diff options
author | Chris Mason <chris.mason@oracle.com> | 2012-05-31 16:50:28 -0400 |
---|---|---|
committer | Chris Mason <chris.mason@oracle.com> | 2012-05-31 16:49:53 -0400 |
commit | 1e20932a23578bb1ec59107843574e259b96193f (patch) | |
tree | 844ae54293c4414fc4c232a36d0e4d4939dc35aa /fs/btrfs/ctree.c | |
parent | cfc442b69696b593cb442f09997dcb4cb5748171 (diff) | |
parent | c31931088fd6cf953bd0868a2647b6c3928e6c96 (diff) | |
download | linux-1e20932a23578bb1ec59107843574e259b96193f.tar.bz2 |
Merge branch 'for-chris' of git://git.jan-o-sch.net/btrfs-unstable into for-linus
Conflicts:
fs/btrfs/ulist.h
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/ctree.c')
-rw-r--r-- | fs/btrfs/ctree.c | 849 |
1 files changed, 823 insertions, 26 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 99fcad631a21..d7a96cfdc50a 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -18,6 +18,7 @@ #include <linux/sched.h> #include <linux/slab.h> +#include <linux/rbtree.h> #include "ctree.h" #include "disk-io.h" #include "transaction.h" @@ -37,7 +38,16 @@ static int balance_node_right(struct btrfs_trans_handle *trans, struct extent_buffer *dst_buf, struct extent_buffer *src_buf); static void del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root, - struct btrfs_path *path, int level, int slot); + struct btrfs_path *path, int level, int slot, + int tree_mod_log); +static void tree_mod_log_free_eb(struct btrfs_fs_info *fs_info, + struct extent_buffer *eb); +struct extent_buffer *read_old_tree_block(struct btrfs_root *root, u64 bytenr, + u32 blocksize, u64 parent_transid, + u64 time_seq); +struct extent_buffer *btrfs_find_old_tree_block(struct btrfs_root *root, + u64 bytenr, u32 blocksize, + u64 time_seq); struct btrfs_path *btrfs_alloc_path(void) { @@ -255,7 +265,7 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans, cow = btrfs_alloc_free_block(trans, root, buf->len, 0, new_root_objectid, &disk_key, level, - buf->start, 0, 1); + buf->start, 0); if (IS_ERR(cow)) return PTR_ERR(cow); @@ -288,6 +298,434 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans, return 0; } +enum mod_log_op { + MOD_LOG_KEY_REPLACE, + MOD_LOG_KEY_ADD, + MOD_LOG_KEY_REMOVE, + MOD_LOG_KEY_REMOVE_WHILE_FREEING, + MOD_LOG_KEY_REMOVE_WHILE_MOVING, + MOD_LOG_MOVE_KEYS, + MOD_LOG_ROOT_REPLACE, +}; + +struct tree_mod_move { + int dst_slot; + int nr_items; +}; + +struct tree_mod_root { + u64 logical; + u8 level; +}; + +struct tree_mod_elem { + struct rb_node node; + u64 index; /* shifted logical */ + struct seq_list elem; + enum mod_log_op op; + + /* this is used for MOD_LOG_KEY_* and MOD_LOG_MOVE_KEYS operations */ + int slot; + + /* this is used for MOD_LOG_KEY* and MOD_LOG_ROOT_REPLACE */ + u64 generation; + + /* those are used for op == MOD_LOG_KEY_{REPLACE,REMOVE} */ + struct btrfs_disk_key key; + u64 blockptr; + + /* this is used for op == MOD_LOG_MOVE_KEYS */ + struct tree_mod_move move; + + /* this is used for op == MOD_LOG_ROOT_REPLACE */ + struct tree_mod_root old_root; +}; + +static inline void +__get_tree_mod_seq(struct btrfs_fs_info *fs_info, struct seq_list *elem) +{ + elem->seq = atomic_inc_return(&fs_info->tree_mod_seq); + list_add_tail(&elem->list, &fs_info->tree_mod_seq_list); +} + +void btrfs_get_tree_mod_seq(struct btrfs_fs_info *fs_info, + struct seq_list *elem) +{ + elem->flags = 1; + spin_lock(&fs_info->tree_mod_seq_lock); + __get_tree_mod_seq(fs_info, elem); + spin_unlock(&fs_info->tree_mod_seq_lock); +} + +void btrfs_put_tree_mod_seq(struct btrfs_fs_info *fs_info, + struct seq_list *elem) +{ + struct rb_root *tm_root; + struct rb_node *node; + struct rb_node *next; + struct seq_list *cur_elem; + struct tree_mod_elem *tm; + u64 min_seq = (u64)-1; + u64 seq_putting = elem->seq; + + if (!seq_putting) + return; + + BUG_ON(!(elem->flags & 1)); + spin_lock(&fs_info->tree_mod_seq_lock); + list_del(&elem->list); + + list_for_each_entry(cur_elem, &fs_info->tree_mod_seq_list, list) { + if ((cur_elem->flags & 1) && cur_elem->seq < min_seq) { + if (seq_putting > cur_elem->seq) { + /* + * blocker with lower sequence number exists, we + * cannot remove anything from the log + */ + goto out; + } + min_seq = cur_elem->seq; + } + } + + /* + * anything that's lower than the lowest existing (read: blocked) + * sequence number can be removed from the tree. + */ + write_lock(&fs_info->tree_mod_log_lock); + tm_root = &fs_info->tree_mod_log; + for (node = rb_first(tm_root); node; node = next) { + next = rb_next(node); + tm = container_of(node, struct tree_mod_elem, node); + if (tm->elem.seq > min_seq) + continue; + rb_erase(node, tm_root); + list_del(&tm->elem.list); + kfree(tm); + } + write_unlock(&fs_info->tree_mod_log_lock); +out: + spin_unlock(&fs_info->tree_mod_seq_lock); +} + +/* + * key order of the log: + * index -> sequence + * + * the index is the shifted logical of the *new* root node for root replace + * operations, or the shifted logical of the affected block for all other + * operations. + */ +static noinline int +__tree_mod_log_insert(struct btrfs_fs_info *fs_info, struct tree_mod_elem *tm) +{ + struct rb_root *tm_root; + struct rb_node **new; + struct rb_node *parent = NULL; + struct tree_mod_elem *cur; + int ret = 0; + + BUG_ON(!tm || !tm->elem.seq); + + write_lock(&fs_info->tree_mod_log_lock); + tm_root = &fs_info->tree_mod_log; + new = &tm_root->rb_node; + while (*new) { + cur = container_of(*new, struct tree_mod_elem, node); + parent = *new; + if (cur->index < tm->index) + new = &((*new)->rb_left); + else if (cur->index > tm->index) + new = &((*new)->rb_right); + else if (cur->elem.seq < tm->elem.seq) + new = &((*new)->rb_left); + else if (cur->elem.seq > tm->elem.seq) + new = &((*new)->rb_right); + else { + kfree(tm); + ret = -EEXIST; + goto unlock; + } + } + + rb_link_node(&tm->node, parent, new); + rb_insert_color(&tm->node, tm_root); +unlock: + write_unlock(&fs_info->tree_mod_log_lock); + return ret; +} + +static inline int tree_mod_dont_log(struct btrfs_fs_info *fs_info, + struct extent_buffer *eb) { + smp_mb(); + if (list_empty(&(fs_info)->tree_mod_seq_list)) + return 1; + if (!eb) + return 0; + if (btrfs_header_level(eb) == 0) + return 1; + return 0; +} + +static inline int tree_mod_alloc(struct btrfs_fs_info *fs_info, gfp_t flags, + struct tree_mod_elem **tm_ret) +{ + struct tree_mod_elem *tm; + int seq; + + if (tree_mod_dont_log(fs_info, NULL)) + return 0; + + tm = *tm_ret = kzalloc(sizeof(*tm), flags); + if (!tm) + return -ENOMEM; + + tm->elem.flags = 0; + spin_lock(&fs_info->tree_mod_seq_lock); + if (list_empty(&fs_info->tree_mod_seq_list)) { + /* + * someone emptied the list while we were waiting for the lock. + * we must not add to the list, because no blocker exists. items + * are removed from the list only when the existing blocker is + * removed from the list. + */ + kfree(tm); + seq = 0; + } else { + __get_tree_mod_seq(fs_info, &tm->elem); + seq = tm->elem.seq; + } + spin_unlock(&fs_info->tree_mod_seq_lock); + + return seq; +} + +static noinline int +tree_mod_log_insert_key_mask(struct btrfs_fs_info *fs_info, + struct extent_buffer *eb, int slot, + enum mod_log_op op, gfp_t flags) +{ + struct tree_mod_elem *tm; + int ret; + + ret = tree_mod_alloc(fs_info, flags, &tm); + if (ret <= 0) + return ret; + + tm->index = eb->start >> PAGE_CACHE_SHIFT; + if (op != MOD_LOG_KEY_ADD) { + btrfs_node_key(eb, &tm->key, slot); + tm->blockptr = btrfs_node_blockptr(eb, slot); + } + tm->op = op; + tm->slot = slot; + tm->generation = btrfs_node_ptr_generation(eb, slot); + + return __tree_mod_log_insert(fs_info, tm); +} + +static noinline int +tree_mod_log_insert_key(struct btrfs_fs_info *fs_info, struct extent_buffer *eb, + int slot, enum mod_log_op op) +{ + return tree_mod_log_insert_key_mask(fs_info, eb, slot, op, GFP_NOFS); +} + +static noinline int +tree_mod_log_insert_move(struct btrfs_fs_info *fs_info, + struct extent_buffer *eb, int dst_slot, int src_slot, + int nr_items, gfp_t flags) +{ + struct tree_mod_elem *tm; + int ret; + int i; + + if (tree_mod_dont_log(fs_info, eb)) + return 0; + + for (i = 0; i + dst_slot < src_slot && i < nr_items; i++) { + ret = tree_mod_log_insert_key(fs_info, eb, i + dst_slot, + MOD_LOG_KEY_REMOVE_WHILE_MOVING); + BUG_ON(ret < 0); + } + + ret = tree_mod_alloc(fs_info, flags, &tm); + if (ret <= 0) + return ret; + + tm->index = eb->start >> PAGE_CACHE_SHIFT; + tm->slot = src_slot; + tm->move.dst_slot = dst_slot; + tm->move.nr_items = nr_items; + tm->op = MOD_LOG_MOVE_KEYS; + + return __tree_mod_log_insert(fs_info, tm); +} + +static noinline int +tree_mod_log_insert_root(struct btrfs_fs_info *fs_info, + struct extent_buffer *old_root, + struct extent_buffer *new_root, gfp_t flags) +{ + struct tree_mod_elem *tm; + int ret; + + ret = tree_mod_alloc(fs_info, flags, &tm); + if (ret <= 0) + return ret; + + tm->index = new_root->start >> PAGE_CACHE_SHIFT; + tm->old_root.logical = old_root->start; + tm->old_root.level = btrfs_header_level(old_root); + tm->generation = btrfs_header_generation(old_root); + tm->op = MOD_LOG_ROOT_REPLACE; + + return __tree_mod_log_insert(fs_info, tm); +} + +static struct tree_mod_elem * +__tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq, + int smallest) +{ + struct rb_root *tm_root; + struct rb_node *node; + struct tree_mod_elem *cur = NULL; + struct tree_mod_elem *found = NULL; + u64 index = start >> PAGE_CACHE_SHIFT; + + read_lock(&fs_info->tree_mod_log_lock); + tm_root = &fs_info->tree_mod_log; + node = tm_root->rb_node; + while (node) { + cur = container_of(node, struct tree_mod_elem, node); + if (cur->index < index) { + node = node->rb_left; + } else if (cur->index > index) { + node = node->rb_right; + } else if (cur->elem.seq < min_seq) { + node = node->rb_left; + } else if (!smallest) { + /* we want the node with the highest seq */ + if (found) + BUG_ON(found->elem.seq > cur->elem.seq); + found = cur; + node = node->rb_left; + } else if (cur->elem.seq > min_seq) { + /* we want the node with the smallest seq */ + if (found) + BUG_ON(found->elem.seq < cur->elem.seq); + found = cur; + node = node->rb_right; + } else { + found = cur; + break; + } + } + read_unlock(&fs_info->tree_mod_log_lock); + + return found; +} + +/* + * this returns the element from the log with the smallest time sequence + * value that's in the log (the oldest log item). any element with a time + * sequence lower than min_seq will be ignored. + */ +static struct tree_mod_elem * +tree_mod_log_search_oldest(struct btrfs_fs_info *fs_info, u64 start, + u64 min_seq) +{ + return __tree_mod_log_search(fs_info, start, min_seq, 1); +} + +/* + * this returns the element from the log with the largest time sequence + * value that's in the log (the most recent log item). any element with + * a time sequence lower than min_seq will be ignored. + */ +static struct tree_mod_elem * +tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq) +{ + return __tree_mod_log_search(fs_info, start, min_seq, 0); +} + +static inline void +tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct extent_buffer *dst, + struct extent_buffer *src, unsigned long dst_offset, + unsigned long src_offset, int nr_items) +{ + int ret; + int i; + + if (tree_mod_dont_log(fs_info, NULL)) + return; + + if (btrfs_header_level(dst) == 0 && btrfs_header_level(src) == 0) + return; + + /* speed this up by single seq for all operations? */ + for (i = 0; i < nr_items; i++) { + ret = tree_mod_log_insert_key(fs_info, src, i + src_offset, + MOD_LOG_KEY_REMOVE); + BUG_ON(ret < 0); + ret = tree_mod_log_insert_key(fs_info, dst, i + dst_offset, + MOD_LOG_KEY_ADD); + BUG_ON(ret < 0); + } +} + +static inline void +tree_mod_log_eb_move(struct btrfs_fs_info *fs_info, struct extent_buffer *dst, + int dst_offset, int src_offset, int nr_items) +{ + int ret; + ret = tree_mod_log_insert_move(fs_info, dst, dst_offset, src_offset, + nr_items, GFP_NOFS); + BUG_ON(ret < 0); +} + +static inline void +tree_mod_log_set_node_key(struct btrfs_fs_info *fs_info, + struct extent_buffer *eb, + struct btrfs_disk_key *disk_key, int slot, int atomic) +{ + int ret; + + ret = tree_mod_log_insert_key_mask(fs_info, eb, slot, + MOD_LOG_KEY_REPLACE, + atomic ? GFP_ATOMIC : GFP_NOFS); + BUG_ON(ret < 0); +} + +static void tree_mod_log_free_eb(struct btrfs_fs_info *fs_info, + struct extent_buffer *eb) +{ + int i; + int ret; + u32 nritems; + + if (tree_mod_dont_log(fs_info, eb)) + return; + + nritems = btrfs_header_nritems(eb); + for (i = nritems - 1; i >= 0; i--) { + ret = tree_mod_log_insert_key(fs_info, eb, i, + MOD_LOG_KEY_REMOVE_WHILE_FREEING); + BUG_ON(ret < 0); + } +} + +static inline void +tree_mod_log_set_root_pointer(struct btrfs_root *root, + struct extent_buffer *new_root_node) +{ + int ret; + tree_mod_log_free_eb(root->fs_info, root->node); + ret = tree_mod_log_insert_root(root->fs_info, root->node, + new_root_node, GFP_NOFS); + BUG_ON(ret < 0); +} + /* * check if the tree block can be shared by multiple trees */ @@ -409,6 +847,12 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans, ret = btrfs_dec_ref(trans, root, buf, 1, 1); BUG_ON(ret); /* -ENOMEM */ } + /* + * don't log freeing in case we're freeing the root node, this + * is done by tree_mod_log_set_root_pointer later + */ + if (buf != root->node && btrfs_header_level(buf) != 0) + tree_mod_log_free_eb(root->fs_info, buf); clean_tree_block(trans, root, buf); *last_ref = 1; } @@ -467,7 +911,7 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans, cow = btrfs_alloc_free_block(trans, root, buf->len, parent_start, root->root_key.objectid, &disk_key, - level, search_start, empty_size, 1); + level, search_start, empty_size); if (IS_ERR(cow)) return PTR_ERR(cow); @@ -506,10 +950,11 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans, parent_start = 0; extent_buffer_get(cow); + tree_mod_log_set_root_pointer(root, cow); rcu_assign_pointer(root->node, cow); btrfs_free_tree_block(trans, root, buf, parent_start, - last_ref, 1); + last_ref); free_extent_buffer(buf); add_root_to_dirty_list(root); } else { @@ -519,13 +964,15 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans, parent_start = 0; WARN_ON(trans->transid != btrfs_header_generation(parent)); + tree_mod_log_insert_key(root->fs_info, parent, parent_slot, + MOD_LOG_KEY_REPLACE); btrfs_set_node_blockptr(parent, parent_slot, cow->start); btrfs_set_node_ptr_generation(parent, parent_slot, trans->transid); btrfs_mark_buffer_dirty(parent); btrfs_free_tree_block(trans, root, buf, parent_start, - last_ref, 1); + last_ref); } if (unlock_orig) btrfs_tree_unlock(buf); @@ -535,6 +982,210 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans, return 0; } +/* + * returns the logical address of the oldest predecessor of the given root. + * entries older than time_seq are ignored. + */ +static struct tree_mod_elem * +__tree_mod_log_oldest_root(struct btrfs_fs_info *fs_info, + struct btrfs_root *root, u64 time_seq) +{ + struct tree_mod_elem *tm; + struct tree_mod_elem *found = NULL; + u64 root_logical = root->node->start; + int looped = 0; + + if (!time_seq) + return 0; + + /* + * the very last operation that's logged for a root is the replacement + * operation (if it is replaced at all). this has the index of the *new* + * root, making it the very first operation that's logged for this root. + */ + while (1) { + tm = tree_mod_log_search_oldest(fs_info, root_logical, + time_seq); + if (!looped && !tm) + return 0; + /* + * we must have key remove operations in the log before the + * replace operation. + */ + BUG_ON(!tm); + + if (tm->op != MOD_LOG_ROOT_REPLACE) + break; + + found = tm; + root_logical = tm->old_root.logical; + BUG_ON(root_logical == root->node->start); + looped = 1; + } + + return found; +} + +/* + * tm is a pointer to the first operation to rewind within eb. then, all + * previous operations will be rewinded (until we reach something older than + * time_seq). + */ +static void +__tree_mod_log_rewind(struct extent_buffer *eb, u64 time_seq, + struct tree_mod_elem *first_tm) +{ + u32 n; + struct rb_node *next; + struct tree_mod_elem *tm = first_tm; + unsigned long o_dst; + unsigned long o_src; + unsigned long p_size = sizeof(struct btrfs_key_ptr); + + n = btrfs_header_nritems(eb); + while (tm && tm->elem.seq >= time_seq) { + /* + * all the operations are recorded with the operator used for + * the modification. as we're going backwards, we do the + * opposite of each operation here. + */ + switch (tm->op) { + case MOD_LOG_KEY_REMOVE_WHILE_FREEING: + BUG_ON(tm->slot < n); + case MOD_LOG_KEY_REMOVE_WHILE_MOVING: + case MOD_LOG_KEY_REMOVE: + btrfs_set_node_key(eb, &tm->key, tm->slot); + btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr); + btrfs_set_node_ptr_generation(eb, tm->slot, + tm->generation); + n++; + break; + case MOD_LOG_KEY_REPLACE: + BUG_ON(tm->slot >= n); + btrfs_set_node_key(eb, &tm->key, tm->slot); + btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr); + btrfs_set_node_ptr_generation(eb, tm->slot, + tm->generation); + break; + case MOD_LOG_KEY_ADD: + if (tm->slot != n - 1) { + o_dst = btrfs_node_key_ptr_offset(tm->slot); + o_src = btrfs_node_key_ptr_offset(tm->slot + 1); + memmove_extent_buffer(eb, o_dst, o_src, p_size); + } + n--; + break; + case MOD_LOG_MOVE_KEYS: + o_dst = btrfs_node_key_ptr_offset(tm->slot); + o_src = btrfs_node_key_ptr_offset(tm->move.dst_slot); + memmove_extent_buffer(eb, o_dst, o_src, + tm->move.nr_items * p_size); + break; + case MOD_LOG_ROOT_REPLACE: + /* + * this operation is special. for roots, this must be + * handled explicitly before rewinding. + * for non-roots, this operation may exist if the node + * was a root: root A -> child B; then A gets empty and + * B is promoted to the new root. in the mod log, we'll + * have a root-replace operation for B, a tree block + * that is no root. we simply ignore that operation. + */ + break; + } + next = rb_next(&tm->node); + if (!next) + break; + tm = container_of(next, struct tree_mod_elem, node); + if (tm->index != first_tm->index) + break; + } + btrfs_set_header_nritems(eb, n); +} + +static struct extent_buffer * +tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct extent_buffer *eb, + u64 time_seq) +{ + struct extent_buffer *eb_rewin; + struct tree_mod_elem *tm; + + if (!time_seq) + return eb; + + if (btrfs_header_level(eb) == 0) + return eb; + + tm = tree_mod_log_search(fs_info, eb->start, time_seq); + if (!tm) + return eb; + + if (tm->op == MOD_LOG_KEY_REMOVE_WHILE_FREEING) { + BUG_ON(tm->slot != 0); + eb_rewin = alloc_dummy_extent_buffer(eb->start, + fs_info->tree_root->nodesize); + BUG_ON(!eb_rewin); + btrfs_set_header_bytenr(eb_rewin, eb->start); + btrfs_set_header_backref_rev(eb_rewin, + btrfs_header_backref_rev(eb)); + btrfs_set_header_owner(eb_rewin, btrfs_header_owner(eb)); + btrfs_set_header_level(eb_rewin, btrfs_header_level(eb)); + } else { + eb_rewin = btrfs_clone_extent_buffer(eb); + BUG_ON(!eb_rewin); + } + + extent_buffer_get(eb_rewin); + free_extent_buffer(eb); + + __tree_mod_log_rewind(eb_rewin, time_seq, tm); + + return eb_rewin; +} + +static inline struct extent_buffer * +get_old_root(struct btrfs_root *root, u64 time_seq) +{ + struct tree_mod_elem *tm; + struct extent_buffer *eb; + struct tree_mod_root *old_root; + u64 old_generation; + + tm = __tree_mod_log_oldest_root(root->fs_info, root, time_seq); + if (!tm) + return root->node; + + old_root = &tm->old_root; + old_generation = tm->generation; + + tm = tree_mod_log_search(root->fs_info, old_root->logical, time_seq); + /* + * there was an item in the log when __tree_mod_log_oldest_root + * returned. this one must not go away, because the time_seq passed to + * us must be blocking its removal. + */ + BUG_ON(!tm); + + if (old_root->logical == root->node->start) { + /* there are logged operations for the current root */ + eb = btrfs_clone_extent_buffer(root->node); + } else { + /* there's a root replace operation for the current root */ + eb = alloc_dummy_extent_buffer(tm->index << PAGE_CACHE_SHIFT, + root->nodesize); + btrfs_set_header_bytenr(eb, eb->start); + btrfs_set_header_backref_rev(eb, BTRFS_MIXED_BACKREF_REV); + btrfs_set_header_owner(eb, root->root_key.objectid); + } + if (!eb) + return NULL; + btrfs_set_header_level(eb, old_root->level); + btrfs_set_header_generation(eb, old_generation); + __tree_mod_log_rewind(eb, time_seq, tm); + + return eb; +} + static inline int should_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *buf) @@ -976,6 +1627,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, goto enospc; } + tree_mod_log_set_root_pointer(root, child); rcu_assign_pointer(root->node, child); add_root_to_dirty_list(root); @@ -989,7 +1641,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, free_extent_buffer(mid); root_sub_used(root, mid->len); - btrfs_free_tree_block(trans, root, mid, 0, 1, 0); + btrfs_free_tree_block(trans, root, mid, 0, 1); /* once for the root ptr */ free_extent_buffer_stale(mid); return 0; @@ -1042,14 +1694,16 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, if (btrfs_header_nritems(right) == 0) { clean_tree_block(trans, root, right); btrfs_tree_unlock(right); - del_ptr(trans, root, path, level + 1, pslot + 1); + del_ptr(trans, root, path, level + 1, pslot + 1, 1); root_sub_used(root, right->len); - btrfs_free_tree_block(trans, root, right, 0, 1, 0); + btrfs_free_tree_block(trans, root, right, 0, 1); free_extent_buffer_stale(right); right = NULL; } else { struct btrfs_disk_key right_key; btrfs_node_key(right, &right_key, 0); + tree_mod_log_set_node_key(root->fs_info, parent, + &right_key, pslot + 1, 0); btrfs_set_node_key(parent, &right_key, pslot + 1); btrfs_mark_buffer_dirty(parent); } @@ -1084,15 +1738,17 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, if (btrfs_header_nritems(mid) == 0) { clean_tree_block(trans, root, mid); btrfs_tree_unlock(mid); - del_ptr(trans, root, path, level + 1, pslot); + del_ptr(trans, root, path, level + 1, pslot, 1); root_sub_used(root, mid->len); - btrfs_free_tree_block(trans, root, mid, 0, 1, 0); + btrfs_free_tree_block(trans, root, mid, 0, 1); free_extent_buffer_stale(mid); mid = NULL; } else { /* update the parent key to reflect our changes */ struct btrfs_disk_key mid_key; btrfs_node_key(mid, &mid_key, 0); + tree_mod_log_set_node_key(root->fs_info, parent, &mid_key, + pslot, 0); btrfs_set_node_key(parent, &mid_key, pslot); btrfs_mark_buffer_dirty(parent); } @@ -1190,6 +1846,8 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, struct btrfs_disk_key disk_key; orig_slot += left_nr; btrfs_node_key(mid, &disk_key, 0); + tree_mod_log_set_node_key(root->fs_info, parent, + &disk_key, pslot, 0); btrfs_set_node_key(parent, &disk_key, pslot); btrfs_mark_buffer_dirty(parent); if (btrfs_header_nritems(left) > orig_slot) { @@ -1241,6 +1899,8 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, struct btrfs_disk_key disk_key; btrfs_node_key(right, &disk_key, 0); + tree_mod_log_set_node_key(root->fs_info, parent, + &disk_key, pslot + 1, 0); btrfs_set_node_key(parent, &disk_key, pslot + 1); btrfs_mark_buffer_dirty(parent); @@ -1498,7 +2158,7 @@ static int read_block_for_search(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *p, struct extent_buffer **eb_ret, int level, int slot, - struct btrfs_key *key) + struct btrfs_key *key, u64 time_seq) { u64 blocknr; u64 gen; @@ -1852,7 +2512,7 @@ cow_done: } err = read_block_for_search(trans, root, p, - &b, level, slot, key); + &b, level, slot, key, 0); if (err == -EAGAIN) goto again; if (err) { @@ -1924,6 +2584,115 @@ done: } /* + * Like btrfs_search_slot, this looks for a key in the given tree. It uses the + * current state of the tree together with the operations recorded in the tree + * modification log to search for the key in a previous version of this tree, as + * denoted by the time_seq parameter. + * + * Naturally, there is no support for insert, delete or cow operations. + * + * The resulting path and return value will be set up as if we called + * btrfs_search_slot at that point in time with ins_len and cow both set to 0. + */ +int btrfs_search_old_slot(struct btrfs_root *root, struct btrfs_key *key, + struct btrfs_path *p, u64 time_seq) +{ + struct extent_buffer *b; + int slot; + int ret; + int err; + int level; + int lowest_unlock = 1; + u8 lowest_level = 0; + + lowest_level = p->lowest_level; + WARN_ON(p->nodes[0] != NULL); + + if (p->search_commit_root) { + BUG_ON(time_seq); + return btrfs_search_slot(NULL, root, key, p, 0, 0); + } + +again: + b = get_old_root(root, time_seq); + extent_buffer_get(b); + level = btrfs_header_level(b); + btrfs_tree_read_lock(b); + p->locks[level] = BTRFS_READ_LOCK; + + while (b) { + level = btrfs_header_level(b); + p->nodes[level] = b; + btrfs_clear_path_blocking(p, NULL, 0); + + /* + * we have a lock on b and as long as we aren't changing + * the tree, there is no way to for the items in b to change. + * It is safe to drop the lock on our parent before we + * go through the expensive btree search on b. + */ + btrfs_unlock_up_safe(p, level + 1); + + ret = bin_search(b, key, level, &slot); + + if (level != 0) { + int dec = 0; + if (ret && slot > 0) { + dec = 1; + slot -= 1; + } + p->slots[level] = slot; + unlock_up(p, level, lowest_unlock, 0, NULL); + + if (level == lowest_level) { + if (dec) + p->slots[level]++; + goto done; + } + + err = read_block_for_search(NULL, root, p, &b, level, + slot, key, time_seq); + if (err == -EAGAIN) + goto again; + if (err) { + ret = err; + goto done; + } + + level = btrfs_header_level(b); + err = btrfs_try_tree_read_lock(b); + if (!err) { + btrfs_set_path_blocking(p); + btrfs_tree_read_lock(b); + btrfs_clear_path_blocking(p, b, + BTRFS_READ_LOCK); + } + p->locks[level] = BTRFS_READ_LOCK; + p->nodes[level] = b; + b = tree_mod_log_rewind(root->fs_info, b, time_seq); + if (b != p->nodes[level]) { + btrfs_tree_unlock_rw(p->nodes[level], + p->locks[level]); + p->locks[level] = 0; + p->nodes[level] = b; + } + } else { + p->slots[level] = slot; + unlock_up(p, level, lowest_unlock, 0, NULL); + goto done; + } + } + ret = 1; +done: + if (!p->leave_spinning) + btrfs_set_path_blocking(p); + if (ret < 0) + btrfs_release_path(p); + + return ret; +} + +/* * adjust the pointers going up the tree, starting at level * making sure the right key of each node is points to 'key'. * This is used after shifting pointers to the left, so it stops @@ -1943,6 +2712,7 @@ static void fixup_low_keys(struct btrfs_trans_handle *trans, if (!path->nodes[i]) break; t = path->nodes[i]; + tree_mod_log_set_node_key(root->fs_info, t, key, tslot, 1); btrfs_set_node_key(t, key, tslot); btrfs_mark_buffer_dirty(path->nodes[i]); if (tslot != 0) @@ -2025,12 +2795,16 @@ static int push_node_left(struct btrfs_trans_handle *trans, } else push_items = min(src_nritems - 8, push_items); + tree_mod_log_eb_copy(root->fs_info, dst, src, dst_nritems, 0, + push_items); copy_extent_buffer(dst, src, btrfs_node_key_ptr_offset(dst_nritems), btrfs_node_key_ptr_offset(0), push_items * sizeof(struct btrfs_key_ptr)); if (push_items < src_nritems) { + tree_mod_log_eb_move(root->fs_info, src, 0, push_items, + src_nritems - push_items); memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0), btrfs_node_key_ptr_offset(push_items), (src_nritems - push_items) * @@ -2084,11 +2858,14 @@ static int balance_node_right(struct btrfs_trans_handle *trans, if (max_push < push_items) push_items = max_push; + tree_mod_log_eb_move(root->fs_info, dst, push_items, 0, dst_nritems); memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items), btrfs_node_key_ptr_offset(0), (dst_nritems) * sizeof(struct btrfs_key_ptr)); + tree_mod_log_eb_copy(root->fs_info, dst, src, 0, + src_nritems - push_items, push_items); copy_extent_buffer(dst, src, btrfs_node_key_ptr_offset(0), btrfs_node_key_ptr_offset(src_nritems - push_items), @@ -2131,7 +2908,7 @@ static noinline int insert_new_root(struct btrfs_trans_handle *trans, c = btrfs_alloc_free_block(trans, root, root->nodesize, 0, root->root_key.objectid, &lower_key, - level, root->node->start, 0, 0); + level, root->node->start, 0); if (IS_ERR(c)) return PTR_ERR(c); @@ -2163,6 +2940,7 @@ static noinline int insert_new_root(struct btrfs_trans_handle *trans, btrfs_mark_buffer_dirty(c); old = root->node; + tree_mod_log_set_root_pointer(root, c); rcu_assign_pointer(root->node, c); /* the super has an extra ref to root->node */ @@ -2186,10 +2964,11 @@ static noinline int insert_new_root(struct btrfs_trans_handle *trans, static void insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, struct btrfs_disk_key *key, u64 bytenr, - int slot, int level) + int slot, int level, int tree_mod_log) { struct extent_buffer *lower; int nritems; + int ret; BUG_ON(!path->nodes[level]); btrfs_assert_tree_locked(path->nodes[level]); @@ -2198,11 +2977,19 @@ static void insert_ptr(struct btrfs_trans_handle *trans, BUG_ON(slot > nritems); BUG_ON(nritems == BTRFS_NODEPTRS_PER_BLOCK(root)); if (slot != nritems) { + if (tree_mod_log && level) + tree_mod_log_eb_move(root->fs_info, lower, slot + 1, + slot, nritems - slot); memmove_extent_buffer(lower, btrfs_node_key_ptr_offset(slot + 1), btrfs_node_key_ptr_offset(slot), (nritems - slot) * sizeof(struct btrfs_key_ptr)); } + if (tree_mod_log && level) { + ret = tree_mod_log_insert_key(root->fs_info, lower, slot, + MOD_LOG_KEY_ADD); + BUG_ON(ret < 0); + } btrfs_set_node_key(lower, key, slot); btrfs_set_node_blockptr(lower, slot, bytenr); WARN_ON(trans->transid == 0); @@ -2254,7 +3041,7 @@ static noinline int split_node(struct btrfs_trans_handle *trans, split = btrfs_alloc_free_block(trans, root, root->nodesize, 0, root->root_key.objectid, - &disk_key, level, c->start, 0, 0); + &disk_key, level, c->start, 0); if (IS_ERR(split)) return PTR_ERR(split); @@ -2273,7 +3060,7 @@ static noinline int split_node(struct btrfs_trans_handle *trans, (unsigned long)btrfs_header_chunk_tree_uuid(split), BTRFS_UUID_SIZE); - + tree_mod_log_eb_copy(root->fs_info, split, c, 0, mid, c_nritems - mid); copy_extent_buffer(split, c, btrfs_node_key_ptr_offset(0), btrfs_node_key_ptr_offset(mid), @@ -2286,7 +3073,7 @@ static noinline int split_node(struct btrfs_trans_handle *trans, btrfs_mark_buffer_dirty(split); insert_ptr(trans, root, path, &disk_key, split->start, - path->slots[level + 1] + 1, level + 1); + path->slots[level + 1] + 1, level + 1, 1); if (path->slots[level] >= mid) { path->slots[level] -= mid; @@ -2823,7 +3610,7 @@ static noinline void copy_for_split(struct btrfs_trans_handle *trans, btrfs_set_header_nritems(l, mid); btrfs_item_key(right, &disk_key, 0); insert_ptr(trans, root, path, &disk_key, right->start, - path->slots[1] + 1, 1); + path->slots[1] + 1, 1, 0); btrfs_mark_buffer_dirty(right); btrfs_mark_buffer_dirty(l); @@ -3006,7 +3793,7 @@ again: right = btrfs_alloc_free_block(trans, root, root->leafsize, 0, root->root_key.objectid, - &disk_key, 0, l->start, 0, 0); + &disk_key, 0, l->start, 0); if (IS_ERR(right)) return PTR_ERR(right); @@ -3030,7 +3817,7 @@ again: if (mid <= slot) { btrfs_set_header_nritems(right, 0); insert_ptr(trans, root, path, &disk_key, right->start, - path->slots[1] + 1, 1); + path->slots[1] + 1, 1, 0); btrfs_tree_unlock(path->nodes[0]); free_extent_buffer(path->nodes[0]); path->nodes[0] = right; @@ -3039,7 +3826,7 @@ again: } else { btrfs_set_header_nritems(right, 0); insert_ptr(trans, root, path, &disk_key, right->start, - path->slots[1], 1); + path->slots[1], 1, 0); btrfs_tree_unlock(path->nodes[0]); free_extent_buffer(path->nodes[0]); path->nodes[0] = right; @@ -3751,19 +4538,29 @@ int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root * empty a node. */ static void del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root, - struct btrfs_path *path, int level, int slot) + struct btrfs_path *path, int level, int slot, + int tree_mod_log) { struct extent_buffer *parent = path->nodes[level]; u32 nritems; + int ret; nritems = btrfs_header_nritems(parent); if (slot != nritems - 1) { + if (tree_mod_log && level) + tree_mod_log_eb_move(root->fs_info, parent, slot, + slot + 1, nritems - slot - 1); memmove_extent_buffer(parent, btrfs_node_key_ptr_offset(slot), btrfs_node_key_ptr_offset(slot + 1), sizeof(struct btrfs_key_ptr) * (nritems - slot - 1)); + } else if (tree_mod_log && level) { + ret = tree_mod_log_insert_key(root->fs_info, parent, slot, + MOD_LOG_KEY_REMOVE); + BUG_ON(ret < 0); } + nritems--; btrfs_set_header_nritems(parent, nritems); if (nritems == 0 && parent == root->node) { @@ -3795,7 +4592,7 @@ static noinline void btrfs_del_leaf(struct btrfs_trans_handle *trans, struct extent_buffer *leaf) { WARN_ON(btrfs_header_generation(leaf) != trans->transid); - del_ptr(trans, root, path, 1, path->slots[1]); + del_ptr(trans, root, path, 1, path->slots[1], 1); /* * btrfs_free_extent is expensive, we want to make sure we @@ -3806,7 +4603,7 @@ static noinline void btrfs_del_leaf(struct btrfs_trans_handle *trans, root_sub_used(root, leaf->len); extent_buffer_get(leaf); - btrfs_free_tree_block(trans, root, leaf, 0, 1, 0); + btrfs_free_tree_block(trans, root, leaf, 0, 1); free_extent_buffer_stale(leaf); } /* @@ -4273,7 +5070,7 @@ again: next = c; next_rw_lock = path->locks[level]; ret = read_block_for_search(NULL, root, path, &next, level, - slot, &key); + slot, &key, 0); if (ret == -EAGAIN) goto again; @@ -4310,7 +5107,7 @@ again: break; ret = read_block_for_search(NULL, root, path, &next, level, - 0, &key); + 0, &key, 0); if (ret == -EAGAIN) goto again; |