This is a prepare work for the following extent map selftest, which
runs tests against em merge logic.
Signed-off-by: Liu Bo <bo.li....@oracle.com>
---
fs/btrfs/ctree.h | 2 ++
fs/btrfs/inode.c | 101 ++++++++++++++++++++++++++++++-------------------------
2 files changed, 58 insertions(+), 45 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index b2e09fe..328f40f 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3148,6 +3148,8 @@ struct btrfs_delalloc_work
*btrfs_alloc_delalloc_work(struct inode *inode,
int delay_iput);
void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work);
+int btrfs_add_extent_mapping(struct extent_map_tree *em_tree,
+ struct extent_map **em_in, u64 start, u64 len);
struct extent_map *btrfs_get_extent_fiemap(struct btrfs_inode *inode,
struct page *page, size_t pg_offset, u64 start,
u64 len, int create);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index e1a7f3c..527df6f 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6911,6 +6911,61 @@ static noinline int uncompress_inline(struct btrfs_path
*path,
return ret;
}
+int btrfs_add_extent_mapping(struct extent_map_tree *em_tree,
+ struct extent_map **em_in, u64 start, u64 len)
+{
+ int ret;
+ struct extent_map *em = *em_in;
+
+ ret = add_extent_mapping(em_tree, em, 0);
+ /* it is possible that someone inserted the extent into the tree
+ * while we had the lock dropped. It is also possible that
+ * an overlapping map exists in the tree
+ */
+ if (ret == -EEXIST) {
+ struct extent_map *existing;
+
+ ret = 0;
+
+ existing = search_extent_mapping(em_tree, start, len);
+
+ /*
+ * existing will always be non-NULL, since there must be
+ * extent causing the -EEXIST.
+ */
+ if (existing->start == em->start &&
+ extent_map_end(existing) >= extent_map_end(em) &&
+ em->block_start == existing->block_start) {
+ /*
+ * The existing extent map already encompasses the
+ * entire extent map we tried to add.
+ */
+ free_extent_map(em);
+ *em_in = existing;
+ ret = 0;
+ } else if (start >= extent_map_end(existing) ||
+ start <= existing->start) {
+ /*
+ * The existing extent map is the one nearest to
+ * the [start, start + len) range which overlaps
+ */
+ ret = merge_extent_mapping(em_tree, existing,
+ em, start);
+ free_extent_map(existing);
+ if (ret) {
+ free_extent_map(em);
+ *em_in = NULL;
+ }
+ } else {
+ free_extent_map(em);
+ *em_in = existing;
+ ret = 0;
+ }
+ }
+ ASSERT(ret == 0 || ret == -EEXIST);
+ return ret;
+}
+
/*
* a bit scary, this does extent mapping from logical file offset to the disk.
* the ugly parts come from merging extents from the disk with the in-ram
@@ -7147,51 +7202,7 @@ struct extent_map *btrfs_get_extent(struct btrfs_inode
*inode,
err = 0;
write_lock(&em_tree->lock);
- ret = add_extent_mapping(em_tree, em, 0);
- /* it is possible that someone inserted the extent into the tree
- * while we had the lock dropped. It is also possible that
- * an overlapping map exists in the tree
- */
- if (ret == -EEXIST) {
- struct extent_map *existing;
-
- ret = 0;
-
- existing = search_extent_mapping(em_tree, start, len);
- /*
- * existing will always be non-NULL, since there must be
- * extent causing the -EEXIST.
- */
- if (existing->start == em->start &&
- extent_map_end(existing) >= extent_map_end(em) &&
- em->block_start == existing->block_start) {
- /*
- * The existing extent map already encompasses the
- * entire extent map we tried to add.
- */
- free_extent_map(em);
- em = existing;
- err = 0;
-
- } else if (start >= extent_map_end(existing) ||
- start <= existing->start) {
- /*
- * The existing extent map is the one nearest to
- * the [start, start + len) range which overlaps
- */
- err = merge_extent_mapping(em_tree, existing,
- em, start);
- free_extent_map(existing);
- if (err) {
- free_extent_map(em);
- em = NULL;
- }
- } else {
- free_extent_map(em);
- em = existing;
- err = 0;
- }
- }
+ err = btrfs_add_extent_mapping(em_tree, &em, start, len);
write_unlock(&em_tree->lock);
out:
--
2.9.4
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