[PATCH 17/39] ocfs2: Optionally limit extent size in ocfs2_insert_extent()

Mark Fasheh
2008-09-24T22:07:53Z

From: Tao Ma <tao.ma@oracle.com>

In xattr bucket, we want to limit the maximum size of a btree leaf,
otherwise we'll lose the benefits of hashing because we'll have to search
large leaves.

So add a new field in ocfs2_extent_tree which indicates the maximum leaf cluster
size we want so that we can prevent ocfs2_insert_extent() from merging the leaf
record even if it is contiguous with an adjacent record.

Other btree types are not affected by this change.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
---
fs/ocfs2/alloc.c | 39 ++++++++++++++++++++++++++++++---------
fs/ocfs2/alloc.h | 5 +++++
2 files changed, 35 insertions(+), 9 deletions(-)

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index 47cdea6..16879bd 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -79,6 +79,7 @@ struct ocfs2_extent_tree {
struct buffer_head *root_bh;
struct ocfs2_extent_list *root_el;
void *private;
+ unsigned int max_leaf_clusters;
};

static void ocfs2_dinode_set_last_eb_blk(struct ocfs2_extent_tree *et,
@@ -220,7 +221,8 @@ static struct ocfs2_extent_tree_operations ocfs2_xattr_tree_et_ops = {
};

static struct ocfs2_extent_tree*
- ocfs2_new_extent_tree(struct buffer_head *bh,
+ ocfs2_new_extent_tree(struct inode *inode,
+ struct buffer_head *bh,
enum ocfs2_extent_tree_type et_type,
void *private)
{
@@ -248,6 +250,8 @@ static struct ocfs2_extent_tree*
(struct ocfs2_xattr_block *)bh->b_data;
et->root_el = &xb->xb_attrs.xb_root.xt_list;
et->eops = &ocfs2_xattr_tree_et_ops;
+ et->max_leaf_clusters = ocfs2_clusters_for_bytes(inode->i_sb,
+ OCFS2_MAX_XATTR_TREE_LEAF_SIZE);
}

return et;
@@ -4118,7 +4122,8 @@ out:
static void ocfs2_figure_contig_type(struct inode *inode,
struct ocfs2_insert_type *insert,
struct ocfs2_extent_list *el,
- struct ocfs2_extent_rec *insert_rec)
+ struct ocfs2_extent_rec *insert_rec,
+ struct ocfs2_extent_tree *et)
{
int i;
enum ocfs2_contig_type contig_type = CONTIG_NONE;
@@ -4134,6 +4139,20 @@ static void ocfs2_figure_contig_type(struct inode *inode,
}
}
insert->ins_contig = contig_type;
+
+ if (insert->ins_contig != CONTIG_NONE) {
+ struct ocfs2_extent_rec *rec =
+ &el->l_recs[insert->ins_contig_index];
+ unsigned int len = le16_to_cpu(rec->e_leaf_clusters) +
+ le16_to_cpu(insert_rec->e_leaf_clusters);
+
+ /*
+ * Caller might want us to limit the size of extents, don't
+ * calculate contiguousness if we might exceed that limit.
+ */
+ if (et->max_leaf_clusters && len > et->max_leaf_clusters)
+ insert->ins_contig = CONTIG_NONE;
+ }
}

/*
@@ -4241,7 +4260,7 @@ static int ocfs2_figure_insert_type(struct inode *inode,
le16_to_cpu(el->l_next_free_rec);

if (!insert->ins_tree_depth) {
- ocfs2_figure_contig_type(inode, insert, el, insert_rec);
+ ocfs2_figure_contig_type(inode, insert, el, insert_rec, et);
ocfs2_figure_appending_type(insert, el, insert_rec);
return 0;
}
@@ -4275,7 +4294,7 @@ static int ocfs2_figure_insert_type(struct inode *inode,
* into two types of appends: simple record append, or a
* rotate inside the tail leaf.
*/
- ocfs2_figure_contig_type(inode, insert, el, insert_rec);
+ ocfs2_figure_contig_type(inode, insert, el, insert_rec, et);

/*
* The insert code isn't quite ready to deal with all cases of
@@ -4411,7 +4430,7 @@ int ocfs2_dinode_insert_extent(struct ocfs2_super *osb,
int status;
struct ocfs2_extent_tree *et = NULL;

- et = ocfs2_new_extent_tree(root_bh, OCFS2_DINODE_EXTENT, NULL);
+ et = ocfs2_new_extent_tree(inode, root_bh, OCFS2_DINODE_EXTENT, NULL);
if (!et) {
status = -ENOMEM;
mlog_errno(status);
@@ -4442,7 +4461,8 @@ int ocfs2_xattr_value_insert_extent(struct ocfs2_super *osb,
int status;
struct ocfs2_extent_tree *et = NULL;

- et = ocfs2_new_extent_tree(root_bh, OCFS2_XATTR_VALUE_EXTENT, private);
+ et = ocfs2_new_extent_tree(inode, root_bh,
+ OCFS2_XATTR_VALUE_EXTENT, private);
if (!et) {
status = -ENOMEM;
mlog_errno(status);
@@ -4472,7 +4492,8 @@ int ocfs2_xattr_tree_insert_extent(struct ocfs2_super *osb,
int status;
struct ocfs2_extent_tree *et = NULL;

- et = ocfs2_new_extent_tree(root_bh, OCFS2_XATTR_TREE_EXTENT, NULL);
+ et = ocfs2_new_extent_tree(inode, root_bh, OCFS2_XATTR_TREE_EXTENT,
+ NULL);
if (!et) {
status = -ENOMEM;
mlog_errno(status);
@@ -4888,7 +4909,7 @@ int ocfs2_mark_extent_written(struct inode *inode, struct buffer_head *root_bh,
goto out;
}

- et = ocfs2_new_extent_tree(root_bh, et_type, private);
+ et = ocfs2_new_extent_tree(inode, root_bh, et_type, private);
if (!et) {
ret = -ENOMEM;
mlog_errno(ret);
@@ -5186,7 +5207,7 @@ int ocfs2_remove_extent(struct inode *inode, struct buffer_head *root_bh,
struct ocfs2_path *path = NULL;
struct ocfs2_extent_tree *et = NULL;

- et = ocfs2_new_extent_tree(root_bh, et_type, private);
+ et = ocfs2_new_extent_tree(inode, root_bh, et_type, private);
if (!et) {
ret = -ENOMEM;
mlog_errno(ret);
diff --git a/fs/ocfs2/alloc.h b/fs/ocfs2/alloc.h
index b8cfc53..ff40c8f 100644
--- a/fs/ocfs2/alloc.h
+++ b/fs/ocfs2/alloc.h
@@ -32,6 +32,11 @@ enum ocfs2_extent_tree_type {
OCFS2_XATTR_TREE_EXTENT,
};

+/*
+ * For xattr tree leaf, we limit the leaf byte size to be 64K.
+ */
+#define OCFS2_MAX_XATTR_TREE_LEAF_SIZE 65536
+
struct ocfs2_alloc_context;
int ocfs2_dinode_insert_extent(struct ocfs2_super *osb,
handle_t *handle,
--
1.5.4.5