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Btrfs: Tune readahead during defrag to avoid reading too much at once

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Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2008-01-24 16:13:14 -05:00
parent d1310b2e0c
commit bea495e5b4
1 changed files with 28 additions and 13 deletions
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41
fs/btrfs/extent-tree.c
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@ -1856,27 +1856,44 @@ static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
}
static void noinline reada_walk_down(struct btrfs_root *root,
struct extent_buffer *node)
struct extent_buffer *node,
int slot)
{
int i;
u32 nritems;
u64 bytenr;
int ret;
u64 last = 0;
u32 nritems;
u32 refs;
int level;
u32 blocksize;
int ret;
int i;
int level;
int skipped = 0;
nritems = btrfs_header_nritems(node);
level = btrfs_header_level(node);
for (i = 0; i < nritems; i++) {
if (level)
return;
for (i = slot; i < nritems && skipped < 32; i++) {
bytenr = btrfs_node_blockptr(node, i);
blocksize = btrfs_level_size(root, level - 1);
ret = lookup_extent_ref(NULL, root, bytenr, blocksize, &refs);
BUG_ON(ret);
if (refs != 1)
if (last && ((bytenr > last && bytenr - last > 32 * 1024) ||
(last > bytenr && last - bytenr > 32 * 1024))) {
skipped++;
continue;
}
blocksize = btrfs_level_size(root, level - 1);
if (i != slot) {
ret = lookup_extent_ref(NULL, root, bytenr,
blocksize, &refs);
BUG_ON(ret);
if (refs != 1) {
skipped++;
continue;
}
}
mutex_unlock(&root->fs_info->fs_mutex);
ret = readahead_tree_block(root, bytenr, blocksize);
last = bytenr + blocksize;
cond_resched();
mutex_lock(&root->fs_info->fs_mutex);
if (ret)
@ -1919,9 +1936,6 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
WARN_ON(*level >= BTRFS_MAX_LEVEL);
cur = path->nodes[*level];
if (*level > 0 && path->slots[*level] == 0)
reada_walk_down(root, cur);
if (btrfs_header_level(cur) != *level)
WARN_ON(1);
@ -1951,6 +1965,7 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
next = btrfs_find_tree_block(root, bytenr, blocksize);
if (!next || !btrfs_buffer_uptodate(next)) {
free_extent_buffer(next);
reada_walk_down(root, cur, path->slots[*level]);
mutex_unlock(&root->fs_info->fs_mutex);
next = read_tree_block(root, bytenr, blocksize);
mutex_lock(&root->fs_info->fs_mutex);