ocfs2: Abstract ocfs2_extent_tree in b-tree operations.
In the old extent tree operation, we take the hypothesis that we
are using the ocfs2_extent_list in ocfs2_dinode as the tree root.
As xattr will also use ocfs2_extent_list to store large value
for a xattr entry, we refactor the tree operation so that xattr
can use it directly.
The refactoring includes 4 steps:
1. Abstract set/get of last_eb_blk and update_clusters since they may
be stored in different location for dinode and xattr.
2. Add a new structure named ocfs2_extent_tree to indicate the
extent tree the operation will work on.
3. Remove all the use of fe_bh and di, use root_bh and root_el in
extent tree instead. So now all the fe_bh is replaced with
et->root_bh, el with root_el accordingly.
4. Make ocfs2_lock_allocators generic. Now it is limited to be only used
in file extend allocation. But the whole function is useful when we want
to store large EAs.
Note: This patch doesn't touch ocfs2_commit_truncate() since it is not used
for anything other than truncate inode data btrees.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index 2a817bc..b642c82 100644
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -1894,3 +1894,85 @@
(unsigned long long)fe->id2.i_chain.cl_recs[i].c_blkno);
}
}
+
+/*
+ * For a given allocation, determine which allocators will need to be
+ * accessed, and lock them, reserving the appropriate number of bits.
+ *
+ * Sparse file systems call this from ocfs2_write_begin_nolock()
+ * and ocfs2_allocate_unwritten_extents().
+ *
+ * File systems which don't support holes call this from
+ * ocfs2_extend_allocation().
+ */
+int ocfs2_lock_allocators(struct inode *inode, struct buffer_head *root_bh,
+ struct ocfs2_extent_list *root_el,
+ u32 clusters_to_add, u32 extents_to_split,
+ struct ocfs2_alloc_context **data_ac,
+ struct ocfs2_alloc_context **meta_ac)
+{
+ int ret = 0, num_free_extents;
+ unsigned int max_recs_needed = clusters_to_add + 2 * extents_to_split;
+ struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+ *meta_ac = NULL;
+ if (data_ac)
+ *data_ac = NULL;
+
+ BUG_ON(clusters_to_add != 0 && data_ac == NULL);
+
+ num_free_extents = ocfs2_num_free_extents(osb, inode, root_bh,
+ OCFS2_DINODE_EXTENT);
+ if (num_free_extents < 0) {
+ ret = num_free_extents;
+ mlog_errno(ret);
+ goto out;
+ }
+
+ /*
+ * Sparse allocation file systems need to be more conservative
+ * with reserving room for expansion - the actual allocation
+ * happens while we've got a journal handle open so re-taking
+ * a cluster lock (because we ran out of room for another
+ * extent) will violate ordering rules.
+ *
+ * Most of the time we'll only be seeing this 1 cluster at a time
+ * anyway.
+ *
+ * Always lock for any unwritten extents - we might want to
+ * add blocks during a split.
+ */
+ if (!num_free_extents ||
+ (ocfs2_sparse_alloc(osb) && num_free_extents < max_recs_needed)) {
+ ret = ocfs2_reserve_new_metadata(osb, root_el, meta_ac);
+ if (ret < 0) {
+ if (ret != -ENOSPC)
+ mlog_errno(ret);
+ goto out;
+ }
+ }
+
+ if (clusters_to_add == 0)
+ goto out;
+
+ ret = ocfs2_reserve_clusters(osb, clusters_to_add, data_ac);
+ if (ret < 0) {
+ if (ret != -ENOSPC)
+ mlog_errno(ret);
+ goto out;
+ }
+
+out:
+ if (ret) {
+ if (*meta_ac) {
+ ocfs2_free_alloc_context(*meta_ac);
+ *meta_ac = NULL;
+ }
+
+ /*
+ * We cannot have an error and a non null *data_ac.
+ */
+ }
+
+ return ret;
+}