[PATCH 52/62] ocfs2: Add support for cross extent block

From: Mark Fasheh
Date: Wed Apr 02 2008 - 16:38:32 EST

From: Tao Ma <tao.ma@xxxxxxxxxx>

In ocfs2_merge_rec_left, when we find the merge extent is "CONTIG_RIGHT"
with the first extent record of the next extent block, we will merge it to
the next extent block and change all the related extent blocks accordingly.

In ocfs2_merge_rec_right, when we find the merge extent is "CONTIG_LEFT"
with the last extent record of the previous extent block, we will merge
it to the prevoius extent block and change all the related extent blocks
accordingly.

As for CONTIG_LEFTRIGHT, we will handle CONTIG_RIGHT first so that when
the index is zero, the merge process will be more efficient and easier.

Signed-off-by: Tao Ma <tao.ma@xxxxxxxxxx>
Signed-off-by: Mark Fasheh <mfasheh@xxxxxxxx>
---
fs/ocfs2/alloc.c | 366 ++++++++++++++++++++++++++++++++++++++++++++++++------
1 files changed, 325 insertions(+), 41 deletions(-)

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index 447206e..f63cb32 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -1450,6 +1450,8 @@ static void ocfs2_adjust_root_records(struct ocfs2_extent_list *root_el,
* - When our insert into the right path leaf is at the leftmost edge
* and requires an update of the path immediately to it's left. This
* can occur at the end of some types of rotation and appending inserts.
+ * - When we've adjusted the last extent record in the left path leaf and the
+ * 1st extent record in the right path leaf during cross extent block merge.
*/
static void ocfs2_complete_edge_insert(struct inode *inode, handle_t *handle,
struct ocfs2_path *left_path,
@@ -2712,24 +2714,147 @@ static void ocfs2_cleanup_merge(struct ocfs2_extent_list *el,
}
}

+static int ocfs2_get_right_path(struct inode *inode,
+ struct ocfs2_path *left_path,
+ struct ocfs2_path **ret_right_path)
+{
+ int ret;
+ u32 right_cpos;
+ struct ocfs2_path *right_path = NULL;
+ struct ocfs2_extent_list *left_el;
+
+ *ret_right_path = NULL;
+
+ /* This function shouldn't be called for non-trees. */
+ BUG_ON(left_path->p_tree_depth == 0);
+
+ left_el = path_leaf_el(left_path);
+ BUG_ON(left_el->l_next_free_rec != left_el->l_count);
+
+ ret = ocfs2_find_cpos_for_right_leaf(inode->i_sb, left_path,
+ &right_cpos);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ /* This function shouldn't be called for the rightmost leaf. */
+ BUG_ON(right_cpos == 0);
+
+ right_path = ocfs2_new_path(path_root_bh(left_path),
+ path_root_el(left_path));
+ if (!right_path) {
+ ret = -ENOMEM;
+ mlog_errno(ret);
+ goto out;
+ }
+
+ ret = ocfs2_find_path(inode, right_path, right_cpos);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ *ret_right_path = right_path;
+out:
+ if (ret)
+ ocfs2_free_path(right_path);
+ return ret;
+}
+
/*
* Remove split_rec clusters from the record at index and merge them
- * onto the beginning of the record at index + 1.
+ * onto the beginning of the record "next" to it.
+ * For index < l_count - 1, the next means the extent rec at index + 1.
+ * For index == l_count - 1, the "next" means the 1st extent rec of the
+ * next extent block.
*/
-static int ocfs2_merge_rec_right(struct inode *inode, struct buffer_head *bh,
- handle_t *handle,
- struct ocfs2_extent_rec *split_rec,
- struct ocfs2_extent_list *el, int index)
+static int ocfs2_merge_rec_right(struct inode *inode,
+ struct ocfs2_path *left_path,
+ handle_t *handle,
+ struct ocfs2_extent_rec *split_rec,
+ int index)
{
- int ret;
+ int ret, next_free, i;
unsigned int split_clusters = le16_to_cpu(split_rec->e_leaf_clusters);
struct ocfs2_extent_rec *left_rec;
struct ocfs2_extent_rec *right_rec;
+ struct ocfs2_extent_list *right_el;
+ struct ocfs2_path *right_path = NULL;
+ int subtree_index = 0;
+ struct ocfs2_extent_list *el = path_leaf_el(left_path);
+ struct buffer_head *bh = path_leaf_bh(left_path);
+ struct buffer_head *root_bh = NULL;

BUG_ON(index >= le16_to_cpu(el->l_next_free_rec));
-
left_rec = &el->l_recs[index];
- right_rec = &el->l_recs[index + 1];
+
+ if (index == le16_to_cpu(el->l_next_free_rec - 1) &&
+ le16_to_cpu(el->l_next_free_rec) == le16_to_cpu(el->l_count)) {
+ /* we meet with a cross extent block merge. */
+ ret = ocfs2_get_right_path(inode, left_path, &right_path);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ right_el = path_leaf_el(right_path);
+ next_free = le16_to_cpu(right_el->l_next_free_rec);
+ BUG_ON(next_free <= 0);
+ right_rec = &right_el->l_recs[0];
+ if (ocfs2_is_empty_extent(right_rec)) {
+ BUG_ON(le16_to_cpu(next_free) <= 1);
+ right_rec = &right_el->l_recs[1];
+ }
+
+ BUG_ON(le32_to_cpu(left_rec->e_cpos) +
+ le16_to_cpu(left_rec->e_leaf_clusters) !=
+ le32_to_cpu(right_rec->e_cpos));
+
+ subtree_index = ocfs2_find_subtree_root(inode,
+ left_path, right_path);
+
+ ret = ocfs2_extend_rotate_transaction(handle, subtree_index,
+ handle->h_buffer_credits,
+ right_path);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ root_bh = left_path->p_node[subtree_index].bh;
+ BUG_ON(root_bh != right_path->p_node[subtree_index].bh);
+
+ ret = ocfs2_journal_access(handle, inode, root_bh,
+ OCFS2_JOURNAL_ACCESS_WRITE);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ for (i = subtree_index + 1;
+ i < path_num_items(right_path); i++) {
+ ret = ocfs2_journal_access(handle, inode,
+ right_path->p_node[i].bh,
+ OCFS2_JOURNAL_ACCESS_WRITE);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ ret = ocfs2_journal_access(handle, inode,
+ left_path->p_node[i].bh,
+ OCFS2_JOURNAL_ACCESS_WRITE);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+ }
+
+ } else {
+ BUG_ON(index == le16_to_cpu(el->l_next_free_rec) - 1);
+ right_rec = &el->l_recs[index + 1];
+ }

ret = ocfs2_journal_access(handle, inode, bh,
OCFS2_JOURNAL_ACCESS_WRITE);
@@ -2751,30 +2876,156 @@ static int ocfs2_merge_rec_right(struct inode *inode, struct buffer_head *bh,
if (ret)
mlog_errno(ret);

+ if (right_path) {
+ ret = ocfs2_journal_dirty(handle, path_leaf_bh(right_path));
+ if (ret)
+ mlog_errno(ret);
+
+ ocfs2_complete_edge_insert(inode, handle, left_path,
+ right_path, subtree_index);
+ }
+out:
+ if (right_path)
+ ocfs2_free_path(right_path);
+ return ret;
+}
+
+static int ocfs2_get_left_path(struct inode *inode,
+ struct ocfs2_path *right_path,
+ struct ocfs2_path **ret_left_path)
+{
+ int ret;
+ u32 left_cpos;
+ struct ocfs2_path *left_path = NULL;
+
+ *ret_left_path = NULL;
+
+ /* This function shouldn't be called for non-trees. */
+ BUG_ON(right_path->p_tree_depth == 0);
+
+ ret = ocfs2_find_cpos_for_left_leaf(inode->i_sb,
+ right_path, &left_cpos);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ /* This function shouldn't be called for the leftmost leaf. */
+ BUG_ON(left_cpos == 0);
+
+ left_path = ocfs2_new_path(path_root_bh(right_path),
+ path_root_el(right_path));
+ if (!left_path) {
+ ret = -ENOMEM;
+ mlog_errno(ret);
+ goto out;
+ }
+
+ ret = ocfs2_find_path(inode, left_path, left_cpos);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ *ret_left_path = left_path;
out:
+ if (ret)
+ ocfs2_free_path(left_path);
return ret;
}

/*
* Remove split_rec clusters from the record at index and merge them
- * onto the tail of the record at index - 1.
+ * onto the tail of the record "before" it.
+ * For index > 0, the "before" means the extent rec at index - 1.
+ *
+ * For index == 0, the "before" means the last record of the previous
+ * extent block. And there is also a situation that we may need to
+ * remove the rightmost leaf extent block in the right_path and change
+ * the right path to indicate the new rightmost path.
*/
-static int ocfs2_merge_rec_left(struct inode *inode, struct buffer_head *bh,
+static int ocfs2_merge_rec_left(struct inode *inode,
+ struct ocfs2_path *right_path,
handle_t *handle,
struct ocfs2_extent_rec *split_rec,
- struct ocfs2_extent_list *el, int index)
+ struct ocfs2_cached_dealloc_ctxt *dealloc,
+ int index)
{
- int ret, has_empty_extent = 0;
+ int ret, i, subtree_index = 0, has_empty_extent = 0;
unsigned int split_clusters = le16_to_cpu(split_rec->e_leaf_clusters);
struct ocfs2_extent_rec *left_rec;
struct ocfs2_extent_rec *right_rec;
+ struct ocfs2_extent_list *el = path_leaf_el(right_path);
+ struct buffer_head *bh = path_leaf_bh(right_path);
+ struct buffer_head *root_bh = NULL;
+ struct ocfs2_path *left_path = NULL;
+ struct ocfs2_extent_list *left_el;

- BUG_ON(index <= 0);
+ BUG_ON(index < 0);

- left_rec = &el->l_recs[index - 1];
right_rec = &el->l_recs[index];
- if (ocfs2_is_empty_extent(&el->l_recs[0]))
- has_empty_extent = 1;
+ if (index == 0) {
+ /* we meet with a cross extent block merge. */
+ ret = ocfs2_get_left_path(inode, right_path, &left_path);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ left_el = path_leaf_el(left_path);
+ BUG_ON(le16_to_cpu(left_el->l_next_free_rec) !=
+ le16_to_cpu(left_el->l_count));
+
+ left_rec = &left_el->l_recs[
+ le16_to_cpu(left_el->l_next_free_rec) - 1];
+ BUG_ON(le32_to_cpu(left_rec->e_cpos) +
+ le16_to_cpu(left_rec->e_leaf_clusters) !=
+ le32_to_cpu(split_rec->e_cpos));
+
+ subtree_index = ocfs2_find_subtree_root(inode,
+ left_path, right_path);
+
+ ret = ocfs2_extend_rotate_transaction(handle, subtree_index,
+ handle->h_buffer_credits,
+ left_path);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ root_bh = left_path->p_node[subtree_index].bh;
+ BUG_ON(root_bh != right_path->p_node[subtree_index].bh);
+
+ ret = ocfs2_journal_access(handle, inode, root_bh,
+ OCFS2_JOURNAL_ACCESS_WRITE);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ for (i = subtree_index + 1;
+ i < path_num_items(right_path); i++) {
+ ret = ocfs2_journal_access(handle, inode,
+ right_path->p_node[i].bh,
+ OCFS2_JOURNAL_ACCESS_WRITE);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ ret = ocfs2_journal_access(handle, inode,
+ left_path->p_node[i].bh,
+ OCFS2_JOURNAL_ACCESS_WRITE);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+ }
+ } else {
+ left_rec = &el->l_recs[index - 1];
+ if (ocfs2_is_empty_extent(&el->l_recs[0]))
+ has_empty_extent = 1;
+ }

ret = ocfs2_journal_access(handle, inode, bh,
OCFS2_JOURNAL_ACCESS_WRITE);
@@ -2790,9 +3041,8 @@ static int ocfs2_merge_rec_left(struct inode *inode, struct buffer_head *bh,
*left_rec = *split_rec;

has_empty_extent = 0;
- } else {
+ } else
le16_add_cpu(&left_rec->e_leaf_clusters, split_clusters);
- }

le32_add_cpu(&right_rec->e_cpos, split_clusters);
le64_add_cpu(&right_rec->e_blkno,
@@ -2805,13 +3055,44 @@ static int ocfs2_merge_rec_left(struct inode *inode, struct buffer_head *bh,
if (ret)
mlog_errno(ret);

+ if (left_path) {
+ ret = ocfs2_journal_dirty(handle, path_leaf_bh(left_path));
+ if (ret)
+ mlog_errno(ret);
+
+ /*
+ * In the situation that the right_rec is empty and the extent
+ * block is empty also, ocfs2_complete_edge_insert can't handle
+ * it and we need to delete the right extent block.
+ */
+ if (le16_to_cpu(right_rec->e_leaf_clusters) == 0 &&
+ le16_to_cpu(el->l_next_free_rec) == 1) {
+
+ ret = ocfs2_remove_rightmost_path(inode, handle,
+ right_path, dealloc);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ /* Now the rightmost extent block has been deleted.
+ * So we use the new rightmost path.
+ */
+ ocfs2_mv_path(right_path, left_path);
+ left_path = NULL;
+ } else
+ ocfs2_complete_edge_insert(inode, handle, left_path,
+ right_path, subtree_index);
+ }
out:
+ if (left_path)
+ ocfs2_free_path(left_path);
return ret;
}

static int ocfs2_try_to_merge_extent(struct inode *inode,
handle_t *handle,
- struct ocfs2_path *left_path,
+ struct ocfs2_path *path,
int split_index,
struct ocfs2_extent_rec *split_rec,
struct ocfs2_cached_dealloc_ctxt *dealloc,
@@ -2819,7 +3100,7 @@ static int ocfs2_try_to_merge_extent(struct inode *inode,

{
int ret = 0;
- struct ocfs2_extent_list *el = path_leaf_el(left_path);
+ struct ocfs2_extent_list *el = path_leaf_el(path);
struct ocfs2_extent_rec *rec = &el->l_recs[split_index];

BUG_ON(ctxt->c_contig_type == CONTIG_NONE);
@@ -2832,7 +3113,7 @@ static int ocfs2_try_to_merge_extent(struct inode *inode,
* extents - having more than one in a leaf is
* illegal.
*/
- ret = ocfs2_rotate_tree_left(inode, handle, left_path,
+ ret = ocfs2_rotate_tree_left(inode, handle, path,
dealloc);
if (ret) {
mlog_errno(ret);
@@ -2847,7 +3128,6 @@ static int ocfs2_try_to_merge_extent(struct inode *inode,
* Left-right contig implies this.
*/
BUG_ON(!ctxt->c_split_covers_rec);
- BUG_ON(split_index == 0);

/*
* Since the leftright insert always covers the entire
@@ -2858,9 +3138,14 @@ static int ocfs2_try_to_merge_extent(struct inode *inode,
* Since the adding of an empty extent shifts
* everything back to the right, there's no need to
* update split_index here.
+ *
+ * When the split_index is zero, we need to merge it to the
+ * prevoius extent block. It is more efficient and easier
+ * if we do merge_right first and merge_left later.
*/
- ret = ocfs2_merge_rec_left(inode, path_leaf_bh(left_path),
- handle, split_rec, el, split_index);
+ ret = ocfs2_merge_rec_right(inode, path,
+ handle, split_rec,
+ split_index);
if (ret) {
mlog_errno(ret);
goto out;
@@ -2871,32 +3156,30 @@ static int ocfs2_try_to_merge_extent(struct inode *inode,
*/
BUG_ON(!ocfs2_is_empty_extent(&el->l_recs[0]));

- /*
- * The left merge left us with an empty extent, remove
- * it.
- */
- ret = ocfs2_rotate_tree_left(inode, handle, left_path, dealloc);
+ /* The merge left us with an empty extent, remove it. */
+ ret = ocfs2_rotate_tree_left(inode, handle, path, dealloc);
if (ret) {
mlog_errno(ret);
goto out;
}
- split_index--;
+
rec = &el->l_recs[split_index];

/*
* Note that we don't pass split_rec here on purpose -
- * we've merged it into the left side.
+ * we've merged it into the rec already.
*/
- ret = ocfs2_merge_rec_right(inode, path_leaf_bh(left_path),
- handle, rec, el, split_index);
+ ret = ocfs2_merge_rec_left(inode, path,
+ handle, rec,
+ dealloc,
+ split_index);
+
if (ret) {
mlog_errno(ret);
goto out;
}

- BUG_ON(!ocfs2_is_empty_extent(&el->l_recs[0]));
-
- ret = ocfs2_rotate_tree_left(inode, handle, left_path,
+ ret = ocfs2_rotate_tree_left(inode, handle, path,
dealloc);
/*
* Error from this last rotate is not critical, so
@@ -2915,8 +3198,9 @@ static int ocfs2_try_to_merge_extent(struct inode *inode,
*/
if (ctxt->c_contig_type == CONTIG_RIGHT) {
ret = ocfs2_merge_rec_left(inode,
- path_leaf_bh(left_path),
- handle, split_rec, el,
+ path,
+ handle, split_rec,
+ dealloc,
split_index);
if (ret) {
mlog_errno(ret);
@@ -2924,8 +3208,8 @@ static int ocfs2_try_to_merge_extent(struct inode *inode,
}
} else {
ret = ocfs2_merge_rec_right(inode,
- path_leaf_bh(left_path),
- handle, split_rec, el,
+ path,
+ handle, split_rec,
split_index);
if (ret) {
mlog_errno(ret);
@@ -2938,7 +3222,7 @@ static int ocfs2_try_to_merge_extent(struct inode *inode,
* The merge may have left an empty extent in
* our leaf. Try to rotate it away.
*/
- ret = ocfs2_rotate_tree_left(inode, handle, left_path,
+ ret = ocfs2_rotate_tree_left(inode, handle, path,
dealloc);
if (ret)
mlog_errno(ret);
--
1.5.4.1

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