2 * Copyright (C) 2007 Oracle. All rights reserved.
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.
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.
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.
20 #include <linux/slab.h>
21 #include <linux/sched.h>
22 #include <linux/writeback.h>
23 #include <linux/pagemap.h>
24 #include <linux/blkdev.h>
27 #include "transaction.h"
30 #include "inode-map.h"
32 #define BTRFS_ROOT_TRANS_TAG 0
34 static noinline
void put_transaction(struct btrfs_transaction
*transaction
)
36 WARN_ON(atomic_read(&transaction
->use_count
) == 0);
37 if (atomic_dec_and_test(&transaction
->use_count
)) {
38 BUG_ON(!list_empty(&transaction
->list
));
39 memset(transaction
, 0, sizeof(*transaction
));
40 kmem_cache_free(btrfs_transaction_cachep
, transaction
);
44 static noinline
void switch_commit_root(struct btrfs_root
*root
)
46 free_extent_buffer(root
->commit_root
);
47 root
->commit_root
= btrfs_root_node(root
);
51 * either allocate a new transaction or hop into the existing one
53 static noinline
int join_transaction(struct btrfs_root
*root
, int nofail
)
55 struct btrfs_transaction
*cur_trans
;
57 spin_lock(&root
->fs_info
->trans_lock
);
58 if (root
->fs_info
->trans_no_join
) {
60 spin_unlock(&root
->fs_info
->trans_lock
);
65 cur_trans
= root
->fs_info
->running_transaction
;
67 atomic_inc(&cur_trans
->use_count
);
68 atomic_inc(&cur_trans
->num_writers
);
69 cur_trans
->num_joined
++;
70 spin_unlock(&root
->fs_info
->trans_lock
);
73 spin_unlock(&root
->fs_info
->trans_lock
);
75 cur_trans
= kmem_cache_alloc(btrfs_transaction_cachep
, GFP_NOFS
);
78 spin_lock(&root
->fs_info
->trans_lock
);
79 if (root
->fs_info
->running_transaction
) {
80 kmem_cache_free(btrfs_transaction_cachep
, cur_trans
);
81 cur_trans
= root
->fs_info
->running_transaction
;
82 atomic_inc(&cur_trans
->use_count
);
83 atomic_inc(&cur_trans
->num_writers
);
84 cur_trans
->num_joined
++;
85 spin_unlock(&root
->fs_info
->trans_lock
);
88 atomic_set(&cur_trans
->num_writers
, 1);
89 cur_trans
->num_joined
= 0;
90 init_waitqueue_head(&cur_trans
->writer_wait
);
91 init_waitqueue_head(&cur_trans
->commit_wait
);
92 cur_trans
->in_commit
= 0;
93 cur_trans
->blocked
= 0;
95 * One for this trans handle, one so it will live on until we
96 * commit the transaction.
98 atomic_set(&cur_trans
->use_count
, 2);
99 cur_trans
->commit_done
= 0;
100 cur_trans
->start_time
= get_seconds();
102 cur_trans
->delayed_refs
.root
= RB_ROOT
;
103 cur_trans
->delayed_refs
.num_entries
= 0;
104 cur_trans
->delayed_refs
.num_heads_ready
= 0;
105 cur_trans
->delayed_refs
.num_heads
= 0;
106 cur_trans
->delayed_refs
.flushing
= 0;
107 cur_trans
->delayed_refs
.run_delayed_start
= 0;
108 spin_lock_init(&cur_trans
->commit_lock
);
109 spin_lock_init(&cur_trans
->delayed_refs
.lock
);
111 INIT_LIST_HEAD(&cur_trans
->pending_snapshots
);
112 list_add_tail(&cur_trans
->list
, &root
->fs_info
->trans_list
);
113 extent_io_tree_init(&cur_trans
->dirty_pages
,
114 root
->fs_info
->btree_inode
->i_mapping
);
115 root
->fs_info
->generation
++;
116 cur_trans
->transid
= root
->fs_info
->generation
;
117 root
->fs_info
->running_transaction
= cur_trans
;
118 spin_unlock(&root
->fs_info
->trans_lock
);
124 * this does all the record keeping required to make sure that a reference
125 * counted root is properly recorded in a given transaction. This is required
126 * to make sure the old root from before we joined the transaction is deleted
127 * when the transaction commits
129 static int record_root_in_trans(struct btrfs_trans_handle
*trans
,
130 struct btrfs_root
*root
)
132 if (root
->ref_cows
&& root
->last_trans
< trans
->transid
) {
133 WARN_ON(root
== root
->fs_info
->extent_root
);
134 WARN_ON(root
->commit_root
!= root
->node
);
137 * see below for in_trans_setup usage rules
138 * we have the reloc mutex held now, so there
139 * is only one writer in this function
141 root
->in_trans_setup
= 1;
143 /* make sure readers find in_trans_setup before
144 * they find our root->last_trans update
148 spin_lock(&root
->fs_info
->fs_roots_radix_lock
);
149 if (root
->last_trans
== trans
->transid
) {
150 spin_unlock(&root
->fs_info
->fs_roots_radix_lock
);
153 radix_tree_tag_set(&root
->fs_info
->fs_roots_radix
,
154 (unsigned long)root
->root_key
.objectid
,
155 BTRFS_ROOT_TRANS_TAG
);
156 spin_unlock(&root
->fs_info
->fs_roots_radix_lock
);
157 root
->last_trans
= trans
->transid
;
159 /* this is pretty tricky. We don't want to
160 * take the relocation lock in btrfs_record_root_in_trans
161 * unless we're really doing the first setup for this root in
164 * Normally we'd use root->last_trans as a flag to decide
165 * if we want to take the expensive mutex.
167 * But, we have to set root->last_trans before we
168 * init the relocation root, otherwise, we trip over warnings
169 * in ctree.c. The solution used here is to flag ourselves
170 * with root->in_trans_setup. When this is 1, we're still
171 * fixing up the reloc trees and everyone must wait.
173 * When this is zero, they can trust root->last_trans and fly
174 * through btrfs_record_root_in_trans without having to take the
175 * lock. smp_wmb() makes sure that all the writes above are
176 * done before we pop in the zero below
178 btrfs_init_reloc_root(trans
, root
);
180 root
->in_trans_setup
= 0;
186 int btrfs_record_root_in_trans(struct btrfs_trans_handle
*trans
,
187 struct btrfs_root
*root
)
193 * see record_root_in_trans for comments about in_trans_setup usage
197 if (root
->last_trans
== trans
->transid
&&
198 !root
->in_trans_setup
)
201 mutex_lock(&root
->fs_info
->reloc_mutex
);
202 record_root_in_trans(trans
, root
);
203 mutex_unlock(&root
->fs_info
->reloc_mutex
);
208 /* wait for commit against the current transaction to become unblocked
209 * when this is done, it is safe to start a new transaction, but the current
210 * transaction might not be fully on disk.
212 static void wait_current_trans(struct btrfs_root
*root
)
214 struct btrfs_transaction
*cur_trans
;
216 spin_lock(&root
->fs_info
->trans_lock
);
217 cur_trans
= root
->fs_info
->running_transaction
;
218 if (cur_trans
&& cur_trans
->blocked
) {
219 atomic_inc(&cur_trans
->use_count
);
220 spin_unlock(&root
->fs_info
->trans_lock
);
222 wait_event(root
->fs_info
->transaction_wait
,
223 !cur_trans
->blocked
);
224 put_transaction(cur_trans
);
226 spin_unlock(&root
->fs_info
->trans_lock
);
230 enum btrfs_trans_type
{
237 static int may_wait_transaction(struct btrfs_root
*root
, int type
)
239 if (root
->fs_info
->log_root_recovering
)
242 if (type
== TRANS_USERSPACE
)
245 if (type
== TRANS_START
&&
246 !atomic_read(&root
->fs_info
->open_ioctl_trans
))
252 static struct btrfs_trans_handle
*start_transaction(struct btrfs_root
*root
,
253 u64 num_items
, int type
)
255 struct btrfs_trans_handle
*h
;
256 struct btrfs_transaction
*cur_trans
;
260 if (root
->fs_info
->fs_state
& BTRFS_SUPER_FLAG_ERROR
)
261 return ERR_PTR(-EROFS
);
263 if (current
->journal_info
) {
264 WARN_ON(type
!= TRANS_JOIN
&& type
!= TRANS_JOIN_NOLOCK
);
265 h
= current
->journal_info
;
267 h
->orig_rsv
= h
->block_rsv
;
273 * Do the reservation before we join the transaction so we can do all
274 * the appropriate flushing if need be.
276 if (num_items
> 0 && root
!= root
->fs_info
->chunk_root
) {
277 num_bytes
= btrfs_calc_trans_metadata_size(root
, num_items
);
278 ret
= btrfs_block_rsv_add(NULL
, root
,
279 &root
->fs_info
->trans_block_rsv
,
285 h
= kmem_cache_alloc(btrfs_trans_handle_cachep
, GFP_NOFS
);
287 return ERR_PTR(-ENOMEM
);
289 if (may_wait_transaction(root
, type
))
290 wait_current_trans(root
);
293 ret
= join_transaction(root
, type
== TRANS_JOIN_NOLOCK
);
295 wait_current_trans(root
);
296 } while (ret
== -EBUSY
);
299 kmem_cache_free(btrfs_trans_handle_cachep
, h
);
303 cur_trans
= root
->fs_info
->running_transaction
;
305 h
->transid
= cur_trans
->transid
;
306 h
->transaction
= cur_trans
;
308 h
->bytes_reserved
= 0;
309 h
->delayed_ref_updates
= 0;
315 if (cur_trans
->blocked
&& may_wait_transaction(root
, type
)) {
316 btrfs_commit_transaction(h
, root
);
321 h
->block_rsv
= &root
->fs_info
->trans_block_rsv
;
322 h
->bytes_reserved
= num_bytes
;
326 btrfs_record_root_in_trans(h
, root
);
328 if (!current
->journal_info
&& type
!= TRANS_USERSPACE
)
329 current
->journal_info
= h
;
333 struct btrfs_trans_handle
*btrfs_start_transaction(struct btrfs_root
*root
,
336 return start_transaction(root
, num_items
, TRANS_START
);
338 struct btrfs_trans_handle
*btrfs_join_transaction(struct btrfs_root
*root
)
340 return start_transaction(root
, 0, TRANS_JOIN
);
343 struct btrfs_trans_handle
*btrfs_join_transaction_nolock(struct btrfs_root
*root
)
345 return start_transaction(root
, 0, TRANS_JOIN_NOLOCK
);
348 struct btrfs_trans_handle
*btrfs_start_ioctl_transaction(struct btrfs_root
*root
)
350 return start_transaction(root
, 0, TRANS_USERSPACE
);
353 /* wait for a transaction commit to be fully complete */
354 static noinline
void wait_for_commit(struct btrfs_root
*root
,
355 struct btrfs_transaction
*commit
)
357 wait_event(commit
->commit_wait
, commit
->commit_done
);
360 int btrfs_wait_for_commit(struct btrfs_root
*root
, u64 transid
)
362 struct btrfs_transaction
*cur_trans
= NULL
, *t
;
367 if (transid
<= root
->fs_info
->last_trans_committed
)
370 /* find specified transaction */
371 spin_lock(&root
->fs_info
->trans_lock
);
372 list_for_each_entry(t
, &root
->fs_info
->trans_list
, list
) {
373 if (t
->transid
== transid
) {
375 atomic_inc(&cur_trans
->use_count
);
378 if (t
->transid
> transid
)
381 spin_unlock(&root
->fs_info
->trans_lock
);
384 goto out
; /* bad transid */
386 /* find newest transaction that is committing | committed */
387 spin_lock(&root
->fs_info
->trans_lock
);
388 list_for_each_entry_reverse(t
, &root
->fs_info
->trans_list
,
394 atomic_inc(&cur_trans
->use_count
);
398 spin_unlock(&root
->fs_info
->trans_lock
);
400 goto out
; /* nothing committing|committed */
403 wait_for_commit(root
, cur_trans
);
405 put_transaction(cur_trans
);
411 void btrfs_throttle(struct btrfs_root
*root
)
413 if (!atomic_read(&root
->fs_info
->open_ioctl_trans
))
414 wait_current_trans(root
);
417 static int should_end_transaction(struct btrfs_trans_handle
*trans
,
418 struct btrfs_root
*root
)
421 ret
= btrfs_block_rsv_check(trans
, root
,
422 &root
->fs_info
->global_block_rsv
, 0, 5);
426 int btrfs_should_end_transaction(struct btrfs_trans_handle
*trans
,
427 struct btrfs_root
*root
)
429 struct btrfs_transaction
*cur_trans
= trans
->transaction
;
433 if (cur_trans
->blocked
|| cur_trans
->delayed_refs
.flushing
)
436 updates
= trans
->delayed_ref_updates
;
437 trans
->delayed_ref_updates
= 0;
439 btrfs_run_delayed_refs(trans
, root
, updates
);
441 return should_end_transaction(trans
, root
);
444 static int __btrfs_end_transaction(struct btrfs_trans_handle
*trans
,
445 struct btrfs_root
*root
, int throttle
, int lock
)
447 struct btrfs_transaction
*cur_trans
= trans
->transaction
;
448 struct btrfs_fs_info
*info
= root
->fs_info
;
451 if (--trans
->use_count
) {
452 trans
->block_rsv
= trans
->orig_rsv
;
457 unsigned long cur
= trans
->delayed_ref_updates
;
458 trans
->delayed_ref_updates
= 0;
460 trans
->transaction
->delayed_refs
.num_heads_ready
> 64) {
461 trans
->delayed_ref_updates
= 0;
464 * do a full flush if the transaction is trying
467 if (trans
->transaction
->delayed_refs
.flushing
)
469 btrfs_run_delayed_refs(trans
, root
, cur
);
476 btrfs_trans_release_metadata(trans
, root
);
478 if (lock
&& !atomic_read(&root
->fs_info
->open_ioctl_trans
) &&
479 should_end_transaction(trans
, root
)) {
480 trans
->transaction
->blocked
= 1;
484 if (lock
&& cur_trans
->blocked
&& !cur_trans
->in_commit
) {
487 * We may race with somebody else here so end up having
488 * to call end_transaction on ourselves again, so inc
492 return btrfs_commit_transaction(trans
, root
);
494 wake_up_process(info
->transaction_kthread
);
498 WARN_ON(cur_trans
!= info
->running_transaction
);
499 WARN_ON(atomic_read(&cur_trans
->num_writers
) < 1);
500 atomic_dec(&cur_trans
->num_writers
);
503 if (waitqueue_active(&cur_trans
->writer_wait
))
504 wake_up(&cur_trans
->writer_wait
);
505 put_transaction(cur_trans
);
507 if (current
->journal_info
== trans
)
508 current
->journal_info
= NULL
;
509 memset(trans
, 0, sizeof(*trans
));
510 kmem_cache_free(btrfs_trans_handle_cachep
, trans
);
513 btrfs_run_delayed_iputs(root
);
518 int btrfs_end_transaction(struct btrfs_trans_handle
*trans
,
519 struct btrfs_root
*root
)
523 ret
= __btrfs_end_transaction(trans
, root
, 0, 1);
529 int btrfs_end_transaction_throttle(struct btrfs_trans_handle
*trans
,
530 struct btrfs_root
*root
)
534 ret
= __btrfs_end_transaction(trans
, root
, 1, 1);
540 int btrfs_end_transaction_nolock(struct btrfs_trans_handle
*trans
,
541 struct btrfs_root
*root
)
545 ret
= __btrfs_end_transaction(trans
, root
, 0, 0);
551 int btrfs_end_transaction_dmeta(struct btrfs_trans_handle
*trans
,
552 struct btrfs_root
*root
)
554 return __btrfs_end_transaction(trans
, root
, 1, 1);
558 * when btree blocks are allocated, they have some corresponding bits set for
559 * them in one of two extent_io trees. This is used to make sure all of
560 * those extents are sent to disk but does not wait on them
562 int btrfs_write_marked_extents(struct btrfs_root
*root
,
563 struct extent_io_tree
*dirty_pages
, int mark
)
569 struct inode
*btree_inode
= root
->fs_info
->btree_inode
;
575 ret
= find_first_extent_bit(dirty_pages
, start
, &start
, &end
,
579 while (start
<= end
) {
582 index
= start
>> PAGE_CACHE_SHIFT
;
583 start
= (u64
)(index
+ 1) << PAGE_CACHE_SHIFT
;
584 page
= find_get_page(btree_inode
->i_mapping
, index
);
588 btree_lock_page_hook(page
);
589 if (!page
->mapping
) {
591 page_cache_release(page
);
595 if (PageWriteback(page
)) {
597 wait_on_page_writeback(page
);
600 page_cache_release(page
);
604 err
= write_one_page(page
, 0);
607 page_cache_release(page
);
616 * when btree blocks are allocated, they have some corresponding bits set for
617 * them in one of two extent_io trees. This is used to make sure all of
618 * those extents are on disk for transaction or log commit. We wait
619 * on all the pages and clear them from the dirty pages state tree
621 int btrfs_wait_marked_extents(struct btrfs_root
*root
,
622 struct extent_io_tree
*dirty_pages
, int mark
)
628 struct inode
*btree_inode
= root
->fs_info
->btree_inode
;
634 ret
= find_first_extent_bit(dirty_pages
, start
, &start
, &end
,
639 clear_extent_bits(dirty_pages
, start
, end
, mark
, GFP_NOFS
);
640 while (start
<= end
) {
641 index
= start
>> PAGE_CACHE_SHIFT
;
642 start
= (u64
)(index
+ 1) << PAGE_CACHE_SHIFT
;
643 page
= find_get_page(btree_inode
->i_mapping
, index
);
646 if (PageDirty(page
)) {
647 btree_lock_page_hook(page
);
648 wait_on_page_writeback(page
);
649 err
= write_one_page(page
, 0);
653 wait_on_page_writeback(page
);
654 page_cache_release(page
);
664 * when btree blocks are allocated, they have some corresponding bits set for
665 * them in one of two extent_io trees. This is used to make sure all of
666 * those extents are on disk for transaction or log commit
668 int btrfs_write_and_wait_marked_extents(struct btrfs_root
*root
,
669 struct extent_io_tree
*dirty_pages
, int mark
)
674 ret
= btrfs_write_marked_extents(root
, dirty_pages
, mark
);
675 ret2
= btrfs_wait_marked_extents(root
, dirty_pages
, mark
);
679 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle
*trans
,
680 struct btrfs_root
*root
)
682 if (!trans
|| !trans
->transaction
) {
683 struct inode
*btree_inode
;
684 btree_inode
= root
->fs_info
->btree_inode
;
685 return filemap_write_and_wait(btree_inode
->i_mapping
);
687 return btrfs_write_and_wait_marked_extents(root
,
688 &trans
->transaction
->dirty_pages
,
693 * this is used to update the root pointer in the tree of tree roots.
695 * But, in the case of the extent allocation tree, updating the root
696 * pointer may allocate blocks which may change the root of the extent
699 * So, this loops and repeats and makes sure the cowonly root didn't
700 * change while the root pointer was being updated in the metadata.
702 static int update_cowonly_root(struct btrfs_trans_handle
*trans
,
703 struct btrfs_root
*root
)
708 struct btrfs_root
*tree_root
= root
->fs_info
->tree_root
;
710 old_root_used
= btrfs_root_used(&root
->root_item
);
711 btrfs_write_dirty_block_groups(trans
, root
);
714 old_root_bytenr
= btrfs_root_bytenr(&root
->root_item
);
715 if (old_root_bytenr
== root
->node
->start
&&
716 old_root_used
== btrfs_root_used(&root
->root_item
))
719 btrfs_set_root_node(&root
->root_item
, root
->node
);
720 ret
= btrfs_update_root(trans
, tree_root
,
725 old_root_used
= btrfs_root_used(&root
->root_item
);
726 ret
= btrfs_write_dirty_block_groups(trans
, root
);
730 if (root
!= root
->fs_info
->extent_root
)
731 switch_commit_root(root
);
737 * update all the cowonly tree roots on disk
739 static noinline
int commit_cowonly_roots(struct btrfs_trans_handle
*trans
,
740 struct btrfs_root
*root
)
742 struct btrfs_fs_info
*fs_info
= root
->fs_info
;
743 struct list_head
*next
;
744 struct extent_buffer
*eb
;
747 ret
= btrfs_run_delayed_refs(trans
, root
, (unsigned long)-1);
750 eb
= btrfs_lock_root_node(fs_info
->tree_root
);
751 btrfs_cow_block(trans
, fs_info
->tree_root
, eb
, NULL
, 0, &eb
);
752 btrfs_tree_unlock(eb
);
753 free_extent_buffer(eb
);
755 ret
= btrfs_run_delayed_refs(trans
, root
, (unsigned long)-1);
758 while (!list_empty(&fs_info
->dirty_cowonly_roots
)) {
759 next
= fs_info
->dirty_cowonly_roots
.next
;
761 root
= list_entry(next
, struct btrfs_root
, dirty_list
);
763 update_cowonly_root(trans
, root
);
766 down_write(&fs_info
->extent_commit_sem
);
767 switch_commit_root(fs_info
->extent_root
);
768 up_write(&fs_info
->extent_commit_sem
);
774 * dead roots are old snapshots that need to be deleted. This allocates
775 * a dirty root struct and adds it into the list of dead roots that need to
778 int btrfs_add_dead_root(struct btrfs_root
*root
)
780 spin_lock(&root
->fs_info
->trans_lock
);
781 list_add(&root
->root_list
, &root
->fs_info
->dead_roots
);
782 spin_unlock(&root
->fs_info
->trans_lock
);
787 * update all the cowonly tree roots on disk
789 static noinline
int commit_fs_roots(struct btrfs_trans_handle
*trans
,
790 struct btrfs_root
*root
)
792 struct btrfs_root
*gang
[8];
793 struct btrfs_fs_info
*fs_info
= root
->fs_info
;
798 spin_lock(&fs_info
->fs_roots_radix_lock
);
800 ret
= radix_tree_gang_lookup_tag(&fs_info
->fs_roots_radix
,
803 BTRFS_ROOT_TRANS_TAG
);
806 for (i
= 0; i
< ret
; i
++) {
808 radix_tree_tag_clear(&fs_info
->fs_roots_radix
,
809 (unsigned long)root
->root_key
.objectid
,
810 BTRFS_ROOT_TRANS_TAG
);
811 spin_unlock(&fs_info
->fs_roots_radix_lock
);
813 btrfs_free_log(trans
, root
);
814 btrfs_update_reloc_root(trans
, root
);
815 btrfs_orphan_commit_root(trans
, root
);
817 btrfs_save_ino_cache(root
, trans
);
819 if (root
->commit_root
!= root
->node
) {
820 mutex_lock(&root
->fs_commit_mutex
);
821 switch_commit_root(root
);
822 btrfs_unpin_free_ino(root
);
823 mutex_unlock(&root
->fs_commit_mutex
);
825 btrfs_set_root_node(&root
->root_item
,
829 err
= btrfs_update_root(trans
, fs_info
->tree_root
,
832 spin_lock(&fs_info
->fs_roots_radix_lock
);
837 spin_unlock(&fs_info
->fs_roots_radix_lock
);
842 * defrag a given btree. If cacheonly == 1, this won't read from the disk,
843 * otherwise every leaf in the btree is read and defragged.
845 int btrfs_defrag_root(struct btrfs_root
*root
, int cacheonly
)
847 struct btrfs_fs_info
*info
= root
->fs_info
;
848 struct btrfs_trans_handle
*trans
;
852 if (xchg(&root
->defrag_running
, 1))
856 trans
= btrfs_start_transaction(root
, 0);
858 return PTR_ERR(trans
);
860 ret
= btrfs_defrag_leaves(trans
, root
, cacheonly
);
862 nr
= trans
->blocks_used
;
863 btrfs_end_transaction(trans
, root
);
864 btrfs_btree_balance_dirty(info
->tree_root
, nr
);
867 if (btrfs_fs_closing(root
->fs_info
) || ret
!= -EAGAIN
)
870 root
->defrag_running
= 0;
875 * new snapshots need to be created at a very specific time in the
876 * transaction commit. This does the actual creation
878 static noinline
int create_pending_snapshot(struct btrfs_trans_handle
*trans
,
879 struct btrfs_fs_info
*fs_info
,
880 struct btrfs_pending_snapshot
*pending
)
882 struct btrfs_key key
;
883 struct btrfs_root_item
*new_root_item
;
884 struct btrfs_root
*tree_root
= fs_info
->tree_root
;
885 struct btrfs_root
*root
= pending
->root
;
886 struct btrfs_root
*parent_root
;
887 struct btrfs_block_rsv
*rsv
;
888 struct inode
*parent_inode
;
889 struct dentry
*parent
;
890 struct dentry
*dentry
;
891 struct extent_buffer
*tmp
;
892 struct extent_buffer
*old
;
899 rsv
= trans
->block_rsv
;
901 new_root_item
= kmalloc(sizeof(*new_root_item
), GFP_NOFS
);
902 if (!new_root_item
) {
903 pending
->error
= -ENOMEM
;
907 ret
= btrfs_find_free_objectid(tree_root
, &objectid
);
909 pending
->error
= ret
;
913 btrfs_reloc_pre_snapshot(trans
, pending
, &to_reserve
);
914 btrfs_orphan_pre_snapshot(trans
, pending
, &to_reserve
);
916 if (to_reserve
> 0) {
917 ret
= btrfs_block_rsv_add(trans
, root
, &pending
->block_rsv
,
920 pending
->error
= ret
;
925 key
.objectid
= objectid
;
926 key
.offset
= (u64
)-1;
927 key
.type
= BTRFS_ROOT_ITEM_KEY
;
929 trans
->block_rsv
= &pending
->block_rsv
;
931 dentry
= pending
->dentry
;
932 parent
= dget_parent(dentry
);
933 parent_inode
= parent
->d_inode
;
934 parent_root
= BTRFS_I(parent_inode
)->root
;
935 record_root_in_trans(trans
, parent_root
);
938 * insert the directory item
940 ret
= btrfs_set_inode_index(parent_inode
, &index
);
942 ret
= btrfs_insert_dir_item(trans
, parent_root
,
943 dentry
->d_name
.name
, dentry
->d_name
.len
,
945 BTRFS_FT_DIR
, index
);
948 btrfs_i_size_write(parent_inode
, parent_inode
->i_size
+
949 dentry
->d_name
.len
* 2);
950 ret
= btrfs_update_inode(trans
, parent_root
, parent_inode
);
954 * pull in the delayed directory update
955 * and the delayed inode item
956 * otherwise we corrupt the FS during
959 ret
= btrfs_run_delayed_items(trans
, root
);
962 record_root_in_trans(trans
, root
);
963 btrfs_set_root_last_snapshot(&root
->root_item
, trans
->transid
);
964 memcpy(new_root_item
, &root
->root_item
, sizeof(*new_root_item
));
965 btrfs_check_and_init_root_item(new_root_item
);
967 root_flags
= btrfs_root_flags(new_root_item
);
968 if (pending
->readonly
)
969 root_flags
|= BTRFS_ROOT_SUBVOL_RDONLY
;
971 root_flags
&= ~BTRFS_ROOT_SUBVOL_RDONLY
;
972 btrfs_set_root_flags(new_root_item
, root_flags
);
974 old
= btrfs_lock_root_node(root
);
975 btrfs_cow_block(trans
, root
, old
, NULL
, 0, &old
);
976 btrfs_set_lock_blocking(old
);
978 btrfs_copy_root(trans
, root
, old
, &tmp
, objectid
);
979 btrfs_tree_unlock(old
);
980 free_extent_buffer(old
);
982 btrfs_set_root_node(new_root_item
, tmp
);
983 /* record when the snapshot was created in key.offset */
984 key
.offset
= trans
->transid
;
985 ret
= btrfs_insert_root(trans
, tree_root
, &key
, new_root_item
);
986 btrfs_tree_unlock(tmp
);
987 free_extent_buffer(tmp
);
991 * insert root back/forward references
993 ret
= btrfs_add_root_ref(trans
, tree_root
, objectid
,
994 parent_root
->root_key
.objectid
,
995 btrfs_ino(parent_inode
), index
,
996 dentry
->d_name
.name
, dentry
->d_name
.len
);
1000 key
.offset
= (u64
)-1;
1001 pending
->snap
= btrfs_read_fs_root_no_name(root
->fs_info
, &key
);
1002 BUG_ON(IS_ERR(pending
->snap
));
1004 btrfs_reloc_post_snapshot(trans
, pending
);
1005 btrfs_orphan_post_snapshot(trans
, pending
);
1007 kfree(new_root_item
);
1008 trans
->block_rsv
= rsv
;
1009 btrfs_block_rsv_release(root
, &pending
->block_rsv
, (u64
)-1);
1014 * create all the snapshots we've scheduled for creation
1016 static noinline
int create_pending_snapshots(struct btrfs_trans_handle
*trans
,
1017 struct btrfs_fs_info
*fs_info
)
1019 struct btrfs_pending_snapshot
*pending
;
1020 struct list_head
*head
= &trans
->transaction
->pending_snapshots
;
1023 list_for_each_entry(pending
, head
, list
) {
1024 ret
= create_pending_snapshot(trans
, fs_info
, pending
);
1030 static void update_super_roots(struct btrfs_root
*root
)
1032 struct btrfs_root_item
*root_item
;
1033 struct btrfs_super_block
*super
;
1035 super
= &root
->fs_info
->super_copy
;
1037 root_item
= &root
->fs_info
->chunk_root
->root_item
;
1038 super
->chunk_root
= root_item
->bytenr
;
1039 super
->chunk_root_generation
= root_item
->generation
;
1040 super
->chunk_root_level
= root_item
->level
;
1042 root_item
= &root
->fs_info
->tree_root
->root_item
;
1043 super
->root
= root_item
->bytenr
;
1044 super
->generation
= root_item
->generation
;
1045 super
->root_level
= root_item
->level
;
1046 if (super
->cache_generation
!= 0 || btrfs_test_opt(root
, SPACE_CACHE
))
1047 super
->cache_generation
= root_item
->generation
;
1050 int btrfs_transaction_in_commit(struct btrfs_fs_info
*info
)
1053 spin_lock(&info
->trans_lock
);
1054 if (info
->running_transaction
)
1055 ret
= info
->running_transaction
->in_commit
;
1056 spin_unlock(&info
->trans_lock
);
1060 int btrfs_transaction_blocked(struct btrfs_fs_info
*info
)
1063 spin_lock(&info
->trans_lock
);
1064 if (info
->running_transaction
)
1065 ret
= info
->running_transaction
->blocked
;
1066 spin_unlock(&info
->trans_lock
);
1071 * wait for the current transaction commit to start and block subsequent
1074 static void wait_current_trans_commit_start(struct btrfs_root
*root
,
1075 struct btrfs_transaction
*trans
)
1077 wait_event(root
->fs_info
->transaction_blocked_wait
, trans
->in_commit
);
1081 * wait for the current transaction to start and then become unblocked.
1084 static void wait_current_trans_commit_start_and_unblock(struct btrfs_root
*root
,
1085 struct btrfs_transaction
*trans
)
1087 wait_event(root
->fs_info
->transaction_wait
,
1088 trans
->commit_done
|| (trans
->in_commit
&& !trans
->blocked
));
1092 * commit transactions asynchronously. once btrfs_commit_transaction_async
1093 * returns, any subsequent transaction will not be allowed to join.
1095 struct btrfs_async_commit
{
1096 struct btrfs_trans_handle
*newtrans
;
1097 struct btrfs_root
*root
;
1098 struct delayed_work work
;
1101 static void do_async_commit(struct work_struct
*work
)
1103 struct btrfs_async_commit
*ac
=
1104 container_of(work
, struct btrfs_async_commit
, work
.work
);
1106 btrfs_commit_transaction(ac
->newtrans
, ac
->root
);
1110 int btrfs_commit_transaction_async(struct btrfs_trans_handle
*trans
,
1111 struct btrfs_root
*root
,
1112 int wait_for_unblock
)
1114 struct btrfs_async_commit
*ac
;
1115 struct btrfs_transaction
*cur_trans
;
1117 ac
= kmalloc(sizeof(*ac
), GFP_NOFS
);
1121 INIT_DELAYED_WORK(&ac
->work
, do_async_commit
);
1123 ac
->newtrans
= btrfs_join_transaction(root
);
1124 if (IS_ERR(ac
->newtrans
)) {
1125 int err
= PTR_ERR(ac
->newtrans
);
1130 /* take transaction reference */
1131 cur_trans
= trans
->transaction
;
1132 atomic_inc(&cur_trans
->use_count
);
1134 btrfs_end_transaction(trans
, root
);
1135 schedule_delayed_work(&ac
->work
, 0);
1137 /* wait for transaction to start and unblock */
1138 if (wait_for_unblock
)
1139 wait_current_trans_commit_start_and_unblock(root
, cur_trans
);
1141 wait_current_trans_commit_start(root
, cur_trans
);
1143 if (current
->journal_info
== trans
)
1144 current
->journal_info
= NULL
;
1146 put_transaction(cur_trans
);
1151 * btrfs_transaction state sequence:
1152 * in_commit = 0, blocked = 0 (initial)
1153 * in_commit = 1, blocked = 1
1157 int btrfs_commit_transaction(struct btrfs_trans_handle
*trans
,
1158 struct btrfs_root
*root
)
1160 unsigned long joined
= 0;
1161 struct btrfs_transaction
*cur_trans
;
1162 struct btrfs_transaction
*prev_trans
= NULL
;
1165 int should_grow
= 0;
1166 unsigned long now
= get_seconds();
1167 int flush_on_commit
= btrfs_test_opt(root
, FLUSHONCOMMIT
);
1169 btrfs_run_ordered_operations(root
, 0);
1171 /* make a pass through all the delayed refs we have so far
1172 * any runnings procs may add more while we are here
1174 ret
= btrfs_run_delayed_refs(trans
, root
, 0);
1177 btrfs_trans_release_metadata(trans
, root
);
1179 cur_trans
= trans
->transaction
;
1181 * set the flushing flag so procs in this transaction have to
1182 * start sending their work down.
1184 cur_trans
->delayed_refs
.flushing
= 1;
1186 ret
= btrfs_run_delayed_refs(trans
, root
, 0);
1189 spin_lock(&cur_trans
->commit_lock
);
1190 if (cur_trans
->in_commit
) {
1191 spin_unlock(&cur_trans
->commit_lock
);
1192 atomic_inc(&cur_trans
->use_count
);
1193 btrfs_end_transaction(trans
, root
);
1195 wait_for_commit(root
, cur_trans
);
1197 put_transaction(cur_trans
);
1202 trans
->transaction
->in_commit
= 1;
1203 trans
->transaction
->blocked
= 1;
1204 spin_unlock(&cur_trans
->commit_lock
);
1205 wake_up(&root
->fs_info
->transaction_blocked_wait
);
1207 spin_lock(&root
->fs_info
->trans_lock
);
1208 if (cur_trans
->list
.prev
!= &root
->fs_info
->trans_list
) {
1209 prev_trans
= list_entry(cur_trans
->list
.prev
,
1210 struct btrfs_transaction
, list
);
1211 if (!prev_trans
->commit_done
) {
1212 atomic_inc(&prev_trans
->use_count
);
1213 spin_unlock(&root
->fs_info
->trans_lock
);
1215 wait_for_commit(root
, prev_trans
);
1217 put_transaction(prev_trans
);
1219 spin_unlock(&root
->fs_info
->trans_lock
);
1222 spin_unlock(&root
->fs_info
->trans_lock
);
1225 if (now
< cur_trans
->start_time
|| now
- cur_trans
->start_time
< 1)
1229 int snap_pending
= 0;
1231 joined
= cur_trans
->num_joined
;
1232 if (!list_empty(&trans
->transaction
->pending_snapshots
))
1235 WARN_ON(cur_trans
!= trans
->transaction
);
1237 if (flush_on_commit
|| snap_pending
) {
1238 btrfs_start_delalloc_inodes(root
, 1);
1239 ret
= btrfs_wait_ordered_extents(root
, 0, 1);
1243 ret
= btrfs_run_delayed_items(trans
, root
);
1247 * rename don't use btrfs_join_transaction, so, once we
1248 * set the transaction to blocked above, we aren't going
1249 * to get any new ordered operations. We can safely run
1250 * it here and no for sure that nothing new will be added
1253 btrfs_run_ordered_operations(root
, 1);
1255 prepare_to_wait(&cur_trans
->writer_wait
, &wait
,
1256 TASK_UNINTERRUPTIBLE
);
1258 if (atomic_read(&cur_trans
->num_writers
) > 1)
1259 schedule_timeout(MAX_SCHEDULE_TIMEOUT
);
1260 else if (should_grow
)
1261 schedule_timeout(1);
1263 finish_wait(&cur_trans
->writer_wait
, &wait
);
1264 } while (atomic_read(&cur_trans
->num_writers
) > 1 ||
1265 (should_grow
&& cur_trans
->num_joined
!= joined
));
1268 * Ok now we need to make sure to block out any other joins while we
1269 * commit the transaction. We could have started a join before setting
1270 * no_join so make sure to wait for num_writers to == 1 again.
1272 spin_lock(&root
->fs_info
->trans_lock
);
1273 root
->fs_info
->trans_no_join
= 1;
1274 spin_unlock(&root
->fs_info
->trans_lock
);
1275 wait_event(cur_trans
->writer_wait
,
1276 atomic_read(&cur_trans
->num_writers
) == 1);
1279 * the reloc mutex makes sure that we stop
1280 * the balancing code from coming in and moving
1281 * extents around in the middle of the commit
1283 mutex_lock(&root
->fs_info
->reloc_mutex
);
1285 ret
= btrfs_run_delayed_items(trans
, root
);
1288 ret
= create_pending_snapshots(trans
, root
->fs_info
);
1291 ret
= btrfs_run_delayed_refs(trans
, root
, (unsigned long)-1);
1295 * make sure none of the code above managed to slip in a
1298 btrfs_assert_delayed_root_empty(root
);
1300 WARN_ON(cur_trans
!= trans
->transaction
);
1302 btrfs_scrub_pause(root
);
1303 /* btrfs_commit_tree_roots is responsible for getting the
1304 * various roots consistent with each other. Every pointer
1305 * in the tree of tree roots has to point to the most up to date
1306 * root for every subvolume and other tree. So, we have to keep
1307 * the tree logging code from jumping in and changing any
1310 * At this point in the commit, there can't be any tree-log
1311 * writers, but a little lower down we drop the trans mutex
1312 * and let new people in. By holding the tree_log_mutex
1313 * from now until after the super is written, we avoid races
1314 * with the tree-log code.
1316 mutex_lock(&root
->fs_info
->tree_log_mutex
);
1318 ret
= commit_fs_roots(trans
, root
);
1321 /* commit_fs_roots gets rid of all the tree log roots, it is now
1322 * safe to free the root of tree log roots
1324 btrfs_free_log_root_tree(trans
, root
->fs_info
);
1326 ret
= commit_cowonly_roots(trans
, root
);
1329 btrfs_prepare_extent_commit(trans
, root
);
1331 cur_trans
= root
->fs_info
->running_transaction
;
1333 btrfs_set_root_node(&root
->fs_info
->tree_root
->root_item
,
1334 root
->fs_info
->tree_root
->node
);
1335 switch_commit_root(root
->fs_info
->tree_root
);
1337 btrfs_set_root_node(&root
->fs_info
->chunk_root
->root_item
,
1338 root
->fs_info
->chunk_root
->node
);
1339 switch_commit_root(root
->fs_info
->chunk_root
);
1341 update_super_roots(root
);
1343 if (!root
->fs_info
->log_root_recovering
) {
1344 btrfs_set_super_log_root(&root
->fs_info
->super_copy
, 0);
1345 btrfs_set_super_log_root_level(&root
->fs_info
->super_copy
, 0);
1348 memcpy(&root
->fs_info
->super_for_commit
, &root
->fs_info
->super_copy
,
1349 sizeof(root
->fs_info
->super_copy
));
1351 trans
->transaction
->blocked
= 0;
1352 spin_lock(&root
->fs_info
->trans_lock
);
1353 root
->fs_info
->running_transaction
= NULL
;
1354 root
->fs_info
->trans_no_join
= 0;
1355 spin_unlock(&root
->fs_info
->trans_lock
);
1356 mutex_unlock(&root
->fs_info
->reloc_mutex
);
1358 wake_up(&root
->fs_info
->transaction_wait
);
1360 ret
= btrfs_write_and_wait_transaction(trans
, root
);
1362 write_ctree_super(trans
, root
, 0);
1365 * the super is written, we can safely allow the tree-loggers
1366 * to go about their business
1368 mutex_unlock(&root
->fs_info
->tree_log_mutex
);
1370 btrfs_finish_extent_commit(trans
, root
);
1372 cur_trans
->commit_done
= 1;
1374 root
->fs_info
->last_trans_committed
= cur_trans
->transid
;
1376 wake_up(&cur_trans
->commit_wait
);
1378 spin_lock(&root
->fs_info
->trans_lock
);
1379 list_del_init(&cur_trans
->list
);
1380 spin_unlock(&root
->fs_info
->trans_lock
);
1382 put_transaction(cur_trans
);
1383 put_transaction(cur_trans
);
1385 trace_btrfs_transaction_commit(root
);
1387 btrfs_scrub_continue(root
);
1389 if (current
->journal_info
== trans
)
1390 current
->journal_info
= NULL
;
1392 kmem_cache_free(btrfs_trans_handle_cachep
, trans
);
1394 if (current
!= root
->fs_info
->transaction_kthread
)
1395 btrfs_run_delayed_iputs(root
);
1401 * interface function to delete all the snapshots we have scheduled for deletion
1403 int btrfs_clean_old_snapshots(struct btrfs_root
*root
)
1406 struct btrfs_fs_info
*fs_info
= root
->fs_info
;
1408 spin_lock(&fs_info
->trans_lock
);
1409 list_splice_init(&fs_info
->dead_roots
, &list
);
1410 spin_unlock(&fs_info
->trans_lock
);
1412 while (!list_empty(&list
)) {
1413 root
= list_entry(list
.next
, struct btrfs_root
, root_list
);
1414 list_del(&root
->root_list
);
1416 btrfs_kill_all_delayed_nodes(root
);
1418 if (btrfs_header_backref_rev(root
->node
) <
1419 BTRFS_MIXED_BACKREF_REV
)
1420 btrfs_drop_snapshot(root
, NULL
, 0);
1422 btrfs_drop_snapshot(root
, NULL
, 1);