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-rw-r--r--fs/ocfs2/refcounttree.c212
1 files changed, 212 insertions, 0 deletions
diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index f7d19f4..e72dbdd 100644
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -2192,3 +2192,215 @@ static int ocfs2_mark_extent_refcounted(struct inode *inode,
out:
return ret;
}
+
+/*
+ * Given some contiguous physical clusters, calculate what we need
+ * for modifying their refcount.
+ */
+static int ocfs2_calc_refcount_meta_credits(struct super_block *sb,
+ struct ocfs2_caching_info *ci,
+ struct buffer_head *ref_root_bh,
+ u64 start_cpos,
+ u32 clusters,
+ int *meta_add,
+ int *credits)
+{
+ int ret = 0, index, ref_blocks = 0, recs_add = 0;
+ u64 cpos = start_cpos;
+ struct ocfs2_refcount_block *rb;
+ struct ocfs2_refcount_rec rec;
+ struct buffer_head *ref_leaf_bh = NULL, *prev_bh = NULL;
+ u32 len;
+
+ mlog(0, "start_cpos %llu, clusters %u\n",
+ (unsigned long long)start_cpos, clusters);
+ while (clusters) {
+ ret = ocfs2_get_refcount_rec(ci, ref_root_bh,
+ cpos, clusters, &rec,
+ &index, &ref_leaf_bh);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ if (ref_leaf_bh != prev_bh) {
+ /*
+ * Now we encounter a new leaf block, so calculate
+ * whether we need to extend the old leaf.
+ */
+ if (prev_bh) {
+ rb = (struct ocfs2_refcount_block *)
+ prev_bh->b_data;
+
+ if (le64_to_cpu(rb->rf_records.rl_used) +
+ recs_add >
+ le16_to_cpu(rb->rf_records.rl_count))
+ ref_blocks++;
+ }
+
+ recs_add = 0;
+ *credits += 1;
+ brelse(prev_bh);
+ prev_bh = ref_leaf_bh;
+ get_bh(prev_bh);
+ }
+
+ rb = (struct ocfs2_refcount_block *)ref_leaf_bh->b_data;
+
+ mlog(0, "recs_add %d,cpos %llu, clusters %u, rec->r_cpos %llu,"
+ "rec->r_clusters %u, rec->r_refcount %u, index %d\n",
+ recs_add, (unsigned long long)cpos, clusters,
+ (unsigned long long)le64_to_cpu(rec.r_cpos),
+ le32_to_cpu(rec.r_clusters),
+ le32_to_cpu(rec.r_refcount), index);
+
+ len = min((u64)cpos + clusters, le64_to_cpu(rec.r_cpos) +
+ le32_to_cpu(rec.r_clusters)) - cpos;
+ /*
+ * If the refcount rec already exist, cool. We just need
+ * to check whether there is a split. Otherwise we just need
+ * to increase the refcount.
+ * If we will insert one, increases recs_add.
+ *
+ * We record all the records which will be inserted to the
+ * same refcount block, so that we can tell exactly whether
+ * we need a new refcount block or not.
+ */
+ if (rec.r_refcount) {
+ /* Check whether we need a split at the beginning. */
+ if (cpos == start_cpos &&
+ cpos != le64_to_cpu(rec.r_cpos))
+ recs_add++;
+
+ /* Check whether we need a split in the end. */
+ if (cpos + clusters < le64_to_cpu(rec.r_cpos) +
+ le32_to_cpu(rec.r_clusters))
+ recs_add++;
+ } else
+ recs_add++;
+
+ brelse(ref_leaf_bh);
+ ref_leaf_bh = NULL;
+ clusters -= len;
+ cpos += len;
+ }
+
+ if (prev_bh) {
+ rb = (struct ocfs2_refcount_block *)prev_bh->b_data;
+
+ if (le64_to_cpu(rb->rf_records.rl_used) + recs_add >
+ le16_to_cpu(rb->rf_records.rl_count))
+ ref_blocks++;
+
+ *credits += 1;
+ }
+
+ if (!ref_blocks)
+ goto out;
+
+ mlog(0, "we need ref_blocks %d\n", ref_blocks);
+ *meta_add += ref_blocks;
+ *credits += ref_blocks;
+
+ /*
+ * So we may need ref_blocks to insert into the tree.
+ * That also means we need to change the b-tree and add that number
+ * of records since we never merge them.
+ * We need one more block for expansion since the new created leaf
+ * block is also full and needs split.
+ */
+ rb = (struct ocfs2_refcount_block *)ref_root_bh->b_data;
+ if (le32_to_cpu(rb->rf_flags) & OCFS2_REFCOUNT_TREE_FL) {
+ struct ocfs2_extent_tree et;
+
+ ocfs2_init_refcount_extent_tree(&et, ci, ref_root_bh);
+ *meta_add += ocfs2_extend_meta_needed(et.et_root_el);
+ *credits += ocfs2_calc_extend_credits(sb,
+ et.et_root_el,
+ ref_blocks);
+ } else {
+ *credits += OCFS2_EXPAND_REFCOUNT_TREE_CREDITS;
+ *meta_add += 1;
+ }
+
+out:
+ brelse(ref_leaf_bh);
+ brelse(prev_bh);
+ return ret;
+}
+
+/*
+ * For refcount tree, we will decrease some contiguous clusters
+ * refcount count, so just go through it to see how many blocks
+ * we gonna touch and whether we need to create new blocks.
+ *
+ * Normally the refcount blocks store these refcount should be
+ * continguous also, so that we can get the number easily.
+ * As for meta_ac, we will at most add split 2 refcount record and
+ * 2 more refcount block, so just check it in a rough way.
+ *
+ * Caller must hold refcount tree lock.
+ */
+int ocfs2_prepare_refcount_change_for_del(struct inode *inode,
+ struct buffer_head *di_bh,
+ u64 phys_blkno,
+ u32 clusters,
+ int *credits,
+ struct ocfs2_alloc_context **meta_ac)
+{
+ int ret, ref_blocks = 0;
+ struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+ struct ocfs2_inode_info *oi = OCFS2_I(inode);
+ struct buffer_head *ref_root_bh = NULL;
+ struct ocfs2_refcount_tree *tree;
+ u64 start_cpos = ocfs2_blocks_to_clusters(inode->i_sb, phys_blkno);
+
+ if (!ocfs2_refcount_tree(OCFS2_SB(inode->i_sb))) {
+ ocfs2_error(inode->i_sb, "Inode %lu want to use refcount "
+ "tree, but the feature bit is not set in the "
+ "super block.", inode->i_ino);
+ ret = -EROFS;
+ goto out;
+ }
+
+ BUG_ON(!(oi->ip_dyn_features & OCFS2_HAS_REFCOUNT_FL));
+
+ ret = ocfs2_get_refcount_tree(OCFS2_SB(inode->i_sb),
+ le64_to_cpu(di->i_refcount_loc), &tree);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ ret = ocfs2_read_refcount_block(&tree->rf_ci,
+ le64_to_cpu(di->i_refcount_loc),
+ &ref_root_bh);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ ret = ocfs2_calc_refcount_meta_credits(inode->i_sb,
+ &tree->rf_ci,
+ ref_root_bh,
+ start_cpos, clusters,
+ &ref_blocks, credits);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ mlog(0, "reserve new metadata %d, credits = %d\n",
+ ref_blocks, *credits);
+
+ if (ref_blocks) {
+ ret = ocfs2_reserve_new_metadata_blocks(OCFS2_SB(inode->i_sb),
+ ref_blocks, meta_ac);
+ if (ret)
+ mlog_errno(ret);
+ }
+
+out:
+ brelse(ref_root_bh);
+ return ret;
+}
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