fs/btrfs/dir-item.c

   1 #include <linux/module.h>
   2 #include "ctree.h"
   3 #include "disk-io.h"
   4 #include "hash.h"
   5 #include "transaction.h"
   6
   7 static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle
   8                                                    *trans,
   9                                                    struct btrfs_root *root,
  10                                                    struct btrfs_path *path,
  11                                                    struct btrfs_key *cpu_key,
  12                                                    u32 data_size,
  13                                                    const char *name,
  14                                                    int name_len)
  15 {
  16         int ret;
  17         char *ptr;
  18         struct btrfs_item *item;
  19         struct btrfs_leaf *leaf;
  20
  21         ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
  22         if (ret == -EEXIST) {
  23                 struct btrfs_dir_item *di;
  24                 di = btrfs_match_dir_item_name(root, path, name, name_len);
  25                 if (di)
  26                         return ERR_PTR(-EEXIST);
  27                 ret = btrfs_extend_item(trans, root, path, data_size);
  28                 WARN_ON(ret > 0);
  29                 if (ret)
  30                         return ERR_PTR(ret);
  31         }
  32         WARN_ON(ret > 0);
  33         leaf = btrfs_buffer_leaf(path->nodes[0]);
  34         item = leaf->items + path->slots[0];
  35         ptr = btrfs_item_ptr(leaf, path->slots[0], char);
  36         BUG_ON(data_size > btrfs_item_size(item));
  37         ptr += btrfs_item_size(item) - data_size;
  38         return (struct btrfs_dir_item *)ptr;
  39 }
  40
  41 int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
  42                           *root, const char *name, int name_len, u64 dir,
  43                           struct btrfs_key *location, u8 type)
  44 {
  45         int ret = 0;
  46         int ret2 = 0;
  47         struct btrfs_path *path;
  48         struct btrfs_dir_item *dir_item;
  49         char *name_ptr;
  50         struct btrfs_key key;
  51         u32 data_size;
  52
  53         key.objectid = dir;
  54         key.flags = 0;
  55         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
  56         ret = btrfs_name_hash(name, name_len, &key.offset);
  57         BUG_ON(ret);
  58         path = btrfs_alloc_path();
  59         btrfs_init_path(path);
  60         data_size = sizeof(*dir_item) + name_len;
  61         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
  62                                         name, name_len);
  63         if (IS_ERR(dir_item)) {
  64                 ret = PTR_ERR(dir_item);
  65                 if (ret == -EEXIST)
  66                         goto second_insert;
  67                 goto out;
  68         }
  69
  70         btrfs_cpu_key_to_disk(&dir_item->location, location);
  71         btrfs_set_dir_type(dir_item, type);
  72         btrfs_set_dir_flags(dir_item, 0);
  73         btrfs_set_dir_name_len(dir_item, name_len);
  74         name_ptr = (char *)(dir_item + 1);
  75
  76         btrfs_memcpy(root, path->nodes[0]->b_data, name_ptr, name, name_len);
  77         btrfs_mark_buffer_dirty(path->nodes[0]);
  78
  79 second_insert:
  80         /* FIXME, use some real flag for selecting the extra index */
  81         if (root == root->fs_info->tree_root) {
  82                 ret = 0;
  83                 goto out;
  84         }
  85         btrfs_release_path(root, path);
  86
  87         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
  88         key.offset = location->objectid;
  89         dir_item = insert_with_overflow(trans, root, path, &key, data_size,
  90                                         name, name_len);
  91         if (IS_ERR(dir_item)) {
  92                 ret2 = PTR_ERR(dir_item);
  93                 goto out;
  94         }
  95         btrfs_cpu_key_to_disk(&dir_item->location, location);
  96         btrfs_set_dir_type(dir_item, type);
  97         btrfs_set_dir_flags(dir_item, 0);
  98         btrfs_set_dir_name_len(dir_item, name_len);
  99         name_ptr = (char *)(dir_item + 1);
 100         btrfs_memcpy(root, path->nodes[0]->b_data, name_ptr, name, name_len);
 101         btrfs_mark_buffer_dirty(path->nodes[0]);
 102 out:
 103         btrfs_free_path(path);
 104         if (ret)
 105                 return ret;
 106         if (ret2)
 107                 return ret2;
 108         return 0;
 109 }
 110
 111 struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
 112                                              struct btrfs_root *root,
 113                                              struct btrfs_path *path, u64 dir,
 114                                              const char *name, int name_len,
 115                                              int mod)
 116 {
 117         int ret;
 118         struct btrfs_key key;
 119         int ins_len = mod < 0 ? -1 : 0;
 120         int cow = mod != 0;
 121         struct btrfs_disk_key *found_key;
 122         struct btrfs_leaf *leaf;
 123
 124         key.objectid = dir;
 125         key.flags = 0;
 126         btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
 127         ret = btrfs_name_hash(name, name_len, &key.offset);
 128         BUG_ON(ret);
 129         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 130         if (ret < 0)
 131                 return ERR_PTR(ret);
 132         if (ret > 0) {
 133                 if (path->slots[0] == 0)
 134                         return NULL;
 135                 path->slots[0]--;
 136         }
 137         leaf = btrfs_buffer_leaf(path->nodes[0]);
 138         found_key = &leaf->items[path->slots[0]].key;
 139
 140         if (btrfs_disk_key_objectid(found_key) != dir ||
 141             btrfs_disk_key_type(found_key) != BTRFS_DIR_ITEM_KEY ||
 142             btrfs_disk_key_offset(found_key) != key.offset)
 143                 return NULL;
 144
 145         return btrfs_match_dir_item_name(root, path, name, name_len);
 146 }
 147
 148 struct btrfs_dir_item *
 149 btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
 150                             struct btrfs_root *root,
 151                             struct btrfs_path *path, u64 dir,
 152                             u64 objectid, const char *name, int name_len,
 153                             int mod)
 154 {
 155         int ret;
 156         struct btrfs_key key;
 157         int ins_len = mod < 0 ? -1 : 0;
 158         int cow = mod != 0;
 159
 160         key.objectid = dir;
 161         key.flags = 0;
 162         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
 163         key.offset = objectid;
 164
 165         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
 166         if (ret < 0)
 167                 return ERR_PTR(ret);
 168         if (ret > 0)
 169                 return ERR_PTR(-ENOENT);
 170         return btrfs_match_dir_item_name(root, path, name, name_len);
 171 }
 172
 173 struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
 174                               struct btrfs_path *path,
 175                               const char *name, int name_len)
 176 {
 177         struct btrfs_dir_item *dir_item;
 178         char *name_ptr;
 179         u32 total_len;
 180         u32 cur = 0;
 181         u32 this_len;
 182         struct btrfs_leaf *leaf;
 183
 184         leaf = btrfs_buffer_leaf(path->nodes[0]);
 185         dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
 186         total_len = btrfs_item_size(leaf->items + path->slots[0]);
 187         while(cur < total_len) {
 188                 this_len = sizeof(*dir_item) + btrfs_dir_name_len(dir_item);
 189                 name_ptr = (char *)(dir_item + 1);
 190
 191                 if (btrfs_dir_name_len(dir_item) == name_len &&
 192                     memcmp(name_ptr, name, name_len) == 0)
 193                         return dir_item;
 194
 195                 cur += this_len;
 196                 dir_item = (struct btrfs_dir_item *)((char *)dir_item +
 197                                                      this_len);
 198         }
 199         return NULL;
 200 }
 201
 202 int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
 203                               struct btrfs_root *root,
 204                               struct btrfs_path *path,
 205                               struct btrfs_dir_item *di)
 206 {
 207
 208         struct btrfs_leaf *leaf;
 209         u32 sub_item_len;
 210         u32 item_len;
 211         int ret;
 212
 213         leaf = btrfs_buffer_leaf(path->nodes[0]);
 214         sub_item_len = sizeof(*di) + btrfs_dir_name_len(di);
 215         item_len = btrfs_item_size(leaf->items + path->slots[0]);
 216         if (sub_item_len == btrfs_item_size(leaf->items + path->slots[0])) {
 217                 ret = btrfs_del_item(trans, root, path);
 218                 BUG_ON(ret);
 219         } else {
 220                 char *ptr = (char *)di;
 221                 char *start = btrfs_item_ptr(leaf, path->slots[0], char);
 222                 btrfs_memmove(root, leaf, ptr, ptr + sub_item_len,
 223                         item_len - (ptr + sub_item_len - start));
 224                 ret = btrfs_truncate_item(trans, root, path,
 225                                           item_len - sub_item_len);
 226                 BUG_ON(ret);
 227         }
 228         return 0;
 229 }
 230