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   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/fs.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/highmem.h>
  22 #include <linux/time.h>
  23 #include <linux/init.h>
  24 #include <linux/string.h>
  25 #include <linux/smp_lock.h>
  26 #include <linux/backing-dev.h>
  27 #include <linux/mpage.h>
  28 #include <linux/swap.h>
  29 #include <linux/writeback.h>
  30 #include <linux/statfs.h>
  31 #include <linux/compat.h>
  32 #include <linux/version.h>
  33 #include "ctree.h"
  34 #include "disk-io.h"
  35 #include "transaction.h"
  36 #include "btrfs_inode.h"
  37 #include "ioctl.h"
  38 #include "print-tree.h"
  39 #include "compat.h"
  40
  41
  42 static int btrfs_copy_from_user(loff_t pos, int num_pages, int write_bytes,
  43                                 struct page **prepared_pages,
  44                                 const char __user * buf)
  45 {
  46         long page_fault = 0;
  47         int i;
  48         int offset = pos & (PAGE_CACHE_SIZE - 1);
  49
  50         for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
  51                 size_t count = min_t(size_t,
  52                                      PAGE_CACHE_SIZE - offset, write_bytes);
  53                 struct page *page = prepared_pages[i];
  54                 fault_in_pages_readable(buf, count);
  55
  56                 /* Copy data from userspace to the current page */
  57                 kmap(page);
  58                 page_fault = __copy_from_user(page_address(page) + offset,
  59                                               buf, count);
  60                 /* Flush processor's dcache for this page */
  61                 flush_dcache_page(page);
  62                 kunmap(page);
  63                 buf += count;
  64                 write_bytes -= count;
  65
  66                 if (page_fault)
  67                         break;
  68         }
  69         return page_fault ? -EFAULT : 0;
  70 }
  71
  72 static void btrfs_drop_pages(struct page **pages, size_t num_pages)
  73 {
  74         size_t i;
  75         for (i = 0; i < num_pages; i++) {
  76                 if (!pages[i])
  77                         break;
  78                 unlock_page(pages[i]);
  79                 mark_page_accessed(pages[i]);
  80                 page_cache_release(pages[i]);
  81         }
  82 }
  83
  84 static int noinline insert_inline_extent(struct btrfs_trans_handle *trans,
  85                                 struct btrfs_root *root, struct inode *inode,
  86                                 u64 offset, size_t size,
  87                                 struct page **pages, size_t page_offset,
  88                                 int num_pages)
  89 {
  90         struct btrfs_key key;
  91         struct btrfs_path *path;
  92         struct extent_buffer *leaf;
  93         char *kaddr;
  94         unsigned long ptr;
  95         struct btrfs_file_extent_item *ei;
  96         struct page *page;
  97         u32 datasize;
  98         int err = 0;
  99         int ret;
 100         int i;
 101         ssize_t cur_size;
 102
 103         path = btrfs_alloc_path();
 104         if (!path)
 105                 return -ENOMEM;
 106
 107         btrfs_set_trans_block_group(trans, inode);
 108
 109         key.objectid = inode->i_ino;
 110         key.offset = offset;
 111         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
 112
 113         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
 114         if (ret < 0) {
 115                 err = ret;
 116                 goto fail;
 117         }
 118         if (ret == 1) {
 119                 struct btrfs_key found_key;
 120
 121                 if (path->slots[0] == 0)
 122                         goto insert;
 123
 124                 path->slots[0]--;
 125                 leaf = path->nodes[0];
 126                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 127
 128                 if (found_key.objectid != inode->i_ino)
 129                         goto insert;
 130
 131                 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
 132                         goto insert;
 133                 ei = btrfs_item_ptr(leaf, path->slots[0],
 134                                     struct btrfs_file_extent_item);
 135
 136                 if (btrfs_file_extent_type(leaf, ei) !=
 137                     BTRFS_FILE_EXTENT_INLINE) {
 138                         goto insert;
 139                 }
 140                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 141                 ret = 0;
 142         }
 143         if (ret == 0) {
 144                 u32 found_size;
 145                 u64 found_end;
 146
 147                 leaf = path->nodes[0];
 148                 ei = btrfs_item_ptr(leaf, path->slots[0],
 149                                     struct btrfs_file_extent_item);
 150
 151                 if (btrfs_file_extent_type(leaf, ei) !=
 152                     BTRFS_FILE_EXTENT_INLINE) {
 153                         err = ret;
 154                         btrfs_print_leaf(root, leaf);
 155                         printk("found wasn't inline offset %Lu inode %lu\n",
 156                                offset, inode->i_ino);
 157                         goto fail;
 158                 }
 159                 found_size = btrfs_file_extent_inline_len(leaf,
 160                                           btrfs_item_nr(leaf, path->slots[0]));
 161                 found_end = key.offset + found_size;
 162
 163                 if (found_end < offset + size) {
 164                         btrfs_release_path(root, path);
 165                         ret = btrfs_search_slot(trans, root, &key, path,
 166                                                 offset + size - found_end, 1);
 167                         BUG_ON(ret != 0);
 168
 169                         ret = btrfs_extend_item(trans, root, path,
 170                                                 offset + size - found_end);
 171                         if (ret) {
 172                                 err = ret;
 173                                 goto fail;
 174                         }
 175                         leaf = path->nodes[0];
 176                         ei = btrfs_item_ptr(leaf, path->slots[0],
 177                                             struct btrfs_file_extent_item);
 178                         inode->i_blocks += (offset + size - found_end) >> 9;
 179                 }
 180                 if (found_end < offset) {
 181                         ptr = btrfs_file_extent_inline_start(ei) + found_size;
 182                         memset_extent_buffer(leaf, 0, ptr, offset - found_end);
 183                 }
 184         } else {
 185 insert:
 186                 btrfs_release_path(root, path);
 187                 datasize = offset + size - key.offset;
 188                 inode->i_blocks += datasize >> 9;
 189                 datasize = btrfs_file_extent_calc_inline_size(datasize);
 190                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 191                                               datasize);
 192                 if (ret) {
 193                         err = ret;
 194                         printk("got bad ret %d\n", ret);
 195                         goto fail;
 196                 }
 197                 leaf = path->nodes[0];
 198                 ei = btrfs_item_ptr(leaf, path->slots[0],
 199                                     struct btrfs_file_extent_item);
 200                 btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 201                 btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 202         }
 203         ptr = btrfs_file_extent_inline_start(ei) + offset - key.offset;
 204
 205         cur_size = size;
 206         i = 0;
 207         while (size > 0) {
 208                 page = pages[i];
 209                 kaddr = kmap_atomic(page, KM_USER0);
 210                 cur_size = min_t(size_t, PAGE_CACHE_SIZE - page_offset, size);
 211                 write_extent_buffer(leaf, kaddr + page_offset, ptr, cur_size);
 212                 kunmap_atomic(kaddr, KM_USER0);
 213                 page_offset = 0;
 214                 ptr += cur_size;
 215                 size -= cur_size;
 216                 if (i >= num_pages) {
 217                         printk("i %d num_pages %d\n", i, num_pages);
 218                 }
 219                 i++;
 220         }
 221         btrfs_mark_buffer_dirty(leaf);
 222 fail:
 223         btrfs_free_path(path);
 224         return err;
 225 }
 226
 227 static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
 228                                    struct btrfs_root *root,
 229                                    struct file *file,
 230                                    struct page **pages,
 231                                    size_t num_pages,
 232                                    loff_t pos,
 233                                    size_t write_bytes)
 234 {
 235         int err = 0;
 236         int i;
 237         struct inode *inode = fdentry(file)->d_inode;
 238         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 239         u64 hint_byte;
 240         u64 num_bytes;
 241         u64 start_pos;
 242         u64 end_of_last_block;
 243         u64 end_pos = pos + write_bytes;
 244         u64 inline_size;
 245         int did_inline = 0;
 246         loff_t isize = i_size_read(inode);
 247
 248         start_pos = pos & ~((u64)root->sectorsize - 1);
 249         num_bytes = (write_bytes + pos - start_pos +
 250                     root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
 251
 252         end_of_last_block = start_pos + num_bytes - 1;
 253
 254         lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
 255         trans = btrfs_start_transaction(root, 1);
 256         if (!trans) {
 257                 err = -ENOMEM;
 258                 goto out_unlock;
 259         }
 260         btrfs_set_trans_block_group(trans, inode);
 261         hint_byte = 0;
 262
 263         if ((end_of_last_block & 4095) == 0) {
 264                 printk("strange end of last %Lu %zu %Lu\n", start_pos, write_bytes, end_of_last_block);
 265         }
 266         set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
 267
 268         /* FIXME...EIEIO, ENOSPC and more */
 269         /* insert any holes we need to create */
 270         if (isize < start_pos) {
 271                 u64 last_pos_in_file;
 272                 u64 hole_size;
 273                 u64 mask = root->sectorsize - 1;
 274                 last_pos_in_file = (isize + mask) & ~mask;
 275                 hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
 276                 if (hole_size > 0) {
 277                         btrfs_wait_ordered_range(inode, last_pos_in_file,
 278                                                  last_pos_in_file + hole_size);
 279                         mutex_lock(&BTRFS_I(inode)->extent_mutex);
 280                         err = btrfs_drop_extents(trans, root, inode,
 281                                                  last_pos_in_file,
 282                                                  last_pos_in_file + hole_size,
 283                                                  last_pos_in_file,
 284                                                  &hint_byte);
 285                         if (err)
 286                                 goto failed;
 287
 288                         err = btrfs_insert_file_extent(trans, root,
 289                                                        inode->i_ino,
 290                                                        last_pos_in_file,
 291                                                        0, 0, hole_size, 0);
 292                         btrfs_drop_extent_cache(inode, last_pos_in_file,
 293                                         last_pos_in_file + hole_size -1);
 294                         mutex_unlock(&BTRFS_I(inode)->extent_mutex);
 295                         btrfs_check_file(root, inode);
 296                 }
 297                 if (err)
 298                         goto failed;
 299         }
 300
 301         /*
 302          * either allocate an extent for the new bytes or setup the key
 303          * to show we are doing inline data in the extent
 304          */
 305         inline_size = end_pos;
 306         if (isize >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 307             inline_size > root->fs_info->max_inline ||
 308             (inline_size & (root->sectorsize -1)) == 0 ||
 309             inline_size >= BTRFS_MAX_INLINE_DATA_SIZE(root)) {
 310                 /* check for reserved extents on each page, we don't want
 311                  * to reset the delalloc bit on things that already have
 312                  * extents reserved.
 313                  */
 314                 set_extent_delalloc(io_tree, start_pos,
 315                                     end_of_last_block, GFP_NOFS);
 316                 for (i = 0; i < num_pages; i++) {
 317                         struct page *p = pages[i];
 318                         SetPageUptodate(p);
 319                         ClearPageChecked(p);
 320                         set_page_dirty(p);
 321                 }
 322         } else {
 323                 u64 aligned_end;
 324                 /* step one, delete the existing extents in this range */
 325                 aligned_end = (pos + write_bytes + root->sectorsize - 1) &
 326                         ~((u64)root->sectorsize - 1);
 327                 mutex_lock(&BTRFS_I(inode)->extent_mutex);
 328                 err = btrfs_drop_extents(trans, root, inode, start_pos,
 329                                          aligned_end, aligned_end, &hint_byte);
 330                 if (err)
 331                         goto failed;
 332                 if (isize > inline_size)
 333                         inline_size = min_t(u64, isize, aligned_end);
 334                 inline_size -= start_pos;
 335                 err = insert_inline_extent(trans, root, inode, start_pos,
 336                                            inline_size, pages, 0, num_pages);
 337                 btrfs_drop_extent_cache(inode, start_pos, aligned_end - 1);
 338                 BUG_ON(err);
 339                 mutex_unlock(&BTRFS_I(inode)->extent_mutex);
 340                 did_inline = 1;
 341         }
 342         if (end_pos > isize) {
 343                 i_size_write(inode, end_pos);
 344                 if (did_inline)
 345                         BTRFS_I(inode)->disk_i_size = end_pos;
 346                 btrfs_update_inode(trans, root, inode);
 347         }
 348 failed:
 349         err = btrfs_end_transaction_throttle(trans, root);
 350 out_unlock:
 351         unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
 352         return err;
 353 }
 354
 355 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end)
 356 {
 357         struct extent_map *em;
 358         struct extent_map *split = NULL;
 359         struct extent_map *split2 = NULL;
 360         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 361         struct extent_map *tmp;
 362         u64 len = end - start + 1;
 363         u64 next_start;
 364         int ret;
 365         int testend = 1;
 366
 367         WARN_ON(end < start);
 368         if (end == (u64)-1) {
 369                 len = (u64)-1;
 370                 testend = 0;
 371         }
 372         while(1) {
 373                 if (!split)
 374                         split = alloc_extent_map(GFP_NOFS);
 375                 if (!split2)
 376                         split2 = alloc_extent_map(GFP_NOFS);
 377
 378                 spin_lock(&em_tree->lock);
 379                 em = lookup_extent_mapping(em_tree, start, len);
 380                 if (!em) {
 381                         spin_unlock(&em_tree->lock);
 382                         break;
 383                 }
 384                 tmp = rb_entry(&em->rb_node, struct extent_map, rb_node);
 385                 next_start = tmp->start;
 386                 remove_extent_mapping(em_tree, em);
 387
 388                 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
 389                     em->start < start) {
 390                         split->start = em->start;
 391                         split->len = start - em->start;
 392                         split->block_start = em->block_start;
 393                         split->bdev = em->bdev;
 394                         split->flags = em->flags;
 395                         ret = add_extent_mapping(em_tree, split);
 396                         BUG_ON(ret);
 397                         free_extent_map(split);
 398                         split = split2;
 399                         split2 = NULL;
 400                 }
 401                 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
 402                     testend && em->start + em->len > start + len) {
 403                         u64 diff = start + len - em->start;
 404
 405                         split->start = start + len;
 406                         split->len = em->start + em->len - (start + len);
 407                         split->bdev = em->bdev;
 408                         split->flags = em->flags;
 409
 410                         split->block_start = em->block_start + diff;
 411
 412                         ret = add_extent_mapping(em_tree, split);
 413                         BUG_ON(ret);
 414                         free_extent_map(split);
 415                         split = NULL;
 416                 }
 417                 spin_unlock(&em_tree->lock);
 418
 419                 /* once for us */
 420                 free_extent_map(em);
 421                 /* once for the tree*/
 422                 free_extent_map(em);
 423         }
 424         if (split)
 425                 free_extent_map(split);
 426         if (split2)
 427                 free_extent_map(split2);
 428         return 0;
 429 }
 430
 431 int btrfs_check_file(struct btrfs_root *root, struct inode *inode)
 432 {
 433         return 0;
 434 #if 0
 435         struct btrfs_path *path;
 436         struct btrfs_key found_key;
 437         struct extent_buffer *leaf;
 438         struct btrfs_file_extent_item *extent;
 439         u64 last_offset = 0;
 440         int nritems;
 441         int slot;
 442         int found_type;
 443         int ret;
 444         int err = 0;
 445         u64 extent_end = 0;
 446
 447         path = btrfs_alloc_path();
 448         ret = btrfs_lookup_file_extent(NULL, root, path, inode->i_ino,
 449                                        last_offset, 0);
 450         while(1) {
 451                 nritems = btrfs_header_nritems(path->nodes[0]);
 452                 if (path->slots[0] >= nritems) {
 453                         ret = btrfs_next_leaf(root, path);
 454                         if (ret)
 455                                 goto out;
 456                         nritems = btrfs_header_nritems(path->nodes[0]);
 457                 }
 458                 slot = path->slots[0];
 459                 leaf = path->nodes[0];
 460                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
 461                 if (found_key.objectid != inode->i_ino)
 462                         break;
 463                 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
 464                         goto out;
 465
 466                 if (found_key.offset < last_offset) {
 467                         WARN_ON(1);
 468                         btrfs_print_leaf(root, leaf);
 469                         printk("inode %lu found offset %Lu expected %Lu\n",
 470                                inode->i_ino, found_key.offset, last_offset);
 471                         err = 1;
 472                         goto out;
 473                 }
 474                 extent = btrfs_item_ptr(leaf, slot,
 475                                         struct btrfs_file_extent_item);
 476                 found_type = btrfs_file_extent_type(leaf, extent);
 477                 if (found_type == BTRFS_FILE_EXTENT_REG) {
 478                         extent_end = found_key.offset +
 479                              btrfs_file_extent_num_bytes(leaf, extent);
 480                 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
 481                         struct btrfs_item *item;
 482                         item = btrfs_item_nr(leaf, slot);
 483                         extent_end = found_key.offset +
 484                              btrfs_file_extent_inline_len(leaf, item);
 485                         extent_end = (extent_end + root->sectorsize - 1) &
 486                                 ~((u64)root->sectorsize -1 );
 487                 }
 488                 last_offset = extent_end;
 489                 path->slots[0]++;
 490         }
 491         if (0 && last_offset < inode->i_size) {
 492                 WARN_ON(1);
 493                 btrfs_print_leaf(root, leaf);
 494                 printk("inode %lu found offset %Lu size %Lu\n", inode->i_ino,
 495                        last_offset, inode->i_size);
 496                 err = 1;
 497
 498         }
 499 out:
 500         btrfs_free_path(path);
 501         return err;
 502 #endif
 503 }
 504
 505 /*
 506  * this is very complex, but the basic idea is to drop all extents
 507  * in the range start - end.  hint_block is filled in with a block number
 508  * that would be a good hint to the block allocator for this file.
 509  *
 510  * If an extent intersects the range but is not entirely inside the range
 511  * it is either truncated or split.  Anything entirely inside the range
 512  * is deleted from the tree.
 513  */
 514 int btrfs_drop_extents(struct btrfs_trans_handle *trans,
 515                        struct btrfs_root *root, struct inode *inode,
 516                        u64 start, u64 end, u64 inline_limit, u64 *hint_byte)
 517 {
 518         u64 extent_end = 0;
 519         u64 search_start = start;
 520         struct extent_buffer *leaf;
 521         struct btrfs_file_extent_item *extent;
 522         struct btrfs_path *path;
 523         struct btrfs_key key;
 524         struct btrfs_file_extent_item old;
 525         int keep;
 526         int slot;
 527         int bookend;
 528         int found_type;
 529         int found_extent;
 530         int found_inline;
 531         int recow;
 532         int ret;
 533
 534         btrfs_drop_extent_cache(inode, start, end - 1);
 535
 536         path = btrfs_alloc_path();
 537         if (!path)
 538                 return -ENOMEM;
 539         while(1) {
 540                 recow = 0;
 541                 btrfs_release_path(root, path);
 542                 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
 543                                                search_start, -1);
 544                 if (ret < 0)
 545                         goto out;
 546                 if (ret > 0) {
 547                         if (path->slots[0] == 0) {
 548                                 ret = 0;
 549                                 goto out;
 550                         }
 551                         path->slots[0]--;
 552                 }
 553 next_slot:
 554                 keep = 0;
 555                 bookend = 0;
 556                 found_extent = 0;
 557                 found_inline = 0;
 558                 extent = NULL;
 559                 leaf = path->nodes[0];
 560                 slot = path->slots[0];
 561                 ret = 0;
 562                 btrfs_item_key_to_cpu(leaf, &key, slot);
 563                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
 564                     key.offset >= end) {
 565                         goto out;
 566                 }
 567                 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
 568                     key.objectid != inode->i_ino) {
 569                         goto out;
 570                 }
 571                 if (recow) {
 572                         search_start = key.offset;
 573                         continue;
 574                 }
 575                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
 576                         extent = btrfs_item_ptr(leaf, slot,
 577                                                 struct btrfs_file_extent_item);
 578                         found_type = btrfs_file_extent_type(leaf, extent);
 579                         if (found_type == BTRFS_FILE_EXTENT_REG) {
 580                                 extent_end =
 581                                      btrfs_file_extent_disk_bytenr(leaf,
 582                                                                    extent);
 583                                 if (extent_end)
 584                                         *hint_byte = extent_end;
 585
 586                                 extent_end = key.offset +
 587                                      btrfs_file_extent_num_bytes(leaf, extent);
 588                                 found_extent = 1;
 589                         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
 590                                 struct btrfs_item *item;
 591                                 item = btrfs_item_nr(leaf, slot);
 592                                 found_inline = 1;
 593                                 extent_end = key.offset +
 594                                      btrfs_file_extent_inline_len(leaf, item);
 595                         }
 596                 } else {
 597                         extent_end = search_start;
 598                 }
 599
 600                 /* we found nothing we can drop */
 601                 if ((!found_extent && !found_inline) ||
 602                     search_start >= extent_end) {
 603                         int nextret;
 604                         u32 nritems;
 605                         nritems = btrfs_header_nritems(leaf);
 606                         if (slot >= nritems - 1) {
 607                                 nextret = btrfs_next_leaf(root, path);
 608                                 if (nextret)
 609                                         goto out;
 610                                 recow = 1;
 611                         } else {
 612                                 path->slots[0]++;
 613                         }
 614                         goto next_slot;
 615                 }
 616
 617                 if (found_inline) {
 618                         u64 mask = root->sectorsize - 1;
 619                         search_start = (extent_end + mask) & ~mask;
 620                 } else
 621                         search_start = extent_end;
 622                 if (end <= extent_end && start >= key.offset && found_inline) {
 623                         *hint_byte = EXTENT_MAP_INLINE;
 624                         continue;
 625                 }
 626                 if (end < extent_end && end >= key.offset) {
 627                         if (found_extent) {
 628                                 u64 disk_bytenr =
 629                                     btrfs_file_extent_disk_bytenr(leaf, extent);
 630                                 u64 disk_num_bytes =
 631                                     btrfs_file_extent_disk_num_bytes(leaf,
 632                                                                       extent);
 633                                 read_extent_buffer(leaf, &old,
 634                                                    (unsigned long)extent,
 635                                                    sizeof(old));
 636                                 if (disk_bytenr != 0) {
 637                                         ret = btrfs_inc_extent_ref(trans, root,
 638                                                  disk_bytenr, disk_num_bytes,
 639                                                  root->root_key.objectid,
 640                                                  trans->transid,
 641                                                  key.objectid, end);
 642                                         BUG_ON(ret);
 643                                 }
 644                         }
 645                         bookend = 1;
 646                         if (found_inline && start <= key.offset)
 647                                 keep = 1;
 648                 }
 649                 /* truncate existing extent */
 650                 if (start > key.offset) {
 651                         u64 new_num;
 652                         u64 old_num;
 653                         keep = 1;
 654                         WARN_ON(start & (root->sectorsize - 1));
 655                         if (found_extent) {
 656                                 new_num = start - key.offset;
 657                                 old_num = btrfs_file_extent_num_bytes(leaf,
 658                                                                       extent);
 659                                 *hint_byte =
 660                                         btrfs_file_extent_disk_bytenr(leaf,
 661                                                                       extent);
 662                                 if (btrfs_file_extent_disk_bytenr(leaf,
 663                                                                   extent)) {
 664                                         dec_i_blocks(inode, old_num - new_num);
 665                                 }
 666                                 btrfs_set_file_extent_num_bytes(leaf, extent,
 667                                                                 new_num);
 668                                 btrfs_mark_buffer_dirty(leaf);
 669                         } else if (key.offset < inline_limit &&
 670                                    (end > extent_end) &&
 671                                    (inline_limit < extent_end)) {
 672                                 u32 new_size;
 673                                 new_size = btrfs_file_extent_calc_inline_size(
 674                                                    inline_limit - key.offset);
 675                                 dec_i_blocks(inode, (extent_end - key.offset) -
 676                                         (inline_limit - key.offset));
 677                                 btrfs_truncate_item(trans, root, path,
 678                                                     new_size, 1);
 679                         }
 680                 }
 681                 /* delete the entire extent */
 682                 if (!keep) {
 683                         u64 disk_bytenr = 0;
 684                         u64 disk_num_bytes = 0;
 685                         u64 extent_num_bytes = 0;
 686                         u64 root_gen;
 687                         u64 root_owner;
 688
 689                         root_gen = btrfs_header_generation(leaf);
 690                         root_owner = btrfs_header_owner(leaf);
 691                         if (found_extent) {
 692                                 disk_bytenr =
 693                                       btrfs_file_extent_disk_bytenr(leaf,
 694                                                                      extent);
 695                                 disk_num_bytes =
 696                                       btrfs_file_extent_disk_num_bytes(leaf,
 697                                                                        extent);
 698                                 extent_num_bytes =
 699                                       btrfs_file_extent_num_bytes(leaf, extent);
 700                                 *hint_byte =
 701                                         btrfs_file_extent_disk_bytenr(leaf,
 702                                                                       extent);
 703                         }
 704                         ret = btrfs_del_item(trans, root, path);
 705                         /* TODO update progress marker and return */
 706                         BUG_ON(ret);
 707                         btrfs_release_path(root, path);
 708                         extent = NULL;
 709                         if (found_extent && disk_bytenr != 0) {
 710                                 dec_i_blocks(inode, extent_num_bytes);
 711                                 ret = btrfs_free_extent(trans, root,
 712                                                 disk_bytenr,
 713                                                 disk_num_bytes,
 714                                                 root_owner,
 715                                                 root_gen, inode->i_ino,
 716                                                 key.offset, 0);
 717                         }
 718
 719                         BUG_ON(ret);
 720                         if (!bookend && search_start >= end) {
 721                                 ret = 0;
 722                                 goto out;
 723                         }
 724                         if (!bookend)
 725                                 continue;
 726                 }
 727                 if (bookend && found_inline && start <= key.offset) {
 728                         u32 new_size;
 729                         new_size = btrfs_file_extent_calc_inline_size(
 730                                                    extent_end - end);
 731                         dec_i_blocks(inode, (extent_end - key.offset) -
 732                                         (extent_end - end));
 733                         btrfs_truncate_item(trans, root, path, new_size, 0);
 734                 }
 735                 /* create bookend, splitting the extent in two */
 736                 if (bookend && found_extent) {
 737                         struct btrfs_key ins;
 738                         ins.objectid = inode->i_ino;
 739                         ins.offset = end;
 740                         btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
 741                         btrfs_release_path(root, path);
 742                         ret = btrfs_insert_empty_item(trans, root, path, &ins,
 743                                                       sizeof(*extent));
 744
 745                         leaf = path->nodes[0];
 746                         if (ret) {
 747                                 btrfs_print_leaf(root, leaf);
 748                                 printk("got %d on inserting %Lu %u %Lu start %Lu end %Lu found %Lu %Lu keep was %d\n", ret , ins.objectid, ins.type, ins.offset, start, end, key.offset, extent_end, keep);
 749                         }
 750                         BUG_ON(ret);
 751                         extent = btrfs_item_ptr(leaf, path->slots[0],
 752                                                 struct btrfs_file_extent_item);
 753                         write_extent_buffer(leaf, &old,
 754                                             (unsigned long)extent, sizeof(old));
 755
 756                         btrfs_set_file_extent_offset(leaf, extent,
 757                                     le64_to_cpu(old.offset) + end - key.offset);
 758                         WARN_ON(le64_to_cpu(old.num_bytes) <
 759                                 (extent_end - end));
 760                         btrfs_set_file_extent_num_bytes(leaf, extent,
 761                                                         extent_end - end);
 762                         btrfs_set_file_extent_type(leaf, extent,
 763                                                    BTRFS_FILE_EXTENT_REG);
 764
 765                         btrfs_mark_buffer_dirty(path->nodes[0]);
 766                         if (le64_to_cpu(old.disk_bytenr) != 0) {
 767                                 inode->i_blocks +=
 768                                       btrfs_file_extent_num_bytes(leaf,
 769                                                                   extent) >> 9;
 770                         }
 771                         ret = 0;
 772                         goto out;
 773                 }
 774         }
 775 out:
 776         btrfs_free_path(path);
 777         btrfs_check_file(root, inode);
 778         return ret;
 779 }
 780
 781 /*
 782  * this gets pages into the page cache and locks them down
 783  */
 784 static int prepare_pages(struct btrfs_root *root, struct file *file,
 785                          struct page **pages, size_t num_pages,
 786                          loff_t pos, unsigned long first_index,
 787                          unsigned long last_index, size_t write_bytes)
 788 {
 789         int i;
 790         unsigned long index = pos >> PAGE_CACHE_SHIFT;
 791         struct inode *inode = fdentry(file)->d_inode;
 792         int err = 0;
 793         u64 start_pos;
 794         u64 last_pos;
 795
 796         start_pos = pos & ~((u64)root->sectorsize - 1);
 797         last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
 798
 799         memset(pages, 0, num_pages * sizeof(struct page *));
 800 again:
 801         for (i = 0; i < num_pages; i++) {
 802                 pages[i] = grab_cache_page(inode->i_mapping, index + i);
 803                 if (!pages[i]) {
 804                         err = -ENOMEM;
 805                         BUG_ON(1);
 806                 }
 807                 wait_on_page_writeback(pages[i]);
 808         }
 809         if (start_pos < inode->i_size) {
 810                 struct btrfs_ordered_extent *ordered;
 811                 lock_extent(&BTRFS_I(inode)->io_tree,
 812                             start_pos, last_pos - 1, GFP_NOFS);
 813                 ordered = btrfs_lookup_first_ordered_extent(inode, last_pos -1);
 814                 if (ordered &&
 815                     ordered->file_offset + ordered->len > start_pos &&
 816                     ordered->file_offset < last_pos) {
 817                         btrfs_put_ordered_extent(ordered);
 818                         unlock_extent(&BTRFS_I(inode)->io_tree,
 819                                       start_pos, last_pos - 1, GFP_NOFS);
 820                         for (i = 0; i < num_pages; i++) {
 821                                 unlock_page(pages[i]);
 822                                 page_cache_release(pages[i]);
 823                         }
 824                         btrfs_wait_ordered_range(inode, start_pos,
 825                                                  last_pos - start_pos);
 826                         goto again;
 827                 }
 828                 if (ordered)
 829                         btrfs_put_ordered_extent(ordered);
 830
 831                 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
 832                                   last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
 833                                   GFP_NOFS);
 834                 unlock_extent(&BTRFS_I(inode)->io_tree,
 835                               start_pos, last_pos - 1, GFP_NOFS);
 836         }
 837         for (i = 0; i < num_pages; i++) {
 838 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
 839                 ClearPageDirty(pages[i]);
 840 #else
 841                 cancel_dirty_page(pages[i], PAGE_CACHE_SIZE);
 842 #endif
 843                 set_page_extent_mapped(pages[i]);
 844                 WARN_ON(!PageLocked(pages[i]));
 845         }
 846         return 0;
 847 }
 848
 849 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
 850                                 size_t count, loff_t *ppos)
 851 {
 852         loff_t pos;
 853         loff_t start_pos;
 854         ssize_t num_written = 0;
 855         ssize_t err = 0;
 856         int ret = 0;
 857         struct inode *inode = fdentry(file)->d_inode;
 858         struct btrfs_root *root = BTRFS_I(inode)->root;
 859         struct page **pages = NULL;
 860         int nrptrs;
 861         struct page *pinned[2];
 862         unsigned long first_index;
 863         unsigned long last_index;
 864
 865         nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
 866                      PAGE_CACHE_SIZE / (sizeof(struct page *)));
 867         pinned[0] = NULL;
 868         pinned[1] = NULL;
 869
 870         pos = *ppos;
 871         start_pos = pos;
 872
 873         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
 874         current->backing_dev_info = inode->i_mapping->backing_dev_info;
 875         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
 876         if (err)
 877                 goto out_nolock;
 878         if (count == 0)
 879                 goto out_nolock;
 880 #ifdef REMOVE_SUID_PATH
 881         err = remove_suid(&file->f_path);
 882 #else
 883         err = remove_suid(fdentry(file));
 884 #endif
 885         if (err)
 886                 goto out_nolock;
 887         file_update_time(file);
 888
 889         pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
 890
 891         mutex_lock(&inode->i_mutex);
 892         first_index = pos >> PAGE_CACHE_SHIFT;
 893         last_index = (pos + count) >> PAGE_CACHE_SHIFT;
 894
 895         /*
 896          * if this is a nodatasum mount, force summing off for the inode
 897          * all the time.  That way a later mount with summing on won't
 898          * get confused
 899          */
 900         if (btrfs_test_opt(root, NODATASUM))
 901                 btrfs_set_flag(inode, NODATASUM);
 902
 903         /*
 904          * there are lots of better ways to do this, but this code
 905          * makes sure the first and last page in the file range are
 906          * up to date and ready for cow
 907          */
 908         if ((pos & (PAGE_CACHE_SIZE - 1))) {
 909                 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
 910                 if (!PageUptodate(pinned[0])) {
 911                         ret = btrfs_readpage(NULL, pinned[0]);
 912                         BUG_ON(ret);
 913                         wait_on_page_locked(pinned[0]);
 914                 } else {
 915                         unlock_page(pinned[0]);
 916                 }
 917         }
 918         if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
 919                 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
 920                 if (!PageUptodate(pinned[1])) {
 921                         ret = btrfs_readpage(NULL, pinned[1]);
 922                         BUG_ON(ret);
 923                         wait_on_page_locked(pinned[1]);
 924                 } else {
 925                         unlock_page(pinned[1]);
 926                 }
 927         }
 928
 929         while(count > 0) {
 930                 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
 931                 size_t write_bytes = min(count, nrptrs *
 932                                         (size_t)PAGE_CACHE_SIZE -
 933                                          offset);
 934                 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
 935                                         PAGE_CACHE_SHIFT;
 936
 937                 WARN_ON(num_pages > nrptrs);
 938                 memset(pages, 0, sizeof(pages));
 939
 940                 ret = btrfs_check_free_space(root, write_bytes, 0);
 941                 if (ret)
 942                         goto out;
 943
 944                 ret = prepare_pages(root, file, pages, num_pages,
 945                                     pos, first_index, last_index,
 946                                     write_bytes);
 947                 if (ret)
 948                         goto out;
 949
 950                 ret = btrfs_copy_from_user(pos, num_pages,
 951                                            write_bytes, pages, buf);
 952                 if (ret) {
 953                         btrfs_drop_pages(pages, num_pages);
 954                         goto out;
 955                 }
 956
 957                 ret = dirty_and_release_pages(NULL, root, file, pages,
 958                                               num_pages, pos, write_bytes);
 959                 btrfs_drop_pages(pages, num_pages);
 960                 if (ret)
 961                         goto out;
 962
 963                 buf += write_bytes;
 964                 count -= write_bytes;
 965                 pos += write_bytes;
 966                 num_written += write_bytes;
 967
 968                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, num_pages);
 969                 if (num_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
 970                         btrfs_btree_balance_dirty(root, 1);
 971                 cond_resched();
 972         }
 973 out:
 974         mutex_unlock(&inode->i_mutex);
 975
 976 out_nolock:
 977         kfree(pages);
 978         if (pinned[0])
 979                 page_cache_release(pinned[0]);
 980         if (pinned[1])
 981                 page_cache_release(pinned[1]);
 982         *ppos = pos;
 983
 984         if (num_written > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
 985                 err = sync_page_range(inode, inode->i_mapping,
 986                                       start_pos, num_written);
 987                 if (err < 0)
 988                         num_written = err;
 989         } else if (num_written > 0 && (file->f_flags & O_DIRECT)) {
 990 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22)
 991                 do_sync_file_range(file, start_pos,
 992                                       start_pos + num_written - 1,
 993                                       SYNC_FILE_RANGE_WRITE |
 994                                       SYNC_FILE_RANGE_WAIT_AFTER);
 995 #else
 996                 do_sync_mapping_range(inode->i_mapping, start_pos,
 997                                       start_pos + num_written - 1,
 998                                       SYNC_FILE_RANGE_WRITE |
 999                                       SYNC_FILE_RANGE_WAIT_AFTER);
1000 #endif
1001                 invalidate_mapping_pages(inode->i_mapping,
1002                       start_pos >> PAGE_CACHE_SHIFT,
1003                      (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1004         }
1005         current->backing_dev_info = NULL;
1006         return num_written ? num_written : err;
1007 }
1008
1009 int btrfs_release_file(struct inode * inode, struct file * filp)
1010 {
1011         if (filp->private_data)
1012                 btrfs_ioctl_trans_end(filp);
1013         return 0;
1014 }
1015
1016 static int btrfs_sync_file(struct file *file,
1017                            struct dentry *dentry, int datasync)
1018 {
1019         struct inode *inode = dentry->d_inode;
1020         struct btrfs_root *root = BTRFS_I(inode)->root;
1021         int ret = 0;
1022         struct btrfs_trans_handle *trans;
1023
1024         /*
1025          * check the transaction that last modified this inode
1026          * and see if its already been committed
1027          */
1028         if (!BTRFS_I(inode)->last_trans)
1029                 goto out;
1030
1031         mutex_lock(&root->fs_info->trans_mutex);
1032         if (BTRFS_I(inode)->last_trans <=
1033             root->fs_info->last_trans_committed) {
1034                 BTRFS_I(inode)->last_trans = 0;
1035                 mutex_unlock(&root->fs_info->trans_mutex);
1036                 goto out;
1037         }
1038         mutex_unlock(&root->fs_info->trans_mutex);
1039
1040         /*
1041          * ok we haven't committed the transaction yet, lets do a commit
1042          */
1043         if (file->private_data)
1044                 btrfs_ioctl_trans_end(file);
1045
1046         trans = btrfs_start_transaction(root, 1);
1047         if (!trans) {
1048                 ret = -ENOMEM;
1049                 goto out;
1050         }
1051         ret = btrfs_commit_transaction(trans, root);
1052 out:
1053         return ret > 0 ? EIO : ret;
1054 }
1055
1056 static struct vm_operations_struct btrfs_file_vm_ops = {
1057 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
1058         .nopage         = filemap_nopage,
1059         .populate       = filemap_populate,
1060 #else
1061         .fault          = filemap_fault,
1062 #endif
1063         .page_mkwrite   = btrfs_page_mkwrite,
1064 };
1065
1066 static int btrfs_file_mmap(struct file  *filp, struct vm_area_struct *vma)
1067 {
1068         vma->vm_ops = &btrfs_file_vm_ops;
1069         file_accessed(filp);
1070         return 0;
1071 }
1072
1073 struct file_operations btrfs_file_operations = {
1074         .llseek         = generic_file_llseek,
1075         .read           = do_sync_read,
1076         .aio_read       = generic_file_aio_read,
1077         .splice_read    = generic_file_splice_read,
1078 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
1079         .sendfile       = generic_file_sendfile,
1080 #endif
1081         .write          = btrfs_file_write,
1082         .mmap           = btrfs_file_mmap,
1083         .open           = generic_file_open,
1084         .release        = btrfs_release_file,
1085         .fsync          = btrfs_sync_file,
1086         .unlocked_ioctl = btrfs_ioctl,
1087 #ifdef CONFIG_COMPAT
1088         .compat_ioctl   = btrfs_ioctl,
1089 #endif
1090 };
1091