshot); int btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans, u64 bytenr, u64 num_bytes, struct ulist *old_roots, struct ulist *new_roots); @@ -252,15 +337,6 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid, void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info, u64 ref_root, u64 num_bytes, enum btrfs_qgroup_rsv_type type); -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, - BTRFS_QGROUP_RSV_DATA); -} #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS int btrfs_verify_qgroup_counts(struct btrfs_fs_info *fs_info, u64 qgroupid, @@ -325,4 +401,18 @@ void btrfs_qgroup_convert_reserved_meta(struct btrfs_root *root, int num_bytes); void btrfs_qgroup_check_reserved_leak(struct inode *inode); +/* btrfs_qgroup_swapped_blocks related functions */ +void btrfs_qgroup_init_swapped_blocks( + struct btrfs_qgroup_swapped_blocks *swapped_blocks); + +void btrfs_qgroup_clean_swapped_blocks(struct btrfs_root *root); +int btrfs_qgroup_add_swapped_blocks(struct btrfs_trans_handle *trans, + struct btrfs_root *subvol_root, + struct btrfs_block_group_cache *bg, + struct extent_buffer *subvol_parent, int subvol_slot, + struct extent_buffer *reloc_parent, int reloc_slot, + u64 last_snapshot); +int btrfs_qgroup_trace_subtree_after_cow(struct btrfs_trans_handle *trans, + struct btrfs_root *root, struct extent_buffer *eb); + #endif |