Import btrfs_insert/del/lookup_extref() functions form kernel for the
incoming btrfs_add_link() and btrfs_unlink() functions.
As the base of incoming btrfs 'lost+found' recovery mechanism.
Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com>
---
ctree.h | 14 ++++
inode-item.c | 206 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 220 insertions(+)
diff --git a/ctree.h b/ctree.h
index 89036de..e185e7a 100644
--- a/ctree.h
+++ b/ctree.h
@@ -2389,6 +2389,20 @@ int btrfs_insert_inode(struct btrfs_trans_handle *trans,
struct btrfs_root
int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path,
struct btrfs_key *location, int mod);
+struct btrfs_inode_extref
+*btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
+ struct btrfs_path *path, struct btrfs_root *root,
+ u64 ino, u64 parent_ino, u64 index, const char *name,
+ int namelen, int ins_len);
+int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ const char *name, int name_len,
+ u64 inode_objectid, u64 ref_objectid,
+ u64 *index);
+int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ const char *name, int name_len,
+ u64 inode_objectid, u64 ref_objectid, u64 index);
/* file-item.c */
int btrfs_del_csums(struct btrfs_trans_handle *trans,
diff --git a/inode-item.c b/inode-item.c
index 8cc98c6..7337ac9 100644
--- a/inode-item.c
+++ b/inode-item.c
@@ -19,6 +19,7 @@
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
+#include "crc32c.h"
static int find_name_in_backref(struct btrfs_path *path, const char * name,
int name_len, struct btrfs_inode_ref **ref_ret)
@@ -145,3 +146,208 @@ int btrfs_insert_inode(struct btrfs_trans_handle *trans,
struct btrfs_root
sizeof(*inode_item));
return ret;
}
+
+static inline u64 btrfs_extref_hash(u64 parent_ino, const char *name,
+ int namelen)
+{
+ return (u64) btrfs_crc32c(parent_ino, name, namelen);
+}
+
+static int
+btrfs_find_name_in_ext_backref(struct btrfs_path *path,
+ u64 parent_ino, const char *name,
+ int namelen,
+ struct btrfs_inode_extref **extref_ret)
+{
+ struct extent_buffer *node;
+ struct btrfs_inode_extref *extref;
+ unsigned long ptr;
+ unsigned long name_ptr;
+ u32 item_size;
+ u32 cur_offset = 0;
+ int ref_name_len;
+ int slot;
+
+ node = path->nodes[0];
+ slot = path->slots[0];
+ item_size = btrfs_item_size_nr(node, slot);
+ ptr = btrfs_item_ptr_offset(node, slot);
+
+ /*
+ * Search all extended backrefs in this item. We're only
+ * looking through any collisions so most of the time this is
+ * just going to compare against one buffer. If all is well,
+ * we'll return success and the inode ref object.
+ */
+ while (cur_offset < item_size) {
+ extref = (struct btrfs_inode_extref *) (ptr + cur_offset);
+ name_ptr = (unsigned long)(&extref->name);
+ ref_name_len = btrfs_inode_extref_name_len(node, extref);
+
+ if (ref_name_len == namelen &&
+ btrfs_inode_extref_parent(node, extref) == parent_ino &&
+ (memcmp_extent_buffer(node, name, name_ptr,
+ namelen) == 0)) {
+ if (extref_ret)
+ *extref_ret = extref;
+ return 1;
+ }
+
+ cur_offset += ref_name_len + sizeof(*extref);
+ }
+ return 0;
+}
+
+struct btrfs_inode_extref
+*btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
+ struct btrfs_path *path, struct btrfs_root *root,
+ u64 ino, u64 parent_ino, u64 index, const char *name,
+ int namelen, int ins_len)
+{
+ struct btrfs_key key;
+ struct btrfs_inode_extref *extref;
+ int ret = 0;
+
+ key.objectid = ino;
+ key.type = BTRFS_INODE_EXTREF_KEY;
+ key.offset = btrfs_extref_hash(parent_ino, name, namelen);
+
+ ret = btrfs_search_slot(trans, root, &key, path, ins_len,
+ ins_len ? 1 : 0);
+ if (ret < 0)
+ return ERR_PTR(ret);
+ if (ret > 0)
+ return NULL;
+ if (!btrfs_find_name_in_ext_backref(path, parent_ino, name,
+ namelen, &extref))
+ return NULL;
+ return extref;
+}
+
+int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ const char *name, int name_len,
+ u64 inode_objectid, u64 ref_objectid,
+ u64 *index)
+{
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ struct btrfs_inode_extref *extref;
+ struct extent_buffer *leaf;
+ int ret;
+ int del_len = name_len + sizeof(*extref);
+ unsigned long ptr;
+ unsigned long item_start;
+ u32 item_size;
+
+ key.objectid = inode_objectid;
+ key.type = BTRFS_INODE_EXTREF_KEY;
+ key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+ if (ret > 0)
+ ret = -ENOENT;
+ if (ret < 0)
+ goto out;
+
+ /*
+ * Sanity check - did we find the right item for this name?
+ * This should always succeed so error here will make the FS
+ * readonly.
+ */
+ if (!btrfs_find_name_in_ext_backref(path, ref_objectid,
+ name, name_len, &extref)) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ leaf = path->nodes[0];
+ item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+ if (index)
+ *index = btrfs_inode_extref_index(leaf, extref);
+
+ if (del_len == item_size) {
+ /*
+ * Common case only one ref in the item, remove the
+ * whole item.
+ */
+ ret = btrfs_del_item(trans, root, path);
+ goto out;
+ }
+
+ ptr = (unsigned long)extref;
+ item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
+
+ memmove_extent_buffer(leaf, ptr, ptr + del_len,
+ item_size - (ptr + del_len - item_start));
+
+ btrfs_truncate_item(trans, root, path, item_size - del_len, 1);
+
+out:
+ btrfs_free_path(path);
+
+ return ret;
+}
+
+/*
+ * btrfs_insert_inode_extref() - Inserts an extended inode ref into a tree.
+ *
+ * The caller must have checked against BTRFS_LINK_MAX already.
+ */
+int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ const char *name, int name_len,
+ u64 inode_objectid, u64 ref_objectid, u64 index)
+{
+ struct btrfs_inode_extref *extref;
+ int ret;
+ int ins_len = name_len + sizeof(*extref);
+ unsigned long ptr;
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ struct extent_buffer *leaf;
+ struct btrfs_item *item;
+
+ key.objectid = inode_objectid;
+ key.type = BTRFS_INODE_EXTREF_KEY;
+ key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ ret = btrfs_insert_empty_item(trans, root, path, &key,
+ ins_len);
+ if (ret == -EEXIST) {
+ if (btrfs_find_name_in_ext_backref(path, ref_objectid,
+ name, name_len, NULL))
+ goto out;
+
+ btrfs_extend_item(trans, root, path, ins_len);
+ ret = 0;
+ }
+ if (ret < 0)
+ goto out;
+
+ leaf = path->nodes[0];
+ item = btrfs_item_nr(path->slots[0]);
+ ptr = (unsigned long)btrfs_item_ptr(leaf, path->slots[0], char);
+ ptr += btrfs_item_size(leaf, item) - ins_len;
+ extref = (struct btrfs_inode_extref *)ptr;
+
+ btrfs_set_inode_extref_name_len(path->nodes[0], extref, name_len);
+ btrfs_set_inode_extref_index(path->nodes[0], extref, index);
+ btrfs_set_inode_extref_parent(path->nodes[0], extref, ref_objectid);
+
+ ptr = (unsigned long)&extref->name;
+ write_extent_buffer(path->nodes[0], name, ptr, name_len);
+ btrfs_mark_buffer_dirty(path->nodes[0]);
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
--
2.1.3
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