fs/btrfs/file-item.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/bio.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/highmem.h>
  22 #include "ctree.h"
  23 #include "disk-io.h"
  24 #include "transaction.h"
  25 #include "print-tree.h"
  26
  27 #define MAX_CSUM_ITEMS(r) ((((BTRFS_LEAF_DATA_SIZE(r) - \
  28                                sizeof(struct btrfs_item) * 2) / \
  29                                BTRFS_CRC32_SIZE) - 1))
  30 int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
  31                                struct btrfs_root *root,
  32                                u64 objectid, u64 pos,
  33                                u64 offset, u64 disk_num_bytes,
  34                                u64 num_bytes)
  35 {
  36         int ret = 0;
  37         struct btrfs_file_extent_item *item;
  38         struct btrfs_key file_key;
  39         struct btrfs_path *path;
  40         struct extent_buffer *leaf;
  41
  42         path = btrfs_alloc_path();
  43         BUG_ON(!path);
  44         file_key.objectid = objectid;
  45         file_key.offset = pos;
  46         btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
  47
  48         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
  49                                       sizeof(*item));
  50         if (ret < 0)
  51                 goto out;
  52         BUG_ON(ret);
  53         leaf = path->nodes[0];
  54         item = btrfs_item_ptr(leaf, path->slots[0],
  55                               struct btrfs_file_extent_item);
  56         btrfs_set_file_extent_disk_bytenr(leaf, item, offset);
  57         btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
  58         btrfs_set_file_extent_offset(leaf, item, 0);
  59         btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
  60         btrfs_set_file_extent_generation(leaf, item, trans->transid);
  61         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
  62         btrfs_mark_buffer_dirty(leaf);
  63 out:
  64         btrfs_free_path(path);
  65         return ret;
  66 }
  67
  68 struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
  69                                           struct btrfs_root *root,
  70                                           struct btrfs_path *path,
  71                                           u64 objectid, u64 offset,
  72                                           int cow)
  73 {
  74         int ret;
  75         struct btrfs_key file_key;
  76         struct btrfs_key found_key;
  77         struct btrfs_csum_item *item;
  78         struct extent_buffer *leaf;
  79         u64 csum_offset = 0;
  80         int csums_in_item;
  81
  82         file_key.objectid = objectid;
  83         file_key.offset = offset;
  84         btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
  85         ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
  86         if (ret < 0)
  87                 goto fail;
  88         leaf = path->nodes[0];
  89         if (ret > 0) {
  90                 ret = 1;
  91                 if (path->slots[0] == 0)
  92                         goto fail;
  93                 path->slots[0]--;
  94                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
  95                 if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
  96                     found_key.objectid != objectid) {
  97                         goto fail;
  98                 }
  99                 csum_offset = (offset - found_key.offset) >>
 100                                 root->fs_info->sb->s_blocksize_bits;
 101                 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]);
 102                 csums_in_item /= BTRFS_CRC32_SIZE;
 103
 104                 if (csum_offset >= csums_in_item) {
 105                         ret = -EFBIG;
 106                         goto fail;
 107                 }
 108         }
 109         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 110         item = (struct btrfs_csum_item *)((unsigned char *)item +
 111                                           csum_offset * BTRFS_CRC32_SIZE);
 112         return item;
 113 fail:
 114         if (ret > 0)
 115                 ret = -ENOENT;
 116         return ERR_PTR(ret);
 117 }
 118
 119
 120 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
 121                              struct btrfs_root *root,
 122                              struct btrfs_path *path, u64 objectid,
 123                              u64 offset, int mod)
 124 {
 125         int ret;
 126         struct btrfs_key file_key;
 127         int ins_len = mod < 0 ? -1 : 0;
 128         int cow = mod != 0;
 129
 130         file_key.objectid = objectid;
 131         file_key.offset = offset;
 132         btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
 133         ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
 134         return ret;
 135 }
 136
 137 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
 138                            struct btrfs_root *root, struct inode *inode,
 139                            struct bio *bio)
 140 {
 141         u64 objectid = inode->i_ino;
 142         u64 offset;
 143         int ret;
 144         struct btrfs_key file_key;
 145         struct btrfs_key found_key;
 146         u64 next_offset;
 147         int found_next;
 148         struct btrfs_path *path;
 149         struct btrfs_csum_item *item;
 150         struct btrfs_csum_item *item_end;
 151         struct extent_buffer *leaf = NULL;
 152         u64 csum_offset;
 153         u32 csum_result;
 154         u32 nritems;
 155         u32 ins_size;
 156         int bio_index = 0;
 157         struct bio_vec *bvec = bio->bi_io_vec;
 158         char *data;
 159
 160         path = btrfs_alloc_path();
 161         BUG_ON(!path);
 162 again:
 163         next_offset = (u64)-1;
 164         found_next = 0;
 165         offset = page_offset(bvec->bv_page) + bvec->bv_offset;
 166         file_key.objectid = objectid;
 167         file_key.offset = offset;
 168         btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
 169
 170         item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
 171         if (!IS_ERR(item)) {
 172                 leaf = path->nodes[0];
 173                 goto found;
 174         }
 175         ret = PTR_ERR(item);
 176         if (ret == -EFBIG) {
 177                 u32 item_size;
 178                 /* we found one, but it isn't big enough yet */
 179                 leaf = path->nodes[0];
 180                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 181                 if ((item_size / BTRFS_CRC32_SIZE) >= MAX_CSUM_ITEMS(root)) {
 182                         /* already at max size, make a new one */
 183                         goto insert;
 184                 }
 185         } else {
 186                 int slot = path->slots[0] + 1;
 187                 /* we didn't find a csum item, insert one */
 188                 nritems = btrfs_header_nritems(path->nodes[0]);
 189                 if (path->slots[0] >= nritems - 1) {
 190                         ret = btrfs_next_leaf(root, path);
 191                         if (ret == 1)
 192                                 found_next = 1;
 193                         if (ret != 0)
 194                                 goto insert;
 195                         slot = 0;
 196                 }
 197                 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot);
 198                 if (found_key.objectid != objectid ||
 199                     found_key.type != BTRFS_CSUM_ITEM_KEY) {
 200                         found_next = 1;
 201                         goto insert;
 202                 }
 203                 next_offset = found_key.offset;
 204                 found_next = 1;
 205                 goto insert;
 206         }
 207
 208         /*
 209          * at this point, we know the tree has an item, but it isn't big
 210          * enough yet to put our csum in.  Grow it
 211          */
 212         btrfs_release_path(root, path);
 213         ret = btrfs_search_slot(trans, root, &file_key, path,
 214                                 BTRFS_CRC32_SIZE, 1);
 215         if (ret < 0)
 216                 goto fail;
 217         if (ret == 0) {
 218                 BUG();
 219         }
 220         if (path->slots[0] == 0) {
 221                 goto insert;
 222         }
 223         path->slots[0]--;
 224         leaf = path->nodes[0];
 225         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 226         csum_offset = (offset - found_key.offset) >>
 227                         root->fs_info->sb->s_blocksize_bits;
 228         if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
 229             found_key.objectid != objectid ||
 230             csum_offset >= MAX_CSUM_ITEMS(root)) {
 231                 goto insert;
 232         }
 233         if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) /
 234             BTRFS_CRC32_SIZE) {
 235                 u32 diff = (csum_offset + 1) * BTRFS_CRC32_SIZE;
 236                 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]);
 237                 if (diff != BTRFS_CRC32_SIZE)
 238                         goto insert;
 239                 ret = btrfs_extend_item(trans, root, path, diff);
 240                 BUG_ON(ret);
 241                 goto csum;
 242         }
 243
 244 insert:
 245         btrfs_release_path(root, path);
 246         csum_offset = 0;
 247         if (found_next) {
 248                 u64 tmp = min((u64)i_size_read(inode), next_offset);
 249                 tmp -= offset & ~((u64)root->sectorsize -1);
 250                 tmp >>= root->fs_info->sb->s_blocksize_bits;
 251                 tmp = max((u64)1, tmp);
 252                 tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root));
 253                 ins_size = BTRFS_CRC32_SIZE * tmp;
 254         } else {
 255                 ins_size = BTRFS_CRC32_SIZE;
 256         }
 257         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 258                                       ins_size);
 259         if (ret < 0)
 260                 goto fail;
 261         if (ret != 0) {
 262                 WARN_ON(1);
 263                 goto fail;
 264         }
 265 csum:
 266         leaf = path->nodes[0];
 267         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 268         ret = 0;
 269         item = (struct btrfs_csum_item *)((unsigned char *)item +
 270                                           csum_offset * BTRFS_CRC32_SIZE);
 271 found:
 272         item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
 273         item_end = (struct btrfs_csum_item *)((unsigned char *)item_end +
 274                                       btrfs_item_size_nr(leaf, path->slots[0]));
 275 next_bvec:
 276         data = kmap_atomic(bvec->bv_page, KM_IRQ0);
 277         csum_result = ~(u32)0;
 278         csum_result = btrfs_csum_data(root, data + bvec->bv_offset,
 279                                       csum_result, bvec->bv_len);
 280         kunmap_atomic(data, KM_IRQ0);
 281         btrfs_csum_final(csum_result, (char *)&csum_result);
 282         if (csum_result == 0) {
 283                 printk("csum result is 0 for inode %lu offset %Lu\n", inode->i_ino, offset);
 284         }
 285
 286         write_extent_buffer(leaf, &csum_result, (unsigned long)item,
 287                             BTRFS_CRC32_SIZE);
 288         bio_index++;
 289         bvec++;
 290         if (bio_index < bio->bi_vcnt) {
 291                 item = (struct btrfs_csum_item *)((char *)item + BTRFS_CRC32_SIZE);
 292                 if (item < item_end)
 293                         goto next_bvec;
 294         }
 295         btrfs_mark_buffer_dirty(path->nodes[0]);
 296         if (bio_index < bio->bi_vcnt) {
 297                 btrfs_release_path(root, path);
 298                 goto again;
 299         }
 300 fail:
 301         btrfs_free_path(path);
 302         return ret;
 303 }
 304
 305 int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
 306                         struct btrfs_root *root, struct btrfs_path *path,
 307                         u64 isize)
 308 {
 309         struct btrfs_key key;
 310         struct extent_buffer *leaf = path->nodes[0];
 311         int slot = path->slots[0];
 312         int ret;
 313         u32 new_item_size;
 314         u64 new_item_span;
 315         u64 blocks;
 316
 317         btrfs_item_key_to_cpu(leaf, &key, slot);
 318         if (isize <= key.offset)
 319                 return 0;
 320         new_item_span = isize - key.offset;
 321         blocks = (new_item_span + root->sectorsize - 1) >>
 322                 root->fs_info->sb->s_blocksize_bits;
 323         new_item_size = blocks * BTRFS_CRC32_SIZE;
 324         if (new_item_size >= btrfs_item_size_nr(leaf, slot))
 325                 return 0;
 326         ret = btrfs_truncate_item(trans, root, path, new_item_size, 1);
 327         BUG_ON(ret);
 328         return ret;
 329 }
 330