ocfs2: Fix extent lookup to return true size of holes
Initially, we had wired things to return a size '1' of holes. Cook up a
small amount of code to find the next extent and calculate the number of
clusters between the virtual offset and the next allocated extent.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c
index eef6c18..f35e04f 100644
--- a/fs/ocfs2/extent_map.c
+++ b/fs/ocfs2/extent_map.c
@@ -39,6 +39,97 @@
#include "buffer_head_io.h"
/*
+ * Return the 1st index within el which contains an extent start
+ * larger than v_cluster.
+ */
+static int ocfs2_search_for_hole_index(struct ocfs2_extent_list *el,
+ u32 v_cluster)
+{
+ int i;
+ struct ocfs2_extent_rec *rec;
+
+ for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
+ rec = &el->l_recs[i];
+
+ if (v_cluster < le32_to_cpu(rec->e_cpos))
+ break;
+ }
+
+ return i;
+}
+
+/*
+ * Figure out the size of a hole which starts at v_cluster within the given
+ * extent list.
+ *
+ * If there is no more allocation past v_cluster, we return the maximum
+ * cluster size minus v_cluster.
+ *
+ * If we have in-inode extents, then el points to the dinode list and
+ * eb_bh is NULL. Otherwise, eb_bh should point to the extent block
+ * containing el.
+ */
+static int ocfs2_figure_hole_clusters(struct inode *inode,
+ struct ocfs2_extent_list *el,
+ struct buffer_head *eb_bh,
+ u32 v_cluster,
+ u32 *num_clusters)
+{
+ int ret, i;
+ struct buffer_head *next_eb_bh = NULL;
+ struct ocfs2_extent_block *eb, *next_eb;
+
+ i = ocfs2_search_for_hole_index(el, v_cluster);
+
+ if (i == le16_to_cpu(el->l_next_free_rec) && eb_bh) {
+ eb = (struct ocfs2_extent_block *)eb_bh->b_data;
+
+ /*
+ * Check the next leaf for any extents.
+ */
+
+ if (le64_to_cpu(eb->h_next_leaf_blk) == 0ULL)
+ goto no_more_extents;
+
+ ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
+ le64_to_cpu(eb->h_next_leaf_blk),
+ &next_eb_bh, OCFS2_BH_CACHED, inode);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+ next_eb = (struct ocfs2_extent_block *)next_eb_bh->b_data;
+
+ if (!OCFS2_IS_VALID_EXTENT_BLOCK(next_eb)) {
+ ret = -EROFS;
+ OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, next_eb);
+ goto out;
+ }
+
+ el = &next_eb->h_list;
+
+ i = ocfs2_search_for_hole_index(el, v_cluster);
+ }
+
+no_more_extents:
+ if (i == le16_to_cpu(el->l_next_free_rec)) {
+ /*
+ * We're at the end of our existing allocation. Just
+ * return the maximum number of clusters we could
+ * possibly allocate.
+ */
+ *num_clusters = UINT_MAX - v_cluster;
+ } else {
+ *num_clusters = le32_to_cpu(el->l_recs[i].e_cpos) - v_cluster;
+ }
+
+ ret = 0;
+out:
+ brelse(next_eb_bh);
+ return ret;
+}
+
+/*
* Return the index of the extent record which contains cluster #v_cluster.
* -1 is returned if it was not found.
*
@@ -117,11 +208,19 @@
if (i == -1) {
/*
* A hole was found. Return some canned values that
- * callers can key on.
+ * callers can key on. If asked for, num_clusters will
+ * be populated with the size of the hole.
*/
*p_cluster = 0;
- if (num_clusters)
- *num_clusters = 1;
+ if (num_clusters) {
+ ret = ocfs2_figure_hole_clusters(inode, el, eb_bh,
+ v_cluster,
+ num_clusters);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+ }
} else {
rec = &el->l_recs[i];
@@ -162,7 +261,7 @@
* all while the map is in the process of being updated.
*/
int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
- int *ret_count, unsigned int *extent_flags)
+ u64 *ret_count, unsigned int *extent_flags)
{
int ret;
int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);