Btrfs: Add a write ahead tree log to optimize synchronous operations
File syncs and directory syncs are optimized by copying their
items into a special (copy-on-write) log tree. There is one log tree per
subvolume and the btrfs super block points to a tree of log tree roots.
After a crash, items are copied out of the log tree and back into the
subvolume. See tree-log.c for all the details.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 7114faa..5791240 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -60,7 +60,7 @@
kmem_cache_free(btrfs_path_cachep, p);
}
-void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
+void noinline btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
{
int i;
@@ -176,7 +176,7 @@
return 0;
}
-int __btrfs_cow_block(struct btrfs_trans_handle *trans,
+int noinline __btrfs_cow_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf,
struct extent_buffer *parent, int parent_slot,
@@ -294,7 +294,7 @@
return 0;
}
-int btrfs_cow_block(struct btrfs_trans_handle *trans,
+int noinline btrfs_cow_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct extent_buffer *buf,
struct extent_buffer *parent, int parent_slot,
struct extent_buffer **cow_ret, u64 prealloc_dest)
@@ -677,9 +677,10 @@
*
* slot may point to max if the key is bigger than all of the keys
*/
-static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
- int item_size, struct btrfs_key *key,
- int max, int *slot)
+static noinline int generic_bin_search(struct extent_buffer *eb,
+ unsigned long p,
+ int item_size, struct btrfs_key *key,
+ int max, int *slot)
{
int low = 0;
int high = max;
@@ -765,7 +766,7 @@
return -1;
}
-static struct extent_buffer *read_node_slot(struct btrfs_root *root,
+static noinline struct extent_buffer *read_node_slot(struct btrfs_root *root,
struct extent_buffer *parent, int slot)
{
int level = btrfs_header_level(parent);
@@ -781,7 +782,7 @@
btrfs_node_ptr_generation(parent, slot));
}
-static int balance_level(struct btrfs_trans_handle *trans,
+static noinline int balance_level(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, int level)
{
@@ -1128,8 +1129,9 @@
/*
* readahead one full node of leaves
*/
-static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
- int level, int slot, u64 objectid)
+static noinline void reada_for_search(struct btrfs_root *root,
+ struct btrfs_path *path,
+ int level, int slot, u64 objectid)
{
struct extent_buffer *node;
struct btrfs_disk_key disk_key;
@@ -1201,7 +1203,8 @@
}
}
-static void unlock_up(struct btrfs_path *path, int level, int lowest_unlock)
+static noinline void unlock_up(struct btrfs_path *path, int level,
+ int lowest_unlock)
{
int i;
int skip_level = level;
@@ -1759,8 +1762,9 @@
*
* returns 0 on success and < 0 on failure
*/
-static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
- *root, struct btrfs_path *path, int level)
+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;
@@ -1874,7 +1878,8 @@
* the start of the leaf data. IOW, how much room
* the leaf has left for both items and data
*/
-int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
+int noinline btrfs_leaf_free_space(struct btrfs_root *root,
+ struct extent_buffer *leaf)
{
int nritems = btrfs_header_nritems(leaf);
int ret;
@@ -2283,9 +2288,11 @@
*
* returns 0 if all went well and < 0 on failure.
*/
-static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
- *root, struct btrfs_key *ins_key,
- struct btrfs_path *path, int data_size, int extend)
+static noinline int split_leaf(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_key *ins_key,
+ struct btrfs_path *path, int data_size,
+ int extend)
{
u64 root_gen;
struct extent_buffer *l;
@@ -3079,6 +3086,7 @@
* was nothing in the tree that matched the search criteria.
*/
int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
+ struct btrfs_key *max_key,
struct btrfs_path *path, int cache_only,
u64 min_trans)
{
@@ -3093,6 +3101,7 @@
again:
cur = btrfs_lock_root_node(root);
level = btrfs_header_level(cur);
+ WARN_ON(path->nodes[level]);
path->nodes[level] = cur;
path->locks[level] = 1;
@@ -3107,6 +3116,8 @@
/* at level = 0, we're done, setup the path and exit */
if (level == 0) {
+ if (slot >= nritems)
+ goto find_next_key;
ret = 0;
path->slots[level] = slot;
btrfs_item_key_to_cpu(cur, &found_key, slot);
@@ -3123,6 +3134,8 @@
u64 blockptr;
u64 gen;
struct extent_buffer *tmp;
+ struct btrfs_disk_key disk_key;
+
blockptr = btrfs_node_blockptr(cur, slot);
gen = btrfs_node_ptr_generation(cur, slot);
if (gen < min_trans) {
@@ -3132,6 +3145,14 @@
if (!cache_only)
break;
+ if (max_key) {
+ btrfs_node_key(cur, &disk_key, slot);
+ if (comp_keys(&disk_key, max_key) >= 0) {
+ ret = 1;
+ goto out;
+ }
+ }
+
tmp = btrfs_find_tree_block(root, blockptr,
btrfs_level_size(root, level - 1));
@@ -3143,14 +3164,16 @@
free_extent_buffer(tmp);
slot++;
}
+find_next_key:
/*
* we didn't find a candidate key in this node, walk forward
* and find another one
*/
if (slot >= nritems) {
- ret = btrfs_find_next_key(root, path, min_key, level,
+ path->slots[level] = slot;
+ sret = btrfs_find_next_key(root, path, min_key, level,
cache_only, min_trans);
- if (ret == 0) {
+ if (sret == 0) {
btrfs_release_path(root, path);
goto again;
} else {
@@ -3351,6 +3374,7 @@
{
struct btrfs_key found_key;
struct extent_buffer *leaf;
+ u32 nritems;
int ret;
while(1) {
@@ -3362,9 +3386,20 @@
path->slots[0]--;
}
leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ if (nritems == 0)
+ return 1;
+ if (path->slots[0] == nritems)
+ path->slots[0]--;
+
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
if (found_key.type == type)
return 0;
+ if (found_key.objectid < min_objectid)
+ break;
+ if (found_key.objectid == min_objectid &&
+ found_key.type < type)
+ break;
}
return 1;
}