convert/source-fs.c

   1 /*
   2  * This program is free software; you can redistribute it and/or
   3  * modify it under the terms of the GNU General Public
   4  * License v2 as published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   9  * General Public License for more details.
  10  *
  11  * You should have received a copy of the GNU General Public
  12  * License along with this program; if not, write to the
  13  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  14  * Boston, MA 021110-1307, USA.
  15  */
  16
  17 #include "kerncompat.h"
  18 #include <unistd.h>
  19 #include "internal.h"
  20 #include "disk-io.h"
  21 #include "volumes.h"
  22 #include "convert/common.h"
  23 #include "convert/source-fs.h"
  24
  25 const struct simple_range btrfs_reserved_ranges[3] = {
  26         { 0,                         SZ_1M },
  27         { BTRFS_SB_MIRROR_OFFSET(1), SZ_64K },
  28         { BTRFS_SB_MIRROR_OFFSET(2), SZ_64K }
  29 };
  30
  31 dev_t decode_dev(u32 dev)
  32 {
  33         unsigned major = (dev & 0xfff00) >> 8;
  34         unsigned minor = (dev & 0xff) | ((dev >> 12) & 0xfff00);
  35
  36         return MKDEV(major, minor);
  37 }
  38
  39 int ext2_acl_count(size_t size)
  40 {
  41         ssize_t s;
  42
  43         size -= sizeof(ext2_acl_header);
  44         s = size - 4 * sizeof(ext2_acl_entry_short);
  45         if (s < 0) {
  46                 if (size % sizeof(ext2_acl_entry_short))
  47                         return -1;
  48                 return size / sizeof(ext2_acl_entry_short);
  49         } else {
  50                 if (s % sizeof(ext2_acl_entry))
  51                         return -1;
  52                 return s / sizeof(ext2_acl_entry) + 4;
  53         }
  54 }
  55
  56 static u64 intersect_with_reserved(u64 bytenr, u64 num_bytes)
  57 {
  58         int i;
  59
  60         for (i = 0; i < ARRAY_SIZE(btrfs_reserved_ranges); i++) {
  61                 const struct simple_range *range = &btrfs_reserved_ranges[i];
  62
  63                 if (bytenr < range_end(range) &&
  64                     bytenr + num_bytes >= range->start)
  65                         return range_end(range);
  66         }
  67         return 0;
  68 }
  69
  70 void init_convert_context(struct btrfs_convert_context *cctx)
  71 {
  72         memset(cctx, 0, sizeof(*cctx));
  73
  74         cache_tree_init(&cctx->used_space);
  75         cache_tree_init(&cctx->data_chunks);
  76         cache_tree_init(&cctx->free_space);
  77 }
  78
  79 void clean_convert_context(struct btrfs_convert_context *cctx)
  80 {
  81         free_extent_cache_tree(&cctx->used_space);
  82         free_extent_cache_tree(&cctx->data_chunks);
  83         free_extent_cache_tree(&cctx->free_space);
  84 }
  85
  86 int block_iterate_proc(u64 disk_block, u64 file_block,
  87                               struct blk_iterate_data *idata)
  88 {
  89         int ret = 0;
  90         u64 reserved_boundary;
  91         int do_barrier;
  92         struct btrfs_root *root = idata->root;
  93         struct btrfs_block_group_cache *cache;
  94         u32 sectorsize = root->fs_info->sectorsize;
  95         u64 bytenr = disk_block * sectorsize;
  96
  97         reserved_boundary = intersect_with_reserved(bytenr, sectorsize);
  98         do_barrier = reserved_boundary || disk_block >= idata->boundary;
  99         if ((idata->num_blocks > 0 && do_barrier) ||
 100             (file_block > idata->first_block + idata->num_blocks) ||
 101             (disk_block != idata->disk_block + idata->num_blocks)) {
 102                 if (idata->num_blocks > 0) {
 103                         ret = record_file_blocks(idata, idata->first_block,
 104                                                  idata->disk_block,
 105                                                  idata->num_blocks);
 106                         if (ret)
 107                                 goto fail;
 108                         idata->first_block += idata->num_blocks;
 109                         idata->num_blocks = 0;
 110                 }
 111                 if (file_block > idata->first_block) {
 112                         ret = record_file_blocks(idata, idata->first_block,
 113                                         0, file_block - idata->first_block);
 114                         if (ret)
 115                                 goto fail;
 116                 }
 117
 118                 if (reserved_boundary) {
 119                         bytenr = reserved_boundary;
 120                 } else {
 121                         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
 122                         BUG_ON(!cache);
 123                         bytenr = cache->key.objectid + cache->key.offset;
 124                 }
 125
 126                 idata->first_block = file_block;
 127                 idata->disk_block = disk_block;
 128                 idata->boundary = bytenr / sectorsize;
 129         }
 130         idata->num_blocks++;
 131 fail:
 132         return ret;
 133 }
 134
 135 void init_blk_iterate_data(struct blk_iterate_data *data,
 136                                   struct btrfs_trans_handle *trans,
 137                                   struct btrfs_root *root,
 138                                   struct btrfs_inode_item *inode,
 139                                   u64 objectid, int checksum)
 140 {
 141         struct btrfs_key key;
 142
 143         data->trans             = trans;
 144         data->root              = root;
 145         data->inode             = inode;
 146         data->objectid          = objectid;
 147         data->first_block       = 0;
 148         data->disk_block        = 0;
 149         data->num_blocks        = 0;
 150         data->boundary          = (u64)-1;
 151         data->checksum          = checksum;
 152         data->errcode           = 0;
 153
 154         key.objectid = CONV_IMAGE_SUBVOL_OBJECTID;
 155         key.type = BTRFS_ROOT_ITEM_KEY;
 156         key.offset = (u64)-1;
 157         data->convert_root = btrfs_read_fs_root(root->fs_info, &key);
 158         /* Impossible as we just opened it before */
 159         BUG_ON(!data->convert_root || IS_ERR(data->convert_root));
 160         data->convert_ino = BTRFS_FIRST_FREE_OBJECTID + 1;
 161 }
 162
 163 int convert_insert_dirent(struct btrfs_trans_handle *trans,
 164                                  struct btrfs_root *root,
 165                                  const char *name, size_t name_len,
 166                                  u64 dir, u64 objectid,
 167                                  u8 file_type, u64 index_cnt,
 168                                  struct btrfs_inode_item *inode)
 169 {
 170         int ret;
 171         u64 inode_size;
 172         struct btrfs_key location = {
 173                 .objectid = objectid,
 174                 .offset = 0,
 175                 .type = BTRFS_INODE_ITEM_KEY,
 176         };
 177
 178         ret = btrfs_insert_dir_item(trans, root, name, name_len,
 179                                     dir, &location, file_type, index_cnt);
 180         if (ret)
 181                 return ret;
 182         ret = btrfs_insert_inode_ref(trans, root, name, name_len,
 183                                      objectid, dir, index_cnt);
 184         if (ret)
 185                 return ret;
 186         inode_size = btrfs_stack_inode_size(inode) + name_len * 2;
 187         btrfs_set_stack_inode_size(inode, inode_size);
 188
 189         return 0;
 190 }
 191
 192 int read_disk_extent(struct btrfs_root *root, u64 bytenr,
 193                             u32 num_bytes, char *buffer)
 194 {
 195         int ret;
 196         struct btrfs_fs_devices *fs_devs = root->fs_info->fs_devices;
 197
 198         ret = pread(fs_devs->latest_bdev, buffer, num_bytes, bytenr);
 199         if (ret != num_bytes)
 200                 goto fail;
 201         ret = 0;
 202 fail:
 203         if (ret > 0)
 204                 ret = -1;
 205         return ret;
 206 }
 207
 208 /*
 209  * Record a file extent in original filesystem into btrfs one.
 210  * The special point is, old disk_block can point to a reserved range.
 211  * So here, we don't use disk_block directly but search convert_root
 212  * to get the real disk_bytenr.
 213  */
 214 int record_file_blocks(struct blk_iterate_data *data,
 215                               u64 file_block, u64 disk_block, u64 num_blocks)
 216 {
 217         int ret = 0;
 218         struct btrfs_root *root = data->root;
 219         struct btrfs_root *convert_root = data->convert_root;
 220         struct btrfs_path path;
 221         u32 sectorsize = root->fs_info->sectorsize;
 222         u64 file_pos = file_block * sectorsize;
 223         u64 old_disk_bytenr = disk_block * sectorsize;
 224         u64 num_bytes = num_blocks * sectorsize;
 225         u64 cur_off = old_disk_bytenr;
 226
 227         /* Hole, pass it to record_file_extent directly */
 228         if (old_disk_bytenr == 0)
 229                 return btrfs_record_file_extent(data->trans, root,
 230                                 data->objectid, data->inode, file_pos, 0,
 231                                 num_bytes);
 232
 233         btrfs_init_path(&path);
 234
 235         /*
 236          * Search real disk bytenr from convert root
 237          */
 238         while (cur_off < old_disk_bytenr + num_bytes) {
 239                 struct btrfs_key key;
 240                 struct btrfs_file_extent_item *fi;
 241                 struct extent_buffer *node;
 242                 int slot;
 243                 u64 extent_disk_bytenr;
 244                 u64 extent_num_bytes;
 245                 u64 real_disk_bytenr;
 246                 u64 cur_len;
 247
 248                 key.objectid = data->convert_ino;
 249                 key.type = BTRFS_EXTENT_DATA_KEY;
 250                 key.offset = cur_off;
 251
 252                 ret = btrfs_search_slot(NULL, convert_root, &key, &path, 0, 0);
 253                 if (ret < 0)
 254                         break;
 255                 if (ret > 0) {
 256                         ret = btrfs_previous_item(convert_root, &path,
 257                                                   data->convert_ino,
 258                                                   BTRFS_EXTENT_DATA_KEY);
 259                         if (ret < 0)
 260                                 break;
 261                         if (ret > 0) {
 262                                 ret = -ENOENT;
 263                                 break;
 264                         }
 265                 }
 266                 node = path.nodes[0];
 267                 slot = path.slots[0];
 268                 btrfs_item_key_to_cpu(node, &key, slot);
 269                 BUG_ON(key.type != BTRFS_EXTENT_DATA_KEY ||
 270                        key.objectid != data->convert_ino ||
 271                        key.offset > cur_off);
 272                 fi = btrfs_item_ptr(node, slot, struct btrfs_file_extent_item);
 273                 extent_disk_bytenr = btrfs_file_extent_disk_bytenr(node, fi);
 274                 extent_num_bytes = btrfs_file_extent_num_bytes(node, fi);
 275                 BUG_ON(cur_off - key.offset >= extent_num_bytes);
 276                 btrfs_release_path(&path);
 277
 278                 if (extent_disk_bytenr)
 279                         real_disk_bytenr = cur_off - key.offset +
 280                                            extent_disk_bytenr;
 281                 else
 282                         real_disk_bytenr = 0;
 283                 cur_len = min(key.offset + extent_num_bytes,
 284                               old_disk_bytenr + num_bytes) - cur_off;
 285                 ret = btrfs_record_file_extent(data->trans, data->root,
 286                                         data->objectid, data->inode, file_pos,
 287                                         real_disk_bytenr, cur_len);
 288                 if (ret < 0)
 289                         break;
 290                 cur_off += cur_len;
 291                 file_pos += cur_len;
 292
 293                 /*
 294                  * No need to care about csum
 295                  * As every byte of old fs image is calculated for csum, no
 296                  * need to waste CPU cycles now.
 297                  */
 298         }
 299         btrfs_release_path(&path);
 300         return ret;
 301 }
 302