a4abeea41a
We use trans_mutex for lots of things, here's a basic list 1) To serialize trans_handles joining the currently running transaction 2) To make sure that no new trans handles are started while we are committing 3) To protect the dead_roots list and the transaction lists Really the serializing trans_handles joining is not too hard, and can really get bogged down in acquiring a reference to the transaction. So replace the trans_mutex with a trans_lock spinlock and use it to do the following 1) Protect fs_info->running_transaction. All trans handles have to do is check this, and then take a reference of the transaction and keep on going. 2) Protect the fs_info->trans_list. This doesn't get used too much, basically it just holds the current transactions, which will usually just be the currently committing transaction and the currently running transaction at most. 3) Protect the dead roots list. This is only ever processed by splicing the list so this is relatively simple. 4) Protect the fs_info->reloc_ctl stuff. This is very lightweight and was using the trans_mutex before, so this is a pretty straightforward change. 5) Protect fs_info->no_trans_join. Because we don't hold the trans_lock over the entirety of the commit we need to have a way to block new people from creating a new transaction while we're doing our work. So we set no_trans_join and in join_transaction we test to see if that is set, and if it is we do a wait_on_commit. 6) Make the transaction use count atomic so we don't need to take locks to modify it when we're dropping references. 7) Add a commit_lock to the transaction to make sure multiple people trying to commit the same transaction don't race and commit at the same time. 8) Make open_ioctl_trans an atomic so we don't have to take any locks for ioctl trans. I have tested this with xfstests, but obviously it is a pretty hairy change so lots of testing is greatly appreciated. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
132 lines
4.5 KiB
C
132 lines
4.5 KiB
C
/*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#ifndef __BTRFS_TRANSACTION__
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#define __BTRFS_TRANSACTION__
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#include "btrfs_inode.h"
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#include "delayed-ref.h"
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struct btrfs_transaction {
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u64 transid;
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/*
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* total writers in this transaction, it must be zero before the
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* transaction can end
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*/
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atomic_t num_writers;
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atomic_t use_count;
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unsigned long num_joined;
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spinlock_t commit_lock;
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int in_commit;
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int commit_done;
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int blocked;
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struct list_head list;
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struct extent_io_tree dirty_pages;
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unsigned long start_time;
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wait_queue_head_t writer_wait;
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wait_queue_head_t commit_wait;
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struct list_head pending_snapshots;
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struct btrfs_delayed_ref_root delayed_refs;
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};
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struct btrfs_trans_handle {
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u64 transid;
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u64 block_group;
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u64 bytes_reserved;
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unsigned long use_count;
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unsigned long blocks_reserved;
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unsigned long blocks_used;
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unsigned long delayed_ref_updates;
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struct btrfs_transaction *transaction;
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struct btrfs_block_rsv *block_rsv;
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struct btrfs_block_rsv *orig_rsv;
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};
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struct btrfs_pending_snapshot {
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struct dentry *dentry;
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struct btrfs_root *root;
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struct btrfs_root *snap;
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/* block reservation for the operation */
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struct btrfs_block_rsv block_rsv;
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/* extra metadata reseration for relocation */
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int error;
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bool readonly;
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struct list_head list;
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};
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static inline void btrfs_set_trans_block_group(struct btrfs_trans_handle *trans,
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struct inode *inode)
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{
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trans->block_group = BTRFS_I(inode)->block_group;
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}
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static inline void btrfs_update_inode_block_group(
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struct btrfs_trans_handle *trans,
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struct inode *inode)
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{
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BTRFS_I(inode)->block_group = trans->block_group;
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}
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static inline void btrfs_set_inode_last_trans(struct btrfs_trans_handle *trans,
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struct inode *inode)
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{
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BTRFS_I(inode)->last_trans = trans->transaction->transid;
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BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
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}
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int btrfs_end_transaction(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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int btrfs_end_transaction_nolock(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
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int num_items);
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struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root);
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struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root);
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struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root);
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int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid);
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int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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int btrfs_add_dead_root(struct btrfs_root *root);
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int btrfs_drop_dead_root(struct btrfs_root *root);
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int btrfs_defrag_root(struct btrfs_root *root, int cacheonly);
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int btrfs_clean_old_snapshots(struct btrfs_root *root);
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int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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int wait_for_unblock);
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int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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int btrfs_should_end_transaction(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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void btrfs_throttle(struct btrfs_root *root);
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int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
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struct extent_io_tree *dirty_pages, int mark);
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int btrfs_write_marked_extents(struct btrfs_root *root,
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struct extent_io_tree *dirty_pages, int mark);
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int btrfs_wait_marked_extents(struct btrfs_root *root,
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struct extent_io_tree *dirty_pages, int mark);
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int btrfs_transaction_blocked(struct btrfs_fs_info *info);
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int btrfs_transaction_in_commit(struct btrfs_fs_info *info);
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#endif
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