vfs: push dentry_unhash on rename_dir into file systems
[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 "compat.h"
41 #include "ctree.h"
42 #include "disk-io.h"
43 #include "transaction.h"
44 #include "btrfs_inode.h"
45 #include "ioctl.h"
46 #include "print-tree.h"
47 #include "volumes.h"
48 #include "ordered-data.h"
49 #include "xattr.h"
50 #include "tree-log.h"
51 #include "compression.h"
52 #include "locking.h"
53 #include "free-space-cache.h"
54
55 struct btrfs_iget_args {
56         u64 ino;
57         struct btrfs_root *root;
58 };
59
60 static const struct inode_operations btrfs_dir_inode_operations;
61 static const struct inode_operations btrfs_symlink_inode_operations;
62 static const struct inode_operations btrfs_dir_ro_inode_operations;
63 static const struct inode_operations btrfs_special_inode_operations;
64 static const struct inode_operations btrfs_file_inode_operations;
65 static const struct address_space_operations btrfs_aops;
66 static const struct address_space_operations btrfs_symlink_aops;
67 static const struct file_operations btrfs_dir_file_operations;
68 static struct extent_io_ops btrfs_extent_io_ops;
69
70 static struct kmem_cache *btrfs_inode_cachep;
71 struct kmem_cache *btrfs_trans_handle_cachep;
72 struct kmem_cache *btrfs_transaction_cachep;
73 struct kmem_cache *btrfs_path_cachep;
74 struct kmem_cache *btrfs_free_space_cachep;
75
76 #define S_SHIFT 12
77 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
78         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
79         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
80         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
81         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
82         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
83         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
84         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
85 };
86
87 static int btrfs_setsize(struct inode *inode, loff_t newsize);
88 static int btrfs_truncate(struct inode *inode);
89 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end);
90 static noinline int cow_file_range(struct inode *inode,
91                                    struct page *locked_page,
92                                    u64 start, u64 end, int *page_started,
93                                    unsigned long *nr_written, int unlock);
94
95 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
96                                      struct inode *inode,  struct inode *dir,
97                                      const struct qstr *qstr)
98 {
99         int err;
100
101         err = btrfs_init_acl(trans, inode, dir);
102         if (!err)
103                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
104         return err;
105 }
106
107 /*
108  * this does all the hard work for inserting an inline extent into
109  * the btree.  The caller should have done a btrfs_drop_extents so that
110  * no overlapping inline items exist in the btree
111  */
112 static noinline int insert_inline_extent(struct btrfs_trans_handle *trans,
113                                 struct btrfs_root *root, struct inode *inode,
114                                 u64 start, size_t size, size_t compressed_size,
115                                 int compress_type,
116                                 struct page **compressed_pages)
117 {
118         struct btrfs_key key;
119         struct btrfs_path *path;
120         struct extent_buffer *leaf;
121         struct page *page = NULL;
122         char *kaddr;
123         unsigned long ptr;
124         struct btrfs_file_extent_item *ei;
125         int err = 0;
126         int ret;
127         size_t cur_size = size;
128         size_t datasize;
129         unsigned long offset;
130
131         if (compressed_size && compressed_pages)
132                 cur_size = compressed_size;
133
134         path = btrfs_alloc_path();
135         if (!path)
136                 return -ENOMEM;
137
138         path->leave_spinning = 1;
139         btrfs_set_trans_block_group(trans, inode);
140
141         key.objectid = inode->i_ino;
142         key.offset = start;
143         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
144         datasize = btrfs_file_extent_calc_inline_size(cur_size);
145
146         inode_add_bytes(inode, size);
147         ret = btrfs_insert_empty_item(trans, root, path, &key,
148                                       datasize);
149         BUG_ON(ret);
150         if (ret) {
151                 err = ret;
152                 goto fail;
153         }
154         leaf = path->nodes[0];
155         ei = btrfs_item_ptr(leaf, path->slots[0],
156                             struct btrfs_file_extent_item);
157         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
158         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
159         btrfs_set_file_extent_encryption(leaf, ei, 0);
160         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
161         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
162         ptr = btrfs_file_extent_inline_start(ei);
163
164         if (compress_type != BTRFS_COMPRESS_NONE) {
165                 struct page *cpage;
166                 int i = 0;
167                 while (compressed_size > 0) {
168                         cpage = compressed_pages[i];
169                         cur_size = min_t(unsigned long, compressed_size,
170                                        PAGE_CACHE_SIZE);
171
172                         kaddr = kmap_atomic(cpage, KM_USER0);
173                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
174                         kunmap_atomic(kaddr, KM_USER0);
175
176                         i++;
177                         ptr += cur_size;
178                         compressed_size -= cur_size;
179                 }
180                 btrfs_set_file_extent_compression(leaf, ei,
181                                                   compress_type);
182         } else {
183                 page = find_get_page(inode->i_mapping,
184                                      start >> PAGE_CACHE_SHIFT);
185                 btrfs_set_file_extent_compression(leaf, ei, 0);
186                 kaddr = kmap_atomic(page, KM_USER0);
187                 offset = start & (PAGE_CACHE_SIZE - 1);
188                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
189                 kunmap_atomic(kaddr, KM_USER0);
190                 page_cache_release(page);
191         }
192         btrfs_mark_buffer_dirty(leaf);
193         btrfs_free_path(path);
194
195         /*
196          * we're an inline extent, so nobody can
197          * extend the file past i_size without locking
198          * a page we already have locked.
199          *
200          * We must do any isize and inode updates
201          * before we unlock the pages.  Otherwise we
202          * could end up racing with unlink.
203          */
204         BTRFS_I(inode)->disk_i_size = inode->i_size;
205         btrfs_update_inode(trans, root, inode);
206
207         return 0;
208 fail:
209         btrfs_free_path(path);
210         return err;
211 }
212
213
214 /*
215  * conditionally insert an inline extent into the file.  This
216  * does the checks required to make sure the data is small enough
217  * to fit as an inline extent.
218  */
219 static noinline int cow_file_range_inline(struct btrfs_trans_handle *trans,
220                                  struct btrfs_root *root,
221                                  struct inode *inode, u64 start, u64 end,
222                                  size_t compressed_size, int compress_type,
223                                  struct page **compressed_pages)
224 {
225         u64 isize = i_size_read(inode);
226         u64 actual_end = min(end + 1, isize);
227         u64 inline_len = actual_end - start;
228         u64 aligned_end = (end + root->sectorsize - 1) &
229                         ~((u64)root->sectorsize - 1);
230         u64 hint_byte;
231         u64 data_len = inline_len;
232         int ret;
233
234         if (compressed_size)
235                 data_len = compressed_size;
236
237         if (start > 0 ||
238             actual_end >= PAGE_CACHE_SIZE ||
239             data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
240             (!compressed_size &&
241             (actual_end & (root->sectorsize - 1)) == 0) ||
242             end + 1 < isize ||
243             data_len > root->fs_info->max_inline) {
244                 return 1;
245         }
246
247         ret = btrfs_drop_extents(trans, inode, start, aligned_end,
248                                  &hint_byte, 1);
249         BUG_ON(ret);
250
251         if (isize > actual_end)
252                 inline_len = min_t(u64, isize, actual_end);
253         ret = insert_inline_extent(trans, root, inode, start,
254                                    inline_len, compressed_size,
255                                    compress_type, compressed_pages);
256         BUG_ON(ret);
257         btrfs_delalloc_release_metadata(inode, end + 1 - start);
258         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
259         return 0;
260 }
261
262 struct async_extent {
263         u64 start;
264         u64 ram_size;
265         u64 compressed_size;
266         struct page **pages;
267         unsigned long nr_pages;
268         int compress_type;
269         struct list_head list;
270 };
271
272 struct async_cow {
273         struct inode *inode;
274         struct btrfs_root *root;
275         struct page *locked_page;
276         u64 start;
277         u64 end;
278         struct list_head extents;
279         struct btrfs_work work;
280 };
281
282 static noinline int add_async_extent(struct async_cow *cow,
283                                      u64 start, u64 ram_size,
284                                      u64 compressed_size,
285                                      struct page **pages,
286                                      unsigned long nr_pages,
287                                      int compress_type)
288 {
289         struct async_extent *async_extent;
290
291         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
292         BUG_ON(!async_extent);
293         async_extent->start = start;
294         async_extent->ram_size = ram_size;
295         async_extent->compressed_size = compressed_size;
296         async_extent->pages = pages;
297         async_extent->nr_pages = nr_pages;
298         async_extent->compress_type = compress_type;
299         list_add_tail(&async_extent->list, &cow->extents);
300         return 0;
301 }
302
303 /*
304  * we create compressed extents in two phases.  The first
305  * phase compresses a range of pages that have already been
306  * locked (both pages and state bits are locked).
307  *
308  * This is done inside an ordered work queue, and the compression
309  * is spread across many cpus.  The actual IO submission is step
310  * two, and the ordered work queue takes care of making sure that
311  * happens in the same order things were put onto the queue by
312  * writepages and friends.
313  *
314  * If this code finds it can't get good compression, it puts an
315  * entry onto the work queue to write the uncompressed bytes.  This
316  * makes sure that both compressed inodes and uncompressed inodes
317  * are written in the same order that pdflush sent them down.
318  */
319 static noinline int compress_file_range(struct inode *inode,
320                                         struct page *locked_page,
321                                         u64 start, u64 end,
322                                         struct async_cow *async_cow,
323                                         int *num_added)
324 {
325         struct btrfs_root *root = BTRFS_I(inode)->root;
326         struct btrfs_trans_handle *trans;
327         u64 num_bytes;
328         u64 blocksize = root->sectorsize;
329         u64 actual_end;
330         u64 isize = i_size_read(inode);
331         int ret = 0;
332         struct page **pages = NULL;
333         unsigned long nr_pages;
334         unsigned long nr_pages_ret = 0;
335         unsigned long total_compressed = 0;
336         unsigned long total_in = 0;
337         unsigned long max_compressed = 128 * 1024;
338         unsigned long max_uncompressed = 128 * 1024;
339         int i;
340         int will_compress;
341         int compress_type = root->fs_info->compress_type;
342
343         actual_end = min_t(u64, isize, end + 1);
344 again:
345         will_compress = 0;
346         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
347         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
348
349         /*
350          * we don't want to send crud past the end of i_size through
351          * compression, that's just a waste of CPU time.  So, if the
352          * end of the file is before the start of our current
353          * requested range of bytes, we bail out to the uncompressed
354          * cleanup code that can deal with all of this.
355          *
356          * It isn't really the fastest way to fix things, but this is a
357          * very uncommon corner.
358          */
359         if (actual_end <= start)
360                 goto cleanup_and_bail_uncompressed;
361
362         total_compressed = actual_end - start;
363
364         /* we want to make sure that amount of ram required to uncompress
365          * an extent is reasonable, so we limit the total size in ram
366          * of a compressed extent to 128k.  This is a crucial number
367          * because it also controls how easily we can spread reads across
368          * cpus for decompression.
369          *
370          * We also want to make sure the amount of IO required to do
371          * a random read is reasonably small, so we limit the size of
372          * a compressed extent to 128k.
373          */
374         total_compressed = min(total_compressed, max_uncompressed);
375         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
376         num_bytes = max(blocksize,  num_bytes);
377         total_in = 0;
378         ret = 0;
379
380         /*
381          * we do compression for mount -o compress and when the
382          * inode has not been flagged as nocompress.  This flag can
383          * change at any time if we discover bad compression ratios.
384          */
385         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS) &&
386             (btrfs_test_opt(root, COMPRESS) ||
387              (BTRFS_I(inode)->force_compress) ||
388              (BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))) {
389                 WARN_ON(pages);
390                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
391                 BUG_ON(!pages);
392
393                 if (BTRFS_I(inode)->force_compress)
394                         compress_type = BTRFS_I(inode)->force_compress;
395
396                 ret = btrfs_compress_pages(compress_type,
397                                            inode->i_mapping, start,
398                                            total_compressed, pages,
399                                            nr_pages, &nr_pages_ret,
400                                            &total_in,
401                                            &total_compressed,
402                                            max_compressed);
403
404                 if (!ret) {
405                         unsigned long offset = total_compressed &
406                                 (PAGE_CACHE_SIZE - 1);
407                         struct page *page = pages[nr_pages_ret - 1];
408                         char *kaddr;
409
410                         /* zero the tail end of the last page, we might be
411                          * sending it down to disk
412                          */
413                         if (offset) {
414                                 kaddr = kmap_atomic(page, KM_USER0);
415                                 memset(kaddr + offset, 0,
416                                        PAGE_CACHE_SIZE - offset);
417                                 kunmap_atomic(kaddr, KM_USER0);
418                         }
419                         will_compress = 1;
420                 }
421         }
422         if (start == 0) {
423                 trans = btrfs_join_transaction(root, 1);
424                 BUG_ON(IS_ERR(trans));
425                 btrfs_set_trans_block_group(trans, inode);
426                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
427
428                 /* lets try to make an inline extent */
429                 if (ret || total_in < (actual_end - start)) {
430                         /* we didn't compress the entire range, try
431                          * to make an uncompressed inline extent.
432                          */
433                         ret = cow_file_range_inline(trans, root, inode,
434                                                     start, end, 0, 0, NULL);
435                 } else {
436                         /* try making a compressed inline extent */
437                         ret = cow_file_range_inline(trans, root, inode,
438                                                     start, end,
439                                                     total_compressed,
440                                                     compress_type, pages);
441                 }
442                 if (ret == 0) {
443                         /*
444                          * inline extent creation worked, we don't need
445                          * to create any more async work items.  Unlock
446                          * and free up our temp pages.
447                          */
448                         extent_clear_unlock_delalloc(inode,
449                              &BTRFS_I(inode)->io_tree,
450                              start, end, NULL,
451                              EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
452                              EXTENT_CLEAR_DELALLOC |
453                              EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK);
454
455                         btrfs_end_transaction(trans, root);
456                         goto free_pages_out;
457                 }
458                 btrfs_end_transaction(trans, root);
459         }
460
461         if (will_compress) {
462                 /*
463                  * we aren't doing an inline extent round the compressed size
464                  * up to a block size boundary so the allocator does sane
465                  * things
466                  */
467                 total_compressed = (total_compressed + blocksize - 1) &
468                         ~(blocksize - 1);
469
470                 /*
471                  * one last check to make sure the compression is really a
472                  * win, compare the page count read with the blocks on disk
473                  */
474                 total_in = (total_in + PAGE_CACHE_SIZE - 1) &
475                         ~(PAGE_CACHE_SIZE - 1);
476                 if (total_compressed >= total_in) {
477                         will_compress = 0;
478                 } else {
479                         num_bytes = total_in;
480                 }
481         }
482         if (!will_compress && pages) {
483                 /*
484                  * the compression code ran but failed to make things smaller,
485                  * free any pages it allocated and our page pointer array
486                  */
487                 for (i = 0; i < nr_pages_ret; i++) {
488                         WARN_ON(pages[i]->mapping);
489                         page_cache_release(pages[i]);
490                 }
491                 kfree(pages);
492                 pages = NULL;
493                 total_compressed = 0;
494                 nr_pages_ret = 0;
495
496                 /* flag the file so we don't compress in the future */
497                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
498                     !(BTRFS_I(inode)->force_compress)) {
499                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
500                 }
501         }
502         if (will_compress) {
503                 *num_added += 1;
504
505                 /* the async work queues will take care of doing actual
506                  * allocation on disk for these compressed pages,
507                  * and will submit them to the elevator.
508                  */
509                 add_async_extent(async_cow, start, num_bytes,
510                                  total_compressed, pages, nr_pages_ret,
511                                  compress_type);
512
513                 if (start + num_bytes < end) {
514                         start += num_bytes;
515                         pages = NULL;
516                         cond_resched();
517                         goto again;
518                 }
519         } else {
520 cleanup_and_bail_uncompressed:
521                 /*
522                  * No compression, but we still need to write the pages in
523                  * the file we've been given so far.  redirty the locked
524                  * page if it corresponds to our extent and set things up
525                  * for the async work queue to run cow_file_range to do
526                  * the normal delalloc dance
527                  */
528                 if (page_offset(locked_page) >= start &&
529                     page_offset(locked_page) <= end) {
530                         __set_page_dirty_nobuffers(locked_page);
531                         /* unlocked later on in the async handlers */
532                 }
533                 add_async_extent(async_cow, start, end - start + 1,
534                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
535                 *num_added += 1;
536         }
537
538 out:
539         return 0;
540
541 free_pages_out:
542         for (i = 0; i < nr_pages_ret; i++) {
543                 WARN_ON(pages[i]->mapping);
544                 page_cache_release(pages[i]);
545         }
546         kfree(pages);
547
548         goto out;
549 }
550
551 /*
552  * phase two of compressed writeback.  This is the ordered portion
553  * of the code, which only gets called in the order the work was
554  * queued.  We walk all the async extents created by compress_file_range
555  * and send them down to the disk.
556  */
557 static noinline int submit_compressed_extents(struct inode *inode,
558                                               struct async_cow *async_cow)
559 {
560         struct async_extent *async_extent;
561         u64 alloc_hint = 0;
562         struct btrfs_trans_handle *trans;
563         struct btrfs_key ins;
564         struct extent_map *em;
565         struct btrfs_root *root = BTRFS_I(inode)->root;
566         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
567         struct extent_io_tree *io_tree;
568         int ret = 0;
569
570         if (list_empty(&async_cow->extents))
571                 return 0;
572
573
574         while (!list_empty(&async_cow->extents)) {
575                 async_extent = list_entry(async_cow->extents.next,
576                                           struct async_extent, list);
577                 list_del(&async_extent->list);
578
579                 io_tree = &BTRFS_I(inode)->io_tree;
580
581 retry:
582                 /* did the compression code fall back to uncompressed IO? */
583                 if (!async_extent->pages) {
584                         int page_started = 0;
585                         unsigned long nr_written = 0;
586
587                         lock_extent(io_tree, async_extent->start,
588                                          async_extent->start +
589                                          async_extent->ram_size - 1, GFP_NOFS);
590
591                         /* allocate blocks */
592                         ret = cow_file_range(inode, async_cow->locked_page,
593                                              async_extent->start,
594                                              async_extent->start +
595                                              async_extent->ram_size - 1,
596                                              &page_started, &nr_written, 0);
597
598                         /*
599                          * if page_started, cow_file_range inserted an
600                          * inline extent and took care of all the unlocking
601                          * and IO for us.  Otherwise, we need to submit
602                          * all those pages down to the drive.
603                          */
604                         if (!page_started && !ret)
605                                 extent_write_locked_range(io_tree,
606                                                   inode, async_extent->start,
607                                                   async_extent->start +
608                                                   async_extent->ram_size - 1,
609                                                   btrfs_get_extent,
610                                                   WB_SYNC_ALL);
611                         kfree(async_extent);
612                         cond_resched();
613                         continue;
614                 }
615
616                 lock_extent(io_tree, async_extent->start,
617                             async_extent->start + async_extent->ram_size - 1,
618                             GFP_NOFS);
619
620                 trans = btrfs_join_transaction(root, 1);
621                 BUG_ON(IS_ERR(trans));
622                 ret = btrfs_reserve_extent(trans, root,
623                                            async_extent->compressed_size,
624                                            async_extent->compressed_size,
625                                            0, alloc_hint,
626                                            (u64)-1, &ins, 1);
627                 btrfs_end_transaction(trans, root);
628
629                 if (ret) {
630                         int i;
631                         for (i = 0; i < async_extent->nr_pages; i++) {
632                                 WARN_ON(async_extent->pages[i]->mapping);
633                                 page_cache_release(async_extent->pages[i]);
634                         }
635                         kfree(async_extent->pages);
636                         async_extent->nr_pages = 0;
637                         async_extent->pages = NULL;
638                         unlock_extent(io_tree, async_extent->start,
639                                       async_extent->start +
640                                       async_extent->ram_size - 1, GFP_NOFS);
641                         goto retry;
642                 }
643
644                 /*
645                  * here we're doing allocation and writeback of the
646                  * compressed pages
647                  */
648                 btrfs_drop_extent_cache(inode, async_extent->start,
649                                         async_extent->start +
650                                         async_extent->ram_size - 1, 0);
651
652                 em = alloc_extent_map(GFP_NOFS);
653                 BUG_ON(!em);
654                 em->start = async_extent->start;
655                 em->len = async_extent->ram_size;
656                 em->orig_start = em->start;
657
658                 em->block_start = ins.objectid;
659                 em->block_len = ins.offset;
660                 em->bdev = root->fs_info->fs_devices->latest_bdev;
661                 em->compress_type = async_extent->compress_type;
662                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
663                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
664
665                 while (1) {
666                         write_lock(&em_tree->lock);
667                         ret = add_extent_mapping(em_tree, em);
668                         write_unlock(&em_tree->lock);
669                         if (ret != -EEXIST) {
670                                 free_extent_map(em);
671                                 break;
672                         }
673                         btrfs_drop_extent_cache(inode, async_extent->start,
674                                                 async_extent->start +
675                                                 async_extent->ram_size - 1, 0);
676                 }
677
678                 ret = btrfs_add_ordered_extent_compress(inode,
679                                                 async_extent->start,
680                                                 ins.objectid,
681                                                 async_extent->ram_size,
682                                                 ins.offset,
683                                                 BTRFS_ORDERED_COMPRESSED,
684                                                 async_extent->compress_type);
685                 BUG_ON(ret);
686
687                 /*
688                  * clear dirty, set writeback and unlock the pages.
689                  */
690                 extent_clear_unlock_delalloc(inode,
691                                 &BTRFS_I(inode)->io_tree,
692                                 async_extent->start,
693                                 async_extent->start +
694                                 async_extent->ram_size - 1,
695                                 NULL, EXTENT_CLEAR_UNLOCK_PAGE |
696                                 EXTENT_CLEAR_UNLOCK |
697                                 EXTENT_CLEAR_DELALLOC |
698                                 EXTENT_CLEAR_DIRTY | EXTENT_SET_WRITEBACK);
699
700                 ret = btrfs_submit_compressed_write(inode,
701                                     async_extent->start,
702                                     async_extent->ram_size,
703                                     ins.objectid,
704                                     ins.offset, async_extent->pages,
705                                     async_extent->nr_pages);
706
707                 BUG_ON(ret);
708                 alloc_hint = ins.objectid + ins.offset;
709                 kfree(async_extent);
710                 cond_resched();
711         }
712
713         return 0;
714 }
715
716 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
717                                       u64 num_bytes)
718 {
719         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
720         struct extent_map *em;
721         u64 alloc_hint = 0;
722
723         read_lock(&em_tree->lock);
724         em = search_extent_mapping(em_tree, start, num_bytes);
725         if (em) {
726                 /*
727                  * if block start isn't an actual block number then find the
728                  * first block in this inode and use that as a hint.  If that
729                  * block is also bogus then just don't worry about it.
730                  */
731                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
732                         free_extent_map(em);
733                         em = search_extent_mapping(em_tree, 0, 0);
734                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
735                                 alloc_hint = em->block_start;
736                         if (em)
737                                 free_extent_map(em);
738                 } else {
739                         alloc_hint = em->block_start;
740                         free_extent_map(em);
741                 }
742         }
743         read_unlock(&em_tree->lock);
744
745         return alloc_hint;
746 }
747
748 /*
749  * when extent_io.c finds a delayed allocation range in the file,
750  * the call backs end up in this code.  The basic idea is to
751  * allocate extents on disk for the range, and create ordered data structs
752  * in ram to track those extents.
753  *
754  * locked_page is the page that writepage had locked already.  We use
755  * it to make sure we don't do extra locks or unlocks.
756  *
757  * *page_started is set to one if we unlock locked_page and do everything
758  * required to start IO on it.  It may be clean and already done with
759  * IO when we return.
760  */
761 static noinline int cow_file_range(struct inode *inode,
762                                    struct page *locked_page,
763                                    u64 start, u64 end, int *page_started,
764                                    unsigned long *nr_written,
765                                    int unlock)
766 {
767         struct btrfs_root *root = BTRFS_I(inode)->root;
768         struct btrfs_trans_handle *trans;
769         u64 alloc_hint = 0;
770         u64 num_bytes;
771         unsigned long ram_size;
772         u64 disk_num_bytes;
773         u64 cur_alloc_size;
774         u64 blocksize = root->sectorsize;
775         struct btrfs_key ins;
776         struct extent_map *em;
777         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
778         int ret = 0;
779
780         BUG_ON(root == root->fs_info->tree_root);
781         trans = btrfs_join_transaction(root, 1);
782         BUG_ON(IS_ERR(trans));
783         btrfs_set_trans_block_group(trans, inode);
784         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
785
786         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
787         num_bytes = max(blocksize,  num_bytes);
788         disk_num_bytes = num_bytes;
789         ret = 0;
790
791         if (start == 0) {
792                 /* lets try to make an inline extent */
793                 ret = cow_file_range_inline(trans, root, inode,
794                                             start, end, 0, 0, NULL);
795                 if (ret == 0) {
796                         extent_clear_unlock_delalloc(inode,
797                                      &BTRFS_I(inode)->io_tree,
798                                      start, end, NULL,
799                                      EXTENT_CLEAR_UNLOCK_PAGE |
800                                      EXTENT_CLEAR_UNLOCK |
801                                      EXTENT_CLEAR_DELALLOC |
802                                      EXTENT_CLEAR_DIRTY |
803                                      EXTENT_SET_WRITEBACK |
804                                      EXTENT_END_WRITEBACK);
805
806                         *nr_written = *nr_written +
807                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
808                         *page_started = 1;
809                         ret = 0;
810                         goto out;
811                 }
812         }
813
814         BUG_ON(disk_num_bytes >
815                btrfs_super_total_bytes(&root->fs_info->super_copy));
816
817         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
818         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
819
820         while (disk_num_bytes > 0) {
821                 unsigned long op;
822
823                 cur_alloc_size = disk_num_bytes;
824                 ret = btrfs_reserve_extent(trans, root, cur_alloc_size,
825                                            root->sectorsize, 0, alloc_hint,
826                                            (u64)-1, &ins, 1);
827                 BUG_ON(ret);
828
829                 em = alloc_extent_map(GFP_NOFS);
830                 BUG_ON(!em);
831                 em->start = start;
832                 em->orig_start = em->start;
833                 ram_size = ins.offset;
834                 em->len = ins.offset;
835
836                 em->block_start = ins.objectid;
837                 em->block_len = ins.offset;
838                 em->bdev = root->fs_info->fs_devices->latest_bdev;
839                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
840
841                 while (1) {
842                         write_lock(&em_tree->lock);
843                         ret = add_extent_mapping(em_tree, em);
844                         write_unlock(&em_tree->lock);
845                         if (ret != -EEXIST) {
846                                 free_extent_map(em);
847                                 break;
848                         }
849                         btrfs_drop_extent_cache(inode, start,
850                                                 start + ram_size - 1, 0);
851                 }
852
853                 cur_alloc_size = ins.offset;
854                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
855                                                ram_size, cur_alloc_size, 0);
856                 BUG_ON(ret);
857
858                 if (root->root_key.objectid ==
859                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
860                         ret = btrfs_reloc_clone_csums(inode, start,
861                                                       cur_alloc_size);
862                         BUG_ON(ret);
863                 }
864
865                 if (disk_num_bytes < cur_alloc_size)
866                         break;
867
868                 /* we're not doing compressed IO, don't unlock the first
869                  * page (which the caller expects to stay locked), don't
870                  * clear any dirty bits and don't set any writeback bits
871                  *
872                  * Do set the Private2 bit so we know this page was properly
873                  * setup for writepage
874                  */
875                 op = unlock ? EXTENT_CLEAR_UNLOCK_PAGE : 0;
876                 op |= EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
877                         EXTENT_SET_PRIVATE2;
878
879                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
880                                              start, start + ram_size - 1,
881                                              locked_page, op);
882                 disk_num_bytes -= cur_alloc_size;
883                 num_bytes -= cur_alloc_size;
884                 alloc_hint = ins.objectid + ins.offset;
885                 start += cur_alloc_size;
886         }
887 out:
888         ret = 0;
889         btrfs_end_transaction(trans, root);
890
891         return ret;
892 }
893
894 /*
895  * work queue call back to started compression on a file and pages
896  */
897 static noinline void async_cow_start(struct btrfs_work *work)
898 {
899         struct async_cow *async_cow;
900         int num_added = 0;
901         async_cow = container_of(work, struct async_cow, work);
902
903         compress_file_range(async_cow->inode, async_cow->locked_page,
904                             async_cow->start, async_cow->end, async_cow,
905                             &num_added);
906         if (num_added == 0)
907                 async_cow->inode = NULL;
908 }
909
910 /*
911  * work queue call back to submit previously compressed pages
912  */
913 static noinline void async_cow_submit(struct btrfs_work *work)
914 {
915         struct async_cow *async_cow;
916         struct btrfs_root *root;
917         unsigned long nr_pages;
918
919         async_cow = container_of(work, struct async_cow, work);
920
921         root = async_cow->root;
922         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
923                 PAGE_CACHE_SHIFT;
924
925         atomic_sub(nr_pages, &root->fs_info->async_delalloc_pages);
926
927         if (atomic_read(&root->fs_info->async_delalloc_pages) <
928             5 * 1042 * 1024 &&
929             waitqueue_active(&root->fs_info->async_submit_wait))
930                 wake_up(&root->fs_info->async_submit_wait);
931
932         if (async_cow->inode)
933                 submit_compressed_extents(async_cow->inode, async_cow);
934 }
935
936 static noinline void async_cow_free(struct btrfs_work *work)
937 {
938         struct async_cow *async_cow;
939         async_cow = container_of(work, struct async_cow, work);
940         kfree(async_cow);
941 }
942
943 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
944                                 u64 start, u64 end, int *page_started,
945                                 unsigned long *nr_written)
946 {
947         struct async_cow *async_cow;
948         struct btrfs_root *root = BTRFS_I(inode)->root;
949         unsigned long nr_pages;
950         u64 cur_end;
951         int limit = 10 * 1024 * 1042;
952
953         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
954                          1, 0, NULL, GFP_NOFS);
955         while (start < end) {
956                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
957                 BUG_ON(!async_cow);
958                 async_cow->inode = inode;
959                 async_cow->root = root;
960                 async_cow->locked_page = locked_page;
961                 async_cow->start = start;
962
963                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
964                         cur_end = end;
965                 else
966                         cur_end = min(end, start + 512 * 1024 - 1);
967
968                 async_cow->end = cur_end;
969                 INIT_LIST_HEAD(&async_cow->extents);
970
971                 async_cow->work.func = async_cow_start;
972                 async_cow->work.ordered_func = async_cow_submit;
973                 async_cow->work.ordered_free = async_cow_free;
974                 async_cow->work.flags = 0;
975
976                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
977                         PAGE_CACHE_SHIFT;
978                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
979
980                 btrfs_queue_worker(&root->fs_info->delalloc_workers,
981                                    &async_cow->work);
982
983                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
984                         wait_event(root->fs_info->async_submit_wait,
985                            (atomic_read(&root->fs_info->async_delalloc_pages) <
986                             limit));
987                 }
988
989                 while (atomic_read(&root->fs_info->async_submit_draining) &&
990                       atomic_read(&root->fs_info->async_delalloc_pages)) {
991                         wait_event(root->fs_info->async_submit_wait,
992                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
993                            0));
994                 }
995
996                 *nr_written += nr_pages;
997                 start = cur_end + 1;
998         }
999         *page_started = 1;
1000         return 0;
1001 }
1002
1003 static noinline int csum_exist_in_range(struct btrfs_root *root,
1004                                         u64 bytenr, u64 num_bytes)
1005 {
1006         int ret;
1007         struct btrfs_ordered_sum *sums;
1008         LIST_HEAD(list);
1009
1010         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1011                                        bytenr + num_bytes - 1, &list);
1012         if (ret == 0 && list_empty(&list))
1013                 return 0;
1014
1015         while (!list_empty(&list)) {
1016                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1017                 list_del(&sums->list);
1018                 kfree(sums);
1019         }
1020         return 1;
1021 }
1022
1023 /*
1024  * when nowcow writeback call back.  This checks for snapshots or COW copies
1025  * of the extents that exist in the file, and COWs the file as required.
1026  *
1027  * If no cow copies or snapshots exist, we write directly to the existing
1028  * blocks on disk
1029  */
1030 static noinline int run_delalloc_nocow(struct inode *inode,
1031                                        struct page *locked_page,
1032                               u64 start, u64 end, int *page_started, int force,
1033                               unsigned long *nr_written)
1034 {
1035         struct btrfs_root *root = BTRFS_I(inode)->root;
1036         struct btrfs_trans_handle *trans;
1037         struct extent_buffer *leaf;
1038         struct btrfs_path *path;
1039         struct btrfs_file_extent_item *fi;
1040         struct btrfs_key found_key;
1041         u64 cow_start;
1042         u64 cur_offset;
1043         u64 extent_end;
1044         u64 extent_offset;
1045         u64 disk_bytenr;
1046         u64 num_bytes;
1047         int extent_type;
1048         int ret;
1049         int type;
1050         int nocow;
1051         int check_prev = 1;
1052         bool nolock = false;
1053
1054         path = btrfs_alloc_path();
1055         BUG_ON(!path);
1056         if (root == root->fs_info->tree_root) {
1057                 nolock = true;
1058                 trans = btrfs_join_transaction_nolock(root, 1);
1059         } else {
1060                 trans = btrfs_join_transaction(root, 1);
1061         }
1062         BUG_ON(IS_ERR(trans));
1063
1064         cow_start = (u64)-1;
1065         cur_offset = start;
1066         while (1) {
1067                 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
1068                                                cur_offset, 0);
1069                 BUG_ON(ret < 0);
1070                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1071                         leaf = path->nodes[0];
1072                         btrfs_item_key_to_cpu(leaf, &found_key,
1073                                               path->slots[0] - 1);
1074                         if (found_key.objectid == inode->i_ino &&
1075                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1076                                 path->slots[0]--;
1077                 }
1078                 check_prev = 0;
1079 next_slot:
1080                 leaf = path->nodes[0];
1081                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1082                         ret = btrfs_next_leaf(root, path);
1083                         if (ret < 0)
1084                                 BUG_ON(1);
1085                         if (ret > 0)
1086                                 break;
1087                         leaf = path->nodes[0];
1088                 }
1089
1090                 nocow = 0;
1091                 disk_bytenr = 0;
1092                 num_bytes = 0;
1093                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1094
1095                 if (found_key.objectid > inode->i_ino ||
1096                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1097                     found_key.offset > end)
1098                         break;
1099
1100                 if (found_key.offset > cur_offset) {
1101                         extent_end = found_key.offset;
1102                         extent_type = 0;
1103                         goto out_check;
1104                 }
1105
1106                 fi = btrfs_item_ptr(leaf, path->slots[0],
1107                                     struct btrfs_file_extent_item);
1108                 extent_type = btrfs_file_extent_type(leaf, fi);
1109
1110                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1111                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1112                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1113                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1114                         extent_end = found_key.offset +
1115                                 btrfs_file_extent_num_bytes(leaf, fi);
1116                         if (extent_end <= start) {
1117                                 path->slots[0]++;
1118                                 goto next_slot;
1119                         }
1120                         if (disk_bytenr == 0)
1121                                 goto out_check;
1122                         if (btrfs_file_extent_compression(leaf, fi) ||
1123                             btrfs_file_extent_encryption(leaf, fi) ||
1124                             btrfs_file_extent_other_encoding(leaf, fi))
1125                                 goto out_check;
1126                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1127                                 goto out_check;
1128                         if (btrfs_extent_readonly(root, disk_bytenr))
1129                                 goto out_check;
1130                         if (btrfs_cross_ref_exist(trans, root, inode->i_ino,
1131                                                   found_key.offset -
1132                                                   extent_offset, disk_bytenr))
1133                                 goto out_check;
1134                         disk_bytenr += extent_offset;
1135                         disk_bytenr += cur_offset - found_key.offset;
1136                         num_bytes = min(end + 1, extent_end) - cur_offset;
1137                         /*
1138                          * force cow if csum exists in the range.
1139                          * this ensure that csum for a given extent are
1140                          * either valid or do not exist.
1141                          */
1142                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1143                                 goto out_check;
1144                         nocow = 1;
1145                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1146                         extent_end = found_key.offset +
1147                                 btrfs_file_extent_inline_len(leaf, fi);
1148                         extent_end = ALIGN(extent_end, root->sectorsize);
1149                 } else {
1150                         BUG_ON(1);
1151                 }
1152 out_check:
1153                 if (extent_end <= start) {
1154                         path->slots[0]++;
1155                         goto next_slot;
1156                 }
1157                 if (!nocow) {
1158                         if (cow_start == (u64)-1)
1159                                 cow_start = cur_offset;
1160                         cur_offset = extent_end;
1161                         if (cur_offset > end)
1162                                 break;
1163                         path->slots[0]++;
1164                         goto next_slot;
1165                 }
1166
1167                 btrfs_release_path(root, path);
1168                 if (cow_start != (u64)-1) {
1169                         ret = cow_file_range(inode, locked_page, cow_start,
1170                                         found_key.offset - 1, page_started,
1171                                         nr_written, 1);
1172                         BUG_ON(ret);
1173                         cow_start = (u64)-1;
1174                 }
1175
1176                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1177                         struct extent_map *em;
1178                         struct extent_map_tree *em_tree;
1179                         em_tree = &BTRFS_I(inode)->extent_tree;
1180                         em = alloc_extent_map(GFP_NOFS);
1181                         BUG_ON(!em);
1182                         em->start = cur_offset;
1183                         em->orig_start = em->start;
1184                         em->len = num_bytes;
1185                         em->block_len = num_bytes;
1186                         em->block_start = disk_bytenr;
1187                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1188                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1189                         while (1) {
1190                                 write_lock(&em_tree->lock);
1191                                 ret = add_extent_mapping(em_tree, em);
1192                                 write_unlock(&em_tree->lock);
1193                                 if (ret != -EEXIST) {
1194                                         free_extent_map(em);
1195                                         break;
1196                                 }
1197                                 btrfs_drop_extent_cache(inode, em->start,
1198                                                 em->start + em->len - 1, 0);
1199                         }
1200                         type = BTRFS_ORDERED_PREALLOC;
1201                 } else {
1202                         type = BTRFS_ORDERED_NOCOW;
1203                 }
1204
1205                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1206                                                num_bytes, num_bytes, type);
1207                 BUG_ON(ret);
1208
1209                 if (root->root_key.objectid ==
1210                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1211                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1212                                                       num_bytes);
1213                         BUG_ON(ret);
1214                 }
1215
1216                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
1217                                 cur_offset, cur_offset + num_bytes - 1,
1218                                 locked_page, EXTENT_CLEAR_UNLOCK_PAGE |
1219                                 EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
1220                                 EXTENT_SET_PRIVATE2);
1221                 cur_offset = extent_end;
1222                 if (cur_offset > end)
1223                         break;
1224         }
1225         btrfs_release_path(root, path);
1226
1227         if (cur_offset <= end && cow_start == (u64)-1)
1228                 cow_start = cur_offset;
1229         if (cow_start != (u64)-1) {
1230                 ret = cow_file_range(inode, locked_page, cow_start, end,
1231                                      page_started, nr_written, 1);
1232                 BUG_ON(ret);
1233         }
1234
1235         if (nolock) {
1236                 ret = btrfs_end_transaction_nolock(trans, root);
1237                 BUG_ON(ret);
1238         } else {
1239                 ret = btrfs_end_transaction(trans, root);
1240                 BUG_ON(ret);
1241         }
1242         btrfs_free_path(path);
1243         return 0;
1244 }
1245
1246 /*
1247  * extent_io.c call back to do delayed allocation processing
1248  */
1249 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1250                               u64 start, u64 end, int *page_started,
1251                               unsigned long *nr_written)
1252 {
1253         int ret;
1254         struct btrfs_root *root = BTRFS_I(inode)->root;
1255
1256         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW)
1257                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1258                                          page_started, 1, nr_written);
1259         else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC)
1260                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1261                                          page_started, 0, nr_written);
1262         else if (!btrfs_test_opt(root, COMPRESS) &&
1263                  !(BTRFS_I(inode)->force_compress) &&
1264                  !(BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))
1265                 ret = cow_file_range(inode, locked_page, start, end,
1266                                       page_started, nr_written, 1);
1267         else
1268                 ret = cow_file_range_async(inode, locked_page, start, end,
1269                                            page_started, nr_written);
1270         return ret;
1271 }
1272
1273 static int btrfs_split_extent_hook(struct inode *inode,
1274                                    struct extent_state *orig, u64 split)
1275 {
1276         /* not delalloc, ignore it */
1277         if (!(orig->state & EXTENT_DELALLOC))
1278                 return 0;
1279
1280         atomic_inc(&BTRFS_I(inode)->outstanding_extents);
1281         return 0;
1282 }
1283
1284 /*
1285  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1286  * extents so we can keep track of new extents that are just merged onto old
1287  * extents, such as when we are doing sequential writes, so we can properly
1288  * account for the metadata space we'll need.
1289  */
1290 static int btrfs_merge_extent_hook(struct inode *inode,
1291                                    struct extent_state *new,
1292                                    struct extent_state *other)
1293 {
1294         /* not delalloc, ignore it */
1295         if (!(other->state & EXTENT_DELALLOC))
1296                 return 0;
1297
1298         atomic_dec(&BTRFS_I(inode)->outstanding_extents);
1299         return 0;
1300 }
1301
1302 /*
1303  * extent_io.c set_bit_hook, used to track delayed allocation
1304  * bytes in this file, and to maintain the list of inodes that
1305  * have pending delalloc work to be done.
1306  */
1307 static int btrfs_set_bit_hook(struct inode *inode,
1308                               struct extent_state *state, int *bits)
1309 {
1310
1311         /*
1312          * set_bit and clear bit hooks normally require _irqsave/restore
1313          * but in this case, we are only testeing for the DELALLOC
1314          * bit, which is only set or cleared with irqs on
1315          */
1316         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1317                 struct btrfs_root *root = BTRFS_I(inode)->root;
1318                 u64 len = state->end + 1 - state->start;
1319                 int do_list = (root->root_key.objectid !=
1320                                BTRFS_ROOT_TREE_OBJECTID);
1321
1322                 if (*bits & EXTENT_FIRST_DELALLOC)
1323                         *bits &= ~EXTENT_FIRST_DELALLOC;
1324                 else
1325                         atomic_inc(&BTRFS_I(inode)->outstanding_extents);
1326
1327                 spin_lock(&root->fs_info->delalloc_lock);
1328                 BTRFS_I(inode)->delalloc_bytes += len;
1329                 root->fs_info->delalloc_bytes += len;
1330                 if (do_list && list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1331                         list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1332                                       &root->fs_info->delalloc_inodes);
1333                 }
1334                 spin_unlock(&root->fs_info->delalloc_lock);
1335         }
1336         return 0;
1337 }
1338
1339 /*
1340  * extent_io.c clear_bit_hook, see set_bit_hook for why
1341  */
1342 static int btrfs_clear_bit_hook(struct inode *inode,
1343                                 struct extent_state *state, int *bits)
1344 {
1345         /*
1346          * set_bit and clear bit hooks normally require _irqsave/restore
1347          * but in this case, we are only testeing for the DELALLOC
1348          * bit, which is only set or cleared with irqs on
1349          */
1350         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1351                 struct btrfs_root *root = BTRFS_I(inode)->root;
1352                 u64 len = state->end + 1 - state->start;
1353                 int do_list = (root->root_key.objectid !=
1354                                BTRFS_ROOT_TREE_OBJECTID);
1355
1356                 if (*bits & EXTENT_FIRST_DELALLOC)
1357                         *bits &= ~EXTENT_FIRST_DELALLOC;
1358                 else if (!(*bits & EXTENT_DO_ACCOUNTING))
1359                         atomic_dec(&BTRFS_I(inode)->outstanding_extents);
1360
1361                 if (*bits & EXTENT_DO_ACCOUNTING)
1362                         btrfs_delalloc_release_metadata(inode, len);
1363
1364                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1365                     && do_list)
1366                         btrfs_free_reserved_data_space(inode, len);
1367
1368                 spin_lock(&root->fs_info->delalloc_lock);
1369                 root->fs_info->delalloc_bytes -= len;
1370                 BTRFS_I(inode)->delalloc_bytes -= len;
1371
1372                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1373                     !list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1374                         list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1375                 }
1376                 spin_unlock(&root->fs_info->delalloc_lock);
1377         }
1378         return 0;
1379 }
1380
1381 /*
1382  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1383  * we don't create bios that span stripes or chunks
1384  */
1385 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1386                          size_t size, struct bio *bio,
1387                          unsigned long bio_flags)
1388 {
1389         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1390         struct btrfs_mapping_tree *map_tree;
1391         u64 logical = (u64)bio->bi_sector << 9;
1392         u64 length = 0;
1393         u64 map_length;
1394         int ret;
1395
1396         if (bio_flags & EXTENT_BIO_COMPRESSED)
1397                 return 0;
1398
1399         length = bio->bi_size;
1400         map_tree = &root->fs_info->mapping_tree;
1401         map_length = length;
1402         ret = btrfs_map_block(map_tree, READ, logical,
1403                               &map_length, NULL, 0);
1404
1405         if (map_length < length + size)
1406                 return 1;
1407         return ret;
1408 }
1409
1410 /*
1411  * in order to insert checksums into the metadata in large chunks,
1412  * we wait until bio submission time.   All the pages in the bio are
1413  * checksummed and sums are attached onto the ordered extent record.
1414  *
1415  * At IO completion time the cums attached on the ordered extent record
1416  * are inserted into the btree
1417  */
1418 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1419                                     struct bio *bio, int mirror_num,
1420                                     unsigned long bio_flags,
1421                                     u64 bio_offset)
1422 {
1423         struct btrfs_root *root = BTRFS_I(inode)->root;
1424         int ret = 0;
1425
1426         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1427         BUG_ON(ret);
1428         return 0;
1429 }
1430
1431 /*
1432  * in order to insert checksums into the metadata in large chunks,
1433  * we wait until bio submission time.   All the pages in the bio are
1434  * checksummed and sums are attached onto the ordered extent record.
1435  *
1436  * At IO completion time the cums attached on the ordered extent record
1437  * are inserted into the btree
1438  */
1439 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1440                           int mirror_num, unsigned long bio_flags,
1441                           u64 bio_offset)
1442 {
1443         struct btrfs_root *root = BTRFS_I(inode)->root;
1444         return btrfs_map_bio(root, rw, bio, mirror_num, 1);
1445 }
1446
1447 /*
1448  * extent_io.c submission hook. This does the right thing for csum calculation
1449  * on write, or reading the csums from the tree before a read
1450  */
1451 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1452                           int mirror_num, unsigned long bio_flags,
1453                           u64 bio_offset)
1454 {
1455         struct btrfs_root *root = BTRFS_I(inode)->root;
1456         int ret = 0;
1457         int skip_sum;
1458
1459         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1460
1461         if (root == root->fs_info->tree_root)
1462                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 2);
1463         else
1464                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
1465         BUG_ON(ret);
1466
1467         if (!(rw & REQ_WRITE)) {
1468                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1469                         return btrfs_submit_compressed_read(inode, bio,
1470                                                     mirror_num, bio_flags);
1471                 } else if (!skip_sum) {
1472                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1473                         if (ret)
1474                                 return ret;
1475                 }
1476                 goto mapit;
1477         } else if (!skip_sum) {
1478                 /* csum items have already been cloned */
1479                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1480                         goto mapit;
1481                 /* we're doing a write, do the async checksumming */
1482                 return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1483                                    inode, rw, bio, mirror_num,
1484                                    bio_flags, bio_offset,
1485                                    __btrfs_submit_bio_start,
1486                                    __btrfs_submit_bio_done);
1487         }
1488
1489 mapit:
1490         return btrfs_map_bio(root, rw, bio, mirror_num, 0);
1491 }
1492
1493 /*
1494  * given a list of ordered sums record them in the inode.  This happens
1495  * at IO completion time based on sums calculated at bio submission time.
1496  */
1497 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1498                              struct inode *inode, u64 file_offset,
1499                              struct list_head *list)
1500 {
1501         struct btrfs_ordered_sum *sum;
1502
1503         btrfs_set_trans_block_group(trans, inode);
1504
1505         list_for_each_entry(sum, list, list) {
1506                 btrfs_csum_file_blocks(trans,
1507                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1508         }
1509         return 0;
1510 }
1511
1512 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1513                               struct extent_state **cached_state)
1514 {
1515         if ((end & (PAGE_CACHE_SIZE - 1)) == 0)
1516                 WARN_ON(1);
1517         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1518                                    cached_state, GFP_NOFS);
1519 }
1520
1521 /* see btrfs_writepage_start_hook for details on why this is required */
1522 struct btrfs_writepage_fixup {
1523         struct page *page;
1524         struct btrfs_work work;
1525 };
1526
1527 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1528 {
1529         struct btrfs_writepage_fixup *fixup;
1530         struct btrfs_ordered_extent *ordered;
1531         struct extent_state *cached_state = NULL;
1532         struct page *page;
1533         struct inode *inode;
1534         u64 page_start;
1535         u64 page_end;
1536
1537         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1538         page = fixup->page;
1539 again:
1540         lock_page(page);
1541         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1542                 ClearPageChecked(page);
1543                 goto out_page;
1544         }
1545
1546         inode = page->mapping->host;
1547         page_start = page_offset(page);
1548         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1549
1550         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1551                          &cached_state, GFP_NOFS);
1552
1553         /* already ordered? We're done */
1554         if (PagePrivate2(page))
1555                 goto out;
1556
1557         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1558         if (ordered) {
1559                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1560                                      page_end, &cached_state, GFP_NOFS);
1561                 unlock_page(page);
1562                 btrfs_start_ordered_extent(inode, ordered, 1);
1563                 goto again;
1564         }
1565
1566         BUG();
1567         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
1568         ClearPageChecked(page);
1569 out:
1570         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1571                              &cached_state, GFP_NOFS);
1572 out_page:
1573         unlock_page(page);
1574         page_cache_release(page);
1575         kfree(fixup);
1576 }
1577
1578 /*
1579  * There are a few paths in the higher layers of the kernel that directly
1580  * set the page dirty bit without asking the filesystem if it is a
1581  * good idea.  This causes problems because we want to make sure COW
1582  * properly happens and the data=ordered rules are followed.
1583  *
1584  * In our case any range that doesn't have the ORDERED bit set
1585  * hasn't been properly setup for IO.  We kick off an async process
1586  * to fix it up.  The async helper will wait for ordered extents, set
1587  * the delalloc bit and make it safe to write the page.
1588  */
1589 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1590 {
1591         struct inode *inode = page->mapping->host;
1592         struct btrfs_writepage_fixup *fixup;
1593         struct btrfs_root *root = BTRFS_I(inode)->root;
1594
1595         /* this page is properly in the ordered list */
1596         if (TestClearPagePrivate2(page))
1597                 return 0;
1598
1599         if (PageChecked(page))
1600                 return -EAGAIN;
1601
1602         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1603         if (!fixup)
1604                 return -EAGAIN;
1605
1606         SetPageChecked(page);
1607         page_cache_get(page);
1608         fixup->work.func = btrfs_writepage_fixup_worker;
1609         fixup->page = page;
1610         btrfs_queue_worker(&root->fs_info->fixup_workers, &fixup->work);
1611         return -EAGAIN;
1612 }
1613
1614 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1615                                        struct inode *inode, u64 file_pos,
1616                                        u64 disk_bytenr, u64 disk_num_bytes,
1617                                        u64 num_bytes, u64 ram_bytes,
1618                                        u8 compression, u8 encryption,
1619                                        u16 other_encoding, int extent_type)
1620 {
1621         struct btrfs_root *root = BTRFS_I(inode)->root;
1622         struct btrfs_file_extent_item *fi;
1623         struct btrfs_path *path;
1624         struct extent_buffer *leaf;
1625         struct btrfs_key ins;
1626         u64 hint;
1627         int ret;
1628
1629         path = btrfs_alloc_path();
1630         BUG_ON(!path);
1631
1632         path->leave_spinning = 1;
1633
1634         /*
1635          * we may be replacing one extent in the tree with another.
1636          * The new extent is pinned in the extent map, and we don't want
1637          * to drop it from the cache until it is completely in the btree.
1638          *
1639          * So, tell btrfs_drop_extents to leave this extent in the cache.
1640          * the caller is expected to unpin it and allow it to be merged
1641          * with the others.
1642          */
1643         ret = btrfs_drop_extents(trans, inode, file_pos, file_pos + num_bytes,
1644                                  &hint, 0);
1645         BUG_ON(ret);
1646
1647         ins.objectid = inode->i_ino;
1648         ins.offset = file_pos;
1649         ins.type = BTRFS_EXTENT_DATA_KEY;
1650         ret = btrfs_insert_empty_item(trans, root, path, &ins, sizeof(*fi));
1651         BUG_ON(ret);
1652         leaf = path->nodes[0];
1653         fi = btrfs_item_ptr(leaf, path->slots[0],
1654                             struct btrfs_file_extent_item);
1655         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1656         btrfs_set_file_extent_type(leaf, fi, extent_type);
1657         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
1658         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
1659         btrfs_set_file_extent_offset(leaf, fi, 0);
1660         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1661         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
1662         btrfs_set_file_extent_compression(leaf, fi, compression);
1663         btrfs_set_file_extent_encryption(leaf, fi, encryption);
1664         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
1665
1666         btrfs_unlock_up_safe(path, 1);
1667         btrfs_set_lock_blocking(leaf);
1668
1669         btrfs_mark_buffer_dirty(leaf);
1670
1671         inode_add_bytes(inode, num_bytes);
1672
1673         ins.objectid = disk_bytenr;
1674         ins.offset = disk_num_bytes;
1675         ins.type = BTRFS_EXTENT_ITEM_KEY;
1676         ret = btrfs_alloc_reserved_file_extent(trans, root,
1677                                         root->root_key.objectid,
1678                                         inode->i_ino, file_pos, &ins);
1679         BUG_ON(ret);
1680         btrfs_free_path(path);
1681
1682         return 0;
1683 }
1684
1685 /*
1686  * helper function for btrfs_finish_ordered_io, this
1687  * just reads in some of the csum leaves to prime them into ram
1688  * before we start the transaction.  It limits the amount of btree
1689  * reads required while inside the transaction.
1690  */
1691 /* as ordered data IO finishes, this gets called so we can finish
1692  * an ordered extent if the range of bytes in the file it covers are
1693  * fully written.
1694  */
1695 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
1696 {
1697         struct btrfs_root *root = BTRFS_I(inode)->root;
1698         struct btrfs_trans_handle *trans = NULL;
1699         struct btrfs_ordered_extent *ordered_extent = NULL;
1700         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1701         struct extent_state *cached_state = NULL;
1702         int compress_type = 0;
1703         int ret;
1704         bool nolock = false;
1705
1706         ret = btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
1707                                              end - start + 1);
1708         if (!ret)
1709                 return 0;
1710         BUG_ON(!ordered_extent);
1711
1712         nolock = (root == root->fs_info->tree_root);
1713
1714         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
1715                 BUG_ON(!list_empty(&ordered_extent->list));
1716                 ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
1717                 if (!ret) {
1718                         if (nolock)
1719                                 trans = btrfs_join_transaction_nolock(root, 1);
1720                         else
1721                                 trans = btrfs_join_transaction(root, 1);
1722                         BUG_ON(IS_ERR(trans));
1723                         btrfs_set_trans_block_group(trans, inode);
1724                         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1725                         ret = btrfs_update_inode(trans, root, inode);
1726                         BUG_ON(ret);
1727                 }
1728                 goto out;
1729         }
1730
1731         lock_extent_bits(io_tree, ordered_extent->file_offset,
1732                          ordered_extent->file_offset + ordered_extent->len - 1,
1733                          0, &cached_state, GFP_NOFS);
1734
1735         if (nolock)
1736                 trans = btrfs_join_transaction_nolock(root, 1);
1737         else
1738                 trans = btrfs_join_transaction(root, 1);
1739         BUG_ON(IS_ERR(trans));
1740         btrfs_set_trans_block_group(trans, inode);
1741         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1742
1743         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
1744                 compress_type = ordered_extent->compress_type;
1745         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
1746                 BUG_ON(compress_type);
1747                 ret = btrfs_mark_extent_written(trans, inode,
1748                                                 ordered_extent->file_offset,
1749                                                 ordered_extent->file_offset +
1750                                                 ordered_extent->len);
1751                 BUG_ON(ret);
1752         } else {
1753                 BUG_ON(root == root->fs_info->tree_root);
1754                 ret = insert_reserved_file_extent(trans, inode,
1755                                                 ordered_extent->file_offset,
1756                                                 ordered_extent->start,
1757                                                 ordered_extent->disk_len,
1758                                                 ordered_extent->len,
1759                                                 ordered_extent->len,
1760                                                 compress_type, 0, 0,
1761                                                 BTRFS_FILE_EXTENT_REG);
1762                 unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
1763                                    ordered_extent->file_offset,
1764                                    ordered_extent->len);
1765                 BUG_ON(ret);
1766         }
1767         unlock_extent_cached(io_tree, ordered_extent->file_offset,
1768                              ordered_extent->file_offset +
1769                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
1770
1771         add_pending_csums(trans, inode, ordered_extent->file_offset,
1772                           &ordered_extent->list);
1773
1774         ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
1775         if (!ret) {
1776                 ret = btrfs_update_inode(trans, root, inode);
1777                 BUG_ON(ret);
1778         }
1779         ret = 0;
1780 out:
1781         if (nolock) {
1782                 if (trans)
1783                         btrfs_end_transaction_nolock(trans, root);
1784         } else {
1785                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
1786                 if (trans)
1787                         btrfs_end_transaction(trans, root);
1788         }
1789
1790         /* once for us */
1791         btrfs_put_ordered_extent(ordered_extent);
1792         /* once for the tree */
1793         btrfs_put_ordered_extent(ordered_extent);
1794
1795         return 0;
1796 }
1797
1798 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
1799                                 struct extent_state *state, int uptodate)
1800 {
1801         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
1802
1803         ClearPagePrivate2(page);
1804         return btrfs_finish_ordered_io(page->mapping->host, start, end);
1805 }
1806
1807 /*
1808  * When IO fails, either with EIO or csum verification fails, we
1809  * try other mirrors that might have a good copy of the data.  This
1810  * io_failure_record is used to record state as we go through all the
1811  * mirrors.  If another mirror has good data, the page is set up to date
1812  * and things continue.  If a good mirror can't be found, the original
1813  * bio end_io callback is called to indicate things have failed.
1814  */
1815 struct io_failure_record {
1816         struct page *page;
1817         u64 start;
1818         u64 len;
1819         u64 logical;
1820         unsigned long bio_flags;
1821         int last_mirror;
1822 };
1823
1824 static int btrfs_io_failed_hook(struct bio *failed_bio,
1825                          struct page *page, u64 start, u64 end,
1826                          struct extent_state *state)
1827 {
1828         struct io_failure_record *failrec = NULL;
1829         u64 private;
1830         struct extent_map *em;
1831         struct inode *inode = page->mapping->host;
1832         struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
1833         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
1834         struct bio *bio;
1835         int num_copies;
1836         int ret;
1837         int rw;
1838         u64 logical;
1839
1840         ret = get_state_private(failure_tree, start, &private);
1841         if (ret) {
1842                 failrec = kmalloc(sizeof(*failrec), GFP_NOFS);
1843                 if (!failrec)
1844                         return -ENOMEM;
1845                 failrec->start = start;
1846                 failrec->len = end - start + 1;
1847                 failrec->last_mirror = 0;
1848                 failrec->bio_flags = 0;
1849
1850                 read_lock(&em_tree->lock);
1851                 em = lookup_extent_mapping(em_tree, start, failrec->len);
1852                 if (em->start > start || em->start + em->len < start) {
1853                         free_extent_map(em);
1854                         em = NULL;
1855                 }
1856                 read_unlock(&em_tree->lock);
1857
1858                 if (!em || IS_ERR(em)) {
1859                         kfree(failrec);
1860                         return -EIO;
1861                 }
1862                 logical = start - em->start;
1863                 logical = em->block_start + logical;
1864                 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
1865                         logical = em->block_start;
1866                         failrec->bio_flags = EXTENT_BIO_COMPRESSED;
1867                         extent_set_compress_type(&failrec->bio_flags,
1868                                                  em->compress_type);
1869                 }
1870                 failrec->logical = logical;
1871                 free_extent_map(em);
1872                 set_extent_bits(failure_tree, start, end, EXTENT_LOCKED |
1873                                 EXTENT_DIRTY, GFP_NOFS);
1874                 set_state_private(failure_tree, start,
1875                                  (u64)(unsigned long)failrec);
1876         } else {
1877                 failrec = (struct io_failure_record *)(unsigned long)private;
1878         }
1879         num_copies = btrfs_num_copies(
1880                               &BTRFS_I(inode)->root->fs_info->mapping_tree,
1881                               failrec->logical, failrec->len);
1882         failrec->last_mirror++;
1883         if (!state) {
1884                 spin_lock(&BTRFS_I(inode)->io_tree.lock);
1885                 state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
1886                                                     failrec->start,
1887                                                     EXTENT_LOCKED);
1888                 if (state && state->start != failrec->start)
1889                         state = NULL;
1890                 spin_unlock(&BTRFS_I(inode)->io_tree.lock);
1891         }
1892         if (!state || failrec->last_mirror > num_copies) {
1893                 set_state_private(failure_tree, failrec->start, 0);
1894                 clear_extent_bits(failure_tree, failrec->start,
1895                                   failrec->start + failrec->len - 1,
1896                                   EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
1897                 kfree(failrec);
1898                 return -EIO;
1899         }
1900         bio = bio_alloc(GFP_NOFS, 1);
1901         bio->bi_private = state;
1902         bio->bi_end_io = failed_bio->bi_end_io;
1903         bio->bi_sector = failrec->logical >> 9;
1904         bio->bi_bdev = failed_bio->bi_bdev;
1905         bio->bi_size = 0;
1906
1907         bio_add_page(bio, page, failrec->len, start - page_offset(page));
1908         if (failed_bio->bi_rw & REQ_WRITE)
1909                 rw = WRITE;
1910         else
1911                 rw = READ;
1912
1913         ret = BTRFS_I(inode)->io_tree.ops->submit_bio_hook(inode, rw, bio,
1914                                                       failrec->last_mirror,
1915                                                       failrec->bio_flags, 0);
1916         return ret;
1917 }
1918
1919 /*
1920  * each time an IO finishes, we do a fast check in the IO failure tree
1921  * to see if we need to process or clean up an io_failure_record
1922  */
1923 static int btrfs_clean_io_failures(struct inode *inode, u64 start)
1924 {
1925         u64 private;
1926         u64 private_failure;
1927         struct io_failure_record *failure;
1928         int ret;
1929
1930         private = 0;
1931         if (count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
1932                              (u64)-1, 1, EXTENT_DIRTY, 0)) {
1933                 ret = get_state_private(&BTRFS_I(inode)->io_failure_tree,
1934                                         start, &private_failure);
1935                 if (ret == 0) {
1936                         failure = (struct io_failure_record *)(unsigned long)
1937                                    private_failure;
1938                         set_state_private(&BTRFS_I(inode)->io_failure_tree,
1939                                           failure->start, 0);
1940                         clear_extent_bits(&BTRFS_I(inode)->io_failure_tree,
1941                                           failure->start,
1942                                           failure->start + failure->len - 1,
1943                                           EXTENT_DIRTY | EXTENT_LOCKED,
1944                                           GFP_NOFS);
1945                         kfree(failure);
1946                 }
1947         }
1948         return 0;
1949 }
1950
1951 /*
1952  * when reads are done, we need to check csums to verify the data is correct
1953  * if there's a match, we allow the bio to finish.  If not, we go through
1954  * the io_failure_record routines to find good copies
1955  */
1956 static int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,
1957                                struct extent_state *state)
1958 {
1959         size_t offset = start - ((u64)page->index << PAGE_CACHE_SHIFT);
1960         struct inode *inode = page->mapping->host;
1961         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1962         char *kaddr;
1963         u64 private = ~(u32)0;
1964         int ret;
1965         struct btrfs_root *root = BTRFS_I(inode)->root;
1966         u32 csum = ~(u32)0;
1967
1968         if (PageChecked(page)) {
1969                 ClearPageChecked(page);
1970                 goto good;
1971         }
1972
1973         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
1974                 return 0;
1975
1976         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
1977             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
1978                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
1979                                   GFP_NOFS);
1980                 return 0;
1981         }
1982
1983         if (state && state->start == start) {
1984                 private = state->private;
1985                 ret = 0;
1986         } else {
1987                 ret = get_state_private(io_tree, start, &private);
1988         }
1989         kaddr = kmap_atomic(page, KM_USER0);
1990         if (ret)
1991                 goto zeroit;
1992
1993         csum = btrfs_csum_data(root, kaddr + offset, csum,  end - start + 1);
1994         btrfs_csum_final(csum, (char *)&csum);
1995         if (csum != private)
1996                 goto zeroit;
1997
1998         kunmap_atomic(kaddr, KM_USER0);
1999 good:
2000         /* if the io failure tree for this inode is non-empty,
2001          * check to see if we've recovered from a failed IO
2002          */
2003         btrfs_clean_io_failures(inode, start);
2004         return 0;
2005
2006 zeroit:
2007         if (printk_ratelimit()) {
2008                 printk(KERN_INFO "btrfs csum failed ino %lu off %llu csum %u "
2009                        "private %llu\n", page->mapping->host->i_ino,
2010                        (unsigned long long)start, csum,
2011                        (unsigned long long)private);
2012         }
2013         memset(kaddr + offset, 1, end - start + 1);
2014         flush_dcache_page(page);
2015         kunmap_atomic(kaddr, KM_USER0);
2016         if (private == 0)
2017                 return 0;
2018         return -EIO;
2019 }
2020
2021 struct delayed_iput {
2022         struct list_head list;
2023         struct inode *inode;
2024 };
2025
2026 void btrfs_add_delayed_iput(struct inode *inode)
2027 {
2028         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2029         struct delayed_iput *delayed;
2030
2031         if (atomic_add_unless(&inode->i_count, -1, 1))
2032                 return;
2033
2034         delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
2035         delayed->inode = inode;
2036
2037         spin_lock(&fs_info->delayed_iput_lock);
2038         list_add_tail(&delayed->list, &fs_info->delayed_iputs);
2039         spin_unlock(&fs_info->delayed_iput_lock);
2040 }
2041
2042 void btrfs_run_delayed_iputs(struct btrfs_root *root)
2043 {
2044         LIST_HEAD(list);
2045         struct btrfs_fs_info *fs_info = root->fs_info;
2046         struct delayed_iput *delayed;
2047         int empty;
2048
2049         spin_lock(&fs_info->delayed_iput_lock);
2050         empty = list_empty(&fs_info->delayed_iputs);
2051         spin_unlock(&fs_info->delayed_iput_lock);
2052         if (empty)
2053                 return;
2054
2055         down_read(&root->fs_info->cleanup_work_sem);
2056         spin_lock(&fs_info->delayed_iput_lock);
2057         list_splice_init(&fs_info->delayed_iputs, &list);
2058         spin_unlock(&fs_info->delayed_iput_lock);
2059
2060         while (!list_empty(&list)) {
2061                 delayed = list_entry(list.next, struct delayed_iput, list);
2062                 list_del(&delayed->list);
2063                 iput(delayed->inode);
2064                 kfree(delayed);
2065         }
2066         up_read(&root->fs_info->cleanup_work_sem);
2067 }
2068
2069 /*
2070  * calculate extra metadata reservation when snapshotting a subvolume
2071  * contains orphan files.
2072  */
2073 void btrfs_orphan_pre_snapshot(struct btrfs_trans_handle *trans,
2074                                 struct btrfs_pending_snapshot *pending,
2075                                 u64 *bytes_to_reserve)
2076 {
2077         struct btrfs_root *root;
2078         struct btrfs_block_rsv *block_rsv;
2079         u64 num_bytes;
2080         int index;
2081
2082         root = pending->root;
2083         if (!root->orphan_block_rsv || list_empty(&root->orphan_list))
2084                 return;
2085
2086         block_rsv = root->orphan_block_rsv;
2087
2088         /* orphan block reservation for the snapshot */
2089         num_bytes = block_rsv->size;
2090
2091         /*
2092          * after the snapshot is created, COWing tree blocks may use more
2093          * space than it frees. So we should make sure there is enough
2094          * reserved space.
2095          */
2096         index = trans->transid & 0x1;
2097         if (block_rsv->reserved + block_rsv->freed[index] < block_rsv->size) {
2098                 num_bytes += block_rsv->size -
2099                              (block_rsv->reserved + block_rsv->freed[index]);
2100         }
2101
2102         *bytes_to_reserve += num_bytes;
2103 }
2104
2105 void btrfs_orphan_post_snapshot(struct btrfs_trans_handle *trans,
2106                                 struct btrfs_pending_snapshot *pending)
2107 {
2108         struct btrfs_root *root = pending->root;
2109         struct btrfs_root *snap = pending->snap;
2110         struct btrfs_block_rsv *block_rsv;
2111         u64 num_bytes;
2112         int index;
2113         int ret;
2114
2115         if (!root->orphan_block_rsv || list_empty(&root->orphan_list))
2116                 return;
2117
2118         /* refill source subvolume's orphan block reservation */
2119         block_rsv = root->orphan_block_rsv;
2120         index = trans->transid & 0x1;
2121         if (block_rsv->reserved + block_rsv->freed[index] < block_rsv->size) {
2122                 num_bytes = block_rsv->size -
2123                             (block_rsv->reserved + block_rsv->freed[index]);
2124                 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
2125                                               root->orphan_block_rsv,
2126                                               num_bytes);
2127                 BUG_ON(ret);
2128         }
2129
2130         /* setup orphan block reservation for the snapshot */
2131         block_rsv = btrfs_alloc_block_rsv(snap);
2132         BUG_ON(!block_rsv);
2133
2134         btrfs_add_durable_block_rsv(root->fs_info, block_rsv);
2135         snap->orphan_block_rsv = block_rsv;
2136
2137         num_bytes = root->orphan_block_rsv->size;
2138         ret = btrfs_block_rsv_migrate(&pending->block_rsv,
2139                                       block_rsv, num_bytes);
2140         BUG_ON(ret);
2141
2142 #if 0
2143         /* insert orphan item for the snapshot */
2144         WARN_ON(!root->orphan_item_inserted);
2145         ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
2146                                        snap->root_key.objectid);
2147         BUG_ON(ret);
2148         snap->orphan_item_inserted = 1;
2149 #endif
2150 }
2151
2152 enum btrfs_orphan_cleanup_state {
2153         ORPHAN_CLEANUP_STARTED  = 1,
2154         ORPHAN_CLEANUP_DONE     = 2,
2155 };
2156
2157 /*
2158  * This is called in transaction commmit time. If there are no orphan
2159  * files in the subvolume, it removes orphan item and frees block_rsv
2160  * structure.
2161  */
2162 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
2163                               struct btrfs_root *root)
2164 {
2165         int ret;
2166
2167         if (!list_empty(&root->orphan_list) ||
2168             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
2169                 return;
2170
2171         if (root->orphan_item_inserted &&
2172             btrfs_root_refs(&root->root_item) > 0) {
2173                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
2174                                             root->root_key.objectid);
2175                 BUG_ON(ret);
2176                 root->orphan_item_inserted = 0;
2177         }
2178
2179         if (root->orphan_block_rsv) {
2180                 WARN_ON(root->orphan_block_rsv->size > 0);
2181                 btrfs_free_block_rsv(root, root->orphan_block_rsv);
2182                 root->orphan_block_rsv = NULL;
2183         }
2184 }
2185
2186 /*
2187  * This creates an orphan entry for the given inode in case something goes
2188  * wrong in the middle of an unlink/truncate.
2189  *
2190  * NOTE: caller of this function should reserve 5 units of metadata for
2191  *       this function.
2192  */
2193 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
2194 {
2195         struct btrfs_root *root = BTRFS_I(inode)->root;
2196         struct btrfs_block_rsv *block_rsv = NULL;
2197         int reserve = 0;
2198         int insert = 0;
2199         int ret;
2200
2201         if (!root->orphan_block_rsv) {
2202                 block_rsv = btrfs_alloc_block_rsv(root);
2203                 BUG_ON(!block_rsv);
2204         }
2205
2206         spin_lock(&root->orphan_lock);
2207         if (!root->orphan_block_rsv) {
2208                 root->orphan_block_rsv = block_rsv;
2209         } else if (block_rsv) {
2210                 btrfs_free_block_rsv(root, block_rsv);
2211                 block_rsv = NULL;
2212         }
2213
2214         if (list_empty(&BTRFS_I(inode)->i_orphan)) {
2215                 list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
2216 #if 0
2217                 /*
2218                  * For proper ENOSPC handling, we should do orphan
2219                  * cleanup when mounting. But this introduces backward
2220                  * compatibility issue.
2221                  */
2222                 if (!xchg(&root->orphan_item_inserted, 1))
2223                         insert = 2;
2224                 else
2225                         insert = 1;
2226 #endif
2227                 insert = 1;
2228         }
2229
2230         if (!BTRFS_I(inode)->orphan_meta_reserved) {
2231                 BTRFS_I(inode)->orphan_meta_reserved = 1;
2232                 reserve = 1;
2233         }
2234         spin_unlock(&root->orphan_lock);
2235
2236         if (block_rsv)
2237                 btrfs_add_durable_block_rsv(root->fs_info, block_rsv);
2238
2239         /* grab metadata reservation from transaction handle */
2240         if (reserve) {
2241                 ret = btrfs_orphan_reserve_metadata(trans, inode);
2242                 BUG_ON(ret);
2243         }
2244
2245         /* insert an orphan item to track this unlinked/truncated file */
2246         if (insert >= 1) {
2247                 ret = btrfs_insert_orphan_item(trans, root, inode->i_ino);
2248                 BUG_ON(ret);
2249         }
2250
2251         /* insert an orphan item to track subvolume contains orphan files */
2252         if (insert >= 2) {
2253                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
2254                                                root->root_key.objectid);
2255                 BUG_ON(ret);
2256         }
2257         return 0;
2258 }
2259
2260 /*
2261  * We have done the truncate/delete so we can go ahead and remove the orphan
2262  * item for this particular inode.
2263  */
2264 int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode)
2265 {
2266         struct btrfs_root *root = BTRFS_I(inode)->root;
2267         int delete_item = 0;
2268         int release_rsv = 0;
2269         int ret = 0;
2270
2271         spin_lock(&root->orphan_lock);
2272         if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
2273                 list_del_init(&BTRFS_I(inode)->i_orphan);
2274                 delete_item = 1;
2275         }
2276
2277         if (BTRFS_I(inode)->orphan_meta_reserved) {
2278                 BTRFS_I(inode)->orphan_meta_reserved = 0;
2279                 release_rsv = 1;
2280         }
2281         spin_unlock(&root->orphan_lock);
2282
2283         if (trans && delete_item) {
2284                 ret = btrfs_del_orphan_item(trans, root, inode->i_ino);
2285                 BUG_ON(ret);
2286         }
2287
2288         if (release_rsv)
2289                 btrfs_orphan_release_metadata(inode);
2290
2291         return 0;
2292 }
2293
2294 /*
2295  * this cleans up any orphans that may be left on the list from the last use
2296  * of this root.
2297  */
2298 int btrfs_orphan_cleanup(struct btrfs_root *root)
2299 {
2300         struct btrfs_path *path;
2301         struct extent_buffer *leaf;
2302         struct btrfs_key key, found_key;
2303         struct btrfs_trans_handle *trans;
2304         struct inode *inode;
2305         int ret = 0, nr_unlink = 0, nr_truncate = 0;
2306
2307         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
2308                 return 0;
2309
2310         path = btrfs_alloc_path();
2311         if (!path) {
2312                 ret = -ENOMEM;
2313                 goto out;
2314         }
2315         path->reada = -1;
2316
2317         key.objectid = BTRFS_ORPHAN_OBJECTID;
2318         btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
2319         key.offset = (u64)-1;
2320
2321         while (1) {
2322                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2323                 if (ret < 0)
2324                         goto out;
2325
2326                 /*
2327                  * if ret == 0 means we found what we were searching for, which
2328                  * is weird, but possible, so only screw with path if we didn't
2329                  * find the key and see if we have stuff that matches
2330                  */
2331                 if (ret > 0) {
2332                         ret = 0;
2333                         if (path->slots[0] == 0)
2334                                 break;
2335                         path->slots[0]--;
2336                 }
2337
2338                 /* pull out the item */
2339                 leaf = path->nodes[0];
2340                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2341
2342                 /* make sure the item matches what we want */
2343                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
2344                         break;
2345                 if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
2346                         break;
2347
2348                 /* release the path since we're done with it */
2349                 btrfs_release_path(root, path);
2350
2351                 /*
2352                  * this is where we are basically btrfs_lookup, without the
2353                  * crossing root thing.  we store the inode number in the
2354                  * offset of the orphan item.
2355                  */
2356                 found_key.objectid = found_key.offset;
2357                 found_key.type = BTRFS_INODE_ITEM_KEY;
2358                 found_key.offset = 0;
2359                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
2360                 if (IS_ERR(inode)) {
2361                         ret = PTR_ERR(inode);
2362                         goto out;
2363                 }
2364
2365                 /*
2366                  * add this inode to the orphan list so btrfs_orphan_del does
2367                  * the proper thing when we hit it
2368                  */
2369                 spin_lock(&root->orphan_lock);
2370                 list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
2371                 spin_unlock(&root->orphan_lock);
2372
2373                 /*
2374                  * if this is a bad inode, means we actually succeeded in
2375                  * removing the inode, but not the orphan record, which means
2376                  * we need to manually delete the orphan since iput will just
2377                  * do a destroy_inode
2378                  */
2379                 if (is_bad_inode(inode)) {
2380                         trans = btrfs_start_transaction(root, 0);
2381                         if (IS_ERR(trans)) {
2382                                 ret = PTR_ERR(trans);
2383                                 goto out;
2384                         }
2385                         btrfs_orphan_del(trans, inode);
2386                         btrfs_end_transaction(trans, root);
2387                         iput(inode);
2388                         continue;
2389                 }
2390
2391                 /* if we have links, this was a truncate, lets do that */
2392                 if (inode->i_nlink) {
2393                         if (!S_ISREG(inode->i_mode)) {
2394                                 WARN_ON(1);
2395                                 iput(inode);
2396                                 continue;
2397                         }
2398                         nr_truncate++;
2399                         ret = btrfs_truncate(inode);
2400                 } else {
2401                         nr_unlink++;
2402                 }
2403
2404                 /* this will do delete_inode and everything for us */
2405                 iput(inode);
2406                 if (ret)
2407                         goto out;
2408         }
2409         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
2410
2411         if (root->orphan_block_rsv)
2412                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
2413                                         (u64)-1);
2414
2415         if (root->orphan_block_rsv || root->orphan_item_inserted) {
2416                 trans = btrfs_join_transaction(root, 1);
2417                 if (!IS_ERR(trans))
2418                         btrfs_end_transaction(trans, root);
2419         }
2420
2421         if (nr_unlink)
2422                 printk(KERN_INFO "btrfs: unlinked %d orphans\n", nr_unlink);
2423         if (nr_truncate)
2424                 printk(KERN_INFO "btrfs: truncated %d orphans\n", nr_truncate);
2425
2426 out:
2427         if (ret)
2428                 printk(KERN_CRIT "btrfs: could not do orphan cleanup %d\n", ret);
2429         btrfs_free_path(path);
2430         return ret;
2431 }
2432
2433 /*
2434  * very simple check to peek ahead in the leaf looking for xattrs.  If we
2435  * don't find any xattrs, we know there can't be any acls.
2436  *
2437  * slot is the slot the inode is in, objectid is the objectid of the inode
2438  */
2439 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
2440                                           int slot, u64 objectid)
2441 {
2442         u32 nritems = btrfs_header_nritems(leaf);
2443         struct btrfs_key found_key;
2444         int scanned = 0;
2445
2446         slot++;
2447         while (slot < nritems) {
2448                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2449
2450                 /* we found a different objectid, there must not be acls */
2451                 if (found_key.objectid != objectid)
2452                         return 0;
2453
2454                 /* we found an xattr, assume we've got an acl */
2455                 if (found_key.type == BTRFS_XATTR_ITEM_KEY)
2456                         return 1;
2457
2458                 /*
2459                  * we found a key greater than an xattr key, there can't
2460                  * be any acls later on
2461                  */
2462                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
2463                         return 0;
2464
2465                 slot++;
2466                 scanned++;
2467
2468                 /*
2469                  * it goes inode, inode backrefs, xattrs, extents,
2470                  * so if there are a ton of hard links to an inode there can
2471                  * be a lot of backrefs.  Don't waste time searching too hard,
2472                  * this is just an optimization
2473                  */
2474                 if (scanned >= 8)
2475                         break;
2476         }
2477         /* we hit the end of the leaf before we found an xattr or
2478          * something larger than an xattr.  We have to assume the inode
2479          * has acls
2480          */
2481         return 1;
2482 }
2483
2484 /*
2485  * read an inode from the btree into the in-memory inode
2486  */
2487 static void btrfs_read_locked_inode(struct inode *inode)
2488 {
2489         struct btrfs_path *path;
2490         struct extent_buffer *leaf;
2491         struct btrfs_inode_item *inode_item;
2492         struct btrfs_timespec *tspec;
2493         struct btrfs_root *root = BTRFS_I(inode)->root;
2494         struct btrfs_key location;
2495         int maybe_acls;
2496         u64 alloc_group_block;
2497         u32 rdev;
2498         int ret;
2499
2500         path = btrfs_alloc_path();
2501         BUG_ON(!path);
2502         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
2503
2504         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
2505         if (ret)
2506                 goto make_bad;
2507
2508         leaf = path->nodes[0];
2509         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2510                                     struct btrfs_inode_item);
2511
2512         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
2513         inode->i_nlink = btrfs_inode_nlink(leaf, inode_item);
2514         inode->i_uid = btrfs_inode_uid(leaf, inode_item);
2515         inode->i_gid = btrfs_inode_gid(leaf, inode_item);
2516         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
2517
2518         tspec = btrfs_inode_atime(inode_item);
2519         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2520         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2521
2522         tspec = btrfs_inode_mtime(inode_item);
2523         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2524         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2525
2526         tspec = btrfs_inode_ctime(inode_item);
2527         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2528         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2529
2530         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
2531         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
2532         BTRFS_I(inode)->sequence = btrfs_inode_sequence(leaf, inode_item);
2533         inode->i_generation = BTRFS_I(inode)->generation;
2534         inode->i_rdev = 0;
2535         rdev = btrfs_inode_rdev(leaf, inode_item);
2536
2537         BTRFS_I(inode)->index_cnt = (u64)-1;
2538         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
2539
2540         alloc_group_block = btrfs_inode_block_group(leaf, inode_item);
2541
2542         /*
2543          * try to precache a NULL acl entry for files that don't have
2544          * any xattrs or acls
2545          */
2546         maybe_acls = acls_after_inode_item(leaf, path->slots[0], inode->i_ino);
2547         if (!maybe_acls)
2548                 cache_no_acl(inode);
2549
2550         BTRFS_I(inode)->block_group = btrfs_find_block_group(root, 0,
2551                                                 alloc_group_block, 0);
2552         btrfs_free_path(path);
2553         inode_item = NULL;
2554
2555         switch (inode->i_mode & S_IFMT) {
2556         case S_IFREG:
2557                 inode->i_mapping->a_ops = &btrfs_aops;
2558                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2559                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
2560                 inode->i_fop = &btrfs_file_operations;
2561                 inode->i_op = &btrfs_file_inode_operations;
2562                 break;
2563         case S_IFDIR:
2564                 inode->i_fop = &btrfs_dir_file_operations;
2565                 if (root == root->fs_info->tree_root)
2566                         inode->i_op = &btrfs_dir_ro_inode_operations;
2567                 else
2568                         inode->i_op = &btrfs_dir_inode_operations;
2569                 break;
2570         case S_IFLNK:
2571                 inode->i_op = &btrfs_symlink_inode_operations;
2572                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
2573                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2574                 break;
2575         default:
2576                 inode->i_op = &btrfs_special_inode_operations;
2577                 init_special_inode(inode, inode->i_mode, rdev);
2578                 break;
2579         }
2580
2581         btrfs_update_iflags(inode);
2582         return;
2583
2584 make_bad:
2585         btrfs_free_path(path);
2586         make_bad_inode(inode);
2587 }
2588
2589 /*
2590  * given a leaf and an inode, copy the inode fields into the leaf
2591  */
2592 static void fill_inode_item(struct btrfs_trans_handle *trans,
2593                             struct extent_buffer *leaf,
2594                             struct btrfs_inode_item *item,
2595                             struct inode *inode)
2596 {
2597         if (!leaf->map_token)
2598                 map_private_extent_buffer(leaf, (unsigned long)item,
2599                                           sizeof(struct btrfs_inode_item),
2600                                           &leaf->map_token, &leaf->kaddr,
2601                                           &leaf->map_start, &leaf->map_len,
2602                                           KM_USER1);
2603
2604         btrfs_set_inode_uid(leaf, item, inode->i_uid);
2605         btrfs_set_inode_gid(leaf, item, inode->i_gid);
2606         btrfs_set_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size);
2607         btrfs_set_inode_mode(leaf, item, inode->i_mode);
2608         btrfs_set_inode_nlink(leaf, item, inode->i_nlink);
2609
2610         btrfs_set_timespec_sec(leaf, btrfs_inode_atime(item),
2611                                inode->i_atime.tv_sec);
2612         btrfs_set_timespec_nsec(leaf, btrfs_inode_atime(item),
2613                                 inode->i_atime.tv_nsec);
2614
2615         btrfs_set_timespec_sec(leaf, btrfs_inode_mtime(item),
2616                                inode->i_mtime.tv_sec);
2617         btrfs_set_timespec_nsec(leaf, btrfs_inode_mtime(item),
2618                                 inode->i_mtime.tv_nsec);
2619
2620         btrfs_set_timespec_sec(leaf, btrfs_inode_ctime(item),
2621                                inode->i_ctime.tv_sec);
2622         btrfs_set_timespec_nsec(leaf, btrfs_inode_ctime(item),
2623                                 inode->i_ctime.tv_nsec);
2624
2625         btrfs_set_inode_nbytes(leaf, item, inode_get_bytes(inode));
2626         btrfs_set_inode_generation(leaf, item, BTRFS_I(inode)->generation);
2627         btrfs_set_inode_sequence(leaf, item, BTRFS_I(inode)->sequence);
2628         btrfs_set_inode_transid(leaf, item, trans->transid);
2629         btrfs_set_inode_rdev(leaf, item, inode->i_rdev);
2630         btrfs_set_inode_flags(leaf, item, BTRFS_I(inode)->flags);
2631         btrfs_set_inode_block_group(leaf, item, BTRFS_I(inode)->block_group);
2632
2633         if (leaf->map_token) {
2634                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2635                 leaf->map_token = NULL;
2636         }
2637 }
2638
2639 /*
2640  * copy everything in the in-memory inode into the btree.
2641  */
2642 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
2643                                 struct btrfs_root *root, struct inode *inode)
2644 {
2645         struct btrfs_inode_item *inode_item;
2646         struct btrfs_path *path;
2647         struct extent_buffer *leaf;
2648         int ret;
2649
2650         path = btrfs_alloc_path();
2651         BUG_ON(!path);
2652         path->leave_spinning = 1;
2653         ret = btrfs_lookup_inode(trans, root, path,
2654                                  &BTRFS_I(inode)->location, 1);
2655         if (ret) {
2656                 if (ret > 0)
2657                         ret = -ENOENT;
2658                 goto failed;
2659         }
2660
2661         btrfs_unlock_up_safe(path, 1);
2662         leaf = path->nodes[0];
2663         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2664                                   struct btrfs_inode_item);
2665
2666         fill_inode_item(trans, leaf, inode_item, inode);
2667         btrfs_mark_buffer_dirty(leaf);
2668         btrfs_set_inode_last_trans(trans, inode);
2669         ret = 0;
2670 failed:
2671         btrfs_free_path(path);
2672         return ret;
2673 }
2674
2675
2676 /*
2677  * unlink helper that gets used here in inode.c and in the tree logging
2678  * recovery code.  It remove a link in a directory with a given name, and
2679  * also drops the back refs in the inode to the directory
2680  */
2681 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2682                                 struct btrfs_root *root,
2683                                 struct inode *dir, struct inode *inode,
2684                                 const char *name, int name_len)
2685 {
2686         struct btrfs_path *path;
2687         int ret = 0;
2688         struct extent_buffer *leaf;
2689         struct btrfs_dir_item *di;
2690         struct btrfs_key key;
2691         u64 index;
2692
2693         path = btrfs_alloc_path();
2694         if (!path) {
2695                 ret = -ENOMEM;
2696                 goto out;
2697         }
2698
2699         path->leave_spinning = 1;
2700         di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
2701                                     name, name_len, -1);
2702         if (IS_ERR(di)) {
2703                 ret = PTR_ERR(di);
2704                 goto err;
2705         }
2706         if (!di) {
2707                 ret = -ENOENT;
2708                 goto err;
2709         }
2710         leaf = path->nodes[0];
2711         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2712         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2713         if (ret)
2714                 goto err;
2715         btrfs_release_path(root, path);
2716
2717         ret = btrfs_del_inode_ref(trans, root, name, name_len,
2718                                   inode->i_ino,
2719                                   dir->i_ino, &index);
2720         if (ret) {
2721                 printk(KERN_INFO "btrfs failed to delete reference to %.*s, "
2722                        "inode %lu parent %lu\n", name_len, name,
2723                        inode->i_ino, dir->i_ino);
2724                 goto err;
2725         }
2726
2727         di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
2728                                          index, name, name_len, -1);
2729         if (IS_ERR(di)) {
2730                 ret = PTR_ERR(di);
2731                 goto err;
2732         }
2733         if (!di) {
2734                 ret = -ENOENT;
2735                 goto err;
2736         }
2737         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2738         btrfs_release_path(root, path);
2739
2740         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
2741                                          inode, dir->i_ino);
2742         BUG_ON(ret != 0 && ret != -ENOENT);
2743
2744         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
2745                                            dir, index);
2746         if (ret == -ENOENT)
2747                 ret = 0;
2748 err:
2749         btrfs_free_path(path);
2750         if (ret)
2751                 goto out;
2752
2753         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
2754         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
2755         btrfs_update_inode(trans, root, dir);
2756 out:
2757         return ret;
2758 }
2759
2760 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2761                        struct btrfs_root *root,
2762                        struct inode *dir, struct inode *inode,
2763                        const char *name, int name_len)
2764 {
2765         int ret;
2766         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
2767         if (!ret) {
2768                 btrfs_drop_nlink(inode);
2769                 ret = btrfs_update_inode(trans, root, inode);
2770         }
2771         return ret;
2772 }
2773                 
2774
2775 /* helper to check if there is any shared block in the path */
2776 static int check_path_shared(struct btrfs_root *root,
2777                              struct btrfs_path *path)
2778 {
2779         struct extent_buffer *eb;
2780         int level;
2781         u64 refs = 1;
2782
2783         for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2784                 int ret;
2785
2786                 if (!path->nodes[level])
2787                         break;
2788                 eb = path->nodes[level];
2789                 if (!btrfs_block_can_be_shared(root, eb))
2790                         continue;
2791                 ret = btrfs_lookup_extent_info(NULL, root, eb->start, eb->len,
2792                                                &refs, NULL);
2793                 if (refs > 1)
2794                         return 1;
2795         }
2796         return 0;
2797 }
2798
2799 /*
2800  * helper to start transaction for unlink and rmdir.
2801  *
2802  * unlink and rmdir are special in btrfs, they do not always free space.
2803  * so in enospc case, we should make sure they will free space before
2804  * allowing them to use the global metadata reservation.
2805  */
2806 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir,
2807                                                        struct dentry *dentry)
2808 {
2809         struct btrfs_trans_handle *trans;
2810         struct btrfs_root *root = BTRFS_I(dir)->root;
2811         struct btrfs_path *path;
2812         struct btrfs_inode_ref *ref;
2813         struct btrfs_dir_item *di;
2814         struct inode *inode = dentry->d_inode;
2815         u64 index;
2816         int check_link = 1;
2817         int err = -ENOSPC;
2818         int ret;
2819
2820         trans = btrfs_start_transaction(root, 10);
2821         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
2822                 return trans;
2823
2824         if (inode->i_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
2825                 return ERR_PTR(-ENOSPC);
2826
2827         /* check if there is someone else holds reference */
2828         if (S_ISDIR(inode->i_mode) && atomic_read(&inode->i_count) > 1)
2829                 return ERR_PTR(-ENOSPC);
2830
2831         if (atomic_read(&inode->i_count) > 2)
2832                 return ERR_PTR(-ENOSPC);
2833
2834         if (xchg(&root->fs_info->enospc_unlink, 1))
2835                 return ERR_PTR(-ENOSPC);
2836
2837         path = btrfs_alloc_path();
2838         if (!path) {
2839                 root->fs_info->enospc_unlink = 0;
2840                 return ERR_PTR(-ENOMEM);
2841         }
2842
2843         trans = btrfs_start_transaction(root, 0);
2844         if (IS_ERR(trans)) {
2845                 btrfs_free_path(path);
2846                 root->fs_info->enospc_unlink = 0;
2847                 return trans;
2848         }
2849
2850         path->skip_locking = 1;
2851         path->search_commit_root = 1;
2852
2853         ret = btrfs_lookup_inode(trans, root, path,
2854                                 &BTRFS_I(dir)->location, 0);
2855         if (ret < 0) {
2856                 err = ret;
2857                 goto out;
2858         }
2859         if (ret == 0) {
2860                 if (check_path_shared(root, path))
2861                         goto out;
2862         } else {
2863                 check_link = 0;
2864         }
2865         btrfs_release_path(root, path);
2866
2867         ret = btrfs_lookup_inode(trans, root, path,
2868                                 &BTRFS_I(inode)->location, 0);
2869         if (ret < 0) {
2870                 err = ret;
2871                 goto out;
2872         }
2873         if (ret == 0) {
2874                 if (check_path_shared(root, path))
2875                         goto out;
2876         } else {
2877                 check_link = 0;
2878         }
2879         btrfs_release_path(root, path);
2880
2881         if (ret == 0 && S_ISREG(inode->i_mode)) {
2882                 ret = btrfs_lookup_file_extent(trans, root, path,
2883                                                inode->i_ino, (u64)-1, 0);
2884                 if (ret < 0) {
2885                         err = ret;
2886                         goto out;
2887                 }
2888                 BUG_ON(ret == 0);
2889                 if (check_path_shared(root, path))
2890                         goto out;
2891                 btrfs_release_path(root, path);
2892         }
2893
2894         if (!check_link) {
2895                 err = 0;
2896                 goto out;
2897         }
2898
2899         di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
2900                                 dentry->d_name.name, dentry->d_name.len, 0);
2901         if (IS_ERR(di)) {
2902                 err = PTR_ERR(di);
2903                 goto out;
2904         }
2905         if (di) {
2906                 if (check_path_shared(root, path))
2907                         goto out;
2908         } else {
2909                 err = 0;
2910                 goto out;
2911         }
2912         btrfs_release_path(root, path);
2913
2914         ref = btrfs_lookup_inode_ref(trans, root, path,
2915                                 dentry->d_name.name, dentry->d_name.len,
2916                                 inode->i_ino, dir->i_ino, 0);
2917         if (IS_ERR(ref)) {
2918                 err = PTR_ERR(ref);
2919                 goto out;
2920         }
2921         BUG_ON(!ref);
2922         if (check_path_shared(root, path))
2923                 goto out;
2924         index = btrfs_inode_ref_index(path->nodes[0], ref);
2925         btrfs_release_path(root, path);
2926
2927         di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino, index,
2928                                 dentry->d_name.name, dentry->d_name.len, 0);
2929         if (IS_ERR(di)) {
2930                 err = PTR_ERR(di);
2931                 goto out;
2932         }
2933         BUG_ON(ret == -ENOENT);
2934         if (check_path_shared(root, path))
2935                 goto out;
2936
2937         err = 0;
2938 out:
2939         btrfs_free_path(path);
2940         if (err) {
2941                 btrfs_end_transaction(trans, root);
2942                 root->fs_info->enospc_unlink = 0;
2943                 return ERR_PTR(err);
2944         }
2945
2946         trans->block_rsv = &root->fs_info->global_block_rsv;
2947         return trans;
2948 }
2949
2950 static void __unlink_end_trans(struct btrfs_trans_handle *trans,
2951                                struct btrfs_root *root)
2952 {
2953         if (trans->block_rsv == &root->fs_info->global_block_rsv) {
2954                 BUG_ON(!root->fs_info->enospc_unlink);
2955                 root->fs_info->enospc_unlink = 0;
2956         }
2957         btrfs_end_transaction_throttle(trans, root);
2958 }
2959
2960 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
2961 {
2962         struct btrfs_root *root = BTRFS_I(dir)->root;
2963         struct btrfs_trans_handle *trans;
2964         struct inode *inode = dentry->d_inode;
2965         int ret;
2966         unsigned long nr = 0;
2967
2968         trans = __unlink_start_trans(dir, dentry);
2969         if (IS_ERR(trans))
2970                 return PTR_ERR(trans);
2971
2972         btrfs_set_trans_block_group(trans, dir);
2973
2974         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
2975
2976         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
2977                                  dentry->d_name.name, dentry->d_name.len);
2978         BUG_ON(ret);
2979
2980         if (inode->i_nlink == 0) {
2981                 ret = btrfs_orphan_add(trans, inode);
2982                 BUG_ON(ret);
2983         }
2984
2985         nr = trans->blocks_used;
2986         __unlink_end_trans(trans, root);
2987         btrfs_btree_balance_dirty(root, nr);
2988         return ret;
2989 }
2990
2991 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
2992                         struct btrfs_root *root,
2993                         struct inode *dir, u64 objectid,
2994                         const char *name, int name_len)
2995 {
2996         struct btrfs_path *path;
2997         struct extent_buffer *leaf;
2998         struct btrfs_dir_item *di;
2999         struct btrfs_key key;
3000         u64 index;
3001         int ret;
3002
3003         path = btrfs_alloc_path();
3004         if (!path)
3005                 return -ENOMEM;
3006
3007         di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
3008                                    name, name_len, -1);
3009         BUG_ON(!di || IS_ERR(di));
3010
3011         leaf = path->nodes[0];
3012         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3013         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3014         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3015         BUG_ON(ret);
3016         btrfs_release_path(root, path);
3017
3018         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
3019                                  objectid, root->root_key.objectid,
3020                                  dir->i_ino, &index, name, name_len);
3021         if (ret < 0) {
3022                 BUG_ON(ret != -ENOENT);
3023                 di = btrfs_search_dir_index_item(root, path, dir->i_ino,
3024                                                  name, name_len);
3025                 BUG_ON(!di || IS_ERR(di));
3026
3027                 leaf = path->nodes[0];
3028                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3029                 btrfs_release_path(root, path);
3030                 index = key.offset;
3031         }
3032
3033         di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
3034                                          index, name, name_len, -1);
3035         BUG_ON(!di || IS_ERR(di));
3036
3037         leaf = path->nodes[0];
3038         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3039         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3040         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3041         BUG_ON(ret);
3042         btrfs_release_path(root, path);
3043
3044         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3045         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3046         ret = btrfs_update_inode(trans, root, dir);
3047         BUG_ON(ret);
3048
3049         btrfs_free_path(path);
3050         return 0;
3051 }
3052
3053 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
3054 {
3055         struct inode *inode = dentry->d_inode;
3056         int err = 0;
3057         struct btrfs_root *root = BTRFS_I(dir)->root;
3058         struct btrfs_trans_handle *trans;
3059         unsigned long nr = 0;
3060
3061         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE ||
3062             inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
3063                 return -ENOTEMPTY;
3064
3065         dentry_unhash(dentry);
3066
3067         trans = __unlink_start_trans(dir, dentry);
3068         if (IS_ERR(trans))
3069                 return PTR_ERR(trans);
3070
3071         btrfs_set_trans_block_group(trans, dir);
3072
3073         if (unlikely(inode->i_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
3074                 err = btrfs_unlink_subvol(trans, root, dir,
3075                                           BTRFS_I(inode)->location.objectid,
3076                                           dentry->d_name.name,
3077                                           dentry->d_name.len);
3078                 goto out;
3079         }
3080
3081         err = btrfs_orphan_add(trans, inode);
3082         if (err)
3083                 goto out;
3084
3085         /* now the directory is empty */
3086         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3087                                  dentry->d_name.name, dentry->d_name.len);
3088         if (!err)
3089                 btrfs_i_size_write(inode, 0);
3090 out:
3091         nr = trans->blocks_used;
3092         __unlink_end_trans(trans, root);
3093         btrfs_btree_balance_dirty(root, nr);
3094
3095         return err;
3096 }
3097
3098 #if 0
3099 /*
3100  * when truncating bytes in a file, it is possible to avoid reading
3101  * the leaves that contain only checksum items.  This can be the
3102  * majority of the IO required to delete a large file, but it must
3103  * be done carefully.
3104  *
3105  * The keys in the level just above the leaves are checked to make sure
3106  * the lowest key in a given leaf is a csum key, and starts at an offset
3107  * after the new  size.
3108  *
3109  * Then the key for the next leaf is checked to make sure it also has
3110  * a checksum item for the same file.  If it does, we know our target leaf
3111  * contains only checksum items, and it can be safely freed without reading
3112  * it.
3113  *
3114  * This is just an optimization targeted at large files.  It may do
3115  * nothing.  It will return 0 unless things went badly.
3116  */
3117 static noinline int drop_csum_leaves(struct btrfs_trans_handle *trans,
3118                                      struct btrfs_root *root,
3119                                      struct btrfs_path *path,
3120                                      struct inode *inode, u64 new_size)
3121 {
3122         struct btrfs_key key;
3123         int ret;
3124         int nritems;
3125         struct btrfs_key found_key;
3126         struct btrfs_key other_key;
3127         struct btrfs_leaf_ref *ref;
3128         u64 leaf_gen;
3129         u64 leaf_start;
3130
3131         path->lowest_level = 1;
3132         key.objectid = inode->i_ino;
3133         key.type = BTRFS_CSUM_ITEM_KEY;
3134         key.offset = new_size;
3135 again:
3136         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3137         if (ret < 0)
3138                 goto out;
3139
3140         if (path->nodes[1] == NULL) {
3141                 ret = 0;
3142                 goto out;
3143         }
3144         ret = 0;
3145         btrfs_node_key_to_cpu(path->nodes[1], &found_key, path->slots[1]);
3146         nritems = btrfs_header_nritems(path->nodes[1]);
3147
3148         if (!nritems)
3149                 goto out;
3150
3151         if (path->slots[1] >= nritems)
3152                 goto next_node;
3153
3154         /* did we find a key greater than anything we want to delete? */
3155         if (found_key.objectid > inode->i_ino ||
3156            (found_key.objectid == inode->i_ino && found_key.type > key.type))
3157                 goto out;
3158
3159         /* we check the next key in the node to make sure the leave contains
3160          * only checksum items.  This comparison doesn't work if our
3161          * leaf is the last one in the node
3162          */
3163         if (path->slots[1] + 1 >= nritems) {
3164 next_node:
3165                 /* search forward from the last key in the node, this
3166                  * will bring us into the next node in the tree
3167                  */
3168                 btrfs_node_key_to_cpu(path->nodes[1], &found_key, nritems - 1);
3169
3170                 /* unlikely, but we inc below, so check to be safe */
3171                 if (found_key.offset == (u64)-1)
3172                         goto out;
3173
3174                 /* search_forward needs a path with locks held, do the
3175                  * search again for the original key.  It is possible
3176                  * this will race with a balance and return a path that
3177                  * we could modify, but this drop is just an optimization
3178                  * and is allowed to miss some leaves.
3179                  */
3180                 btrfs_release_path(root, path);
3181                 found_key.offset++;
3182
3183                 /* setup a max key for search_forward */
3184                 other_key.offset = (u64)-1;
3185                 other_key.type = key.type;
3186                 other_key.objectid = key.objectid;
3187
3188                 path->keep_locks = 1;
3189                 ret = btrfs_search_forward(root, &found_key, &other_key,
3190                                            path, 0, 0);
3191                 path->keep_locks = 0;
3192                 if (ret || found_key.objectid != key.objectid ||
3193                     found_key.type != key.type) {
3194                         ret = 0;
3195                         goto out;
3196                 }
3197
3198                 key.offset = found_key.offset;
3199                 btrfs_release_path(root, path);
3200                 cond_resched();
3201                 goto again;
3202         }
3203
3204         /* we know there's one more slot after us in the tree,
3205          * read that key so we can verify it is also a checksum item
3206          */
3207         btrfs_node_key_to_cpu(path->nodes[1], &other_key, path->slots[1] + 1);
3208
3209         if (found_key.objectid < inode->i_ino)
3210                 goto next_key;
3211
3212         if (found_key.type != key.type || found_key.offset < new_size)
3213                 goto next_key;
3214
3215         /*
3216          * if the key for the next leaf isn't a csum key from this objectid,
3217          * we can't be sure there aren't good items inside this leaf.
3218          * Bail out
3219          */
3220         if (other_key.objectid != inode->i_ino || other_key.type != key.type)
3221                 goto out;
3222
3223         leaf_start = btrfs_node_blockptr(path->nodes[1], path->slots[1]);
3224         leaf_gen = btrfs_node_ptr_generation(path->nodes[1], path->slots[1]);
3225         /*
3226          * it is safe to delete this leaf, it contains only
3227          * csum items from this inode at an offset >= new_size
3228          */
3229         ret = btrfs_del_leaf(trans, root, path, leaf_start);
3230         BUG_ON(ret);
3231
3232         if (root->ref_cows && leaf_gen < trans->transid) {
3233                 ref = btrfs_alloc_leaf_ref(root, 0);
3234                 if (ref) {
3235                         ref->root_gen = root->root_key.offset;
3236                         ref->bytenr = leaf_start;
3237                         ref->owner = 0;
3238                         ref->generation = leaf_gen;
3239                         ref->nritems = 0;
3240
3241                         btrfs_sort_leaf_ref(ref);
3242
3243                         ret = btrfs_add_leaf_ref(root, ref, 0);
3244                         WARN_ON(ret);
3245                         btrfs_free_leaf_ref(root, ref);
3246                 } else {
3247                         WARN_ON(1);
3248                 }
3249         }
3250 next_key:
3251         btrfs_release_path(root, path);
3252
3253         if (other_key.objectid == inode->i_ino &&
3254             other_key.type == key.type && other_key.offset > key.offset) {
3255                 key.offset = other_key.offset;
3256                 cond_resched();
3257                 goto again;
3258         }
3259         ret = 0;
3260 out:
3261         /* fixup any changes we've made to the path */
3262         path->lowest_level = 0;
3263         path->keep_locks = 0;
3264         btrfs_release_path(root, path);
3265         return ret;
3266 }
3267
3268 #endif
3269
3270 /*
3271  * this can truncate away extent items, csum items and directory items.
3272  * It starts at a high offset and removes keys until it can't find
3273  * any higher than new_size
3274  *
3275  * csum items that cross the new i_size are truncated to the new size
3276  * as well.
3277  *
3278  * min_type is the minimum key type to truncate down to.  If set to 0, this
3279  * will kill all the items on this inode, including the INODE_ITEM_KEY.
3280  */
3281 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
3282                                struct btrfs_root *root,
3283                                struct inode *inode,
3284                                u64 new_size, u32 min_type)
3285 {
3286         struct btrfs_path *path;
3287         struct extent_buffer *leaf;
3288         struct btrfs_file_extent_item *fi;
3289         struct btrfs_key key;
3290         struct btrfs_key found_key;
3291         u64 extent_start = 0;
3292         u64 extent_num_bytes = 0;
3293         u64 extent_offset = 0;
3294         u64 item_end = 0;
3295         u64 mask = root->sectorsize - 1;
3296         u32 found_type = (u8)-1;
3297         int found_extent;
3298         int del_item;
3299         int pending_del_nr = 0;
3300         int pending_del_slot = 0;
3301         int extent_type = -1;
3302         int encoding;
3303         int ret;
3304         int err = 0;
3305
3306         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
3307
3308         if (root->ref_cows || root == root->fs_info->tree_root)
3309                 btrfs_drop_extent_cache(inode, new_size & (~mask), (u64)-1, 0);
3310
3311         path = btrfs_alloc_path();
3312         BUG_ON(!path);
3313         path->reada = -1;
3314
3315         key.objectid = inode->i_ino;
3316         key.offset = (u64)-1;
3317         key.type = (u8)-1;
3318
3319 search_again:
3320         path->leave_spinning = 1;
3321         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3322         if (ret < 0) {
3323                 err = ret;
3324                 goto out;
3325         }
3326
3327         if (ret > 0) {
3328                 /* there are no items in the tree for us to truncate, we're
3329                  * done
3330                  */
3331                 if (path->slots[0] == 0)
3332                         goto out;
3333                 path->slots[0]--;
3334         }
3335
3336         while (1) {
3337                 fi = NULL;
3338                 leaf = path->nodes[0];
3339                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3340                 found_type = btrfs_key_type(&found_key);
3341                 encoding = 0;
3342
3343                 if (found_key.objectid != inode->i_ino)
3344                         break;
3345
3346                 if (found_type < min_type)
3347                         break;
3348
3349                 item_end = found_key.offset;
3350                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
3351                         fi = btrfs_item_ptr(leaf, path->slots[0],
3352                                             struct btrfs_file_extent_item);
3353                         extent_type = btrfs_file_extent_type(leaf, fi);
3354                         encoding = btrfs_file_extent_compression(leaf, fi);
3355                         encoding |= btrfs_file_extent_encryption(leaf, fi);
3356                         encoding |= btrfs_file_extent_other_encoding(leaf, fi);
3357
3358                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3359                                 item_end +=
3360                                     btrfs_file_extent_num_bytes(leaf, fi);
3361                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3362                                 item_end += btrfs_file_extent_inline_len(leaf,
3363                                                                          fi);
3364                         }
3365                         item_end--;
3366                 }
3367                 if (found_type > min_type) {
3368                         del_item = 1;
3369                 } else {
3370                         if (item_end < new_size)
3371                                 break;
3372                         if (found_key.offset >= new_size)
3373                                 del_item = 1;
3374                         else
3375                                 del_item = 0;
3376                 }
3377                 found_extent = 0;
3378                 /* FIXME, shrink the extent if the ref count is only 1 */
3379                 if (found_type != BTRFS_EXTENT_DATA_KEY)
3380                         goto delete;
3381
3382                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3383                         u64 num_dec;
3384                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
3385                         if (!del_item && !encoding) {
3386                                 u64 orig_num_bytes =
3387                                         btrfs_file_extent_num_bytes(leaf, fi);
3388                                 extent_num_bytes = new_size -
3389                                         found_key.offset + root->sectorsize - 1;
3390                                 extent_num_bytes = extent_num_bytes &
3391                                         ~((u64)root->sectorsize - 1);
3392                                 btrfs_set_file_extent_num_bytes(leaf, fi,
3393                                                          extent_num_bytes);
3394                                 num_dec = (orig_num_bytes -
3395                                            extent_num_bytes);
3396                                 if (root->ref_cows && extent_start != 0)
3397                                         inode_sub_bytes(inode, num_dec);
3398                                 btrfs_mark_buffer_dirty(leaf);
3399                         } else {
3400                                 extent_num_bytes =
3401                                         btrfs_file_extent_disk_num_bytes(leaf,
3402                                                                          fi);
3403                                 extent_offset = found_key.offset -
3404                                         btrfs_file_extent_offset(leaf, fi);
3405
3406                                 /* FIXME blocksize != 4096 */
3407                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
3408                                 if (extent_start != 0) {
3409                                         found_extent = 1;
3410                                         if (root->ref_cows)
3411                                                 inode_sub_bytes(inode, num_dec);
3412                                 }
3413                         }
3414                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3415                         /*
3416                          * we can't truncate inline items that have had
3417                          * special encodings
3418                          */
3419                         if (!del_item &&
3420                             btrfs_file_extent_compression(leaf, fi) == 0 &&
3421                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
3422                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
3423                                 u32 size = new_size - found_key.offset;
3424
3425                                 if (root->ref_cows) {
3426                                         inode_sub_bytes(inode, item_end + 1 -
3427                                                         new_size);
3428                                 }
3429                                 size =
3430                                     btrfs_file_extent_calc_inline_size(size);
3431                                 ret = btrfs_truncate_item(trans, root, path,
3432                                                           size, 1);
3433                                 BUG_ON(ret);
3434                         } else if (root->ref_cows) {
3435                                 inode_sub_bytes(inode, item_end + 1 -
3436                                                 found_key.offset);
3437                         }
3438                 }
3439 delete:
3440                 if (del_item) {
3441                         if (!pending_del_nr) {
3442                                 /* no pending yet, add ourselves */
3443                                 pending_del_slot = path->slots[0];
3444                                 pending_del_nr = 1;
3445                         } else if (pending_del_nr &&
3446                                    path->slots[0] + 1 == pending_del_slot) {
3447                                 /* hop on the pending chunk */
3448                                 pending_del_nr++;
3449                                 pending_del_slot = path->slots[0];
3450                         } else {
3451                                 BUG();
3452                         }
3453                 } else {
3454                         break;
3455                 }
3456                 if (found_extent && (root->ref_cows ||
3457                                      root == root->fs_info->tree_root)) {
3458                         btrfs_set_path_blocking(path);
3459                         ret = btrfs_free_extent(trans, root, extent_start,
3460                                                 extent_num_bytes, 0,
3461                                                 btrfs_header_owner(leaf),
3462                                                 inode->i_ino, extent_offset);
3463                         BUG_ON(ret);
3464                 }
3465
3466                 if (found_type == BTRFS_INODE_ITEM_KEY)
3467                         break;
3468
3469                 if (path->slots[0] == 0 ||
3470                     path->slots[0] != pending_del_slot) {
3471                         if (root->ref_cows) {
3472                                 err = -EAGAIN;
3473                                 goto out;
3474                         }
3475                         if (pending_del_nr) {
3476                                 ret = btrfs_del_items(trans, root, path,
3477                                                 pending_del_slot,
3478                                                 pending_del_nr);
3479                                 BUG_ON(ret);
3480                                 pending_del_nr = 0;
3481                         }
3482                         btrfs_release_path(root, path);
3483                         goto search_again;
3484                 } else {
3485                         path->slots[0]--;
3486                 }
3487         }
3488 out:
3489         if (pending_del_nr) {
3490                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
3491                                       pending_del_nr);
3492                 BUG_ON(ret);
3493         }
3494         btrfs_free_path(path);
3495         return err;
3496 }
3497
3498 /*
3499  * taken from block_truncate_page, but does cow as it zeros out
3500  * any bytes left in the last page in the file.
3501  */
3502 static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
3503 {
3504         struct inode *inode = mapping->host;
3505         struct btrfs_root *root = BTRFS_I(inode)->root;
3506         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3507         struct btrfs_ordered_extent *ordered;
3508         struct extent_state *cached_state = NULL;
3509         char *kaddr;
3510         u32 blocksize = root->sectorsize;
3511         pgoff_t index = from >> PAGE_CACHE_SHIFT;
3512         unsigned offset = from & (PAGE_CACHE_SIZE-1);
3513         struct page *page;
3514         int ret = 0;
3515         u64 page_start;
3516         u64 page_end;
3517
3518         if ((offset & (blocksize - 1)) == 0)
3519                 goto out;
3520         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
3521         if (ret)
3522                 goto out;
3523
3524         ret = -ENOMEM;
3525 again:
3526         page = grab_cache_page(mapping, index);
3527         if (!page) {
3528                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
3529                 goto out;
3530         }
3531
3532         page_start = page_offset(page);
3533         page_end = page_start + PAGE_CACHE_SIZE - 1;
3534
3535         if (!PageUptodate(page)) {
3536                 ret = btrfs_readpage(NULL, page);
3537                 lock_page(page);
3538                 if (page->mapping != mapping) {
3539                         unlock_page(page);
3540                         page_cache_release(page);
3541                         goto again;
3542                 }
3543                 if (!PageUptodate(page)) {
3544                         ret = -EIO;
3545                         goto out_unlock;
3546                 }
3547         }
3548         wait_on_page_writeback(page);
3549
3550         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state,
3551                          GFP_NOFS);
3552         set_page_extent_mapped(page);
3553
3554         ordered = btrfs_lookup_ordered_extent(inode, page_start);
3555         if (ordered) {
3556                 unlock_extent_cached(io_tree, page_start, page_end,
3557                                      &cached_state, GFP_NOFS);
3558                 unlock_page(page);
3559                 page_cache_release(page);
3560                 btrfs_start_ordered_extent(inode, ordered, 1);
3561                 btrfs_put_ordered_extent(ordered);
3562                 goto again;
3563         }
3564
3565         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
3566                           EXTENT_DIRTY | EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING,
3567                           0, 0, &cached_state, GFP_NOFS);
3568
3569         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
3570                                         &cached_state);
3571         if (ret) {
3572                 unlock_extent_cached(io_tree, page_start, page_end,
3573                                      &cached_state, GFP_NOFS);
3574                 goto out_unlock;
3575         }
3576
3577         ret = 0;
3578         if (offset != PAGE_CACHE_SIZE) {
3579                 kaddr = kmap(page);
3580                 memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
3581                 flush_dcache_page(page);
3582                 kunmap(page);
3583         }
3584         ClearPageChecked(page);
3585         set_page_dirty(page);
3586         unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
3587                              GFP_NOFS);
3588
3589 out_unlock:
3590         if (ret)
3591                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
3592         unlock_page(page);
3593         page_cache_release(page);
3594 out:
3595         return ret;
3596 }
3597
3598 /*
3599  * This function puts in dummy file extents for the area we're creating a hole
3600  * for.  So if we are truncating this file to a larger size we need to insert
3601  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
3602  * the range between oldsize and size
3603  */
3604 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
3605 {
3606         struct btrfs_trans_handle *trans;
3607         struct btrfs_root *root = BTRFS_I(inode)->root;
3608         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3609         struct extent_map *em = NULL;
3610         struct extent_state *cached_state = NULL;
3611         u64 mask = root->sectorsize - 1;
3612         u64 hole_start = (oldsize + mask) & ~mask;
3613         u64 block_end = (size + mask) & ~mask;
3614         u64 last_byte;
3615         u64 cur_offset;
3616         u64 hole_size;
3617         int err = 0;
3618
3619         if (size <= hole_start)
3620                 return 0;
3621
3622         while (1) {
3623                 struct btrfs_ordered_extent *ordered;
3624                 btrfs_wait_ordered_range(inode, hole_start,
3625                                          block_end - hole_start);
3626                 lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
3627                                  &cached_state, GFP_NOFS);
3628                 ordered = btrfs_lookup_ordered_extent(inode, hole_start);
3629                 if (!ordered)
3630                         break;
3631                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
3632                                      &cached_state, GFP_NOFS);
3633                 btrfs_put_ordered_extent(ordered);
3634         }
3635
3636         cur_offset = hole_start;
3637         while (1) {
3638                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
3639                                 block_end - cur_offset, 0);
3640                 BUG_ON(IS_ERR(em) || !em);
3641                 last_byte = min(extent_map_end(em), block_end);
3642                 last_byte = (last_byte + mask) & ~mask;
3643                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
3644                         u64 hint_byte = 0;
3645                         hole_size = last_byte - cur_offset;
3646
3647                         trans = btrfs_start_transaction(root, 2);
3648                         if (IS_ERR(trans)) {
3649                                 err = PTR_ERR(trans);
3650                                 break;
3651                         }
3652                         btrfs_set_trans_block_group(trans, inode);
3653
3654                         err = btrfs_drop_extents(trans, inode, cur_offset,
3655                                                  cur_offset + hole_size,
3656                                                  &hint_byte, 1);
3657                         if (err)
3658                                 break;
3659
3660                         err = btrfs_insert_file_extent(trans, root,
3661                                         inode->i_ino, cur_offset, 0,
3662                                         0, hole_size, 0, hole_size,
3663                                         0, 0, 0);
3664                         if (err)
3665                                 break;
3666
3667                         btrfs_drop_extent_cache(inode, hole_start,
3668                                         last_byte - 1, 0);
3669
3670                         btrfs_end_transaction(trans, root);
3671                 }
3672                 free_extent_map(em);
3673                 em = NULL;
3674                 cur_offset = last_byte;
3675                 if (cur_offset >= block_end)
3676                         break;
3677         }
3678
3679         free_extent_map(em);
3680         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
3681                              GFP_NOFS);
3682         return err;
3683 }
3684
3685 static int btrfs_setsize(struct inode *inode, loff_t newsize)
3686 {
3687         loff_t oldsize = i_size_read(inode);
3688         int ret;
3689
3690         if (newsize == oldsize)
3691                 return 0;
3692
3693         if (newsize > oldsize) {
3694                 i_size_write(inode, newsize);
3695                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
3696                 truncate_pagecache(inode, oldsize, newsize);
3697                 ret = btrfs_cont_expand(inode, oldsize, newsize);
3698                 if (ret) {
3699                         btrfs_setsize(inode, oldsize);
3700                         return ret;
3701                 }
3702
3703                 mark_inode_dirty(inode);
3704         } else {
3705
3706                 /*
3707                  * We're truncating a file that used to have good data down to
3708                  * zero. Make sure it gets into the ordered flush list so that
3709                  * any new writes get down to disk quickly.
3710                  */
3711                 if (newsize == 0)
3712                         BTRFS_I(inode)->ordered_data_close = 1;
3713
3714                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
3715                 truncate_setsize(inode, newsize);
3716                 ret = btrfs_truncate(inode);
3717         }
3718
3719         return ret;
3720 }
3721
3722 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
3723 {
3724         struct inode *inode = dentry->d_inode;
3725         struct btrfs_root *root = BTRFS_I(inode)->root;
3726         int err;
3727
3728         if (btrfs_root_readonly(root))
3729                 return -EROFS;
3730
3731         err = inode_change_ok(inode, attr);
3732         if (err)
3733                 return err;
3734
3735         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
3736                 err = btrfs_setsize(inode, attr->ia_size);
3737                 if (err)
3738                         return err;
3739         }
3740
3741         if (attr->ia_valid) {
3742                 setattr_copy(inode, attr);
3743                 mark_inode_dirty(inode);
3744
3745                 if (attr->ia_valid & ATTR_MODE)
3746                         err = btrfs_acl_chmod(inode);
3747         }
3748
3749         return err;
3750 }
3751
3752 void btrfs_evict_inode(struct inode *inode)
3753 {
3754         struct btrfs_trans_handle *trans;
3755         struct btrfs_root *root = BTRFS_I(inode)->root;
3756         unsigned long nr;
3757         int ret;
3758
3759         trace_btrfs_inode_evict(inode);
3760
3761         truncate_inode_pages(&inode->i_data, 0);
3762         if (inode->i_nlink && (btrfs_root_refs(&root->root_item) != 0 ||
3763                                root == root->fs_info->tree_root))
3764                 goto no_delete;
3765
3766         if (is_bad_inode(inode)) {
3767                 btrfs_orphan_del(NULL, inode);
3768                 goto no_delete;
3769         }
3770         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
3771         btrfs_wait_ordered_range(inode, 0, (u64)-1);
3772
3773         if (root->fs_info->log_root_recovering) {
3774                 BUG_ON(!list_empty(&BTRFS_I(inode)->i_orphan));
3775                 goto no_delete;
3776         }
3777
3778         if (inode->i_nlink > 0) {
3779                 BUG_ON(btrfs_root_refs(&root->root_item) != 0);
3780                 goto no_delete;
3781         }
3782
3783         btrfs_i_size_write(inode, 0);
3784
3785         while (1) {
3786                 trans = btrfs_start_transaction(root, 0);
3787                 BUG_ON(IS_ERR(trans));
3788                 btrfs_set_trans_block_group(trans, inode);
3789                 trans->block_rsv = root->orphan_block_rsv;
3790
3791                 ret = btrfs_block_rsv_check(trans, root,
3792                                             root->orphan_block_rsv, 0, 5);
3793                 if (ret) {
3794                         BUG_ON(ret != -EAGAIN);
3795                         ret = btrfs_commit_transaction(trans, root);
3796                         BUG_ON(ret);
3797                         continue;
3798                 }
3799
3800                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
3801                 if (ret != -EAGAIN)
3802                         break;
3803
3804                 nr = trans->blocks_used;
3805                 btrfs_end_transaction(trans, root);
3806                 trans = NULL;
3807                 btrfs_btree_balance_dirty(root, nr);
3808
3809         }
3810
3811         if (ret == 0) {
3812                 ret = btrfs_orphan_del(trans, inode);
3813                 BUG_ON(ret);
3814         }
3815
3816         nr = trans->blocks_used;
3817         btrfs_end_transaction(trans, root);
3818         btrfs_btree_balance_dirty(root, nr);
3819 no_delete:
3820         end_writeback(inode);
3821         return;
3822 }
3823
3824 /*
3825  * this returns the key found in the dir entry in the location pointer.
3826  * If no dir entries were found, location->objectid is 0.
3827  */
3828 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
3829                                struct btrfs_key *location)
3830 {
3831         const char *name = dentry->d_name.name;
3832         int namelen = dentry->d_name.len;
3833         struct btrfs_dir_item *di;
3834         struct btrfs_path *path;
3835         struct btrfs_root *root = BTRFS_I(dir)->root;
3836         int ret = 0;
3837
3838         path = btrfs_alloc_path();
3839         BUG_ON(!path);
3840
3841         di = btrfs_lookup_dir_item(NULL, root, path, dir->i_ino, name,
3842                                     namelen, 0);
3843         if (IS_ERR(di))
3844                 ret = PTR_ERR(di);
3845
3846         if (!di || IS_ERR(di))
3847                 goto out_err;
3848
3849         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
3850 out:
3851         btrfs_free_path(path);
3852         return ret;
3853 out_err:
3854         location->objectid = 0;
3855         goto out;
3856 }
3857
3858 /*
3859  * when we hit a tree root in a directory, the btrfs part of the inode
3860  * needs to be changed to reflect the root directory of the tree root.  This
3861  * is kind of like crossing a mount point.
3862  */
3863 static int fixup_tree_root_location(struct btrfs_root *root,
3864                                     struct inode *dir,
3865                                     struct dentry *dentry,
3866                                     struct btrfs_key *location,
3867                                     struct btrfs_root **sub_root)
3868 {
3869         struct btrfs_path *path;
3870         struct btrfs_root *new_root;
3871         struct btrfs_root_ref *ref;
3872         struct extent_buffer *leaf;
3873         int ret;
3874         int err = 0;
3875
3876         path = btrfs_alloc_path();
3877         if (!path) {
3878                 err = -ENOMEM;
3879                 goto out;
3880         }
3881
3882         err = -ENOENT;
3883         ret = btrfs_find_root_ref(root->fs_info->tree_root, path,
3884                                   BTRFS_I(dir)->root->root_key.objectid,
3885                                   location->objectid);
3886         if (ret) {
3887                 if (ret < 0)
3888                         err = ret;
3889                 goto out;
3890         }
3891
3892         leaf = path->nodes[0];
3893         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
3894         if (btrfs_root_ref_dirid(leaf, ref) != dir->i_ino ||
3895             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
3896                 goto out;
3897
3898         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
3899                                    (unsigned long)(ref + 1),
3900                                    dentry->d_name.len);
3901         if (ret)
3902                 goto out;
3903
3904         btrfs_release_path(root->fs_info->tree_root, path);
3905
3906         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
3907         if (IS_ERR(new_root)) {
3908                 err = PTR_ERR(new_root);
3909                 goto out;
3910         }
3911
3912         if (btrfs_root_refs(&new_root->root_item) == 0) {
3913                 err = -ENOENT;
3914                 goto out;
3915         }
3916
3917         *sub_root = new_root;
3918         location->objectid = btrfs_root_dirid(&new_root->root_item);
3919         location->type = BTRFS_INODE_ITEM_KEY;
3920         location->offset = 0;
3921         err = 0;
3922 out:
3923         btrfs_free_path(path);
3924         return err;
3925 }
3926
3927 static void inode_tree_add(struct inode *inode)
3928 {
3929         struct btrfs_root *root = BTRFS_I(inode)->root;
3930         struct btrfs_inode *entry;
3931         struct rb_node **p;
3932         struct rb_node *parent;
3933 again:
3934         p = &root->inode_tree.rb_node;
3935         parent = NULL;
3936
3937         if (inode_unhashed(inode))
3938                 return;
3939
3940         spin_lock(&root->inode_lock);
3941         while (*p) {
3942                 parent = *p;
3943                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
3944
3945                 if (inode->i_ino < entry->vfs_inode.i_ino)
3946                         p = &parent->rb_left;
3947                 else if (inode->i_ino > entry->vfs_inode.i_ino)
3948                         p = &parent->rb_right;
3949                 else {
3950                         WARN_ON(!(entry->vfs_inode.i_state &
3951                                   (I_WILL_FREE | I_FREEING)));
3952                         rb_erase(parent, &root->inode_tree);
3953                         RB_CLEAR_NODE(parent);
3954                         spin_unlock(&root->inode_lock);
3955                         goto again;
3956                 }
3957         }
3958         rb_link_node(&BTRFS_I(inode)->rb_node, parent, p);
3959         rb_insert_color(&BTRFS_I(inode)->rb_node, &root->inode_tree);
3960         spin_unlock(&root->inode_lock);
3961 }
3962
3963 static void inode_tree_del(struct inode *inode)
3964 {
3965         struct btrfs_root *root = BTRFS_I(inode)->root;
3966         int empty = 0;
3967
3968         spin_lock(&root->inode_lock);
3969         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
3970                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
3971                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
3972                 empty = RB_EMPTY_ROOT(&root->inode_tree);
3973         }
3974         spin_unlock(&root->inode_lock);
3975
3976         /*
3977          * Free space cache has inodes in the tree root, but the tree root has a
3978          * root_refs of 0, so this could end up dropping the tree root as a
3979          * snapshot, so we need the extra !root->fs_info->tree_root check to
3980          * make sure we don't drop it.
3981          */
3982         if (empty && btrfs_root_refs(&root->root_item) == 0 &&
3983             root != root->fs_info->tree_root) {
3984                 synchronize_srcu(&root->fs_info->subvol_srcu);
3985                 spin_lock(&root->inode_lock);
3986                 empty = RB_EMPTY_ROOT(&root->inode_tree);
3987                 spin_unlock(&root->inode_lock);
3988                 if (empty)
3989                         btrfs_add_dead_root(root);
3990         }
3991 }
3992
3993 int btrfs_invalidate_inodes(struct btrfs_root *root)
3994 {
3995         struct rb_node *node;
3996         struct rb_node *prev;
3997         struct btrfs_inode *entry;
3998         struct inode *inode;
3999         u64 objectid = 0;
4000
4001         WARN_ON(btrfs_root_refs(&root->root_item) != 0);
4002
4003         spin_lock(&root->inode_lock);
4004 again:
4005         node = root->inode_tree.rb_node;
4006         prev = NULL;
4007         while (node) {
4008                 prev = node;
4009                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4010
4011                 if (objectid < entry->vfs_inode.i_ino)
4012                         node = node->rb_left;
4013                 else if (objectid > entry->vfs_inode.i_ino)
4014                         node = node->rb_right;
4015                 else
4016                         break;
4017         }
4018         if (!node) {
4019                 while (prev) {
4020                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
4021                         if (objectid <= entry->vfs_inode.i_ino) {
4022                                 node = prev;
4023                                 break;
4024                         }
4025                         prev = rb_next(prev);
4026                 }
4027         }
4028         while (node) {
4029                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4030                 objectid = entry->vfs_inode.i_ino + 1;
4031                 inode = igrab(&entry->vfs_inode);
4032                 if (inode) {
4033                         spin_unlock(&root->inode_lock);
4034                         if (atomic_read(&inode->i_count) > 1)
4035                                 d_prune_aliases(inode);
4036                         /*
4037                          * btrfs_drop_inode will have it removed from
4038                          * the inode cache when its usage count
4039                          * hits zero.
4040                          */
4041                         iput(inode);
4042                         cond_resched();
4043                         spin_lock(&root->inode_lock);
4044                         goto again;
4045                 }
4046
4047                 if (cond_resched_lock(&root->inode_lock))
4048                         goto again;
4049
4050                 node = rb_next(node);
4051         }
4052         spin_unlock(&root->inode_lock);
4053         return 0;
4054 }
4055
4056 static int btrfs_init_locked_inode(struct inode *inode, void *p)
4057 {
4058         struct btrfs_iget_args *args = p;
4059         inode->i_ino = args->ino;
4060         BTRFS_I(inode)->root = args->root;
4061         btrfs_set_inode_space_info(args->root, inode);
4062         return 0;
4063 }
4064
4065 static int btrfs_find_actor(struct inode *inode, void *opaque)
4066 {
4067         struct btrfs_iget_args *args = opaque;
4068         return args->ino == inode->i_ino &&
4069                 args->root == BTRFS_I(inode)->root;
4070 }
4071
4072 static struct inode *btrfs_iget_locked(struct super_block *s,
4073                                        u64 objectid,
4074                                        struct btrfs_root *root)
4075 {
4076         struct inode *inode;
4077         struct btrfs_iget_args args;
4078         args.ino = objectid;
4079         args.root = root;
4080
4081         inode = iget5_locked(s, objectid, btrfs_find_actor,
4082                              btrfs_init_locked_inode,
4083                              (void *)&args);
4084         return inode;
4085 }
4086
4087 /* Get an inode object given its location and corresponding root.
4088  * Returns in *is_new if the inode was read from disk
4089  */
4090 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
4091                          struct btrfs_root *root, int *new)
4092 {
4093         struct inode *inode;
4094
4095         inode = btrfs_iget_locked(s, location->objectid, root);
4096         if (!inode)
4097                 return ERR_PTR(-ENOMEM);
4098
4099         if (inode->i_state & I_NEW) {
4100                 BTRFS_I(inode)->root = root;
4101                 memcpy(&BTRFS_I(inode)->location, location, sizeof(*location));
4102                 btrfs_read_locked_inode(inode);
4103                 inode_tree_add(inode);
4104                 unlock_new_inode(inode);
4105                 if (new)
4106                         *new = 1;
4107         }
4108
4109         return inode;
4110 }
4111
4112 static struct inode *new_simple_dir(struct super_block *s,
4113                                     struct btrfs_key *key,
4114                                     struct btrfs_root *root)
4115 {
4116         struct inode *inode = new_inode(s);
4117
4118         if (!inode)
4119                 return ERR_PTR(-ENOMEM);
4120
4121         BTRFS_I(inode)->root = root;
4122         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
4123         BTRFS_I(inode)->dummy_inode = 1;
4124
4125         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
4126         inode->i_op = &simple_dir_inode_operations;
4127         inode->i_fop = &simple_dir_operations;
4128         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
4129         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
4130
4131         return inode;
4132 }
4133
4134 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
4135 {
4136         struct inode *inode;
4137         struct btrfs_root *root = BTRFS_I(dir)->root;
4138         struct btrfs_root *sub_root = root;
4139         struct btrfs_key location;
4140         int index;
4141         int ret;
4142
4143         if (dentry->d_name.len > BTRFS_NAME_LEN)
4144                 return ERR_PTR(-ENAMETOOLONG);
4145
4146         ret = btrfs_inode_by_name(dir, dentry, &location);
4147
4148         if (ret < 0)
4149                 return ERR_PTR(ret);
4150
4151         if (location.objectid == 0)
4152                 return NULL;
4153
4154         if (location.type == BTRFS_INODE_ITEM_KEY) {
4155                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
4156                 return inode;
4157         }
4158
4159         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
4160
4161         index = srcu_read_lock(&root->fs_info->subvol_srcu);
4162         ret = fixup_tree_root_location(root, dir, dentry,
4163                                        &location, &sub_root);
4164         if (ret < 0) {
4165                 if (ret != -ENOENT)
4166                         inode = ERR_PTR(ret);
4167                 else
4168                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
4169         } else {
4170                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
4171         }
4172         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
4173
4174         if (!IS_ERR(inode) && root != sub_root) {
4175                 down_read(&root->fs_info->cleanup_work_sem);
4176                 if (!(inode->i_sb->s_flags & MS_RDONLY))
4177                         ret = btrfs_orphan_cleanup(sub_root);
4178                 up_read(&root->fs_info->cleanup_work_sem);
4179                 if (ret)
4180                         inode = ERR_PTR(ret);
4181         }
4182
4183         return inode;
4184 }
4185
4186 static int btrfs_dentry_delete(const struct dentry *dentry)
4187 {
4188         struct btrfs_root *root;
4189
4190         if (!dentry->d_inode && !IS_ROOT(dentry))
4191                 dentry = dentry->d_parent;
4192
4193         if (dentry->d_inode) {
4194                 root = BTRFS_I(dentry->d_inode)->root;
4195                 if (btrfs_root_refs(&root->root_item) == 0)
4196                         return 1;
4197         }
4198         return 0;
4199 }
4200
4201 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
4202                                    struct nameidata *nd)
4203 {
4204         struct inode *inode;
4205
4206         inode = btrfs_lookup_dentry(dir, dentry);
4207         if (IS_ERR(inode))
4208                 return ERR_CAST(inode);
4209
4210         return d_splice_alias(inode, dentry);
4211 }
4212
4213 static unsigned char btrfs_filetype_table[] = {
4214         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
4215 };
4216
4217 static int btrfs_real_readdir(struct file *filp, void *dirent,
4218                               filldir_t filldir)
4219 {
4220         struct inode *inode = filp->f_dentry->d_inode;
4221         struct btrfs_root *root = BTRFS_I(inode)->root;
4222         struct btrfs_item *item;
4223         struct btrfs_dir_item *di;
4224         struct btrfs_key key;
4225         struct btrfs_key found_key;
4226         struct btrfs_path *path;
4227         int ret;
4228         struct extent_buffer *leaf;
4229         int slot;
4230         unsigned char d_type;
4231         int over = 0;
4232         u32 di_cur;
4233         u32 di_total;
4234         u32 di_len;
4235         int key_type = BTRFS_DIR_INDEX_KEY;
4236         char tmp_name[32];
4237         char *name_ptr;
4238         int name_len;
4239
4240         /* FIXME, use a real flag for deciding about the key type */
4241         if (root->fs_info->tree_root == root)
4242                 key_type = BTRFS_DIR_ITEM_KEY;
4243
4244         /* special case for "." */
4245         if (filp->f_pos == 0) {
4246                 over = filldir(dirent, ".", 1,
4247                                1, inode->i_ino,
4248                                DT_DIR);
4249                 if (over)
4250                         return 0;
4251                 filp->f_pos = 1;
4252         }
4253         /* special case for .., just use the back ref */
4254         if (filp->f_pos == 1) {
4255                 u64 pino = parent_ino(filp->f_path.dentry);
4256                 over = filldir(dirent, "..", 2,
4257                                2, pino, DT_DIR);
4258                 if (over)
4259                         return 0;
4260                 filp->f_pos = 2;
4261         }
4262         path = btrfs_alloc_path();
4263         path->reada = 2;
4264
4265         btrfs_set_key_type(&key, key_type);
4266         key.offset = filp->f_pos;
4267         key.objectid = inode->i_ino;
4268
4269         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4270         if (ret < 0)
4271                 goto err;
4272
4273         while (1) {
4274                 leaf = path->nodes[0];
4275                 slot = path->slots[0];
4276                 if (slot >= btrfs_header_nritems(leaf)) {
4277                         ret = btrfs_next_leaf(root, path);
4278                         if (ret < 0)
4279                                 goto err;
4280                         else if (ret > 0)
4281                                 break;
4282                         continue;
4283                 }
4284
4285                 item = btrfs_item_nr(leaf, slot);
4286                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
4287
4288                 if (found_key.objectid != key.objectid)
4289                         break;
4290                 if (btrfs_key_type(&found_key) != key_type)
4291                         break;
4292                 if (found_key.offset < filp->f_pos)
4293                         goto next;
4294
4295                 filp->f_pos = found_key.offset;
4296
4297                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
4298                 di_cur = 0;
4299                 di_total = btrfs_item_size(leaf, item);
4300
4301                 while (di_cur < di_total) {
4302                         struct btrfs_key location;
4303
4304                         if (verify_dir_item(root, leaf, di))
4305                                 break;
4306
4307                         name_len = btrfs_dir_name_len(leaf, di);
4308                         if (name_len <= sizeof(tmp_name)) {
4309                                 name_ptr = tmp_name;
4310                         } else {
4311                                 name_ptr = kmalloc(name_len, GFP_NOFS);
4312                                 if (!name_ptr) {
4313                                         ret = -ENOMEM;
4314                                         goto err;
4315                                 }
4316                         }
4317                         read_extent_buffer(leaf, name_ptr,
4318                                            (unsigned long)(di + 1), name_len);
4319
4320                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
4321                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
4322
4323                         /* is this a reference to our own snapshot? If so
4324                          * skip it
4325                          */
4326                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
4327                             location.objectid == root->root_key.objectid) {
4328                                 over = 0;
4329                                 goto skip;
4330                         }
4331                         over = filldir(dirent, name_ptr, name_len,
4332                                        found_key.offset, location.objectid,
4333                                        d_type);
4334
4335 skip:
4336                         if (name_ptr != tmp_name)
4337                                 kfree(name_ptr);
4338
4339                         if (over)
4340                                 goto nopos;
4341                         di_len = btrfs_dir_name_len(leaf, di) +
4342                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
4343                         di_cur += di_len;
4344                         di = (struct btrfs_dir_item *)((char *)di + di_len);
4345                 }
4346 next:
4347                 path->slots[0]++;
4348         }
4349
4350         /* Reached end of directory/root. Bump pos past the last item. */
4351         if (key_type == BTRFS_DIR_INDEX_KEY)
4352                 /*
4353                  * 32-bit glibc will use getdents64, but then strtol -
4354                  * so the last number we can serve is this.
4355                  */
4356                 filp->f_pos = 0x7fffffff;
4357         else
4358                 filp->f_pos++;
4359 nopos:
4360         ret = 0;
4361 err:
4362         btrfs_free_path(path);
4363         return ret;
4364 }
4365
4366 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
4367 {
4368         struct btrfs_root *root = BTRFS_I(inode)->root;
4369         struct btrfs_trans_handle *trans;
4370         int ret = 0;
4371         bool nolock = false;
4372
4373         if (BTRFS_I(inode)->dummy_inode)
4374                 return 0;
4375
4376         smp_mb();
4377         nolock = (root->fs_info->closing && root == root->fs_info->tree_root);
4378
4379         if (wbc->sync_mode == WB_SYNC_ALL) {
4380                 if (nolock)
4381                         trans = btrfs_join_transaction_nolock(root, 1);
4382                 else
4383                         trans = btrfs_join_transaction(root, 1);
4384                 if (IS_ERR(trans))
4385                         return PTR_ERR(trans);
4386                 btrfs_set_trans_block_group(trans, inode);
4387                 if (nolock)
4388                         ret = btrfs_end_transaction_nolock(trans, root);
4389                 else
4390                         ret = btrfs_commit_transaction(trans, root);
4391         }
4392         return ret;
4393 }
4394
4395 /*
4396  * This is somewhat expensive, updating the tree every time the
4397  * inode changes.  But, it is most likely to find the inode in cache.
4398  * FIXME, needs more benchmarking...there are no reasons other than performance
4399  * to keep or drop this code.
4400  */
4401 void btrfs_dirty_inode(struct inode *inode)
4402 {
4403         struct btrfs_root *root = BTRFS_I(inode)->root;
4404         struct btrfs_trans_handle *trans;
4405         int ret;
4406
4407         if (BTRFS_I(inode)->dummy_inode)
4408                 return;
4409
4410         trans = btrfs_join_transaction(root, 1);
4411         BUG_ON(IS_ERR(trans));
4412         btrfs_set_trans_block_group(trans, inode);
4413
4414         ret = btrfs_update_inode(trans, root, inode);
4415         if (ret && ret == -ENOSPC) {
4416                 /* whoops, lets try again with the full transaction */
4417                 btrfs_end_transaction(trans, root);
4418                 trans = btrfs_start_transaction(root, 1);
4419                 if (IS_ERR(trans)) {
4420                         if (printk_ratelimit()) {
4421                                 printk(KERN_ERR "btrfs: fail to "
4422                                        "dirty  inode %lu error %ld\n",
4423                                        inode->i_ino, PTR_ERR(trans));
4424                         }
4425                         return;
4426                 }
4427                 btrfs_set_trans_block_group(trans, inode);
4428
4429                 ret = btrfs_update_inode(trans, root, inode);
4430                 if (ret) {
4431                         if (printk_ratelimit()) {
4432                                 printk(KERN_ERR "btrfs: fail to "
4433                                        "dirty  inode %lu error %d\n",
4434                                        inode->i_ino, ret);
4435                         }
4436                 }
4437         }
4438         btrfs_end_transaction(trans, root);
4439 }
4440
4441 /*
4442  * find the highest existing sequence number in a directory
4443  * and then set the in-memory index_cnt variable to reflect
4444  * free sequence numbers
4445  */
4446 static int btrfs_set_inode_index_count(struct inode *inode)
4447 {
4448         struct btrfs_root *root = BTRFS_I(inode)->root;
4449         struct btrfs_key key, found_key;
4450         struct btrfs_path *path;
4451         struct extent_buffer *leaf;
4452         int ret;
4453
4454         key.objectid = inode->i_ino;
4455         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
4456         key.offset = (u64)-1;
4457
4458         path = btrfs_alloc_path();
4459         if (!path)
4460                 return -ENOMEM;
4461
4462         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4463         if (ret < 0)
4464                 goto out;
4465         /* FIXME: we should be able to handle this */
4466         if (ret == 0)
4467                 goto out;
4468         ret = 0;
4469
4470         /*
4471          * MAGIC NUMBER EXPLANATION:
4472          * since we search a directory based on f_pos we have to start at 2
4473          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
4474          * else has to start at 2
4475          */
4476         if (path->slots[0] == 0) {
4477                 BTRFS_I(inode)->index_cnt = 2;
4478                 goto out;
4479         }
4480
4481         path->slots[0]--;
4482
4483         leaf = path->nodes[0];
4484         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4485
4486         if (found_key.objectid != inode->i_ino ||
4487             btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
4488                 BTRFS_I(inode)->index_cnt = 2;
4489                 goto out;
4490         }
4491
4492         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
4493 out:
4494         btrfs_free_path(path);
4495         return ret;
4496 }
4497
4498 /*
4499  * helper to find a free sequence number in a given directory.  This current
4500  * code is very simple, later versions will do smarter things in the btree
4501  */
4502 int btrfs_set_inode_index(struct inode *dir, u64 *index)
4503 {
4504         int ret = 0;
4505
4506         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
4507                 ret = btrfs_set_inode_index_count(dir);
4508                 if (ret)
4509                         return ret;
4510         }
4511
4512         *index = BTRFS_I(dir)->index_cnt;
4513         BTRFS_I(dir)->index_cnt++;
4514
4515         return ret;
4516 }
4517
4518 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
4519                                      struct btrfs_root *root,
4520                                      struct inode *dir,
4521                                      const char *name, int name_len,
4522                                      u64 ref_objectid, u64 objectid,
4523                                      u64 alloc_hint, int mode, u64 *index)
4524 {
4525         struct inode *inode;
4526         struct btrfs_inode_item *inode_item;
4527         struct btrfs_key *location;
4528         struct btrfs_path *path;
4529         struct btrfs_inode_ref *ref;
4530         struct btrfs_key key[2];
4531         u32 sizes[2];
4532         unsigned long ptr;
4533         int ret;
4534         int owner;
4535
4536         path = btrfs_alloc_path();
4537         BUG_ON(!path);
4538
4539         inode = new_inode(root->fs_info->sb);
4540         if (!inode) {
4541                 btrfs_free_path(path);
4542                 return ERR_PTR(-ENOMEM);
4543         }
4544
4545         if (dir) {
4546                 trace_btrfs_inode_request(dir);
4547
4548                 ret = btrfs_set_inode_index(dir, index);
4549                 if (ret) {
4550                         btrfs_free_path(path);
4551                         iput(inode);
4552                         return ERR_PTR(ret);
4553                 }
4554         }
4555         /*
4556          * index_cnt is ignored for everything but a dir,
4557          * btrfs_get_inode_index_count has an explanation for the magic
4558          * number
4559          */
4560         BTRFS_I(inode)->index_cnt = 2;
4561         BTRFS_I(inode)->root = root;
4562         BTRFS_I(inode)->generation = trans->transid;
4563         inode->i_generation = BTRFS_I(inode)->generation;
4564         btrfs_set_inode_space_info(root, inode);
4565
4566         if (mode & S_IFDIR)
4567                 owner = 0;
4568         else
4569                 owner = 1;
4570         BTRFS_I(inode)->block_group =
4571                         btrfs_find_block_group(root, 0, alloc_hint, owner);
4572
4573         key[0].objectid = objectid;
4574         btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
4575         key[0].offset = 0;
4576
4577         key[1].objectid = objectid;
4578         btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
4579         key[1].offset = ref_objectid;
4580
4581         sizes[0] = sizeof(struct btrfs_inode_item);
4582         sizes[1] = name_len + sizeof(*ref);
4583
4584         path->leave_spinning = 1;
4585         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, 2);
4586         if (ret != 0)
4587                 goto fail;
4588
4589         inode_init_owner(inode, dir, mode);
4590         inode->i_ino = objectid;
4591         inode_set_bytes(inode, 0);
4592         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
4593         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
4594                                   struct btrfs_inode_item);
4595         fill_inode_item(trans, path->nodes[0], inode_item, inode);
4596
4597         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
4598                              struct btrfs_inode_ref);
4599         btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
4600         btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
4601         ptr = (unsigned long)(ref + 1);
4602         write_extent_buffer(path->nodes[0], name, ptr, name_len);
4603
4604         btrfs_mark_buffer_dirty(path->nodes[0]);
4605         btrfs_free_path(path);
4606
4607         location = &BTRFS_I(inode)->location;
4608         location->objectid = objectid;
4609         location->offset = 0;
4610         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
4611
4612         btrfs_inherit_iflags(inode, dir);
4613
4614         if ((mode & S_IFREG)) {
4615                 if (btrfs_test_opt(root, NODATASUM))
4616                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
4617                 if (btrfs_test_opt(root, NODATACOW) ||
4618                     (BTRFS_I(dir)->flags & BTRFS_INODE_NODATACOW))
4619                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
4620         }
4621
4622         insert_inode_hash(inode);
4623         inode_tree_add(inode);
4624
4625         trace_btrfs_inode_new(inode);
4626
4627         return inode;
4628 fail:
4629         if (dir)
4630                 BTRFS_I(dir)->index_cnt--;
4631         btrfs_free_path(path);
4632         iput(inode);
4633         return ERR_PTR(ret);
4634 }
4635
4636 static inline u8 btrfs_inode_type(struct inode *inode)
4637 {
4638         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
4639 }
4640
4641 /*
4642  * utility function to add 'inode' into 'parent_inode' with
4643  * a give name and a given sequence number.
4644  * if 'add_backref' is true, also insert a backref from the
4645  * inode to the parent directory.
4646  */
4647 int btrfs_add_link(struct btrfs_trans_handle *trans,
4648                    struct inode *parent_inode, struct inode *inode,
4649                    const char *name, int name_len, int add_backref, u64 index)
4650 {
4651         int ret = 0;
4652         struct btrfs_key key;
4653         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
4654
4655         if (unlikely(inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
4656                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
4657         } else {
4658                 key.objectid = inode->i_ino;
4659                 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
4660                 key.offset = 0;
4661         }
4662
4663         if (unlikely(inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)) {
4664                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
4665                                          key.objectid, root->root_key.objectid,
4666                                          parent_inode->i_ino,
4667                                          index, name, name_len);
4668         } else if (add_backref) {
4669                 ret = btrfs_insert_inode_ref(trans, root,
4670                                              name, name_len, inode->i_ino,
4671                                              parent_inode->i_ino, index);
4672         }
4673
4674         if (ret == 0) {
4675                 ret = btrfs_insert_dir_item(trans, root, name, name_len,
4676                                             parent_inode->i_ino, &key,
4677                                             btrfs_inode_type(inode), index);
4678                 BUG_ON(ret);
4679
4680                 btrfs_i_size_write(parent_inode, parent_inode->i_size +
4681                                    name_len * 2);
4682                 parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
4683                 ret = btrfs_update_inode(trans, root, parent_inode);
4684         }
4685         return ret;
4686 }
4687
4688 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
4689                             struct inode *dir, struct dentry *dentry,
4690                             struct inode *inode, int backref, u64 index)
4691 {
4692         int err = btrfs_add_link(trans, dir, inode,
4693                                  dentry->d_name.name, dentry->d_name.len,
4694                                  backref, index);
4695         if (!err) {
4696                 d_instantiate(dentry, inode);
4697                 return 0;
4698         }
4699         if (err > 0)
4700                 err = -EEXIST;
4701         return err;
4702 }
4703
4704 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
4705                         int mode, dev_t rdev)
4706 {
4707         struct btrfs_trans_handle *trans;
4708         struct btrfs_root *root = BTRFS_I(dir)->root;
4709         struct inode *inode = NULL;
4710         int err;
4711         int drop_inode = 0;
4712         u64 objectid;
4713         unsigned long nr = 0;
4714         u64 index = 0;
4715
4716         if (!new_valid_dev(rdev))
4717                 return -EINVAL;
4718
4719         err = btrfs_find_free_objectid(NULL, root, dir->i_ino, &objectid);
4720         if (err)
4721                 return err;
4722
4723         /*
4724          * 2 for inode item and ref
4725          * 2 for dir items
4726          * 1 for xattr if selinux is on
4727          */
4728         trans = btrfs_start_transaction(root, 5);
4729         if (IS_ERR(trans))
4730                 return PTR_ERR(trans);
4731
4732         btrfs_set_trans_block_group(trans, dir);
4733
4734         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4735                                 dentry->d_name.len, dir->i_ino, objectid,
4736                                 BTRFS_I(dir)->block_group, mode, &index);
4737         if (IS_ERR(inode)) {
4738                 err = PTR_ERR(inode);
4739                 goto out_unlock;
4740         }
4741
4742         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4743         if (err) {
4744                 drop_inode = 1;
4745                 goto out_unlock;
4746         }
4747
4748         btrfs_set_trans_block_group(trans, inode);
4749         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
4750         if (err)
4751                 drop_inode = 1;
4752         else {
4753                 inode->i_op = &btrfs_special_inode_operations;
4754                 init_special_inode(inode, inode->i_mode, rdev);
4755                 btrfs_update_inode(trans, root, inode);
4756         }
4757         btrfs_update_inode_block_group(trans, inode);
4758         btrfs_update_inode_block_group(trans, dir);
4759 out_unlock:
4760         nr = trans->blocks_used;
4761         btrfs_end_transaction_throttle(trans, root);
4762         btrfs_btree_balance_dirty(root, nr);
4763         if (drop_inode) {
4764                 inode_dec_link_count(inode);
4765                 iput(inode);
4766         }
4767         return err;
4768 }
4769
4770 static int btrfs_create(struct inode *dir, struct dentry *dentry,
4771                         int mode, struct nameidata *nd)
4772 {
4773         struct btrfs_trans_handle *trans;
4774         struct btrfs_root *root = BTRFS_I(dir)->root;
4775         struct inode *inode = NULL;
4776         int drop_inode = 0;
4777         int err;
4778         unsigned long nr = 0;
4779         u64 objectid;
4780         u64 index = 0;
4781
4782         err = btrfs_find_free_objectid(NULL, root, dir->i_ino, &objectid);
4783         if (err)
4784                 return err;
4785         /*
4786          * 2 for inode item and ref
4787          * 2 for dir items
4788          * 1 for xattr if selinux is on
4789          */
4790         trans = btrfs_start_transaction(root, 5);
4791         if (IS_ERR(trans))
4792                 return PTR_ERR(trans);
4793
4794         btrfs_set_trans_block_group(trans, dir);
4795
4796         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4797                                 dentry->d_name.len, dir->i_ino, objectid,
4798                                 BTRFS_I(dir)->block_group, mode, &index);
4799         if (IS_ERR(inode)) {
4800                 err = PTR_ERR(inode);
4801                 goto out_unlock;
4802         }
4803
4804         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4805         if (err) {
4806                 drop_inode = 1;
4807                 goto out_unlock;
4808         }
4809
4810         btrfs_set_trans_block_group(trans, inode);
4811         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
4812         if (err)
4813                 drop_inode = 1;
4814         else {
4815                 inode->i_mapping->a_ops = &btrfs_aops;
4816                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
4817                 inode->i_fop = &btrfs_file_operations;
4818                 inode->i_op = &btrfs_file_inode_operations;
4819                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
4820         }
4821         btrfs_update_inode_block_group(trans, inode);
4822         btrfs_update_inode_block_group(trans, dir);
4823 out_unlock:
4824         nr = trans->blocks_used;
4825         btrfs_end_transaction_throttle(trans, root);
4826         if (drop_inode) {
4827                 inode_dec_link_count(inode);
4828                 iput(inode);
4829         }
4830         btrfs_btree_balance_dirty(root, nr);
4831         return err;
4832 }
4833
4834 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
4835                       struct dentry *dentry)
4836 {
4837         struct btrfs_trans_handle *trans;
4838         struct btrfs_root *root = BTRFS_I(dir)->root;
4839         struct inode *inode = old_dentry->d_inode;
4840         u64 index;
4841         unsigned long nr = 0;
4842         int err;
4843         int drop_inode = 0;
4844
4845         /* do not allow sys_link's with other subvols of the same device */
4846         if (root->objectid != BTRFS_I(inode)->root->objectid)
4847                 return -EXDEV;
4848
4849         if (inode->i_nlink == ~0U)
4850                 return -EMLINK;
4851
4852         err = btrfs_set_inode_index(dir, &index);
4853         if (err)
4854                 goto fail;
4855
4856         /*
4857          * 2 items for inode and inode ref
4858          * 2 items for dir items
4859          * 1 item for parent inode
4860          */
4861         trans = btrfs_start_transaction(root, 5);
4862         if (IS_ERR(trans)) {
4863                 err = PTR_ERR(trans);
4864                 goto fail;
4865         }
4866
4867         btrfs_inc_nlink(inode);
4868         inode->i_ctime = CURRENT_TIME;
4869
4870         btrfs_set_trans_block_group(trans, dir);
4871         ihold(inode);
4872
4873         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
4874
4875         if (err) {
4876                 drop_inode = 1;
4877         } else {
4878                 struct dentry *parent = dget_parent(dentry);
4879                 btrfs_update_inode_block_group(trans, dir);
4880                 err = btrfs_update_inode(trans, root, inode);
4881                 BUG_ON(err);
4882                 btrfs_log_new_name(trans, inode, NULL, parent);
4883                 dput(parent);
4884         }
4885
4886         nr = trans->blocks_used;
4887         btrfs_end_transaction_throttle(trans, root);
4888 fail:
4889         if (drop_inode) {
4890                 inode_dec_link_count(inode);
4891                 iput(inode);
4892         }
4893         btrfs_btree_balance_dirty(root, nr);
4894         return err;
4895 }
4896
4897 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
4898 {
4899         struct inode *inode = NULL;
4900         struct btrfs_trans_handle *trans;
4901         struct btrfs_root *root = BTRFS_I(dir)->root;
4902         int err = 0;
4903         int drop_on_err = 0;
4904         u64 objectid = 0;
4905         u64 index = 0;
4906         unsigned long nr = 1;
4907
4908         err = btrfs_find_free_objectid(NULL, root, dir->i_ino, &objectid);
4909         if (err)
4910                 return err;
4911
4912         /*
4913          * 2 items for inode and ref
4914          * 2 items for dir items
4915          * 1 for xattr if selinux is on
4916          */
4917         trans = btrfs_start_transaction(root, 5);
4918         if (IS_ERR(trans))
4919                 return PTR_ERR(trans);
4920         btrfs_set_trans_block_group(trans, dir);
4921
4922         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4923                                 dentry->d_name.len, dir->i_ino, objectid,
4924                                 BTRFS_I(dir)->block_group, S_IFDIR | mode,
4925                                 &index);
4926         if (IS_ERR(inode)) {
4927                 err = PTR_ERR(inode);
4928                 goto out_fail;
4929         }
4930
4931         drop_on_err = 1;
4932
4933         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4934         if (err)
4935                 goto out_fail;
4936
4937         inode->i_op = &btrfs_dir_inode_operations;
4938         inode->i_fop = &btrfs_dir_file_operations;
4939         btrfs_set_trans_block_group(trans, inode);
4940
4941         btrfs_i_size_write(inode, 0);
4942         err = btrfs_update_inode(trans, root, inode);
4943         if (err)
4944                 goto out_fail;
4945
4946         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
4947                              dentry->d_name.len, 0, index);
4948         if (err)
4949                 goto out_fail;
4950
4951         d_instantiate(dentry, inode);
4952         drop_on_err = 0;
4953         btrfs_update_inode_block_group(trans, inode);
4954         btrfs_update_inode_block_group(trans, dir);
4955
4956 out_fail:
4957         nr = trans->blocks_used;
4958         btrfs_end_transaction_throttle(trans, root);
4959         if (drop_on_err)
4960                 iput(inode);
4961         btrfs_btree_balance_dirty(root, nr);
4962         return err;
4963 }
4964
4965 /* helper for btfs_get_extent.  Given an existing extent in the tree,
4966  * and an extent that you want to insert, deal with overlap and insert
4967  * the new extent into the tree.
4968  */
4969 static int merge_extent_mapping(struct extent_map_tree *em_tree,
4970                                 struct extent_map *existing,
4971                                 struct extent_map *em,
4972                                 u64 map_start, u64 map_len)
4973 {
4974         u64 start_diff;
4975
4976         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
4977         start_diff = map_start - em->start;
4978         em->start = map_start;
4979         em->len = map_len;
4980         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
4981             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
4982                 em->block_start += start_diff;
4983                 em->block_len -= start_diff;
4984         }
4985         return add_extent_mapping(em_tree, em);
4986 }
4987
4988 static noinline int uncompress_inline(struct btrfs_path *path,
4989                                       struct inode *inode, struct page *page,
4990                                       size_t pg_offset, u64 extent_offset,
4991                                       struct btrfs_file_extent_item *item)
4992 {
4993         int ret;
4994         struct extent_buffer *leaf = path->nodes[0];
4995         char *tmp;
4996         size_t max_size;
4997         unsigned long inline_size;
4998         unsigned long ptr;
4999         int compress_type;
5000
5001         WARN_ON(pg_offset != 0);
5002         compress_type = btrfs_file_extent_compression(leaf, item);
5003         max_size = btrfs_file_extent_ram_bytes(leaf, item);
5004         inline_size = btrfs_file_extent_inline_item_len(leaf,
5005                                         btrfs_item_nr(leaf, path->slots[0]));
5006         tmp = kmalloc(inline_size, GFP_NOFS);
5007         if (!tmp)
5008                 return -ENOMEM;
5009         ptr = btrfs_file_extent_inline_start(item);
5010
5011         read_extent_buffer(leaf, tmp, ptr, inline_size);
5012
5013         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
5014         ret = btrfs_decompress(compress_type, tmp, page,
5015                                extent_offset, inline_size, max_size);
5016         if (ret) {
5017                 char *kaddr = kmap_atomic(page, KM_USER0);
5018                 unsigned long copy_size = min_t(u64,
5019                                   PAGE_CACHE_SIZE - pg_offset,
5020                                   max_size - extent_offset);
5021                 memset(kaddr + pg_offset, 0, copy_size);
5022                 kunmap_atomic(kaddr, KM_USER0);
5023         }
5024         kfree(tmp);
5025         return 0;
5026 }
5027
5028 /*
5029  * a bit scary, this does extent mapping from logical file offset to the disk.
5030  * the ugly parts come from merging extents from the disk with the in-ram
5031  * representation.  This gets more complex because of the data=ordered code,
5032  * where the in-ram extents might be locked pending data=ordered completion.
5033  *
5034  * This also copies inline extents directly into the page.
5035  */
5036
5037 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
5038                                     size_t pg_offset, u64 start, u64 len,
5039                                     int create)
5040 {
5041         int ret;
5042         int err = 0;
5043         u64 bytenr;
5044         u64 extent_start = 0;
5045         u64 extent_end = 0;
5046         u64 objectid = inode->i_ino;
5047         u32 found_type;
5048         struct btrfs_path *path = NULL;
5049         struct btrfs_root *root = BTRFS_I(inode)->root;
5050         struct btrfs_file_extent_item *item;
5051         struct extent_buffer *leaf;
5052         struct btrfs_key found_key;
5053         struct extent_map *em = NULL;
5054         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
5055         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
5056         struct btrfs_trans_handle *trans = NULL;
5057         int compress_type;
5058
5059 again:
5060         read_lock(&em_tree->lock);
5061         em = lookup_extent_mapping(em_tree, start, len);
5062         if (em)
5063                 em->bdev = root->fs_info->fs_devices->latest_bdev;
5064         read_unlock(&em_tree->lock);
5065
5066         if (em) {
5067                 if (em->start > start || em->start + em->len <= start)
5068                         free_extent_map(em);
5069                 else if (em->block_start == EXTENT_MAP_INLINE && page)
5070                         free_extent_map(em);
5071                 else
5072                         goto out;
5073         }
5074         em = alloc_extent_map(GFP_NOFS);
5075         if (!em) {
5076                 err = -ENOMEM;
5077                 goto out;
5078         }
5079         em->bdev = root->fs_info->fs_devices->latest_bdev;
5080         em->start = EXTENT_MAP_HOLE;
5081         em->orig_start = EXTENT_MAP_HOLE;
5082         em->len = (u64)-1;
5083         em->block_len = (u64)-1;
5084
5085         if (!path) {
5086                 path = btrfs_alloc_path();
5087                 BUG_ON(!path);
5088         }
5089
5090         ret = btrfs_lookup_file_extent(trans, root, path,
5091                                        objectid, start, trans != NULL);
5092         if (ret < 0) {
5093                 err = ret;
5094                 goto out;
5095         }
5096
5097         if (ret != 0) {
5098                 if (path->slots[0] == 0)
5099                         goto not_found;
5100                 path->slots[0]--;
5101         }
5102
5103         leaf = path->nodes[0];
5104         item = btrfs_item_ptr(leaf, path->slots[0],
5105                               struct btrfs_file_extent_item);
5106         /* are we inside the extent that was found? */
5107         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5108         found_type = btrfs_key_type(&found_key);
5109         if (found_key.objectid != objectid ||
5110             found_type != BTRFS_EXTENT_DATA_KEY) {
5111                 goto not_found;
5112         }
5113
5114         found_type = btrfs_file_extent_type(leaf, item);
5115         extent_start = found_key.offset;
5116         compress_type = btrfs_file_extent_compression(leaf, item);
5117         if (found_type == BTRFS_FILE_EXTENT_REG ||
5118             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
5119                 extent_end = extent_start +
5120                        btrfs_file_extent_num_bytes(leaf, item);
5121         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
5122                 size_t size;
5123                 size = btrfs_file_extent_inline_len(leaf, item);
5124                 extent_end = (extent_start + size + root->sectorsize - 1) &
5125                         ~((u64)root->sectorsize - 1);
5126         }
5127
5128         if (start >= extent_end) {
5129                 path->slots[0]++;
5130                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
5131                         ret = btrfs_next_leaf(root, path);
5132                         if (ret < 0) {
5133                                 err = ret;
5134                                 goto out;
5135                         }
5136                         if (ret > 0)
5137                                 goto not_found;
5138                         leaf = path->nodes[0];
5139                 }
5140                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5141                 if (found_key.objectid != objectid ||
5142                     found_key.type != BTRFS_EXTENT_DATA_KEY)
5143                         goto not_found;
5144                 if (start + len <= found_key.offset)
5145                         goto not_found;
5146                 em->start = start;
5147                 em->len = found_key.offset - start;
5148                 goto not_found_em;
5149         }
5150
5151         if (found_type == BTRFS_FILE_EXTENT_REG ||
5152             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
5153                 em->start = extent_start;
5154                 em->len = extent_end - extent_start;
5155                 em->orig_start = extent_start -
5156                                  btrfs_file_extent_offset(leaf, item);
5157                 bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
5158                 if (bytenr == 0) {
5159                         em->block_start = EXTENT_MAP_HOLE;
5160                         goto insert;
5161                 }
5162                 if (compress_type != BTRFS_COMPRESS_NONE) {
5163                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
5164                         em->compress_type = compress_type;
5165                         em->block_start = bytenr;
5166                         em->block_len = btrfs_file_extent_disk_num_bytes(leaf,
5167                                                                          item);
5168                 } else {
5169                         bytenr += btrfs_file_extent_offset(leaf, item);
5170                         em->block_start = bytenr;
5171                         em->block_len = em->len;
5172                         if (found_type == BTRFS_FILE_EXTENT_PREALLOC)
5173                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
5174                 }
5175                 goto insert;
5176         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
5177                 unsigned long ptr;
5178                 char *map;
5179                 size_t size;
5180                 size_t extent_offset;
5181                 size_t copy_size;
5182
5183                 em->block_start = EXTENT_MAP_INLINE;
5184                 if (!page || create) {
5185                         em->start = extent_start;
5186                         em->len = extent_end - extent_start;
5187                         goto out;
5188                 }
5189
5190                 size = btrfs_file_extent_inline_len(leaf, item);
5191                 extent_offset = page_offset(page) + pg_offset - extent_start;
5192                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
5193                                 size - extent_offset);
5194                 em->start = extent_start + extent_offset;
5195                 em->len = (copy_size + root->sectorsize - 1) &
5196                         ~((u64)root->sectorsize - 1);
5197                 em->orig_start = EXTENT_MAP_INLINE;
5198                 if (compress_type) {
5199                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
5200                         em->compress_type = compress_type;
5201                 }
5202                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
5203                 if (create == 0 && !PageUptodate(page)) {
5204                         if (btrfs_file_extent_compression(leaf, item) !=
5205                             BTRFS_COMPRESS_NONE) {
5206                                 ret = uncompress_inline(path, inode, page,
5207                                                         pg_offset,
5208                                                         extent_offset, item);
5209                                 BUG_ON(ret);
5210                         } else {
5211                                 map = kmap(page);
5212                                 read_extent_buffer(leaf, map + pg_offset, ptr,
5213                                                    copy_size);
5214                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
5215                                         memset(map + pg_offset + copy_size, 0,
5216                                                PAGE_CACHE_SIZE - pg_offset -
5217                                                copy_size);
5218                                 }
5219                                 kunmap(page);
5220                         }
5221                         flush_dcache_page(page);
5222                 } else if (create && PageUptodate(page)) {
5223                         WARN_ON(1);
5224                         if (!trans) {
5225                                 kunmap(page);
5226                                 free_extent_map(em);
5227                                 em = NULL;
5228                                 btrfs_release_path(root, path);
5229                                 trans = btrfs_join_transaction(root, 1);
5230                                 if (IS_ERR(trans))
5231                                         return ERR_CAST(trans);
5232                                 goto again;
5233                         }
5234                         map = kmap(page);
5235                         write_extent_buffer(leaf, map + pg_offset, ptr,
5236                                             copy_size);
5237                         kunmap(page);
5238                         btrfs_mark_buffer_dirty(leaf);
5239                 }
5240                 set_extent_uptodate(io_tree, em->start,
5241                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
5242                 goto insert;
5243         } else {
5244                 printk(KERN_ERR "btrfs unknown found_type %d\n", found_type);
5245                 WARN_ON(1);
5246         }
5247 not_found:
5248         em->start = start;
5249         em->len = len;
5250 not_found_em:
5251         em->block_start = EXTENT_MAP_HOLE;
5252         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
5253 insert:
5254         btrfs_release_path(root, path);
5255         if (em->start > start || extent_map_end(em) <= start) {
5256                 printk(KERN_ERR "Btrfs: bad extent! em: [%llu %llu] passed "
5257                        "[%llu %llu]\n", (unsigned long long)em->start,
5258                        (unsigned long long)em->len,
5259                        (unsigned long long)start,
5260                        (unsigned long long)len);
5261                 err = -EIO;
5262                 goto out;
5263         }
5264
5265         err = 0;
5266         write_lock(&em_tree->lock);
5267         ret = add_extent_mapping(em_tree, em);
5268         /* it is possible that someone inserted the extent into the tree
5269          * while we had the lock dropped.  It is also possible that
5270          * an overlapping map exists in the tree
5271          */
5272         if (ret == -EEXIST) {
5273                 struct extent_map *existing;
5274
5275                 ret = 0;
5276
5277                 existing = lookup_extent_mapping(em_tree, start, len);
5278                 if (existing && (existing->start > start ||
5279                     existing->start + existing->len <= start)) {
5280                         free_extent_map(existing);
5281                         existing = NULL;
5282                 }
5283                 if (!existing) {
5284                         existing = lookup_extent_mapping(em_tree, em->start,
5285                                                          em->len);
5286                         if (existing) {
5287                                 err = merge_extent_mapping(em_tree, existing,
5288                                                            em, start,
5289                                                            root->sectorsize);
5290                                 free_extent_map(existing);
5291                                 if (err) {
5292                                         free_extent_map(em);
5293                                         em = NULL;
5294                                 }
5295                         } else {
5296                                 err = -EIO;
5297                                 free_extent_map(em);
5298                                 em = NULL;
5299                         }
5300                 } else {
5301                         free_extent_map(em);
5302                         em = existing;
5303                         err = 0;
5304                 }
5305         }
5306         write_unlock(&em_tree->lock);
5307 out:
5308
5309         trace_btrfs_get_extent(root, em);
5310
5311         if (path)
5312                 btrfs_free_path(path);
5313         if (trans) {
5314                 ret = btrfs_end_transaction(trans, root);
5315                 if (!err)
5316                         err = ret;
5317         }
5318         if (err) {
5319                 free_extent_map(em);
5320                 return ERR_PTR(err);
5321         }
5322         return em;
5323 }
5324
5325 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
5326                                            size_t pg_offset, u64 start, u64 len,
5327                                            int create)
5328 {
5329         struct extent_map *em;
5330         struct extent_map *hole_em = NULL;
5331         u64 range_start = start;
5332         u64 end;
5333         u64 found;
5334         u64 found_end;
5335         int err = 0;
5336
5337         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
5338         if (IS_ERR(em))
5339                 return em;
5340         if (em) {
5341                 /*
5342                  * if our em maps to a hole, there might
5343                  * actually be delalloc bytes behind it
5344                  */
5345                 if (em->block_start != EXTENT_MAP_HOLE)
5346                         return em;
5347                 else
5348                         hole_em = em;
5349         }
5350
5351         /* check to see if we've wrapped (len == -1 or similar) */
5352         end = start + len;
5353         if (end < start)
5354                 end = (u64)-1;
5355         else
5356                 end -= 1;
5357
5358         em = NULL;
5359
5360         /* ok, we didn't find anything, lets look for delalloc */
5361         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
5362                                  end, len, EXTENT_DELALLOC, 1);
5363         found_end = range_start + found;
5364         if (found_end < range_start)
5365                 found_end = (u64)-1;
5366
5367         /*
5368          * we didn't find anything useful, return
5369          * the original results from get_extent()
5370          */
5371         if (range_start > end || found_end <= start) {
5372                 em = hole_em;
5373                 hole_em = NULL;
5374                 goto out;
5375         }
5376
5377         /* adjust the range_start to make sure it doesn't
5378          * go backwards from the start they passed in
5379          */
5380         range_start = max(start,range_start);
5381         found = found_end - range_start;
5382
5383         if (found > 0) {
5384                 u64 hole_start = start;
5385                 u64 hole_len = len;
5386
5387                 em = alloc_extent_map(GFP_NOFS);
5388                 if (!em) {
5389                         err = -ENOMEM;
5390                         goto out;
5391                 }
5392                 /*
5393                  * when btrfs_get_extent can't find anything it
5394                  * returns one huge hole
5395                  *
5396                  * make sure what it found really fits our range, and
5397                  * adjust to make sure it is based on the start from
5398                  * the caller
5399                  */
5400                 if (hole_em) {
5401                         u64 calc_end = extent_map_end(hole_em);
5402
5403                         if (calc_end <= start || (hole_em->start > end)) {
5404                                 free_extent_map(hole_em);
5405                                 hole_em = NULL;
5406                         } else {
5407                                 hole_start = max(hole_em->start, start);
5408                                 hole_len = calc_end - hole_start;
5409                         }
5410                 }
5411                 em->bdev = NULL;
5412                 if (hole_em && range_start > hole_start) {
5413                         /* our hole starts before our delalloc, so we
5414                          * have to return just the parts of the hole
5415                          * that go until  the delalloc starts
5416                          */
5417                         em->len = min(hole_len,
5418                                       range_start - hole_start);
5419                         em->start = hole_start;
5420                         em->orig_start = hole_start;
5421                         /*
5422                          * don't adjust block start at all,
5423                          * it is fixed at EXTENT_MAP_HOLE
5424                          */
5425                         em->block_start = hole_em->block_start;
5426                         em->block_len = hole_len;
5427                 } else {
5428                         em->start = range_start;
5429                         em->len = found;
5430                         em->orig_start = range_start;
5431                         em->block_start = EXTENT_MAP_DELALLOC;
5432                         em->block_len = found;
5433                 }
5434         } else if (hole_em) {
5435                 return hole_em;
5436         }
5437 out:
5438
5439         free_extent_map(hole_em);
5440         if (err) {
5441                 free_extent_map(em);
5442                 return ERR_PTR(err);
5443         }
5444         return em;
5445 }
5446
5447 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
5448                                                   struct extent_map *em,
5449                                                   u64 start, u64 len)
5450 {
5451         struct btrfs_root *root = BTRFS_I(inode)->root;
5452         struct btrfs_trans_handle *trans;
5453         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
5454         struct btrfs_key ins;
5455         u64 alloc_hint;
5456         int ret;
5457         bool insert = false;
5458
5459         /*
5460          * Ok if the extent map we looked up is a hole and is for the exact
5461          * range we want, there is no reason to allocate a new one, however if
5462          * it is not right then we need to free this one and drop the cache for
5463          * our range.
5464          */
5465         if (em->block_start != EXTENT_MAP_HOLE || em->start != start ||
5466             em->len != len) {
5467                 free_extent_map(em);
5468                 em = NULL;
5469                 insert = true;
5470                 btrfs_drop_extent_cache(inode, start, start + len - 1, 0);
5471         }
5472
5473         trans = btrfs_join_transaction(root, 0);
5474         if (IS_ERR(trans))
5475                 return ERR_CAST(trans);
5476
5477         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
5478
5479         alloc_hint = get_extent_allocation_hint(inode, start, len);
5480         ret = btrfs_reserve_extent(trans, root, len, root->sectorsize, 0,
5481                                    alloc_hint, (u64)-1, &ins, 1);
5482         if (ret) {
5483                 em = ERR_PTR(ret);
5484                 goto out;
5485         }
5486
5487         if (!em) {
5488                 em = alloc_extent_map(GFP_NOFS);
5489                 if (!em) {
5490                         em = ERR_PTR(-ENOMEM);
5491                         goto out;
5492                 }
5493         }
5494
5495         em->start = start;
5496         em->orig_start = em->start;
5497         em->len = ins.offset;
5498
5499         em->block_start = ins.objectid;
5500         em->block_len = ins.offset;
5501         em->bdev = root->fs_info->fs_devices->latest_bdev;
5502
5503         /*
5504          * We need to do this because if we're using the original em we searched
5505          * for, we could have EXTENT_FLAG_VACANCY set, and we don't want that.
5506          */
5507         em->flags = 0;
5508         set_bit(EXTENT_FLAG_PINNED, &em->flags);
5509
5510         while (insert) {
5511                 write_lock(&em_tree->lock);
5512                 ret = add_extent_mapping(em_tree, em);
5513                 write_unlock(&em_tree->lock);
5514                 if (ret != -EEXIST)
5515                         break;
5516                 btrfs_drop_extent_cache(inode, start, start + em->len - 1, 0);
5517         }
5518
5519         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
5520                                            ins.offset, ins.offset, 0);
5521         if (ret) {
5522                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
5523                 em = ERR_PTR(ret);
5524         }
5525 out:
5526         btrfs_end_transaction(trans, root);
5527         return em;
5528 }
5529
5530 /*
5531  * returns 1 when the nocow is safe, < 1 on error, 0 if the
5532  * block must be cow'd
5533  */
5534 static noinline int can_nocow_odirect(struct btrfs_trans_handle *trans,
5535                                       struct inode *inode, u64 offset, u64 len)
5536 {
5537         struct btrfs_path *path;
5538         int ret;
5539         struct extent_buffer *leaf;
5540         struct btrfs_root *root = BTRFS_I(inode)->root;
5541         struct btrfs_file_extent_item *fi;
5542         struct btrfs_key key;
5543         u64 disk_bytenr;
5544         u64 backref_offset;
5545         u64 extent_end;
5546         u64 num_bytes;
5547         int slot;
5548         int found_type;
5549
5550         path = btrfs_alloc_path();
5551         if (!path)
5552                 return -ENOMEM;
5553
5554         ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
5555                                        offset, 0);
5556         if (ret < 0)
5557                 goto out;
5558
5559         slot = path->slots[0];
5560         if (ret == 1) {
5561                 if (slot == 0) {
5562                         /* can't find the item, must cow */
5563                         ret = 0;
5564                         goto out;
5565                 }
5566                 slot--;
5567         }
5568         ret = 0;
5569         leaf = path->nodes[0];
5570         btrfs_item_key_to_cpu(leaf, &key, slot);
5571         if (key.objectid != inode->i_ino ||
5572             key.type != BTRFS_EXTENT_DATA_KEY) {
5573                 /* not our file or wrong item type, must cow */
5574                 goto out;
5575         }
5576
5577         if (key.offset > offset) {
5578                 /* Wrong offset, must cow */
5579                 goto out;
5580         }
5581
5582         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
5583         found_type = btrfs_file_extent_type(leaf, fi);
5584         if (found_type != BTRFS_FILE_EXTENT_REG &&
5585             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
5586                 /* not a regular extent, must cow */
5587                 goto out;
5588         }
5589         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
5590         backref_offset = btrfs_file_extent_offset(leaf, fi);
5591
5592         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
5593         if (extent_end < offset + len) {
5594                 /* extent doesn't include our full range, must cow */
5595                 goto out;
5596         }
5597
5598         if (btrfs_extent_readonly(root, disk_bytenr))
5599                 goto out;
5600
5601         /*
5602          * look for other files referencing this extent, if we
5603          * find any we must cow
5604          */
5605         if (btrfs_cross_ref_exist(trans, root, inode->i_ino,
5606                                   key.offset - backref_offset, disk_bytenr))
5607                 goto out;
5608
5609         /*
5610          * adjust disk_bytenr and num_bytes to cover just the bytes
5611          * in this extent we are about to write.  If there
5612          * are any csums in that range we have to cow in order
5613          * to keep the csums correct
5614          */
5615         disk_bytenr += backref_offset;
5616         disk_bytenr += offset - key.offset;
5617         num_bytes = min(offset + len, extent_end) - offset;
5618         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
5619                                 goto out;
5620         /*
5621          * all of the above have passed, it is safe to overwrite this extent
5622          * without cow
5623          */
5624         ret = 1;
5625 out:
5626         btrfs_free_path(path);
5627         return ret;
5628 }
5629
5630 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
5631                                    struct buffer_head *bh_result, int create)
5632 {
5633         struct extent_map *em;
5634         struct btrfs_root *root = BTRFS_I(inode)->root;
5635         u64 start = iblock << inode->i_blkbits;
5636         u64 len = bh_result->b_size;
5637         struct btrfs_trans_handle *trans;
5638
5639         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
5640         if (IS_ERR(em))
5641                 return PTR_ERR(em);
5642
5643         /*
5644          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
5645          * io.  INLINE is special, and we could probably kludge it in here, but
5646          * it's still buffered so for safety lets just fall back to the generic
5647          * buffered path.
5648     &