Btrfs: don't allocate a seperate csums array for direct reads
[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                 btrfs_update_root_times(trans, root);
2738
2739                 ret = btrfs_delayed_update_inode(trans, root, inode);
2740                 if (!ret)
2741                         btrfs_set_inode_last_trans(trans, inode);
2742                 return ret;
2743         }
2744
2745         return btrfs_update_inode_item(trans, root, inode);
2746 }
2747
2748 static noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
2749                                 struct btrfs_root *root, struct inode *inode)
2750 {
2751         int ret;
2752
2753         ret = btrfs_update_inode(trans, root, inode);
2754         if (ret == -ENOSPC)
2755                 return btrfs_update_inode_item(trans, root, inode);
2756         return ret;
2757 }
2758
2759 /*
2760  * unlink helper that gets used here in inode.c and in the tree logging
2761  * recovery code.  It remove a link in a directory with a given name, and
2762  * also drops the back refs in the inode to the directory
2763  */
2764 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2765                                 struct btrfs_root *root,
2766                                 struct inode *dir, struct inode *inode,
2767                                 const char *name, int name_len)
2768 {
2769         struct btrfs_path *path;
2770         int ret = 0;
2771         struct extent_buffer *leaf;
2772         struct btrfs_dir_item *di;
2773         struct btrfs_key key;
2774         u64 index;
2775         u64 ino = btrfs_ino(inode);
2776         u64 dir_ino = btrfs_ino(dir);
2777
2778         path = btrfs_alloc_path();
2779         if (!path) {
2780                 ret = -ENOMEM;
2781                 goto out;
2782         }
2783
2784         path->leave_spinning = 1;
2785         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
2786                                     name, name_len, -1);
2787         if (IS_ERR(di)) {
2788                 ret = PTR_ERR(di);
2789                 goto err;
2790         }
2791         if (!di) {
2792                 ret = -ENOENT;
2793                 goto err;
2794         }
2795         leaf = path->nodes[0];
2796         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2797         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2798         if (ret)
2799                 goto err;
2800         btrfs_release_path(path);
2801
2802         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
2803                                   dir_ino, &index);
2804         if (ret) {
2805                 printk(KERN_INFO "btrfs failed to delete reference to %.*s, "
2806                        "inode %llu parent %llu\n", name_len, name,
2807                        (unsigned long long)ino, (unsigned long long)dir_ino);
2808                 btrfs_abort_transaction(trans, root, ret);
2809                 goto err;
2810         }
2811
2812         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
2813         if (ret) {
2814                 btrfs_abort_transaction(trans, root, ret);
2815                 goto err;
2816         }
2817
2818         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
2819                                          inode, dir_ino);
2820         if (ret != 0 && ret != -ENOENT) {
2821                 btrfs_abort_transaction(trans, root, ret);
2822                 goto err;
2823         }
2824
2825         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
2826                                            dir, index);
2827         if (ret == -ENOENT)
2828                 ret = 0;
2829 err:
2830         btrfs_free_path(path);
2831         if (ret)
2832                 goto out;
2833
2834         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
2835         inode_inc_iversion(inode);
2836         inode_inc_iversion(dir);
2837         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
2838         ret = btrfs_update_inode(trans, root, dir);
2839 out:
2840         return ret;
2841 }
2842
2843 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2844                        struct btrfs_root *root,
2845                        struct inode *dir, struct inode *inode,
2846                        const char *name, int name_len)
2847 {
2848         int ret;
2849         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
2850         if (!ret) {
2851                 btrfs_drop_nlink(inode);
2852                 ret = btrfs_update_inode(trans, root, inode);
2853         }
2854         return ret;
2855 }
2856                 
2857
2858 /* helper to check if there is any shared block in the path */
2859 static int check_path_shared(struct btrfs_root *root,
2860                              struct btrfs_path *path)
2861 {
2862         struct extent_buffer *eb;
2863         int level;
2864         u64 refs = 1;
2865
2866         for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2867                 int ret;
2868
2869                 if (!path->nodes[level])
2870                         break;
2871                 eb = path->nodes[level];
2872                 if (!btrfs_block_can_be_shared(root, eb))
2873                         continue;
2874                 ret = btrfs_lookup_extent_info(NULL, root, eb->start, eb->len,
2875                                                &refs, NULL);
2876                 if (refs > 1)
2877                         return 1;
2878         }
2879         return 0;
2880 }
2881
2882 /*
2883  * helper to start transaction for unlink and rmdir.
2884  *
2885  * unlink and rmdir are special in btrfs, they do not always free space.
2886  * so in enospc case, we should make sure they will free space before
2887  * allowing them to use the global metadata reservation.
2888  */
2889 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir,
2890                                                        struct dentry *dentry)
2891 {
2892         struct btrfs_trans_handle *trans;
2893         struct btrfs_root *root = BTRFS_I(dir)->root;
2894         struct btrfs_path *path;
2895         struct btrfs_inode_ref *ref;
2896         struct btrfs_dir_item *di;
2897         struct inode *inode = dentry->d_inode;
2898         u64 index;
2899         int check_link = 1;
2900         int err = -ENOSPC;
2901         int ret;
2902         u64 ino = btrfs_ino(inode);
2903         u64 dir_ino = btrfs_ino(dir);
2904
2905         /*
2906          * 1 for the possible orphan item
2907          * 1 for the dir item
2908          * 1 for the dir index
2909          * 1 for the inode ref
2910          * 1 for the inode ref in the tree log
2911          * 2 for the dir entries in the log
2912          * 1 for the inode
2913          */
2914         trans = btrfs_start_transaction(root, 8);
2915         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
2916                 return trans;
2917
2918         if (ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
2919                 return ERR_PTR(-ENOSPC);
2920
2921         /* check if there is someone else holds reference */
2922         if (S_ISDIR(inode->i_mode) && atomic_read(&inode->i_count) > 1)
2923                 return ERR_PTR(-ENOSPC);
2924
2925         if (atomic_read(&inode->i_count) > 2)
2926                 return ERR_PTR(-ENOSPC);
2927
2928         if (xchg(&root->fs_info->enospc_unlink, 1))
2929                 return ERR_PTR(-ENOSPC);
2930
2931         path = btrfs_alloc_path();
2932         if (!path) {
2933                 root->fs_info->enospc_unlink = 0;
2934                 return ERR_PTR(-ENOMEM);
2935         }
2936
2937         /* 1 for the orphan item */
2938         trans = btrfs_start_transaction(root, 1);
2939         if (IS_ERR(trans)) {
2940                 btrfs_free_path(path);
2941                 root->fs_info->enospc_unlink = 0;
2942                 return trans;
2943         }
2944
2945         path->skip_locking = 1;
2946         path->search_commit_root = 1;
2947
2948         ret = btrfs_lookup_inode(trans, root, path,
2949                                 &BTRFS_I(dir)->location, 0);
2950         if (ret < 0) {
2951                 err = ret;
2952                 goto out;
2953         }
2954         if (ret == 0) {
2955                 if (check_path_shared(root, path))
2956                         goto out;
2957         } else {
2958                 check_link = 0;
2959         }
2960         btrfs_release_path(path);
2961
2962         ret = btrfs_lookup_inode(trans, root, path,
2963                                 &BTRFS_I(inode)->location, 0);
2964         if (ret < 0) {
2965                 err = ret;
2966                 goto out;
2967         }
2968         if (ret == 0) {
2969                 if (check_path_shared(root, path))
2970                         goto out;
2971         } else {
2972                 check_link = 0;
2973         }
2974         btrfs_release_path(path);
2975
2976         if (ret == 0 && S_ISREG(inode->i_mode)) {
2977                 ret = btrfs_lookup_file_extent(trans, root, path,
2978                                                ino, (u64)-1, 0);
2979                 if (ret < 0) {
2980                         err = ret;
2981                         goto out;
2982                 }
2983                 BUG_ON(ret == 0); /* Corruption */
2984                 if (check_path_shared(root, path))
2985                         goto out;
2986                 btrfs_release_path(path);
2987         }
2988
2989         if (!check_link) {
2990                 err = 0;
2991                 goto out;
2992         }
2993
2994         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
2995                                 dentry->d_name.name, dentry->d_name.len, 0);
2996         if (IS_ERR(di)) {
2997                 err = PTR_ERR(di);
2998                 goto out;
2999         }
3000         if (di) {
3001                 if (check_path_shared(root, path))
3002                         goto out;
3003         } else {
3004                 err = 0;
3005                 goto out;
3006         }
3007         btrfs_release_path(path);
3008
3009         ref = btrfs_lookup_inode_ref(trans, root, path,
3010                                 dentry->d_name.name, dentry->d_name.len,
3011                                 ino, dir_ino, 0);
3012         if (IS_ERR(ref)) {
3013                 err = PTR_ERR(ref);
3014                 goto out;
3015         }
3016         BUG_ON(!ref); /* Logic error */
3017         if (check_path_shared(root, path))
3018                 goto out;
3019         index = btrfs_inode_ref_index(path->nodes[0], ref);
3020         btrfs_release_path(path);
3021
3022         /*
3023          * This is a commit root search, if we can lookup inode item and other
3024          * relative items in the commit root, it means the transaction of
3025          * dir/file creation has been committed, and the dir index item that we
3026          * delay to insert has also been inserted into the commit root. So
3027          * we needn't worry about the delayed insertion of the dir index item
3028          * here.
3029          */
3030         di = btrfs_lookup_dir_index_item(trans, root, path, dir_ino, index,
3031                                 dentry->d_name.name, dentry->d_name.len, 0);
3032         if (IS_ERR(di)) {
3033                 err = PTR_ERR(di);
3034                 goto out;
3035         }
3036         BUG_ON(ret == -ENOENT);
3037         if (check_path_shared(root, path))
3038                 goto out;
3039
3040         err = 0;
3041 out:
3042         btrfs_free_path(path);
3043         /* Migrate the orphan reservation over */
3044         if (!err)
3045                 err = btrfs_block_rsv_migrate(trans->block_rsv,
3046                                 &root->fs_info->global_block_rsv,
3047                                 trans->bytes_reserved);
3048
3049         if (err) {
3050                 btrfs_end_transaction(trans, root);
3051                 root->fs_info->enospc_unlink = 0;
3052                 return ERR_PTR(err);
3053         }
3054
3055         trans->block_rsv = &root->fs_info->global_block_rsv;
3056         return trans;
3057 }
3058
3059 static void __unlink_end_trans(struct btrfs_trans_handle *trans,
3060                                struct btrfs_root *root)
3061 {
3062         if (trans->block_rsv == &root->fs_info->global_block_rsv) {
3063                 btrfs_block_rsv_release(root, trans->block_rsv,
3064                                         trans->bytes_reserved);
3065                 trans->block_rsv = &root->fs_info->trans_block_rsv;
3066                 BUG_ON(!root->fs_info->enospc_unlink);
3067                 root->fs_info->enospc_unlink = 0;
3068         }
3069         btrfs_end_transaction(trans, root);
3070 }
3071
3072 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
3073 {
3074         struct btrfs_root *root = BTRFS_I(dir)->root;
3075         struct btrfs_trans_handle *trans;
3076         struct inode *inode = dentry->d_inode;
3077         int ret;
3078         unsigned long nr = 0;
3079
3080         trans = __unlink_start_trans(dir, dentry);
3081         if (IS_ERR(trans))
3082                 return PTR_ERR(trans);
3083
3084         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
3085
3086         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3087                                  dentry->d_name.name, dentry->d_name.len);
3088         if (ret)
3089                 goto out;
3090
3091         if (inode->i_nlink == 0) {
3092                 ret = btrfs_orphan_add(trans, inode);
3093                 if (ret)
3094                         goto out;
3095         }
3096
3097 out:
3098         nr = trans->blocks_used;
3099         __unlink_end_trans(trans, root);
3100         btrfs_btree_balance_dirty(root, nr);
3101         return ret;
3102 }
3103
3104 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
3105                         struct btrfs_root *root,
3106                         struct inode *dir, u64 objectid,
3107                         const char *name, int name_len)
3108 {
3109         struct btrfs_path *path;
3110         struct extent_buffer *leaf;
3111         struct btrfs_dir_item *di;
3112         struct btrfs_key key;
3113         u64 index;
3114         int ret;
3115         u64 dir_ino = btrfs_ino(dir);
3116
3117         path = btrfs_alloc_path();
3118         if (!path)
3119                 return -ENOMEM;
3120
3121         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3122                                    name, name_len, -1);
3123         if (IS_ERR_OR_NULL(di)) {
3124                 if (!di)
3125                         ret = -ENOENT;
3126                 else
3127                         ret = PTR_ERR(di);
3128                 goto out;
3129         }
3130
3131         leaf = path->nodes[0];
3132         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3133         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3134         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3135         if (ret) {
3136                 btrfs_abort_transaction(trans, root, ret);
3137                 goto out;
3138         }
3139         btrfs_release_path(path);
3140
3141         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
3142                                  objectid, root->root_key.objectid,
3143                                  dir_ino, &index, name, name_len);
3144         if (ret < 0) {
3145                 if (ret != -ENOENT) {
3146                         btrfs_abort_transaction(trans, root, ret);
3147                         goto out;
3148                 }
3149                 di = btrfs_search_dir_index_item(root, path, dir_ino,
3150                                                  name, name_len);
3151                 if (IS_ERR_OR_NULL(di)) {
3152                         if (!di)
3153                                 ret = -ENOENT;
3154                         else
3155                                 ret = PTR_ERR(di);
3156                         btrfs_abort_transaction(trans, root, ret);
3157                         goto out;
3158                 }
3159
3160                 leaf = path->nodes[0];
3161                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3162                 btrfs_release_path(path);
3163                 index = key.offset;
3164         }
3165         btrfs_release_path(path);
3166
3167         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3168         if (ret) {
3169                 btrfs_abort_transaction(trans, root, ret);
3170                 goto out;
3171         }
3172
3173         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3174         inode_inc_iversion(dir);
3175         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3176         ret = btrfs_update_inode(trans, root, dir);
3177         if (ret)
3178                 btrfs_abort_transaction(trans, root, ret);
3179 out:
3180         btrfs_free_path(path);
3181         return ret;
3182 }
3183
3184 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
3185 {
3186         struct inode *inode = dentry->d_inode;
3187         int err = 0;
3188         struct btrfs_root *root = BTRFS_I(dir)->root;
3189         struct btrfs_trans_handle *trans;
3190         unsigned long nr = 0;
3191
3192         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE ||
3193             btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
3194                 return -ENOTEMPTY;
3195
3196         trans = __unlink_start_trans(dir, dentry);
3197         if (IS_ERR(trans))
3198                 return PTR_ERR(trans);
3199
3200         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
3201                 err = btrfs_unlink_subvol(trans, root, dir,
3202                                           BTRFS_I(inode)->location.objectid,
3203                                           dentry->d_name.name,
3204                                           dentry->d_name.len);
3205                 goto out;
3206         }
3207
3208         err = btrfs_orphan_add(trans, inode);
3209         if (err)
3210                 goto out;
3211
3212         /* now the directory is empty */
3213         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3214                                  dentry->d_name.name, dentry->d_name.len);
3215         if (!err)
3216                 btrfs_i_size_write(inode, 0);
3217 out:
3218         nr = trans->blocks_used;
3219         __unlink_end_trans(trans, root);
3220         btrfs_btree_balance_dirty(root, nr);
3221
3222         return err;
3223 }
3224
3225 /*
3226  * this can truncate away extent items, csum items and directory items.
3227  * It starts at a high offset and removes keys until it can't find
3228  * any higher than new_size
3229  *
3230  * csum items that cross the new i_size are truncated to the new size
3231  * as well.
3232  *
3233  * min_type is the minimum key type to truncate down to.  If set to 0, this
3234  * will kill all the items on this inode, including the INODE_ITEM_KEY.
3235  */
3236 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
3237                                struct btrfs_root *root,
3238                                struct inode *inode,
3239                                u64 new_size, u32 min_type)
3240 {
3241         struct btrfs_path *path;
3242         struct extent_buffer *leaf;
3243         struct btrfs_file_extent_item *fi;
3244         struct btrfs_key key;
3245         struct btrfs_key found_key;
3246         u64 extent_start = 0;
3247         u64 extent_num_bytes = 0;
3248         u64 extent_offset = 0;
3249         u64 item_end = 0;
3250         u64 mask = root->sectorsize - 1;
3251         u32 found_type = (u8)-1;
3252         int found_extent;
3253         int del_item;
3254         int pending_del_nr = 0;
3255         int pending_del_slot = 0;
3256         int extent_type = -1;
3257         int ret;
3258         int err = 0;
3259         u64 ino = btrfs_ino(inode);
3260
3261         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
3262
3263         path = btrfs_alloc_path();
3264         if (!path)
3265                 return -ENOMEM;
3266         path->reada = -1;
3267
3268         if (root->ref_cows || root == root->fs_info->tree_root)
3269                 btrfs_drop_extent_cache(inode, new_size & (~mask), (u64)-1, 0);
3270
3271         /*
3272          * This function is also used to drop the items in the log tree before
3273          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
3274          * it is used to drop the loged items. So we shouldn't kill the delayed
3275          * items.
3276          */
3277         if (min_type == 0 && root == BTRFS_I(inode)->root)
3278                 btrfs_kill_delayed_inode_items(inode);
3279
3280         key.objectid = ino;
3281         key.offset = (u64)-1;
3282         key.type = (u8)-1;
3283
3284 search_again:
3285         path->leave_spinning = 1;
3286         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3287         if (ret < 0) {
3288                 err = ret;
3289                 goto out;
3290         }
3291
3292         if (ret > 0) {
3293                 /* there are no items in the tree for us to truncate, we're
3294                  * done
3295                  */
3296                 if (path->slots[0] == 0)
3297                         goto out;
3298                 path->slots[0]--;
3299         }
3300
3301         while (1) {
3302                 fi = NULL;
3303                 leaf = path->nodes[0];
3304                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3305                 found_type = btrfs_key_type(&found_key);
3306
3307                 if (found_key.objectid != ino)
3308                         break;
3309
3310                 if (found_type < min_type)
3311                         break;
3312
3313                 item_end = found_key.offset;
3314                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
3315                         fi = btrfs_item_ptr(leaf, path->slots[0],
3316                                             struct btrfs_file_extent_item);
3317                         extent_type = btrfs_file_extent_type(leaf, fi);
3318                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3319                                 item_end +=
3320                                     btrfs_file_extent_num_bytes(leaf, fi);
3321                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3322                                 item_end += btrfs_file_extent_inline_len(leaf,
3323                                                                          fi);
3324                         }
3325                         item_end--;
3326                 }
3327                 if (found_type > min_type) {
3328                         del_item = 1;
3329                 } else {
3330                         if (item_end < new_size)
3331                                 break;
3332                         if (found_key.offset >= new_size)
3333                                 del_item = 1;
3334                         else
3335                                 del_item = 0;
3336                 }
3337                 found_extent = 0;
3338                 /* FIXME, shrink the extent if the ref count is only 1 */
3339                 if (found_type != BTRFS_EXTENT_DATA_KEY)
3340                         goto delete;
3341
3342                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3343                         u64 num_dec;
3344                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
3345                         if (!del_item) {
3346                                 u64 orig_num_bytes =
3347                                         btrfs_file_extent_num_bytes(leaf, fi);
3348                                 extent_num_bytes = new_size -
3349                                         found_key.offset + root->sectorsize - 1;
3350                                 extent_num_bytes = extent_num_bytes &
3351                                         ~((u64)root->sectorsize - 1);
3352                                 btrfs_set_file_extent_num_bytes(leaf, fi,
3353                                                          extent_num_bytes);
3354                                 num_dec = (orig_num_bytes -
3355                                            extent_num_bytes);
3356                                 if (root->ref_cows && extent_start != 0)
3357                                         inode_sub_bytes(inode, num_dec);
3358                                 btrfs_mark_buffer_dirty(leaf);
3359                         } else {
3360                                 extent_num_bytes =
3361                                         btrfs_file_extent_disk_num_bytes(leaf,
3362                                                                          fi);
3363                                 extent_offset = found_key.offset -
3364                                         btrfs_file_extent_offset(leaf, fi);
3365
3366                                 /* FIXME blocksize != 4096 */
3367                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
3368                                 if (extent_start != 0) {
3369                                         found_extent = 1;
3370                                         if (root->ref_cows)
3371                                                 inode_sub_bytes(inode, num_dec);
3372                                 }
3373                         }
3374                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3375                         /*
3376                          * we can't truncate inline items that have had
3377                          * special encodings
3378                          */
3379                         if (!del_item &&
3380                             btrfs_file_extent_compression(leaf, fi) == 0 &&
3381                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
3382                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
3383                                 u32 size = new_size - found_key.offset;
3384
3385                                 if (root->ref_cows) {
3386                                         inode_sub_bytes(inode, item_end + 1 -
3387                                                         new_size);
3388                                 }
3389                                 size =
3390                                     btrfs_file_extent_calc_inline_size(size);
3391                                 btrfs_truncate_item(trans, root, path,
3392                                                     size, 1);
3393                         } else if (root->ref_cows) {
3394                                 inode_sub_bytes(inode, item_end + 1 -
3395                                                 found_key.offset);
3396                         }
3397                 }
3398 delete:
3399                 if (del_item) {
3400                         if (!pending_del_nr) {
3401                                 /* no pending yet, add ourselves */
3402                                 pending_del_slot = path->slots[0];
3403                                 pending_del_nr = 1;
3404                         } else if (pending_del_nr &&
3405                                    path->slots[0] + 1 == pending_del_slot) {
3406                                 /* hop on the pending chunk */
3407                                 pending_del_nr++;
3408                                 pending_del_slot = path->slots[0];
3409                         } else {
3410                                 BUG();
3411                         }
3412                 } else {
3413                         break;
3414                 }
3415                 if (found_extent && (root->ref_cows ||
3416                                      root == root->fs_info->tree_root)) {
3417                         btrfs_set_path_blocking(path);
3418                         ret = btrfs_free_extent(trans, root, extent_start,
3419                                                 extent_num_bytes, 0,
3420                                                 btrfs_header_owner(leaf),
3421                                                 ino, extent_offset, 0);
3422                         BUG_ON(ret);
3423                 }
3424
3425                 if (found_type == BTRFS_INODE_ITEM_KEY)
3426                         break;
3427
3428                 if (path->slots[0] == 0 ||
3429                     path->slots[0] != pending_del_slot) {
3430                         if (root->ref_cows &&
3431                             BTRFS_I(inode)->location.objectid !=
3432                                                 BTRFS_FREE_INO_OBJECTID) {
3433                                 err = -EAGAIN;
3434                                 goto out;
3435                         }
3436                         if (pending_del_nr) {
3437                                 ret = btrfs_del_items(trans, root, path,
3438                                                 pending_del_slot,
3439                                                 pending_del_nr);
3440                                 if (ret) {
3441                                         btrfs_abort_transaction(trans,
3442                                                                 root, ret);
3443                                         goto error;
3444                                 }
3445                                 pending_del_nr = 0;
3446                         }
3447                         btrfs_release_path(path);
3448                         goto search_again;
3449                 } else {
3450                         path->slots[0]--;
3451                 }
3452         }
3453 out:
3454         if (pending_del_nr) {
3455                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
3456                                       pending_del_nr);
3457                 if (ret)
3458                         btrfs_abort_transaction(trans, root, ret);
3459         }
3460 error:
3461         btrfs_free_path(path);
3462         return err;
3463 }
3464
3465 /*
3466  * taken from block_truncate_page, but does cow as it zeros out
3467  * any bytes left in the last page in the file.
3468  */
3469 static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
3470 {
3471         struct inode *inode = mapping->host;
3472         struct btrfs_root *root = BTRFS_I(inode)->root;
3473         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3474         struct btrfs_ordered_extent *ordered;
3475         struct extent_state *cached_state = NULL;
3476         char *kaddr;
3477         u32 blocksize = root->sectorsize;
3478         pgoff_t index = from >> PAGE_CACHE_SHIFT;
3479         unsigned offset = from & (PAGE_CACHE_SIZE-1);
3480         struct page *page;
3481         gfp_t mask = btrfs_alloc_write_mask(mapping);
3482         int ret = 0;
3483         u64 page_start;
3484         u64 page_end;
3485
3486         if ((offset & (blocksize - 1)) == 0)
3487                 goto out;
3488         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
3489         if (ret)
3490                 goto out;
3491
3492         ret = -ENOMEM;
3493 again:
3494         page = find_or_create_page(mapping, index, mask);
3495         if (!page) {
3496                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
3497                 goto out;
3498         }
3499
3500         page_start = page_offset(page);
3501         page_end = page_start + PAGE_CACHE_SIZE - 1;
3502
3503         if (!PageUptodate(page)) {
3504                 ret = btrfs_readpage(NULL, page);
3505                 lock_page(page);
3506                 if (page->mapping != mapping) {
3507                         unlock_page(page);
3508                         page_cache_release(page);
3509                         goto again;
3510                 }
3511                 if (!PageUptodate(page)) {
3512                         ret = -EIO;
3513                         goto out_unlock;
3514                 }
3515         }
3516         wait_on_page_writeback(page);
3517
3518         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
3519         set_page_extent_mapped(page);
3520
3521         ordered = btrfs_lookup_ordered_extent(inode, page_start);
3522         if (ordered) {
3523                 unlock_extent_cached(io_tree, page_start, page_end,
3524                                      &cached_state, GFP_NOFS);
3525                 unlock_page(page);
3526                 page_cache_release(page);
3527                 btrfs_start_ordered_extent(inode, ordered, 1);
3528                 btrfs_put_ordered_extent(ordered);
3529                 goto again;
3530         }
3531
3532         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
3533                           EXTENT_DIRTY | EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING,
3534                           0, 0, &cached_state, GFP_NOFS);
3535
3536         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
3537                                         &cached_state);
3538         if (ret) {
3539                 unlock_extent_cached(io_tree, page_start, page_end,
3540                                      &cached_state, GFP_NOFS);
3541                 goto out_unlock;
3542         }
3543
3544         ret = 0;
3545         if (offset != PAGE_CACHE_SIZE) {
3546                 kaddr = kmap(page);
3547                 memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
3548                 flush_dcache_page(page);
3549                 kunmap(page);
3550         }
3551         ClearPageChecked(page);
3552         set_page_dirty(page);
3553         unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
3554                              GFP_NOFS);
3555
3556 out_unlock:
3557         if (ret)
3558                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
3559         unlock_page(page);
3560         page_cache_release(page);
3561 out:
3562         return ret;
3563 }
3564
3565 /*
3566  * This function puts in dummy file extents for the area we're creating a hole
3567  * for.  So if we are truncating this file to a larger size we need to insert
3568  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
3569  * the range between oldsize and size
3570  */
3571 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
3572 {
3573         struct btrfs_trans_handle *trans;
3574         struct btrfs_root *root = BTRFS_I(inode)->root;
3575         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3576         struct extent_map *em = NULL;
3577         struct extent_state *cached_state = NULL;
3578         u64 mask = root->sectorsize - 1;
3579         u64 hole_start = (oldsize + mask) & ~mask;
3580         u64 block_end = (size + mask) & ~mask;
3581         u64 last_byte;
3582         u64 cur_offset;
3583         u64 hole_size;
3584         int err = 0;
3585
3586         if (size <= hole_start)
3587                 return 0;
3588
3589         while (1) {
3590                 struct btrfs_ordered_extent *ordered;
3591                 btrfs_wait_ordered_range(inode, hole_start,
3592                                          block_end - hole_start);
3593                 lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
3594                                  &cached_state);
3595                 ordered = btrfs_lookup_ordered_extent(inode, hole_start);
3596                 if (!ordered)
3597                         break;
3598                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
3599                                      &cached_state, GFP_NOFS);
3600                 btrfs_put_ordered_extent(ordered);
3601         }
3602
3603         cur_offset = hole_start;
3604         while (1) {
3605                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
3606                                 block_end - cur_offset, 0);
3607                 if (IS_ERR(em)) {
3608                         err = PTR_ERR(em);
3609                         break;
3610                 }
3611                 last_byte = min(extent_map_end(em), block_end);
3612                 last_byte = (last_byte + mask) & ~mask;
3613                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
3614                         u64 hint_byte = 0;
3615                         hole_size = last_byte - cur_offset;
3616
3617                         trans = btrfs_start_transaction(root, 3);
3618                         if (IS_ERR(trans)) {
3619                                 err = PTR_ERR(trans);
3620                                 break;
3621                         }
3622
3623                         err = btrfs_drop_extents(trans, inode, cur_offset,
3624                                                  cur_offset + hole_size,
3625                                                  &hint_byte, 1);
3626                         if (err) {
3627                                 btrfs_abort_transaction(trans, root, err);
3628                                 btrfs_end_transaction(trans, root);
3629                                 break;
3630                         }
3631
3632                         err = btrfs_insert_file_extent(trans, root,
3633                                         btrfs_ino(inode), cur_offset, 0,
3634                                         0, hole_size, 0, hole_size,
3635                                         0, 0, 0);
3636                         if (err) {
3637                                 btrfs_abort_transaction(trans, root, err);
3638                                 btrfs_end_transaction(trans, root);
3639                                 break;
3640                         }
3641
3642                         btrfs_drop_extent_cache(inode, hole_start,
3643                                         last_byte - 1, 0);
3644
3645                         btrfs_update_inode(trans, root, inode);
3646                         btrfs_end_transaction(trans, root);
3647                 }
3648                 free_extent_map(em);
3649                 em = NULL;
3650                 cur_offset = last_byte;
3651                 if (cur_offset >= block_end)
3652                         break;
3653         }
3654
3655         free_extent_map(em);
3656         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
3657                              GFP_NOFS);
3658         return err;
3659 }
3660
3661 static int btrfs_setsize(struct inode *inode, loff_t newsize)
3662 {
3663         struct btrfs_root *root = BTRFS_I(inode)->root;
3664         struct btrfs_trans_handle *trans;
3665         loff_t oldsize = i_size_read(inode);
3666         int ret;
3667
3668         if (newsize == oldsize)
3669                 return 0;
3670
3671         if (newsize > oldsize) {
3672                 truncate_pagecache(inode, oldsize, newsize);
3673                 ret = btrfs_cont_expand(inode, oldsize, newsize);
3674                 if (ret)
3675                         return ret;
3676
3677                 trans = btrfs_start_transaction(root, 1);
3678                 if (IS_ERR(trans))
3679                         return PTR_ERR(trans);
3680
3681                 i_size_write(inode, newsize);
3682                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
3683                 ret = btrfs_update_inode(trans, root, inode);
3684                 btrfs_end_transaction(trans, root);
3685         } else {
3686
3687                 /*
3688                  * We're truncating a file that used to have good data down to
3689                  * zero. Make sure it gets into the ordered flush list so that
3690                  * any new writes get down to disk quickly.
3691                  */
3692                 if (newsize == 0)
3693                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
3694                                 &BTRFS_I(inode)->runtime_flags);
3695
3696                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
3697                 truncate_setsize(inode, newsize);
3698                 ret = btrfs_truncate(inode);
3699         }
3700
3701         return ret;
3702 }
3703
3704 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
3705 {
3706         struct inode *inode = dentry->d_inode;
3707         struct btrfs_root *root = BTRFS_I(inode)->root;
3708         int err;
3709
3710         if (btrfs_root_readonly(root))
3711                 return -EROFS;
3712
3713         err = inode_change_ok(inode, attr);
3714         if (err)
3715                 return err;
3716
3717         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
3718                 err = btrfs_setsize(inode, attr->ia_size);
3719                 if (err)
3720                         return err;
3721         }
3722
3723         if (attr->ia_valid) {
3724                 setattr_copy(inode, attr);
3725                 inode_inc_iversion(inode);
3726                 err = btrfs_dirty_inode(inode);
3727
3728                 if (!err && attr->ia_valid & ATTR_MODE)
3729                         err = btrfs_acl_chmod(inode);
3730         }
3731
3732         return err;
3733 }
3734
3735 void btrfs_evict_inode(struct inode *inode)
3736 {
3737         struct btrfs_trans_handle *trans;
3738         struct btrfs_root *root = BTRFS_I(inode)->root;
3739         struct btrfs_block_rsv *rsv, *global_rsv;
3740         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
3741         unsigned long nr;
3742         int ret;
3743
3744         trace_btrfs_inode_evict(inode);
3745
3746         truncate_inode_pages(&inode->i_data, 0);
3747         if (inode->i_nlink && (btrfs_root_refs(&root->root_item) != 0 ||
3748                                btrfs_is_free_space_inode(inode)))
3749                 goto no_delete;
3750
3751         if (is_bad_inode(inode)) {
3752                 btrfs_orphan_del(NULL, inode);
3753                 goto no_delete;
3754         }
3755         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
3756         btrfs_wait_ordered_range(inode, 0, (u64)-1);
3757
3758         if (root->fs_info->log_root_recovering) {
3759                 BUG_ON(test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3760                                  &BTRFS_I(inode)->runtime_flags));
3761                 goto no_delete;
3762         }
3763
3764         if (inode->i_nlink > 0) {
3765                 BUG_ON(btrfs_root_refs(&root->root_item) != 0);
3766                 goto no_delete;
3767         }
3768
3769         rsv = btrfs_alloc_block_rsv(root);
3770         if (!rsv) {
3771                 btrfs_orphan_del(NULL, inode);
3772                 goto no_delete;
3773         }
3774         rsv->size = min_size;
3775         global_rsv = &root->fs_info->global_block_rsv;
3776
3777         btrfs_i_size_write(inode, 0);
3778
3779         /*
3780          * This is a bit simpler than btrfs_truncate since
3781          *
3782          * 1) We've already reserved our space for our orphan item in the
3783          *    unlink.
3784          * 2) We're going to delete the inode item, so we don't need to update
3785          *    it at all.
3786          *
3787          * So we just need to reserve some slack space in case we add bytes when
3788          * doing the truncate.
3789          */
3790         while (1) {
3791                 ret = btrfs_block_rsv_refill_noflush(root, rsv, min_size);
3792
3793                 /*
3794                  * Try and steal from the global reserve since we will
3795                  * likely not use this space anyway, we want to try as
3796                  * hard as possible to get this to work.
3797                  */
3798                 if (ret)
3799                         ret = btrfs_block_rsv_migrate(global_rsv, rsv, min_size);
3800
3801                 if (ret) {
3802                         printk(KERN_WARNING "Could not get space for a "
3803                                "delete, will truncate on mount %d\n", ret);
3804                         btrfs_orphan_del(NULL, inode);
3805                         btrfs_free_block_rsv(root, rsv);
3806                         goto no_delete;
3807                 }
3808
3809                 trans = btrfs_start_transaction(root, 0);
3810                 if (IS_ERR(trans)) {
3811                         btrfs_orphan_del(NULL, inode);
3812                         btrfs_free_block_rsv(root, rsv);
3813                         goto no_delete;
3814                 }
3815
3816                 trans->block_rsv = rsv;
3817
3818                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
3819                 if (ret != -EAGAIN)
3820                         break;
3821
3822                 nr = trans->blocks_used;
3823                 btrfs_end_transaction(trans, root);
3824                 trans = NULL;
3825                 btrfs_btree_balance_dirty(root, nr);
3826         }
3827
3828         btrfs_free_block_rsv(root, rsv);
3829
3830         if (ret == 0) {
3831                 trans->block_rsv = root->orphan_block_rsv;
3832                 ret = btrfs_orphan_del(trans, inode);
3833                 BUG_ON(ret);
3834         }
3835
3836         trans->block_rsv = &root->fs_info->trans_block_rsv;
3837         if (!(root == root->fs_info->tree_root ||
3838               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
3839                 btrfs_return_ino(root, btrfs_ino(inode));
3840
3841         nr = trans->blocks_used;
3842         btrfs_end_transaction(trans, root);
3843         btrfs_btree_balance_dirty(root, nr);
3844 no_delete:
3845         clear_inode(inode);
3846         return;
3847 }
3848
3849 /*
3850  * this returns the key found in the dir entry in the location pointer.
3851  * If no dir entries were found, location->objectid is 0.
3852  */
3853 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
3854                                struct btrfs_key *location)
3855 {
3856         const char *name = dentry->d_name.name;
3857         int namelen = dentry->d_name.len;
3858         struct btrfs_dir_item *di;
3859         struct btrfs_path *path;
3860         struct btrfs_root *root = BTRFS_I(dir)->root;
3861         int ret = 0;
3862
3863         path = btrfs_alloc_path();
3864         if (!path)
3865                 return -ENOMEM;
3866
3867         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
3868                                     namelen, 0);
3869         if (IS_ERR(di))
3870                 ret = PTR_ERR(di);
3871
3872         if (IS_ERR_OR_NULL(di))
3873                 goto out_err;
3874
3875         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
3876 out:
3877         btrfs_free_path(path);
3878         return ret;
3879 out_err:
3880         location->objectid = 0;
3881         goto out;
3882 }
3883
3884 /*
3885  * when we hit a tree root in a directory, the btrfs part of the inode
3886  * needs to be changed to reflect the root directory of the tree root.  This
3887  * is kind of like crossing a mount point.
3888  */
3889 static int fixup_tree_root_location(struct btrfs_root *root,
3890                                     struct inode *dir,
3891                                     struct dentry *dentry,
3892                                     struct btrfs_key *location,
3893                                     struct btrfs_root **sub_root)
3894 {
3895         struct btrfs_path *path;
3896         struct btrfs_root *new_root;
3897         struct btrfs_root_ref *ref;
3898         struct extent_buffer *leaf;
3899         int ret;
3900         int err = 0;
3901
3902         path = btrfs_alloc_path();
3903         if (!path) {
3904                 err = -ENOMEM;
3905                 goto out;
3906         }
3907
3908         err = -ENOENT;
3909         ret = btrfs_find_root_ref(root->fs_info->tree_root, path,
3910                                   BTRFS_I(dir)->root->root_key.objectid,
3911                                   location->objectid);
3912         if (ret) {
3913                 if (ret < 0)
3914                         err = ret;
3915                 goto out;
3916         }
3917
3918         leaf = path->nodes[0];
3919         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
3920         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
3921             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
3922                 goto out;
3923
3924         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
3925                                    (unsigned long)(ref + 1),
3926                                    dentry->d_name.len);
3927         if (ret)
3928                 goto out;
3929
3930         btrfs_release_path(path);
3931
3932         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
3933         if (IS_ERR(new_root)) {
3934                 err = PTR_ERR(new_root);
3935                 goto out;
3936         }
3937
3938         if (btrfs_root_refs(&new_root->root_item) == 0) {
3939                 err = -ENOENT;
3940                 goto out;
3941         }
3942
3943         *sub_root = new_root;
3944         location->objectid = btrfs_root_dirid(&new_root->root_item);
3945         location->type = BTRFS_INODE_ITEM_KEY;
3946         location->offset = 0;
3947         err = 0;
3948 out:
3949         btrfs_free_path(path);
3950         return err;
3951 }
3952
3953 static void inode_tree_add(struct inode *inode)
3954 {
3955         struct btrfs_root *root = BTRFS_I(inode)->root;
3956         struct btrfs_inode *entry;
3957         struct rb_node **p;
3958         struct rb_node *parent;
3959         u64 ino = btrfs_ino(inode);
3960 again:
3961         p = &root->inode_tree.rb_node;
3962         parent = NULL;
3963
3964         if (inode_unhashed(inode))
3965                 return;
3966
3967         spin_lock(&root->inode_lock);
3968         while (*p) {
3969                 parent = *p;
3970                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
3971
3972                 if (ino < btrfs_ino(&entry->vfs_inode))
3973                         p = &parent->rb_left;
3974                 else if (ino > btrfs_ino(&entry->vfs_inode))
3975                         p = &parent->rb_right;
3976                 else {
3977                         WARN_ON(!(entry->vfs_inode.i_state &
3978                                   (I_WILL_FREE | I_FREEING)));
3979                         rb_erase(parent, &root->inode_tree);
3980                         RB_CLEAR_NODE(parent);
3981                         spin_unlock(&root->inode_lock);
3982                         goto again;
3983                 }
3984         }
3985         rb_link_node(&BTRFS_I(inode)->rb_node, parent, p);
3986         rb_insert_color(&BTRFS_I(inode)->rb_node, &root->inode_tree);
3987         spin_unlock(&root->inode_lock);
3988 }
3989
3990 static void inode_tree_del(struct inode *inode)
3991 {
3992         struct btrfs_root *root = BTRFS_I(inode)->root;
3993         int empty = 0;
3994
3995         spin_lock(&root->inode_lock);
3996         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
3997                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
3998                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
3999                 empty = RB_EMPTY_ROOT(&root->inode_tree);
4000         }
4001         spin_unlock(&root->inode_lock);
4002
4003         /*
4004          * Free space cache has inodes in the tree root, but the tree root has a
4005          * root_refs of 0, so this could end up dropping the tree root as a
4006          * snapshot, so we need the extra !root->fs_info->tree_root check to
4007          * make sure we don't drop it.
4008          */
4009         if (empty && btrfs_root_refs(&root->root_item) == 0 &&
4010             root != root->fs_info->tree_root) {
4011                 synchronize_srcu(&root->fs_info->subvol_srcu);
4012                 spin_lock(&root->inode_lock);
4013                 empty = RB_EMPTY_ROOT(&root->inode_tree);
4014                 spin_unlock(&root->inode_lock);
4015                 if (empty)
4016                         btrfs_add_dead_root(root);
4017         }
4018 }
4019
4020 void btrfs_invalidate_inodes(struct btrfs_root *root)
4021 {
4022         struct rb_node *node;
4023         struct rb_node *prev;
4024         struct btrfs_inode *entry;
4025         struct inode *inode;
4026         u64 objectid = 0;
4027
4028         WARN_ON(btrfs_root_refs(&root->root_item) != 0);
4029
4030         spin_lock(&root->inode_lock);
4031 again:
4032         node = root->inode_tree.rb_node;
4033         prev = NULL;
4034         while (node) {
4035                 prev = node;
4036                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4037
4038                 if (objectid < btrfs_ino(&entry->vfs_inode))
4039                         node = node->rb_left;
4040                 else if (objectid > btrfs_ino(&entry->vfs_inode))
4041                         node = node->rb_right;
4042                 else
4043                         break;
4044         }
4045         if (!node) {
4046                 while (prev) {
4047                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
4048                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
4049                                 node = prev;
4050                                 break;
4051                         }
4052                         prev = rb_next(prev);
4053                 }
4054         }
4055         while (node) {
4056                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4057                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
4058                 inode = igrab(&entry->vfs_inode);
4059                 if (inode) {
4060                         spin_unlock(&root->inode_lock);
4061                         if (atomic_read(&inode->i_count) > 1)
4062                                 d_prune_aliases(inode);
4063                         /*
4064                          * btrfs_drop_inode will have it removed from
4065                          * the inode cache when its usage count
4066                          * hits zero.
4067                          */
4068                         iput(inode);
4069                         cond_resched();
4070                         spin_lock(&root->inode_lock);
4071                         goto again;
4072                 }
4073
4074                 if (cond_resched_lock(&root->inode_lock))
4075                         goto again;
4076
4077                 node = rb_next(node);
4078         }
4079         spin_unlock(&root->inode_lock);
4080 }
4081
4082 static int btrfs_init_locked_inode(struct inode *inode, void *p)
4083 {
4084         struct btrfs_iget_args *args = p;
4085         inode->i_ino = args->ino;
4086         BTRFS_I(inode)->root = args->root;
4087         return 0;
4088 }
4089
4090 static int btrfs_find_actor(struct inode *inode, void *opaque)
4091 {
4092         struct btrfs_iget_args *args = opaque;
4093         return args->ino == btrfs_ino(inode) &&
4094                 args->root == BTRFS_I(inode)->root;
4095 }
4096
4097 static struct inode *btrfs_iget_locked(struct super_block *s,
4098                                        u64 objectid,
4099                                        struct btrfs_root *root)
4100 {
4101         struct inode *inode;
4102         struct btrfs_iget_args args;
4103         args.ino = objectid;
4104         args.root = root;
4105
4106         inode = iget5_locked(s, objectid, btrfs_find_actor,
4107                              btrfs_init_locked_inode,
4108                              (void *)&args);
4109         return inode;
4110 }
4111
4112 /* Get an inode object given its location and corresponding root.
4113  * Returns in *is_new if the inode was read from disk
4114  */
4115 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
4116                          struct btrfs_root *root, int *new)
4117 {
4118         struct inode *inode;
4119
4120         inode = btrfs_iget_locked(s, location->objectid, root);
4121         if (!inode)
4122                 return ERR_PTR(-ENOMEM);
4123
4124         if (inode->i_state & I_NEW) {
4125                 BTRFS_I(inode)->root = root;
4126                 memcpy(&BTRFS_I(inode)->location, location, sizeof(*location));
4127                 btrfs_read_locked_inode(inode);
4128                 if (!is_bad_inode(inode)) {
4129                         inode_tree_add(inode);
4130                         unlock_new_inode(inode);
4131                         if (new)
4132                                 *new = 1;
4133                 } else {
4134                         unlock_new_inode(inode);
4135                         iput(inode);
4136                         inode = ERR_PTR(-ESTALE);
4137                 }
4138         }
4139
4140         return inode;
4141 }
4142
4143 static struct inode *new_simple_dir(struct super_block *s,
4144                                     struct btrfs_key *key,
4145                                     struct btrfs_root *root)
4146 {
4147         struct inode *inode = new_inode(s);
4148
4149         if (!inode)
4150                 return ERR_PTR(-ENOMEM);
4151
4152         BTRFS_I(inode)->root = root;
4153         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
4154         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
4155
4156         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
4157         inode->i_op = &btrfs_dir_ro_inode_operations;
4158         inode->i_fop = &simple_dir_operations;
4159         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
4160         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
4161
4162         return inode;
4163 }
4164
4165 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
4166 {
4167         struct inode *inode;
4168         struct btrfs_root *root = BTRFS_I(dir)->root;
4169         struct btrfs_root *sub_root = root;
4170         struct btrfs_key location;
4171         int index;
4172         int ret = 0;
4173
4174         if (dentry->d_name.len > BTRFS_NAME_LEN)
4175                 return ERR_PTR(-ENAMETOOLONG);
4176
4177         if (unlikely(d_need_lookup(dentry))) {
4178                 memcpy(&location, dentry->d_fsdata, sizeof(struct btrfs_key));
4179                 kfree(dentry->d_fsdata);
4180                 dentry->d_fsdata = NULL;
4181                 /* This thing is hashed, drop it for now */
4182                 d_drop(dentry);
4183         } else {
4184                 ret = btrfs_inode_by_name(dir, dentry, &location);
4185         }
4186
4187         if (ret < 0)
4188                 return ERR_PTR(ret);
4189
4190         if (location.objectid == 0)
4191                 return NULL;
4192
4193         if (location.type == BTRFS_INODE_ITEM_KEY) {
4194                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
4195                 return inode;
4196         }
4197
4198         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
4199
4200         index = srcu_read_lock(&root->fs_info->subvol_srcu);
4201         ret = fixup_tree_root_location(root, dir, dentry,
4202                                        &location, &sub_root);
4203         if (ret < 0) {
4204                 if (ret != -ENOENT)
4205                         inode = ERR_PTR(ret);
4206                 else
4207                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
4208         } else {
4209                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
4210         }
4211         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
4212
4213         if (!IS_ERR(inode) && root != sub_root) {
4214                 down_read(&root->fs_info->cleanup_work_sem);
4215                 if (!(inode->i_sb->s_flags & MS_RDONLY))
4216                         ret = btrfs_orphan_cleanup(sub_root);
4217                 up_read(&root->fs_info->cleanup_work_sem);
4218                 if (ret)
4219                         inode = ERR_PTR(ret);
4220         }
4221
4222         return inode;
4223 }
4224
4225 static int btrfs_dentry_delete(const struct dentry *dentry)
4226 {
4227         struct btrfs_root *root;
4228         struct inode *inode = dentry->d_inode;
4229
4230         if (!inode && !IS_ROOT(dentry))
4231                 inode = dentry->d_parent->d_inode;
4232
4233         if (inode) {
4234                 root = BTRFS_I(inode)->root;
4235                 if (btrfs_root_refs(&root->root_item) == 0)
4236                         return 1;
4237
4238                 if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
4239                         return 1;
4240         }
4241         return 0;
4242 }
4243
4244 static void btrfs_dentry_release(struct dentry *dentry)
4245 {
4246         if (dentry->d_fsdata)
4247                 kfree(dentry->d_fsdata);
4248 }
4249
4250 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
4251                                    struct nameidata *nd)
4252 {
4253         struct dentry *ret;
4254
4255         ret = d_splice_alias(btrfs_lookup_dentry(dir, dentry), dentry);
4256         if (unlikely(d_need_lookup(dentry))) {
4257                 spin_lock(&dentry->d_lock);
4258                 dentry->d_flags &= ~DCACHE_NEED_LOOKUP;
4259                 spin_unlock(&dentry->d_lock);
4260         }
4261         return ret;
4262 }
4263
4264 unsigned char btrfs_filetype_table[] = {
4265         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
4266 };
4267
4268 static int btrfs_real_readdir(struct file *filp, void *dirent,
4269                               filldir_t filldir)
4270 {
4271         struct inode *inode = filp->f_dentry->d_inode;
4272         struct btrfs_root *root = BTRFS_I(inode)->root;
4273         struct btrfs_item *item;
4274         struct btrfs_dir_item *di;
4275         struct btrfs_key key;
4276         struct btrfs_key found_key;
4277         struct btrfs_path *path;
4278         struct list_head ins_list;
4279         struct list_head del_list;
4280         int ret;
4281         struct extent_buffer *leaf;
4282         int slot;
4283         unsigned char d_type;
4284         int over = 0;
4285         u32 di_cur;
4286         u32 di_total;
4287         u32 di_len;
4288         int key_type = BTRFS_DIR_INDEX_KEY;
4289         char tmp_name[32];
4290         char *name_ptr;
4291         int name_len;
4292         int is_curr = 0;        /* filp->f_pos points to the current index? */
4293
4294         /* FIXME, use a real flag for deciding about the key type */
4295         if (root->fs_info->tree_root == root)
4296                 key_type = BTRFS_DIR_ITEM_KEY;
4297
4298         /* special case for "." */
4299         if (filp->f_pos == 0) {
4300                 over = filldir(dirent, ".", 1,
4301                                filp->f_pos, btrfs_ino(inode), DT_DIR);
4302                 if (over)
4303                         return 0;
4304                 filp->f_pos = 1;
4305         }
4306         /* special case for .., just use the back ref */
4307         if (filp->f_pos == 1) {
4308                 u64 pino = parent_ino(filp->f_path.dentry);
4309                 over = filldir(dirent, "..", 2,
4310                                filp->f_pos, pino, DT_DIR);
4311                 if (over)
4312                         return 0;
4313                 filp->f_pos = 2;
4314         }
4315         path = btrfs_alloc_path();
4316         if (!path)
4317                 return -ENOMEM;
4318
4319         path->reada = 1;
4320
4321         if (key_type == BTRFS_DIR_INDEX_KEY) {
4322                 INIT_LIST_HEAD(&ins_list);
4323                 INIT_LIST_HEAD(&del_list);
4324                 btrfs_get_delayed_items(inode, &ins_list, &del_list);
4325         }
4326
4327         btrfs_set_key_type(&key, key_type);
4328         key.offset = filp->f_pos;
4329         key.objectid = btrfs_ino(inode);
4330
4331         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4332         if (ret < 0)
4333                 goto err;
4334
4335         while (1) {
4336                 leaf = path->nodes[0];
4337                 slot = path->slots[0];
4338                 if (slot >= btrfs_header_nritems(leaf)) {
4339                         ret = btrfs_next_leaf(root, path);
4340                         if (ret < 0)
4341                                 goto err;
4342                         else if (ret > 0)
4343                                 break;
4344                         continue;
4345                 }
4346
4347                 item = btrfs_item_nr(leaf, slot);
4348                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
4349
4350                 if (found_key.objectid != key.objectid)
4351                         break;
4352                 if (btrfs_key_type(&found_key) != key_type)
4353                         break;
4354                 if (found_key.offset < filp->f_pos)
4355                         goto next;
4356                 if (key_type == BTRFS_DIR_INDEX_KEY &&
4357                     btrfs_should_delete_dir_index(&del_list,
4358                                                   found_key.offset))
4359                         goto next;
4360
4361                 filp->f_pos = found_key.offset;
4362                 is_curr = 1;
4363
4364                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
4365                 di_cur = 0;
4366                 di_total = btrfs_item_size(leaf, item);
4367
4368                 while (di_cur < di_total) {
4369                         struct btrfs_key location;
4370
4371                         if (verify_dir_item(root, leaf, di))
4372                                 break;
4373
4374                         name_len = btrfs_dir_name_len(leaf, di);
4375                         if (name_len <= sizeof(tmp_name)) {
4376                                 name_ptr = tmp_name;
4377                         } else {
4378                                 name_ptr = kmalloc(name_len, GFP_NOFS);
4379                                 if (!name_ptr) {
4380                                         ret = -ENOMEM;
4381                                         goto err;
4382                                 }
4383                         }
4384                         read_extent_buffer(leaf, name_ptr,
4385                                            (unsigned long)(di + 1), name_len);
4386
4387                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
4388                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
4389
4390
4391                         /* is this a reference to our own snapshot? If so
4392                          * skip it.
4393                          *
4394                          * In contrast to old kernels, we insert the snapshot's
4395                          * dir item and dir index after it has been created, so
4396                          * we won't find a reference to our own snapshot. We
4397                          * still keep the following code for backward
4398                          * compatibility.
4399                          */
4400                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
4401                             location.objectid == root->root_key.objectid) {
4402                                 over = 0;
4403                                 goto skip;
4404                         }
4405                         over = filldir(dirent, name_ptr, name_len,
4406                                        found_key.offset, location.objectid,
4407                                        d_type);
4408
4409 skip:
4410                         if (name_ptr != tmp_name)
4411                                 kfree(name_ptr);
4412
4413                         if (over)
4414                                 goto nopos;
4415                         di_len = btrfs_dir_name_len(leaf, di) +
4416                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
4417                         di_cur += di_len;
4418                         di = (struct btrfs_dir_item *)((char *)di + di_len);
4419                 }
4420 next:
4421                 path->slots[0]++;
4422         }
4423
4424         if (key_type == BTRFS_DIR_INDEX_KEY) {
4425                 if (is_curr)
4426                         filp->f_pos++;
4427                 ret = btrfs_readdir_delayed_dir_index(filp, dirent, filldir,
4428                                                       &ins_list);
4429                 if (ret)
4430                         goto nopos;
4431         }
4432
4433         /* Reached end of directory/root. Bump pos past the last item. */
4434         if (key_type == BTRFS_DIR_INDEX_KEY)
4435                 /*
4436                  * 32-bit glibc will use getdents64, but then strtol -
4437                  * so the last number we can serve is this.
4438                  */
4439                 filp->f_pos = 0x7fffffff;
4440         else
4441                 filp->f_pos++;
4442 nopos:
4443         ret = 0;
4444 err:
4445         if (key_type == BTRFS_DIR_INDEX_KEY)
4446                 btrfs_put_delayed_items(&ins_list, &del_list);
4447         btrfs_free_path(path);
4448         return ret;
4449 }
4450
4451 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
4452 {
4453         struct btrfs_root *root = BTRFS_I(inode)->root;
4454         struct btrfs_trans_handle *trans;
4455         int ret = 0;
4456         bool nolock = false;
4457
4458         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
4459                 return 0;
4460
4461         if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(inode))
4462                 nolock = true;
4463
4464         if (wbc->sync_mode == WB_SYNC_ALL) {
4465                 if (nolock)
4466                         trans = btrfs_join_transaction_nolock(root);
4467                 else
4468                         trans = btrfs_join_transaction(root);
4469                 if (IS_ERR(trans))
4470                         return PTR_ERR(trans);
4471                 if (nolock)
4472                         ret = btrfs_end_transaction_nolock(trans, root);
4473                 else
4474                         ret = btrfs_commit_transaction(trans, root);
4475         }
4476         return ret;
4477 }
4478
4479 /*
4480  * This is somewhat expensive, updating the tree every time the
4481  * inode changes.  But, it is most likely to find the inode in cache.
4482  * FIXME, needs more benchmarking...there are no reasons other than performance
4483  * to keep or drop this code.
4484  */
4485 int btrfs_dirty_inode(struct inode *inode)
4486 {
4487         struct btrfs_root *root = BTRFS_I(inode)->root;
4488         struct btrfs_trans_handle *trans;
4489         int ret;
4490
4491         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
4492                 return 0;
4493
4494         trans = btrfs_join_transaction(root);
4495         if (IS_ERR(trans))
4496                 return PTR_ERR(trans);
4497
4498         ret = btrfs_update_inode(trans, root, inode);
4499         if (ret && ret == -ENOSPC) {
4500                 /* whoops, lets try again with the full transaction */
4501                 btrfs_end_transaction(trans, root);
4502                 trans = btrfs_start_transaction(root, 1);
4503                 if (IS_ERR(trans))
4504                         return PTR_ERR(trans);
4505
4506                 ret = btrfs_update_inode(trans, root, inode);
4507         }
4508         btrfs_end_transaction(trans, root);
4509         if (BTRFS_I(inode)->delayed_node)
4510                 btrfs_balance_delayed_items(root);
4511
4512         return ret;
4513 }
4514
4515 /*
4516  * This is a copy of file_update_time.  We need this so we can return error on
4517  * ENOSPC for updating the inode in the case of file write and mmap writes.
4518  */
4519 static int btrfs_update_time(struct inode *inode, struct timespec *now,
4520                              int flags)
4521 {
4522         struct btrfs_root *root = BTRFS_I(inode)->root;
4523
4524         if (btrfs_root_readonly(root))
4525                 return -EROFS;
4526
4527         if (flags & S_VERSION)
4528                 inode_inc_iversion(inode);
4529         if (flags & S_CTIME)
4530                 inode->i_ctime = *now;
4531         if (flags & S_MTIME)
4532                 inode->i_mtime = *now;
4533         if (flags & S_ATIME)
4534                 inode->i_atime = *now;
4535         return btrfs_dirty_inode(inode);
4536 }
4537
4538 /*
4539  * find the highest existing sequence number in a directory
4540  * and then set the in-memory index_cnt variable to reflect
4541  * free sequence numbers
4542  */
4543 static int btrfs_set_inode_index_count(struct inode *inode)
4544 {
4545         struct btrfs_root *root = BTRFS_I(inode)->root;
4546         struct btrfs_key key, found_key;
4547         struct btrfs_path *path;
4548         struct extent_buffer *leaf;
4549         int ret;
4550
4551         key.objectid = btrfs_ino(inode);
4552         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
4553         key.offset = (u64)-1;
4554
4555         path = btrfs_alloc_path();
4556         if (!path)
4557                 return -ENOMEM;
4558
4559         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4560         if (ret < 0)
4561                 goto out;
4562         /* FIXME: we should be able to handle this */
4563         if (ret == 0)
4564                 goto out;
4565         ret = 0;
4566
4567         /*
4568          * MAGIC NUMBER EXPLANATION:
4569          * since we search a directory based on f_pos we have to start at 2
4570          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
4571          * else has to start at 2
4572          */
4573         if (path->slots[0] == 0) {
4574                 BTRFS_I(inode)->index_cnt = 2;
4575                 goto out;
4576         }
4577
4578         path->slots[0]--;
4579
4580         leaf = path->nodes[0];
4581         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4582
4583         if (found_key.objectid != btrfs_ino(inode) ||
4584             btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
4585                 BTRFS_I(inode)->index_cnt = 2;
4586                 goto out;
4587         }
4588
4589         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
4590 out:
4591         btrfs_free_path(path);
4592         return ret;
4593 }
4594
4595 /*
4596  * helper to find a free sequence number in a given directory.  This current
4597  * code is very simple, later versions will do smarter things in the btree
4598  */
4599 int btrfs_set_inode_index(struct inode *dir, u64 *index)
4600 {
4601         int ret = 0;
4602
4603         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
4604                 ret = btrfs_inode_delayed_dir_index_count(dir);
4605                 if (ret) {
4606                         ret = btrfs_set_inode_index_count(dir);
4607                         if (ret)
4608                                 return ret;
4609                 }
4610         }
4611
4612         *index = BTRFS_I(dir)->index_cnt;
4613         BTRFS_I(dir)->index_cnt++;
4614
4615         return ret;
4616 }
4617
4618 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
4619                                      struct btrfs_root *root,
4620                                      struct inode *dir,
4621                                      const char *name, int name_len,
4622                                      u64 ref_objectid, u64 objectid,
4623                                      umode_t mode, u64 *index)
4624 {
4625         struct inode *inode;
4626         struct btrfs_inode_item *inode_item;
4627         struct btrfs_key *location;
4628         struct btrfs_path *path;
4629         struct btrfs_inode_ref *ref;
4630         struct btrfs_key key[2];
4631         u32 sizes[2];
4632         unsigned long ptr;
4633         int ret;
4634         int owner;
4635
4636         path = btrfs_alloc_path();
4637         if (!path)
4638                 return ERR_PTR(-ENOMEM);
4639
4640         inode = new_inode(root->fs_info->sb);
4641         if (!inode) {
4642                 btrfs_free_path(path);
4643                 return ERR_PTR(-ENOMEM);
4644         }
4645
4646         /*
4647          * we have to initialize this early, so we can reclaim the inode
4648          * number if we fail afterwards in this function.
4649          */
4650         inode->i_ino = objectid;
4651
4652         if (dir) {
4653                 trace_btrfs_inode_request(dir);
4654
4655                 ret = btrfs_set_inode_index(dir, index);
4656                 if (ret) {
4657                         btrfs_free_path(path);
4658                         iput(inode);
4659                         return ERR_PTR(ret);
4660                 }
4661         }
4662         /*
4663          * index_cnt is ignored for everything but a dir,
4664          * btrfs_get_inode_index_count has an explanation for the magic
4665          * number
4666          */
4667         BTRFS_I(inode)->index_cnt = 2;
4668         BTRFS_I(inode)->root = root;
4669         BTRFS_I(inode)->generation = trans->transid;
4670         inode->i_generation = BTRFS_I(inode)->generation;
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         memset_extent_buffer(path->nodes[0], 0, (unsigned long)inode_item,
4699                              sizeof(*inode_item));
4700         fill_inode_item(trans, path->nodes[0], inode_item, inode);
4701
4702         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
4703                              struct btrfs_inode_ref);
4704         btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
4705         btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
4706         ptr = (unsigned long)(ref + 1);
4707         write_extent_buffer(path->nodes[0], name, ptr, name_len);
4708
4709         btrfs_mark_buffer_dirty(path->nodes[0]);
4710         btrfs_free_path(path);
4711
4712         location = &BTRFS_I(inode)->location;
4713         location->objectid = objectid;
4714         location->offset = 0;
4715         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
4716
4717         btrfs_inherit_iflags(inode, dir);
4718
4719         if (S_ISREG(mode)) {
4720                 if (btrfs_test_opt(root, NODATASUM))
4721                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
4722                 if (btrfs_test_opt(root, NODATACOW) ||
4723                     (BTRFS_I(dir)->flags & BTRFS_INODE_NODATACOW))
4724                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
4725         }
4726
4727         insert_inode_hash(inode);
4728         inode_tree_add(inode);
4729
4730         trace_btrfs_inode_new(inode);
4731         btrfs_set_inode_last_trans(trans, inode);
4732
4733         btrfs_update_root_times(trans, root);
4734
4735         return inode;
4736 fail:
4737         if (dir)
4738                 BTRFS_I(dir)->index_cnt--;
4739         btrfs_free_path(path);
4740         iput(inode);
4741         return ERR_PTR(ret);
4742 }
4743
4744 static inline u8 btrfs_inode_type(struct inode *inode)
4745 {
4746         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
4747 }
4748
4749 /*
4750  * utility function to add 'inode' into 'parent_inode' with
4751  * a give name and a given sequence number.
4752  * if 'add_backref' is true, also insert a backref from the
4753  * inode to the parent directory.
4754  */
4755 int btrfs_add_link(struct btrfs_trans_handle *trans,
4756                    struct inode *parent_inode, struct inode *inode,
4757                    const char *name, int name_len, int add_backref, u64 index)
4758 {
4759         int ret = 0;
4760         struct btrfs_key key;
4761         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
4762         u64 ino = btrfs_ino(inode);
4763         u64 parent_ino = btrfs_ino(parent_inode);
4764
4765         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
4766                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
4767         } else {
4768                 key.objectid = ino;
4769                 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
4770                 key.offset = 0;
4771         }
4772
4773         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
4774                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
4775                                          key.objectid, root->root_key.objectid,
4776                                          parent_ino, index, name, name_len);
4777         } else if (add_backref) {
4778                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
4779                                              parent_ino, index);
4780         }
4781
4782         /* Nothing to clean up yet */
4783         if (ret)
4784                 return ret;
4785
4786         ret = btrfs_insert_dir_item(trans, root, name, name_len,
4787                                     parent_inode, &key,
4788                                     btrfs_inode_type(inode), index);
4789         if (ret == -EEXIST)
4790                 goto fail_dir_item;
4791         else if (ret) {
4792                 btrfs_abort_transaction(trans, root, ret);
4793                 return ret;
4794         }
4795
4796         btrfs_i_size_write(parent_inode, parent_inode->i_size +
4797                            name_len * 2);
4798         inode_inc_iversion(parent_inode);
4799         parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
4800         ret = btrfs_update_inode(trans, root, parent_inode);
4801         if (ret)
4802                 btrfs_abort_transaction(trans, root, ret);
4803         return ret;
4804
4805 fail_dir_item:
4806         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
4807                 u64 local_index;
4808                 int err;
4809                 err = btrfs_del_root_ref(trans, root->fs_info->tree_root,
4810                                  key.objectid, root->root_key.objectid,
4811                                  parent_ino, &local_index, name, name_len);
4812
4813         } else if (add_backref) {
4814                 u64 local_index;
4815                 int err;
4816
4817                 err = btrfs_del_inode_ref(trans, root, name, name_len,
4818                                           ino, parent_ino, &local_index);
4819         }
4820         return ret;
4821 }
4822
4823 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
4824                             struct inode *dir, struct dentry *dentry,
4825                             struct inode *inode, int backref, u64 index)
4826 {
4827         int err = btrfs_add_link(trans, dir, inode,
4828                                  dentry->d_name.name, dentry->d_name.len,
4829                                  backref, index);
4830         if (err > 0)
4831                 err = -EEXIST;
4832         return err;
4833 }
4834
4835 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
4836                         umode_t mode, dev_t rdev)
4837 {
4838         struct btrfs_trans_handle *trans;
4839         struct btrfs_root *root = BTRFS_I(dir)->root;
4840         struct inode *inode = NULL;
4841         int err;
4842         int drop_inode = 0;
4843         u64 objectid;
4844         unsigned long nr = 0;
4845         u64 index = 0;
4846
4847         if (!new_valid_dev(rdev))
4848                 return -EINVAL;
4849
4850         /*
4851          * 2 for inode item and ref
4852          * 2 for dir items
4853          * 1 for xattr if selinux is on
4854          */
4855         trans = btrfs_start_transaction(root, 5);
4856         if (IS_ERR(trans))
4857                 return PTR_ERR(trans);
4858
4859         err = btrfs_find_free_ino(root, &objectid);
4860         if (err)
4861                 goto out_unlock;
4862
4863         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4864                                 dentry->d_name.len, btrfs_ino(dir), objectid,
4865                                 mode, &index);
4866         if (IS_ERR(inode)) {
4867                 err = PTR_ERR(inode);
4868                 goto out_unlock;
4869         }
4870
4871         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4872         if (err) {
4873                 drop_inode = 1;
4874                 goto out_unlock;
4875         }
4876
4877         /*
4878         * If the active LSM wants to access the inode during
4879         * d_instantiate it needs these. Smack checks to see
4880         * if the filesystem supports xattrs by looking at the
4881         * ops vector.
4882         */
4883
4884         inode->i_op = &btrfs_special_inode_operations;
4885         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
4886         if (err)
4887                 drop_inode = 1;
4888         else {
4889                 init_special_inode(inode, inode->i_mode, rdev);
4890                 btrfs_update_inode(trans, root, inode);
4891                 d_instantiate(dentry, inode);
4892         }
4893 out_unlock:
4894         nr = trans->blocks_used;
4895         btrfs_end_transaction(trans, root);
4896         btrfs_btree_balance_dirty(root, nr);
4897         if (drop_inode) {
4898                 inode_dec_link_count(inode);
4899                 iput(inode);
4900         }
4901         return err;
4902 }
4903
4904 static int btrfs_create(struct inode *dir, struct dentry *dentry,
4905                         umode_t mode, struct nameidata *nd)
4906 {
4907         struct btrfs_trans_handle *trans;
4908         struct btrfs_root *root = BTRFS_I(dir)->root;
4909         struct inode *inode = NULL;
4910         int drop_inode = 0;
4911         int err;
4912         unsigned long nr = 0;
4913         u64 objectid;
4914         u64 index = 0;
4915
4916         /*
4917          * 2 for inode item and ref
4918          * 2 for dir items
4919          * 1 for xattr if selinux is on
4920          */
4921         trans = btrfs_start_transaction(root, 5);
4922         if (IS_ERR(trans))
4923                 return PTR_ERR(trans);
4924
4925         err = btrfs_find_free_ino(root, &objectid);
4926         if (err)
4927                 goto out_unlock;
4928
4929         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4930                                 dentry->d_name.len, btrfs_ino(dir), objectid,
4931                                 mode, &index);
4932         if (IS_ERR(inode)) {
4933                 err = PTR_ERR(inode);
4934                 goto out_unlock;
4935         }
4936
4937         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4938         if (err) {
4939                 drop_inode = 1;
4940                 goto out_unlock;
4941         }
4942
4943         /*
4944         * If the active LSM wants to access the inode during
4945         * d_instantiate it needs these. Smack checks to see
4946         * if the filesystem supports xattrs by looking at the
4947         * ops vector.
4948         */
4949         inode->i_fop = &btrfs_file_operations;
4950         inode->i_op = &btrfs_file_inode_operations;
4951
4952         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
4953         if (err)
4954                 drop_inode = 1;
4955         else {
4956                 inode->i_mapping->a_ops = &btrfs_aops;
4957                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
4958                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
4959                 d_instantiate(dentry, inode);
4960         }
4961 out_unlock:
4962         nr = trans->blocks_used;
4963         btrfs_end_transaction(trans, root);
4964         if (drop_inode) {
4965                 inode_dec_link_count(inode);
4966                 iput(inode);
4967         }
4968         btrfs_btree_balance_dirty(root, nr);
4969         return err;
4970 }
4971
4972 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
4973                       struct dentry *dentry)
4974 {
4975         struct btrfs_trans_handle *trans;
4976         struct btrfs_root *root = BTRFS_I(dir)->root;
4977         struct inode *inode = old_dentry->d_inode;
4978         u64 index;
4979         unsigned long nr = 0;
4980         int err;
4981         int drop_inode = 0;
4982
4983         /* do not allow sys_link's with other subvols of the same device */
4984         if (root->objectid != BTRFS_I(inode)->root->objectid)
4985                 return -EXDEV;
4986
4987         if (inode->i_nlink == ~0U)
4988                 return -EMLINK;
4989
4990         err = btrfs_set_inode_index(dir, &index);
4991         if (err)
4992                 goto fail;
4993
4994         /*
4995          * 2 items for inode and inode ref
4996          * 2 items for dir items
4997          * 1 item for parent inode
4998          */
4999         trans = btrfs_start_transaction(root, 5);
5000         if (IS_ERR(trans)) {
5001                 err = PTR_ERR(trans);
5002                 goto fail;
5003         }
5004
5005         btrfs_inc_nlink(inode);
5006         inode_inc_iversion(inode);
5007         inode->i_ctime = CURRENT_TIME;
5008         ihold(inode);
5009
5010         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
5011
5012         if (err) {
5013                 drop_inode = 1;
5014         } else {
5015                 struct dentry *parent = dentry->d_parent;
5016                 err = btrfs_update_inode(trans, root, inode);
5017                 if (err)
5018                         goto fail;
5019                 d_instantiate(dentry, inode);
5020                 btrfs_log_new_name(trans, inode, NULL, parent);
5021         }
5022
5023         nr = trans->blocks_used;
5024         btrfs_end_transaction(trans, root);
5025 fail:
5026         if (drop_inode) {
5027                 inode_dec_link_count(inode);
5028                 iput(inode);
5029         }
5030         btrfs_btree_balance_dirty(root, nr);
5031         return err;
5032 }
5033
5034 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
5035 {
5036         struct inode *inode = NULL;
5037         struct btrfs_trans_handle *trans;
5038         struct btrfs_root *root = BTRFS_I(dir)->root;
5039         int err = 0;
5040         int drop_on_err = 0;
5041         u64 objectid = 0;
5042         u64 index = 0;
5043         unsigned long nr = 1;
5044
5045         /*
5046          * 2 items for inode and ref
5047          * 2 items for dir items
5048          * 1 for xattr if selinux is on
5049          */
5050         trans = btrfs_start_transaction(root, 5);
5051         if (IS_ERR(trans))
5052                 return PTR_ERR(trans);
5053
5054         err = btrfs_find_free_ino(root, &objectid);
5055         if (err)
5056                 goto out_fail;
5057
5058         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5059                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5060                                 S_IFDIR | mode, &index);
5061         if (IS_ERR(inode)) {
5062                 err = PTR_ERR(inode);
5063                 goto out_fail;
5064         }
5065
5066         drop_on_err = 1;
5067
5068         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5069         if (err)
5070                 goto out_fail;
5071
5072         inode->i_op = &btrfs_dir_inode_operations;
5073         inode->i_fop = &btrfs_dir_file_operations;
5074
5075         btrfs_i_size_write(inode, 0);
5076         err = btrfs_update_inode(trans, root, inode);
5077         if (err)
5078                 goto out_fail;
5079
5080         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
5081                              dentry->d_name.len, 0, index);
5082         if (err)
5083                 goto out_fail;
5084
5085         d_instantiate(dentry, inode);
5086         drop_on_err = 0;
5087
5088 out_fail:
5089         nr = trans->blocks_used;
5090         btrfs_end_transaction(trans, root);
5091         if (drop_on_err)
5092                 iput(inode);
5093         btrfs_btree_balance_dirty(root, nr);
5094         return err;
5095 }
5096
5097 /* helper for btfs_get_extent.  Given an existing extent in the tree,
5098  * and an extent that you want to insert, deal with overlap and insert
5099  * the new extent into the tree.
5100  */
5101 static int merge_extent_mapping(struct extent_map_tree *em_tree,
5102                                 struct extent_map *existing,
5103                                 struct extent_map *em,
5104                                 u64 map_start, u64 map_len)
5105 {
5106         u64 start_diff;
5107
5108         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
5109         start_diff = map_start - em->start;
5110         em->start = map_start;
5111         em->len = map_len;
5112         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
5113             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
5114                 em->block_start += start_diff;
5115                 em->block_len -= start_diff;
5116         }
5117         return add_extent_mapping(em_tree, em);
5118 }
5119
5120 static noinline int uncompress_inline(struct btrfs_path *path,
5121                                       struct inode *inode, struct page *page,
5122                                       size_t pg_offset, u64 extent_offset,
5123                                       struct btrfs_file_extent_item *item)
5124 {
5125         int ret;
5126         struct extent_buffer *leaf = path->nodes[0];
5127         char *tmp;
5128         size_t max_size;
5129         unsigned long inline_size;
5130         unsigned long ptr;
5131         int compress_type;
5132
5133         WARN_ON(pg_offset != 0);
5134         compress_type = btrfs_file_extent_compression(leaf, item);
5135         max_size = btrfs_file_extent_ram_bytes(leaf, item);
5136         inline_size = btrfs_file_extent_inline_item_len(leaf,
5137                                         btrfs_item_nr(leaf, path->slots[0]));
5138         tmp = kmalloc(inline_size, GFP_NOFS);
5139         if (!tmp)
5140                 return -ENOMEM;
5141         ptr = btrfs_file_extent_inline_start(item);
5142
5143         read_extent_buffer(leaf, tmp, ptr, inline_size);
5144
5145         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
5146         ret = btrfs_decompress(compress_type, tmp, page,
5147                                extent_offset, inline_size, max_size);
5148         if (ret) {
5149                 char *kaddr = kmap_atomic(page);
5150                 unsigned long copy_size = min_t(u64,
5151                                   PAGE_CACHE_SIZE - pg_offset,
5152                                   max_size - extent_offset);
5153                 memset(kaddr + pg_offset, 0, copy_size);
5154                 kunmap_atomic(kaddr);
5155         }
5156         kfree(tmp);
5157         return 0;
5158 }
5159
5160 /*
5161  * a bit scary, this does extent mapping from logical file offset to the disk.
5162  * the ugly parts come from merging extents from the disk with the in-ram
5163  * representation.  This gets more complex because of the data=ordered code,
5164  * where the in-ram extents might be locked pending data=ordered completion.
5165  *
5166  * This also copies inline extents directly into the page.
5167  */
5168
5169 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
5170                                     size_t pg_offset, u64 start, u64 len,
5171                                     int create)
5172 {
5173         int ret;
5174         int err = 0;
5175         u64 bytenr;
5176         u64 extent_start = 0;
5177         u64 extent_end = 0;
5178         u64 objectid = btrfs_ino(inode);
5179         u32 found_type;
5180         struct btrfs_path *path = NULL;
5181         struct btrfs_root *root = BTRFS_I(inode)->root;
5182         struct btrfs_file_extent_item *item;
5183         struct extent_buffer *leaf;
5184         struct btrfs_key found_key;
5185         struct extent_map *em = NULL;
5186         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
5187         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
5188         struct btrfs_trans_handle *trans = NULL;
5189         int compress_type;
5190
5191 again:
5192         read_lock(&em_tree->lock);
5193         em = lookup_extent_mapping(em_tree, start, len);
5194         if (em)
5195                 em->bdev = root->fs_info->fs_devices->latest_bdev;
5196         read_unlock(&em_tree->lock);
5197
5198         if (em) {
5199                 if (em->start > start || em->start + em->len <= start)
5200                         free_extent_map(em);
5201                 else if (em->block_start == EXTENT_MAP_INLINE && page)
5202                         free_extent_map(em);
5203                 else
5204                         goto out;
5205         }
5206         em = alloc_extent_map();
5207         if (!em) {
5208                 err = -ENOMEM;
5209                 goto out;
5210         }
5211         em->bdev = root->fs_info->fs_devices->latest_bdev;
5212         em->start = EXTENT_MAP_HOLE;
5213         em->orig_start = EXTENT_MAP_HOLE;
5214         em->len = (u64)-1;
5215         em->block_len = (u64)-1;
5216
5217         if (!path) {
5218                 path = btrfs_alloc_path();
5219                 if (!path) {
5220                         err = -ENOMEM;
5221                         goto out;
5222                 }
5223                 /*
5224                  * Chances are we'll be called again, so go ahead and do
5225                  * readahead
5226                  */
5227                 path->reada = 1;
5228         }
5229
5230         ret = btrfs_lookup_file_extent(trans, root, path,
5231                                        objectid, start, trans != NULL);
5232         if (ret < 0) {
5233                 err = ret;
5234                 goto out;
5235         }
5236
5237         if (ret != 0) {
5238                 if (path->slots[0] == 0)
5239                         goto not_found;
5240                 path->slots[0]--;
5241         }
5242
5243         leaf = path->nodes[0];
5244         item = btrfs_item_ptr(leaf, path->slots[0],
5245                               struct btrfs_file_extent_item);
5246         /* are we inside the extent that was found? */
5247         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5248         found_type = btrfs_key_type(&found_key);
5249         if (found_key.objectid != objectid ||
5250             found_type != BTRFS_EXTENT_DATA_KEY) {
5251                 goto not_found;
5252         }
5253
5254         found_type = btrfs_file_extent_type(leaf, item);
5255         extent_start = found_key.offset;
5256         compress_type = btrfs_file_extent_compression(leaf, item);
5257         if (found_type == BTRFS_FILE_EXTENT_REG ||
5258             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
5259                 extent_end = extent_start +
5260                        btrfs_file_extent_num_bytes(leaf, item);
5261         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
5262                 size_t size;
5263                 size = btrfs_file_extent_inline_len(leaf, item);
5264                 extent_end = (extent_start + size + root->sectorsize - 1) &
5265                         ~((u64)root->sectorsize - 1);
5266         }
5267
5268         if (start >= extent_end) {
5269                 path->slots[0]++;
5270                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
5271                         ret = btrfs_next_leaf(root, path);
5272                         if (ret < 0) {
5273                                 err = ret;
5274                                 goto out;
5275                         }
5276                         if (ret > 0)
5277                                 goto not_found;
5278                         leaf = path->nodes[0];
5279                 }
5280                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5281                 if (found_key.objectid != objectid ||
5282                     found_key.type != BTRFS_EXTENT_DATA_KEY)
5283                         goto not_found;
5284                 if (start + len <= found_key.offset)
5285                         goto not_found;
5286                 em->start = start;
5287                 em->len = found_key.offset - start;
5288                 goto not_found_em;
5289         }
5290
5291         if (found_type == BTRFS_FILE_EXTENT_REG ||
5292             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
5293                 em->start = extent_start;
5294                 em->len = extent_end - extent_start;
5295                 em->orig_start = extent_start -
5296                                  btrfs_file_extent_offset(leaf, item);
5297                 bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
5298                 if (bytenr == 0) {
5299                         em->block_start = EXTENT_MAP_HOLE;
5300                         goto insert;
5301                 }
5302                 if (compress_type != BTRFS_COMPRESS_NONE) {
5303                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
5304                         em->compress_type = compress_type;
5305                         em->block_start = bytenr;
5306                         em->block_len = btrfs_file_extent_disk_num_bytes(leaf,
5307                                                                          item);
5308                 } else {
5309                         bytenr += btrfs_file_extent_offset(leaf, item);
5310                         em->block_start = bytenr;
5311                         em->block_len = em->len;
5312                         if (found_type == BTRFS_FILE_EXTENT_PREALLOC)
5313                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
5314                 }
5315                 goto insert;
5316         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
5317                 unsigned long ptr;
5318                 char *map;
5319                 size_t size;
5320                 size_t extent_offset;
5321                 size_t copy_size;
5322
5323                 em->block_start = EXTENT_MAP_INLINE;
5324                 if (!page || create) {
5325                         em->start = extent_start;
5326                         em->len = extent_end - extent_start;
5327                         goto out;
5328                 }
5329
5330                 size = btrfs_file_extent_inline_len(leaf, item);
5331                 extent_offset = page_offset(page) + pg_offset - extent_start;
5332                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
5333                                 size - extent_offset);
5334                 em->start = extent_start + extent_offset;
5335                 em->len = (copy_size + root->sectorsize - 1) &
5336                         ~((u64)root->sectorsize - 1);
5337                 em->orig_start = EXTENT_MAP_INLINE;
5338                 if (compress_type) {
5339                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
5340                         em->compress_type = compress_type;
5341                 }
5342                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
5343                 if (create == 0 && !PageUptodate(page)) {
5344                         if (btrfs_file_extent_compression(leaf, item) !=
5345                             BTRFS_COMPRESS_NONE) {
5346                                 ret = uncompress_inline(path, inode, page,
5347                                                         pg_offset,
5348                                                         extent_offset, item);
5349                                 BUG_ON(ret); /* -ENOMEM */
5350                         } else {
5351                                 map = kmap(page);
5352                                 read_extent_buffer(leaf, map + pg_offset, ptr,
5353                                                    copy_size);
5354                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
5355                                         memset(map + pg_offset + copy_size, 0,
5356                                                PAGE_CACHE_SIZE - pg_offset -
5357                                                copy_size);
5358                                 }
5359                                 kunmap(page);
5360                         }
5361                         flush_dcache_page(page);
5362                 } else if (create && PageUptodate(page)) {
5363                         BUG();
5364                         if (!trans) {
5365                                 kunmap(page);
5366                                 free_extent_map(em);
5367                                 em = NULL;
5368
5369                                 btrfs_release_path(path);
5370                                 trans = btrfs_join_transaction(root);
5371
5372                                 if (IS_ERR(trans))
5373                                         return ERR_CAST(trans);
5374                                 goto again;
5375                         }
5376                         map = kmap(page);
5377                         write_extent_buffer(leaf, map + pg_offset, ptr,
5378                                             copy_size);
5379                         kunmap(page);
5380                         btrfs_mark_buffer_dirty(leaf);
5381                 }
5382                 set_extent_uptodate(io_tree, em->start,
5383                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
5384                 goto insert;
5385         } else {
5386                 printk(KERN_ERR "btrfs unknown found_type %d\n", found_type);
5387                 WARN_ON(1);
5388         }
5389 not_found:
5390         em->start = start;
5391         em->len = len;
5392 not_found_em:
5393         em->block_start = EXTENT_MAP_HOLE;
5394         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
5395 insert:
5396         btrfs_release_path(path);
5397         if (em->start > start || extent_map_end(em) <= start) {
5398                 printk(KERN_ERR "Btrfs: bad extent! em: [%llu %llu] passed "
5399                        "[%llu %llu]\n", (unsigned long long)em->start,
5400                        (unsigned long long)em->len,
5401                        (unsigned long long)start,
5402                        (unsigned long long)len);
5403                 err = -EIO;
5404                 goto out;
5405         }
5406
5407         err = 0;
5408         write_lock(&em_tree->lock);
5409         ret = add_extent_mapping(em_tree, em);
5410         /* it is possible that someone inserted the extent into the tree
5411          * while we had the lock dropped.  It is also possible that
5412          * an overlapping map exists in the tree
5413          */
5414         if (ret == -EEXIST) {
5415                 struct extent_map *existing;
5416
5417                 ret = 0;
5418
5419                 existing = lookup_extent_mapping(em_tree, start, len);
5420                 if (existing && (existing->start > start ||
5421                     existing->start + existing->len <= start)) {
5422                         free_extent_map(existing);
5423                         existing = NULL;
5424                 }
5425                 if (!existing) {
5426                         existing = lookup_extent_mapping(em_tree, em->start,
5427                                                          em->len);
5428                         if (existing) {
5429                                 err = merge_extent_mapping(em_tree, existing,
5430                                                            em, start,
5431                                                            root->sectorsize);
5432                                 free_extent_map(existing);
5433                                 if (err) {
5434                                         free_extent_map(em);
5435                                         em = NULL;
5436                                 }
5437                         } else {
5438                                 err = -EIO;
5439                                 free_extent_map(em);
5440                                 em = NULL;
5441                         }
5442                 } else {
5443                         free_extent_map(em);
5444                         em = existing;
5445                         err = 0;
5446                 }
5447         }
5448         write_unlock(&em_tree->lock);
5449 out:
5450
5451         trace_btrfs_get_extent(root, em);
5452
5453         if (path)
5454                 btrfs_free_path(path);
5455         if (trans) {
5456                 ret = btrfs_end_transaction(trans, root);
5457                 if (!err)
5458                         err = ret;
5459         }
5460         if (err) {
5461                 free_extent_map(em);
5462                 return ERR_PTR(err);
5463         }
5464         BUG_ON(!em); /* Error is always set */
5465         return em;
5466 }
5467
5468 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
5469                                            size_t pg_offset, u64 start, u64 len,
5470                                            int create)
5471 {
5472         struct extent_map *em;
5473         struct extent_map *hole_em = NULL;
5474         u64 range_start = start;
5475         u64 end;
5476         u64 found;
5477         u64 found_end;
5478         int err = 0;
5479
5480         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
5481         if (IS_ERR(em))
5482                 return em;
5483         if (em) {
5484                 /*
5485                  * if our em maps to a hole, there might
5486                  * actually be delalloc bytes behind it
5487                  */
5488                 if (em->block_start != EXTENT_MAP_HOLE)
5489                         return em;
5490                 else
5491                         hole_em = em;
5492         }
5493
5494         /* check to see if we've wrapped (len == -1 or similar) */
5495         end = start + len;
5496         if (end < start)
5497                 end = (u64)-1;
5498         else
5499                 end -= 1;
5500
5501         em = NULL;
5502
5503         /* ok, we didn't find anything, lets look for delalloc */
5504         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
5505                                  end, len, EXTENT_DELALLOC, 1);
5506         found_end = range_start + found;
5507         if (found_end < range_start)
5508                 found_end = (u64)-1;
5509
5510         /*
5511          * we didn't find anything useful, return
5512          * the original results from get_extent()
5513          */
5514         if (range_start > end || found_end <= start) {
5515                 em = hole_em;
5516                 hole_em = NULL;
5517                 goto out;
5518         }
5519
5520         /* adjust the range_start to make sure it doesn't
5521          * go backwards from the start they passed in
5522          */
5523         range_start = max(start,range_start);
5524         found = found_end - range_start;
5525
5526         if (found > 0) {
5527                 u64 hole_start = start;
5528                 u64 hole_len = len;
5529
5530                 em = alloc_extent_map();
5531                 if (!em) {
5532                         err = -ENOMEM;
5533                         goto out;
5534                 }
5535                 /*
5536                  * when btrfs_get_extent can't find anything it
5537                  * returns one huge hole
5538                  *
5539                  * make sure what it found really fits our range, and
5540                  * adjust to make sure it is based on the start from
5541                  * the caller
5542                  */
5543                 if (hole_em) {
5544                         u64 calc_end = extent_map_end(hole_em);
5545
5546                         if (calc_end <= start || (hole_em->start > end)) {
5547                                 free_extent_map(hole_em);
5548                                 hole_em = NULL;
5549                         } else {
5550                                 hole_start = max(hole_em->start, start);
5551                                 hole_len = calc_end - hole_start;
5552                         }
5553                 }
5554                 em->bdev = NULL;
5555                 if (hole_em && range_start > hole_start) {
5556                         /* our hole starts before our delalloc, so we
5557                          * have to return just the parts of the hole
5558                          * that go until  the delalloc starts
5559                          */
5560                         em->len = min(hole_len,
5561                                       range_start - hole_start);
5562                         em->start = hole_start;
5563                         em->orig_start = hole_start;
5564                         /*
5565                          * don't adjust block start at all,
5566                          * it is fixed at EXTENT_MAP_HOLE
5567                          */
5568                         em->block_start = hole_em->block_start;
5569                         em->block_len = hole_len;
5570                 } else {
5571                         em->start = range_start;
5572                         em->len = found;
5573                         em->orig_start = range_start;
5574                         em->block_start = EXTENT_MAP_DELALLOC;
5575                         em->block_len = found;
5576                 }
5577         } else if (hole_em) {
5578                 return hole_em;
5579         }
5580 out:
5581
5582         free_extent_map(hole_em);
5583         if (err) {
5584                 free_extent_map(em);
5585                 return ERR_PTR(err);
5586         }
5587         return em;
5588 }
5589
5590 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
5591                                                   struct extent_map *em,
5592