btrfs: extended inode refs

This patch adds basic support for extended inode refs. This includes support
for link and unlink of the refs, which basically gets us support for rename
as well.

Inode creation does not need changing - extended refs are only added after
the ref array is full.

Signed-off-by: Mark Fasheh <mfasheh@suse.de>

1 files changed, 46 insertions, 7 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 399521ab61da..50dcd0fbae11 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -154,6 +154,13 @@ struct btrfs_ordered_sum;
  */
 #define BTRFS_NAME_LEN 255
 
+/*
+ * Theoretical limit is larger, but we keep this down to a sane
+ * value. That should limit greatly the possibility of collisions on
+ * inode ref items.
+ */
+#define BTRFS_LINK_MAX 65535U
+
 /* 32 bytes in various csum fields */
 #define BTRFS_CSUM_SIZE 32
 
@@ -489,6 +496,8 @@ struct btrfs_super_block {
  */
 #define BTRFS_FEATURE_INCOMPAT_BIG_METADATA     (1ULL << 5)
 
+#define BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF    (1ULL << 6)
+
 #define BTRFS_FEATURE_COMPAT_SUPP               0ULL
 #define BTRFS_FEATURE_COMPAT_RO_SUPP            0ULL
 #define BTRFS_FEATURE_INCOMPAT_SUPP                     \
@@ -496,7 +505,8 @@ struct btrfs_super_block {
          BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL |        \
          BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS |          \
          BTRFS_FEATURE_INCOMPAT_BIG_METADATA |          \
-         BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO)
+         BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO |          \
+         BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
 
 /*
  * A leaf is full of items. offset and size tell us where to find
@@ -643,6 +653,14 @@ struct btrfs_inode_ref {
         /* name goes here */
 } __attribute__ ((__packed__));
 
+struct btrfs_inode_extref {
+        __le64 parent_objectid;
+        __le64 index;
+        __le16 name_len;
+        __u8   name[0];
+        /* name goes here */
+} __attribute__ ((__packed__));
+
 struct btrfs_timespec {
         __le64 sec;
         __le32 nsec;
@@ -1601,6 +1619,7 @@ struct btrfs_ioctl_defrag_range_args {
  */
 #define BTRFS_INODE_ITEM_KEY            1
 #define BTRFS_INODE_REF_KEY             12
+#define BTRFS_INODE_EXTREF_KEY          13
 #define BTRFS_XATTR_ITEM_KEY            24
 #define BTRFS_ORPHAN_ITEM_KEY           48
 /* reserve 2-15 close to the inode for later flexibility */
@@ -1987,6 +2006,13 @@ BTRFS_SETGET_STACK_FUNCS(block_group_flags,
 BTRFS_SETGET_FUNCS(inode_ref_name_len, struct btrfs_inode_ref, name_len, 16);
 BTRFS_SETGET_FUNCS(inode_ref_index, struct btrfs_inode_ref, index, 64);
 
+/* struct btrfs_inode_extref */
+BTRFS_SETGET_FUNCS(inode_extref_parent, struct btrfs_inode_extref,
+                   parent_objectid, 64);
+BTRFS_SETGET_FUNCS(inode_extref_name_len, struct btrfs_inode_extref,
+                   name_len, 16);
+BTRFS_SETGET_FUNCS(inode_extref_index, struct btrfs_inode_extref, index, 64);
+
 /* struct btrfs_inode_item */
 BTRFS_SETGET_FUNCS(inode_generation, struct btrfs_inode_item, generation, 64);
 BTRFS_SETGET_FUNCS(inode_sequence, struct btrfs_inode_item, sequence, 64);
@@ -3184,12 +3210,12 @@ int btrfs_del_inode_ref(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_ref *
-btrfs_lookup_inode_ref(struct btrfs_trans_handle *trans,
-                        struct btrfs_root *root,
-                        struct btrfs_path *path,
-                        const char *name, int name_len,
-                        u64 inode_objectid, u64 ref_objectid, int mod);
+int btrfs_get_inode_ref_index(struct btrfs_trans_handle *trans,
+                              struct btrfs_root *root,
+                              struct btrfs_path *path,
+                              const char *name, int name_len,
+                              u64 inode_objectid, u64 ref_objectid, int mod,
+                              u64 *ret_index);
 int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
                              struct btrfs_root *root,
                              struct btrfs_path *path, u64 objectid);
@@ -3197,6 +3223,19 @@ 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_root *root,
+                          struct btrfs_path *path,
+                          const char *name, int name_len,
+                          u64 inode_objectid, u64 ref_objectid, int ins_len,
+                          int cow);
+
+int btrfs_find_name_in_ext_backref(struct btrfs_path *path,
+                                   u64 ref_objectid, const char *name,
+                                   int name_len,
+                                   struct btrfs_inode_extref **extref_ret);
+
 /* file-item.c */
 int btrfs_del_csums(struct btrfs_trans_handle *trans,
                     struct btrfs_root *root, u64 bytenr, u64 len);