Btrfs: Add btree locking to the tree defragmentation code
The online btree defragger is simplified and rewritten to use
standard btree searches instead of a walk up / down mechanism.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/tree-defrag.c b/fs/btrfs/tree-defrag.c
index fab851d..1677e4e 100644
--- a/fs/btrfs/tree-defrag.c
+++ b/fs/btrfs/tree-defrag.c
@@ -21,167 +21,26 @@
#include "disk-io.h"
#include "print-tree.h"
#include "transaction.h"
-
-static void reada_defrag(struct btrfs_root *root,
- struct extent_buffer *node)
-{
- int i;
- u32 nritems;
- u64 bytenr;
- u64 gen;
- u32 blocksize;
- int ret;
-
- blocksize = btrfs_level_size(root, btrfs_header_level(node) - 1);
- nritems = btrfs_header_nritems(node);
- for (i = 0; i < nritems; i++) {
- bytenr = btrfs_node_blockptr(node, i);
- gen = btrfs_node_ptr_generation(node, i);
- ret = readahead_tree_block(root, bytenr, blocksize, gen);
- if (ret)
- break;
- }
-}
-
-static int defrag_walk_down(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
- struct btrfs_path *path, int *level,
- int cache_only, u64 *last_ret)
-{
- struct extent_buffer *next;
- struct extent_buffer *cur;
- u64 bytenr;
- u64 ptr_gen;
- int ret = 0;
- int is_extent = 0;
-
- WARN_ON(*level < 0);
- WARN_ON(*level >= BTRFS_MAX_LEVEL);
-
- if (root->fs_info->extent_root == root)
- is_extent = 1;
-
- if (*level == 1 && cache_only && path->nodes[1] &&
- !btrfs_buffer_defrag(path->nodes[1])) {
- goto out;
- }
- while(*level > 0) {
- WARN_ON(*level < 0);
- WARN_ON(*level >= BTRFS_MAX_LEVEL);
- cur = path->nodes[*level];
-
- if (!cache_only && *level > 1 && path->slots[*level] == 0)
- reada_defrag(root, cur);
-
- if (btrfs_header_level(cur) != *level)
- WARN_ON(1);
-
- if (path->slots[*level] >=
- btrfs_header_nritems(cur))
- break;
-
- if (*level == 1) {
- WARN_ON(btrfs_header_generation(path->nodes[*level]) !=
- trans->transid);
- ret = btrfs_realloc_node(trans, root,
- path->nodes[*level],
- path->slots[*level],
- cache_only, last_ret,
- &root->defrag_progress);
- if (is_extent)
- btrfs_extent_post_op(trans, root);
-
- break;
- }
- bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
- ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
-
- if (cache_only) {
- next = btrfs_find_tree_block(root, bytenr,
- btrfs_level_size(root, *level - 1));
- if (!next || !btrfs_buffer_uptodate(next, ptr_gen) ||
- !btrfs_buffer_defrag(next)) {
- free_extent_buffer(next);
- path->slots[*level]++;
- continue;
- }
- } else {
- next = read_tree_block(root, bytenr,
- btrfs_level_size(root, *level - 1),
- ptr_gen);
- }
- ret = btrfs_cow_block(trans, root, next, path->nodes[*level],
- path->slots[*level], &next);
- BUG_ON(ret);
- if (is_extent)
- btrfs_extent_post_op(trans, root);
-
- WARN_ON(*level <= 0);
- if (path->nodes[*level-1])
- free_extent_buffer(path->nodes[*level-1]);
- path->nodes[*level-1] = next;
- *level = btrfs_header_level(next);
- path->slots[*level] = 0;
- }
- WARN_ON(*level < 0);
- WARN_ON(*level >= BTRFS_MAX_LEVEL);
-
- btrfs_clear_buffer_defrag(path->nodes[*level]);
-out:
- free_extent_buffer(path->nodes[*level]);
- path->nodes[*level] = NULL;
- *level += 1;
- WARN_ON(ret && ret != -EAGAIN);
- return ret;
-}
-
-static int defrag_walk_up(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
- struct btrfs_path *path, int *level,
- int cache_only)
-{
- int i;
- int slot;
- struct extent_buffer *node;
-
- for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
- slot = path->slots[i];
- if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
- path->slots[i]++;
- *level = i;
- node = path->nodes[i];
- WARN_ON(i == 0);
- btrfs_node_key_to_cpu(node, &root->defrag_progress,
- path->slots[i]);
- root->defrag_level = i;
- return 0;
- } else {
- btrfs_clear_buffer_defrag(path->nodes[*level]);
- free_extent_buffer(path->nodes[*level]);
- path->nodes[*level] = NULL;
- *level = i + 1;
- }
- }
- return 1;
-}
+#include "locking.h"
int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
struct btrfs_root *root, int cache_only)
{
struct btrfs_path *path = NULL;
- struct extent_buffer *tmp;
+ struct btrfs_key key;
int ret = 0;
int wret;
int level;
int orig_level;
int i;
int is_extent = 0;
+ int next_key_ret = 0;
u64 last_ret = 0;
- if (root->fs_info->extent_root == root)
+ if (root->fs_info->extent_root == root) {
+ mutex_lock(&root->fs_info->alloc_mutex);
is_extent = 1;
-
- goto out;
+ }
if (root->ref_cows == 0 && !is_extent)
goto out;
@@ -200,67 +59,63 @@
goto out;
}
if (root->defrag_progress.objectid == 0) {
+ struct extent_buffer *root_node;
u32 nritems;
- nritems = btrfs_header_nritems(root->node);
+ root_node = btrfs_lock_root_node(root);
+ nritems = btrfs_header_nritems(root_node);
root->defrag_max.objectid = 0;
/* from above we know this is not a leaf */
- btrfs_node_key_to_cpu(root->node, &root->defrag_max,
+ btrfs_node_key_to_cpu(root_node, &root->defrag_max,
nritems - 1);
- extent_buffer_get(root->node);
- ret = btrfs_cow_block(trans, root, root->node, NULL, 0, &tmp);
- BUG_ON(ret);
- path->nodes[level] = root->node;
- path->slots[level] = 0;
- if (is_extent)
- btrfs_extent_post_op(trans, root);
+ btrfs_tree_unlock(root_node);
+ free_extent_buffer(root_node);
+ memset(&key, 0, sizeof(key));
} else {
- level = root->defrag_level;
- path->lowest_level = level;
- wret = btrfs_search_slot(trans, root, &root->defrag_progress,
- path, 0, 1);
-
- if (is_extent)
- btrfs_extent_post_op(trans, root);
-
- if (wret < 0) {
- ret = wret;
- goto out;
- }
-
- while(level > 0 && !path->nodes[level])
- level--;
-
- if (!path->nodes[level]) {
- ret = 0;
- goto out;
- }
+ memcpy(&key, &root->defrag_progress, sizeof(key));
}
- while(1) {
- wret = defrag_walk_down(trans, root, path, &level, cache_only,
- &last_ret);
- if (wret > 0)
- break;
- if (wret < 0)
- ret = wret;
+ path->lowest_level = 1;
+ path->keep_locks = 1;
+ wret = btrfs_search_slot(trans, root, &key, path, 0, 1);
- wret = defrag_walk_up(trans, root, path, &level, cache_only);
- if (wret > 0)
- break;
- if (wret < 0)
- ret = wret;
- else
- ret = -EAGAIN;
- break;
+ if (wret < 0) {
+ ret = wret;
+ goto out;
}
- for (i = 0; i <= orig_level; i++) {
+ if (!path->nodes[1]) {
+ ret = 0;
+ goto out;
+ }
+ path->slots[1] = btrfs_header_nritems(path->nodes[1]);
+ next_key_ret = btrfs_find_next_key(root, path, &key, 1);
+ ret = btrfs_realloc_node(trans, root,
+ path->nodes[1], 0,
+ cache_only, &last_ret,
+ &root->defrag_progress);
+ WARN_ON(ret && ret != -EAGAIN);
+ if (next_key_ret == 0) {
+ memcpy(&root->defrag_progress, &key, sizeof(key));
+ ret = -EAGAIN;
+ }
+
+ for (i = 1; i < BTRFS_MAX_LEVEL; i++) {
+ if (path->locks[i]) {
+ btrfs_tree_unlock(path->nodes[i]);
+ path->locks[i] = 0;
+ }
if (path->nodes[i]) {
free_extent_buffer(path->nodes[i]);
path->nodes[i] = NULL;
}
}
+ if (is_extent)
+ btrfs_extent_post_op(trans, root);
+
out:
+ if (is_extent)
+ mutex_unlock(&root->fs_info->alloc_mutex);
+
if (path)
btrfs_free_path(path);
if (ret == -EAGAIN) {