diff options
| -rw-r--r-- | Makefile | 3 | ||||
| -rw-r--r-- | ctree.h | 3 | ||||
| -rw-r--r-- | delayed-ref.c | 607 | ||||
| -rw-r--r-- | delayed-ref.h | 208 | ||||
| -rw-r--r-- | extent-tree.c | 226 | ||||
| -rw-r--r-- | kerncompat.h | 8 | ||||
| -rw-r--r-- | transaction.h | 4 |
7 files changed, 1058 insertions, 1 deletions
@@ -116,7 +116,8 @@ objects = ctree.o disk-io.o kernel-lib/radix-tree.o extent-tree.o print-tree.o \ qgroup.o free-space-cache.o kernel-lib/list_sort.o props.o \ kernel-shared/ulist.o qgroup-verify.o backref.o string-table.o task-utils.o \ inode.o file.o find-root.o free-space-tree.o help.o send-dump.o \ - fsfeatures.o kernel-lib/tables.o kernel-lib/raid56.o transaction.o + fsfeatures.o kernel-lib/tables.o kernel-lib/raid56.o transaction.o \ + delayed-ref.o cmds_objects = cmds-subvolume.o cmds-filesystem.o cmds-device.o cmds-scrub.o \ cmds-inspect.o cmds-balance.o cmds-send.o cmds-receive.o \ cmds-quota.o cmds-qgroup.o cmds-replace.o check/main.o \ @@ -2790,4 +2790,7 @@ int btrfs_punch_hole(struct btrfs_trans_handle *trans, int btrfs_read_file(struct btrfs_root *root, u64 ino, u64 start, int len, char *dest); +/* extent-tree.c */ +int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans, unsigned long nr); + #endif diff --git a/delayed-ref.c b/delayed-ref.c new file mode 100644 index 00000000..e8123436 --- /dev/null +++ b/delayed-ref.c @@ -0,0 +1,607 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2009 Oracle. All rights reserved. + */ + +#include "ctree.h" +#include "btrfs-list.h" +#include "delayed-ref.h" +#include "transaction.h" + +/* + * delayed back reference update tracking. For subvolume trees + * we queue up extent allocations and backref maintenance for + * delayed processing. This avoids deep call chains where we + * add extents in the middle of btrfs_search_slot, and it allows + * us to buffer up frequently modified backrefs in an rb tree instead + * of hammering updates on the extent allocation tree. + */ + +/* + * compare two delayed tree backrefs with same bytenr and type + */ +static int comp_tree_refs(struct btrfs_delayed_tree_ref *ref1, + struct btrfs_delayed_tree_ref *ref2) +{ + if (ref1->node.type == BTRFS_TREE_BLOCK_REF_KEY) { + if (ref1->root < ref2->root) + return -1; + if (ref1->root > ref2->root) + return 1; + } else { + if (ref1->parent < ref2->parent) + return -1; + if (ref1->parent > ref2->parent) + return 1; + } + return 0; +} + +static int comp_refs(struct btrfs_delayed_ref_node *ref1, + struct btrfs_delayed_ref_node *ref2, + bool check_seq) +{ + int ret = 0; + + if (ref1->type < ref2->type) + return -1; + if (ref1->type > ref2->type) + return 1; + if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY || + ref1->type == BTRFS_SHARED_BLOCK_REF_KEY) + ret = comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref1), + btrfs_delayed_node_to_tree_ref(ref2)); + else + BUG(); + + if (ret) + return ret; + if (check_seq) { + if (ref1->seq < ref2->seq) + return -1; + if (ref1->seq > ref2->seq) + return 1; + } + return 0; +} + +/* insert a new ref to head ref rbtree */ +static struct btrfs_delayed_ref_head *htree_insert(struct rb_root *root, + struct rb_node *node) +{ + struct rb_node **p = &root->rb_node; + struct rb_node *parent_node = NULL; + struct btrfs_delayed_ref_head *entry; + struct btrfs_delayed_ref_head *ins; + u64 bytenr; + + ins = rb_entry(node, struct btrfs_delayed_ref_head, href_node); + bytenr = ins->bytenr; + while (*p) { + parent_node = *p; + entry = rb_entry(parent_node, struct btrfs_delayed_ref_head, + href_node); + + if (bytenr < entry->bytenr) + p = &(*p)->rb_left; + else if (bytenr > entry->bytenr) + p = &(*p)->rb_right; + else + return entry; + } + + rb_link_node(node, parent_node, p); + rb_insert_color(node, root); + return NULL; +} + +static struct btrfs_delayed_ref_node* tree_insert(struct rb_root *root, + struct btrfs_delayed_ref_node *ins) +{ + struct rb_node **p = &root->rb_node; + struct rb_node *node = &ins->ref_node; + struct rb_node *parent_node = NULL; + struct btrfs_delayed_ref_node *entry; + + while (*p) { + int comp; + + parent_node = *p; + entry = rb_entry(parent_node, struct btrfs_delayed_ref_node, + ref_node); + comp = comp_refs(ins, entry, true); + if (comp < 0) + p = &(*p)->rb_left; + else if (comp > 0) + p = &(*p)->rb_right; + else + return entry; + } + + rb_link_node(node, parent_node, p); + rb_insert_color(node, root); + return NULL; +} + +/* + * find an head entry based on bytenr. This returns the delayed ref + * head if it was able to find one, or NULL if nothing was in that spot. + * If return_bigger is given, the next bigger entry is returned if no exact + * match is found. + */ +static struct btrfs_delayed_ref_head * +find_ref_head(struct rb_root *root, u64 bytenr, + int return_bigger) +{ + struct rb_node *n; + struct btrfs_delayed_ref_head *entry; + + n = root->rb_node; + entry = NULL; + while (n) { + entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node); + + if (bytenr < entry->bytenr) + n = n->rb_left; + else if (bytenr > entry->bytenr) + n = n->rb_right; + else + return entry; + } + if (entry && return_bigger) { + if (bytenr > entry->bytenr) { + n = rb_next(&entry->href_node); + if (!n) + n = rb_first(root); + entry = rb_entry(n, struct btrfs_delayed_ref_head, + href_node); + return entry; + } + return entry; + } + return NULL; +} + +static inline void drop_delayed_ref(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_root *delayed_refs, + struct btrfs_delayed_ref_head *head, + struct btrfs_delayed_ref_node *ref) +{ + rb_erase(&ref->ref_node, &head->ref_tree); + RB_CLEAR_NODE(&ref->ref_node); + if (!list_empty(&ref->add_list)) + list_del(&ref->add_list); + ref->in_tree = 0; + btrfs_put_delayed_ref(ref); + if (trans->delayed_ref_updates) + trans->delayed_ref_updates--; +} + +static bool merge_ref(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_root *delayed_refs, + struct btrfs_delayed_ref_head *head, + struct btrfs_delayed_ref_node *ref, + u64 seq) +{ + struct btrfs_delayed_ref_node *next; + struct rb_node *node = rb_next(&ref->ref_node); + bool done = false; + + while (!done && node) { + int mod; + + next = rb_entry(node, struct btrfs_delayed_ref_node, ref_node); + node = rb_next(node); + if (seq && next->seq >= seq) + break; + if (comp_refs(ref, next, false)) + break; + + if (ref->action == next->action) { + mod = next->ref_mod; + } else { + if (ref->ref_mod < next->ref_mod) { + swap(ref, next); + done = true; + } + mod = -next->ref_mod; + } + + drop_delayed_ref(trans, delayed_refs, head, next); + ref->ref_mod += mod; + if (ref->ref_mod == 0) { + drop_delayed_ref(trans, delayed_refs, head, ref); + done = true; + } else { + /* + * Can't have multiples of the same ref on a tree block. + */ + WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY || + ref->type == BTRFS_SHARED_BLOCK_REF_KEY); + } + } + + return done; +} + +void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_root *delayed_refs, + struct btrfs_delayed_ref_head *head) +{ + struct btrfs_delayed_ref_node *ref; + struct rb_node *node; + + if (RB_EMPTY_ROOT(&head->ref_tree)) + return; + + /* We don't have too many refs to merge for data. */ + if (head->is_data) + return; + +again: + for (node = rb_first(&head->ref_tree); node; node = rb_next(node)) { + ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node); + if (merge_ref(trans, delayed_refs, head, ref, 0)) + goto again; + } +} + +struct btrfs_delayed_ref_head * +btrfs_select_ref_head(struct btrfs_trans_handle *trans) +{ + struct btrfs_delayed_ref_root *delayed_refs; + struct btrfs_delayed_ref_head *head; + u64 start; + bool loop = false; + + delayed_refs = &trans->delayed_refs; + +again: + start = delayed_refs->run_delayed_start; + head = find_ref_head(&delayed_refs->href_root, start, 1); + if (!head && !loop) { + delayed_refs->run_delayed_start = 0; + start = 0; + loop = true; + head = find_ref_head(&delayed_refs->href_root, start, 1); + if (!head) + return NULL; + } else if (!head && loop) { + return NULL; + } + + while (head->processing) { + struct rb_node *node; + + node = rb_next(&head->href_node); + if (!node) { + if (loop) + return NULL; + delayed_refs->run_delayed_start = 0; + start = 0; + loop = true; + goto again; + } + head = rb_entry(node, struct btrfs_delayed_ref_head, + href_node); + } + + head->processing = 1; + WARN_ON(delayed_refs->num_heads_ready == 0); + delayed_refs->num_heads_ready--; + delayed_refs->run_delayed_start = head->bytenr + + head->num_bytes; + return head; +} + +/* + * Helper to insert the ref_node to the tail or merge with tail. + * + * Return 0 for insert. + * Return >0 for merge. + */ +static int insert_delayed_ref(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_root *root, + struct btrfs_delayed_ref_head *href, + struct btrfs_delayed_ref_node *ref) +{ + struct btrfs_delayed_ref_node *exist; + int mod; + int ret = 0; + + exist = tree_insert(&href->ref_tree, ref); + if (!exist) + goto inserted; + + /* Now we are sure we can merge */ + ret = 1; + if (exist->action == ref->action) { + mod = ref->ref_mod; + } else { + /* Need to change action */ + if (exist->ref_mod < ref->ref_mod) { + exist->action = ref->action; + mod = -exist->ref_mod; + exist->ref_mod = ref->ref_mod; + if (ref->action == BTRFS_ADD_DELAYED_REF) + list_add_tail(&exist->add_list, + &href->ref_add_list); + else if (ref->action == BTRFS_DROP_DELAYED_REF) { + ASSERT(!list_empty(&exist->add_list)); + list_del(&exist->add_list); + } else { + ASSERT(0); + } + } else + mod = -ref->ref_mod; + } + exist->ref_mod += mod; + + /* remove existing tail if its ref_mod is zero */ + if (exist->ref_mod == 0) + drop_delayed_ref(trans, root, href, exist); + return ret; +inserted: + if (ref->action == BTRFS_ADD_DELAYED_REF) + list_add_tail(&ref->add_list, &href->ref_add_list); + trans->delayed_ref_updates++; + return ret; +} + +/* + * helper function to update the accounting in the head ref + * existing and update must have the same bytenr + */ +static noinline void +update_existing_head_ref(struct btrfs_delayed_ref_root *delayed_refs, + struct btrfs_delayed_ref_head *existing, + struct btrfs_delayed_ref_head *update, + int *old_ref_mod_ret) +{ + int old_ref_mod; + + BUG_ON(existing->is_data != update->is_data); + + if (update->must_insert_reserved) { + /* if the extent was freed and then + * reallocated before the delayed ref + * entries were processed, we can end up + * with an existing head ref without + * the must_insert_reserved flag set. + * Set it again here + */ + existing->must_insert_reserved = update->must_insert_reserved; + + /* + * update the num_bytes so we make sure the accounting + * is done correctly + */ + existing->num_bytes = update->num_bytes; + + } + + if (update->extent_op) { + if (!existing->extent_op) { + existing->extent_op = update->extent_op; + } else { + if (update->extent_op->update_key) { + memcpy(&existing->extent_op->key, + &update->extent_op->key, + sizeof(update->extent_op->key)); + existing->extent_op->update_key = true; + } + if (update->extent_op->update_flags) { + existing->extent_op->flags_to_set |= + update->extent_op->flags_to_set; + existing->extent_op->update_flags = true; + } + btrfs_free_delayed_extent_op(update->extent_op); + } + } + /* + * update the reference mod on the head to reflect this new operation, + * only need the lock for this case cause we could be processing it + * currently, for refs we just added we know we're a-ok. + */ + old_ref_mod = existing->total_ref_mod; + if (old_ref_mod_ret) + *old_ref_mod_ret = old_ref_mod; + existing->ref_mod += update->ref_mod; + existing->total_ref_mod += update->ref_mod; + +} + +static void init_delayed_ref_head(struct btrfs_delayed_ref_head *head_ref, + void *qrecord, + u64 bytenr, u64 num_bytes, u64 ref_root, + u64 reserved, int action, bool is_data, + bool is_system) +{ + int count_mod = 1; + int must_insert_reserved = 0; + + /* If reserved is provided, it must be a data extent. */ + BUG_ON(!is_data && reserved); + + /* + * The head node stores the sum of all the mods, so dropping a ref + * should drop the sum in the head node by one. + */ + if (action == BTRFS_UPDATE_DELAYED_HEAD) + count_mod = 0; + else if (action == BTRFS_DROP_DELAYED_REF) + count_mod = -1; + + /* + * BTRFS_ADD_DELAYED_EXTENT means that we need to update the reserved + * accounting when the extent is finally added, or if a later + * modification deletes the delayed ref without ever inserting the + * extent into the extent allocation tree. ref->must_insert_reserved + * is the flag used to record that accounting mods are required. + * + * Once we record must_insert_reserved, switch the action to + * BTRFS_ADD_DELAYED_REF because other special casing is not required. + */ + if (action == BTRFS_ADD_DELAYED_EXTENT) + must_insert_reserved = 1; + else + must_insert_reserved = 0; + + head_ref->refs = 1; + head_ref->bytenr = bytenr; + head_ref->num_bytes = num_bytes; + head_ref->ref_mod = count_mod; + head_ref->must_insert_reserved = must_insert_reserved; + head_ref->is_data = is_data; + head_ref->is_system = is_system; + head_ref->ref_tree = RB_ROOT; + INIT_LIST_HEAD(&head_ref->ref_add_list); + RB_CLEAR_NODE(&head_ref->href_node); + head_ref->processing = 0; + head_ref->total_ref_mod = count_mod; +} + +/* + * helper function to actually insert a head node into the rbtree. + * this does all the dirty work in terms of maintaining the correct + * overall modification count. + */ +static noinline struct btrfs_delayed_ref_head * +add_delayed_ref_head(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_head *head_ref, + void *qrecord, + int action, int *qrecord_inserted_ret, + int *old_ref_mod, int *new_ref_mod) +{ + struct btrfs_delayed_ref_head *existing; + struct btrfs_delayed_ref_root *delayed_refs; + + delayed_refs = &trans->delayed_refs; + + existing = htree_insert(&delayed_refs->href_root, &head_ref->href_node); + if (existing) { + update_existing_head_ref(delayed_refs, existing, head_ref, old_ref_mod); + /* + * we've updated the existing ref, free the newly + * allocated ref + */ + kfree(head_ref); + head_ref = existing; + } else { + if (old_ref_mod) + *old_ref_mod = 0; + delayed_refs->num_heads++; + delayed_refs->num_heads_ready++; + trans->delayed_ref_updates++; + } + if (new_ref_mod) + *new_ref_mod = head_ref->total_ref_mod; + + return head_ref; +} + +/* + * init_delayed_ref_common - Initialize the structure which represents a + * modification to a an extent. + * + * @fs_info: Internal to the mounted filesystem mount structure. + * + * @ref: The structure which is going to be initialized. + * + * @bytenr: The logical address of the extent for which a modification is + * going to be recorded. + * + * @num_bytes: Size of the extent whose modification is being recorded. + * + * @ref_root: The id of the root where this modification has originated, this + * can be either one of the well-known metadata trees or the + * subvolume id which references this extent. + * + * @action: Can be one of BTRFS_ADD_DELAYED_REF/BTRFS_DROP_DELAYED_REF or + * BTRFS_ADD_DELAYED_EXTENT + * + * @ref_type: Holds the type of the extent which is being recorded, can be + * one of BTRFS_SHARED_BLOCK_REF_KEY/BTRFS_TREE_BLOCK_REF_KEY + * when recording a metadata extent or BTRFS_SHARED_DATA_REF_KEY/ + * BTRFS_EXTENT_DATA_REF_KEY when recording data extent + */ +static void init_delayed_ref_common(struct btrfs_fs_info *fs_info, + struct btrfs_delayed_ref_node *ref, + u64 bytenr, u64 num_bytes, u64 ref_root, + int action, u8 ref_type) +{ + if (action == BTRFS_ADD_DELAYED_EXTENT) + action = BTRFS_ADD_DELAYED_REF; + + ref->refs = 1; + ref->bytenr = bytenr; + ref->num_bytes = num_bytes; + ref->ref_mod = 1; + ref->action = action; + ref->is_head = 0; + ref->in_tree = 1; + ref->seq = 0; + ref->type = ref_type; + RB_CLEAR_NODE(&ref->ref_node); + INIT_LIST_HEAD(&ref->add_list); +} + +/* + * add a delayed tree ref. This does all of the accounting required + * to make sure the delayed ref is eventually processed before this + * transaction commits. + */ +int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info, + struct btrfs_trans_handle *trans, + u64 bytenr, u64 num_bytes, u64 parent, + u64 ref_root, int level, int action, + struct btrfs_delayed_extent_op *extent_op, + int *old_ref_mod, int *new_ref_mod) +{ + struct btrfs_delayed_tree_ref *ref; + struct btrfs_delayed_ref_head *head_ref; + struct btrfs_delayed_ref_root *delayed_refs; + bool is_system = (ref_root == BTRFS_CHUNK_TREE_OBJECTID); + int ret; + u8 ref_type; + + BUG_ON(extent_op && extent_op->is_data); + ref = kmalloc(sizeof(*ref), GFP_NOFS); + if (!ref) + return -ENOMEM; + + if (parent) + ref_type = BTRFS_SHARED_BLOCK_REF_KEY; + else + ref_type = BTRFS_TREE_BLOCK_REF_KEY; + init_delayed_ref_common(fs_info, &ref->node, bytenr, num_bytes, + ref_root, action, ref_type); + ref->root = ref_root; + ref->parent = parent; + ref->level = level; + + head_ref = kmalloc(sizeof(*head_ref), GFP_NOFS); + if (!head_ref) + goto free_ref; + + init_delayed_ref_head(head_ref, NULL, bytenr, num_bytes, + ref_root, 0, action, false, is_system); + head_ref->extent_op = extent_op; + + delayed_refs = &trans->delayed_refs; + + head_ref = add_delayed_ref_head(trans, head_ref, NULL, action, NULL, + old_ref_mod, new_ref_mod); + + ret = insert_delayed_ref(trans, delayed_refs, head_ref, &ref->node); + + if (ret > 0) + kfree(ref); + + return 0; + +free_ref: + kfree(ref); + + return -ENOMEM; +} diff --git a/delayed-ref.h b/delayed-ref.h new file mode 100644 index 00000000..30a68b2a --- /dev/null +++ b/delayed-ref.h @@ -0,0 +1,208 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2008 Oracle. All rights reserved. + */ + +#ifndef BTRFS_DELAYED_REF_H +#define BTRFS_DELAYED_REF_H + +#include "kerncompat.h" + +/* these are the possible values of struct btrfs_delayed_ref_node->action */ +#define BTRFS_ADD_DELAYED_REF 1 /* add one backref to the tree */ +#define BTRFS_DROP_DELAYED_REF 2 /* delete one backref from the tree */ +#define BTRFS_ADD_DELAYED_EXTENT 3 /* record a full extent allocation */ +#define BTRFS_UPDATE_DELAYED_HEAD 4 /* not changing ref count on head ref */ + +struct btrfs_delayed_ref_node { + struct rb_node ref_node; + /* + * If action is BTRFS_ADD_DELAYED_REF, also link this node to + * ref_head->ref_add_list, then we do not need to iterate the + * whole ref_head->ref_list to find BTRFS_ADD_DELAYED_REF nodes. + */ + struct list_head add_list; + + /* the starting bytenr of the extent */ + u64 bytenr; + + /* the size of the extent */ + u64 num_bytes; + + /* seq number to keep track of insertion order */ + u64 seq; + + /* ref count on this data structure */ + u64 refs; + + /* + * how many refs is this entry adding or deleting. For + * head refs, this may be a negative number because it is keeping + * track of the total mods done to the reference count. + * For individual refs, this will always be a positive number + * + * It may be more than one, since it is possible for a single + * parent to have more than one ref on an extent + */ + int ref_mod; + + unsigned int action:8; + unsigned int type:8; + /* is this node still in the rbtree? */ + unsigned int is_head:1; + unsigned int in_tree:1; +}; + +struct btrfs_delayed_extent_op { + struct btrfs_disk_key key; + u8 level; + bool update_key; + bool update_flags; + bool is_data; + u64 flags_to_set; +}; + +/* + * the head refs are used to hold a lock on a given extent, which allows us + * to make sure that only one process is running the delayed refs + * at a time for a single extent. They also store the sum of all the + * reference count modifications we've queued up. + */ +struct btrfs_delayed_ref_head { + u64 bytenr; + u64 num_bytes; + u64 refs; + + struct rb_root ref_tree; + /* accumulate add BTRFS_ADD_DELAYED_REF nodes to this ref_add_list. */ + struct list_head ref_add_list; + + struct rb_node href_node; + + struct btrfs_delayed_extent_op *extent_op; + + /* + * This is used to track the final ref_mod from all the refs associated + * with this head ref, this is not adjusted as delayed refs are run, + * this is meant to track if we need to do the csum accounting or not. + */ + int total_ref_mod; + + /* + * This is the current outstanding mod references for this bytenr. This + * is used with lookup_extent_info to get an accurate reference count + * for a bytenr, so it is adjusted as delayed refs are run so that any + * on disk reference count + ref_mod is accurate. + */ + int ref_mod; + + /* + * when a new extent is allocated, it is just reserved in memory + * The actual extent isn't inserted into the extent allocation tree + * until the delayed ref is processed. must_insert_reserved is + * used to flag a delayed ref so the accounting can be updated + * when a full insert is done. + * + * It is possible the extent will be freed before it is ever + * inserted into the extent allocation tree. In this case + * we need to update the in ram accounting to properly reflect + * the free has happened. + */ + unsigned int must_insert_reserved:1; + unsigned int is_data:1; + unsigned int is_system:1; + unsigned int processing:1; +}; + +struct btrfs_delayed_tree_ref { + struct btrfs_delayed_ref_node node; + u64 root; + u64 parent; + int level; +}; + +struct btrfs_delayed_ref_root { + /* head ref rbtree */ + struct rb_root href_root; + + /* dirty extent records */ + struct rb_root dirty_extent_root; + + /* total number of head nodes in tree */ + unsigned long num_heads; + + /* total number of head nodes ready for processing */ + unsigned long num_heads_ready; + + /* + * set when the tree is flushing before a transaction commit, + * used by the throttling code to decide if new updates need + * to be run right away + */ + int flushing; + + u64 run_delayed_start; +}; + + +static inline struct btrfs_delayed_extent_op * +btrfs_alloc_delayed_extent_op(void) +{ + return kmalloc(sizeof(struct btrfs_delayed_extent_op), GFP_KERNEL); +} + +static inline void +btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op) +{ + if (op) + kfree(op); +} + +static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref) +{ + WARN_ON(ref->refs == 0); + if (--ref->refs) { + WARN_ON(ref->in_tree); + switch (ref->type) { + case BTRFS_TREE_BLOCK_REF_KEY: + case BTRFS_SHARED_BLOCK_REF_KEY: + kfree(ref); + break; + case BTRFS_EXTENT_DATA_REF_KEY: + case BTRFS_SHARED_DATA_REF_KEY: + kfree(ref); + break; + default: + BUG(); + } + } +} + +static inline void btrfs_put_delayed_ref_head(struct btrfs_delayed_ref_head *head) +{ + if (--head->refs) + kfree(head); +} + +int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info, + struct btrfs_trans_handle *trans, + u64 bytenr, u64 num_bytes, u64 parent, + u64 ref_root, int level, int action, + struct btrfs_delayed_extent_op *extent_op, + int *old_ref_mod, int *new_ref_mod); +void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_root *delayed_refs, + struct btrfs_delayed_ref_head *head); + +struct btrfs_delayed_ref_head * +btrfs_select_ref_head(struct btrfs_trans_handle *trans); + +/* + * helper functions to cast a node into its container + */ +static inline struct btrfs_delayed_tree_ref * +btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node) +{ + return container_of(node, struct btrfs_delayed_tree_ref, node); +} +#endif diff --git a/extent-tree.c b/extent-tree.c index 3abb8a87..2958fee2 100644 --- a/extent-tree.c +++ b/extent-tree.c @@ -4219,3 +4219,229 @@ u64 add_new_free_space(struct btrfs_block_group_cache *block_group, return total_added; } + +static void cleanup_extent_op(struct btrfs_trans_handle *trans, + struct btrfs_fs_info *fs_info, + struct btrfs_delayed_ref_head *head) +{ + struct btrfs_delayed_extent_op *extent_op = head->extent_op; + + if (!extent_op) + return; + head->extent_op = NULL; + btrfs_free_delayed_extent_op(extent_op); +} + +static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs, + struct btrfs_delayed_ref_head *head) +{ + head->processing = 0; + delayed_refs->num_heads_ready++; +} + +static int cleanup_ref_head(struct btrfs_trans_handle *trans, + struct btrfs_fs_info *fs_info, + struct btrfs_delayed_ref_head *head) +{ + struct btrfs_delayed_ref_root *delayed_refs; + + delayed_refs = &trans->delayed_refs; + + cleanup_extent_op(trans, fs_info, head); + + /* + * Need to drop our head ref lock and re-acquire the delayed ref lock + * and then re-check to make sure nobody got added. + */ + if (!RB_EMPTY_ROOT(&head->ref_tree) || head->extent_op) + return 1; + + delayed_refs->num_heads--; + rb_erase(&head->href_node, &delayed_refs->href_root); + RB_CLEAR_NODE(&head->href_node); + + if (head->must_insert_reserved) + btrfs_pin_extent(fs_info, head->bytenr, head->num_bytes); + + btrfs_put_delayed_ref_head(head); + return 0; +} + +static inline struct btrfs_delayed_ref_node * +select_delayed_ref(struct btrfs_delayed_ref_head *head) +{ + struct btrfs_delayed_ref_node *ref; + + if (RB_EMPTY_ROOT(&head->ref_tree)) + return NULL; + /* + * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first. + * This is to prevent a ref count from going down to zero, which deletes + * the extent item from the extent tree, when there still are references + * to add, which would fail because they would not find the extent item. + */ + if (!list_empty(&head->ref_add_list)) + return list_first_entry(&head->ref_add_list, + struct btrfs_delayed_ref_node, + add_list); + ref = rb_entry(rb_first(&head->ref_tree), + struct btrfs_delayed_ref_node, ref_node); + ASSERT(list_empty(&ref->add_list)); + return ref; +} + + +static int run_delayed_tree_ref(struct btrfs_trans_handle *trans, + struct btrfs_fs_info *fs_info, + struct btrfs_delayed_ref_node *node, + struct btrfs_delayed_extent_op *extent_op, + int insert_reserved) +{ + int ret = 0; + struct btrfs_delayed_tree_ref *ref; + u64 parent = 0; + u64 ref_root = 0; + + ref = btrfs_delayed_node_to_tree_ref(node); + + if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) + parent = ref->parent; + ref_root = ref->root; + + if (node->ref_mod != 1) { + printf("btree block(%llu) has %d references rather than 1: action %d ref_root %llu parent %llu", + node->bytenr, node->ref_mod, node->action, ref_root, + parent); + return -EIO; + } + if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) { + BUG_ON(!extent_op || !extent_op->update_flags); + ret = alloc_reserved_tree_block2(trans, node, extent_op); + } else if (node->action == BTRFS_DROP_DELAYED_REF) { + ret = __free_extent2(trans, node, extent_op); + } else { + BUG(); + } + + return ret; +} + +/* helper function to actually process a single delayed ref entry */ +static int run_one_delayed_ref(struct btrfs_trans_handle *trans, + struct btrfs_fs_info *fs_info, + struct btrfs_delayed_ref_node *node, + struct btrfs_delayed_extent_op *extent_op, + int insert_reserved) +{ + int ret = 0; + + if (node->type == BTRFS_TREE_BLOCK_REF_KEY || + node->type == BTRFS_SHARED_BLOCK_REF_KEY) { + ret = run_delayed_tree_ref(trans, fs_info, node, extent_op, + insert_reserved); + } else + BUG(); + return ret; +} + +int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans, unsigned long nr) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_delayed_ref_root *delayed_refs; + struct btrfs_delayed_ref_node *ref; + struct btrfs_delayed_ref_head *locked_ref = NULL; + struct btrfs_delayed_extent_op *extent_op; + int ret; + int must_insert_reserved = 0; + + delayed_refs = &trans->delayed_refs; + while (1) { + if (!locked_ref) { + locked_ref = btrfs_select_ref_head(trans); + if (!locked_ref) + break; + } + /* + * We need to try and merge add/drops of the same ref since we + * can run into issues with relocate dropping the implicit ref + * and then it being added back again before the drop can + * finish. If we merged anything we need to re-loop so we can + * get a good ref. + * Or we can get node references of the same type that weren't + * merged when created due to bumps in the tree mod seq, and + * we need to merge them to prevent adding an inline extent + * backref before dropping it (triggering a BUG_ON at + * insert_inline_extent_backref()). + */ + btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref); + ref = select_delayed_ref(locked_ref); + /* + * We're done processing refs in this ref_head, clean everything + * up and move on to the next ref_head. + */ + if (!ref) { + ret = cleanup_ref_head(trans, fs_info, locked_ref); + if (ret > 0 ) { + /* We dropped our lock, we need to loop. */ + ret = 0; + continue; + } else if (ret) { + return ret; + } + locked_ref = NULL; + continue; + } + + ref->in_tree = 0; + rb_erase(&ref->ref_node, &locked_ref->ref_tree); + RB_CLEAR_NODE(&ref->ref_node); + if (!list_empty(&ref->add_list)) + list_del(&ref->add_list); + /* + * When we play the delayed ref, also correct the ref_mod on + * head + */ + switch (ref->action) { + case BTRFS_ADD_DELAYED_REF: + case BTRFS_ADD_DELAYED_EXTENT: + locked_ref->ref_mod -= ref->ref_mod; + break; + case BTRFS_DROP_DELAYED_REF: + locked_ref->ref_mod += ref->ref_mod; + break; + default: + WARN_ON(1); + } + + /* + * Record the must-insert_reserved flag before we drop the spin + * lock. + */ + must_insert_reserved = locked_ref->must_insert_reserved; + locked_ref->must_insert_reserved = 0; + + extent_op = locked_ref->extent_op; + locked_ref->extent_op = NULL; + + ret = run_one_delayed_ref(trans, fs_info, ref, extent_op, + must_insert_reserved); + + btrfs_free_delayed_extent_op(extent_op); + /* + * If we are re-initing extent tree in this transaction + * failure in freeing old roots are expected (because we don't + * have the old extent tree, hence backref resolution will + * return -EIO). + */ + if (ret && (!trans->reinit_extent_tree || + ref->action != BTRFS_DROP_DELAYED_REF)) { + unselect_delayed_ref_head(delayed_refs, locked_ref); + btrfs_put_delayed_ref(ref); + return ret; + } + + btrfs_put_delayed_ref(ref); + } + + return 0; +} diff --git a/kerncompat.h b/kerncompat.h index fa96715f..1a2bc18c 100644 --- a/kerncompat.h +++ b/kerncompat.h @@ -263,6 +263,14 @@ static inline int IS_ERR_OR_NULL(const void *ptr) return !ptr || IS_ERR(ptr); } +/** + * swap - swap values of @a and @b + * @a: first value + * @b: second value + */ +#define swap(a, b) \ + do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0) + /* * This looks more complex than it should be. But we need to * get the type for the ~ right in round_down (it needs to be diff --git a/transaction.h b/transaction.h index 750e329e..34060252 100644 --- a/transaction.h +++ b/transaction.h @@ -21,6 +21,7 @@ #include "kerncompat.h" #include "ctree.h" +#include "delayed-ref.h" struct btrfs_trans_handle { struct btrfs_fs_info *fs_info; @@ -28,9 +29,12 @@ struct btrfs_trans_handle { u64 alloc_exclude_start; u64 alloc_exclude_nr; bool reinit_extent_tree; + u64 delayed_ref_updates; unsigned long blocks_reserved; unsigned long blocks_used; struct btrfs_block_group_cache *block_group; + struct btrfs_delayed_ref_root delayed_refs; + }; struct btrfs_trans_handle* btrfs_start_transaction(struct btrfs_root *root, |