ocfs2: CoW refcount tree improvement.
During CoW, if the old extent record is refcounted, we allocate
som new clusters and do CoW. Actually we can have some improvement
here. If the old extent has refcount=1, that means now it is only
used by this file. So we don't need to allocate new clusters, just
remove the refcounted flag and it is OK. We also have to remove
it from the refcount tree while not deleting it.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index 4e7df8b..0a924365 100644
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -2076,7 +2076,8 @@
struct buffer_head *ref_root_bh,
u64 cpos, u32 len,
struct ocfs2_alloc_context *meta_ac,
- struct ocfs2_cached_dealloc_ctxt *dealloc)
+ struct ocfs2_cached_dealloc_ctxt *dealloc,
+ int delete)
{
int ret = 0, index = 0;
struct ocfs2_refcount_rec rec;
@@ -2084,9 +2085,10 @@
struct super_block *sb = ocfs2_metadata_cache_get_super(ci);
struct buffer_head *ref_leaf_bh = NULL;
- mlog(0, "Tree owner %llu, decrease refcount start %llu, len %u\n",
+ mlog(0, "Tree owner %llu, decrease refcount start %llu, "
+ "len %u, delete %u\n",
(unsigned long long)ocfs2_metadata_cache_owner(ci),
- (unsigned long long)cpos, len);
+ (unsigned long long)cpos, len, delete);
while (len) {
ret = ocfs2_get_refcount_rec(ci, ref_root_bh,
@@ -2099,6 +2101,8 @@
r_count = le32_to_cpu(rec.r_refcount);
BUG_ON(r_count == 0);
+ if (!delete)
+ BUG_ON(r_count > 1);
r_len = min((u64)(cpos + len), le64_to_cpu(rec.r_cpos) +
le32_to_cpu(rec.r_clusters)) - cpos;
@@ -2112,7 +2116,7 @@
goto out;
}
- if (le32_to_cpu(rec.r_refcount) == 1) {
+ if (le32_to_cpu(rec.r_refcount) == 1 && delete) {
ret = ocfs2_cache_cluster_dealloc(dealloc,
ocfs2_clusters_to_blocks(sb, cpos),
r_len);
@@ -2137,7 +2141,8 @@
int ocfs2_decrease_refcount(struct inode *inode,
handle_t *handle, u32 cpos, u32 len,
struct ocfs2_alloc_context *meta_ac,
- struct ocfs2_cached_dealloc_ctxt *dealloc)
+ struct ocfs2_cached_dealloc_ctxt *dealloc,
+ int delete)
{
int ret;
u64 ref_blkno;
@@ -2167,7 +2172,7 @@
}
ret = __ocfs2_decrease_refcount(handle, &tree->rf_ci, ref_root_bh,
- cpos, len, meta_ac, dealloc);
+ cpos, len, meta_ac, dealloc, delete);
if (ret)
mlog_errno(ret);
out:
@@ -2974,10 +2979,16 @@
u32 cpos, u32 p_cluster,
u32 num_clusters, unsigned int e_flags)
{
- int ret, credits = 0;
+ int ret, delete, index, credits = 0;
u32 new_bit, new_len;
+ unsigned int set_len;
struct ocfs2_super *osb = OCFS2_SB(sb);
handle_t *handle;
+ struct buffer_head *ref_leaf_bh = NULL;
+ struct ocfs2_refcount_rec rec;
+
+ mlog(0, "cpos %u, p_cluster %u, num_clusters %u, e_flags %u\n",
+ cpos, p_cluster, num_clusters, e_flags);
ret = ocfs2_lock_refcount_allocators(sb, p_cluster, num_clusters,
&context->di_et,
@@ -2998,35 +3009,75 @@
}
while (num_clusters) {
- ret = __ocfs2_claim_clusters(osb, handle, context->data_ac,
- 1, num_clusters,
- &new_bit, &new_len);
+ ret = ocfs2_get_refcount_rec(context->ref_ci,
+ context->ref_root_bh,
+ p_cluster, num_clusters,
+ &rec, &index, &ref_leaf_bh);
if (ret) {
mlog_errno(ret);
goto out_commit;
}
- ret = ocfs2_replace_clusters(handle, context,
- cpos, p_cluster, new_bit,
- new_len, e_flags);
+ BUG_ON(!rec.r_refcount);
+ set_len = min((u64)p_cluster + num_clusters,
+ le64_to_cpu(rec.r_cpos) +
+ le32_to_cpu(rec.r_clusters)) - p_cluster;
+
+ /*
+ * There are many different situation here.
+ * 1. If refcount == 1, remove the flag and don't COW.
+ * 2. If refcount > 1, allocate clusters.
+ * Here we may not allocate r_len once at a time, so continue
+ * until we reach num_clusters.
+ */
+ if (le32_to_cpu(rec.r_refcount) == 1) {
+ delete = 0;
+ ret = ocfs2_clear_ext_refcount(handle, &context->di_et,
+ cpos, p_cluster,
+ set_len, e_flags,
+ context->meta_ac,
+ &context->dealloc);
+ if (ret) {
+ mlog_errno(ret);
+ goto out_commit;
+ }
+ } else {
+ delete = 1;
+
+ ret = __ocfs2_claim_clusters(osb, handle,
+ context->data_ac,
+ 1, set_len,
+ &new_bit, &new_len);
+ if (ret) {
+ mlog_errno(ret);
+ goto out_commit;
+ }
+
+ ret = ocfs2_replace_clusters(handle, context,
+ cpos, p_cluster, new_bit,
+ new_len, e_flags);
+ if (ret) {
+ mlog_errno(ret);
+ goto out_commit;
+ }
+ set_len = new_len;
+ }
+
+ ret = __ocfs2_decrease_refcount(handle, context->ref_ci,
+ context->ref_root_bh,
+ p_cluster, set_len,
+ context->meta_ac,
+ &context->dealloc, delete);
if (ret) {
mlog_errno(ret);
goto out_commit;
}
- cpos += new_len;
- p_cluster += new_len;
- num_clusters -= new_len;
- }
-
- ret = __ocfs2_decrease_refcount(handle, context->ref_ci,
- context->ref_root_bh,
- p_cluster, num_clusters,
- context->meta_ac,
- &context->dealloc);
- if (ret) {
- mlog_errno(ret);
- goto out_commit;
+ cpos += set_len;
+ p_cluster += set_len;
+ num_clusters -= set_len;
+ brelse(ref_leaf_bh);
+ ref_leaf_bh = NULL;
}
/*
@@ -3049,6 +3100,7 @@
ocfs2_free_alloc_context(context->meta_ac);
context->meta_ac = NULL;
}
+ brelse(ref_leaf_bh);
return ret;
}