#include <linux/sched.h>
#include <linux/slab.h>
+#include <linux/rbtree.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
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)
{
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);
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;
+}
+
+/*
+ * This allocates memory and gets a tree modification sequence number when
+ * needed.
+ *
+ * Returns 0 when no sequence number is needed, < 0 on error.
+ * Returns 1 when a sequence number was added. In this case,
+ * fs_info->tree_mod_seq_lock was acquired and must be released by the caller
+ * after inserting into the rb tree.
+ */
+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;
+ spin_unlock(&fs_info->tree_mod_seq_lock);
+ } else {
+ __get_tree_mod_seq(fs_info, &tm->elem);
+ seq = tm->elem.seq;
+ }
+
+ 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);
+
+ ret = __tree_mod_log_insert(fs_info, tm);
+ spin_unlock(&fs_info->tree_mod_seq_lock);
+ return ret;
+}
+
+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;
+
+ ret = __tree_mod_log_insert(fs_info, tm);
+ spin_unlock(&fs_info->tree_mod_seq_lock);
+ return ret;
+}
+
+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;
+
+ ret = __tree_mod_log_insert(fs_info, tm);
+ spin_unlock(&fs_info->tree_mod_seq_lock);
+ return ret;
+}
+
+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
*/
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;
}
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);
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 {
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);
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;
+ }
+
+ /* if there's no old root to return, return what we found instead */
+ if (!found)
+ found = tm;
+
+ 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;
+}
+
+/*
+ * get_old_root() rewinds the state of @root's root node to the given @time_seq
+ * value. If there are no changes, the current root->root_node is returned. If
+ * anything changed in between, there's a fresh buffer allocated on which the
+ * rewind operations are done. In any case, the returned buffer is read locked.
+ * Returns NULL on error (with no locks held).
+ */
+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 = NULL;
+ u64 old_generation = 0;
+ u64 logical;
+
+ eb = btrfs_read_lock_root_node(root);
+ tm = __tree_mod_log_oldest_root(root->fs_info, root, time_seq);
+ if (!tm)
+ return root->node;
+
+ if (tm->op == MOD_LOG_ROOT_REPLACE) {
+ old_root = &tm->old_root;
+ old_generation = tm->generation;
+ logical = old_root->logical;
+ } else {
+ logical = root->node->start;
+ }
+
+ tm = tree_mod_log_search(root->fs_info, 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)
+ eb = alloc_dummy_extent_buffer(tm->index << PAGE_CACHE_SHIFT,
+ root->nodesize);
+ else
+ eb = btrfs_clone_extent_buffer(root->node);
+ btrfs_tree_read_unlock(root->node);
+ free_extent_buffer(root->node);
+ if (!eb)
+ return NULL;
+ btrfs_tree_read_lock(eb);
+ if (old_root) {
+ 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);
+ btrfs_set_header_level(eb, old_root->level);
+ btrfs_set_header_generation(eb, old_generation);
+ }
+ __tree_mod_log_rewind(eb, time_seq, tm);
+ extent_buffer_get(eb);
+
+ return eb;
+}
+
static inline int should_cow_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf)
if (!cur)
return -EIO;
} else if (!uptodate) {
- btrfs_read_buffer(cur, gen);
+ err = btrfs_read_buffer(cur, gen);
+ if (err) {
+ free_extent_buffer(cur);
+ return err;
+ }
}
}
if (search_start == 0)
static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
int level, int *slot)
{
- if (level == 0) {
+ if (level == 0)
return generic_bin_search(eb,
offsetof(struct btrfs_leaf, items),
sizeof(struct btrfs_item),
key, btrfs_header_nritems(eb),
slot);
- } else {
+ else
return generic_bin_search(eb,
offsetof(struct btrfs_node, ptrs),
sizeof(struct btrfs_key_ptr),
key, btrfs_header_nritems(eb),
slot);
- }
- return -1;
}
int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key,
goto enospc;
}
+ tree_mod_log_set_root_pointer(root, child);
rcu_assign_pointer(root->node, child);
add_root_to_dirty_list(root);
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;
BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
return 0;
- btrfs_header_nritems(mid);
-
left = read_node_slot(root, parent, pslot - 1);
if (left) {
btrfs_tree_lock(left);
wret = push_node_left(trans, root, left, mid, 1);
if (wret < 0)
ret = wret;
- btrfs_header_nritems(mid);
}
/*
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);
}
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);
}
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) {
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);
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;
}
err = read_block_for_search(trans, root, p,
- &b, level, slot, key);
+ &b, level, slot, key, 0);
if (err == -EAGAIN)
goto again;
if (err) {
return ret;
}
+/*
+ * 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);
+ level = btrfs_header_level(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'.
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)
} 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) *
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),
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);
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 */
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]);
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);
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);
(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),
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;
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);
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);
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;
} 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;
* 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) {
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
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);
}
/*
* returns < 0 on io errors.
*/
int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
+{
+ return btrfs_next_old_leaf(root, path, 0);
+}
+
+int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
+ u64 time_seq)
{
int slot;
int level;
path->keep_locks = 1;
path->leave_spinning = 1;
- ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (time_seq)
+ ret = btrfs_search_old_slot(root, &key, path, time_seq);
+ else
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
path->keep_locks = 0;
if (ret < 0)
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;
break;
ret = read_block_for_search(NULL, root, path, &next, level,
- 0, &key);
+ 0, &key, 0);
if (ret == -EAGAIN)
goto again;
projects / karo-tx-linux.git / blobdiff