Commit 31840ae1 authored by Zheng Yan's avatar Zheng Yan Committed by Chris Mason
Browse files

Btrfs: Full back reference support



This patch makes the back reference system to explicit record the
location of parent node for all types of extents. The location of
parent node is placed into the offset field of backref key. Every
time a tree block is balanced, the back references for the affected
lower level extents are updated.
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 1c2308f8
......@@ -125,7 +125,6 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
u32 nritems;
int ret = 0;
int level;
struct btrfs_key first_key;
struct btrfs_root *new_root;
new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
......@@ -141,18 +140,10 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
level = btrfs_header_level(buf);
nritems = btrfs_header_nritems(buf);
if (nritems) {
if (level == 0)
btrfs_item_key_to_cpu(buf, &first_key, 0);
else
btrfs_node_key_to_cpu(buf, &first_key, 0);
} else {
first_key.objectid = 0;
}
cow = btrfs_alloc_free_block(trans, new_root, buf->len,
new_root_objectid,
trans->transid, first_key.objectid,
level, buf->start, 0);
cow = btrfs_alloc_free_block(trans, new_root, buf->len, 0,
new_root_objectid, trans->transid,
level, buf->start, 0);
if (IS_ERR(cow)) {
kfree(new_root);
return PTR_ERR(cow);
......@@ -165,7 +156,7 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
WARN_ON(btrfs_header_generation(buf) > trans->transid);
ret = btrfs_inc_ref(trans, new_root, buf, 0);
ret = btrfs_inc_ref(trans, new_root, buf, cow, NULL);
kfree(new_root);
if (ret)
......@@ -184,39 +175,31 @@ int noinline __btrfs_cow_block(struct btrfs_trans_handle *trans,
u64 search_start, u64 empty_size,
u64 prealloc_dest)
{
u64 root_gen;
u64 parent_start;
struct extent_buffer *cow;
u32 nritems;
int ret = 0;
int different_trans = 0;
int level;
int unlock_orig = 0;
struct btrfs_key first_key;
if (*cow_ret == buf)
unlock_orig = 1;
WARN_ON(!btrfs_tree_locked(buf));
if (root->ref_cows) {
root_gen = trans->transid;
} else {
root_gen = 0;
}
if (parent)
parent_start = parent->start;
else
parent_start = 0;
WARN_ON(root->ref_cows && trans->transid !=
root->fs_info->running_transaction->transid);
WARN_ON(root->ref_cows && trans->transid != root->last_trans);
level = btrfs_header_level(buf);
nritems = btrfs_header_nritems(buf);
if (nritems) {
if (level == 0)
btrfs_item_key_to_cpu(buf, &first_key, 0);
else
btrfs_node_key_to_cpu(buf, &first_key, 0);
} else {
first_key.objectid = 0;
}
if (prealloc_dest) {
struct btrfs_key ins;
......@@ -224,19 +207,19 @@ int noinline __btrfs_cow_block(struct btrfs_trans_handle *trans,
ins.offset = buf->len;
ins.type = BTRFS_EXTENT_ITEM_KEY;
ret = btrfs_alloc_reserved_extent(trans, root,
ret = btrfs_alloc_reserved_extent(trans, root, parent_start,
root->root_key.objectid,
root_gen, level,
first_key.objectid,
trans->transid, level, 0,
&ins);
BUG_ON(ret);
cow = btrfs_init_new_buffer(trans, root, prealloc_dest,
buf->len);
} else {
cow = btrfs_alloc_free_block(trans, root, buf->len,
parent_start,
root->root_key.objectid,
root_gen, first_key.objectid,
level, search_start, empty_size);
trans->transid, level,
search_start, empty_size);
}
if (IS_ERR(cow))
return PTR_ERR(cow);
......@@ -249,17 +232,23 @@ int noinline __btrfs_cow_block(struct btrfs_trans_handle *trans,
WARN_ON(btrfs_header_generation(buf) > trans->transid);
if (btrfs_header_generation(buf) != trans->transid) {
u32 nr_extents;
different_trans = 1;
ret = btrfs_inc_ref(trans, root, buf, 1);
ret = btrfs_inc_ref(trans, root, buf, cow, &nr_extents);
if (ret)
return ret;
ret = btrfs_cache_ref(trans, root, buf, nr_extents);
WARN_ON(ret);
} else {
ret = btrfs_update_ref(trans, root, buf, cow, 0, nritems);
if (ret)
return ret;
clean_tree_block(trans, root, buf);
}
if (buf == root->node) {
WARN_ON(parent && parent != buf);
root_gen = btrfs_header_generation(buf);
spin_lock(&root->node_lock);
root->node = cow;
......@@ -268,13 +257,14 @@ int noinline __btrfs_cow_block(struct btrfs_trans_handle *trans,
if (buf != root->commit_root) {
btrfs_free_extent(trans, root, buf->start,
buf->len, root->root_key.objectid,
root_gen, 0, 0, 1);
buf->len, buf->start,
root->root_key.objectid,
btrfs_header_generation(buf),
0, 0, 1);
}
free_extent_buffer(buf);
add_root_to_dirty_list(root);
} else {
root_gen = btrfs_header_generation(parent);
btrfs_set_node_blockptr(parent, parent_slot,
cow->start);
WARN_ON(trans->transid == 0);
......@@ -283,8 +273,8 @@ int noinline __btrfs_cow_block(struct btrfs_trans_handle *trans,
btrfs_mark_buffer_dirty(parent);
WARN_ON(btrfs_header_generation(parent) != trans->transid);
btrfs_free_extent(trans, root, buf->start, buf->len,
btrfs_header_owner(parent), root_gen,
0, 0, 1);
parent_start, btrfs_header_owner(parent),
btrfs_header_generation(parent), 0, 0, 1);
}
if (unlock_orig)
btrfs_tree_unlock(buf);
......@@ -831,6 +821,12 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
root->node = child;
spin_unlock(&root->node_lock);
ret = btrfs_update_extent_ref(trans, root, child->start,
mid->start, child->start,
root->root_key.objectid,
trans->transid, level - 1, 0);
BUG_ON(ret);
add_root_to_dirty_list(root);
btrfs_tree_unlock(child);
path->locks[level] = 0;
......@@ -840,7 +836,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
/* once for the path */
free_extent_buffer(mid);
ret = btrfs_free_extent(trans, root, mid->start, mid->len,
root->root_key.objectid,
mid->start, root->root_key.objectid,
btrfs_header_generation(mid), 0, 0, 1);
/* once for the root ptr */
free_extent_buffer(mid);
......@@ -905,7 +901,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
if (wret)
ret = wret;
wret = btrfs_free_extent(trans, root, bytenr,
blocksize,
blocksize, parent->start,
btrfs_header_owner(parent),
generation, 0, 0, 1);
if (wret)
......@@ -954,6 +950,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
if (wret)
ret = wret;
wret = btrfs_free_extent(trans, root, bytenr, blocksize,
parent->start,
btrfs_header_owner(parent),
root_gen, 0, 0, 1);
if (wret)
......@@ -1499,6 +1496,41 @@ static int fixup_low_keys(struct btrfs_trans_handle *trans,
return ret;
}
/*
* update item key.
*
* This function isn't completely safe. It's the caller's responsibility
* that the new key won't break the order
*/
int btrfs_set_item_key_safe(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct btrfs_path *path,
struct btrfs_key *new_key)
{
struct btrfs_disk_key disk_key;
struct extent_buffer *eb;
int slot;
eb = path->nodes[0];
slot = path->slots[0];
if (slot > 0) {
btrfs_item_key(eb, &disk_key, slot - 1);
if (comp_keys(&disk_key, new_key) >= 0)
return -1;
}
if (slot < btrfs_header_nritems(eb) - 1) {
btrfs_item_key(eb, &disk_key, slot + 1);
if (comp_keys(&disk_key, new_key) <= 0)
return -1;
}
btrfs_cpu_key_to_disk(&disk_key, new_key);
btrfs_set_item_key(eb, &disk_key, slot);
btrfs_mark_buffer_dirty(eb);
if (slot == 0)
fixup_low_keys(trans, root, path, &disk_key, 1);
return 0;
}
/*
* try to push data from one node into the next node left in the
* tree.
......@@ -1558,6 +1590,10 @@ static int push_node_left(struct btrfs_trans_handle *trans,
btrfs_set_header_nritems(dst, dst_nritems + push_items);
btrfs_mark_buffer_dirty(src);
btrfs_mark_buffer_dirty(dst);
ret = btrfs_update_ref(trans, root, src, dst, dst_nritems, push_items);
BUG_ON(ret);
return ret;
}
......@@ -1619,6 +1655,10 @@ static int balance_node_right(struct btrfs_trans_handle *trans,
btrfs_mark_buffer_dirty(src);
btrfs_mark_buffer_dirty(dst);
ret = btrfs_update_ref(trans, root, src, dst, 0, push_items);
BUG_ON(ret);
return ret;
}
......@@ -1633,30 +1673,24 @@ static int noinline insert_new_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, int level)
{
u64 root_gen;
u64 lower_gen;
struct extent_buffer *lower;
struct extent_buffer *c;
struct extent_buffer *old;
struct btrfs_disk_key lower_key;
int ret;
BUG_ON(path->nodes[level]);
BUG_ON(path->nodes[level-1] != root->node);
if (root->ref_cows)
root_gen = trans->transid;
else
root_gen = 0;
lower = path->nodes[level-1];
if (level == 1)
btrfs_item_key(lower, &lower_key, 0);
else
btrfs_node_key(lower, &lower_key, 0);
c = btrfs_alloc_free_block(trans, root, root->nodesize,
root->root_key.objectid,
root_gen, le64_to_cpu(lower_key.objectid),
c = btrfs_alloc_free_block(trans, root, root->nodesize, 0,
root->root_key.objectid, trans->transid,
level, root->node->start, 0);
if (IS_ERR(c))
return PTR_ERR(c);
......@@ -1679,7 +1713,7 @@ static int noinline insert_new_root(struct btrfs_trans_handle *trans,
btrfs_set_node_key(c, &lower_key, 0);
btrfs_set_node_blockptr(c, 0, lower->start);
lower_gen = btrfs_header_generation(lower);
WARN_ON(lower_gen == 0);
WARN_ON(lower_gen != trans->transid);
btrfs_set_node_ptr_generation(c, 0, lower_gen);
......@@ -1690,6 +1724,12 @@ static int noinline insert_new_root(struct btrfs_trans_handle *trans,
root->node = c;
spin_unlock(&root->node_lock);
ret = btrfs_update_extent_ref(trans, root, lower->start,
lower->start, c->start,
root->root_key.objectid,
trans->transid, level - 1, 0);
BUG_ON(ret);
/* the super has an extra ref to root->node */
free_extent_buffer(old);
......@@ -1698,20 +1738,6 @@ static int noinline insert_new_root(struct btrfs_trans_handle *trans,
path->nodes[level] = c;
path->locks[level] = 1;
path->slots[level] = 0;
if (root->ref_cows && lower_gen != trans->transid) {
struct btrfs_path *back_path = btrfs_alloc_path();
int ret;
mutex_lock(&root->fs_info->alloc_mutex);
ret = btrfs_insert_extent_backref(trans,
root->fs_info->extent_root,
path, lower->start,
root->root_key.objectid,
trans->transid, 0, 0);
BUG_ON(ret);
mutex_unlock(&root->fs_info->alloc_mutex);
btrfs_free_path(back_path);
}
return 0;
}
......@@ -1766,7 +1792,6 @@ static noinline int split_node(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, int level)
{
u64 root_gen;
struct extent_buffer *c;
struct extent_buffer *split;
struct btrfs_disk_key disk_key;
......@@ -1793,17 +1818,11 @@ static noinline int split_node(struct btrfs_trans_handle *trans,
}
c_nritems = btrfs_header_nritems(c);
if (root->ref_cows)
root_gen = trans->transid;
else
root_gen = 0;
btrfs_node_key(c, &disk_key, 0);
split = btrfs_alloc_free_block(trans, root, root->nodesize,
root->root_key.objectid,
root_gen,
btrfs_disk_key_objectid(&disk_key),
level, c->start, 0);
path->nodes[level + 1]->start,
root->root_key.objectid,
trans->transid, level, c->start, 0);
if (IS_ERR(split))
return PTR_ERR(split);
......@@ -1840,6 +1859,9 @@ static noinline int split_node(struct btrfs_trans_handle *trans,
if (wret)
ret = wret;
ret = btrfs_update_ref(trans, root, c, split, 0, c_nritems - mid);
BUG_ON(ret);
if (path->slots[level] >= mid) {
path->slots[level] -= mid;
btrfs_tree_unlock(c);
......@@ -1955,10 +1977,23 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
else
nr = 1;
if (path->slots[0] >= left_nritems)
push_space += data_size + sizeof(*item);
i = left_nritems - 1;
while (i >= nr) {
item = btrfs_item_nr(left, i);
if (!empty && push_items > 0) {
if (path->slots[0] > i)
break;
if (path->slots[0] == i) {
int space = btrfs_leaf_free_space(root, left);
if (space + push_space * 2 > free_space)
break;
}
}
if (path->slots[0] == i)
push_space += data_size + sizeof(*item);
......@@ -1973,6 +2008,7 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
this_item_size = btrfs_item_size(left, item);
if (this_item_size + sizeof(*item) + push_space > free_space)
break;
push_items++;
push_space += this_item_size + sizeof(*item);
if (i == 0)
......@@ -2046,6 +2082,9 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
btrfs_mark_buffer_dirty(left);
btrfs_mark_buffer_dirty(right);
ret = btrfs_update_ref(trans, root, left, right, 0, push_items);
BUG_ON(ret);
btrfs_item_key(right, &disk_key, 0);
btrfs_set_node_key(upper, &disk_key, slot + 1);
btrfs_mark_buffer_dirty(upper);
......@@ -2147,6 +2186,16 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
KM_USER1);
}
if (!empty && push_items > 0) {
if (path->slots[0] < i)
break;
if (path->slots[0] == i) {
int space = btrfs_leaf_free_space(root, right);
if (space + push_space * 2 > free_space)
break;
}
}
if (path->slots[0] == i)
push_space += data_size + sizeof(*item);
......@@ -2255,6 +2304,10 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
if (right_nritems)
btrfs_mark_buffer_dirty(right);
ret = btrfs_update_ref(trans, root, right, left,
old_left_nritems, push_items);
BUG_ON(ret);
btrfs_item_key(right, &disk_key, 0);
wret = fixup_low_keys(trans, root, path, &disk_key, 1);
if (wret)
......@@ -2294,7 +2347,6 @@ static noinline int split_leaf(struct btrfs_trans_handle *trans,
struct btrfs_path *path, int data_size,
int extend)
{
u64 root_gen;
struct extent_buffer *l;
u32 nritems;
int mid;
......@@ -2313,11 +2365,6 @@ static noinline int split_leaf(struct btrfs_trans_handle *trans,
if (extend)
space_needed = data_size;
if (root->ref_cows)
root_gen = trans->transid;
else
root_gen = 0;
/* first try to make some room by pushing left and right */
if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
wret = push_leaf_right(trans, root, path, data_size, 0);
......@@ -2348,13 +2395,10 @@ again:
nritems = btrfs_header_nritems(l);
mid = (nritems + 1)/ 2;
btrfs_item_key(l, &disk_key, 0);
right = btrfs_alloc_free_block(trans, root, root->leafsize,
root->root_key.objectid,
root_gen,
le64_to_cpu(disk_key.objectid),
0, l->start, 0);
path->nodes[1]->start,
root->root_key.objectid,
trans->transid, 0, l->start, 0);
if (IS_ERR(right)) {
BUG_ON(1);
return PTR_ERR(right);
......@@ -2485,6 +2529,9 @@ again:
btrfs_mark_buffer_dirty(l);
BUG_ON(path->slots[0] != slot);
ret = btrfs_update_ref(trans, root, l, right, 0, nritems);
BUG_ON(ret);
if (mid <= slot) {
btrfs_tree_unlock(path->nodes[0]);
free_extent_buffer(path->nodes[0]);
......@@ -2956,6 +3003,7 @@ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
ret = wret;
wret = btrfs_free_extent(trans, root,
leaf->start, leaf->len,
path->nodes[1]->start,
btrfs_header_owner(path->nodes[1]),
root_gen, 0, 0, 1);
if (wret)
......@@ -3007,7 +3055,7 @@ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
free_extent_buffer(leaf);
wret = btrfs_free_extent(trans, root, bytenr,
blocksize,
blocksize, path->nodes[1]->start,
btrfs_header_owner(path->nodes[1]),
root_gen, 0, 0, 1);
if (wret)
......
......@@ -40,7 +40,7 @@ extern struct kmem_cache *btrfs_bit_radix_cachep;
extern struct kmem_cache *btrfs_path_cachep;
struct btrfs_ordered_sum;
#define BTRFS_MAGIC "_B8RfS_M"
#define BTRFS_MAGIC "_B9RfS_M"
#define BTRFS_ACL_NOT_CACHED ((void *)-1)
......@@ -81,6 +81,9 @@ struct btrfs_ordered_sum;
#define BTRFS_TREE_LOG_OBJECTID -6ULL
#define BTRFS_TREE_LOG_FIXUP_OBJECTID -7ULL
/* dummy objectid represents multiple objectids */
#define BTRFS_MULTIPLE_OBJECTIDS -255ULL
/*
* All files have objectids in this range.
*/
......@@ -369,6 +372,7 @@ struct btrfs_extent_ref {
__le64 generation;
__le64 objectid;
__le64 offset;
__le32 num_refs;
} __attribute__ ((__packed__));
/* dev extents record free space on individual devices. The owner
......@@ -1047,9 +1051,6 @@ btrfs_inode_otime(struct btrfs_inode_item *inode_item)
BTRFS_SETGET_FUNCS(timespec_sec, struct btrfs_timespec, sec, 64);
BTRFS_SETGET_FUNCS(timespec_nsec, struct btrfs_timespec, nsec, 32);
/* struct btrfs_extent_item */
BTRFS_SETGET_FUNCS(extent_refs, struct btrfs_extent_item, refs, 32);
/* struct btrfs_dev_extent */
BTRFS_SETGET_FUNCS(dev_extent_chunk_tree, struct btrfs_dev_extent,
chunk_tree, 64);
......@@ -1070,14 +1071,20 @@ BTRFS_SETGET_FUNCS(ref_root, struct btrfs_extent_ref, root, 64);
BTRFS_SETGET_FUNCS(ref_generation, struct btrfs_extent_ref, generation, 64);
BTRFS_SETGET_FUNCS(ref_objectid, struct btrfs_extent_ref, objectid, 64);
BTRFS_SETGET_FUNCS(ref_offset, struct btrfs_extent_ref, offset, 64);
BTRFS_SETGET_FUNCS(ref_num_refs, struct btrfs_extent_ref, num_refs, 32);
BTRFS_SETGET_STACK_FUNCS(stack_ref_root, struct btrfs_extent_ref, root, 64);
BTRFS_SETGET_STACK_FUNCS(stack_ref_generation, struct btrfs_extent_ref,
generation, 64);
BTRFS_SETGET_STACK_FUNCS(stack_ref_objectid, struct btrfs_extent_ref,
objectid, 64);
BTRFS_SETGET_STACK_FUNCS(stack_ref_offset, struct btrfs_extent_ref, offset, 64);
BTRFS_SETGET_STACK_FUNCS(stack_ref_offset, struct btrfs_extent_ref,
offset, 64);
BTRFS_SETGET_STACK_FUNCS(stack_ref_num_refs, struct btrfs_extent_ref,
num_refs, 32);
/* struct btrfs_extent_item */
BTRFS_SETGET_FUNCS(extent_refs, struct btrfs_extent_item, refs, 32);
BTRFS_SETGET_STACK_FUNCS(stack_extent_refs, struct btrfs_extent_item,
refs, 32);
......@@ -1474,8 +1481,7 @@ static inline struct dentry *fdentry(struct file *file) {
}
/* extent-tree.c */
int btrfs_lookup_extent(struct btrfs_root *root, struct btrfs_path *path,
u64 start, u64 len);
int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len);
int btrfs_update_pinned_extents(struct btrfs_root *root,
u64 bytenr, u64 num, int pin);
int btrfs_drop_leaf_ref(struct btrfs_trans_handle *trans,
......@@ -1495,10 +1501,9 @@ struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
int data, int owner);
struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u32 blocksize,
u32 blocksize, u64 parent,
u64 root_objectid,
u64 ref_generation,
u64 first_objectid,
int level,
u64 hint,
u64 empty_size);
......@@ -1508,23 +1513,24 @@ struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 new_size);
int btrfs_insert_extent_backref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 bytenr,
struct btrfs_path *path,
u64 bytenr, u64 parent,
u64 root_objectid, u64 ref_generation,
u64 owner, u64 owner_offset);
int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 num_bytes, u64 min_bytes,
u64 num_bytes, u64 parent, u64 min_bytes,
u64 root_objectid, u64 ref_generation,
u64 owner, u64 owner_offset,
u64 empty_size, u64 hint_byte,
u64 search_end, struct btrfs_key *ins, u64 data);
int btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_root *root, u64 parent,
u64 root_objectid, u64 ref_generation,
u64 owner, u64 owner_offset,
struct btrfs_key *ins);
int btrfs_alloc_logged_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_root *root, u64 parent,
u64 root_objectid, u64 ref_generation,
u64 owner, u64 owner_offset,
struct btrfs_key *ins);
......@@ -1535,9 +1541,16 @@ int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
u64 search_end, struct btrfs_key *ins,
u64 data);
int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct extent_buffer *buf, int cache_ref);
int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
*root, u64 bytenr, u64 num_bytes,
struct extent_buffer *orig_buf, struct extent_buffer *buf,
u32 *nr_extents);
int btrfs_cache_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct extent_buffer *buf, u32 nr_extents);
int btrfs_update_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct extent_buffer *orig_buf,
struct extent_buffer *buf, int start_slot, int nr);