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Diffstat (limited to 'fs/btrfs/ctree.c')
-rw-r--r--fs/btrfs/ctree.c234
1 files changed, 226 insertions, 8 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 3b6e35aafc9..3af777357ac 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -54,6 +54,31 @@ struct btrfs_path *btrfs_alloc_path(void)
return path;
}
+/*
+ * set all locked nodes in the path to blocking locks. This should
+ * be done before scheduling
+ */
+noinline void btrfs_set_path_blocking(struct btrfs_path *p)
+{
+ int i;
+ for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
+ if (p->nodes[i] && p->locks[i])
+ btrfs_set_lock_blocking(p->nodes[i]);
+ }
+}
+
+/*
+ * reset all the locked nodes in the patch to spinning locks.
+ */
+noinline void btrfs_clear_path_blocking(struct btrfs_path *p)
+{
+ int i;
+ for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
+ if (p->nodes[i] && p->locks[i])
+ btrfs_clear_lock_blocking(p->nodes[i]);
+ }
+}
+
/* this also releases the path */
void btrfs_free_path(struct btrfs_path *p)
{
@@ -272,6 +297,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
if (IS_ERR(cow))
return PTR_ERR(cow);
+ /* cow is set to blocking by btrfs_init_new_buffer */
+
copy_extent_buffer(cow, buf, 0, 0, cow->len);
btrfs_set_header_bytenr(cow, cow->start);
btrfs_set_header_generation(cow, trans->transid);
@@ -397,6 +424,11 @@ noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
}
search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
+
+ if (parent)
+ btrfs_set_lock_blocking(parent);
+ btrfs_set_lock_blocking(buf);
+
ret = __btrfs_cow_block(trans, root, buf, parent,
parent_slot, cow_ret, search_start, 0,
prealloc_dest);
@@ -502,6 +534,8 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
if (parent_nritems == 1)
return 0;
+ btrfs_set_lock_blocking(parent);
+
for (i = start_slot; i < end_slot; i++) {
int close = 1;
@@ -562,6 +596,7 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
search_start = last_block;
btrfs_tree_lock(cur);
+ btrfs_set_lock_blocking(cur);
err = __btrfs_cow_block(trans, root, cur, parent, i,
&cur, search_start,
min(16 * blocksize,
@@ -860,6 +895,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
return 0;
mid = path->nodes[level];
+
WARN_ON(!path->locks[level]);
WARN_ON(btrfs_header_generation(mid) != trans->transid);
@@ -882,6 +918,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
/* promote the child to a root */
child = read_node_slot(root, mid, 0);
btrfs_tree_lock(child);
+ btrfs_set_lock_blocking(child);
BUG_ON(!child);
ret = btrfs_cow_block(trans, root, child, mid, 0, &child, 0);
BUG_ON(ret);
@@ -898,6 +935,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
add_root_to_dirty_list(root);
btrfs_tree_unlock(child);
+
path->locks[level] = 0;
path->nodes[level] = NULL;
clean_tree_block(trans, root, mid);
@@ -922,6 +960,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
left = read_node_slot(root, parent, pslot - 1);
if (left) {
btrfs_tree_lock(left);
+ btrfs_set_lock_blocking(left);
wret = btrfs_cow_block(trans, root, left,
parent, pslot - 1, &left, 0);
if (wret) {
@@ -932,6 +971,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
right = read_node_slot(root, parent, pslot + 1);
if (right) {
btrfs_tree_lock(right);
+ btrfs_set_lock_blocking(right);
wret = btrfs_cow_block(trans, root, right,
parent, pslot + 1, &right, 0);
if (wret) {
@@ -1107,6 +1147,8 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
u32 left_nr;
btrfs_tree_lock(left);
+ btrfs_set_lock_blocking(left);
+
left_nr = btrfs_header_nritems(left);
if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
wret = 1;
@@ -1153,7 +1195,10 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
*/
if (right) {
u32 right_nr;
+
btrfs_tree_lock(right);
+ btrfs_set_lock_blocking(right);
+
right_nr = btrfs_header_nritems(right);
if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
wret = 1;
@@ -1265,6 +1310,68 @@ static noinline void reada_for_search(struct btrfs_root *root,
}
/*
+ * returns -EAGAIN if it had to drop the path, or zero if everything was in
+ * cache
+ */
+static noinline int reada_for_balance(struct btrfs_root *root,
+ struct btrfs_path *path, int level)
+{
+ int slot;
+ int nritems;
+ struct extent_buffer *parent;
+ struct extent_buffer *eb;
+ u64 gen;
+ u64 block1 = 0;
+ u64 block2 = 0;
+ int ret = 0;
+ int blocksize;
+
+ parent = path->nodes[level - 1];
+ if (!parent)
+ return 0;
+
+ nritems = btrfs_header_nritems(parent);
+ slot = path->slots[level];
+ blocksize = btrfs_level_size(root, level);
+
+ if (slot > 0) {
+ block1 = btrfs_node_blockptr(parent, slot - 1);
+ gen = btrfs_node_ptr_generation(parent, slot - 1);
+ eb = btrfs_find_tree_block(root, block1, blocksize);
+ if (eb && btrfs_buffer_uptodate(eb, gen))
+ block1 = 0;
+ free_extent_buffer(eb);
+ }
+ if (slot < nritems) {
+ block2 = btrfs_node_blockptr(parent, slot + 1);
+ gen = btrfs_node_ptr_generation(parent, slot + 1);
+ eb = btrfs_find_tree_block(root, block2, blocksize);
+ if (eb && btrfs_buffer_uptodate(eb, gen))
+ block2 = 0;
+ free_extent_buffer(eb);
+ }
+ if (block1 || block2) {
+ ret = -EAGAIN;
+ btrfs_release_path(root, path);
+ if (block1)
+ readahead_tree_block(root, block1, blocksize, 0);
+ if (block2)
+ readahead_tree_block(root, block2, blocksize, 0);
+
+ if (block1) {
+ eb = read_tree_block(root, block1, blocksize, 0);
+ free_extent_buffer(eb);
+ }
+ if (block1) {
+ eb = read_tree_block(root, block2, blocksize, 0);
+ free_extent_buffer(eb);
+ }
+ }
+ return ret;
+}
+
+
+/*
* when we walk down the tree, it is usually safe to unlock the higher layers
* in the tree. The exceptions are when our path goes through slot 0, because
* operations on the tree might require changing key pointers higher up in the
@@ -1315,6 +1422,32 @@ static noinline void unlock_up(struct btrfs_path *path, int level,
}
/*
+ * This releases any locks held in the path starting at level and
+ * going all the way up to the root.
+ *
+ * btrfs_search_slot will keep the lock held on higher nodes in a few
+ * corner cases, such as COW of the block at slot zero in the node. This
+ * ignores those rules, and it should only be called when there are no
+ * more updates to be done higher up in the tree.
+ */
+noinline void btrfs_unlock_up_safe(struct btrfs_path *path, int level)
+{
+ int i;
+
+ if (path->keep_locks || path->lowest_level)
+ return;
+
+ for (i = level; i < BTRFS_MAX_LEVEL; i++) {
+ if (!path->nodes[i])
+ break;
+ if (!path->locks[i])
+ break;
+ btrfs_tree_unlock(path->nodes[i]);
+ path->locks[i] = 0;
+ }
+}
+
+/*
* look for key in the tree. path is filled in with nodes along the way
* if key is found, we return zero and you can find the item in the leaf
* level of the path (level 0)
@@ -1385,6 +1518,7 @@ again:
*/
if (prealloc_block.objectid &&
prealloc_block.offset != b->len) {
+ btrfs_set_path_blocking(p);
btrfs_free_reserved_extent(root,
prealloc_block.objectid,
prealloc_block.offset);
@@ -1409,6 +1543,8 @@ again:
goto again;
}
+ btrfs_set_path_blocking(p);
+
wret = btrfs_cow_block(trans, root, b,
p->nodes[level + 1],
p->slots[level + 1],
@@ -1430,6 +1566,22 @@ cow_done:
if (!p->skip_locking)
p->locks[level] = 1;
+ btrfs_clear_path_blocking(p);
+
+ /*
+ * 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.
+ *
+ * If cow is true, then we might be changing slot zero,
+ * which may require changing the parent. So, we can't
+ * drop the lock until after we know which slot we're
+ * operating on.
+ */
+ if (!cow)
+ btrfs_unlock_up_safe(p, level + 1);
+
ret = check_block(root, p, level);
if (ret) {
ret = -1;
@@ -1437,6 +1589,7 @@ cow_done:
}
ret = bin_search(b, key, level, &slot);
+
if (level != 0) {
if (ret && slot > 0)
slot -= 1;
@@ -1444,7 +1597,16 @@ cow_done:
if ((p->search_for_split || ins_len > 0) &&
btrfs_header_nritems(b) >=
BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
- int sret = split_node(trans, root, p, level);
+ int sret;
+
+ sret = reada_for_balance(root, p, level);
+ if (sret)
+ goto again;
+
+ btrfs_set_path_blocking(p);
+ sret = split_node(trans, root, p, level);
+ btrfs_clear_path_blocking(p);
+
BUG_ON(sret > 0);
if (sret) {
ret = sret;
@@ -1453,8 +1615,16 @@ cow_done:
b = p->nodes[level];
slot = p->slots[level];
} else if (ins_len < 0) {
- int sret = balance_level(trans, root, p,
- level);
+ int sret;
+
+ sret = reada_for_balance(root, p, level);
+ if (sret)
+ goto again;
+
+ btrfs_set_path_blocking(p);
+ sret = balance_level(trans, root, p, level);
+ btrfs_clear_path_blocking(p);
+
if (sret) {
ret = sret;
goto done;
@@ -1488,7 +1658,7 @@ cow_done:
* of the btree by dropping locks before
* we read.
*/
- if (level > 1) {
+ if (level > 0) {
btrfs_release_path(NULL, p);
if (tmp)
free_extent_buffer(tmp);
@@ -1503,6 +1673,7 @@ cow_done:
free_extent_buffer(tmp);
goto again;
} else {
+ btrfs_set_path_blocking(p);
if (tmp)
free_extent_buffer(tmp);
if (should_reada)
@@ -1512,14 +1683,29 @@ cow_done:
b = read_node_slot(root, b, slot);
}
}
- if (!p->skip_locking)
- btrfs_tree_lock(b);
+ if (!p->skip_locking) {
+ int lret;
+
+ btrfs_clear_path_blocking(p);
+ lret = btrfs_try_spin_lock(b);
+
+ if (!lret) {
+ btrfs_set_path_blocking(p);
+ btrfs_tree_lock(b);
+ btrfs_clear_path_blocking(p);
+ }
+ }
} else {
p->slots[level] = slot;
if (ins_len > 0 &&
btrfs_leaf_free_space(root, b) < ins_len) {
- int sret = split_leaf(trans, root, key,
+ int sret;
+
+ btrfs_set_path_blocking(p);
+ sret = split_leaf(trans, root, key,
p, ins_len, ret == 0);
+ btrfs_clear_path_blocking(p);
+
BUG_ON(sret > 0);
if (sret) {
ret = sret;
@@ -1533,12 +1719,16 @@ cow_done:
}
ret = 1;
done:
+ /*
+ * we don't really know what they plan on doing with the path
+ * from here on, so for now just mark it as blocking
+ */
+ btrfs_set_path_blocking(p);
if (prealloc_block.objectid) {
btrfs_free_reserved_extent(root,
prealloc_block.objectid,
prealloc_block.offset);
}
-
return ret;
}
@@ -1562,6 +1752,8 @@ int btrfs_merge_path(struct btrfs_trans_handle *trans,
ret = btrfs_cow_block(trans, root, eb, NULL, 0, &eb, 0);
BUG_ON(ret);
+ btrfs_set_lock_blocking(eb);
+
parent = eb;
while (1) {
level = btrfs_header_level(parent);
@@ -1586,6 +1778,7 @@ int btrfs_merge_path(struct btrfs_trans_handle *trans,
eb = read_tree_block(root, bytenr, blocksize,
generation);
btrfs_tree_lock(eb);
+ btrfs_set_lock_blocking(eb);
}
/*
@@ -1610,6 +1803,7 @@ int btrfs_merge_path(struct btrfs_trans_handle *trans,
eb = read_tree_block(root, bytenr, blocksize,
generation);
btrfs_tree_lock(eb);
+ btrfs_set_lock_blocking(eb);
}
ret = btrfs_cow_block(trans, root, eb, parent, slot,
@@ -2156,6 +2350,8 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
right = read_node_slot(root, upper, slot + 1);
btrfs_tree_lock(right);
+ btrfs_set_lock_blocking(right);
+
free_space = btrfs_leaf_free_space(root, right);
if (free_space < data_size)
goto out_unlock;
@@ -2351,6 +2547,8 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
left = read_node_slot(root, path->nodes[1], slot - 1);
btrfs_tree_lock(left);
+ btrfs_set_lock_blocking(left);
+
free_space = btrfs_leaf_free_space(root, left);
if (free_space < data_size) {
ret = 1;
@@ -2809,6 +3007,12 @@ int btrfs_split_item(struct btrfs_trans_handle *trans,
path->keep_locks = 0;
BUG_ON(ret);
+ /*
+ * make sure any changes to the path from split_leaf leave it
+ * in a blocking state
+ */
+ btrfs_set_path_blocking(path);
+
leaf = path->nodes[0];
BUG_ON(btrfs_leaf_free_space(root, leaf) < sizeof(struct btrfs_item));
@@ -3338,6 +3542,7 @@ int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
BUG();
}
out:
+ btrfs_unlock_up_safe(path, 1);
return ret;
}
@@ -3705,12 +3910,14 @@ find_next_key:
*/
if (slot >= nritems) {
path->slots[level] = slot;
+ btrfs_set_path_blocking(path);
sret = btrfs_find_next_key(root, path, min_key, level,
cache_only, min_trans);
if (sret == 0) {
btrfs_release_path(root, path);
goto again;
} else {
+ btrfs_clear_path_blocking(path);
goto out;
}
}
@@ -3722,16 +3929,20 @@ find_next_key:
unlock_up(path, level, 1);
goto out;
}
+ btrfs_set_path_blocking(path);
cur = read_node_slot(root, cur, slot);
btrfs_tree_lock(cur);
+
path->locks[level - 1] = 1;
path->nodes[level - 1] = cur;
unlock_up(path, level, 1);
+ btrfs_clear_path_blocking(path);
}
out:
if (ret == 0)
memcpy(min_key, &found_key, sizeof(found_key));
+ btrfs_set_path_blocking(path);
return ret;
}
@@ -3827,6 +4038,7 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
if (ret < 0)
return ret;
+ btrfs_set_path_blocking(path);
nritems = btrfs_header_nritems(path->nodes[0]);
/*
* by releasing the path above we dropped all our locks. A balance
@@ -3857,6 +4069,7 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
free_extent_buffer(next);
}
+ /* the path was set to blocking above */
if (level == 1 && (path->locks[1] || path->skip_locking) &&
path->reada)
reada_for_search(root, path, level, slot, 0);
@@ -3865,6 +4078,7 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
if (!path->skip_locking) {
WARN_ON(!btrfs_tree_locked(c));
btrfs_tree_lock(next);
+ btrfs_set_lock_blocking(next);
}
break;
}
@@ -3881,12 +4095,15 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
path->locks[level] = 1;
if (!level)
break;
+
+ btrfs_set_path_blocking(path);
if (level == 1 && path->locks[1] && path->reada)
reada_for_search(root, path, level, slot, 0);
next = read_node_slot(root, next, 0);
if (!path->skip_locking) {
WARN_ON(!btrfs_tree_locked(path->nodes[level]));
btrfs_tree_lock(next);
+ btrfs_set_lock_blocking(next);
}
}
done:
@@ -3911,6 +4128,7 @@ int btrfs_previous_item(struct btrfs_root *root,
while (1) {
if (path->slots[0] == 0) {
+ btrfs_set_path_blocking(path);
ret = btrfs_prev_leaf(root, path);
if (ret != 0)
return ret;
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-14 23:54:39 +0000