Btrfs: kill root from btrfs_is_free_space_inode
[linux-3.10.git] / fs / btrfs / inode.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/kernel.h>
20 #include <linux/bio.h>
21 #include <linux/buffer_head.h>
22 #include <linux/file.h>
23 #include <linux/fs.h>
24 #include <linux/pagemap.h>
25 #include <linux/highmem.h>
26 #include <linux/time.h>
27 #include <linux/init.h>
28 #include <linux/string.h>
29 #include <linux/backing-dev.h>
30 #include <linux/mpage.h>
31 #include <linux/swap.h>
32 #include <linux/writeback.h>
33 #include <linux/statfs.h>
34 #include <linux/compat.h>
35 #include <linux/bit_spinlock.h>
36 #include <linux/xattr.h>
37 #include <linux/posix_acl.h>
38 #include <linux/falloc.h>
39 #include <linux/slab.h>
40 #include <linux/ratelimit.h>
41 #include <linux/mount.h>
42 #include "compat.h"
43 #include "ctree.h"
44 #include "disk-io.h"
45 #include "transaction.h"
46 #include "btrfs_inode.h"
47 #include "ioctl.h"
48 #include "print-tree.h"
49 #include "ordered-data.h"
50 #include "xattr.h"
51 #include "tree-log.h"
52 #include "volumes.h"
53 #include "compression.h"
54 #include "locking.h"
55 #include "free-space-cache.h"
56 #include "inode-map.h"
57
58 struct btrfs_iget_args {
59         u64 ino;
60         struct btrfs_root *root;
61 };
62
63 static const struct inode_operations btrfs_dir_inode_operations;
64 static const struct inode_operations btrfs_symlink_inode_operations;
65 static const struct inode_operations btrfs_dir_ro_inode_operations;
66 static const struct inode_operations btrfs_special_inode_operations;
67 static const struct inode_operations btrfs_file_inode_operations;
68 static const struct address_space_operations btrfs_aops;
69 static const struct address_space_operations btrfs_symlink_aops;
70 static const struct file_operations btrfs_dir_file_operations;
71 static struct extent_io_ops btrfs_extent_io_ops;
72
73 static struct kmem_cache *btrfs_inode_cachep;
74 struct kmem_cache *btrfs_trans_handle_cachep;
75 struct kmem_cache *btrfs_transaction_cachep;
76 struct kmem_cache *btrfs_path_cachep;
77 struct kmem_cache *btrfs_free_space_cachep;
78
79 #define S_SHIFT 12
80 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
81         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
82         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
83         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
84         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
85         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
86         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
87         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
88 };
89
90 static int btrfs_setsize(struct inode *inode, loff_t newsize);
91 static int btrfs_truncate(struct inode *inode);
92 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
93 static noinline int cow_file_range(struct inode *inode,
94                                    struct page *locked_page,
95                                    u64 start, u64 end, int *page_started,
96                                    unsigned long *nr_written, int unlock);
97 static noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
98                                 struct btrfs_root *root, struct inode *inode);
99
100 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
101                                      struct inode *inode,  struct inode *dir,
102                                      const struct qstr *qstr)
103 {
104         int err;
105
106         err = btrfs_init_acl(trans, inode, dir);
107         if (!err)
108                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
109         return err;
110 }
111
112 /*
113  * this does all the hard work for inserting an inline extent into
114  * the btree.  The caller should have done a btrfs_drop_extents so that
115  * no overlapping inline items exist in the btree
116  */
117 static noinline int insert_inline_extent(struct btrfs_trans_handle *trans,
118                                 struct btrfs_root *root, struct inode *inode,
119                                 u64 start, size_t size, size_t compressed_size,
120                                 int compress_type,
121                                 struct page **compressed_pages)
122 {
123         struct btrfs_key key;
124         struct btrfs_path *path;
125         struct extent_buffer *leaf;
126         struct page *page = NULL;
127         char *kaddr;
128         unsigned long ptr;
129         struct btrfs_file_extent_item *ei;
130         int err = 0;
131         int ret;
132         size_t cur_size = size;
133         size_t datasize;
134         unsigned long offset;
135
136         if (compressed_size && compressed_pages)
137                 cur_size = compressed_size;
138
139         path = btrfs_alloc_path();
140         if (!path)
141                 return -ENOMEM;
142
143         path->leave_spinning = 1;
144
145         key.objectid = btrfs_ino(inode);
146         key.offset = start;
147         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
148         datasize = btrfs_file_extent_calc_inline_size(cur_size);
149
150         inode_add_bytes(inode, size);
151         ret = btrfs_insert_empty_item(trans, root, path, &key,
152                                       datasize);
153         if (ret) {
154                 err = ret;
155                 goto fail;
156         }
157         leaf = path->nodes[0];
158         ei = btrfs_item_ptr(leaf, path->slots[0],
159                             struct btrfs_file_extent_item);
160         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
161         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
162         btrfs_set_file_extent_encryption(leaf, ei, 0);
163         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
164         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
165         ptr = btrfs_file_extent_inline_start(ei);
166
167         if (compress_type != BTRFS_COMPRESS_NONE) {
168                 struct page *cpage;
169                 int i = 0;
170                 while (compressed_size > 0) {
171                         cpage = compressed_pages[i];
172                         cur_size = min_t(unsigned long, compressed_size,
173                                        PAGE_CACHE_SIZE);
174
175                         kaddr = kmap_atomic(cpage);
176                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
177                         kunmap_atomic(kaddr);
178
179                         i++;
180                         ptr += cur_size;
181                         compressed_size -= cur_size;
182                 }
183                 btrfs_set_file_extent_compression(leaf, ei,
184                                                   compress_type);
185         } else {
186                 page = find_get_page(inode->i_mapping,
187                                      start >> PAGE_CACHE_SHIFT);
188                 btrfs_set_file_extent_compression(leaf, ei, 0);
189                 kaddr = kmap_atomic(page);
190                 offset = start & (PAGE_CACHE_SIZE - 1);
191                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
192                 kunmap_atomic(kaddr);
193                 page_cache_release(page);
194         }
195         btrfs_mark_buffer_dirty(leaf);
196         btrfs_free_path(path);
197
198         /*
199          * we're an inline extent, so nobody can
200          * extend the file past i_size without locking
201          * a page we already have locked.
202          *
203          * We must do any isize and inode updates
204          * before we unlock the pages.  Otherwise we
205          * could end up racing with unlink.
206          */
207         BTRFS_I(inode)->disk_i_size = inode->i_size;
208         ret = btrfs_update_inode(trans, root, inode);
209
210         return ret;
211 fail:
212         btrfs_free_path(path);
213         return err;
214 }
215
216
217 /*
218  * conditionally insert an inline extent into the file.  This
219  * does the checks required to make sure the data is small enough
220  * to fit as an inline extent.
221  */
222 static noinline int cow_file_range_inline(struct btrfs_trans_handle *trans,
223                                  struct btrfs_root *root,
224                                  struct inode *inode, u64 start, u64 end,
225                                  size_t compressed_size, int compress_type,
226                                  struct page **compressed_pages)
227 {
228         u64 isize = i_size_read(inode);
229         u64 actual_end = min(end + 1, isize);
230         u64 inline_len = actual_end - start;
231         u64 aligned_end = (end + root->sectorsize - 1) &
232                         ~((u64)root->sectorsize - 1);
233         u64 hint_byte;
234         u64 data_len = inline_len;
235         int ret;
236
237         if (compressed_size)
238                 data_len = compressed_size;
239
240         if (start > 0 ||
241             actual_end >= PAGE_CACHE_SIZE ||
242             data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
243             (!compressed_size &&
244             (actual_end & (root->sectorsize - 1)) == 0) ||
245             end + 1 < isize ||
246             data_len > root->fs_info->max_inline) {
247                 return 1;
248         }
249
250         ret = btrfs_drop_extents(trans, inode, start, aligned_end,
251                                  &hint_byte, 1);
252         if (ret)
253                 return ret;
254
255         if (isize > actual_end)
256                 inline_len = min_t(u64, isize, actual_end);
257         ret = insert_inline_extent(trans, root, inode, start,
258                                    inline_len, compressed_size,
259                                    compress_type, compressed_pages);
260         if (ret && ret != -ENOSPC) {
261                 btrfs_abort_transaction(trans, root, ret);
262                 return ret;
263         } else if (ret == -ENOSPC) {
264                 return 1;
265         }
266
267         btrfs_delalloc_release_metadata(inode, end + 1 - start);
268         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
269         return 0;
270 }
271
272 struct async_extent {
273         u64 start;
274         u64 ram_size;
275         u64 compressed_size;
276         struct page **pages;
277         unsigned long nr_pages;
278         int compress_type;
279         struct list_head list;
280 };
281
282 struct async_cow {
283         struct inode *inode;
284         struct btrfs_root *root;
285         struct page *locked_page;
286         u64 start;
287         u64 end;
288         struct list_head extents;
289         struct btrfs_work work;
290 };
291
292 static noinline int add_async_extent(struct async_cow *cow,
293                                      u64 start, u64 ram_size,
294                                      u64 compressed_size,
295                                      struct page **pages,
296                                      unsigned long nr_pages,
297                                      int compress_type)
298 {
299         struct async_extent *async_extent;
300
301         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
302         BUG_ON(!async_extent); /* -ENOMEM */
303         async_extent->start = start;
304         async_extent->ram_size = ram_size;
305         async_extent->compressed_size = compressed_size;
306         async_extent->pages = pages;
307         async_extent->nr_pages = nr_pages;
308         async_extent->compress_type = compress_type;
309         list_add_tail(&async_extent->list, &cow->extents);
310         return 0;
311 }
312
313 /*
314  * we create compressed extents in two phases.  The first
315  * phase compresses a range of pages that have already been
316  * locked (both pages and state bits are locked).
317  *
318  * This is done inside an ordered work queue, and the compression
319  * is spread across many cpus.  The actual IO submission is step
320  * two, and the ordered work queue takes care of making sure that
321  * happens in the same order things were put onto the queue by
322  * writepages and friends.
323  *
324  * If this code finds it can't get good compression, it puts an
325  * entry onto the work queue to write the uncompressed bytes.  This
326  * makes sure that both compressed inodes and uncompressed inodes
327  * are written in the same order that pdflush sent them down.
328  */
329 static noinline int compress_file_range(struct inode *inode,
330                                         struct page *locked_page,
331                                         u64 start, u64 end,
332                                         struct async_cow *async_cow,
333                                         int *num_added)
334 {
335         struct btrfs_root *root = BTRFS_I(inode)->root;
336         struct btrfs_trans_handle *trans;
337         u64 num_bytes;
338         u64 blocksize = root->sectorsize;
339         u64 actual_end;
340         u64 isize = i_size_read(inode);
341         int ret = 0;
342         struct page **pages = NULL;
343         unsigned long nr_pages;
344         unsigned long nr_pages_ret = 0;
345         unsigned long total_compressed = 0;
346         unsigned long total_in = 0;
347         unsigned long max_compressed = 128 * 1024;
348         unsigned long max_uncompressed = 128 * 1024;
349         int i;
350         int will_compress;
351         int compress_type = root->fs_info->compress_type;
352
353         /* if this is a small write inside eof, kick off a defrag */
354         if ((end - start + 1) < 16 * 1024 &&
355             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
356                 btrfs_add_inode_defrag(NULL, inode);
357
358         actual_end = min_t(u64, isize, end + 1);
359 again:
360         will_compress = 0;
361         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
362         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
363
364         /*
365          * we don't want to send crud past the end of i_size through
366          * compression, that's just a waste of CPU time.  So, if the
367          * end of the file is before the start of our current
368          * requested range of bytes, we bail out to the uncompressed
369          * cleanup code that can deal with all of this.
370          *
371          * It isn't really the fastest way to fix things, but this is a
372          * very uncommon corner.
373          */
374         if (actual_end <= start)
375                 goto cleanup_and_bail_uncompressed;
376
377         total_compressed = actual_end - start;
378
379         /* we want to make sure that amount of ram required to uncompress
380          * an extent is reasonable, so we limit the total size in ram
381          * of a compressed extent to 128k.  This is a crucial number
382          * because it also controls how easily we can spread reads across
383          * cpus for decompression.
384          *
385          * We also want to make sure the amount of IO required to do
386          * a random read is reasonably small, so we limit the size of
387          * a compressed extent to 128k.
388          */
389         total_compressed = min(total_compressed, max_uncompressed);
390         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
391         num_bytes = max(blocksize,  num_bytes);
392         total_in = 0;
393         ret = 0;
394
395         /*
396          * we do compression for mount -o compress and when the
397          * inode has not been flagged as nocompress.  This flag can
398          * change at any time if we discover bad compression ratios.
399          */
400         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS) &&
401             (btrfs_test_opt(root, COMPRESS) ||
402              (BTRFS_I(inode)->force_compress) ||
403              (BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))) {
404                 WARN_ON(pages);
405                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
406                 if (!pages) {
407                         /* just bail out to the uncompressed code */
408                         goto cont;
409                 }
410
411                 if (BTRFS_I(inode)->force_compress)
412                         compress_type = BTRFS_I(inode)->force_compress;
413
414                 ret = btrfs_compress_pages(compress_type,
415                                            inode->i_mapping, start,
416                                            total_compressed, pages,
417                                            nr_pages, &nr_pages_ret,
418                                            &total_in,
419                                            &total_compressed,
420                                            max_compressed);
421
422                 if (!ret) {
423                         unsigned long offset = total_compressed &
424                                 (PAGE_CACHE_SIZE - 1);
425                         struct page *page = pages[nr_pages_ret - 1];
426                         char *kaddr;
427
428                         /* zero the tail end of the last page, we might be
429                          * sending it down to disk
430                          */
431                         if (offset) {
432                                 kaddr = kmap_atomic(page);
433                                 memset(kaddr + offset, 0,
434                                        PAGE_CACHE_SIZE - offset);
435                                 kunmap_atomic(kaddr);
436                         }
437                         will_compress = 1;
438                 }
439         }
440 cont:
441         if (start == 0) {
442                 trans = btrfs_join_transaction(root);
443                 if (IS_ERR(trans)) {
444                         ret = PTR_ERR(trans);
445                         trans = NULL;
446                         goto cleanup_and_out;
447                 }
448                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
449
450                 /* lets try to make an inline extent */
451                 if (ret || total_in < (actual_end - start)) {
452                         /* we didn't compress the entire range, try
453                          * to make an uncompressed inline extent.
454                          */
455                         ret = cow_file_range_inline(trans, root, inode,
456                                                     start, end, 0, 0, NULL);
457                 } else {
458                         /* try making a compressed inline extent */
459                         ret = cow_file_range_inline(trans, root, inode,
460                                                     start, end,
461                                                     total_compressed,
462                                                     compress_type, pages);
463                 }
464                 if (ret <= 0) {
465                         /*
466                          * inline extent creation worked or returned error,
467                          * we don't need to create any more async work items.
468                          * Unlock and free up our temp pages.
469                          */
470                         extent_clear_unlock_delalloc(inode,
471                              &BTRFS_I(inode)->io_tree,
472                              start, end, NULL,
473                              EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
474                              EXTENT_CLEAR_DELALLOC |
475                              EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK);
476
477                         btrfs_end_transaction(trans, root);
478                         goto free_pages_out;
479                 }
480                 btrfs_end_transaction(trans, root);
481         }
482
483         if (will_compress) {
484                 /*
485                  * we aren't doing an inline extent round the compressed size
486                  * up to a block size boundary so the allocator does sane
487                  * things
488                  */
489                 total_compressed = (total_compressed + blocksize - 1) &
490                         ~(blocksize - 1);
491
492                 /*
493                  * one last check to make sure the compression is really a
494                  * win, compare the page count read with the blocks on disk
495                  */
496                 total_in = (total_in + PAGE_CACHE_SIZE - 1) &
497                         ~(PAGE_CACHE_SIZE - 1);
498                 if (total_compressed >= total_in) {
499                         will_compress = 0;
500                 } else {
501                         num_bytes = total_in;
502                 }
503         }
504         if (!will_compress && pages) {
505                 /*
506                  * the compression code ran but failed to make things smaller,
507                  * free any pages it allocated and our page pointer array
508                  */
509                 for (i = 0; i < nr_pages_ret; i++) {
510                         WARN_ON(pages[i]->mapping);
511                         page_cache_release(pages[i]);
512                 }
513                 kfree(pages);
514                 pages = NULL;
515                 total_compressed = 0;
516                 nr_pages_ret = 0;
517
518                 /* flag the file so we don't compress in the future */
519                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
520                     !(BTRFS_I(inode)->force_compress)) {
521                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
522                 }
523         }
524         if (will_compress) {
525                 *num_added += 1;
526
527                 /* the async work queues will take care of doing actual
528                  * allocation on disk for these compressed pages,
529                  * and will submit them to the elevator.
530                  */
531                 add_async_extent(async_cow, start, num_bytes,
532                                  total_compressed, pages, nr_pages_ret,
533                                  compress_type);
534
535                 if (start + num_bytes < end) {
536                         start += num_bytes;
537                         pages = NULL;
538                         cond_resched();
539                         goto again;
540                 }
541         } else {
542 cleanup_and_bail_uncompressed:
543                 /*
544                  * No compression, but we still need to write the pages in
545                  * the file we've been given so far.  redirty the locked
546                  * page if it corresponds to our extent and set things up
547                  * for the async work queue to run cow_file_range to do
548                  * the normal delalloc dance
549                  */
550                 if (page_offset(locked_page) >= start &&
551                     page_offset(locked_page) <= end) {
552                         __set_page_dirty_nobuffers(locked_page);
553                         /* unlocked later on in the async handlers */
554                 }
555                 add_async_extent(async_cow, start, end - start + 1,
556                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
557                 *num_added += 1;
558         }
559
560 out:
561         return ret;
562
563 free_pages_out:
564         for (i = 0; i < nr_pages_ret; i++) {
565                 WARN_ON(pages[i]->mapping);
566                 page_cache_release(pages[i]);
567         }
568         kfree(pages);
569
570         goto out;
571
572 cleanup_and_out:
573         extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
574                                      start, end, NULL,
575                                      EXTENT_CLEAR_UNLOCK_PAGE |
576                                      EXTENT_CLEAR_DIRTY |
577                                      EXTENT_CLEAR_DELALLOC |
578                                      EXTENT_SET_WRITEBACK |
579                                      EXTENT_END_WRITEBACK);
580         if (!trans || IS_ERR(trans))
581                 btrfs_error(root->fs_info, ret, "Failed to join transaction");
582         else
583                 btrfs_abort_transaction(trans, root, ret);
584         goto free_pages_out;
585 }
586
587 /*
588  * phase two of compressed writeback.  This is the ordered portion
589  * of the code, which only gets called in the order the work was
590  * queued.  We walk all the async extents created by compress_file_range
591  * and send them down to the disk.
592  */
593 static noinline int submit_compressed_extents(struct inode *inode,
594                                               struct async_cow *async_cow)
595 {
596         struct async_extent *async_extent;
597         u64 alloc_hint = 0;
598         struct btrfs_trans_handle *trans;
599         struct btrfs_key ins;
600         struct extent_map *em;
601         struct btrfs_root *root = BTRFS_I(inode)->root;
602         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
603         struct extent_io_tree *io_tree;
604         int ret = 0;
605
606         if (list_empty(&async_cow->extents))
607                 return 0;
608
609
610         while (!list_empty(&async_cow->extents)) {
611                 async_extent = list_entry(async_cow->extents.next,
612                                           struct async_extent, list);
613                 list_del(&async_extent->list);
614
615                 io_tree = &BTRFS_I(inode)->io_tree;
616
617 retry:
618                 /* did the compression code fall back to uncompressed IO? */
619                 if (!async_extent->pages) {
620                         int page_started = 0;
621                         unsigned long nr_written = 0;
622
623                         lock_extent(io_tree, async_extent->start,
624                                          async_extent->start +
625                                          async_extent->ram_size - 1);
626
627                         /* allocate blocks */
628                         ret = cow_file_range(inode, async_cow->locked_page,
629                                              async_extent->start,
630                                              async_extent->start +
631                                              async_extent->ram_size - 1,
632                                              &page_started, &nr_written, 0);
633
634                         /* JDM XXX */
635
636                         /*
637                          * if page_started, cow_file_range inserted an
638                          * inline extent and took care of all the unlocking
639                          * and IO for us.  Otherwise, we need to submit
640                          * all those pages down to the drive.
641                          */
642                         if (!page_started && !ret)
643                                 extent_write_locked_range(io_tree,
644                                                   inode, async_extent->start,
645                                                   async_extent->start +
646                                                   async_extent->ram_size - 1,
647                                                   btrfs_get_extent,
648                                                   WB_SYNC_ALL);
649                         kfree(async_extent);
650                         cond_resched();
651                         continue;
652                 }
653
654                 lock_extent(io_tree, async_extent->start,
655                             async_extent->start + async_extent->ram_size - 1);
656
657                 trans = btrfs_join_transaction(root);
658                 if (IS_ERR(trans)) {
659                         ret = PTR_ERR(trans);
660                 } else {
661                         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
662                         ret = btrfs_reserve_extent(trans, root,
663                                            async_extent->compressed_size,
664                                            async_extent->compressed_size,
665                                            0, alloc_hint, &ins, 1);
666                         if (ret)
667                                 btrfs_abort_transaction(trans, root, ret);
668                         btrfs_end_transaction(trans, root);
669                 }
670
671                 if (ret) {
672                         int i;
673                         for (i = 0; i < async_extent->nr_pages; i++) {
674                                 WARN_ON(async_extent->pages[i]->mapping);
675                                 page_cache_release(async_extent->pages[i]);
676                         }
677                         kfree(async_extent->pages);
678                         async_extent->nr_pages = 0;
679                         async_extent->pages = NULL;
680                         unlock_extent(io_tree, async_extent->start,
681                                       async_extent->start +
682                                       async_extent->ram_size - 1);
683                         if (ret == -ENOSPC)
684                                 goto retry;
685                         goto out_free; /* JDM: Requeue? */
686                 }
687
688                 /*
689                  * here we're doing allocation and writeback of the
690                  * compressed pages
691                  */
692                 btrfs_drop_extent_cache(inode, async_extent->start,
693                                         async_extent->start +
694                                         async_extent->ram_size - 1, 0);
695
696                 em = alloc_extent_map();
697                 BUG_ON(!em); /* -ENOMEM */
698                 em->start = async_extent->start;
699                 em->len = async_extent->ram_size;
700                 em->orig_start = em->start;
701
702                 em->block_start = ins.objectid;
703                 em->block_len = ins.offset;
704                 em->bdev = root->fs_info->fs_devices->latest_bdev;
705                 em->compress_type = async_extent->compress_type;
706                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
707                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
708
709                 while (1) {
710                         write_lock(&em_tree->lock);
711                         ret = add_extent_mapping(em_tree, em);
712                         write_unlock(&em_tree->lock);
713                         if (ret != -EEXIST) {
714                                 free_extent_map(em);
715                                 break;
716                         }
717                         btrfs_drop_extent_cache(inode, async_extent->start,
718                                                 async_extent->start +
719                                                 async_extent->ram_size - 1, 0);
720                 }
721
722                 ret = btrfs_add_ordered_extent_compress(inode,
723                                                 async_extent->start,
724                                                 ins.objectid,
725                                                 async_extent->ram_size,
726                                                 ins.offset,
727                                                 BTRFS_ORDERED_COMPRESSED,
728                                                 async_extent->compress_type);
729                 BUG_ON(ret); /* -ENOMEM */
730
731                 /*
732                  * clear dirty, set writeback and unlock the pages.
733                  */
734                 extent_clear_unlock_delalloc(inode,
735                                 &BTRFS_I(inode)->io_tree,
736                                 async_extent->start,
737                                 async_extent->start +
738                                 async_extent->ram_size - 1,
739                                 NULL, EXTENT_CLEAR_UNLOCK_PAGE |
740                                 EXTENT_CLEAR_UNLOCK |
741                                 EXTENT_CLEAR_DELALLOC |
742                                 EXTENT_CLEAR_DIRTY | EXTENT_SET_WRITEBACK);
743
744                 ret = btrfs_submit_compressed_write(inode,
745                                     async_extent->start,
746                                     async_extent->ram_size,
747                                     ins.objectid,
748                                     ins.offset, async_extent->pages,
749                                     async_extent->nr_pages);
750
751                 BUG_ON(ret); /* -ENOMEM */
752                 alloc_hint = ins.objectid + ins.offset;
753                 kfree(async_extent);
754                 cond_resched();
755         }
756         ret = 0;
757 out:
758         return ret;
759 out_free:
760         kfree(async_extent);
761         goto out;
762 }
763
764 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
765                                       u64 num_bytes)
766 {
767         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
768         struct extent_map *em;
769         u64 alloc_hint = 0;
770
771         read_lock(&em_tree->lock);
772         em = search_extent_mapping(em_tree, start, num_bytes);
773         if (em) {
774                 /*
775                  * if block start isn't an actual block number then find the
776                  * first block in this inode and use that as a hint.  If that
777                  * block is also bogus then just don't worry about it.
778                  */
779                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
780                         free_extent_map(em);
781                         em = search_extent_mapping(em_tree, 0, 0);
782                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
783                                 alloc_hint = em->block_start;
784                         if (em)
785                                 free_extent_map(em);
786                 } else {
787                         alloc_hint = em->block_start;
788                         free_extent_map(em);
789                 }
790         }
791         read_unlock(&em_tree->lock);
792
793         return alloc_hint;
794 }
795
796 /*
797  * when extent_io.c finds a delayed allocation range in the file,
798  * the call backs end up in this code.  The basic idea is to
799  * allocate extents on disk for the range, and create ordered data structs
800  * in ram to track those extents.
801  *
802  * locked_page is the page that writepage had locked already.  We use
803  * it to make sure we don't do extra locks or unlocks.
804  *
805  * *page_started is set to one if we unlock locked_page and do everything
806  * required to start IO on it.  It may be clean and already done with
807  * IO when we return.
808  */
809 static noinline int cow_file_range(struct inode *inode,
810                                    struct page *locked_page,
811                                    u64 start, u64 end, int *page_started,
812                                    unsigned long *nr_written,
813                                    int unlock)
814 {
815         struct btrfs_root *root = BTRFS_I(inode)->root;
816         struct btrfs_trans_handle *trans;
817         u64 alloc_hint = 0;
818         u64 num_bytes;
819         unsigned long ram_size;
820         u64 disk_num_bytes;
821         u64 cur_alloc_size;
822         u64 blocksize = root->sectorsize;
823         struct btrfs_key ins;
824         struct extent_map *em;
825         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
826         int ret = 0;
827
828         BUG_ON(btrfs_is_free_space_inode(inode));
829         trans = btrfs_join_transaction(root);
830         if (IS_ERR(trans)) {
831                 extent_clear_unlock_delalloc(inode,
832                              &BTRFS_I(inode)->io_tree,
833                              start, end, locked_page,
834                              EXTENT_CLEAR_UNLOCK_PAGE |
835                              EXTENT_CLEAR_UNLOCK |
836                              EXTENT_CLEAR_DELALLOC |
837                              EXTENT_CLEAR_DIRTY |
838                              EXTENT_SET_WRITEBACK |
839                              EXTENT_END_WRITEBACK);
840                 return PTR_ERR(trans);
841         }
842         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
843
844         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
845         num_bytes = max(blocksize,  num_bytes);
846         disk_num_bytes = num_bytes;
847         ret = 0;
848
849         /* if this is a small write inside eof, kick off defrag */
850         if (num_bytes < 64 * 1024 &&
851             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
852                 btrfs_add_inode_defrag(trans, inode);
853
854         if (start == 0) {
855                 /* lets try to make an inline extent */
856                 ret = cow_file_range_inline(trans, root, inode,
857                                             start, end, 0, 0, NULL);
858                 if (ret == 0) {
859                         extent_clear_unlock_delalloc(inode,
860                                      &BTRFS_I(inode)->io_tree,
861                                      start, end, NULL,
862                                      EXTENT_CLEAR_UNLOCK_PAGE |
863                                      EXTENT_CLEAR_UNLOCK |
864                                      EXTENT_CLEAR_DELALLOC |
865                                      EXTENT_CLEAR_DIRTY |
866                                      EXTENT_SET_WRITEBACK |
867                                      EXTENT_END_WRITEBACK);
868
869                         *nr_written = *nr_written +
870                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
871                         *page_started = 1;
872                         goto out;
873                 } else if (ret < 0) {
874                         btrfs_abort_transaction(trans, root, ret);
875                         goto out_unlock;
876                 }
877         }
878
879         BUG_ON(disk_num_bytes >
880                btrfs_super_total_bytes(root->fs_info->super_copy));
881
882         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
883         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
884
885         while (disk_num_bytes > 0) {
886                 unsigned long op;
887
888                 cur_alloc_size = disk_num_bytes;
889                 ret = btrfs_reserve_extent(trans, root, cur_alloc_size,
890                                            root->sectorsize, 0, alloc_hint,
891                                            &ins, 1);
892                 if (ret < 0) {
893                         btrfs_abort_transaction(trans, root, ret);
894                         goto out_unlock;
895                 }
896
897                 em = alloc_extent_map();
898                 BUG_ON(!em); /* -ENOMEM */
899                 em->start = start;
900                 em->orig_start = em->start;
901                 ram_size = ins.offset;
902                 em->len = ins.offset;
903
904                 em->block_start = ins.objectid;
905                 em->block_len = ins.offset;
906                 em->bdev = root->fs_info->fs_devices->latest_bdev;
907                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
908
909                 while (1) {
910                         write_lock(&em_tree->lock);
911                         ret = add_extent_mapping(em_tree, em);
912                         write_unlock(&em_tree->lock);
913                         if (ret != -EEXIST) {
914                                 free_extent_map(em);
915                                 break;
916                         }
917                         btrfs_drop_extent_cache(inode, start,
918                                                 start + ram_size - 1, 0);
919                 }
920
921                 cur_alloc_size = ins.offset;
922                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
923                                                ram_size, cur_alloc_size, 0);
924                 BUG_ON(ret); /* -ENOMEM */
925
926                 if (root->root_key.objectid ==
927                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
928                         ret = btrfs_reloc_clone_csums(inode, start,
929                                                       cur_alloc_size);
930                         if (ret) {
931                                 btrfs_abort_transaction(trans, root, ret);
932                                 goto out_unlock;
933                         }
934                 }
935
936                 if (disk_num_bytes < cur_alloc_size)
937                         break;
938
939                 /* we're not doing compressed IO, don't unlock the first
940                  * page (which the caller expects to stay locked), don't
941                  * clear any dirty bits and don't set any writeback bits
942                  *
943                  * Do set the Private2 bit so we know this page was properly
944                  * setup for writepage
945                  */
946                 op = unlock ? EXTENT_CLEAR_UNLOCK_PAGE : 0;
947                 op |= EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
948                         EXTENT_SET_PRIVATE2;
949
950                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
951                                              start, start + ram_size - 1,
952                                              locked_page, op);
953                 disk_num_bytes -= cur_alloc_size;
954                 num_bytes -= cur_alloc_size;
955                 alloc_hint = ins.objectid + ins.offset;
956                 start += cur_alloc_size;
957         }
958         ret = 0;
959 out:
960         btrfs_end_transaction(trans, root);
961
962         return ret;
963 out_unlock:
964         extent_clear_unlock_delalloc(inode,
965                      &BTRFS_I(inode)->io_tree,
966                      start, end, locked_page,
967                      EXTENT_CLEAR_UNLOCK_PAGE |
968                      EXTENT_CLEAR_UNLOCK |
969                      EXTENT_CLEAR_DELALLOC |
970                      EXTENT_CLEAR_DIRTY |
971                      EXTENT_SET_WRITEBACK |
972                      EXTENT_END_WRITEBACK);
973
974         goto out;
975 }
976
977 /*
978  * work queue call back to started compression on a file and pages
979  */
980 static noinline void async_cow_start(struct btrfs_work *work)
981 {
982         struct async_cow *async_cow;
983         int num_added = 0;
984         async_cow = container_of(work, struct async_cow, work);
985
986         compress_file_range(async_cow->inode, async_cow->locked_page,
987                             async_cow->start, async_cow->end, async_cow,
988                             &num_added);
989         if (num_added == 0) {
990                 btrfs_add_delayed_iput(async_cow->inode);
991                 async_cow->inode = NULL;
992         }
993 }
994
995 /*
996  * work queue call back to submit previously compressed pages
997  */
998 static noinline void async_cow_submit(struct btrfs_work *work)
999 {
1000         struct async_cow *async_cow;
1001         struct btrfs_root *root;
1002         unsigned long nr_pages;
1003
1004         async_cow = container_of(work, struct async_cow, work);
1005
1006         root = async_cow->root;
1007         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
1008                 PAGE_CACHE_SHIFT;
1009
1010         atomic_sub(nr_pages, &root->fs_info->async_delalloc_pages);
1011
1012         if (atomic_read(&root->fs_info->async_delalloc_pages) <
1013             5 * 1024 * 1024 &&
1014             waitqueue_active(&root->fs_info->async_submit_wait))
1015                 wake_up(&root->fs_info->async_submit_wait);
1016
1017         if (async_cow->inode)
1018                 submit_compressed_extents(async_cow->inode, async_cow);
1019 }
1020
1021 static noinline void async_cow_free(struct btrfs_work *work)
1022 {
1023         struct async_cow *async_cow;
1024         async_cow = container_of(work, struct async_cow, work);
1025         if (async_cow->inode)
1026                 btrfs_add_delayed_iput(async_cow->inode);
1027         kfree(async_cow);
1028 }
1029
1030 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1031                                 u64 start, u64 end, int *page_started,
1032                                 unsigned long *nr_written)
1033 {
1034         struct async_cow *async_cow;
1035         struct btrfs_root *root = BTRFS_I(inode)->root;
1036         unsigned long nr_pages;
1037         u64 cur_end;
1038         int limit = 10 * 1024 * 1024;
1039
1040         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1041                          1, 0, NULL, GFP_NOFS);
1042         while (start < end) {
1043                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1044                 BUG_ON(!async_cow); /* -ENOMEM */
1045                 async_cow->inode = igrab(inode);
1046                 async_cow->root = root;
1047                 async_cow->locked_page = locked_page;
1048                 async_cow->start = start;
1049
1050                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
1051                         cur_end = end;
1052                 else
1053                         cur_end = min(end, start + 512 * 1024 - 1);
1054
1055                 async_cow->end = cur_end;
1056                 INIT_LIST_HEAD(&async_cow->extents);
1057
1058                 async_cow->work.func = async_cow_start;
1059                 async_cow->work.ordered_func = async_cow_submit;
1060                 async_cow->work.ordered_free = async_cow_free;
1061                 async_cow->work.flags = 0;
1062
1063                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
1064                         PAGE_CACHE_SHIFT;
1065                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
1066
1067                 btrfs_queue_worker(&root->fs_info->delalloc_workers,
1068                                    &async_cow->work);
1069
1070                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
1071                         wait_event(root->fs_info->async_submit_wait,
1072                            (atomic_read(&root->fs_info->async_delalloc_pages) <
1073                             limit));
1074                 }
1075
1076                 while (atomic_read(&root->fs_info->async_submit_draining) &&
1077                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1078                         wait_event(root->fs_info->async_submit_wait,
1079                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
1080                            0));
1081                 }
1082
1083                 *nr_written += nr_pages;
1084                 start = cur_end + 1;
1085         }
1086         *page_started = 1;
1087         return 0;
1088 }
1089
1090 static noinline int csum_exist_in_range(struct btrfs_root *root,
1091                                         u64 bytenr, u64 num_bytes)
1092 {
1093         int ret;
1094         struct btrfs_ordered_sum *sums;
1095         LIST_HEAD(list);
1096
1097         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1098                                        bytenr + num_bytes - 1, &list, 0);
1099         if (ret == 0 && list_empty(&list))
1100                 return 0;
1101
1102         while (!list_empty(&list)) {
1103                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1104                 list_del(&sums->list);
1105                 kfree(sums);
1106         }
1107         return 1;
1108 }
1109
1110 /*
1111  * when nowcow writeback call back.  This checks for snapshots or COW copies
1112  * of the extents that exist in the file, and COWs the file as required.
1113  *
1114  * If no cow copies or snapshots exist, we write directly to the existing
1115  * blocks on disk
1116  */
1117 static noinline int run_delalloc_nocow(struct inode *inode,
1118                                        struct page *locked_page,
1119                               u64 start, u64 end, int *page_started, int force,
1120                               unsigned long *nr_written)
1121 {
1122         struct btrfs_root *root = BTRFS_I(inode)->root;
1123         struct btrfs_trans_handle *trans;
1124         struct extent_buffer *leaf;
1125         struct btrfs_path *path;
1126         struct btrfs_file_extent_item *fi;
1127         struct btrfs_key found_key;
1128         u64 cow_start;
1129         u64 cur_offset;
1130         u64 extent_end;
1131         u64 extent_offset;
1132         u64 disk_bytenr;
1133         u64 num_bytes;
1134         int extent_type;
1135         int ret, err;
1136         int type;
1137         int nocow;
1138         int check_prev = 1;
1139         bool nolock;
1140         u64 ino = btrfs_ino(inode);
1141
1142         path = btrfs_alloc_path();
1143         if (!path) {
1144                 extent_clear_unlock_delalloc(inode,
1145                              &BTRFS_I(inode)->io_tree,
1146                              start, end, locked_page,
1147                              EXTENT_CLEAR_UNLOCK_PAGE |
1148                              EXTENT_CLEAR_UNLOCK |
1149                              EXTENT_CLEAR_DELALLOC |
1150                              EXTENT_CLEAR_DIRTY |
1151                              EXTENT_SET_WRITEBACK |
1152                              EXTENT_END_WRITEBACK);
1153                 return -ENOMEM;
1154         }
1155
1156         nolock = btrfs_is_free_space_inode(inode);
1157
1158         if (nolock)
1159                 trans = btrfs_join_transaction_nolock(root);
1160         else
1161                 trans = btrfs_join_transaction(root);
1162
1163         if (IS_ERR(trans)) {
1164                 extent_clear_unlock_delalloc(inode,
1165                              &BTRFS_I(inode)->io_tree,
1166                              start, end, locked_page,
1167                              EXTENT_CLEAR_UNLOCK_PAGE |
1168                              EXTENT_CLEAR_UNLOCK |
1169                              EXTENT_CLEAR_DELALLOC |
1170                              EXTENT_CLEAR_DIRTY |
1171                              EXTENT_SET_WRITEBACK |
1172                              EXTENT_END_WRITEBACK);
1173                 btrfs_free_path(path);
1174                 return PTR_ERR(trans);
1175         }
1176
1177         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1178
1179         cow_start = (u64)-1;
1180         cur_offset = start;
1181         while (1) {
1182                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1183                                                cur_offset, 0);
1184                 if (ret < 0) {
1185                         btrfs_abort_transaction(trans, root, ret);
1186                         goto error;
1187                 }
1188                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1189                         leaf = path->nodes[0];
1190                         btrfs_item_key_to_cpu(leaf, &found_key,
1191                                               path->slots[0] - 1);
1192                         if (found_key.objectid == ino &&
1193                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1194                                 path->slots[0]--;
1195                 }
1196                 check_prev = 0;
1197 next_slot:
1198                 leaf = path->nodes[0];
1199                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1200                         ret = btrfs_next_leaf(root, path);
1201                         if (ret < 0) {
1202                                 btrfs_abort_transaction(trans, root, ret);
1203                                 goto error;
1204                         }
1205                         if (ret > 0)
1206                                 break;
1207                         leaf = path->nodes[0];
1208                 }
1209
1210                 nocow = 0;
1211                 disk_bytenr = 0;
1212                 num_bytes = 0;
1213                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1214
1215                 if (found_key.objectid > ino ||
1216                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1217                     found_key.offset > end)
1218                         break;
1219
1220                 if (found_key.offset > cur_offset) {
1221                         extent_end = found_key.offset;
1222                         extent_type = 0;
1223                         goto out_check;
1224                 }
1225
1226                 fi = btrfs_item_ptr(leaf, path->slots[0],
1227                                     struct btrfs_file_extent_item);
1228                 extent_type = btrfs_file_extent_type(leaf, fi);
1229
1230                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1231                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1232                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1233                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1234                         extent_end = found_key.offset +
1235                                 btrfs_file_extent_num_bytes(leaf, fi);
1236                         if (extent_end <= start) {
1237                                 path->slots[0]++;
1238                                 goto next_slot;
1239                         }
1240                         if (disk_bytenr == 0)
1241                                 goto out_check;
1242                         if (btrfs_file_extent_compression(leaf, fi) ||
1243                             btrfs_file_extent_encryption(leaf, fi) ||
1244                             btrfs_file_extent_other_encoding(leaf, fi))
1245                                 goto out_check;
1246                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1247                                 goto out_check;
1248                         if (btrfs_extent_readonly(root, disk_bytenr))
1249                                 goto out_check;
1250                         if (btrfs_cross_ref_exist(trans, root, ino,
1251                                                   found_key.offset -
1252                                                   extent_offset, disk_bytenr))
1253                                 goto out_check;
1254                         disk_bytenr += extent_offset;
1255                         disk_bytenr += cur_offset - found_key.offset;
1256                         num_bytes = min(end + 1, extent_end) - cur_offset;
1257                         /*
1258                          * force cow if csum exists in the range.
1259                          * this ensure that csum for a given extent are
1260                          * either valid or do not exist.
1261                          */
1262                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1263                                 goto out_check;
1264                         nocow = 1;
1265                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1266                         extent_end = found_key.offset +
1267                                 btrfs_file_extent_inline_len(leaf, fi);
1268                         extent_end = ALIGN(extent_end, root->sectorsize);
1269                 } else {
1270                         BUG_ON(1);
1271                 }
1272 out_check:
1273                 if (extent_end <= start) {
1274                         path->slots[0]++;
1275                         goto next_slot;
1276                 }
1277                 if (!nocow) {
1278                         if (cow_start == (u64)-1)
1279                                 cow_start = cur_offset;
1280                         cur_offset = extent_end;
1281                         if (cur_offset > end)
1282                                 break;
1283                         path->slots[0]++;
1284                         goto next_slot;
1285                 }
1286
1287                 btrfs_release_path(path);
1288                 if (cow_start != (u64)-1) {
1289                         ret = cow_file_range(inode, locked_page, cow_start,
1290                                         found_key.offset - 1, page_started,
1291                                         nr_written, 1);
1292                         if (ret) {
1293                                 btrfs_abort_transaction(trans, root, ret);
1294                                 goto error;
1295                         }
1296                         cow_start = (u64)-1;
1297                 }
1298
1299                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1300                         struct extent_map *em;
1301                         struct extent_map_tree *em_tree;
1302                         em_tree = &BTRFS_I(inode)->extent_tree;
1303                         em = alloc_extent_map();
1304                         BUG_ON(!em); /* -ENOMEM */
1305                         em->start = cur_offset;
1306                         em->orig_start = em->start;
1307                         em->len = num_bytes;
1308                         em->block_len = num_bytes;
1309                         em->block_start = disk_bytenr;
1310                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1311                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1312                         while (1) {
1313                                 write_lock(&em_tree->lock);
1314                                 ret = add_extent_mapping(em_tree, em);
1315                                 write_unlock(&em_tree->lock);
1316                                 if (ret != -EEXIST) {
1317                                         free_extent_map(em);
1318                                         break;
1319                                 }
1320                                 btrfs_drop_extent_cache(inode, em->start,
1321                                                 em->start + em->len - 1, 0);
1322                         }
1323                         type = BTRFS_ORDERED_PREALLOC;
1324                 } else {
1325                         type = BTRFS_ORDERED_NOCOW;
1326                 }
1327
1328                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1329                                                num_bytes, num_bytes, type);
1330                 BUG_ON(ret); /* -ENOMEM */
1331
1332                 if (root->root_key.objectid ==
1333                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1334                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1335                                                       num_bytes);
1336                         if (ret) {
1337                                 btrfs_abort_transaction(trans, root, ret);
1338                                 goto error;
1339                         }
1340                 }
1341
1342                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
1343                                 cur_offset, cur_offset + num_bytes - 1,
1344                                 locked_page, EXTENT_CLEAR_UNLOCK_PAGE |
1345                                 EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
1346                                 EXTENT_SET_PRIVATE2);
1347                 cur_offset = extent_end;
1348                 if (cur_offset > end)
1349                         break;
1350         }
1351         btrfs_release_path(path);
1352
1353         if (cur_offset <= end && cow_start == (u64)-1) {
1354                 cow_start = cur_offset;
1355                 cur_offset = end;
1356         }
1357
1358         if (cow_start != (u64)-1) {
1359                 ret = cow_file_range(inode, locked_page, cow_start, end,
1360                                      page_started, nr_written, 1);
1361                 if (ret) {
1362                         btrfs_abort_transaction(trans, root, ret);
1363                         goto error;
1364                 }
1365         }
1366
1367 error:
1368         if (nolock) {
1369                 err = btrfs_end_transaction_nolock(trans, root);
1370         } else {
1371                 err = btrfs_end_transaction(trans, root);
1372         }
1373         if (!ret)
1374                 ret = err;
1375
1376         if (ret && cur_offset < end)
1377                 extent_clear_unlock_delalloc(inode,
1378                              &BTRFS_I(inode)->io_tree,
1379                              cur_offset, end, locked_page,
1380                              EXTENT_CLEAR_UNLOCK_PAGE |
1381                              EXTENT_CLEAR_UNLOCK |
1382                              EXTENT_CLEAR_DELALLOC |
1383                              EXTENT_CLEAR_DIRTY |
1384                              EXTENT_SET_WRITEBACK |
1385                              EXTENT_END_WRITEBACK);
1386
1387         btrfs_free_path(path);
1388         return ret;
1389 }
1390
1391 /*
1392  * extent_io.c call back to do delayed allocation processing
1393  */
1394 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1395                               u64 start, u64 end, int *page_started,
1396                               unsigned long *nr_written)
1397 {
1398         int ret;
1399         struct btrfs_root *root = BTRFS_I(inode)->root;
1400
1401         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) {
1402                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1403                                          page_started, 1, nr_written);
1404         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC) {
1405                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1406                                          page_started, 0, nr_written);
1407         } else if (!btrfs_test_opt(root, COMPRESS) &&
1408                    !(BTRFS_I(inode)->force_compress) &&
1409                    !(BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS)) {
1410                 ret = cow_file_range(inode, locked_page, start, end,
1411                                       page_started, nr_written, 1);
1412         } else {
1413                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1414                         &BTRFS_I(inode)->runtime_flags);
1415                 ret = cow_file_range_async(inode, locked_page, start, end,
1416                                            page_started, nr_written);
1417         }
1418         return ret;
1419 }
1420
1421 static void btrfs_split_extent_hook(struct inode *inode,
1422                                     struct extent_state *orig, u64 split)
1423 {
1424         /* not delalloc, ignore it */
1425         if (!(orig->state & EXTENT_DELALLOC))
1426                 return;
1427
1428         spin_lock(&BTRFS_I(inode)->lock);
1429         BTRFS_I(inode)->outstanding_extents++;
1430         spin_unlock(&BTRFS_I(inode)->lock);
1431 }
1432
1433 /*
1434  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1435  * extents so we can keep track of new extents that are just merged onto old
1436  * extents, such as when we are doing sequential writes, so we can properly
1437  * account for the metadata space we'll need.
1438  */
1439 static void btrfs_merge_extent_hook(struct inode *inode,
1440                                     struct extent_state *new,
1441                                     struct extent_state *other)
1442 {
1443         /* not delalloc, ignore it */
1444         if (!(other->state & EXTENT_DELALLOC))
1445                 return;
1446
1447         spin_lock(&BTRFS_I(inode)->lock);
1448         BTRFS_I(inode)->outstanding_extents--;
1449         spin_unlock(&BTRFS_I(inode)->lock);
1450 }
1451
1452 /*
1453  * extent_io.c set_bit_hook, used to track delayed allocation
1454  * bytes in this file, and to maintain the list of inodes that
1455  * have pending delalloc work to be done.
1456  */
1457 static void btrfs_set_bit_hook(struct inode *inode,
1458                                struct extent_state *state, int *bits)
1459 {
1460
1461         /*
1462          * set_bit and clear bit hooks normally require _irqsave/restore
1463          * but in this case, we are only testing for the DELALLOC
1464          * bit, which is only set or cleared with irqs on
1465          */
1466         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1467                 struct btrfs_root *root = BTRFS_I(inode)->root;
1468                 u64 len = state->end + 1 - state->start;
1469                 bool do_list = !btrfs_is_free_space_inode(inode);
1470
1471                 if (*bits & EXTENT_FIRST_DELALLOC) {
1472                         *bits &= ~EXTENT_FIRST_DELALLOC;
1473                 } else {
1474                         spin_lock(&BTRFS_I(inode)->lock);
1475                         BTRFS_I(inode)->outstanding_extents++;
1476                         spin_unlock(&BTRFS_I(inode)->lock);
1477                 }
1478
1479                 spin_lock(&root->fs_info->delalloc_lock);
1480                 BTRFS_I(inode)->delalloc_bytes += len;
1481                 root->fs_info->delalloc_bytes += len;
1482                 if (do_list && list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1483                         list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1484                                       &root->fs_info->delalloc_inodes);
1485                 }
1486                 spin_unlock(&root->fs_info->delalloc_lock);
1487         }
1488 }
1489
1490 /*
1491  * extent_io.c clear_bit_hook, see set_bit_hook for why
1492  */
1493 static void btrfs_clear_bit_hook(struct inode *inode,
1494                                  struct extent_state *state, int *bits)
1495 {
1496         /*
1497          * set_bit and clear bit hooks normally require _irqsave/restore
1498          * but in this case, we are only testing for the DELALLOC
1499          * bit, which is only set or cleared with irqs on
1500          */
1501         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1502                 struct btrfs_root *root = BTRFS_I(inode)->root;
1503                 u64 len = state->end + 1 - state->start;
1504                 bool do_list = !btrfs_is_free_space_inode(inode);
1505
1506                 if (*bits & EXTENT_FIRST_DELALLOC) {
1507                         *bits &= ~EXTENT_FIRST_DELALLOC;
1508                 } else if (!(*bits & EXTENT_DO_ACCOUNTING)) {
1509                         spin_lock(&BTRFS_I(inode)->lock);
1510                         BTRFS_I(inode)->outstanding_extents--;
1511                         spin_unlock(&BTRFS_I(inode)->lock);
1512                 }
1513
1514                 if (*bits & EXTENT_DO_ACCOUNTING)
1515                         btrfs_delalloc_release_metadata(inode, len);
1516
1517                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1518                     && do_list)
1519                         btrfs_free_reserved_data_space(inode, len);
1520
1521                 spin_lock(&root->fs_info->delalloc_lock);
1522                 root->fs_info->delalloc_bytes -= len;
1523                 BTRFS_I(inode)->delalloc_bytes -= len;
1524
1525                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1526                     !list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1527                         list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1528                 }
1529                 spin_unlock(&root->fs_info->delalloc_lock);
1530         }
1531 }
1532
1533 /*
1534  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1535  * we don't create bios that span stripes or chunks
1536  */
1537 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1538                          size_t size, struct bio *bio,
1539                          unsigned long bio_flags)
1540 {
1541         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1542         struct btrfs_mapping_tree *map_tree;
1543         u64 logical = (u64)bio->bi_sector << 9;
1544         u64 length = 0;
1545         u64 map_length;
1546         int ret;
1547
1548         if (bio_flags & EXTENT_BIO_COMPRESSED)
1549                 return 0;
1550
1551         length = bio->bi_size;
1552         map_tree = &root->fs_info->mapping_tree;
1553         map_length = length;
1554         ret = btrfs_map_block(map_tree, READ, logical,
1555                               &map_length, NULL, 0);
1556         /* Will always return 0 or 1 with map_multi == NULL */
1557         BUG_ON(ret < 0);
1558         if (map_length < length + size)
1559                 return 1;
1560         return 0;
1561 }
1562
1563 /*
1564  * in order to insert checksums into the metadata in large chunks,
1565  * we wait until bio submission time.   All the pages in the bio are
1566  * checksummed and sums are attached onto the ordered extent record.
1567  *
1568  * At IO completion time the cums attached on the ordered extent record
1569  * are inserted into the btree
1570  */
1571 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1572                                     struct bio *bio, int mirror_num,
1573                                     unsigned long bio_flags,
1574                                     u64 bio_offset)
1575 {
1576         struct btrfs_root *root = BTRFS_I(inode)->root;
1577         int ret = 0;
1578
1579         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1580         BUG_ON(ret); /* -ENOMEM */
1581         return 0;
1582 }
1583
1584 /*
1585  * in order to insert checksums into the metadata in large chunks,
1586  * we wait until bio submission time.   All the pages in the bio are
1587  * checksummed and sums are attached onto the ordered extent record.
1588  *
1589  * At IO completion time the cums attached on the ordered extent record
1590  * are inserted into the btree
1591  */
1592 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1593                           int mirror_num, unsigned long bio_flags,
1594                           u64 bio_offset)
1595 {
1596         struct btrfs_root *root = BTRFS_I(inode)->root;
1597         return btrfs_map_bio(root, rw, bio, mirror_num, 1);
1598 }
1599
1600 /*
1601  * extent_io.c submission hook. This does the right thing for csum calculation
1602  * on write, or reading the csums from the tree before a read
1603  */
1604 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1605                           int mirror_num, unsigned long bio_flags,
1606                           u64 bio_offset)
1607 {
1608         struct btrfs_root *root = BTRFS_I(inode)->root;
1609         int ret = 0;
1610         int skip_sum;
1611         int metadata = 0;
1612
1613         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1614
1615         if (btrfs_is_free_space_inode(inode))
1616                 metadata = 2;
1617
1618         if (!(rw & REQ_WRITE)) {
1619                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, metadata);
1620                 if (ret)
1621                         return ret;
1622
1623                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1624                         return btrfs_submit_compressed_read(inode, bio,
1625                                                     mirror_num, bio_flags);
1626                 } else if (!skip_sum) {
1627                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1628                         if (ret)
1629                                 return ret;
1630                 }
1631                 goto mapit;
1632         } else if (!skip_sum) {
1633                 /* csum items have already been cloned */
1634                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1635                         goto mapit;
1636                 /* we're doing a write, do the async checksumming */
1637                 return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1638                                    inode, rw, bio, mirror_num,
1639                                    bio_flags, bio_offset,
1640                                    __btrfs_submit_bio_start,
1641                                    __btrfs_submit_bio_done);
1642         }
1643
1644 mapit:
1645         return btrfs_map_bio(root, rw, bio, mirror_num, 0);
1646 }
1647
1648 /*
1649  * given a list of ordered sums record them in the inode.  This happens
1650  * at IO completion time based on sums calculated at bio submission time.
1651  */
1652 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1653                              struct inode *inode, u64 file_offset,
1654                              struct list_head *list)
1655 {
1656         struct btrfs_ordered_sum *sum;
1657
1658         list_for_each_entry(sum, list, list) {
1659                 btrfs_csum_file_blocks(trans,
1660                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1661         }
1662         return 0;
1663 }
1664
1665 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1666                               struct extent_state **cached_state)
1667 {
1668         if ((end & (PAGE_CACHE_SIZE - 1)) == 0)
1669                 WARN_ON(1);
1670         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1671                                    cached_state, GFP_NOFS);
1672 }
1673
1674 /* see btrfs_writepage_start_hook for details on why this is required */
1675 struct btrfs_writepage_fixup {
1676         struct page *page;
1677         struct btrfs_work work;
1678 };
1679
1680 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1681 {
1682         struct btrfs_writepage_fixup *fixup;
1683         struct btrfs_ordered_extent *ordered;
1684         struct extent_state *cached_state = NULL;
1685         struct page *page;
1686         struct inode *inode;
1687         u64 page_start;
1688         u64 page_end;
1689         int ret;
1690
1691         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1692         page = fixup->page;
1693 again:
1694         lock_page(page);
1695         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1696                 ClearPageChecked(page);
1697                 goto out_page;
1698         }
1699
1700         inode = page->mapping->host;
1701         page_start = page_offset(page);
1702         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1703
1704         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1705                          &cached_state);
1706
1707         /* already ordered? We're done */
1708         if (PagePrivate2(page))
1709                 goto out;
1710
1711         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1712         if (ordered) {
1713                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1714                                      page_end, &cached_state, GFP_NOFS);
1715                 unlock_page(page);
1716                 btrfs_start_ordered_extent(inode, ordered, 1);
1717                 btrfs_put_ordered_extent(ordered);
1718                 goto again;
1719         }
1720
1721         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
1722         if (ret) {
1723                 mapping_set_error(page->mapping, ret);
1724                 end_extent_writepage(page, ret, page_start, page_end);
1725                 ClearPageChecked(page);
1726                 goto out;
1727          }
1728
1729         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
1730         ClearPageChecked(page);
1731         set_page_dirty(page);
1732 out:
1733         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1734                              &cached_state, GFP_NOFS);
1735 out_page:
1736         unlock_page(page);
1737         page_cache_release(page);
1738         kfree(fixup);
1739 }
1740
1741 /*
1742  * There are a few paths in the higher layers of the kernel that directly
1743  * set the page dirty bit without asking the filesystem if it is a
1744  * good idea.  This causes problems because we want to make sure COW
1745  * properly happens and the data=ordered rules are followed.
1746  *
1747  * In our case any range that doesn't have the ORDERED bit set
1748  * hasn't been properly setup for IO.  We kick off an async process
1749  * to fix it up.  The async helper will wait for ordered extents, set
1750  * the delalloc bit and make it safe to write the page.
1751  */
1752 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1753 {
1754         struct inode *inode = page->mapping->host;
1755         struct btrfs_writepage_fixup *fixup;
1756         struct btrfs_root *root = BTRFS_I(inode)->root;
1757
1758         /* this page is properly in the ordered list */
1759         if (TestClearPagePrivate2(page))
1760                 return 0;
1761
1762         if (PageChecked(page))
1763                 return -EAGAIN;
1764
1765         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1766         if (!fixup)
1767                 return -EAGAIN;
1768
1769         SetPageChecked(page);
1770         page_cache_get(page);
1771         fixup->work.func = btrfs_writepage_fixup_worker;
1772         fixup->page = page;
1773         btrfs_queue_worker(&root->fs_info->fixup_workers, &fixup->work);
1774         return -EBUSY;
1775 }
1776
1777 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1778                                        struct inode *inode, u64 file_pos,
1779                                        u64 disk_bytenr, u64 disk_num_bytes,
1780                                        u64 num_bytes, u64 ram_bytes,
1781                                        u8 compression, u8 encryption,
1782                                        u16 other_encoding, int extent_type)
1783 {
1784         struct btrfs_root *root = BTRFS_I(inode)->root;
1785         struct btrfs_file_extent_item *fi;
1786         struct btrfs_path *path;
1787         struct extent_buffer *leaf;
1788         struct btrfs_key ins;
1789         u64 hint;
1790         int ret;
1791
1792         path = btrfs_alloc_path();
1793         if (!path)
1794                 return -ENOMEM;
1795
1796         path->leave_spinning = 1;
1797
1798         /*
1799          * we may be replacing one extent in the tree with another.
1800          * The new extent is pinned in the extent map, and we don't want
1801          * to drop it from the cache until it is completely in the btree.
1802          *
1803          * So, tell btrfs_drop_extents to leave this extent in the cache.
1804          * the caller is expected to unpin it and allow it to be merged
1805          * with the others.
1806          */
1807         ret = btrfs_drop_extents(trans, inode, file_pos, file_pos + num_bytes,
1808                                  &hint, 0);
1809         if (ret)
1810                 goto out;
1811
1812         ins.objectid = btrfs_ino(inode);
1813         ins.offset = file_pos;
1814         ins.type = BTRFS_EXTENT_DATA_KEY;
1815         ret = btrfs_insert_empty_item(trans, root, path, &ins, sizeof(*fi));
1816         if (ret)
1817                 goto out;
1818         leaf = path->nodes[0];
1819         fi = btrfs_item_ptr(leaf, path->slots[0],
1820                             struct btrfs_file_extent_item);
1821         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1822         btrfs_set_file_extent_type(leaf, fi, extent_type);
1823         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
1824         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
1825         btrfs_set_file_extent_offset(leaf, fi, 0);
1826         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1827         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
1828         btrfs_set_file_extent_compression(leaf, fi, compression);
1829         btrfs_set_file_extent_encryption(leaf, fi, encryption);
1830         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
1831
1832         btrfs_unlock_up_safe(path, 1);
1833         btrfs_set_lock_blocking(leaf);
1834
1835         btrfs_mark_buffer_dirty(leaf);
1836
1837         inode_add_bytes(inode, num_bytes);
1838
1839         ins.objectid = disk_bytenr;
1840         ins.offset = disk_num_bytes;
1841         ins.type = BTRFS_EXTENT_ITEM_KEY;
1842         ret = btrfs_alloc_reserved_file_extent(trans, root,
1843                                         root->root_key.objectid,
1844                                         btrfs_ino(inode), file_pos, &ins);
1845 out:
1846         btrfs_free_path(path);
1847
1848         return ret;
1849 }
1850
1851 /*
1852  * helper function for btrfs_finish_ordered_io, this
1853  * just reads in some of the csum leaves to prime them into ram
1854  * before we start the transaction.  It limits the amount of btree
1855  * reads required while inside the transaction.
1856  */
1857 /* as ordered data IO finishes, this gets called so we can finish
1858  * an ordered extent if the range of bytes in the file it covers are
1859  * fully written.
1860  */
1861 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
1862 {
1863         struct inode *inode = ordered_extent->inode;
1864         struct btrfs_root *root = BTRFS_I(inode)->root;
1865         struct btrfs_trans_handle *trans = NULL;
1866         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1867         struct extent_state *cached_state = NULL;
1868         int compress_type = 0;
1869         int ret;
1870         bool nolock;
1871
1872         nolock = btrfs_is_free_space_inode(inode);
1873
1874         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
1875                 ret = -EIO;
1876                 goto out;
1877         }
1878
1879         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
1880                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
1881                 ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
1882                 if (!ret) {
1883                         if (nolock)
1884                                 trans = btrfs_join_transaction_nolock(root);
1885                         else
1886                                 trans = btrfs_join_transaction(root);
1887                         if (IS_ERR(trans))
1888                                 return PTR_ERR(trans);
1889                         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1890                         ret = btrfs_update_inode_fallback(trans, root, inode);
1891                         if (ret) /* -ENOMEM or corruption */
1892                                 btrfs_abort_transaction(trans, root, ret);
1893                 }
1894                 goto out;
1895         }
1896
1897         lock_extent_bits(io_tree, ordered_extent->file_offset,
1898                          ordered_extent->file_offset + ordered_extent->len - 1,
1899                          0, &cached_state);
1900
1901         if (nolock)
1902                 trans = btrfs_join_transaction_nolock(root);
1903         else
1904                 trans = btrfs_join_transaction(root);
1905         if (IS_ERR(trans)) {
1906                 ret = PTR_ERR(trans);
1907                 trans = NULL;
1908                 goto out_unlock;
1909         }
1910         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1911
1912         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
1913                 compress_type = ordered_extent->compress_type;
1914         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
1915                 BUG_ON(compress_type);
1916                 ret = btrfs_mark_extent_written(trans, inode,
1917                                                 ordered_extent->file_offset,
1918                                                 ordered_extent->file_offset +
1919                                                 ordered_extent->len);
1920         } else {
1921                 BUG_ON(root == root->fs_info->tree_root);
1922                 ret = insert_reserved_file_extent(trans, inode,
1923                                                 ordered_extent->file_offset,
1924                                                 ordered_extent->start,
1925                                                 ordered_extent->disk_len,
1926                                                 ordered_extent->len,
1927                                                 ordered_extent->len,
1928                                                 compress_type, 0, 0,
1929                                                 BTRFS_FILE_EXTENT_REG);
1930                 unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
1931                                    ordered_extent->file_offset,
1932                                    ordered_extent->len);
1933         }
1934
1935         if (ret < 0) {
1936                 btrfs_abort_transaction(trans, root, ret);
1937                 goto out_unlock;
1938         }
1939
1940         add_pending_csums(trans, inode, ordered_extent->file_offset,
1941                           &ordered_extent->list);
1942
1943         ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
1944         if (!ret || !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
1945                 ret = btrfs_update_inode_fallback(trans, root, inode);
1946                 if (ret) { /* -ENOMEM or corruption */
1947                         btrfs_abort_transaction(trans, root, ret);
1948                         goto out_unlock;
1949                 }
1950         }
1951         ret = 0;
1952 out_unlock:
1953         unlock_extent_cached(io_tree, ordered_extent->file_offset,
1954                              ordered_extent->file_offset +
1955                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
1956 out:
1957         if (root != root->fs_info->tree_root)
1958                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
1959         if (trans) {
1960                 if (nolock)
1961                         btrfs_end_transaction_nolock(trans, root);
1962                 else
1963                         btrfs_end_transaction(trans, root);
1964         }
1965
1966         if (ret)
1967                 clear_extent_uptodate(io_tree, ordered_extent->file_offset,
1968                                       ordered_extent->file_offset +
1969                                       ordered_extent->len - 1, NULL, GFP_NOFS);
1970
1971         /*
1972          * This needs to be dont to make sure anybody waiting knows we are done
1973          * upating everything for this ordered extent.
1974          */
1975         btrfs_remove_ordered_extent(inode, ordered_extent);
1976
1977         /* once for us */
1978         btrfs_put_ordered_extent(ordered_extent);
1979         /* once for the tree */
1980         btrfs_put_ordered_extent(ordered_extent);
1981
1982         return ret;
1983 }
1984
1985 static void finish_ordered_fn(struct btrfs_work *work)
1986 {
1987         struct btrfs_ordered_extent *ordered_extent;
1988         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
1989         btrfs_finish_ordered_io(ordered_extent);
1990 }
1991
1992 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
1993                                 struct extent_state *state, int uptodate)
1994 {
1995         struct inode *inode = page->mapping->host;
1996         struct btrfs_root *root = BTRFS_I(inode)->root;
1997         struct btrfs_ordered_extent *ordered_extent = NULL;
1998         struct btrfs_workers *workers;
1999
2000         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
2001
2002         ClearPagePrivate2(page);
2003         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
2004                                             end - start + 1, uptodate))
2005                 return 0;
2006
2007         ordered_extent->work.func = finish_ordered_fn;
2008         ordered_extent->work.flags = 0;
2009
2010         if (btrfs_is_free_space_inode(inode))
2011                 workers = &root->fs_info->endio_freespace_worker;
2012         else
2013                 workers = &root->fs_info->endio_write_workers;
2014         btrfs_queue_worker(workers, &ordered_extent->work);
2015
2016         return 0;
2017 }
2018
2019 /*
2020  * when reads are done, we need to check csums to verify the data is correct
2021  * if there's a match, we allow the bio to finish.  If not, the code in
2022  * extent_io.c will try to find good copies for us.
2023  */
2024 static int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,
2025                                struct extent_state *state, int mirror)
2026 {
2027         size_t offset = start - ((u64)page->index << PAGE_CACHE_SHIFT);
2028         struct inode *inode = page->mapping->host;
2029         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2030         char *kaddr;
2031         u64 private = ~(u32)0;
2032         int ret;
2033         struct btrfs_root *root = BTRFS_I(inode)->root;
2034         u32 csum = ~(u32)0;
2035
2036         if (PageChecked(page)) {
2037                 ClearPageChecked(page);
2038                 goto good;
2039         }
2040
2041         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
2042                 goto good;
2043
2044         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
2045             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
2046                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
2047                                   GFP_NOFS);
2048                 return 0;
2049         }
2050
2051         if (state && state->start == start) {
2052                 private = state->private;
2053                 ret = 0;
2054         } else {
2055                 ret = get_state_private(io_tree, start, &private);
2056         }
2057         kaddr = kmap_atomic(page);
2058         if (ret)
2059                 goto zeroit;
2060
2061         csum = btrfs_csum_data(root, kaddr + offset, csum,  end - start + 1);
2062         btrfs_csum_final(csum, (char *)&csum);
2063         if (csum != private)
2064                 goto zeroit;
2065
2066         kunmap_atomic(kaddr);
2067 good:
2068         return 0;
2069
2070 zeroit:
2071         printk_ratelimited(KERN_INFO "btrfs csum failed ino %llu off %llu csum %u "
2072                        "private %llu\n",
2073                        (unsigned long long)btrfs_ino(page->mapping->host),
2074                        (unsigned long long)start, csum,
2075                        (unsigned long long)private);
2076         memset(kaddr + offset, 1, end - start + 1);
2077         flush_dcache_page(page);
2078         kunmap_atomic(kaddr);
2079         if (private == 0)
2080                 return 0;
2081         return -EIO;
2082 }
2083
2084 struct delayed_iput {
2085         struct list_head list;
2086         struct inode *inode;
2087 };
2088
2089 /* JDM: If this is fs-wide, why can't we add a pointer to
2090  * btrfs_inode instead and avoid the allocation? */
2091 void btrfs_add_delayed_iput(struct inode *inode)
2092 {
2093         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2094         struct delayed_iput *delayed;
2095
2096         if (atomic_add_unless(&inode->i_count, -1, 1))
2097                 return;
2098
2099         delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
2100         delayed->inode = inode;
2101
2102         spin_lock(&fs_info->delayed_iput_lock);
2103         list_add_tail(&delayed->list, &fs_info->delayed_iputs);
2104         spin_unlock(&fs_info->delayed_iput_lock);
2105 }
2106
2107 void btrfs_run_delayed_iputs(struct btrfs_root *root)
2108 {
2109         LIST_HEAD(list);
2110         struct btrfs_fs_info *fs_info = root->fs_info;
2111         struct delayed_iput *delayed;
2112         int empty;
2113
2114         spin_lock(&fs_info->delayed_iput_lock);
2115         empty = list_empty(&fs_info->delayed_iputs);
2116         spin_unlock(&fs_info->delayed_iput_lock);
2117         if (empty)
2118                 return;
2119
2120         down_read(&root->fs_info->cleanup_work_sem);
2121         spin_lock(&fs_info->delayed_iput_lock);
2122         list_splice_init(&fs_info->delayed_iputs, &list);
2123         spin_unlock(&fs_info->delayed_iput_lock);
2124
2125         while (!list_empty(&list)) {
2126                 delayed = list_entry(list.next, struct delayed_iput, list);
2127                 list_del(&delayed->list);
2128                 iput(delayed->inode);
2129                 kfree(delayed);
2130         }
2131         up_read(&root->fs_info->cleanup_work_sem);
2132 }
2133
2134 enum btrfs_orphan_cleanup_state {
2135         ORPHAN_CLEANUP_STARTED  = 1,
2136         ORPHAN_CLEANUP_DONE     = 2,
2137 };
2138
2139 /*
2140  * This is called in transaction commit time. If there are no orphan
2141  * files in the subvolume, it removes orphan item and frees block_rsv
2142  * structure.
2143  */
2144 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
2145                               struct btrfs_root *root)
2146 {
2147         struct btrfs_block_rsv *block_rsv;
2148         int ret;
2149
2150         if (atomic_read(&root->orphan_inodes) ||
2151             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
2152                 return;
2153
2154         spin_lock(&root->orphan_lock);
2155         if (atomic_read(&root->orphan_inodes)) {
2156                 spin_unlock(&root->orphan_lock);
2157                 return;
2158         }
2159
2160         if (root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE) {
2161                 spin_unlock(&root->orphan_lock);
2162                 return;
2163         }
2164
2165         block_rsv = root->orphan_block_rsv;
2166         root->orphan_block_rsv = NULL;
2167         spin_unlock(&root->orphan_lock);
2168
2169         if (root->orphan_item_inserted &&
2170             btrfs_root_refs(&root->root_item) > 0) {
2171                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
2172                                             root->root_key.objectid);
2173                 BUG_ON(ret);
2174                 root->orphan_item_inserted = 0;
2175         }
2176
2177         if (block_rsv) {
2178                 WARN_ON(block_rsv->size > 0);
2179                 btrfs_free_block_rsv(root, block_rsv);
2180         }
2181 }
2182
2183 /*
2184  * This creates an orphan entry for the given inode in case something goes
2185  * wrong in the middle of an unlink/truncate.
2186  *
2187  * NOTE: caller of this function should reserve 5 units of metadata for
2188  *       this function.
2189  */
2190 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
2191 {
2192         struct btrfs_root *root = BTRFS_I(inode)->root;
2193         struct btrfs_block_rsv *block_rsv = NULL;
2194         int reserve = 0;
2195         int insert = 0;
2196         int ret;
2197
2198         if (!root->orphan_block_rsv) {
2199                 block_rsv = btrfs_alloc_block_rsv(root);
2200                 if (!block_rsv)
2201                         return -ENOMEM;
2202         }
2203
2204         spin_lock(&root->orphan_lock);
2205         if (!root->orphan_block_rsv) {
2206                 root->orphan_block_rsv = block_rsv;
2207         } else if (block_rsv) {
2208                 btrfs_free_block_rsv(root, block_rsv);
2209                 block_rsv = NULL;
2210         }
2211
2212         if (!test_and_set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
2213                               &BTRFS_I(inode)->runtime_flags)) {
2214 #if 0
2215                 /*
2216                  * For proper ENOSPC handling, we should do orphan
2217                  * cleanup when mounting. But this introduces backward
2218                  * compatibility issue.
2219                  */
2220                 if (!xchg(&root->orphan_item_inserted, 1))
2221                         insert = 2;
2222                 else
2223                         insert = 1;
2224 #endif
2225                 insert = 1;
2226                 atomic_dec(&root->orphan_inodes);
2227         }
2228
2229         if (!test_and_set_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
2230                               &BTRFS_I(inode)->runtime_flags))
2231                 reserve = 1;
2232         spin_unlock(&root->orphan_lock);
2233
2234         /* grab metadata reservation from transaction handle */
2235         if (reserve) {
2236                 ret = btrfs_orphan_reserve_metadata(trans, inode);
2237                 BUG_ON(ret); /* -ENOSPC in reservation; Logic error? JDM */
2238         }
2239
2240         /* insert an orphan item to track this unlinked/truncated file */
2241         if (insert >= 1) {
2242                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
2243                 if (ret && ret != -EEXIST) {
2244                         clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
2245                                   &BTRFS_I(inode)->runtime_flags);
2246                         btrfs_abort_transaction(trans, root, ret);
2247                         return ret;
2248                 }
2249                 ret = 0;
2250         }
2251
2252         /* insert an orphan item to track subvolume contains orphan files */
2253         if (insert >= 2) {
2254                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
2255                                                root->root_key.objectid);
2256                 if (ret && ret != -EEXIST) {
2257                         btrfs_abort_transaction(trans, root, ret);
2258                         return ret;
2259                 }
2260         }
2261         return 0;
2262 }
2263
2264 /*
2265  * We have done the truncate/delete so we can go ahead and remove the orphan
2266  * item for this particular inode.
2267  */
2268 int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode)
2269 {
2270         struct btrfs_root *root = BTRFS_I(inode)->root;
2271         int delete_item = 0;
2272         int release_rsv = 0;
2273         int ret = 0;
2274
2275         spin_lock(&root->orphan_lock);
2276         if (test_and_clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
2277                                &BTRFS_I(inode)->runtime_flags))
2278                 delete_item = 1;
2279
2280         if (test_and_clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
2281                                &BTRFS_I(inode)->runtime_flags))
2282                 release_rsv = 1;
2283         spin_unlock(&root->orphan_lock);
2284
2285         if (trans && delete_item) {
2286                 ret = btrfs_del_orphan_item(trans, root, btrfs_ino(inode));
2287                 BUG_ON(ret); /* -ENOMEM or corruption (JDM: Recheck) */
2288         }
2289
2290         if (release_rsv) {
2291                 btrfs_orphan_release_metadata(inode);
2292                 atomic_dec(&root->orphan_inodes);
2293         }
2294
2295         return 0;
2296 }
2297
2298 /*
2299  * this cleans up any orphans that may be left on the list from the last use
2300  * of this root.
2301  */
2302 int btrfs_orphan_cleanup(struct btrfs_root *root)
2303 {
2304         struct btrfs_path *path;
2305         struct extent_buffer *leaf;
2306         struct btrfs_key key, found_key;
2307         struct btrfs_trans_handle *trans;
2308         struct inode *inode;
2309         u64 last_objectid = 0;
2310         int ret = 0, nr_unlink = 0, nr_truncate = 0;
2311
2312         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
2313                 return 0;
2314
2315         path = btrfs_alloc_path();
2316         if (!path) {
2317                 ret = -ENOMEM;
2318                 goto out;
2319         }
2320         path->reada = -1;
2321
2322         key.objectid = BTRFS_ORPHAN_OBJECTID;
2323         btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
2324         key.offset = (u64)-1;
2325
2326         while (1) {
2327                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2328                 if (ret < 0)
2329                         goto out;
2330
2331                 /*
2332                  * if ret == 0 means we found what we were searching for, which
2333                  * is weird, but possible, so only screw with path if we didn't
2334                  * find the key and see if we have stuff that matches
2335                  */
2336                 if (ret > 0) {
2337                         ret = 0;
2338                         if (path->slots[0] == 0)
2339                                 break;
2340                         path->slots[0]--;
2341                 }
2342
2343                 /* pull out the item */
2344                 leaf = path->nodes[0];
2345                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2346
2347                 /* make sure the item matches what we want */
2348                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
2349                         break;
2350                 if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
2351                         break;
2352
2353                 /* release the path since we're done with it */
2354                 btrfs_release_path(path);
2355
2356                 /*
2357                  * this is where we are basically btrfs_lookup, without the
2358                  * crossing root thing.  we store the inode number in the
2359                  * offset of the orphan item.
2360                  */
2361
2362                 if (found_key.offset == last_objectid) {
2363                         printk(KERN_ERR "btrfs: Error removing orphan entry, "
2364                                "stopping orphan cleanup\n");
2365                         ret = -EINVAL;
2366                         goto out;
2367                 }
2368
2369                 last_objectid = found_key.offset;
2370
2371                 found_key.objectid = found_key.offset;
2372                 found_key.type = BTRFS_INODE_ITEM_KEY;
2373                 found_key.offset = 0;
2374                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
2375                 ret = PTR_RET(inode);
2376                 if (ret && ret != -ESTALE)
2377                         goto out;
2378
2379                 if (ret == -ESTALE && root == root->fs_info->tree_root) {
2380                         struct btrfs_root *dead_root;
2381                         struct btrfs_fs_info *fs_info = root->fs_info;
2382                         int is_dead_root = 0;
2383
2384                         /*
2385                          * this is an orphan in the tree root. Currently these
2386                          * could come from 2 sources:
2387                          *  a) a snapshot deletion in progress
2388                          *  b) a free space cache inode
2389                          * We need to distinguish those two, as the snapshot
2390                          * orphan must not get deleted.
2391                          * find_dead_roots already ran before us, so if this
2392                          * is a snapshot deletion, we should find the root
2393                          * in the dead_roots list
2394                          */
2395                         spin_lock(&fs_info->trans_lock);
2396                         list_for_each_entry(dead_root, &fs_info->dead_roots,
2397                                             root_list) {
2398                                 if (dead_root->root_key.objectid ==
2399                                     found_key.objectid) {
2400                                         is_dead_root = 1;
2401                                         break;
2402                                 }
2403                         }
2404                         spin_unlock(&fs_info->trans_lock);
2405                         if (is_dead_root) {
2406                                 /* prevent this orphan from being found again */
2407                                 key.offset = found_key.objectid - 1;
2408                                 continue;
2409                         }
2410                 }
2411                 /*
2412                  * Inode is already gone but the orphan item is still there,
2413                  * kill the orphan item.
2414                  */
2415                 if (ret == -ESTALE) {
2416                         trans = btrfs_start_transaction(root, 1);
2417                         if (IS_ERR(trans)) {
2418                                 ret = PTR_ERR(trans);
2419                                 goto out;
2420                         }
2421                         printk(KERN_ERR "auto deleting %Lu\n",
2422                                found_key.objectid);
2423                         ret = btrfs_del_orphan_item(trans, root,
2424                                                     found_key.objectid);
2425                         BUG_ON(ret); /* -ENOMEM or corruption (JDM: Recheck) */
2426                         btrfs_end_transaction(trans, root);
2427                         continue;
2428                 }
2429
2430                 /*
2431                  * add this inode to the orphan list so btrfs_orphan_del does
2432                  * the proper thing when we hit it
2433                  */
2434                 set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
2435                         &BTRFS_I(inode)->runtime_flags);
2436
2437                 /* if we have links, this was a truncate, lets do that */
2438                 if (inode->i_nlink) {
2439                         if (!S_ISREG(inode->i_mode)) {
2440                                 WARN_ON(1);
2441                                 iput(inode);
2442                                 continue;
2443                         }
2444                         nr_truncate++;
2445                         ret = btrfs_truncate(inode);
2446                 } else {
2447                         nr_unlink++;
2448                 }
2449
2450                 /* this will do delete_inode and everything for us */
2451                 iput(inode);
2452                 if (ret)
2453                         goto out;
2454         }
2455         /* release the path since we're done with it */
2456         btrfs_release_path(path);
2457
2458         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
2459
2460         if (root->orphan_block_rsv)
2461                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
2462                                         (u64)-1);
2463
2464         if (root->orphan_block_rsv || root->orphan_item_inserted) {
2465                 trans = btrfs_join_transaction(root);
2466                 if (!IS_ERR(trans))
2467                         btrfs_end_transaction(trans, root);
2468         }
2469
2470         if (nr_unlink)
2471                 printk(KERN_INFO "btrfs: unlinked %d orphans\n", nr_unlink);
2472         if (nr_truncate)
2473                 printk(KERN_INFO "btrfs: truncated %d orphans\n", nr_truncate);
2474
2475 out:
2476         if (ret)
2477                 printk(KERN_CRIT "btrfs: could not do orphan cleanup %d\n", ret);
2478         btrfs_free_path(path);
2479         return ret;
2480 }
2481
2482 /*
2483  * very simple check to peek ahead in the leaf looking for xattrs.  If we
2484  * don't find any xattrs, we know there can't be any acls.
2485  *
2486  * slot is the slot the inode is in, objectid is the objectid of the inode
2487  */
2488 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
2489                                           int slot, u64 objectid)
2490 {
2491         u32 nritems = btrfs_header_nritems(leaf);
2492         struct btrfs_key found_key;
2493         int scanned = 0;
2494
2495         slot++;
2496         while (slot < nritems) {
2497                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2498
2499                 /* we found a different objectid, there must not be acls */
2500                 if (found_key.objectid != objectid)
2501                         return 0;
2502
2503                 /* we found an xattr, assume we've got an acl */
2504                 if (found_key.type == BTRFS_XATTR_ITEM_KEY)
2505                         return 1;
2506
2507                 /*
2508                  * we found a key greater than an xattr key, there can't
2509                  * be any acls later on
2510                  */
2511                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
2512                         return 0;
2513
2514                 slot++;
2515                 scanned++;
2516
2517                 /*
2518                  * it goes inode, inode backrefs, xattrs, extents,
2519                  * so if there are a ton of hard links to an inode there can
2520                  * be a lot of backrefs.  Don't waste time searching too hard,
2521                  * this is just an optimization
2522                  */
2523                 if (scanned >= 8)
2524                         break;
2525         }
2526         /* we hit the end of the leaf before we found an xattr or
2527          * something larger than an xattr.  We have to assume the inode
2528          * has acls
2529          */
2530         return 1;
2531 }
2532
2533 /*
2534  * read an inode from the btree into the in-memory inode
2535  */
2536 static void btrfs_read_locked_inode(struct inode *inode)
2537 {
2538         struct btrfs_path *path;
2539         struct extent_buffer *leaf;
2540         struct btrfs_inode_item *inode_item;
2541         struct btrfs_timespec *tspec;
2542         struct btrfs_root *root = BTRFS_I(inode)->root;
2543         struct btrfs_key location;
2544         int maybe_acls;
2545         u32 rdev;
2546         int ret;
2547         bool filled = false;
2548
2549         ret = btrfs_fill_inode(inode, &rdev);
2550         if (!ret)
2551                 filled = true;
2552
2553         path = btrfs_alloc_path();
2554         if (!path)
2555                 goto make_bad;
2556
2557         path->leave_spinning = 1;
2558         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
2559
2560         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
2561         if (ret)
2562                 goto make_bad;
2563
2564         leaf = path->nodes[0];
2565
2566         if (filled)
2567                 goto cache_acl;
2568
2569         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2570                                     struct btrfs_inode_item);
2571         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
2572         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
2573         inode->i_uid = btrfs_inode_uid(leaf, inode_item);
2574         inode->i_gid = btrfs_inode_gid(leaf, inode_item);
2575         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
2576
2577         tspec = btrfs_inode_atime(inode_item);
2578         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2579         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2580
2581         tspec = btrfs_inode_mtime(inode_item);
2582         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2583         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2584
2585         tspec = btrfs_inode_ctime(inode_item);
2586         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2587         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2588
2589         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
2590         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
2591         inode->i_version = btrfs_inode_sequence(leaf, inode_item);
2592         inode->i_generation = BTRFS_I(inode)->generation;
2593         inode->i_rdev = 0;
2594         rdev = btrfs_inode_rdev(leaf, inode_item);
2595
2596         BTRFS_I(inode)->index_cnt = (u64)-1;
2597         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
2598 cache_acl:
2599         /*
2600          * try to precache a NULL acl entry for files that don't have
2601          * any xattrs or acls
2602          */
2603         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
2604                                            btrfs_ino(inode));
2605         if (!maybe_acls)
2606                 cache_no_acl(inode);
2607
2608         btrfs_free_path(path);
2609
2610         switch (inode->i_mode & S_IFMT) {
2611         case S_IFREG:
2612                 inode->i_mapping->a_ops = &btrfs_aops;
2613                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2614                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
2615                 inode->i_fop = &btrfs_file_operations;
2616                 inode->i_op = &btrfs_file_inode_operations;
2617                 break;
2618         case S_IFDIR:
2619                 inode->i_fop = &btrfs_dir_file_operations;
2620                 if (root == root->fs_info->tree_root)
2621                         inode->i_op = &btrfs_dir_ro_inode_operations;
2622                 else
2623                         inode->i_op = &btrfs_dir_inode_operations;
2624                 break;
2625         case S_IFLNK:
2626                 inode->i_op = &btrfs_symlink_inode_operations;
2627                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
2628                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2629                 break;
2630         default:
2631                 inode->i_op = &btrfs_special_inode_operations;
2632                 init_special_inode(inode, inode->i_mode, rdev);
2633                 break;
2634         }
2635
2636         btrfs_update_iflags(inode);
2637         return;
2638
2639 make_bad:
2640         btrfs_free_path(path);
2641         make_bad_inode(inode);
2642 }
2643
2644 /*
2645  * given a leaf and an inode, copy the inode fields into the leaf
2646  */
2647 static void fill_inode_item(struct btrfs_trans_handle *trans,
2648                             struct extent_buffer *leaf,
2649                             struct btrfs_inode_item *item,
2650                             struct inode *inode)
2651 {
2652         btrfs_set_inode_uid(leaf, item, inode->i_uid);
2653         btrfs_set_inode_gid(leaf, item, inode->i_gid);
2654         btrfs_set_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size);
2655         btrfs_set_inode_mode(leaf, item, inode->i_mode);
2656         btrfs_set_inode_nlink(leaf, item, inode->i_nlink);
2657
2658         btrfs_set_timespec_sec(leaf, btrfs_inode_atime(item),
2659                                inode->i_atime.tv_sec);
2660         btrfs_set_timespec_nsec(leaf, btrfs_inode_atime(item),
2661                                 inode->i_atime.tv_nsec);
2662
2663         btrfs_set_timespec_sec(leaf, btrfs_inode_mtime(item),
2664                                inode->i_mtime.tv_sec);
2665         btrfs_set_timespec_nsec(leaf, btrfs_inode_mtime(item),
2666                                 inode->i_mtime.tv_nsec);
2667
2668         btrfs_set_timespec_sec(leaf, btrfs_inode_ctime(item),
2669                                inode->i_ctime.tv_sec);
2670         btrfs_set_timespec_nsec(leaf, btrfs_inode_ctime(item),
2671                                 inode->i_ctime.tv_nsec);
2672
2673         btrfs_set_inode_nbytes(leaf, item, inode_get_bytes(inode));
2674         btrfs_set_inode_generation(leaf, item, BTRFS_I(inode)->generation);
2675         btrfs_set_inode_sequence(leaf, item, inode->i_version);
2676         btrfs_set_inode_transid(leaf, item, trans->transid);
2677         btrfs_set_inode_rdev(leaf, item, inode->i_rdev);
2678         btrfs_set_inode_flags(leaf, item, BTRFS_I(inode)->flags);
2679         btrfs_set_inode_block_group(leaf, item, 0);
2680 }
2681
2682 /*
2683  * copy everything in the in-memory inode into the btree.
2684  */
2685 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
2686                                 struct btrfs_root *root, struct inode *inode)
2687 {
2688         struct btrfs_inode_item *inode_item;
2689         struct btrfs_path *path;
2690         struct extent_buffer *leaf;
2691         int ret;
2692
2693         path = btrfs_alloc_path();
2694         if (!path)
2695                 return -ENOMEM;
2696
2697         path->leave_spinning = 1;
2698         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
2699                                  1);
2700         if (ret) {
2701                 if (ret > 0)
2702                         ret = -ENOENT;
2703                 goto failed;
2704         }
2705
2706         btrfs_unlock_up_safe(path, 1);
2707         leaf = path->nodes[0];
2708         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2709                                     struct btrfs_inode_item);
2710
2711         fill_inode_item(trans, leaf, inode_item, inode);
2712         btrfs_mark_buffer_dirty(leaf);
2713         btrfs_set_inode_last_trans(trans, inode);
2714         ret = 0;
2715 failed:
2716         btrfs_free_path(path);
2717         return ret;
2718 }
2719
2720 /*
2721  * copy everything in the in-memory inode into the btree.
2722  */
2723 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
2724                                 struct btrfs_root *root, struct inode *inode)
2725 {
2726         int ret;
2727
2728         /*
2729          * If the inode is a free space inode, we can deadlock during commit
2730          * if we put it into the delayed code.
2731          *
2732          * The data relocation inode should also be directly updated
2733          * without delay
2734          */
2735         if (!btrfs_is_free_space_inode(inode)
2736             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID) {
2737                 ret = btrfs_delayed_update_inode(trans, root, inode);
2738                 if (!ret)
2739                         btrfs_set_inode_last_trans(trans, inode);
2740                 return ret;
2741         }
2742
2743         return btrfs_update_inode_item(trans, root, inode);
2744 }
2745
2746 static noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
2747                                 struct btrfs_root *root, struct inode *inode)
2748 {
2749         int ret;
2750
2751         ret = btrfs_update_inode(trans, root, inode);
2752         if (ret == -ENOSPC)
2753                 return btrfs_update_inode_item(trans, root, inode);
2754         return ret;
2755 }
2756
2757 /*
2758  * unlink helper that gets used here in inode.c and in the tree logging
2759  * recovery code.  It remove a link in a directory with a given name, and
2760  * also drops the back refs in the inode to the directory
2761  */
2762 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2763                                 struct btrfs_root *root,
2764                                 struct inode *dir, struct inode *inode,
2765                                 const char *name, int name_len)
2766 {
2767         struct btrfs_path *path;
2768         int ret = 0;
2769         struct extent_buffer *leaf;
2770         struct btrfs_dir_item *di;
2771         struct btrfs_key key;
2772         u64 index;
2773         u64 ino = btrfs_ino(inode);
2774         u64 dir_ino = btrfs_ino(dir);
2775
2776         path = btrfs_alloc_path();
2777         if (!path) {
2778                 ret = -ENOMEM;
2779                 goto out;
2780         }
2781
2782         path->leave_spinning = 1;
2783         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
2784                                     name, name_len, -1);
2785         if (IS_ERR(di)) {
2786                 ret = PTR_ERR(di);
2787                 goto err;
2788         }
2789         if (!di) {
2790                 ret = -ENOENT;
2791                 goto err;
2792         }
2793         leaf = path->nodes[0];
2794         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2795         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2796         if (ret)
2797                 goto err;
2798         btrfs_release_path(path);
2799
2800         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
2801                                   dir_ino, &index);
2802         if (ret) {
2803                 printk(KERN_INFO "btrfs failed to delete reference to %.*s, "
2804                        "inode %llu parent %llu\n", name_len, name,
2805                        (unsigned long long)ino, (unsigned long long)dir_ino);
2806                 btrfs_abort_transaction(trans, root, ret);
2807                 goto err;
2808         }
2809
2810         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
2811         if (ret) {
2812                 btrfs_abort_transaction(trans, root, ret);
2813                 goto err;
2814         }
2815
2816         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
2817                                          inode, dir_ino);
2818         if (ret != 0 && ret != -ENOENT) {
2819                 btrfs_abort_transaction(trans, root, ret);
2820                 goto err;
2821         }
2822
2823         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
2824                                            dir, index);
2825         if (ret == -ENOENT)
2826                 ret = 0;
2827 err:
2828         btrfs_free_path(path);
2829         if (ret)
2830                 goto out;
2831
2832         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
2833         inode_inc_iversion(inode);
2834         inode_inc_iversion(dir);
2835         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
2836         ret = btrfs_update_inode(trans, root, dir);
2837 out:
2838         return ret;
2839 }
2840
2841 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2842                        struct btrfs_root *root,
2843                        struct inode *dir, struct inode *inode,
2844                        const char *name, int name_len)
2845 {
2846         int ret;
2847         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
2848         if (!ret) {
2849                 btrfs_drop_nlink(inode);
2850                 ret = btrfs_update_inode(trans, root, inode);
2851         }
2852         return ret;
2853 }
2854                 
2855
2856 /* helper to check if there is any shared block in the path */
2857 static int check_path_shared(struct btrfs_root *root,
2858                              struct btrfs_path *path)
2859 {
2860         struct extent_buffer *eb;
2861         int level;
2862         u64 refs = 1;
2863
2864         for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2865                 int ret;
2866
2867                 if (!path->nodes[level])
2868                         break;
2869                 eb = path->nodes[level];
2870                 if (!btrfs_block_can_be_shared(root, eb))
2871                         continue;
2872                 ret = btrfs_lookup_extent_info(NULL, root, eb->start, eb->len,
2873                                                &refs, NULL);
2874                 if (refs > 1)
2875                         return 1;
2876         }
2877         return 0;
2878 }
2879
2880 /*
2881  * helper to start transaction for unlink and rmdir.
2882  *
2883  * unlink and rmdir are special in btrfs, they do not always free space.
2884  * so in enospc case, we should make sure they will free space before
2885  * allowing them to use the global metadata reservation.
2886  */
2887 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir,
2888                                                        struct dentry *dentry)
2889 {
2890         struct btrfs_trans_handle *trans;
2891         struct btrfs_root *root = BTRFS_I(dir)->root;
2892         struct btrfs_path *path;
2893         struct btrfs_inode_ref *ref;
2894         struct btrfs_dir_item *di;
2895         struct inode *inode = dentry->d_inode;
2896         u64 index;
2897         int check_link = 1;
2898         int err = -ENOSPC;
2899         int ret;
2900         u64 ino = btrfs_ino(inode);
2901         u64 dir_ino = btrfs_ino(dir);
2902
2903         /*
2904          * 1 for the possible orphan item
2905          * 1 for the dir item
2906          * 1 for the dir index
2907          * 1 for the inode ref
2908          * 1 for the inode ref in the tree log
2909          * 2 for the dir entries in the log
2910          * 1 for the inode
2911          */
2912         trans = btrfs_start_transaction(root, 8);
2913         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
2914                 return trans;
2915
2916         if (ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
2917                 return ERR_PTR(-ENOSPC);
2918
2919         /* check if there is someone else holds reference */
2920         if (S_ISDIR(inode->i_mode) && atomic_read(&inode->i_count) > 1)
2921                 return ERR_PTR(-ENOSPC);
2922
2923         if (atomic_read(&inode->i_count) > 2)
2924                 return ERR_PTR(-ENOSPC);
2925
2926         if (xchg(&root->fs_info->enospc_unlink, 1))
2927                 return ERR_PTR(-ENOSPC);
2928
2929         path = btrfs_alloc_path();
2930         if (!path) {
2931                 root->fs_info->enospc_unlink = 0;
2932                 return ERR_PTR(-ENOMEM);
2933         }
2934
2935         /* 1 for the orphan item */
2936         trans = btrfs_start_transaction(root, 1);
2937         if (IS_ERR(trans)) {
2938                 btrfs_free_path(path);
2939                 root->fs_info->enospc_unlink = 0;
2940                 return trans;
2941         }
2942
2943         path->skip_locking = 1;
2944         path->search_commit_root = 1;
2945
2946         ret = btrfs_lookup_inode(trans, root, path,
2947                                 &BTRFS_I(dir)->location, 0);
2948         if (ret < 0) {
2949                 err = ret;
2950                 goto out;
2951         }
2952         if (ret == 0) {
2953                 if (check_path_shared(root, path))
2954                         goto out;
2955         } else {
2956                 check_link = 0;
2957         }
2958         btrfs_release_path(path);
2959
2960         ret = btrfs_lookup_inode(trans, root, path,
2961                                 &BTRFS_I(inode)->location, 0);
2962         if (ret < 0) {
2963                 err = ret;
2964                 goto out;
2965         }
2966         if (ret == 0) {
2967                 if (check_path_shared(root, path))
2968                         goto out;
2969         } else {
2970                 check_link = 0;
2971         }
2972         btrfs_release_path(path);
2973
2974         if (ret == 0 && S_ISREG(inode->i_mode)) {
2975                 ret = btrfs_lookup_file_extent(trans, root, path,
2976                                                ino, (u64)-1, 0);
2977                 if (ret < 0) {
2978                         err = ret;
2979                         goto out;
2980                 }
2981                 BUG_ON(ret == 0); /* Corruption */
2982                 if (check_path_shared(root, path))
2983                         goto out;
2984                 btrfs_release_path(path);
2985         }
2986
2987         if (!check_link) {
2988                 err = 0;
2989                 goto out;
2990         }
2991
2992         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
2993                                 dentry->d_name.name, dentry->d_name.len, 0);
2994         if (IS_ERR(di)) {
2995                 err = PTR_ERR(di);
2996                 goto out;
2997         }
2998         if (di) {
2999                 if (check_path_shared(root, path))
3000                         goto out;
3001         } else {
3002                 err = 0;
3003                 goto out;
3004         }
3005         btrfs_release_path(path);
3006
3007         ref = btrfs_lookup_inode_ref(trans, root, path,
3008                                 dentry->d_name.name, dentry->d_name.len,
3009                                 ino, dir_ino, 0);
3010         if (IS_ERR(ref)) {
3011                 err = PTR_ERR(ref);
3012                 goto out;
3013         }
3014         BUG_ON(!ref); /* Logic error */
3015         if (check_path_shared(root, path))
3016                 goto out;
3017         index = btrfs_inode_ref_index(path->nodes[0], ref);
3018         btrfs_release_path(path);
3019
3020         /*
3021          * This is a commit root search, if we can lookup inode item and other
3022          * relative items in the commit root, it means the transaction of
3023          * dir/file creation has been committed, and the dir index item that we
3024          * delay to insert has also been inserted into the commit root. So
3025          * we needn't worry about the delayed insertion of the dir index item
3026          * here.
3027          */
3028         di = btrfs_lookup_dir_index_item(trans, root, path, dir_ino, index,
3029                                 dentry->d_name.name, dentry->d_name.len, 0);
3030         if (IS_ERR(di)) {
3031                 err = PTR_ERR(di);
3032                 goto out;
3033         }
3034         BUG_ON(ret == -ENOENT);
3035         if (check_path_shared(root, path))
3036                 goto out;
3037
3038         err = 0;
3039 out:
3040         btrfs_free_path(path);
3041         /* Migrate the orphan reservation over */
3042         if (!err)
3043                 err = btrfs_block_rsv_migrate(trans->block_rsv,
3044                                 &root->fs_info->global_block_rsv,
3045                                 trans->bytes_reserved);
3046
3047         if (err) {
3048                 btrfs_end_transaction(trans, root);
3049                 root->fs_info->enospc_unlink = 0;
3050                 return ERR_PTR(err);
3051         }
3052
3053         trans->block_rsv = &root->fs_info->global_block_rsv;
3054         return trans;
3055 }
3056
3057 static void __unlink_end_trans(struct btrfs_trans_handle *trans,
3058                                struct btrfs_root *root)
3059 {
3060         if (trans->block_rsv == &root->fs_info->global_block_rsv) {
3061                 btrfs_block_rsv_release(root, trans->block_rsv,
3062                                         trans->bytes_reserved);
3063                 trans->block_rsv = &root->fs_info->trans_block_rsv;
3064                 BUG_ON(!root->fs_info->enospc_unlink);
3065                 root->fs_info->enospc_unlink = 0;
3066         }
3067         btrfs_end_transaction(trans, root);
3068 }
3069
3070 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
3071 {
3072         struct btrfs_root *root = BTRFS_I(dir)->root;
3073         struct btrfs_trans_handle *trans;
3074         struct inode *inode = dentry->d_inode;
3075         int ret;
3076         unsigned long nr = 0;
3077
3078         trans = __unlink_start_trans(dir, dentry);
3079         if (IS_ERR(trans))
3080                 return PTR_ERR(trans);
3081
3082         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
3083
3084         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3085                                  dentry->d_name.name, dentry->d_name.len);
3086         if (ret)
3087                 goto out;
3088
3089         if (inode->i_nlink == 0) {
3090                 ret = btrfs_orphan_add(trans, inode);
3091                 if (ret)
3092                         goto out;
3093         }
3094
3095 out:
3096         nr = trans->blocks_used;
3097         __unlink_end_trans(trans, root);
3098         btrfs_btree_balance_dirty(root, nr);
3099         return ret;
3100 }
3101
3102 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
3103                         struct btrfs_root *root,
3104                         struct inode *dir, u64 objectid,
3105                         const char *name, int name_len)
3106 {
3107         struct btrfs_path *path;
3108         struct extent_buffer *leaf;
3109         struct btrfs_dir_item *di;
3110         struct btrfs_key key;
3111         u64 index;
3112         int ret;
3113         u64 dir_ino = btrfs_ino(dir);
3114
3115         path = btrfs_alloc_path();
3116         if (!path)
3117                 return -ENOMEM;
3118
3119         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3120                                    name, name_len, -1);
3121         if (IS_ERR_OR_NULL(di)) {
3122                 if (!di)
3123                         ret = -ENOENT;
3124                 else
3125                         ret = PTR_ERR(di);
3126                 goto out;
3127         }
3128
3129         leaf = path->nodes[0];
3130         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3131         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3132         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3133         if (ret) {
3134                 btrfs_abort_transaction(trans, root, ret);
3135                 goto out;
3136         }
3137         btrfs_release_path(path);
3138
3139         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
3140                                  objectid, root->root_key.objectid,
3141                                  dir_ino, &index, name, name_len);
3142         if (ret < 0) {
3143                 if (ret != -ENOENT) {
3144                         btrfs_abort_transaction(trans, root, ret);
3145                         goto out;
3146                 }
3147                 di = btrfs_search_dir_index_item(root, path, dir_ino,
3148                                                  name, name_len);
3149                 if (IS_ERR_OR_NULL(di)) {
3150                         if (!di)
3151                                 ret = -ENOENT;
3152                         else
3153                                 ret = PTR_ERR(di);
3154                         btrfs_abort_transaction(trans, root, ret);
3155                         goto out;
3156                 }
3157
3158                 leaf = path->nodes[0];
3159                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3160                 btrfs_release_path(path);
3161                 index = key.offset;
3162         }
3163         btrfs_release_path(path);
3164
3165         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3166         if (ret) {
3167                 btrfs_abort_transaction(trans, root, ret);
3168                 goto out;
3169         }
3170
3171         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3172         inode_inc_iversion(dir);
3173         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3174         ret = btrfs_update_inode(trans, root, dir);
3175         if (ret)
3176                 btrfs_abort_transaction(trans, root, ret);
3177 out:
3178         btrfs_free_path(path);
3179         return ret;
3180 }
3181
3182 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
3183 {
3184         struct inode *inode = dentry->d_inode;
3185         int err = 0;
3186         struct btrfs_root *root = BTRFS_I(dir)->root;
3187         struct btrfs_trans_handle *trans;
3188         unsigned long nr = 0;
3189
3190         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE ||
3191             btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
3192                 return -ENOTEMPTY;
3193
3194         trans = __unlink_start_trans(dir, dentry);
3195         if (IS_ERR(trans))
3196                 return PTR_ERR(trans);
3197
3198         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
3199                 err = btrfs_unlink_subvol(trans, root, dir,
3200                                           BTRFS_I(inode)->location.objectid,
3201                                           dentry->d_name.name,
3202                                           dentry->d_name.len);
3203                 goto out;
3204         }
3205
3206         err = btrfs_orphan_add(trans, inode);
3207         if (err)
3208                 goto out;
3209
3210         /* now the directory is empty */
3211         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3212                                  dentry->d_name.name, dentry->d_name.len);
3213         if (!err)
3214                 btrfs_i_size_write(inode, 0);
3215 out:
3216         nr = trans->blocks_used;
3217         __unlink_end_trans(trans, root);
3218         btrfs_btree_balance_dirty(root, nr);
3219
3220         return err;
3221 }
3222
3223 /*
3224  * this can truncate away extent items, csum items and directory items.
3225  * It starts at a high offset and removes keys until it can't find
3226  * any higher than new_size
3227  *
3228  * csum items that cross the new i_size are truncated to the new size
3229  * as well.
3230  *
3231  * min_type is the minimum key type to truncate down to.  If set to 0, this
3232  * will kill all the items on this inode, including the INODE_ITEM_KEY.
3233  */
3234 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
3235                                struct btrfs_root *root,
3236                                struct inode *inode,
3237                                u64 new_size, u32 min_type)
3238 {
3239         struct btrfs_path *path;
3240         struct extent_buffer *leaf;
3241         struct btrfs_file_extent_item *fi;
3242         struct btrfs_key key;
3243         struct btrfs_key found_key;
3244         u64 extent_start = 0;
3245         u64 extent_num_bytes = 0;
3246         u64 extent_offset = 0;
3247         u64 item_end = 0;
3248         u64 mask = root->sectorsize - 1;
3249         u32 found_type = (u8)-1;
3250         int found_extent;
3251         int del_item;
3252         int pending_del_nr = 0;
3253         int pending_del_slot = 0;
3254         int extent_type = -1;
3255         int ret;
3256         int err = 0;
3257         u64 ino = btrfs_ino(inode);
3258
3259         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
3260
3261         path = btrfs_alloc_path();
3262         if (!path)
3263                 return -ENOMEM;
3264         path->reada = -1;
3265
3266         if (root->ref_cows || root == root->fs_info->tree_root)
3267                 btrfs_drop_extent_cache(inode, new_size & (~mask), (u64)-1, 0);
3268
3269         /*
3270          * This function is also used to drop the items in the log tree before
3271          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
3272          * it is used to drop the loged items. So we shouldn't kill the delayed
3273          * items.
3274          */
3275         if (min_type == 0 && root == BTRFS_I(inode)->root)
3276                 btrfs_kill_delayed_inode_items(inode);
3277
3278         key.objectid = ino;
3279         key.offset = (u64)-1;
3280         key.type = (u8)-1;
3281
3282 search_again:
3283         path->leave_spinning = 1;
3284         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3285         if (ret < 0) {
3286                 err = ret;
3287                 goto out;
3288         }
3289
3290         if (ret > 0) {
3291                 /* there are no items in the tree for us to truncate, we're
3292                  * done
3293                  */
3294                 if (path->slots[0] == 0)
3295                         goto out;
3296                 path->slots[0]--;
3297         }
3298
3299         while (1) {
3300                 fi = NULL;
3301                 leaf = path->nodes[0];
3302                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3303                 found_type = btrfs_key_type(&found_key);
3304
3305                 if (found_key.objectid != ino)
3306                         break;
3307
3308                 if (found_type < min_type)
3309                         break;
3310
3311                 item_end = found_key.offset;
3312                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
3313                         fi = btrfs_item_ptr(leaf, path->slots[0],
3314                                             struct btrfs_file_extent_item);
3315                         extent_type = btrfs_file_extent_type(leaf, fi);
3316                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3317                                 item_end +=
3318                                     btrfs_file_extent_num_bytes(leaf, fi);
3319                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3320                                 item_end += btrfs_file_extent_inline_len(leaf,
3321                                                                          fi);
3322                         }
3323                         item_end--;
3324                 }
3325                 if (found_type > min_type) {
3326                         del_item = 1;
3327                 } else {
3328                         if (item_end < new_size)
3329                                 break;
3330                         if (found_key.offset >= new_size)
3331                                 del_item = 1;
3332                         else
3333                                 del_item = 0;
3334                 }
3335                 found_extent = 0;
3336                 /* FIXME, shrink the extent if the ref count is only 1 */
3337                 if (found_type != BTRFS_EXTENT_DATA_KEY)
3338                         goto delete;
3339
3340                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3341                         u64 num_dec;
3342                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
3343                         if (!del_item) {
3344                                 u64 orig_num_bytes =
3345                                         btrfs_file_extent_num_bytes(leaf, fi);
3346                                 extent_num_bytes = new_size -
3347                                         found_key.offset + root->sectorsize - 1;
3348                                 extent_num_bytes = extent_num_bytes &
3349                                         ~((u64)root->sectorsize - 1);
3350                                 btrfs_set_file_extent_num_bytes(leaf, fi,
3351                                                          extent_num_bytes);
3352                                 num_dec = (orig_num_bytes -
3353                                            extent_num_bytes);
3354                                 if (root->ref_cows && extent_start != 0)
3355                                         inode_sub_bytes(inode, num_dec);
3356                                 btrfs_mark_buffer_dirty(leaf);
3357                         } else {
3358                                 extent_num_bytes =
3359                                         btrfs_file_extent_disk_num_bytes(leaf,
3360                                                                          fi);
3361                                 extent_offset = found_key.offset -
3362                                         btrfs_file_extent_offset(leaf, fi);
3363
3364                                 /* FIXME blocksize != 4096 */
3365                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
3366                                 if (extent_start != 0) {
3367                                         found_extent = 1;
3368                                         if (root->ref_cows)
3369                                                 inode_sub_bytes(inode, num_dec);
3370                                 }
3371                         }
3372                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3373                         /*
3374                          * we can't truncate inline items that have had
3375                          * special encodings
3376                          */
3377                         if (!del_item &&
3378                             btrfs_file_extent_compression(leaf, fi) == 0 &&
3379                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
3380                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
3381                                 u32 size = new_size - found_key.offset;
3382
3383                                 if (root->ref_cows) {
3384                                         inode_sub_bytes(inode, item_end + 1 -
3385                                                         new_size);
3386                                 }
3387                                 size =
3388                                     btrfs_file_extent_calc_inline_size(size);
3389                                 btrfs_truncate_item(trans, root, path,
3390                                                     size, 1);
3391                         } else if (root->ref_cows) {
3392                                 inode_sub_bytes(inode, item_end + 1 -
3393                                                 found_key.offset);
3394                         }
3395                 }
3396 delete:
3397                 if (del_item) {
3398                         if (!pending_del_nr) {
3399                                 /* no pending yet, add ourselves */
3400                                 pending_del_slot = path->slots[0];
3401                                 pending_del_nr = 1;
3402                         } else if (pending_del_nr &&
3403                                    path->slots[0] + 1 == pending_del_slot) {
3404                                 /* hop on the pending chunk */
3405                                 pending_del_nr++;
3406                                 pending_del_slot = path->slots[0];
3407                         } else {
3408                                 BUG();
3409                         }
3410                 } else {
3411                         break;
3412                 }
3413                 if (found_extent && (root->ref_cows ||
3414                                      root == root->fs_info->tree_root)) {
3415                         btrfs_set_path_blocking(path);
3416                         ret = btrfs_free_extent(trans, root, extent_start,
3417                                                 extent_num_bytes, 0,
3418                                                 btrfs_header_owner(leaf),
3419                                                 ino, extent_offset, 0);
3420                         BUG_ON(ret);
3421                 }
3422
3423                 if (found_type == BTRFS_INODE_ITEM_KEY)
3424                         break;
3425
3426                 if (path->slots[0] == 0 ||
3427                     path->slots[0] != pending_del_slot) {
3428                         if (root->ref_cows &&
3429                             BTRFS_I(inode)->location.objectid !=
3430                                                 BTRFS_FREE_INO_OBJECTID) {
3431                                 err = -EAGAIN;
3432                                 goto out;
3433                         }
3434                         if (pending_del_nr) {
3435                                 ret = btrfs_del_items(trans, root, path,
3436                                                 pending_del_slot,
3437                                                 pending_del_nr);
3438                                 if (ret) {
3439                                         btrfs_abort_transaction(trans,
3440                                                                 root, ret);
3441                                         goto error;
3442                                 }
3443                                 pending_del_nr = 0;
3444                         }
3445                         btrfs_release_path(path);
3446                         goto search_again;
3447                 } else {
3448                         path->slots[0]--;
3449                 }
3450         }
3451 out:
3452         if (pending_del_nr) {
3453                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
3454                                       pending_del_nr);
3455                 if (ret)
3456                         btrfs_abort_transaction(trans, root, ret);
3457         }
3458 error:
3459         btrfs_free_path(path);
3460         return err;
3461 }
3462
3463 /*
3464  * taken from block_truncate_page, but does cow as it zeros out
3465  * any bytes left in the last page in the file.
3466  */
3467 static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
3468 {
3469         struct inode *inode = mapping->host;
3470         struct btrfs_root *root = BTRFS_I(inode)->root;
3471         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3472         struct btrfs_ordered_extent *ordered;
3473         struct extent_state *cached_state = NULL;
3474         char *kaddr;
3475         u32 blocksize = root->sectorsize;
3476         pgoff_t index = from >> PAGE_CACHE_SHIFT;
3477         unsigned offset = from & (PAGE_CACHE_SIZE-1);
3478         struct page *page;
3479         gfp_t mask = btrfs_alloc_write_mask(mapping);
3480         int ret = 0;
3481         u64 page_start;
3482         u64 page_end;
3483
3484         if ((offset & (blocksize - 1)) == 0)
3485                 goto out;
3486         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
3487         if (ret)
3488                 goto out;
3489
3490         ret = -ENOMEM;
3491 again:
3492         page = find_or_create_page(mapping, index, mask);
3493         if (!page) {
3494                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
3495                 goto out;
3496         }
3497
3498         page_start = page_offset(page);
3499         page_end = page_start + PAGE_CACHE_SIZE - 1;
3500
3501         if (!PageUptodate(page)) {
3502                 ret = btrfs_readpage(NULL, page);
3503                 lock_page(page);
3504                 if (page->mapping != mapping) {
3505                         unlock_page(page);
3506                         page_cache_release(page);
3507                         goto again;
3508                 }
3509                 if (!PageUptodate(page)) {
3510                         ret = -EIO;
3511                         goto out_unlock;
3512                 }
3513         }
3514         wait_on_page_writeback(page);
3515
3516         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
3517         set_page_extent_mapped(page);
3518
3519         ordered = btrfs_lookup_ordered_extent(inode, page_start);
3520         if (ordered) {
3521                 unlock_extent_cached(io_tree, page_start, page_end,
3522                                      &cached_state, GFP_NOFS);
3523                 unlock_page(page);
3524                 page_cache_release(page);
3525                 btrfs_start_ordered_extent(inode, ordered, 1);
3526                 btrfs_put_ordered_extent(ordered);
3527                 goto again;
3528         }
3529
3530         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
3531                           EXTENT_DIRTY | EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING,
3532                           0, 0, &cached_state, GFP_NOFS);
3533
3534         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
3535                                         &cached_state);
3536         if (ret) {
3537                 unlock_extent_cached(io_tree, page_start, page_end,
3538                                      &cached_state, GFP_NOFS);
3539                 goto out_unlock;
3540         }
3541
3542         ret = 0;
3543         if (offset != PAGE_CACHE_SIZE) {
3544                 kaddr = kmap(page);
3545                 memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
3546                 flush_dcache_page(page);
3547                 kunmap(page);
3548         }
3549         ClearPageChecked(page);
3550         set_page_dirty(page);
3551         unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
3552                              GFP_NOFS);
3553
3554 out_unlock:
3555         if (ret)
3556                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
3557         unlock_page(page);
3558         page_cache_release(page);
3559 out:
3560         return ret;
3561 }
3562
3563 /*
3564  * This function puts in dummy file extents for the area we're creating a hole
3565  * for.  So if we are truncating this file to a larger size we need to insert
3566  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
3567  * the range between oldsize and size
3568  */
3569 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
3570 {
3571         struct btrfs_trans_handle *trans;
3572         struct btrfs_root *root = BTRFS_I(inode)->root;
3573         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3574         struct extent_map *em = NULL;
3575         struct extent_state *cached_state = NULL;
3576         u64 mask = root->sectorsize - 1;
3577         u64 hole_start = (oldsize + mask) & ~mask;
3578         u64 block_end = (size + mask) & ~mask;
3579         u64 last_byte;
3580         u64 cur_offset;
3581         u64 hole_size;
3582         int err = 0;
3583
3584         if (size <= hole_start)
3585                 return 0;
3586
3587         while (1) {
3588                 struct btrfs_ordered_extent *ordered;
3589                 btrfs_wait_ordered_range(inode, hole_start,
3590                                          block_end - hole_start);
3591                 lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
3592                                  &cached_state);
3593                 ordered = btrfs_lookup_ordered_extent(inode, hole_start);
3594                 if (!ordered)
3595                         break;
3596                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
3597                                      &cached_state, GFP_NOFS);
3598                 btrfs_put_ordered_extent(ordered);
3599         }
3600
3601         cur_offset = hole_start;
3602         while (1) {
3603                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
3604                                 block_end - cur_offset, 0);
3605                 if (IS_ERR(em)) {
3606                         err = PTR_ERR(em);
3607                         break;
3608                 }
3609                 last_byte = min(extent_map_end(em), block_end);
3610                 last_byte = (last_byte + mask) & ~mask;
3611                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
3612                         u64 hint_byte = 0;
3613                         hole_size = last_byte - cur_offset;
3614
3615                         trans = btrfs_start_transaction(root, 3);
3616                         if (IS_ERR(trans)) {
3617                                 err = PTR_ERR(trans);
3618                                 break;
3619                         }
3620
3621                         err = btrfs_drop_extents(trans, inode, cur_offset,
3622                                                  cur_offset + hole_size,
3623                                                  &hint_byte, 1);
3624                         if (err) {
3625                                 btrfs_abort_transaction(trans, root, err);
3626                                 btrfs_end_transaction(trans, root);
3627                                 break;
3628                         }
3629
3630                         err = btrfs_insert_file_extent(trans, root,
3631                                         btrfs_ino(inode), cur_offset, 0,
3632                                         0, hole_size, 0, hole_size,
3633                                         0, 0, 0);
3634                         if (err) {
3635                                 btrfs_abort_transaction(trans, root, err);
3636                                 btrfs_end_transaction(trans, root);
3637                                 break;
3638                         }
3639
3640                         btrfs_drop_extent_cache(inode, hole_start,
3641                                         last_byte - 1, 0);
3642
3643                         btrfs_update_inode(trans, root, inode);
3644                         btrfs_end_transaction(trans, root);
3645                 }
3646                 free_extent_map(em);
3647                 em = NULL;
3648                 cur_offset = last_byte;
3649                 if (cur_offset >= block_end)
3650                         break;
3651         }
3652
3653         free_extent_map(em);
3654         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
3655                              GFP_NOFS);
3656         return err;
3657 }
3658
3659 static int btrfs_setsize(struct inode *inode, loff_t newsize)
3660 {
3661         struct btrfs_root *root = BTRFS_I(inode)->root;
3662         struct btrfs_trans_handle *trans;
3663         loff_t oldsize = i_size_read(inode);
3664         int ret;
3665
3666         if (newsize == oldsize)
3667                 return 0;
3668
3669         if (newsize > oldsize) {
3670                 truncate_pagecache(inode, oldsize, newsize);
3671                 ret = btrfs_cont_expand(inode, oldsize, newsize);
3672                 if (ret)
3673                         return ret;
3674
3675                 trans = btrfs_start_transaction(root, 1);
3676                 if (IS_ERR(trans))
3677                         return PTR_ERR(trans);
3678
3679                 i_size_write(inode, newsize);
3680                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
3681                 ret = btrfs_update_inode(trans, root, inode);
3682                 btrfs_end_transaction(trans, root);
3683         } else {
3684
3685                 /*
3686                  * We're truncating a file that used to have good data down to
3687                  * zero. Make sure it gets into the ordered flush list so that
3688                  * any new writes get down to disk quickly.
3689                  */
3690                 if (newsize == 0)
3691                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
3692                                 &BTRFS_I(inode)->runtime_flags);
3693
3694                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
3695                 truncate_setsize(inode, newsize);
3696                 ret = btrfs_truncate(inode);
3697         }
3698
3699         return ret;
3700 }
3701
3702 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
3703 {
3704         struct inode *inode = dentry->d_inode;
3705         struct btrfs_root *root = BTRFS_I(inode)->root;
3706         int err;
3707
3708         if (btrfs_root_readonly(root))
3709                 return -EROFS;
3710
3711         err = inode_change_ok(inode, attr);
3712         if (err)
3713                 return err;
3714
3715         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
3716                 err = btrfs_setsize(inode, attr->ia_size);
3717                 if (err)
3718                         return err;
3719         }
3720
3721         if (attr->ia_valid) {
3722                 setattr_copy(inode, attr);
3723                 inode_inc_iversion(inode);
3724                 err = btrfs_dirty_inode(inode);
3725
3726                 if (!err && attr->ia_valid & ATTR_MODE)
3727                         err = btrfs_acl_chmod(inode);
3728         }
3729
3730         return err;
3731 }
3732
3733 void btrfs_evict_inode(struct inode *inode)
3734 {
3735         struct btrfs_trans_handle *trans;
3736         struct btrfs_root *root = BTRFS_I(inode)->root;
3737         struct btrfs_block_rsv *rsv, *global_rsv;
3738         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
3739         unsigned long nr;
3740         int ret;
3741
3742         trace_btrfs_inode_evict(inode);
3743
3744         truncate_inode_pages(&inode->i_data, 0);
3745         if (inode->i_nlink && (btrfs_root_refs(&root->root_item) != 0 ||
3746                                btrfs_is_free_space_inode(inode)))
3747                 goto no_delete;
3748
3749         if (is_bad_inode(inode)) {
3750                 btrfs_orphan_del(NULL, inode);
3751                 goto no_delete;
3752         }
3753         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
3754         btrfs_wait_ordered_range(inode, 0, (u64)-1);
3755
3756         if (root->fs_info->log_root_recovering) {
3757                 BUG_ON(test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3758                                  &BTRFS_I(inode)->runtime_flags));
3759                 goto no_delete;
3760         }
3761
3762         if (inode->i_nlink > 0) {
3763                 BUG_ON(btrfs_root_refs(&root->root_item) != 0);
3764                 goto no_delete;
3765         }
3766
3767         rsv = btrfs_alloc_block_rsv(root);
3768         if (!rsv) {
3769                 btrfs_orphan_del(NULL, inode);
3770                 goto no_delete;
3771         }
3772         rsv->size = min_size;
3773         global_rsv = &root->fs_info->global_block_rsv;
3774
3775         btrfs_i_size_write(inode, 0);
3776
3777         /*
3778          * This is a bit simpler than btrfs_truncate since
3779          *
3780          * 1) We've already reserved our space for our orphan item in the
3781          *    unlink.
3782          * 2) We're going to delete the inode item, so we don't need to update
3783          *    it at all.
3784          *
3785          * So we just need to reserve some slack space in case we add bytes when
3786          * doing the truncate.
3787          */
3788         while (1) {
3789                 ret = btrfs_block_rsv_refill_noflush(root, rsv, min_size);
3790
3791                 /*
3792                  * Try and steal from the global reserve since we will
3793                  * likely not use this space anyway, we want to try as
3794                  * hard as possible to get this to work.
3795                  */
3796                 if (ret)
3797                         ret = btrfs_block_rsv_migrate(global_rsv, rsv, min_size);
3798
3799                 if (ret) {
3800                         printk(KERN_WARNING "Could not get space for a "
3801                                "delete, will truncate on mount %d\n", ret);
3802                         btrfs_orphan_del(NULL, inode);
3803                         btrfs_free_block_rsv(root, rsv);
3804                         goto no_delete;
3805                 }
3806
3807                 trans = btrfs_start_transaction(root, 0);
3808                 if (IS_ERR(trans)) {
3809                         btrfs_orphan_del(NULL, inode);
3810                         btrfs_free_block_rsv(root, rsv);
3811                         goto no_delete;
3812                 }
3813
3814                 trans->block_rsv = rsv;
3815
3816                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
3817                 if (ret != -EAGAIN)
3818                         break;
3819
3820                 nr = trans->blocks_used;
3821                 btrfs_end_transaction(trans, root);
3822                 trans = NULL;
3823                 btrfs_btree_balance_dirty(root, nr);
3824         }
3825
3826         btrfs_free_block_rsv(root, rsv);
3827
3828         if (ret == 0) {
3829                 trans->block_rsv = root->orphan_block_rsv;
3830                 ret = btrfs_orphan_del(trans, inode);
3831                 BUG_ON(ret);
3832         }
3833
3834         trans->block_rsv = &root->fs_info->trans_block_rsv;
3835         if (!(root == root->fs_info->tree_root ||
3836               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
3837                 btrfs_return_ino(root, btrfs_ino(inode));
3838
3839         nr = trans->blocks_used;
3840         btrfs_end_transaction(trans, root);
3841         btrfs_btree_balance_dirty(root, nr);
3842 no_delete:
3843         clear_inode(inode);
3844         return;
3845 }
3846
3847 /*
3848  * this returns the key found in the dir entry in the location pointer.
3849  * If no dir entries were found, location->objectid is 0.
3850  */
3851 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
3852                                struct btrfs_key *location)
3853 {
3854         const char *name = dentry->d_name.name;
3855         int namelen = dentry->d_name.len;
3856         struct btrfs_dir_item *di;
3857         struct btrfs_path *path;
3858         struct btrfs_root *root = BTRFS_I(dir)->root;
3859         int ret = 0;
3860
3861         path = btrfs_alloc_path();
3862         if (!path)
3863                 return -ENOMEM;
3864
3865         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
3866                                     namelen, 0);
3867         if (IS_ERR(di))
3868                 ret = PTR_ERR(di);
3869
3870         if (IS_ERR_OR_NULL(di))
3871                 goto out_err;
3872
3873         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
3874 out:
3875         btrfs_free_path(path);
3876         return ret;
3877 out_err:
3878         location->objectid = 0;
3879         goto out;
3880 }
3881
3882 /*
3883  * when we hit a tree root in a directory, the btrfs part of the inode
3884  * needs to be changed to reflect the root directory of the tree root.  This
3885  * is kind of like crossing a mount point.
3886  */
3887 static int fixup_tree_root_location(struct btrfs_root *root,
3888                                     struct inode *dir,
3889                                     struct dentry *dentry,
3890                                     struct btrfs_key *location,
3891                                     struct btrfs_root **sub_root)
3892 {
3893         struct btrfs_path *path;
3894         struct btrfs_root *new_root;
3895         struct btrfs_root_ref *ref;
3896         struct extent_buffer *leaf;
3897         int ret;
3898         int err = 0;
3899
3900         path = btrfs_alloc_path();
3901         if (!path) {
3902                 err = -ENOMEM;
3903                 goto out;
3904         }
3905
3906         err = -ENOENT;
3907         ret = btrfs_find_root_ref(root->fs_info->tree_root, path,
3908                                   BTRFS_I(dir)->root->root_key.objectid,
3909                                   location->objectid);
3910         if (ret) {
3911                 if (ret < 0)
3912                         err = ret;
3913                 goto out;
3914         }
3915
3916         leaf = path->nodes[0];
3917         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
3918         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
3919             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
3920                 goto out;
3921
3922         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
3923                                    (unsigned long)(ref + 1),
3924                                    dentry->d_name.len);
3925         if (ret)
3926                 goto out;
3927
3928         btrfs_release_path(path);
3929
3930         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
3931         if (IS_ERR(new_root)) {
3932                 err = PTR_ERR(new_root);
3933                 goto out;
3934         }
3935
3936         if (btrfs_root_refs(&new_root->root_item) == 0) {
3937                 err = -ENOENT;
3938                 goto out;
3939         }
3940
3941         *sub_root = new_root;
3942         location->objectid = btrfs_root_dirid(&new_root->root_item);
3943         location->type = BTRFS_INODE_ITEM_KEY;
3944         location->offset = 0;
3945         err = 0;
3946 out:
3947         btrfs_free_path(path);
3948         return err;
3949 }
3950
3951 static void inode_tree_add(struct inode *inode)
3952 {
3953         struct btrfs_root *root = BTRFS_I(inode)->root;
3954         struct btrfs_inode *entry;
3955         struct rb_node **p;
3956         struct rb_node *parent;
3957         u64 ino = btrfs_ino(inode);
3958 again:
3959         p = &root->inode_tree.rb_node;
3960         parent = NULL;
3961
3962         if (inode_unhashed(inode))
3963                 return;
3964
3965         spin_lock(&root->inode_lock);
3966         while (*p) {
3967                 parent = *p;
3968                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
3969
3970                 if (ino < btrfs_ino(&entry->vfs_inode))
3971                         p = &parent->rb_left;
3972                 else if (ino > btrfs_ino(&entry->vfs_inode))
3973                         p = &parent->rb_right;
3974                 else {
3975                         WARN_ON(!(entry->vfs_inode.i_state &
3976                                   (I_WILL_FREE | I_FREEING)));
3977                         rb_erase(parent, &root->inode_tree);
3978                         RB_CLEAR_NODE(parent);
3979                         spin_unlock(&root->inode_lock);
3980                         goto again;
3981                 }
3982         }
3983         rb_link_node(&BTRFS_I(inode)->rb_node, parent, p);
3984         rb_insert_color(&BTRFS_I(inode)->rb_node, &root->inode_tree);
3985         spin_unlock(&root->inode_lock);
3986 }
3987
3988 static void inode_tree_del(struct inode *inode)
3989 {
3990         struct btrfs_root *root = BTRFS_I(inode)->root;
3991         int empty = 0;
3992
3993         spin_lock(&root->inode_lock);
3994         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
3995                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
3996                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
3997                 empty = RB_EMPTY_ROOT(&root->inode_tree);
3998         }
3999         spin_unlock(&root->inode_lock);
4000
4001         /*
4002          * Free space cache has inodes in the tree root, but the tree root has a
4003          * root_refs of 0, so this could end up dropping the tree root as a
4004          * snapshot, so we need the extra !root->fs_info->tree_root check to
4005          * make sure we don't drop it.
4006          */
4007         if (empty && btrfs_root_refs(&root->root_item) == 0 &&
4008             root != root->fs_info->tree_root) {
4009                 synchronize_srcu(&root->fs_info->subvol_srcu);
4010                 spin_lock(&root->inode_lock);
4011                 empty = RB_EMPTY_ROOT(&root->inode_tree);
4012                 spin_unlock(&root->inode_lock);
4013                 if (empty)
4014                         btrfs_add_dead_root(root);
4015         }
4016 }
4017
4018 void btrfs_invalidate_inodes(struct btrfs_root *root)
4019 {
4020         struct rb_node *node;
4021         struct rb_node *prev;
4022         struct btrfs_inode *entry;
4023         struct inode *inode;
4024         u64 objectid = 0;
4025
4026         WARN_ON(btrfs_root_refs(&root->root_item) != 0);
4027
4028         spin_lock(&root->inode_lock);
4029 again:
4030         node = root->inode_tree.rb_node;
4031         prev = NULL;
4032         while (node) {
4033                 prev = node;
4034                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4035
4036                 if (objectid < btrfs_ino(&entry->vfs_inode))
4037                         node = node->rb_left;
4038                 else if (objectid > btrfs_ino(&entry->vfs_inode))
4039                         node = node->rb_right;
4040                 else
4041                         break;
4042         }
4043         if (!node) {
4044                 while (prev) {
4045                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
4046                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
4047                                 node = prev;
4048                                 break;
4049                         }
4050                         prev = rb_next(prev);
4051                 }
4052         }
4053         while (node) {
4054                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4055                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
4056                 inode = igrab(&entry->vfs_inode);
4057                 if (inode) {
4058                         spin_unlock(&root->inode_lock);
4059                         if (atomic_read(&inode->i_count) > 1)
4060                                 d_prune_aliases(inode);
4061                         /*
4062                          * btrfs_drop_inode will have it removed from
4063                          * the inode cache when its usage count
4064                          * hits zero.
4065                          */
4066                         iput(inode);
4067                         cond_resched();
4068                         spin_lock(&root->inode_lock);
4069                         goto again;
4070                 }
4071
4072                 if (cond_resched_lock(&root->inode_lock))
4073                         goto again;
4074
4075                 node = rb_next(node);
4076         }
4077         spin_unlock(&root->inode_lock);
4078 }
4079
4080 static int btrfs_init_locked_inode(struct inode *inode, void *p)
4081 {
4082         struct btrfs_iget_args *args = p;
4083         inode->i_ino = args->ino;
4084         BTRFS_I(inode)->root = args->root;
4085         btrfs_set_inode_space_info(args->root, inode);
4086         return 0;
4087 }
4088
4089 static int btrfs_find_actor(struct inode *inode, void *opaque)
4090 {
4091         struct btrfs_iget_args *args = opaque;
4092         return args->ino == btrfs_ino(inode) &&
4093                 args->root == BTRFS_I(inode)->root;
4094 }
4095
4096 static struct inode *btrfs_iget_locked(struct super_block *s,
4097                                        u64 objectid,
4098                                        struct btrfs_root *root)
4099 {
4100         struct inode *inode;
4101         struct btrfs_iget_args args;
4102         args.ino = objectid;
4103         args.root = root;
4104
4105         inode = iget5_locked(s, objectid, btrfs_find_actor,
4106                              btrfs_init_locked_inode,
4107                              (void *)&args);
4108         return inode;
4109 }
4110
4111 /* Get an inode object given its location and corresponding root.
4112  * Returns in *is_new if the inode was read from disk
4113  */
4114 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
4115                          struct btrfs_root *root, int *new)
4116 {
4117         struct inode *inode;
4118
4119         inode = btrfs_iget_locked(s, location->objectid, root);
4120         if (!inode)
4121                 return ERR_PTR(-ENOMEM);
4122
4123         if (inode->i_state & I_NEW) {
4124                 BTRFS_I(inode)->root = root;
4125                 memcpy(&BTRFS_I(inode)->location, location, sizeof(*location));
4126                 btrfs_read_locked_inode(inode);
4127                 if (!is_bad_inode(inode)) {
4128                         inode_tree_add(inode);
4129                         unlock_new_inode(inode);
4130                         if (new)
4131                                 *new = 1;
4132                 } else {
4133                         unlock_new_inode(inode);
4134                         iput(inode);
4135                         inode = ERR_PTR(-ESTALE);
4136                 }
4137         }
4138
4139         return inode;
4140 }
4141
4142 static struct inode *new_simple_dir(struct super_block *s,
4143                                     struct btrfs_key *key,
4144                                     struct btrfs_root *root)
4145 {
4146         struct inode *inode = new_inode(s);
4147
4148         if (!inode)
4149                 return ERR_PTR(-ENOMEM);
4150
4151         BTRFS_I(inode)->root = root;
4152         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
4153         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
4154
4155         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
4156         inode->i_op = &btrfs_dir_ro_inode_operations;
4157         inode->i_fop = &simple_dir_operations;
4158         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
4159         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
4160
4161         return inode;
4162 }
4163
4164 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
4165 {
4166         struct inode *inode;
4167         struct btrfs_root *root = BTRFS_I(dir)->root;
4168         struct btrfs_root *sub_root = root;
4169         struct btrfs_key location;
4170         int index;
4171         int ret = 0;
4172
4173         if (dentry->d_name.len > BTRFS_NAME_LEN)
4174                 return ERR_PTR(-ENAMETOOLONG);
4175
4176         if (unlikely(d_need_lookup(dentry))) {
4177                 memcpy(&location, dentry->d_fsdata, sizeof(struct btrfs_key));
4178                 kfree(dentry->d_fsdata);
4179                 dentry->d_fsdata = NULL;
4180                 /* This thing is hashed, drop it for now */
4181                 d_drop(dentry);
4182         } else {
4183                 ret = btrfs_inode_by_name(dir, dentry, &location);
4184         }
4185
4186         if (ret < 0)
4187                 return ERR_PTR(ret);
4188
4189         if (location.objectid == 0)
4190                 return NULL;
4191
4192         if (location.type == BTRFS_INODE_ITEM_KEY) {
4193                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
4194                 return inode;
4195         }
4196
4197         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
4198
4199         index = srcu_read_lock(&root->fs_info->subvol_srcu);
4200         ret = fixup_tree_root_location(root, dir, dentry,
4201                                        &location, &sub_root);
4202         if (ret < 0) {
4203                 if (ret != -ENOENT)
4204                         inode = ERR_PTR(ret);
4205                 else
4206                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
4207         } else {
4208                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
4209         }
4210         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
4211
4212         if (!IS_ERR(inode) && root != sub_root) {
4213                 down_read(&root->fs_info->cleanup_work_sem);
4214                 if (!(inode->i_sb->s_flags & MS_RDONLY))
4215                         ret = btrfs_orphan_cleanup(sub_root);
4216                 up_read(&root->fs_info->cleanup_work_sem);
4217                 if (ret)
4218                         inode = ERR_PTR(ret);
4219         }
4220
4221         return inode;
4222 }
4223
4224 static int btrfs_dentry_delete(const struct dentry *dentry)
4225 {
4226         struct btrfs_root *root;
4227         struct inode *inode = dentry->d_inode;
4228
4229         if (!inode && !IS_ROOT(dentry))
4230                 inode = dentry->d_parent->d_inode;
4231
4232         if (inode) {
4233                 root = BTRFS_I(inode)->root;
4234                 if (btrfs_root_refs(&root->root_item) == 0)
4235                         return 1;
4236
4237                 if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
4238                         return 1;
4239         }
4240         return 0;
4241 }
4242
4243 static void btrfs_dentry_release(struct dentry *dentry)
4244 {
4245         if (dentry->d_fsdata)
4246                 kfree(dentry->d_fsdata);
4247 }
4248
4249 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
4250                                    struct nameidata *nd)
4251 {
4252         struct dentry *ret;
4253
4254         ret = d_splice_alias(btrfs_lookup_dentry(dir, dentry), dentry);
4255         if (unlikely(d_need_lookup(dentry))) {
4256                 spin_lock(&dentry->d_lock);
4257                 dentry->d_flags &= ~DCACHE_NEED_LOOKUP;
4258                 spin_unlock(&dentry->d_lock);
4259         }
4260         return ret;
4261 }
4262
4263 unsigned char btrfs_filetype_table[] = {
4264         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
4265 };
4266
4267 static int btrfs_real_readdir(struct file *filp, void *dirent,
4268                               filldir_t filldir)
4269 {
4270         struct inode *inode = filp->f_dentry->d_inode;
4271         struct btrfs_root *root = BTRFS_I(inode)->root;
4272         struct btrfs_item *item;
4273         struct btrfs_dir_item *di;
4274         struct btrfs_key key;
4275         struct btrfs_key found_key;
4276         struct btrfs_path *path;
4277         struct list_head ins_list;
4278         struct list_head del_list;
4279         int ret;
4280         struct extent_buffer *leaf;
4281         int slot;
4282         unsigned char d_type;
4283         int over = 0;
4284         u32 di_cur;
4285         u32 di_total;
4286         u32 di_len;
4287         int key_type = BTRFS_DIR_INDEX_KEY;
4288         char tmp_name[32];
4289         char *name_ptr;
4290         int name_len;
4291         int is_curr = 0;        /* filp->f_pos points to the current index? */
4292
4293         /* FIXME, use a real flag for deciding about the key type */
4294         if (root->fs_info->tree_root == root)
4295                 key_type = BTRFS_DIR_ITEM_KEY;
4296
4297         /* special case for "." */
4298         if (filp->f_pos == 0) {
4299                 over = filldir(dirent, ".", 1,
4300                                filp->f_pos, btrfs_ino(inode), DT_DIR);
4301                 if (over)
4302                         return 0;
4303                 filp->f_pos = 1;
4304         }
4305         /* special case for .., just use the back ref */
4306         if (filp->f_pos == 1) {
4307                 u64 pino = parent_ino(filp->f_path.dentry);
4308                 over = filldir(dirent, "..", 2,
4309                                filp->f_pos, pino, DT_DIR);
4310                 if (over)
4311                         return 0;
4312                 filp->f_pos = 2;
4313         }
4314         path = btrfs_alloc_path();
4315         if (!path)
4316                 return -ENOMEM;
4317
4318         path->reada = 1;
4319
4320         if (key_type == BTRFS_DIR_INDEX_KEY) {
4321                 INIT_LIST_HEAD(&ins_list);
4322                 INIT_LIST_HEAD(&del_list);
4323                 btrfs_get_delayed_items(inode, &ins_list, &del_list);
4324         }
4325
4326         btrfs_set_key_type(&key, key_type);
4327         key.offset = filp->f_pos;
4328         key.objectid = btrfs_ino(inode);
4329
4330         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4331         if (ret < 0)
4332                 goto err;
4333
4334         while (1) {
4335                 leaf = path->nodes[0];
4336                 slot = path->slots[0];
4337                 if (slot >= btrfs_header_nritems(leaf)) {
4338                         ret = btrfs_next_leaf(root, path);
4339                         if (ret < 0)
4340                                 goto err;
4341                         else if (ret > 0)
4342                                 break;
4343                         continue;
4344                 }
4345
4346                 item = btrfs_item_nr(leaf, slot);
4347                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
4348
4349                 if (found_key.objectid != key.objectid)
4350                         break;
4351                 if (btrfs_key_type(&found_key) != key_type)
4352                         break;
4353                 if (found_key.offset < filp->f_pos)
4354                         goto next;
4355                 if (key_type == BTRFS_DIR_INDEX_KEY &&
4356                     btrfs_should_delete_dir_index(&del_list,
4357                                                   found_key.offset))
4358                         goto next;
4359
4360                 filp->f_pos = found_key.offset;
4361                 is_curr = 1;
4362
4363                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
4364                 di_cur = 0;
4365                 di_total = btrfs_item_size(leaf, item);
4366
4367                 while (di_cur < di_total) {
4368                         struct btrfs_key location;
4369
4370                         if (verify_dir_item(root, leaf, di))
4371                                 break;
4372
4373                         name_len = btrfs_dir_name_len(leaf, di);
4374                         if (name_len <= sizeof(tmp_name)) {
4375                                 name_ptr = tmp_name;
4376                         } else {
4377                                 name_ptr = kmalloc(name_len, GFP_NOFS);
4378                                 if (!name_ptr) {
4379                                         ret = -ENOMEM;
4380                                         goto err;
4381                                 }
4382                         }
4383                         read_extent_buffer(leaf, name_ptr,
4384                                            (unsigned long)(di + 1), name_len);
4385
4386                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
4387                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
4388
4389
4390                         /* is this a reference to our own snapshot? If so
4391                          * skip it.
4392                          *
4393                          * In contrast to old kernels, we insert the snapshot's
4394                          * dir item and dir index after it has been created, so
4395                          * we won't find a reference to our own snapshot. We
4396                          * still keep the following code for backward
4397                          * compatibility.
4398                          */
4399                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
4400                             location.objectid == root->root_key.objectid) {
4401                                 over = 0;
4402                                 goto skip;
4403                         }
4404                         over = filldir(dirent, name_ptr, name_len,
4405                                        found_key.offset, location.objectid,
4406                                        d_type);
4407
4408 skip:
4409                         if (name_ptr != tmp_name)
4410                                 kfree(name_ptr);
4411
4412                         if (over)
4413                                 goto nopos;
4414                         di_len = btrfs_dir_name_len(leaf, di) +
4415                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
4416                         di_cur += di_len;
4417                         di = (struct btrfs_dir_item *)((char *)di + di_len);
4418                 }
4419 next:
4420                 path->slots[0]++;
4421         }
4422
4423         if (key_type == BTRFS_DIR_INDEX_KEY) {
4424                 if (is_curr)
4425                         filp->f_pos++;
4426                 ret = btrfs_readdir_delayed_dir_index(filp, dirent, filldir,
4427                                                       &ins_list);
4428                 if (ret)
4429                         goto nopos;
4430         }
4431
4432         /* Reached end of directory/root. Bump pos past the last item. */
4433         if (key_type == BTRFS_DIR_INDEX_KEY)
4434                 /*
4435                  * 32-bit glibc will use getdents64, but then strtol -
4436                  * so the last number we can serve is this.
4437                  */
4438                 filp->f_pos = 0x7fffffff;
4439         else
4440                 filp->f_pos++;
4441 nopos:
4442         ret = 0;
4443 err:
4444         if (key_type == BTRFS_DIR_INDEX_KEY)
4445                 btrfs_put_delayed_items(&ins_list, &del_list);
4446         btrfs_free_path(path);
4447         return ret;
4448 }
4449
4450 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
4451 {
4452         struct btrfs_root *root = BTRFS_I(inode)->root;
4453         struct btrfs_trans_handle *trans;
4454         int ret = 0;
4455         bool nolock = false;
4456
4457         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
4458                 return 0;
4459
4460         if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(inode))
4461                 nolock = true;
4462
4463         if (wbc->sync_mode == WB_SYNC_ALL) {
4464                 if (nolock)
4465                         trans = btrfs_join_transaction_nolock(root);
4466                 else
4467                         trans = btrfs_join_transaction(root);
4468                 if (IS_ERR(trans))
4469                         return PTR_ERR(trans);
4470                 if (nolock)
4471                         ret = btrfs_end_transaction_nolock(trans, root);
4472                 else
4473                         ret = btrfs_commit_transaction(trans, root);
4474         }
4475         return ret;
4476 }
4477
4478 /*
4479  * This is somewhat expensive, updating the tree every time the
4480  * inode changes.  But, it is most likely to find the inode in cache.
4481  * FIXME, needs more benchmarking...there are no reasons other than performance
4482  * to keep or drop this code.
4483  */
4484 int btrfs_dirty_inode(struct inode *inode)
4485 {
4486         struct btrfs_root *root = BTRFS_I(inode)->root;
4487         struct btrfs_trans_handle *trans;
4488         int ret;
4489
4490         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
4491                 return 0;
4492
4493         trans = btrfs_join_transaction(root);
4494         if (IS_ERR(trans))
4495                 return PTR_ERR(trans);
4496
4497         ret = btrfs_update_inode(trans, root, inode);
4498         if (ret && ret == -ENOSPC) {
4499                 /* whoops, lets try again with the full transaction */
4500                 btrfs_end_transaction(trans, root);
4501                 trans = btrfs_start_transaction(root, 1);
4502                 if (IS_ERR(trans))
4503                         return PTR_ERR(trans);
4504
4505                 ret = btrfs_update_inode(trans, root, inode);
4506         }
4507         btrfs_end_transaction(trans, root);
4508         if (BTRFS_I(inode)->delayed_node)
4509                 btrfs_balance_delayed_items(root);
4510
4511         return ret;
4512 }
4513
4514 /*
4515  * This is a copy of file_update_time.  We need this so we can return error on
4516  * ENOSPC for updating the inode in the case of file write and mmap writes.
4517  */
4518 static int btrfs_update_time(struct inode *inode, struct timespec *now,
4519                              int flags)
4520 {
4521         struct btrfs_root *root = BTRFS_I(inode)->root;
4522
4523         if (btrfs_root_readonly(root))
4524                 return -EROFS;
4525
4526         if (flags & S_VERSION)
4527                 inode_inc_iversion(inode);
4528         if (flags & S_CTIME)
4529                 inode->i_ctime = *now;
4530         if (flags & S_MTIME)
4531                 inode->i_mtime = *now;
4532         if (flags & S_ATIME)
4533                 inode->i_atime = *now;
4534         return btrfs_dirty_inode(inode);
4535 }
4536
4537 /*
4538  * find the highest existing sequence number in a directory
4539  * and then set the in-memory index_cnt variable to reflect
4540  * free sequence numbers
4541  */
4542 static int btrfs_set_inode_index_count(struct inode *inode)
4543 {
4544         struct btrfs_root *root = BTRFS_I(inode)->root;
4545         struct btrfs_key key, found_key;
4546         struct btrfs_path *path;
4547         struct extent_buffer *leaf;
4548         int ret;
4549
4550         key.objectid = btrfs_ino(inode);
4551         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
4552         key.offset = (u64)-1;
4553
4554         path = btrfs_alloc_path();
4555         if (!path)
4556                 return -ENOMEM;
4557
4558         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4559         if (ret < 0)
4560                 goto out;
4561         /* FIXME: we should be able to handle this */
4562         if (ret == 0)
4563                 goto out;
4564         ret = 0;
4565
4566         /*
4567          * MAGIC NUMBER EXPLANATION:
4568          * since we search a directory based on f_pos we have to start at 2
4569          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
4570          * else has to start at 2
4571          */
4572         if (path->slots[0] == 0) {
4573                 BTRFS_I(inode)->index_cnt = 2;
4574                 goto out;
4575         }
4576
4577         path->slots[0]--;
4578
4579         leaf = path->nodes[0];
4580         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4581
4582         if (found_key.objectid != btrfs_ino(inode) ||
4583             btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
4584                 BTRFS_I(inode)->index_cnt = 2;
4585                 goto out;
4586         }
4587
4588         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
4589 out:
4590         btrfs_free_path(path);
4591         return ret;
4592 }
4593
4594 /*
4595  * helper to find a free sequence number in a given directory.  This current
4596  * code is very simple, later versions will do smarter things in the btree
4597  */
4598 int btrfs_set_inode_index(struct inode *dir, u64 *index)
4599 {
4600         int ret = 0;
4601
4602         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
4603                 ret = btrfs_inode_delayed_dir_index_count(dir);
4604                 if (ret) {
4605                         ret = btrfs_set_inode_index_count(dir);
4606                         if (ret)
4607                                 return ret;
4608                 }
4609         }
4610
4611         *index = BTRFS_I(dir)->index_cnt;
4612         BTRFS_I(dir)->index_cnt++;
4613
4614         return ret;
4615 }
4616
4617 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
4618                                      struct btrfs_root *root,
4619                                      struct inode *dir,
4620                                      const char *name, int name_len,
4621                                      u64 ref_objectid, u64 objectid,
4622                                      umode_t mode, u64 *index)
4623 {
4624         struct inode *inode;
4625         struct btrfs_inode_item *inode_item;
4626         struct btrfs_key *location;
4627         struct btrfs_path *path;
4628         struct btrfs_inode_ref *ref;
4629         struct btrfs_key key[2];
4630         u32 sizes[2];
4631         unsigned long ptr;
4632         int ret;
4633         int owner;
4634
4635         path = btrfs_alloc_path();
4636         if (!path)
4637                 return ERR_PTR(-ENOMEM);
4638
4639         inode = new_inode(root->fs_info->sb);
4640         if (!inode) {
4641                 btrfs_free_path(path);
4642                 return ERR_PTR(-ENOMEM);
4643         }
4644
4645         /*
4646          * we have to initialize this early, so we can reclaim the inode
4647          * number if we fail afterwards in this function.
4648          */
4649         inode->i_ino = objectid;
4650
4651         if (dir) {
4652                 trace_btrfs_inode_request(dir);
4653
4654                 ret = btrfs_set_inode_index(dir, index);
4655                 if (ret) {
4656                         btrfs_free_path(path);
4657                         iput(inode);
4658                         return ERR_PTR(ret);
4659                 }
4660         }
4661         /*
4662          * index_cnt is ignored for everything but a dir,
4663          * btrfs_get_inode_index_count has an explanation for the magic
4664          * number
4665          */
4666         BTRFS_I(inode)->index_cnt = 2;
4667         BTRFS_I(inode)->root = root;
4668         BTRFS_I(inode)->generation = trans->transid;
4669         inode->i_generation = BTRFS_I(inode)->generation;
4670         btrfs_set_inode_space_info(root, inode);
4671
4672         if (S_ISDIR(mode))
4673                 owner = 0;
4674         else
4675                 owner = 1;
4676
4677         key[0].objectid = objectid;
4678         btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
4679         key[0].offset = 0;
4680
4681         key[1].objectid = objectid;
4682         btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
4683         key[1].offset = ref_objectid;
4684
4685         sizes[0] = sizeof(struct btrfs_inode_item);
4686         sizes[1] = name_len + sizeof(*ref);
4687
4688         path->leave_spinning = 1;
4689         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, 2);
4690         if (ret != 0)
4691                 goto fail;
4692
4693         inode_init_owner(inode, dir, mode);
4694         inode_set_bytes(inode, 0);
4695         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
4696         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
4697                                   struct btrfs_inode_item);
4698         fill_inode_item(trans, path->nodes[0], inode_item, inode);
4699
4700         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
4701                              struct btrfs_inode_ref);
4702         btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
4703         btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
4704         ptr = (unsigned long)(ref + 1);
4705         write_extent_buffer(path->nodes[0], name, ptr, name_len);
4706
4707         btrfs_mark_buffer_dirty(path->nodes[0]);
4708         btrfs_free_path(path);
4709
4710         location = &BTRFS_I(inode)->location;
4711         location->objectid = objectid;
4712         location->offset = 0;
4713         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
4714
4715         btrfs_inherit_iflags(inode, dir);
4716
4717         if (S_ISREG(mode)) {
4718                 if (btrfs_test_opt(root, NODATASUM))
4719                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
4720                 if (btrfs_test_opt(root, NODATACOW) ||
4721                     (BTRFS_I(dir)->flags & BTRFS_INODE_NODATACOW))
4722                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
4723         }
4724
4725         insert_inode_hash(inode);
4726         inode_tree_add(inode);
4727
4728         trace_btrfs_inode_new(inode);
4729         btrfs_set_inode_last_trans(trans, inode);
4730
4731         return inode;
4732 fail:
4733         if (dir)
4734                 BTRFS_I(dir)->index_cnt--;
4735         btrfs_free_path(path);
4736         iput(inode);
4737         return ERR_PTR(ret);
4738 }
4739
4740 static inline u8 btrfs_inode_type(struct inode *inode)
4741 {
4742         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
4743 }
4744
4745 /*
4746  * utility function to add 'inode' into 'parent_inode' with
4747  * a give name and a given sequence number.
4748  * if 'add_backref' is true, also insert a backref from the
4749  * inode to the parent directory.
4750  */
4751 int btrfs_add_link(struct btrfs_trans_handle *trans,
4752                    struct inode *parent_inode, struct inode *inode,
4753                    const char *name, int name_len, int add_backref, u64 index)
4754 {
4755         int ret = 0;
4756         struct btrfs_key key;
4757         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
4758         u64 ino = btrfs_ino(inode);
4759         u64 parent_ino = btrfs_ino(parent_inode);
4760
4761         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
4762                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
4763         } else {
4764                 key.objectid = ino;
4765                 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
4766                 key.offset = 0;
4767         }
4768
4769         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
4770                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
4771                                          key.objectid, root->root_key.objectid,
4772                                          parent_ino, index, name, name_len);
4773         } else if (add_backref) {
4774                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
4775                                              parent_ino, index);
4776         }
4777
4778         /* Nothing to clean up yet */
4779         if (ret)
4780                 return ret;
4781
4782         ret = btrfs_insert_dir_item(trans, root, name, name_len,
4783                                     parent_inode, &key,
4784                                     btrfs_inode_type(inode), index);
4785         if (ret == -EEXIST)
4786                 goto fail_dir_item;
4787         else if (ret) {
4788                 btrfs_abort_transaction(trans, root, ret);
4789                 return ret;
4790         }
4791
4792         btrfs_i_size_write(parent_inode, parent_inode->i_size +
4793                            name_len * 2);
4794         inode_inc_iversion(parent_inode);
4795         parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
4796         ret = btrfs_update_inode(trans, root, parent_inode);
4797         if (ret)
4798                 btrfs_abort_transaction(trans, root, ret);
4799         return ret;
4800
4801 fail_dir_item:
4802         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
4803                 u64 local_index;
4804                 int err;
4805                 err = btrfs_del_root_ref(trans, root->fs_info->tree_root,
4806                                  key.objectid, root->root_key.objectid,
4807                                  parent_ino, &local_index, name, name_len);
4808
4809         } else if (add_backref) {
4810                 u64 local_index;
4811                 int err;
4812
4813                 err = btrfs_del_inode_ref(trans, root, name, name_len,
4814                                           ino, parent_ino, &local_index);
4815         }
4816         return ret;
4817 }
4818
4819 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
4820                             struct inode *dir, struct dentry *dentry,
4821                             struct inode *inode, int backref, u64 index)
4822 {
4823         int err = btrfs_add_link(trans, dir, inode,
4824                                  dentry->d_name.name, dentry->d_name.len,
4825                                  backref, index);
4826         if (err > 0)
4827                 err = -EEXIST;
4828         return err;
4829 }
4830
4831 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
4832                         umode_t mode, dev_t rdev)
4833 {
4834         struct btrfs_trans_handle *trans;
4835         struct btrfs_root *root = BTRFS_I(dir)->root;
4836         struct inode *inode = NULL;
4837         int err;
4838         int drop_inode = 0;
4839         u64 objectid;
4840         unsigned long nr = 0;
4841         u64 index = 0;
4842
4843         if (!new_valid_dev(rdev))
4844                 return -EINVAL;
4845
4846         /*
4847          * 2 for inode item and ref
4848          * 2 for dir items
4849          * 1 for xattr if selinux is on
4850          */
4851         trans = btrfs_start_transaction(root, 5);
4852         if (IS_ERR(trans))
4853                 return PTR_ERR(trans);
4854
4855         err = btrfs_find_free_ino(root, &objectid);
4856         if (err)
4857                 goto out_unlock;
4858
4859         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4860                                 dentry->d_name.len, btrfs_ino(dir), objectid,
4861                                 mode, &index);
4862         if (IS_ERR(inode)) {
4863                 err = PTR_ERR(inode);
4864                 goto out_unlock;
4865         }
4866
4867         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4868         if (err) {
4869                 drop_inode = 1;
4870                 goto out_unlock;
4871         }
4872
4873         /*
4874         * If the active LSM wants to access the inode during
4875         * d_instantiate it needs these. Smack checks to see
4876         * if the filesystem supports xattrs by looking at the
4877         * ops vector.
4878         */
4879
4880         inode->i_op = &btrfs_special_inode_operations;
4881         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
4882         if (err)
4883                 drop_inode = 1;
4884         else {
4885                 init_special_inode(inode, inode->i_mode, rdev);
4886                 btrfs_update_inode(trans, root, inode);
4887                 d_instantiate(dentry, inode);
4888         }
4889 out_unlock:
4890         nr = trans->blocks_used;
4891         btrfs_end_transaction(trans, root);
4892         btrfs_btree_balance_dirty(root, nr);
4893         if (drop_inode) {
4894                 inode_dec_link_count(inode);
4895                 iput(inode);
4896         }
4897         return err;
4898 }
4899
4900 static int btrfs_create(struct inode *dir, struct dentry *dentry,
4901                         umode_t mode, struct nameidata *nd)
4902 {
4903         struct btrfs_trans_handle *trans;
4904         struct btrfs_root *root = BTRFS_I(dir)->root;
4905         struct inode *inode = NULL;
4906         int drop_inode = 0;
4907         int err;
4908         unsigned long nr = 0;
4909         u64 objectid;
4910         u64 index = 0;
4911
4912         /*
4913          * 2 for inode item and ref
4914          * 2 for dir items
4915          * 1 for xattr if selinux is on
4916          */
4917         trans = btrfs_start_transaction(root, 5);
4918         if (IS_ERR(trans))
4919                 return PTR_ERR(trans);
4920
4921         err = btrfs_find_free_ino(root, &objectid);
4922         if (err)
4923                 goto out_unlock;
4924
4925         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4926                                 dentry->d_name.len, btrfs_ino(dir), objectid,
4927                                 mode, &index);
4928         if (IS_ERR(inode)) {
4929                 err = PTR_ERR(inode);
4930                 goto out_unlock;
4931         }
4932
4933         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4934         if (err) {
4935                 drop_inode = 1;
4936                 goto out_unlock;
4937         }
4938
4939         /*
4940         * If the active LSM wants to access the inode during
4941         * d_instantiate it needs these. Smack checks to see
4942         * if the filesystem supports xattrs by looking at the
4943         * ops vector.
4944         */
4945         inode->i_fop = &btrfs_file_operations;
4946         inode->i_op = &btrfs_file_inode_operations;
4947
4948         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
4949         if (err)
4950                 drop_inode = 1;
4951         else {
4952                 inode->i_mapping->a_ops = &btrfs_aops;
4953                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
4954                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
4955                 d_instantiate(dentry, inode);
4956         }
4957 out_unlock:
4958         nr = trans->blocks_used;
4959         btrfs_end_transaction(trans, root);
4960         if (drop_inode) {
4961                 inode_dec_link_count(inode);
4962                 iput(inode);
4963         }
4964         btrfs_btree_balance_dirty(root, nr);
4965         return err;
4966 }
4967
4968 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
4969                       struct dentry *dentry)
4970 {
4971         struct btrfs_trans_handle *trans;
4972         struct btrfs_root *root = BTRFS_I(dir)->root;
4973         struct inode *inode = old_dentry->d_inode;
4974         u64 index;
4975         unsigned long nr = 0;
4976         int err;
4977         int drop_inode = 0;
4978
4979         /* do not allow sys_link's with other subvols of the same device */
4980         if (root->objectid != BTRFS_I(inode)->root->objectid)
4981                 return -EXDEV;
4982
4983         if (inode->i_nlink == ~0U)
4984                 return -EMLINK;
4985
4986         err = btrfs_set_inode_index(dir, &index);
4987         if (err)
4988                 goto fail;
4989
4990         /*
4991          * 2 items for inode and inode ref
4992          * 2 items for dir items
4993          * 1 item for parent inode
4994          */
4995         trans = btrfs_start_transaction(root, 5);
4996         if (IS_ERR(trans)) {
4997                 err = PTR_ERR(trans);
4998                 goto fail;
4999         }
5000
5001         btrfs_inc_nlink(inode);
5002         inode_inc_iversion(inode);
5003         inode->i_ctime = CURRENT_TIME;
5004         ihold(inode);
5005
5006         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
5007
5008         if (err) {
5009                 drop_inode = 1;
5010         } else {
5011                 struct dentry *parent = dentry->d_parent;
5012                 err = btrfs_update_inode(trans, root, inode);
5013                 if (err)
5014                         goto fail;
5015                 d_instantiate(dentry, inode);
5016                 btrfs_log_new_name(trans, inode, NULL, parent);
5017         }
5018
5019         nr = trans->blocks_used;
5020         btrfs_end_transaction(trans, root);
5021 fail:
5022         if (drop_inode) {
5023                 inode_dec_link_count(inode);
5024                 iput(inode);
5025         }
5026         btrfs_btree_balance_dirty(root, nr);
5027         return err;
5028 }
5029
5030 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
5031 {
5032         struct inode *inode = NULL;
5033         struct btrfs_trans_handle *trans;
5034         struct btrfs_root *root = BTRFS_I(dir)->root;
5035         int err = 0;
5036         int drop_on_err = 0;
5037         u64 objectid = 0;
5038         u64 index = 0;
5039         unsigned long nr = 1;
5040
5041         /*
5042          * 2 items for inode and ref
5043          * 2 items for dir items
5044          * 1 for xattr if selinux is on
5045          */
5046         trans = btrfs_start_transaction(root, 5);
5047         if (IS_ERR(trans))
5048                 return PTR_ERR(trans);
5049
5050         err = btrfs_find_free_ino(root, &objectid);
5051         if (err)
5052                 goto out_fail;
5053
5054         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5055                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5056                                 S_IFDIR | mode, &index);
5057         if (IS_ERR(inode)) {
5058                 err = PTR_ERR(inode);
5059                 goto out_fail;
5060         }
5061
5062         drop_on_err = 1;
5063
5064         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5065         if (err)
5066                 goto out_fail;
5067
5068         inode->i_op = &btrfs_dir_inode_operations;
5069         inode->i_fop = &btrfs_dir_file_operations;
5070
5071         btrfs_i_size_write(inode, 0);
5072         err = btrfs_update_inode(trans, root, inode);
5073         if (err)
5074                 goto out_fail;
5075
5076         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
5077                              dentry->d_name.len, 0, index);
5078         if (err)
5079                 goto out_fail;
5080
5081         d_instantiate(dentry, inode);
5082         drop_on_err = 0;
5083
5084 out_fail:
5085         nr = trans->blocks_used;
5086         btrfs_end_transaction(trans, root);
5087         if (drop_on_err)
5088                 iput(inode);
5089         btrfs_btree_balance_dirty(root, nr);
5090         return err;
5091 }
5092
5093 /* helper for btfs_get_extent.  Given an existing extent in the tree,
5094  * and an extent that you want to insert, deal with overlap and insert
5095  * the new extent into the tree.
5096  */
5097 static int merge_extent_mapping(struct extent_map_tree *em_tree,
5098                                 struct extent_map *existing,
5099                                 struct extent_map *em,
5100                                 u64 map_start, u64 map_len)
5101 {
5102         u64 start_diff;
5103
5104         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
5105         start_diff = map_start - em->start;
5106         em->start = map_start;
5107         em->len = map_len;
5108         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
5109             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
5110                 em->block_start += start_diff;
5111                 em->block_len -= start_diff;
5112         }
5113         return add_extent_mapping(em_tree, em);
5114 }
5115
5116 static noinline int uncompress_inline(struct btrfs_path *path,
5117                                       struct inode *inode, struct page *page,
5118                                       size_t pg_offset, u64 extent_offset,
5119                                       struct btrfs_file_extent_item *item)
5120 {
5121         int ret;
5122         struct extent_buffer *leaf = path->nodes[0];
5123         char *tmp;
5124         size_t max_size;
5125         unsigned long inline_size;
5126         unsigned long ptr;
5127         int compress_type;
5128
5129         WARN_ON(pg_offset != 0);
5130         compress_type = btrfs_file_extent_compression(leaf, item);
5131         max_size = btrfs_file_extent_ram_bytes(leaf, item);
5132         inline_size = btrfs_file_extent_inline_item_len(leaf,
5133                                         btrfs_item_nr(leaf, path->slots[0]));
5134         tmp = kmalloc(inline_size, GFP_NOFS);
5135         if (!tmp)
5136                 return -ENOMEM;
5137         ptr = btrfs_file_extent_inline_start(item);
5138
5139         read_extent_buffer(leaf, tmp, ptr, inline_size);
5140
5141         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
5142         ret = btrfs_decompress(compress_type, tmp, page,
5143                                extent_offset, inline_size, max_size);
5144         if (ret) {
5145                 char *kaddr = kmap_atomic(page);
5146                 unsigned long copy_size = min_t(u64,
5147                                   PAGE_CACHE_SIZE - pg_offset,
5148                                   max_size - extent_offset);
5149                 memset(kaddr + pg_offset, 0, copy_size);
5150                 kunmap_atomic(kaddr);
5151         }
5152         kfree(tmp);
5153         return 0;
5154 }
5155
5156 /*
5157  * a bit scary, this does extent mapping from logical file offset to the disk.
5158  * the ugly parts come from merging extents from the disk with the in-ram
5159  * representation.  This gets more complex because of the data=ordered code,
5160  * where the in-ram extents might be locked pending data=ordered completion.
5161  *
5162  * This also copies inline extents directly into the page.
5163  */
5164
5165 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
5166                                     size_t pg_offset, u64 start, u64 len,
5167                                     int create)
5168 {
5169         int ret;
5170         int err = 0;
5171         u64 bytenr;
5172         u64 extent_start = 0;
5173         u64 extent_end = 0;
5174         u64 objectid = btrfs_ino(inode);
5175         u32 found_type;
5176         struct btrfs_path *path = NULL;
5177         struct btrfs_root *root = BTRFS_I(inode)->root;
5178         struct btrfs_file_extent_item *item;
5179         struct extent_buffer *leaf;
5180         struct btrfs_key found_key;
5181         struct extent_map *em = NULL;
5182         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
5183         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
5184         struct btrfs_trans_handle *trans = NULL;
5185         int compress_type;
5186
5187 again:
5188         read_lock(&em_tree->lock);
5189         em = lookup_extent_mapping(em_tree, start, len);
5190         if (em)
5191                 em->bdev = root->fs_info->fs_devices->latest_bdev;
5192         read_unlock(&em_tree->lock);
5193
5194         if (em) {
5195                 if (em->start > start || em->start + em->len <= start)
5196                         free_extent_map(em);
5197                 else if (em->block_start == EXTENT_MAP_INLINE && page)
5198                         free_extent_map(em);
5199                 else
5200                         goto out;
5201         }
5202         em = alloc_extent_map();
5203         if (!em) {
5204                 err = -ENOMEM;
5205                 goto out;
5206         }
5207         em->bdev = root->fs_info->fs_devices->latest_bdev;
5208         em->start = EXTENT_MAP_HOLE;
5209         em->orig_start = EXTENT_MAP_HOLE;
5210         em->len = (u64)-1;
5211         em->block_len = (u64)-1;
5212
5213         if (!path) {
5214                 path = btrfs_alloc_path();
5215                 if (!path) {
5216                         err = -ENOMEM;
5217                         goto out;
5218                 }
5219                 /*
5220                  * Chances are we'll be called again, so go ahead and do
5221                  * readahead
5222                  */
5223                 path->reada = 1;
5224         }
5225
5226         ret = btrfs_lookup_file_extent(trans, root, path,
5227                                        objectid, start, trans != NULL);
5228         if (ret < 0) {
5229                 err = ret;
5230                 goto out;
5231         }
5232
5233         if (ret != 0) {
5234                 if (path->slots[0] == 0)
5235                         goto not_found;
5236                 path->slots[0]--;
5237         }
5238
5239         leaf = path->nodes[0];
5240         item = btrfs_item_ptr(leaf, path->slots[0],
5241                               struct btrfs_file_extent_item);
5242         /* are we inside the extent that was found? */
5243         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5244         found_type = btrfs_key_type(&found_key);
5245         if (found_key.objectid != objectid ||
5246             found_type != BTRFS_EXTENT_DATA_KEY) {
5247                 goto not_found;
5248         }
5249
5250         found_type = btrfs_file_extent_type(leaf, item);
5251         extent_start = found_key.offset;
5252         compress_type = btrfs_file_extent_compression(leaf, item);
5253         if (found_type == BTRFS_FILE_EXTENT_REG ||
5254             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
5255                 extent_end = extent_start +
5256                        btrfs_file_extent_num_bytes(leaf, item);
5257         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
5258                 size_t size;
5259                 size = btrfs_file_extent_inline_len(leaf, item);
5260                 extent_end = (extent_start + size + root->sectorsize - 1) &
5261                         ~((u64)root->sectorsize - 1);
5262         }
5263
5264         if (start >= extent_end) {
5265                 path->slots[0]++;
5266                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
5267                         ret = btrfs_next_leaf(root, path);
5268                         if (ret < 0) {
5269                                 err = ret;
5270                                 goto out;
5271                         }
5272                         if (ret > 0)
5273                                 goto not_found;
5274                         leaf = path->nodes[0];
5275                 }
5276                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5277                 if (found_key.objectid != objectid ||
5278                     found_key.type != BTRFS_EXTENT_DATA_KEY)
5279                         goto not_found;
5280                 if (start + len <= found_key.offset)
5281                         goto not_found;
5282                 em->start = start;
5283                 em->len = found_key.offset - start;
5284                 goto not_found_em;
5285         }
5286
5287         if (found_type == BTRFS_FILE_EXTENT_REG ||
5288             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
5289                 em->start = extent_start;
5290                 em->len = extent_end - extent_start;
5291                 em->orig_start = extent_start -
5292                                  btrfs_file_extent_offset(leaf, item);
5293                 bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
5294                 if (bytenr == 0) {
5295                         em->block_start = EXTENT_MAP_HOLE;
5296                         goto insert;
5297                 }
5298                 if (compress_type != BTRFS_COMPRESS_NONE) {
5299                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
5300                         em->compress_type = compress_type;
5301                         em->block_start = bytenr;
5302                         em->block_len = btrfs_file_extent_disk_num_bytes(leaf,
5303                                                                          item);
5304                 } else {
5305                         bytenr += btrfs_file_extent_offset(leaf, item);
5306                         em->block_start = bytenr;
5307                         em->block_len = em->len;
5308                         if (found_type == BTRFS_FILE_EXTENT_PREALLOC)
5309                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
5310                 }
5311                 goto insert;
5312         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
5313                 unsigned long ptr;
5314                 char *map;
5315                 size_t size;
5316                 size_t extent_offset;
5317                 size_t copy_size;
5318
5319                 em->block_start = EXTENT_MAP_INLINE;
5320                 if (!page || create) {
5321                         em->start = extent_start;
5322                         em->len = extent_end - extent_start;
5323                         goto out;
5324                 }
5325
5326                 size = btrfs_file_extent_inline_len(leaf, item);
5327                 extent_offset = page_offset(page) + pg_offset - extent_start;
5328                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
5329                                 size - extent_offset);
5330                 em->start = extent_start + extent_offset;
5331                 em->len = (copy_size + root->sectorsize - 1) &
5332                         ~((u64)root->sectorsize - 1);
5333                 em->orig_start = EXTENT_MAP_INLINE;
5334                 if (compress_type) {
5335                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
5336                         em->compress_type = compress_type;
5337                 }
5338                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
5339                 if (create == 0 && !PageUptodate(page)) {
5340                         if (btrfs_file_extent_compression(leaf, item) !=
5341                             BTRFS_COMPRESS_NONE) {
5342                                 ret = uncompress_inline(path, inode, page,
5343                                                         pg_offset,
5344                                                         extent_offset, item);
5345                                 BUG_ON(ret); /* -ENOMEM */
5346                         } else {
5347                                 map = kmap(page);
5348                                 read_extent_buffer(leaf, map + pg_offset, ptr,
5349                                                    copy_size);
5350                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
5351                                         memset(map + pg_offset + copy_size, 0,
5352                                                PAGE_CACHE_SIZE - pg_offset -
5353                                                copy_size);
5354                                 }
5355                                 kunmap(page);
5356                         }
5357                         flush_dcache_page(page);
5358                 } else if (create && PageUptodate(page)) {
5359                         BUG();
5360                         if (!trans) {
5361                                 kunmap(page);
5362                                 free_extent_map(em);
5363                                 em = NULL;
5364
5365                                 btrfs_release_path(path);
5366                                 trans = btrfs_join_transaction(root);
5367
5368                                 if (IS_ERR(trans))
5369                                         return ERR_CAST(trans);
5370                                 goto again;
5371                         }
5372                         map = kmap(page);
5373                         write_extent_buffer(leaf, map + pg_offset, ptr,
5374                                             copy_size);
5375                         kunmap(page);
5376                         btrfs_mark_buffer_dirty(leaf);
5377                 }
5378                 set_extent_uptodate(io_tree, em->start,
5379                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
5380                 goto insert;
5381         } else {
5382                 printk(KERN_ERR "btrfs unknown found_type %d\n", found_type);
5383                 WARN_ON(1);
5384         }
5385 not_found:
5386         em->start = start;
5387         em->len = len;
5388 not_found_em:
5389         em->block_start = EXTENT_MAP_HOLE;
5390         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
5391 insert:
5392         btrfs_release_path(path);
5393         if (em->start > start || extent_map_end(em) <= start) {
5394                 printk(KERN_ERR "Btrfs: bad extent! em: [%llu %llu] passed "
5395                        "[%llu %llu]\n", (unsigned long long)em->start,
5396                        (unsigned long long)em->len,
5397                        (unsigned long long)start,
5398                        (unsigned long long)len);
5399                 err = -EIO;
5400                 goto out;
5401         }
5402
5403         err = 0;
5404         write_lock(&em_tree->lock);
5405         ret = add_extent_mapping(em_tree, em);
5406         /* it is possible that someone inserted the extent into the tree
5407          * while we had the lock dropped.  It is also possible that
5408          * an overlapping map exists in the tree
5409          */
5410         if (ret == -EEXIST) {
5411                 struct extent_map *existing;
5412
5413                 ret = 0;
5414
5415                 existing = lookup_extent_mapping(em_tree, start, len);
5416                 if (existing && (existing->start > start ||
5417                     existing->start + existing->len <= start)) {
5418                         free_extent_map(existing);
5419                         existing = NULL;
5420                 }
5421                 if (!existing) {
5422                         existing = lookup_extent_mapping(em_tree, em->start,
5423                                                          em->len);
5424                         if (existing) {
5425                                 err = merge_extent_mapping(em_tree, existing,
5426                                                            em, start,
5427                                                            root->sectorsize);
5428                                 free_extent_map(existing);
5429                                 if (err) {
5430                                         free_extent_map(em);
5431                                         em = NULL;
5432                                 }
5433                         } else {
5434                                 err = -EIO;
5435                                 free_extent_map(em);
5436                                 em = NULL;
5437                         }
5438                 } else {
5439                         free_extent_map(em);
5440                         em = existing;
5441                         err = 0;
5442                 }
5443         }
5444         write_unlock(&em_tree->lock);
5445 out:
5446
5447         trace_btrfs_get_extent(root, em);
5448
5449         if (path)
5450                 btrfs_free_path(path);
5451         if (trans) {
5452                 ret = btrfs_end_transaction(trans, root);
5453                 if (!err)
5454                         err = ret;
5455         }
5456         if (err) {
5457                 free_extent_map(em);
5458                 return ERR_PTR(err);
5459         }
5460         BUG_ON(!em); /* Error is always set */
5461         return em;
5462 }
5463
5464 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
5465                                            size_t pg_offset, u64 start, u64 len,
5466                                            int create)
5467 {
5468         struct extent_map *em;
5469         struct extent_map *hole_em = NULL;
5470         u64 range_start = start;
5471         u64 end;
5472         u64 found;
5473         u64 found_end;
5474         int err = 0;
5475
5476         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
5477         if (IS_ERR(em))
5478                 return em;
5479         if (em) {
5480                 /*
5481                  * if our em maps to a hole, there might
5482                  * actually be delalloc bytes behind it
5483                  */
5484                 if (em->block_start != EXTENT_MAP_HOLE)
5485                         return em;
5486                 else
5487                         hole_em = em;
5488         }
5489
5490         /* check to see if we've wrapped (len == -1 or similar) */
5491         end = start + len;
5492         if (end < start)
5493                 end = (u64)-1;
5494         else
5495                 end -= 1;
5496
5497         em = NULL;
5498
5499         /* ok, we didn't find anything, lets look for delalloc */
5500         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
5501                                  end, len, EXTENT_DELALLOC, 1);
5502         found_end = range_start + found;
5503         if (found_end < range_start)
5504                 found_end = (u64)-1;
5505
5506         /*
5507          * we didn't find anything useful, return
5508          * the original results from get_extent()
5509          */
5510         if (range_start > end || found_end <= start) {
5511                 em = hole_em;
5512                 hole_em = NULL;
5513                 goto out;
5514         }
5515
5516         /* adjust the range_start to make sure it doesn't
5517          * go backwards from the start they passed in
5518          */
5519         range_start = max(start,range_start);
5520         found = found_end - range_start;
5521
5522         if (found > 0) {
5523                 u64 hole_start = start;
5524                 u64 hole_len = len;
5525
5526                 em = alloc_extent_map();
5527                 if (!em) {
5528                         err = -ENOMEM;
5529                         goto out;
5530                 }
5531                 /*
5532                  * when btrfs_get_extent can't find anything it
5533                  * returns one huge hole
5534                  *
5535                  * make sure what it found really fits our range, and
5536                  * adjust to make sure it is based on the start from
5537                  * the caller
5538                  */
5539                 if (hole_em) {
5540                         u64 calc_end = extent_map_end(hole_em);
5541
5542                         if (calc_end <= start || (hole_em->start > end)) {
5543                                 free_extent_map(hole_em);
5544                                 hole_em = NULL;
5545                         } else {
5546                                 hole_start = max(hole_em->start, start);
5547                                 hole_len = calc_end - hole_start;
5548                         }
5549                 }
5550                 em->bdev = NULL;
5551                 if (hole_em && range_start > hole_start) {
5552                         /* our hole starts before our delalloc, so we
5553                          * have to return just the parts of the hole
5554                          * that go until  the delalloc starts
5555                          */
5556                         em->len = min(hole_len,
5557                                       range_start - hole_start);
5558                         em->start = hole_start;
5559                         em->orig_start = hole_start;
5560                         /*
5561                          * don't adjust block start at all,
5562                          * it is fixed at EXTENT_MAP_HOLE
5563                          */
5564                         em->block_start = hole_em->block_start;
5565                         em->block_len = hole_len;
5566                 } else {
5567                         em->start = range_start;
5568                         em->len = found;
5569                         em->orig_start = range_start;
5570                         em->block_start = EXTENT_MAP_DELALLOC;
5571                         em->block_len = found;
5572                 }
5573         } else if (hole_em) {
5574                 return hole_em;
5575         }
5576 out:
5577
5578         free_extent_map(hole_em);
5579         if (err) {
5580                 free_extent_map(em);
5581                 return ERR_PTR(err);
5582         }
5583         return em;
5584 }
5585
5586 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
5587                                                   struct extent_map *em,
5588                                                   u64 start, u64 len)
5589 {
5590         struct btrfs_root *root = BTRFS_I(inode)->root;
5591       &nb