/*
* Copyright (C) 2007 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/writeback.h>
#include <linux/pagemap.h>
#include <linux/blkdev.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "locking.h"
#include "ref-cache.h"
#include "tree-log.h"
static int total_trans = 0;
extern struct kmem_cache *btrfs_trans_handle_cachep;
extern struct kmem_cache *btrfs_transaction_cachep;
#define BTRFS_ROOT_TRANS_TAG 0
static noinline void put_transaction(struct btrfs_transaction *transaction)
{
WARN_ON(transaction->use_count == 0);
transaction->use_count--;
if (transaction->use_count == 0) {
WARN_ON(total_trans == 0);
total_trans--;
list_del_init(&transaction->list);
memset(transaction, 0, sizeof(*transaction));
kmem_cache_free(btrfs_transaction_cachep, transaction);
}
}
/*
* either allocate a new transaction or hop into the existing one
*/
static noinline int join_transaction(struct btrfs_root *root)
{
struct btrfs_transaction *cur_trans;
cur_trans = root->fs_info->running_transaction;
if (!cur_trans) {
cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
GFP_NOFS);
total_trans++;
BUG_ON(!cur_trans);
root->fs_info->generation++;
root->fs_info->last_alloc = 0;
root->fs_info->last_data_alloc = 0;
cur_trans->num_writers = 1;
cur_trans->num_joined = 0;
cur_trans->transid = root->fs_info->generation;
init_waitqueue_head(&cur_trans->writer_wait);
init_waitqueue_head(&cur_trans->commit_wait);
cur_trans->in_commit = 0;
cur_trans->blocked = 0;
cur_trans->use_count = 1;
cur_trans->commit_done = 0;
cur_trans->start_time = get_seconds();
INIT_LIST_HEAD(&cur_trans->pending_snapshots);
list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
extent_io_tree_init(&cur_trans->dirty_pages,
root->fs_info->btree_inode->i_mapping,
GFP_NOFS);
spin_lock(&root->fs_info->new_trans_lock);
root->fs_info->running_transaction = cur_trans;
spin_unlock(&root->fs_info->new_trans_lock);
} else {
cur_trans->num_writers++;
cur_trans->num_joined++;
}
return 0;
}
/*
* this does all the record keeping required to make sure that a
* reference counted root is properly recorded in a given transaction.
* This is required to make sure the old root from before we joined the transaction
* is deleted when the transaction commits
*/
noinline int btrfs_record_root_in_trans(struct btrfs_root *root)
{
struct btrfs_dirty_root *dirty;
u64 running_trans_id = root->fs_info->running_transaction->transid;
if (root->ref_cows && root->last_trans < running_trans_id) {
WARN_ON(root == root->fs_info->extent_root);
if (root->root_item.refs != 0) {
radix_tree_tag_set(&root->fs_info->fs_roots_radix,
(unsigned long)root->root_key.objectid,
BTRFS_ROOT_TRANS_TAG);
dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
BUG_ON(!dirty);
dirty->root = kmalloc(sizeof(*dirty->root), GFP_NOFS);
BUG_ON(!dirty->root);
dirty->latest_root = root;
INIT_LIST_HEAD(&dirty->list);
root->commit_root = btrfs_root_node(root);
memcpy(dirty->root, root, sizeof(*root));
spin_lock_init(&dirty->root->node_lock);
spin_lock_init(&dirty->root->list_lock);
mutex_init(&dirty->root->objectid_mutex);
mutex_init(&dirty->root->log_mutex);
INIT_LIST_HEAD(&dirty->root->dead_list);
dirty->root->node = root->commit_root;
dirty->root->commit_root = NULL;
spin_lock(&root->list_lock);
list_add(&dirty->root->dead_list, &root->dead_list);
spin_unlock(&root->list_lock);
root->dirty_root = dirty;
} else {
WARN_ON(1);
}
root->last_trans = running_trans_id;
}
return 0;
}
/* wait for commit against the current transaction to become unblocked
* when this is done, it is safe to start a new transaction, but the current
* transaction might not be fully on disk.
*/
static void wait_current_trans(struct btrfs_root *root)
{
struct btrfs_transaction *cur_trans;
cur_trans = root->fs_info->running_transaction;
if (cur_trans && cur_trans->blocked) {
DEFINE_WAIT(wait);
cur_trans->use_count++;
while(1) {
prepare_to_wait(&root->fs_info->transaction_wait, &wait,
TASK_UNINTERRUPTIBLE);
if (cur_trans->blocked) {
mutex_unlock(&root->fs_info->trans_mutex);
schedule();
mutex_lock(&root->fs_info->trans_mutex);
finish_wait(&root->fs_info->transaction_wait,
&wait);
} else {
finish_wait(&root->fs_info->transaction_wait,
&wait);
break;
}
}
put_transaction(cur_trans);
}
}
static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
int num_blocks, int wait)
{
struct btrfs_trans_handle *h =
kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
int ret;
mutex_lock(&root->fs_info->trans_mutex);
if (!root->fs_info->log_root_recovering &&
((wait == 1 && !root->fs_info->open_ioctl_trans) || wait == 2))
wait_current_trans(root);
ret = join_transaction(root);
BUG_ON(ret);
btrfs_record_root_in_trans(root);
h->transid = root->fs_info->running_transaction->transid;
h->transaction = root->fs_info->running_transaction;
h->blocks_reserved = num_blocks;
h->blocks_used = 0;
h->block_group = NULL;
h->alloc_exclude_nr = 0;
h->alloc_exclude_start = 0;
root->fs_info->running_transaction->use_count++;
mutex_unlock(&root->fs_info->trans_mutex);
return h;
}
struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
int num_blocks)
{
return start_transaction(root, num_blocks, 1);
}
struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root,
int num_blocks)
{
return start_transaction(root, num_blocks, 0);
}
struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r,
int num_blocks)
{
return start_transaction(r, num_blocks, 2);
}
/* wait for a transaction commit to be fully complete */
static noinline int wait_for_commit(struct btrfs_root *root,
struct btrfs_transaction *commit)
{
DEFINE_WAIT(wait);
mutex_lock(&root->fs_info->trans_mutex);
while(!commit->commit_done) {
prepare_to_wait(&commit->commit_wait, &wait,
TASK_UNINTERRUPTIBLE);
if (commit->commit_done)
break;
mutex_unlock(&root->fs_info->trans_mutex);
schedule();
mutex_lock(&root->fs_info->trans_mutex);
}
mutex_unlock(&root->fs_info->trans_mutex);
finish_wait(&commit->commit_wait, &wait);
return 0;
}
/*
* rate limit against the drop_snapshot code. This helps to slow down new operations
* if the drop_snapshot code isn't able to keep up.
*/
static void throttle_on_drops(struct btrfs_root *root)
{
struct btrfs_fs_info *info = root->fs_info;
int harder_count = 0;
harder:
if (atomic_read(&info->throttles)) {
DEFINE_WAIT(wait);
int thr;
thr = atomic_read(&info->throttle_gen);
do {
prepare_to_wait(&info->transaction_throttle,
&wait, TASK_UNINTERRUPTIBLE);
if (!atomic_read(&info->throttles)) {
finish_wait(&info->transaction_throttle, &wait);
break;
}
schedule();
finish_wait(&info->transaction_throttle, &wait);
} while (thr == atomic_read(&info->throttle_gen));
harder_count++;
if (root->fs_info->total_ref_cache_size > 1 * 1024 * 1024 &&
harder_count < 2)
goto harder;
if (root->fs_info->total_ref_cache_size > 5 * 1024 * 1024 &&
harder_count < 10)
goto harder;
if (root->fs_info->total_ref_cache_size > 10 * 1024 * 1024 &&
harder_count < 20)
goto harder;
}
}
void btrfs_throttle(struct btrfs_root *root)
{
mutex_lock(&root->fs_info->trans_mutex);
if (!root->fs_info->open_ioctl_trans)
wait_current_trans(root);
mutex_unlock(&root->fs_info->trans_mutex);
throttle_on_drops(root);
}
static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root, int throttle)
{
struct btrfs_transaction *cur_trans;
struct btrfs_fs_info *info = root->fs_info;
mutex_lock(&info->trans_mutex);
cur_trans = info->running_transaction;
WARN_ON(cur_trans != trans->transaction);
WARN_ON(cur_trans->num_writers < 1);
cur_trans->num_writers--;
if (waitqueue_active(&cur_trans->writer_wait))
wake_up(&cur_trans->writer_wait);
put_transaction(cur_trans);
mutex_unlock(&info->trans_mutex);
memset(trans, 0, sizeof(*trans));
kmem_cache_free(btrfs_trans_handle_cachep, trans);
if (throttle)
throttle_on_drops(root);
return 0;
}
int btrfs_end_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
return __btrfs_end_transaction(trans, root, 0);
}
int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
return __btrfs_end_transaction(trans, root, 1);
}
/*
* when btree blocks are allocated, they have some corresponding bits set for
* them in one of two extent_io trees. This is used to make sure all of
* those extents are on disk for transaction or log commit
*/
int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
struct extent_io_tree *dirty_pages)
{
int ret;
int err = 0;
int werr = 0;
struct page *page;
struct inode *btree_inode = root->fs_info->btree_inode;
struct extent_io_tree *io_tree = &BTRFS_I(btree_inode)->io_tree;
u64 start = 0;
u64 end;
unsigned long index;
while(1) {
ret = find_first_extent_bit(dirty_pages, start, &start, &end,
EXTENT_DIRTY);
if (ret)
break;
while(start <= end) {
cond_resched();
index = start >> PAGE_CACHE_SHIFT;
start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
page = find_get_page(btree_inode->i_mapping, index);
if (!page)
continue;
btree_lock_page_hook(page);
if (!page->mapping) {
unlock_page(page);
page_cache_release(page);
continue;
}
if (PageWriteback(page)) {
if (PageDirty(page))
wait_on_page_writeback(page);
else {
unlock_page(page);
page_cache_release(page);
continue;
}
}
err = write_one_page(page, 0);
if (err)
werr = err;
page_cache_release(page);
}
}
/*
* we unplug once and then use the wait_on_extent_bit for
* everything else
*/
blk_run_address_space(btree_inode->i_mapping);
while(1) {
ret = find_first_extent_bit(dirty_pages, 0, &start, &end,
EXTENT_DIRTY);
if (ret)
break;
clear_extent_dirty(dirty_pages, start, end, GFP_NOFS);
while(start <= end) {
index = start >> PAGE_CACHE_SHIFT;
start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
page = find_get_page(btree_inode->i_mapping, index);
if (!page)
continue;
if (PageDirty(page)) {
btree_lock_page_hook(page);
wait_on_page_writeback(page);
err = write_one_page(page, 0);
if (err)
werr = err;
}
if (PageWriteback(page)) {
/*
* we don't wait on the page writeback bit
* because that triggers a lot of unplugs.
* The extent bits are much nicer to
* the disks, but come with a slightly
* higher latency because we aren't forcing
* unplugs.
*/
wait_on_extent_writeback(io_tree,
page_offset(page),
page_offset(page) +
PAGE_CACHE_SIZE - 1);
}
if (PageWriteback(page)) {
/*
* the state bits get cleared before the
* page bits, lets add some extra
* paranoia here
*/
wait_on_page_writeback(page);
}
page_cache_release(page);
cond_resched();
}
}
if (err)
werr = err;
return werr;
}
int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
if (!trans || !trans->transaction) {
struct inode *btree_inode;
btree_inode = root->fs_info->btree_inode;
return filemap_write_and_wait(btree_inode->i_mapping);
}
return btrfs_write_and_wait_marked_extents(root,
&trans->transaction->dirty_pages);
}
/*
* this is used to update the root pointer in the tree of tree roots.
*
* But, in the case of the extent allocation tree, updating the root
* pointer may allocate blocks which may change the root of the extent
* allocation tree.
*
* So, this loops and repeats and makes sure the cowonly root didn't
* change while the root pointer was being updated in the metadata.
*/
static int update_cowonly_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
int ret;
u64 old_root_bytenr;
struct btrfs_root *tree_root = root->fs_info->tree_root;
btrfs_extent_post_op(trans, root);
btrfs_write_dirty_block_groups(trans, root);
btrfs_extent_post_op(trans, root);
while(1) {
old_root_bytenr = btrfs_root_bytenr(&root->root_item);
if (old_root_bytenr == root->node->start)
break;
btrfs_set_root_bytenr(&root->root_item,
root->node->start);
btrfs_set_root_level(&root->root_item,
btrfs_header_level(root->node));
btrfs_set_root_generation(&root->root_item, trans->transid);
btrfs_extent_post_op(trans, root);
ret = btrfs_update_root(trans, tree_root,
&root->root_key,
&root->root_item);
BUG_ON(ret);
btrfs_write_dirty_block_groups(trans, root);
btrfs_extent_post_op(trans, root);
}
return 0;
}
/*
* update all the cowonly tree roots on disk
*/
int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct list_head *next;
struct extent_buffer *eb;
btrfs_extent_post_op(trans, fs_info->tree_root);
eb = btrfs_lock_root_node(fs_info->tree_root);
btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb, 0);
btrfs_tree_unlock(eb);
free_extent_buffer(eb);
btrfs_extent_post_op(trans, fs_info->tree_root);
while(!list_empty(&fs_info->dirty_cowonly_roots)) {
next = fs_info->dirty_cowonly_roots.next;
list_del_init(next);
root = list_entry(next, struct btrfs_root, dirty_list);
update_cowonly_root(trans, root);
}
return 0;
}
/*
* dead roots are old snapshots that need to be deleted. This allocates
* a dirty root struct and adds it into the list of dead roots that need to
* be deleted
*/
int btrfs_add_dead_root(struct btrfs_root *root, struct btrfs_root *latest)
{
struct btrfs_dirty_root *dirty;
dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
if (!dirty)
return -ENOMEM;
dirty->root = root;
dirty->latest_root = latest;
mutex_lock(&root->fs_info->trans_mutex);
list_add(&dirty->list, &latest->fs_info->dead_roots);
mutex_unlock(&root->fs_info->trans_mutex);
return 0;
}
/*
* at transaction commit time we need to schedule the old roots for
* deletion via btrfs_drop_snapshot. This runs through all the
* reference counted roots that were modified in the current
* transaction and puts them into the drop list
*/
static noinline int add_dirty_roots(struct btrfs_trans_handle *trans,
struct radix_tree_root *radix,
struct list_head *list)
{
struct btrfs_dirty_root *dirty;
struct btrfs_root *gang[8];
struct btrfs_root *root;
int i;
int ret;
int err = 0;
u32 refs;
while(1) {
ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
ARRAY_SIZE(gang),
BTRFS_ROOT_TRANS_TAG);
if (ret == 0)
break;
for (i = 0; i < ret; i++) {
root = gang[i];
radix_tree_tag_clear(radix,
(unsigned long)root->root_key.objectid,
BTRFS_ROOT_TRANS_TAG);
BUG_ON(!root->ref_tree);
dirty = root->dirty_root;
btrfs_free_log(trans, root);
btrfs_free_reloc_root(trans, root);
if (root->commit_root == root->node) {
WARN_ON(root->node->start !=
btrfs_root_bytenr(&root->root_item));
free_extent_buffer(root->commit_root);
root->commit_root = NULL;
root->dirty_root = NULL;
spin_lock(&root->list_lock);
list_del_init(&dirty->root->dead_list);
spin_unlock(&root->list_lock);
kfree(dirty->root);
kfree(dirty);
/* make sure to update the root on disk
* so we get any updates to the block used
* counts
*/
err = btrfs_update_root(trans,
root->fs_info->tree_root,
&root->root_key,
&root->root_item);
continue;
}
memset(&root->root_item.drop_progress, 0,
sizeof(struct btrfs_disk_key));
root->root_item.drop_level = 0;
root->commit_root = NULL;
root->dirty_root = NULL;
root->root_key.offset = root->fs_info->generation;
btrfs_set_root_bytenr(&root->root_item,
root->node->start);
btrfs_set_root_level(&root->root_item,
btrfs_header_level(root->node));
btrfs_set_root_generation(&root->root_item,
root->root_key.offset);
err = btrfs_insert_root(trans, root->fs_info->tree_root,
&root->root_key,
&root->root_item);
if (err)
break;
refs = btrfs_root_refs(&dirty->root->root_item);
btrfs_set_root_refs(&dirty->root->root_item, refs - 1);
err = btrfs_update_root(trans, root->fs_info->tree_root,
&dirty->root->root_key,
&dirty->root->root_item);
BUG_ON(err);
if (refs == 1) {
list_add(&dirty->list, list);
} else {
WARN_ON(1);
free_extent_buffer(dirty->root->node);
kfree(dirty->root);
kfree(dirty);
}
}
}
return err;
}
/*
* defrag a given btree. If cacheonly == 1, this won't read from the disk,
* otherwise every leaf in the btree is read and defragged.
*/
int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
{
struct btrfs_fs_info *info = root->fs_info;
int ret;
struct btrfs_trans_handle *trans;
unsigned long nr;
smp_mb();
if (root->defrag_running)
return 0;
trans = btrfs_start_transaction(root, 1);
while (1) {
root->defrag_running = 1;
ret = btrfs_defrag_leaves(trans, root, cacheonly);
nr = trans->blocks_used;
btrfs_end_transaction(trans, root);
btrfs_btree_balance_dirty(info->tree_root, nr);
cond_resched();
trans = btrfs_start_transaction(root, 1);
if (root->fs_info->closing || ret != -EAGAIN)
break;
}
root->defrag_running = 0;
smp_mb();
btrfs_end_transaction(trans, root);
return 0;
}
/*
* Given a list of roots that need to be deleted, call btrfs_drop_snapshot on
* all of them
*/
static noinline int drop_dirty_roots(struct btrfs_root *tree_root,
struct list_head *list)
{
struct btrfs_dirty_root *dirty;
struct btrfs_trans_handle *trans;
unsigned long nr;
u64 num_bytes;
u64 bytes_used;
u64 max_useless;
int ret = 0;
int err;
while(!list_empty(list)) {
struct btrfs_root *root;
dirty = list_entry(list->prev, struct btrfs_dirty_root, list);
list_del_init(&dirty->list);
num_bytes = btrfs_root_used(&dirty->root->root_item);
root = dirty->latest_root;
atomic_inc(&root->fs_info->throttles);
while(1) {
trans = btrfs_start_transaction(tree_root, 1);
mutex_lock(&root->fs_info->drop_mutex);
ret = btrfs_drop_snapshot(trans, dirty->root);
if (ret != -EAGAIN) {
break;
}
mutex_unlock(&root->fs_info->drop_mutex);
err = btrfs_update_root(trans,
tree_root,
&dirty->root->root_key,
&dirty->root->root_item);
if (err)
ret = err;
nr = trans->blocks_used;
ret = btrfs_end_transaction(trans, tree_root);
BUG_ON(ret);
btrfs_btree_balance_dirty(tree_root, nr);
cond_resched();
}
BUG_ON(ret);
atomic_dec(&root->fs_info->throttles);
wake_up(&root->fs_info->transaction_throttle);
num_bytes -= btrfs_root_used(&dirty->root->root_item);
bytes_used = btrfs_root_used(&root->root_item);
if (num_bytes) {
btrfs_record_root_in_trans(root);
btrfs_set_root_used(&root->root_item,
bytes_used - num_bytes);
}
ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key);
if (ret) {
BUG();
break;
}
mutex_unlock(&root->fs_info->drop_mutex);
spin_lock(&root->list_lock);
list_del_init(&dirty->root->dead_list);
if (!list_empty(&root->dead_list)) {
struct btrfs_root *oldest;
oldest = list_entry(root->dead_list.prev,
struct btrfs_root, dead_list);
max_useless = oldest->root_key.offset - 1;
} else {
max_useless = root->root_key.offset - 1;
}
spin_unlock(&root->list_lock);
nr = trans->blocks_used;
ret = btrfs_end_transaction(trans, tree_root);
BUG_ON(ret);
ret = btrfs_remove_leaf_refs(root, max_useless, 0);
BUG_ON(ret);
free_extent_buffer(dirty->root->node);
kfree(dirty->root);
kfree(dirty);
btrfs_btree_balance_dirty(tree_root, nr);
cond_resched();
}
return ret;
}
/*
* new snapshots need to be created at a very specific time in the
* transaction commit. This does the actual creation
*/
static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
struct btrfs_pending_snapshot *pending)
{
struct btrfs_key key;
struct btrfs_root_item *new_root_item;
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_root *root = pending->root;
struct extent_buffer *tmp;
struct extent_buffer *old;
int ret;
int namelen;
u64 objectid;
new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
if (!new_root_item) {
ret = -ENOMEM;
goto fail;
}
ret = btrfs_find_free_objectid(trans, tree_root, 0, &objectid);
if (ret)
goto fail;
btrfs_record_root_in_trans(root);
btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
key.objectid = objectid;
key.offset = trans->transid;
btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
old = btrfs_lock_root_node(root);
btrfs_cow_block(trans, root, old, NULL, 0, &old, 0);
btrfs_copy_root(trans, root, old, &tmp, objectid);
btrfs_tree_unlock(old);
free_extent_buffer(old);
btrfs_set_root_bytenr(new_root_item, tmp->start);
btrfs_set_root_level(new_root_item, btrfs_header_level(tmp));
btrfs_set_root_generation(new_root_item, trans->transid);
ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
new_root_item);
btrfs_tree_unlock(tmp);
free_extent_buffer(tmp);
if (ret)
goto fail;
/*
* insert the directory item
*/
key.offset = (u64)-1;
namelen = strlen(pending->name);
ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
pending->name, namelen,
root->fs_info->sb->s_root->d_inode->i_ino,
&key, BTRFS_FT_DIR, 0);
if (ret)
goto fail;
ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,
pending->name, strlen(pending->name), objectid,
root->fs_info->sb->s_root->d_inode->i_ino, 0);
/* Invalidate existing dcache entry for new snapshot. */
btrfs_invalidate_dcache_root(root, pending->name, namelen);
fail:
kfree(new_root_item);
return ret;
}
/*
* create all the snapshots we've scheduled for creation
*/
static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info)
{
struct btrfs_pending_snapshot *pending;
struct list_head *head = &trans->transaction->pending_snapshots;
int ret;
while(!list_empty(head)) {
pending = list_entry(head->next,
struct btrfs_pending_snapshot, list);
ret = create_pending_snapshot(trans, fs_info, pending);
BUG_ON(ret);
list_del(&pending->list);
kfree(pending->name);
kfree(pending);
}
return 0;
}
int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
unsigned long joined = 0;
unsigned long timeout = 1;
struct btrfs_transaction *cur_trans;
struct btrfs_transaction *prev_trans = NULL;
struct btrfs_root *chunk_root = root->fs_info->chunk_root;
struct list_head dirty_fs_roots;
struct extent_io_tree *pinned_copy;
DEFINE_WAIT(wait);
int ret;
INIT_LIST_HEAD(&dirty_fs_roots);
mutex_lock(&root->fs_info->trans_mutex);
if (trans->transaction->in_commit) {
cur_trans = trans->transaction;
trans->transaction->use_count++;
mutex_unlock(&root->fs_info->trans_mutex);
btrfs_end_transaction(trans, root);
ret = wait_for_commit(root, cur_trans);
BUG_ON(ret);
mutex_lock(&root->fs_info->trans_mutex);
put_transaction(cur_trans);
mutex_unlock(&root->fs_info->trans_mutex);
return 0;
}
pinned_copy = kmalloc(sizeof(*pinned_copy), GFP_NOFS);
if (!pinned_copy)
return -ENOMEM;
extent_io_tree_init(pinned_copy,
root->fs_info->btree_inode->i_mapping, GFP_NOFS);
trans->transaction->in_commit = 1;
trans->transaction->blocked = 1;
cur_trans = trans->transaction;
if (cur_trans->list.prev != &root->fs_info->trans_list) {
prev_trans = list_entry(cur_trans->list.prev,
struct btrfs_transaction, list);
if (!prev_trans->commit_done) {
prev_trans->use_count++;
mutex_unlock(&root->fs_info->trans_mutex);
wait_for_commit(root, prev_trans);
mutex_lock(&root->fs_info->trans_mutex);
put_transaction(prev_trans);
}
}
do {
int snap_pending = 0;
joined = cur_trans->num_joined;
if (!list_empty(&trans->transaction->pending_snapshots))
snap_pending = 1;
WARN_ON(cur_trans != trans->transaction);
prepare_to_wait(&cur_trans->writer_wait, &wait,
TASK_UNINTERRUPTIBLE);
if (cur_trans->num_writers > 1)
timeout = MAX_SCHEDULE_TIMEOUT;
else
timeout = 1;
mutex_unlock(&root->fs_info->trans_mutex);
if (snap_pending) {
ret = btrfs_wait_ordered_extents(root, 1);
BUG_ON(ret);
}
schedule_timeout(timeout);
mutex_lock(&root->fs_info->trans_mutex);
finish_wait(&cur_trans->writer_wait, &wait);
} while (cur_trans->num_writers > 1 ||
(cur_trans->num_joined != joined));
ret = create_pending_snapshots(trans, root->fs_info);
BUG_ON(ret);
WARN_ON(cur_trans != trans->transaction);
/* btrfs_commit_tree_roots is responsible for getting the
* various roots consistent with each other. Every pointer
* in the tree of tree roots has to point to the most up to date
* root for every subvolume and other tree. So, we have to keep
* the tree logging code from jumping in and changing any
* of the trees.
*
* At this point in the commit, there can't be any tree-log
* writers, but a little lower down we drop the trans mutex
* and let new people in. By holding the tree_log_mutex
* from now until after the super is written, we avoid races
* with the tree-log code.
*/
mutex_lock(&root->fs_info->tree_log_mutex);
/*
* keep tree reloc code from adding new reloc trees
*/
mutex_lock(&root->fs_info->tree_reloc_mutex);
ret = add_dirty_roots(trans, &root->fs_info->fs_roots_radix,
&dirty_fs_roots);
BUG_ON(ret);
/* add_dirty_roots gets rid of all the tree log roots, it is now
* safe to free the root of tree log roots
*/
btrfs_free_log_root_tree(trans, root->fs_info);
ret = btrfs_commit_tree_roots(trans, root);
BUG_ON(ret);
cur_trans = root->fs_info->running_transaction;
spin_lock(&root->fs_info->new_trans_lock);
root->fs_info->running_transaction = NULL;
spin_unlock(&root->fs_info->new_trans_lock);
btrfs_set_super_generation(&root->fs_info->super_copy,
cur_trans->transid);
btrfs_set_super_root(&root->fs_info->super_copy,
root->fs_info->tree_root->node->start);
btrfs_set_super_root_level(&root->fs_info->super_copy,
btrfs_header_level(root->fs_info->tree_root->node));
btrfs_set_super_chunk_root(&root->fs_info->super_copy,
chunk_root->node->start);
btrfs_set_super_chunk_root_level(&root->fs_info->super_copy,
btrfs_header_level(chunk_root->node));
btrfs_set_super_chunk_root_generation(&root->fs_info->super_copy,
btrfs_header_generation(chunk_root->node));
if (!root->fs_info->log_root_recovering) {
btrfs_set_super_log_root(&root->fs_info->super_copy, 0);
btrfs_set_super_log_root_level(&root->fs_info->super_copy, 0);
}
memcpy(&root->fs_info->super_for_commit, &root->fs_info->super_copy,
sizeof(root->fs_info->super_copy));
btrfs_copy_pinned(root, pinned_copy);
trans->transaction->blocked = 0;
wake_up(&root->fs_info->transaction_throttle);
wake_up(&root->fs_info->transaction_wait);
mutex_unlock(&root->fs_info->trans_mutex);
ret = btrfs_write_and_wait_transaction(trans, root);
BUG_ON(ret);
write_ctree_super(trans, root);
/*
* the super is written, we can safely allow the tree-loggers
* to go about their business
*/
mutex_unlock(&root->fs_info->tree_log_mutex);
btrfs_finish_extent_commit(trans, root, pinned_copy);
kfree(pinned_copy);
btrfs_drop_dead_reloc_roots(root);
mutex_unlock(&root->fs_info->tree_reloc_mutex);
mutex_lock(&root->fs_info->trans_mutex);
cur_trans->commit_done = 1;
root->fs_info->last_trans_committed = cur_trans->transid;
wake_up(&cur_trans->commit_wait);
put_transaction(cur_trans);
put_transaction(cur_trans);
list_splice_init(&dirty_fs_roots, &root->fs_info->dead_roots);
if (root->fs_info->closing)
list_splice_init(&root->fs_info->dead_roots, &dirty_fs_roots);
mutex_unlock(&root->fs_info->trans_mutex);
kmem_cache_free(btrfs_trans_handle_cachep, trans);
if (root->fs_info->closing) {
drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
}
return ret;
}
/*
* interface function to delete all the snapshots we have scheduled for deletion
*/
int btrfs_clean_old_snapshots(struct btrfs_root *root)
{
struct list_head dirty_roots;
INIT_LIST_HEAD(&dirty_roots);
again:
mutex_lock(&root->fs_info->trans_mutex);
list_splice_init(&root->fs_info->dead_roots, &dirty_roots);
mutex_unlock(&root->fs_info->trans_mutex);
if (!list_empty(&dirty_roots)) {
drop_dirty_roots(root, &dirty_roots);
goto again;
}
return 0;
}
