1 files changed, 274 insertions, 11 deletions

diff --git a/fs/btrfs/inode-item.c b/fs/btrfs/inode-item.c
index a13cf1a96c73..48b8fda93132 100644
--- a/fs/btrfs/inode-item.c
+++ b/fs/btrfs/inode-item.c
@@ -18,6 +18,7 @@
 
 #include "ctree.h"
 #include "disk-io.h"
+#include "hash.h"
 #include "transaction.h"
 #include "print-tree.h"
 
@@ -50,18 +51,57 @@ static int find_name_in_backref(struct btrfs_path *path, const char *name,
         return 0;
 }
 
-struct btrfs_inode_ref *
+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)
+{
+        struct extent_buffer *leaf;
+        struct btrfs_inode_extref *extref;
+        unsigned long ptr;
+        unsigned long name_ptr;
+        u32 item_size;
+        u32 cur_offset = 0;
+        int ref_name_len;
+
+        leaf = path->nodes[0];
+        item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+        ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
+
+        /*
+         * 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(leaf, extref);
+
+                if (ref_name_len == name_len &&
+                    btrfs_inode_extref_parent(leaf, extref) == ref_objectid &&
+                    (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)) {
+                        if (extref_ret)
+                                *extref_ret = extref;
+                        return 1;
+                }
+
+                cur_offset += ref_name_len + sizeof(*extref);
+        }
+        return 0;
+}
+
+static 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)
+                       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 ret;
         struct btrfs_key key;
         struct btrfs_inode_ref *ref;
-        int ins_len = mod < 0 ? -1 : 0;
-        int cow = mod != 0;
-        int ret;
 
         key.objectid = inode_objectid;
         key.type = BTRFS_INODE_REF_KEY;
@@ -77,13 +117,150 @@ btrfs_lookup_inode_ref(struct btrfs_trans_handle *trans,
         return ref;
 }
 
-int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
+/* Returns NULL if no extref found */
+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 ret;
+        struct btrfs_key key;
+        struct btrfs_inode_extref *extref;
+
+        key.objectid = inode_objectid;
+        key.type = BTRFS_INODE_EXTREF_KEY;
+        key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
+
+        ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
+        if (ret < 0)
+                return ERR_PTR(ret);
+        if (ret > 0)
+                return NULL;
+        if (!btrfs_find_name_in_ext_backref(path, ref_objectid, name, name_len, &extref))
+                return NULL;
+        return extref;
+}
+
+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)
+{
+        struct btrfs_inode_ref *ref;
+        struct btrfs_inode_extref *extref;
+        int ins_len = mod < 0 ? -1 : 0;
+        int cow = mod != 0;
+
+        ref = btrfs_lookup_inode_ref(trans, root, path, name, name_len,
+                                     inode_objectid, ref_objectid, ins_len,
+                                     cow);
+        if (IS_ERR(ref))
+                return PTR_ERR(ref);
+
+        if (ref != NULL) {
+                *ret_index = btrfs_inode_ref_index(path->nodes[0], ref);
+                return 0;
+        }
+
+        btrfs_release_path(path);
+
+        extref = btrfs_lookup_inode_extref(trans, root, path, name,
+                                           name_len, inode_objectid,
+                                           ref_objectid, ins_len, cow);
+        if (IS_ERR(extref))
+                return PTR_ERR(extref);
+
+        if (extref) {
+                *ret_index = btrfs_inode_extref_index(path->nodes[0], extref);
+                return 0;
+        }
+
+        return -ENOENT;
+}
+
+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;
+        btrfs_set_key_type(&key, BTRFS_INODE_EXTREF_KEY);
+        key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
+
+        path = btrfs_alloc_path();
+        if (!path)
+                return -ENOMEM;
+
+        path->leave_spinning = 1;
+
+        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)) {
+                btrfs_std_error(root->fs_info, -ENOENT);
+                ret = -EROFS;
+                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;
+}
+
+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_path *path;
+        struct btrfs_key key;
         struct btrfs_inode_ref *ref;
         struct extent_buffer *leaf;
         unsigned long ptr;
@@ -91,6 +268,7 @@ int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
         u32 item_size;
         u32 sub_item_len;
         int ret;
+        int search_ext_refs = 0;
         int del_len = name_len + sizeof(*ref);
 
         key.objectid = inode_objectid;
@@ -106,12 +284,14 @@ int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
         if (ret > 0) {
                 ret = -ENOENT;
+                search_ext_refs = 1;
                 goto out;
         } else if (ret < 0) {
                 goto out;
         }
         if (!find_name_in_backref(path, name, name_len, &ref)) {
                 ret = -ENOENT;
+                search_ext_refs = 1;
                 goto out;
         }
         leaf = path->nodes[0];
@@ -129,8 +309,78 @@ int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
         item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
         memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
                               item_size - (ptr + sub_item_len - item_start));
-        btrfs_truncate_item(trans, root, path,
-                                  item_size - sub_item_len, 1);
+        btrfs_truncate_item(trans, root, path, item_size - sub_item_len, 1);
+out:
+        btrfs_free_path(path);
+
+        if (search_ext_refs) {
+                /*
+                 * No refs were found, or we could not find the
+                 * name in our ref array. Find and remove the extended
+                 * inode ref then.
+                 */
+                return btrfs_del_inode_extref(trans, root, name, name_len,
+                                              inode_objectid, ref_objectid, index);
+        }
+
+        return ret;
+}
+
+/*
+ * btrfs_insert_inode_extref() - Inserts an extended inode ref into a tree.
+ *
+ * The caller must have checked against BTRFS_LINK_MAX already.
+ */
+static 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;
+
+        path->leave_spinning = 1;
+        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(leaf, 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;
@@ -191,6 +441,19 @@ int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
 
 out:
         btrfs_free_path(path);
+
+        if (ret == -EMLINK) {
+                struct btrfs_super_block *disk_super = root->fs_info->super_copy;
+                /* We ran out of space in the ref array. Need to
+                 * add an extended ref. */
+                if (btrfs_super_incompat_flags(disk_super)
+                    & BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
+                        ret = btrfs_insert_inode_extref(trans, root, name,
+                                                        name_len,
+                                                        inode_objectid,
+                                                        ref_objectid, index);
+        }
+
         return ret;
 }