#ifndef BTRFS_QGROUP_H
#define BTRFS_QGROUP_H
+#include <linux/spinlock.h>
+#include <linux/rbtree.h>
#include "ulist.h"
#include "delayed-ref.h"
* Normally at qgroup rescan and transaction commit time.
*/
+/*
+ * 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.
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:
*
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);
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,
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
projects / linux.git / blobdiff