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OpenCloudOS-Kernel/fs/btrfs/transaction.h

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Btrfs: add GPLv2 Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-06-12 21:07:21 +08:00
/*
* 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.
*/
Btrfs: Add data=ordered support This forces file data extents down the disk along with the metadata that references them. The current implementation is fairly simple, and just writes out all of the dirty pages in an inode before the commit. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-01-09 04:46:30 +08:00
#ifndef __BTRFS_TRANSACTION__
#define __BTRFS_TRANSACTION__
Btrfs: allocator improvements, inode block groups Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-05-01 03:25:45 +08:00
#include "btrfs_inode.h"
Btrfs: do extent allocation and reference count updates in the background The extent allocation tree maintains a reference count and full back reference information for every extent allocated in the filesystem. For subvolume and snapshot trees, every time a block goes through COW, the new copy of the block adds a reference on every block it points to. If a btree node points to 150 leaves, then the COW code needs to go and add backrefs on 150 different extents, which might be spread all over the extent allocation tree. These updates currently happen during btrfs_cow_block, and most COWs happen during btrfs_search_slot. btrfs_search_slot has locks held on both the parent and the node we are COWing, and so we really want to avoid IO during the COW if we can. This commit adds an rbtree of pending reference count updates and extent allocations. The tree is ordered by byte number of the extent and byte number of the parent for the back reference. The tree allows us to: 1) Modify back references in something close to disk order, reducing seeks 2) Significantly reduce the number of modifications made as block pointers are balanced around 3) Do all of the extent insertion and back reference modifications outside of the performance critical btrfs_search_slot code. #3 has the added benefit of greatly reducing the btrfs stack footprint. The extent allocation tree modifications are done without the deep (and somewhat recursive) call chains used in the past. These delayed back reference updates must be done before the transaction commits, and so the rbtree is tied to the transaction. Throttling is implemented to help keep the queue of backrefs at a reasonable size. Since there was a similar mechanism in place for the extent tree extents, that is removed and replaced by the delayed reference tree. Yan Zheng <yan.zheng@oracle.com> helped review and fixup this code. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-03-13 22:10:06 +08:00
#include "delayed-ref.h"
Btrfs: qgroup implementation and prototypes Signed-off-by: Arne Jansen <sensille@gmx.net> Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-06-29 00:03:02 +08:00
#include "ctree.h"
Btrfs: transaction handles everywhere Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-03-17 04:20:31 +08:00
Btrfs: make the state of the transaction more readable We used 3 variants to track the state of the transaction, it was complex and wasted the memory space. Besides that, it was hard to understand that which types of the transaction handles should be blocked in each transaction state, so the developers often made mistakes. This patch improved the above problem. In this patch, we define 6 states for the transaction, enum btrfs_trans_state { TRANS_STATE_RUNNING = 0, TRANS_STATE_BLOCKED = 1, TRANS_STATE_COMMIT_START = 2, TRANS_STATE_COMMIT_DOING = 3, TRANS_STATE_UNBLOCKED = 4, TRANS_STATE_COMPLETED = 5, TRANS_STATE_MAX = 6, } and just use 1 variant to track those state. In order to make the blocked handle types for each state more clear, we introduce a array: unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = { [TRANS_STATE_RUNNING] = 0U, [TRANS_STATE_BLOCKED] = (__TRANS_USERSPACE | __TRANS_START), [TRANS_STATE_COMMIT_START] = (__TRANS_USERSPACE | __TRANS_START | __TRANS_ATTACH), [TRANS_STATE_COMMIT_DOING] = (__TRANS_USERSPACE | __TRANS_START | __TRANS_ATTACH | __TRANS_JOIN), [TRANS_STATE_UNBLOCKED] = (__TRANS_USERSPACE | __TRANS_START | __TRANS_ATTACH | __TRANS_JOIN | __TRANS_JOIN_NOLOCK), [TRANS_STATE_COMPLETED] = (__TRANS_USERSPACE | __TRANS_START | __TRANS_ATTACH | __TRANS_JOIN | __TRANS_JOIN_NOLOCK), } it is very intuitionistic. Besides that, because we remove ->in_commit in transaction structure, so the lock ->commit_lock which was used to protect it is unnecessary, remove ->commit_lock. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-05-17 11:53:43 +08:00
enum btrfs_trans_state {
TRANS_STATE_RUNNING = 0,
TRANS_STATE_BLOCKED = 1,
TRANS_STATE_COMMIT_START = 2,
TRANS_STATE_COMMIT_DOING = 3,
TRANS_STATE_UNBLOCKED = 4,
TRANS_STATE_COMPLETED = 5,
TRANS_STATE_MAX = 6,
};
Btrfs: transaction rework Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-03-23 03:59:16 +08:00
struct btrfs_transaction {
u64 transid;
Btrfs: don't wait for all the writers circularly during the transaction commit btrfs_commit_transaction has the following loop before we commit the transaction. do { // attempt to do some useful stuff and/or sleep } while (atomic_read(&cur_trans->num_writers) > 1 || (should_grow && cur_trans->num_joined != joined)); This is used to prevent from the TRANS_START to get in the way of a committing transaction. But it does not prevent from TRANS_JOIN, that is we would do this loop for a long time if some writers JOIN the current transaction endlessly. Because we need join the current transaction to do some useful stuff, we can not block TRANS_JOIN here. So we introduce a external writer counter, which is used to count the TRANS_USERSPACE/TRANS_START writers. If the external writer counter is zero, we can break the above loop. In order to make the code more clear, we don't use enum variant to define the type of the transaction handle, use bitmask instead. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-05-15 15:48:27 +08:00
/*
* total external writers(USERSPACE/START/ATTACH) in this
* transaction, it must be zero before the transaction is
* being committed
*/
atomic_t num_extwriters;
Btrfs: reduce stalls during transaction commit To avoid deadlocks and reduce latencies during some critical operations, some transaction writers are allowed to jump into the running transaction and make it run a little longer, while others sit around and wait for the commit to finish. This is a bit unfair, especially when the callers that jump in do a bunch of IO that makes all the others procs on the box wait. This commit reduces the stalls this produces by pre-reading file extent pointers during btrfs_finish_ordered_io before the transaction is joined. It also tunes the drop_snapshot code to politely wait for transactions that have started writing out their delayed refs to finish. This avoids new delayed refs being flooded into the queue while we're trying to close off the transaction. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-03-13 08:12:45 +08:00
/*
* total writers in this transaction, it must be zero before the
* transaction can end
*/
Btrfs: avoid taking the trans_mutex in btrfs_end_transaction I've been working on making our O_DIRECT latency not suck and I noticed we were taking the trans_mutex in btrfs_end_transaction. So to do this we convert num_writers and use_count to atomic_t's and just decrement them in btrfs_end_transaction. Instead of deleting the transaction from the trans list in put_transaction we do that in btrfs_commit_transaction() since that's the only time it actually needs to be removed from the list. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2011-04-12 03:45:29 +08:00
atomic_t num_writers;
Btrfs: kill trans_mutex 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>
2011-04-12 05:25:13 +08:00
atomic_t use_count;
Btrfs: reduce stalls during transaction commit To avoid deadlocks and reduce latencies during some critical operations, some transaction writers are allowed to jump into the running transaction and make it run a little longer, while others sit around and wait for the commit to finish. This is a bit unfair, especially when the callers that jump in do a bunch of IO that makes all the others procs on the box wait. This commit reduces the stalls this produces by pre-reading file extent pointers during btrfs_finish_ordered_io before the transaction is joined. It also tunes the drop_snapshot code to politely wait for transactions that have started writing out their delayed refs to finish. This avoids new delayed refs being flooded into the queue while we're trying to close off the transaction. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-03-13 08:12:45 +08:00
Btrfs: make the state of the transaction more readable We used 3 variants to track the state of the transaction, it was complex and wasted the memory space. Besides that, it was hard to understand that which types of the transaction handles should be blocked in each transaction state, so the developers often made mistakes. This patch improved the above problem. In this patch, we define 6 states for the transaction, enum btrfs_trans_state { TRANS_STATE_RUNNING = 0, TRANS_STATE_BLOCKED = 1, TRANS_STATE_COMMIT_START = 2, TRANS_STATE_COMMIT_DOING = 3, TRANS_STATE_UNBLOCKED = 4, TRANS_STATE_COMPLETED = 5, TRANS_STATE_MAX = 6, } and just use 1 variant to track those state. In order to make the blocked handle types for each state more clear, we introduce a array: unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = { [TRANS_STATE_RUNNING] = 0U, [TRANS_STATE_BLOCKED] = (__TRANS_USERSPACE | __TRANS_START), [TRANS_STATE_COMMIT_START] = (__TRANS_USERSPACE | __TRANS_START | __TRANS_ATTACH), [TRANS_STATE_COMMIT_DOING] = (__TRANS_USERSPACE | __TRANS_START | __TRANS_ATTACH | __TRANS_JOIN), [TRANS_STATE_UNBLOCKED] = (__TRANS_USERSPACE | __TRANS_START | __TRANS_ATTACH | __TRANS_JOIN | __TRANS_JOIN_NOLOCK), [TRANS_STATE_COMPLETED] = (__TRANS_USERSPACE | __TRANS_START | __TRANS_ATTACH | __TRANS_JOIN | __TRANS_JOIN_NOLOCK), } it is very intuitionistic. Besides that, because we remove ->in_commit in transaction structure, so the lock ->commit_lock which was used to protect it is unnecessary, remove ->commit_lock. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-05-17 11:53:43 +08:00
/* Be protected by fs_info->trans_lock when we want to change it. */
enum btrfs_trans_state state;
Btrfs: early fsync support Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-04-20 09:01:03 +08:00
struct list_head list;
Btrfs: Split the extent_map code into two parts There is now extent_map for mapping offsets in the file to disk and extent_io for state tracking, IO submission and extent_bufers. The new extent_map code shifts from [start,end] pairs to [start,len], and pushes the locking out into the caller. This allows a few performance optimizations and is easier to use. A number of extent_map usage bugs were fixed, mostly with failing to remove extent_map entries when changing the file. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-01-25 05:13:08 +08:00
struct extent_io_tree dirty_pages;
Btrfs: add compat ioctl Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-06-09 03:33:54 +08:00
unsigned long start_time;
Btrfs: transaction rework Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-03-23 03:59:16 +08:00
wait_queue_head_t writer_wait;
wait_queue_head_t commit_wait;
Btrfs: Move snapshot creation to commit time It is very difficult to create a consistent snapshot of the btree when other writers may update the btree before the commit is done. This changes the snapshot creation to happen during the commit, while no other updates are possible. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-01-09 04:46:30 +08:00
struct list_head pending_snapshots;
Btrfs: place ordered operations on a per transaction list Miao made the ordered operations stuff run async, which introduced a deadlock where we could get somebody (sync) racing in and committing the transaction while a commit was already happening. The new committer would try and flush ordered operations which would hang waiting for the commit to finish because it is done asynchronously and no longer inherits the callers trans handle. To fix this we need to make the ordered operations list a per transaction list. We can get new inodes added to the ordered operation list by truncating them and then having another process writing to them, so this makes it so that anybody trying to add an ordered operation _must_ start a transaction in order to add itself to the list, which will keep new inodes from getting added to the ordered operations list after we start committing. This should fix the deadlock and also keeps us from doing a lot more work than we need to during commit. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-14 00:09:14 +08:00
struct list_head ordered_operations;
Btrfs: make the chunk allocator completely tree lockless When adjusting the enospc rules for relocation I ran into a deadlock because we were relocating the only system chunk and that forced us to try and allocate a new system chunk while holding locks in the chunk tree, which caused us to deadlock. To fix this I've moved all of the dev extent addition and chunk addition out to the delayed chunk completion stuff. We still keep the in-memory stuff which makes sure everything is consistent. One change I had to make was to search the commit root of the device tree to find a free dev extent, and hold onto any chunk em's that we allocated in that transaction so we do not allocate the same dev extent twice. This has the side effect of fixing a bug with balance that has been there ever since balance existed. Basically you can free a block group and it's dev extent and then immediately allocate that dev extent for a new block group and write stuff to that dev extent, all within the same transaction. So if you happen to crash during a balance you could come back to a completely broken file system. This patch should keep these sort of things from happening in the future since we won't be able to allocate free'd dev extents until after the transaction commits. This has passed all of the xfstests and my super annoying stress test followed by a balance. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-06-28 01:22:46 +08:00
struct list_head pending_chunks;
Btrfs: do extent allocation and reference count updates in the background The extent allocation tree maintains a reference count and full back reference information for every extent allocated in the filesystem. For subvolume and snapshot trees, every time a block goes through COW, the new copy of the block adds a reference on every block it points to. If a btree node points to 150 leaves, then the COW code needs to go and add backrefs on 150 different extents, which might be spread all over the extent allocation tree. These updates currently happen during btrfs_cow_block, and most COWs happen during btrfs_search_slot. btrfs_search_slot has locks held on both the parent and the node we are COWing, and so we really want to avoid IO during the COW if we can. This commit adds an rbtree of pending reference count updates and extent allocations. The tree is ordered by byte number of the extent and byte number of the parent for the back reference. The tree allows us to: 1) Modify back references in something close to disk order, reducing seeks 2) Significantly reduce the number of modifications made as block pointers are balanced around 3) Do all of the extent insertion and back reference modifications outside of the performance critical btrfs_search_slot code. #3 has the added benefit of greatly reducing the btrfs stack footprint. The extent allocation tree modifications are done without the deep (and somewhat recursive) call chains used in the past. These delayed back reference updates must be done before the transaction commits, and so the rbtree is tied to the transaction. Throttling is implemented to help keep the queue of backrefs at a reasonable size. Since there was a similar mechanism in place for the extent tree extents, that is removed and replaced by the delayed reference tree. Yan Zheng <yan.zheng@oracle.com> helped review and fixup this code. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-03-13 22:10:06 +08:00
struct btrfs_delayed_ref_root delayed_refs;
btrfs: enhance transaction abort infrastructure Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-02 00:24:58 +08:00
int aborted;
Btrfs: transaction rework Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-03-23 03:59:16 +08:00
};
Btrfs: don't wait for all the writers circularly during the transaction commit btrfs_commit_transaction has the following loop before we commit the transaction. do { // attempt to do some useful stuff and/or sleep } while (atomic_read(&cur_trans->num_writers) > 1 || (should_grow && cur_trans->num_joined != joined)); This is used to prevent from the TRANS_START to get in the way of a committing transaction. But it does not prevent from TRANS_JOIN, that is we would do this loop for a long time if some writers JOIN the current transaction endlessly. Because we need join the current transaction to do some useful stuff, we can not block TRANS_JOIN here. So we introduce a external writer counter, which is used to count the TRANS_USERSPACE/TRANS_START writers. If the external writer counter is zero, we can break the above loop. In order to make the code more clear, we don't use enum variant to define the type of the transaction handle, use bitmask instead. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-05-15 15:48:27 +08:00
#define __TRANS_FREEZABLE (1U << 0)
#define __TRANS_USERSPACE (1U << 8)
#define __TRANS_START (1U << 9)
#define __TRANS_ATTACH (1U << 10)
#define __TRANS_JOIN (1U << 11)
#define __TRANS_JOIN_NOLOCK (1U << 12)
#define TRANS_USERSPACE (__TRANS_USERSPACE | __TRANS_FREEZABLE)
#define TRANS_START (__TRANS_START | __TRANS_FREEZABLE)
#define TRANS_ATTACH (__TRANS_ATTACH)
#define TRANS_JOIN (__TRANS_JOIN | __TRANS_FREEZABLE)
#define TRANS_JOIN_NOLOCK (__TRANS_JOIN_NOLOCK)
#define TRANS_EXTWRITERS (__TRANS_USERSPACE | __TRANS_START | \
__TRANS_ATTACH)
Btrfs: add a type field for the transaction handle This patch add a type field into the transaction handle structure, in this way, we needn't implement various end-transaction functions and can make the code more simple and readable. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
2012-09-20 15:51:59 +08:00
Btrfs: transaction handles everywhere Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-03-17 04:20:31 +08:00
struct btrfs_trans_handle {
u64 transid;
Btrfs: Introduce contexts for metadata reservation Introducing metadata reseravtion contexts has two major advantages. First, it makes metadata reseravtion more traceable. Second, it can reclaim freed space and re-add them to the itself after transaction committed. Besides add btrfs_block_rsv structure and related helper functions, This patch contains following changes: Move code that decides if freed tree block should be pinned into btrfs_free_tree_block(). Make space accounting more accurate, mainly for handling read only block groups. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-05-16 22:46:25 +08:00
u64 bytes_reserved;
Btrfs: hooks to reserve qgroup space Like block reserves, reserve a small piece of space on each transaction start and for delalloc. These are the hooks that can actually return EDQUOT to the user. The amount of space reserved is tracked in the transaction handle. Signed-off-by: Arne Jansen <sensille@gmx.net>
2011-09-14 21:44:05 +08:00
u64 qgroup_reserved;
Btrfs: if we've already started a trans handle, use that one We currently track trans handles in current->journal_info, but we don't actually use it. This patch fixes it. This will cover the case where we have multiple people starting transactions down the call chain. This keeps us from having to allocate a new handle and all of that, we just increase the use count of the current handle, save the old block_rsv, and return. I tested this with xfstests and it worked out fine. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2011-04-14 03:15:59 +08:00
unsigned long use_count;
Btrfs: transaction handles everywhere Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-03-17 04:20:31 +08:00
unsigned long blocks_reserved;
unsigned long blocks_used;
Btrfs: do extent allocation and reference count updates in the background The extent allocation tree maintains a reference count and full back reference information for every extent allocated in the filesystem. For subvolume and snapshot trees, every time a block goes through COW, the new copy of the block adds a reference on every block it points to. If a btree node points to 150 leaves, then the COW code needs to go and add backrefs on 150 different extents, which might be spread all over the extent allocation tree. These updates currently happen during btrfs_cow_block, and most COWs happen during btrfs_search_slot. btrfs_search_slot has locks held on both the parent and the node we are COWing, and so we really want to avoid IO during the COW if we can. This commit adds an rbtree of pending reference count updates and extent allocations. The tree is ordered by byte number of the extent and byte number of the parent for the back reference. The tree allows us to: 1) Modify back references in something close to disk order, reducing seeks 2) Significantly reduce the number of modifications made as block pointers are balanced around 3) Do all of the extent insertion and back reference modifications outside of the performance critical btrfs_search_slot code. #3 has the added benefit of greatly reducing the btrfs stack footprint. The extent allocation tree modifications are done without the deep (and somewhat recursive) call chains used in the past. These delayed back reference updates must be done before the transaction commits, and so the rbtree is tied to the transaction. Throttling is implemented to help keep the queue of backrefs at a reasonable size. Since there was a similar mechanism in place for the extent tree extents, that is removed and replaced by the delayed reference tree. Yan Zheng <yan.zheng@oracle.com> helped review and fixup this code. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-03-13 22:10:06 +08:00
unsigned long delayed_ref_updates;
Btrfs: Introduce contexts for metadata reservation Introducing metadata reseravtion contexts has two major advantages. First, it makes metadata reseravtion more traceable. Second, it can reclaim freed space and re-add them to the itself after transaction committed. Besides add btrfs_block_rsv structure and related helper functions, This patch contains following changes: Move code that decides if freed tree block should be pinned into btrfs_free_tree_block(). Make space accounting more accurate, mainly for handling read only block groups. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-05-16 22:46:25 +08:00
struct btrfs_transaction *transaction;
struct btrfs_block_rsv *block_rsv;
Btrfs: if we've already started a trans handle, use that one We currently track trans handles in current->journal_info, but we don't actually use it. This patch fixes it. This will cover the case where we have multiple people starting transactions down the call chain. This keeps us from having to allocate a new handle and all of that, we just increase the use count of the current handle, save the old block_rsv, and return. I tested this with xfstests and it worked out fine. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2011-04-14 03:15:59 +08:00
struct btrfs_block_rsv *orig_rsv;
Btrfs: add a type field for the transaction handle This patch add a type field into the transaction handle structure, in this way, we needn't implement various end-transaction functions and can make the code more simple and readable. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
2012-09-20 15:51:59 +08:00
short aborted;
short adding_csums;
Btrfs: don't re-enter when allocating a chunk If we start running low on metadata space we will try to allocate a chunk, which could then try to allocate a chunk to add the device entry. The thing is we allocate a chunk before we try really hard to make the allocation, so we should be able to find space for the device entry. Add a flag to the trans handle so we know we're currently allocating a chunk so we can just bail out if we try to allocate another chunk. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-12-18 22:16:16 +08:00
bool allocating_chunk;
Btrfs: don't wait for all the writers circularly during the transaction commit btrfs_commit_transaction has the following loop before we commit the transaction. do { // attempt to do some useful stuff and/or sleep } while (atomic_read(&cur_trans->num_writers) > 1 || (should_grow && cur_trans->num_joined != joined)); This is used to prevent from the TRANS_START to get in the way of a committing transaction. But it does not prevent from TRANS_JOIN, that is we would do this loop for a long time if some writers JOIN the current transaction endlessly. Because we need join the current transaction to do some useful stuff, we can not block TRANS_JOIN here. So we introduce a external writer counter, which is used to count the TRANS_USERSPACE/TRANS_START writers. If the external writer counter is zero, we can break the above loop. In order to make the code more clear, we don't use enum variant to define the type of the transaction handle, use bitmask instead. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-05-15 15:48:27 +08:00
unsigned int type;
Btrfs: check the root passed to btrfs_end_transaction This patch only add a consistancy check to validate that the same root is passed to start_transaction and end_transaction. Subvolume quota depends on this. Signed-off-by: Arne Jansen <sensille@gmx.net>
2011-09-13 17:40:09 +08:00
/*
* this root is only needed to validate that the root passed to
* start_transaction is the same as the one passed to end_transaction.
* Subvolume quota depends on this
*/
struct btrfs_root *root;
Btrfs: qgroup implementation and prototypes Signed-off-by: Arne Jansen <sensille@gmx.net> Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-06-29 00:03:02 +08:00
struct seq_list delayed_ref_elem;
struct list_head qgroup_ref_list;
Btrfs: delay block group item insertion So we have lots of places where we try to preallocate chunks in order to make sure we have enough space as we make our allocations. This has historically meant that we're constantly tweaking when we should allocate a new chunk, and historically we have gotten this horribly wrong so we way over allocate either metadata or data. To try and keep this from happening we are going to make it so that the block group item insertion is done out of band at the end of a transaction. This will allow us to create chunks even if we are trying to make an allocation for the extent tree. With this patch my enospc tests run faster (didn't expect this) and more efficiently use the disk space (this is what I wanted). Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-09-12 04:57:25 +08:00
struct list_head new_bgs;
Btrfs: transaction handles everywhere Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-03-17 04:20:31 +08:00
};
Btrfs: Move snapshot creation to commit time It is very difficult to create a consistent snapshot of the btree when other writers may update the btree before the commit is done. This changes the snapshot creation to happen during the commit, while no other updates are possible. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-01-09 04:46:30 +08:00
struct btrfs_pending_snapshot {
Btrfs: Allow subvolumes and snapshots anywhere in the directory tree Before, all snapshots and subvolumes lived in a single flat directory. This was awkward and confusing because the single flat directory was only writable with the ioctls. This commit changes the ioctls to create subvols and snapshots at any point in the directory tree. This requires making separate ioctls for snapshot and subvol creation instead of a combining them into one. The subvol ioctl does: btrfsctl -S subvol_name parent_dir After the ioctl is done subvol_name lives inside parent_dir. The snapshot ioctl does: btrfsctl -s path_for_snapshot root_to_snapshot path_for_snapshot can be an absolute or relative path. btrfsctl breaks it up into directory and basename components. root_to_snapshot can be any file or directory in the FS. The snapshot is taken of the entire root where that file lives. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-11-18 10:02:50 +08:00
struct dentry *dentry;
Btrfs: remove unnecessary dget_parent/dput when creating the pending snapshot Since we have grabbed the parent inode at the beginning of the snapshot creation, and both sync and async snapshot creation release it after the pending snapshots are actually created, it is safe to access the parent inode directly during the snapshot creation, we needn't use dget_parent/dput to fix the parent dentry and get the dir inode. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-28 18:01:15 +08:00
struct inode *dir;
Btrfs: Move snapshot creation to commit time It is very difficult to create a consistent snapshot of the btree when other writers may update the btree before the commit is done. This changes the snapshot creation to happen during the commit, while no other updates are possible. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-01-09 04:46:30 +08:00
struct btrfs_root *root;
Btrfs: Integrate metadata reservation with start_transaction Besides simplify the code, this change makes sure all metadata reservation for normal metadata operations are released after committing transaction. Changes since V1: Add code that check if unlink and rmdir will free space. Add ENOSPC handling for clone ioctl. Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-05-16 22:48:46 +08:00
struct btrfs_root *snap;
Btrfs: add qgroup inheritance When creating a subvolume or snapshot, it is necessary to initialize the qgroup account with a copy of some other (tracking) qgroup. This patch adds parameters to the ioctls to pass the information from which qgroup to inherit. Signed-off-by: Arne Jansen <sensille@gmx.net>
2011-09-14 21:58:21 +08:00
struct btrfs_qgroup_inherit *inherit;
Btrfs: Integrate metadata reservation with start_transaction Besides simplify the code, this change makes sure all metadata reservation for normal metadata operations are released after committing transaction. Changes since V1: Add code that check if unlink and rmdir will free space. Add ENOSPC handling for clone ioctl. Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-05-16 22:48:46 +08:00
/* block reservation for the operation */
struct btrfs_block_rsv block_rsv;
Btrfs: fix wrong reserved space in qgroup during snap/subv creation There are two problems in the space reservation of the snapshot/ subvolume creation. - don't reserve the space for the root item insertion - the space which is reserved in the qgroup is different with the free space reservation. we need reserve free space for 7 items, but in qgroup reservation, we need reserve space only for 3 items. So we implement new metadata reservation functions for the snapshot/subvolume creation. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-28 18:04:33 +08:00
u64 qgroup_reserved;
Btrfs: Integrate metadata reservation with start_transaction Besides simplify the code, this change makes sure all metadata reservation for normal metadata operations are released after committing transaction. Changes since V1: Add code that check if unlink and rmdir will free space. Add ENOSPC handling for clone ioctl. Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-05-16 22:48:46 +08:00
/* extra metadata reseration for relocation */
int error;
Btrfs: Add readonly snapshots support Usage: Set BTRFS_SUBVOL_RDONLY of btrfs_ioctl_vol_arg_v2->flags, and call ioctl(BTRFS_I0CTL_SNAP_CREATE_V2). Implementation: - Set readonly bit of btrfs_root_item->flags. - Add readonly checks in btrfs_permission (inode_permission), btrfs_setattr, btrfs_set/remove_xattr and some ioctls. Changelog for v3: - Eliminate btrfs_root->readonly, but check btrfs_root->root_item.flags. - Rename BTRFS_ROOT_SNAP_RDONLY to BTRFS_ROOT_SUBVOL_RDONLY. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
2010-12-20 16:04:08 +08:00
bool readonly;
Btrfs: Move snapshot creation to commit time It is very difficult to create a consistent snapshot of the btree when other writers may update the btree before the commit is done. This changes the snapshot creation to happen during the commit, while no other updates are possible. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-01-09 04:46:30 +08:00
struct list_head list;
};
Btrfs: delay commits during fsync to allow more writers Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-08-11 04:22:09 +08:00
static inline void btrfs_set_inode_last_trans(struct btrfs_trans_handle *trans,
struct inode *inode)
{
BTRFS_I(inode)->last_trans = trans->transaction->transid;
Btrfs: avoid tree log commit when there are no changes rpm has a habit of running fdatasync when the file hasn't changed. We already detect if a file hasn't been changed in the current transaction but it might have been sent to the tree-log in this transaction and not changed since the last call to fsync. In this case, we want to avoid a tree log sync, which includes a number of synchronous writes and barriers. This commit extends the existing tracking of the last transaction to change a file to also track the last sub-transaction. The end result is that rpm -ivh and -Uvh are roughly twice as fast, and on par with ext3. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-10-14 01:21:08 +08:00
BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
Btrfs: fix a bug in checking whether a inode is already in log This is based on Josef's "Btrfs: turbo charge fsync". The current btrfs checks if an inode is in log by comparing root's last_log_commit to inode's last_sub_trans[2]. But the problem is that this root->last_log_commit is shared among inodes. Say we have N inodes to be logged, after the first inode, root's last_log_commit is updated and the N-1 remained files will be skipped. This fixes the bug by keeping a local copy of root's last_log_commit inside each inode and this local copy will be maintained itself. [1]: we regard each log transaction as a subset of btrfs's transaction, i.e. sub_trans Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
2012-08-29 15:07:55 +08:00
BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
Btrfs: delay commits during fsync to allow more writers Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-08-11 04:22:09 +08:00
}
Btrfs: transaction rework Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-03-23 03:59:16 +08:00
int btrfs_end_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root);
struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
Btrfs: Integrate metadata reservation with start_transaction Besides simplify the code, this change makes sure all metadata reservation for normal metadata operations are released after committing transaction. Changes since V1: Add code that check if unlink and rmdir will free space. Add ENOSPC handling for clone ioctl. Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-05-16 22:48:46 +08:00
int num_items);
Btrfs: improve the noflush reservation In some places(such as: evicting inode), we just can not flush the reserved space of delalloc, flushing the delayed directory index and delayed inode is OK, but we don't try to flush those things and just go back when there is no enough space to be reserved. This patch fixes this problem. We defined 3 types of the flush operations: NO_FLUSH, FLUSH_LIMIT and FLUSH_ALL. If we can in the transaction, we should not flush anything, or the deadlock would happen, so use NO_FLUSH. If we flushing the reserved space of delalloc would cause deadlock, use FLUSH_LIMIT. In the other cases, FLUSH_ALL is used, and we will flush all things. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-10-16 19:33:38 +08:00
struct btrfs_trans_handle *btrfs_start_transaction_lflush(
Btrfs: fix corrupted metadata in the snapshot When we delete a inode, we will remove all the delayed items including delayed inode update, and then truncate all the relative metadata. If there is lots of metadata, we will end the current transaction, and start a new transaction to truncate the left metadata. In this way, we will leave a inode item that its link counter is > 0, and also may leave some directory index items in fs/file tree after the current transaction ends. In other words, the metadata in this fs/file tree is inconsistent. If we create a snapshot for this tree now, we will find a inode with corrupted metadata in the new snapshot, and we won't continue to drop the left metadata, because its link counter is not 0. We fix this problem by updating the inode item before the current transaction ends. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
2012-09-07 15:43:32 +08:00
struct btrfs_root *root, int num_items);
Btrfs: take away the num_items argument from btrfs_join_transaction I keep forgetting that btrfs_join_transaction() just ignores the num_items argument, which leads me to sending pointless patches and looking stupid :). So just kill the num_items argument from btrfs_join_transaction and btrfs_start_ioctl_transaction, since neither of them use it. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2011-04-14 00:54:33 +08:00
struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root);
struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root);
Btrfs: fix orphan transaction on the freezed filesystem With the following debug patch: static int btrfs_freeze(struct super_block *sb) { + struct btrfs_fs_info *fs_info = btrfs_sb(sb); + struct btrfs_transaction *trans; + + spin_lock(&fs_info->trans_lock); + trans = fs_info->running_transaction; + if (trans) { + printk("Transid %llu, use_count %d, num_writer %d\n", + trans->transid, atomic_read(&trans->use_count), + atomic_read(&trans->num_writers)); + } + spin_unlock(&fs_info->trans_lock); return 0; } I found there was a orphan transaction after the freeze operation was done. It is because the transaction may not be committed when the transaction handle end even though it is the last handle of the current transaction. This design avoid committing the transaction frequently, but also introduce the above problem. So I add btrfs_attach_transaction() which can catch the current transaction and commit it. If there is no transaction, it will return ENOENT, and do not anything. This function also can be used to instead of btrfs_join_transaction_freeze() because it don't increase the writer counter and don't start a new transaction, so it also can fix the deadlock between sync and freeze. Besides that, it is used to instead of btrfs_join_transaction() in transaction_kthread(), because if there is no transaction, the transaction kthread needn't anything. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
2012-09-20 15:54:00 +08:00
struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root);
Btrfs: fix uncompleted transaction In some cases, we need commit the current transaction, but don't want to start a new one if there is no running transaction, so we introduce the function - btrfs_attach_transaction(), which can catch the current transaction, and return -ENOENT if there is no running transaction. But no running transaction doesn't mean the current transction completely, because we removed the running transaction before it completes. In some cases, it doesn't matter. But in some special cases, such as freeze fs, we hope the transaction is fully on disk, it will introduce some bugs, for example, we may feeze the fs and dump the data in the disk, if the transction doesn't complete, we would dump inconsistent data. So we need fix the above problem for those cases. We fixes this problem by introducing a function: btrfs_attach_transaction_barrier() if we hope all the transaction is fully on the disk, even they are not running, we can use this function. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20 17:17:06 +08:00
struct btrfs_trans_handle *btrfs_attach_transaction_barrier(
struct btrfs_root *root);
Btrfs: take away the num_items argument from btrfs_join_transaction I keep forgetting that btrfs_join_transaction() just ignores the num_items argument, which leads me to sending pointless patches and looking stupid :). So just kill the num_items argument from btrfs_join_transaction and btrfs_start_ioctl_transaction, since neither of them use it. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2011-04-14 00:54:33 +08:00
struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root);
Btrfs: add START_SYNC, WAIT_SYNC ioctls START_SYNC will start a sync/commit, but not wait for it to complete. Any modification started after the ioctl returns is guaranteed not to be included in the commit. If a non-NULL pointer is passed, the transaction id will be returned to userspace. WAIT_SYNC will wait for any in-progress commit to complete. If a transaction id is specified, the ioctl will block and then return (success) when the specified transaction has committed. If it has already committed when we call the ioctl, it returns immediately. If the specified transaction doesn't exist, it returns EINVAL. If no transaction id is specified, WAIT_SYNC will wait for the currently committing transaction to finish it's commit to disk. If there is no currently committing transaction, it returns success. These ioctls are useful for applications which want to impose an ordering on when fs modifications reach disk, but do not want to wait for the full (slow) commit process to do so. Picky callers can take the transid returned by START_SYNC and feed it to WAIT_SYNC, and be certain to wait only as long as necessary for the transaction _they_ started to reach disk. Sloppy callers can START_SYNC and WAIT_SYNC without a transid, and provided they didn't wait too long between the calls, they will get the same result. However, if a second commit starts before they call WAIT_SYNC, they may end up waiting longer for it to commit as well. Even so, a START_SYNC+WAIT_SYNC still guarantees that any operation completed before the START_SYNC reaches disk. Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-10-30 03:41:32 +08:00
int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid);
Btrfs: transaction rework Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-03-23 03:59:16 +08:00
int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root);
Btrfs: add compat ioctl Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-06-09 03:33:54 +08:00
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE) This commit introduces a new kind of back reference for btrfs metadata. Once a filesystem has been mounted with this commit, IT WILL NO LONGER BE MOUNTABLE BY OLDER KERNELS. When a tree block in subvolume tree is cow'd, the reference counts of all extents it points to are increased by one. At transaction commit time, the old root of the subvolume is recorded in a "dead root" data structure, and the btree it points to is later walked, dropping reference counts and freeing any blocks where the reference count goes to 0. The increments done during cow and decrements done after commit cancel out, and the walk is a very expensive way to go about freeing the blocks that are no longer referenced by the new btree root. This commit reduces the transaction overhead by avoiding the need for dead root records. When a non-shared tree block is cow'd, we free the old block at once, and the new block inherits old block's references. When a tree block with reference count > 1 is cow'd, we increase the reference counts of all extents the new block points to by one, and decrease the old block's reference count by one. This dead tree avoidance code removes the need to modify the reference counts of lower level extents when a non-shared tree block is cow'd. But we still need to update back ref for all pointers in the block. This is because the location of the block is recorded in the back ref item. We can solve this by introducing a new type of back ref. The new back ref provides information about pointer's key, level and in which tree the pointer lives. This information allow us to find the pointer by searching the tree. The shortcoming of the new back ref is that it only works for pointers in tree blocks referenced by their owner trees. This is mostly a problem for snapshots, where resolving one of these fuzzy back references would be O(number_of_snapshots) and quite slow. The solution used here is to use the fuzzy back references in the common case where a given tree block is only referenced by one root, and use the full back references when multiple roots have a reference on a given block. This commit adds per subvolume red-black tree to keep trace of cached inodes. The red-black tree helps the balancing code to find cached inodes whose inode numbers within a given range. This commit improves the balancing code by introducing several data structures to keep the state of balancing. The most important one is the back ref cache. It caches how the upper level tree blocks are referenced. This greatly reduce the overhead of checking back ref. The improved balancing code scales significantly better with a large number of snapshots. This is a very large commit and was written in a number of pieces. But, they depend heavily on the disk format change and were squashed together to make sure git bisect didn't end up in a bad state wrt space balancing or the format change. Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 22:45:14 +08:00
int btrfs_add_dead_root(struct btrfs_root *root);
btrfs: remove cache only arguments from defrag path The entry point at the defrag ioctl always sets "cache only" to 0; the codepaths haven't run for a long time as far as I can tell. Chris says they're dead code, so remove them. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-01 02:21:12 +08:00
int btrfs_defrag_root(struct btrfs_root *root);
btrfs: clean snapshots one by one Each time pick one dead root from the list and let the caller know if it's needed to continue. This should improve responsiveness during umount and balance which at some point waits for cleaning all currently queued dead roots. A new dead root is added to the end of the list, so the snapshots disappear in the order of deletion. The snapshot cleaning work is now done only from the cleaner thread and the others wake it if needed. Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-03-12 23:13:28 +08:00
int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root);
Btrfs: Create extent_buffer interface for large blocksizes Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-10-16 04:14:19 +08:00
int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root);
Btrfs: async transaction commit Add support for an async transaction commit that is ordered such that any subsequent operations will join the following transaction, but does not wait until the current commit is fully on disk. This avoids much of the latency associated with the btrfs_commit_transaction for callers concerned with serialization and not safety. The wait_for_unblock flag controls whether we wait for the 'middle' portion of commit_transaction to complete, which is necessary if the caller expects some of the modifications contained in the commit to be available (this is the case for subvol/snapshot creation). Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-10-30 03:37:34 +08:00
int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
int wait_for_unblock);
Add btrfs_end_transaction_throttle to force writers to wait for pending commits The existing throttle mechanism was often not sufficient to prevent new writers from coming in and making a given transaction run forever. This adds an explicit wait at the end of most operations so they will allow the current transaction to close. There is no wait inside file_write, inode updates, or cow filling, all which have different deadlock possibilities. This is a temporary measure until better asynchronous commit support is added. This code leads to stalls as it waits for data=ordered writeback, and it really needs to be fixed. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-06-26 04:01:31 +08:00
int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
struct btrfs_root *root);
btrfs: implement delayed inode items operation Changelog V5 -> V6: - Fix oom when the memory load is high, by storing the delayed nodes into the root's radix tree, and letting btrfs inodes go. Changelog V4 -> V5: - Fix the race on adding the delayed node to the inode, which is spotted by Chris Mason. - Merge Chris Mason's incremental patch into this patch. - Fix deadlock between readdir() and memory fault, which is reported by Itaru Kitayama. Changelog V3 -> V4: - Fix nested lock, which is reported by Itaru Kitayama, by updating space cache inode in time. Changelog V2 -> V3: - Fix the race between the delayed worker and the task which does delayed items balance, which is reported by Tsutomu Itoh. - Modify the patch address David Sterba's comment. - Fix the bug of the cpu recursion spinlock, reported by Chris Mason Changelog V1 -> V2: - break up the global rb-tree, use a list to manage the delayed nodes, which is created for every directory and file, and used to manage the delayed directory name index items and the delayed inode item. - introduce a worker to deal with the delayed nodes. Compare with Ext3/4, the performance of file creation and deletion on btrfs is very poor. the reason is that btrfs must do a lot of b+ tree insertions, such as inode item, directory name item, directory name index and so on. If we can do some delayed b+ tree insertion or deletion, we can improve the performance, so we made this patch which implemented delayed directory name index insertion/deletion and delayed inode update. Implementation: - introduce a delayed root object into the filesystem, that use two lists to manage the delayed nodes which are created for every file/directory. One is used to manage all the delayed nodes that have delayed items. And the other is used to manage the delayed nodes which is waiting to be dealt with by the work thread. - Every delayed node has two rb-tree, one is used to manage the directory name index which is going to be inserted into b+ tree, and the other is used to manage the directory name index which is going to be deleted from b+ tree. - introduce a worker to deal with the delayed operation. This worker is used to deal with the works of the delayed directory name index items insertion and deletion and the delayed inode update. When the delayed items is beyond the lower limit, we create works for some delayed nodes and insert them into the work queue of the worker, and then go back. When the delayed items is beyond the upper bound, we create works for all the delayed nodes that haven't been dealt with, and insert them into the work queue of the worker, and then wait for that the untreated items is below some threshold value. - When we want to insert a directory name index into b+ tree, we just add the information into the delayed inserting rb-tree. And then we check the number of the delayed items and do delayed items balance. (The balance policy is above.) - When we want to delete a directory name index from the b+ tree, we search it in the inserting rb-tree at first. If we look it up, just drop it. If not, add the key of it into the delayed deleting rb-tree. Similar to the delayed inserting rb-tree, we also check the number of the delayed items and do delayed items balance. (The same to inserting manipulation) - When we want to update the metadata of some inode, we cached the data of the inode into the delayed node. the worker will flush it into the b+ tree after dealing with the delayed insertion and deletion. - We will move the delayed node to the tail of the list after we access the delayed node, By this way, we can cache more delayed items and merge more inode updates. - If we want to commit transaction, we will deal with all the delayed node. - the delayed node will be freed when we free the btrfs inode. - Before we log the inode items, we commit all the directory name index items and the delayed inode update. I did a quick test by the benchmark tool[1] and found we can improve the performance of file creation by ~15%, and file deletion by ~20%. Before applying this patch: Create files: Total files: 50000 Total time: 1.096108 Average time: 0.000022 Delete files: Total files: 50000 Total time: 1.510403 Average time: 0.000030 After applying this patch: Create files: Total files: 50000 Total time: 0.932899 Average time: 0.000019 Delete files: Total files: 50000 Total time: 1.215732 Average time: 0.000024 [1] http://marc.info/?l=linux-btrfs&m=128212635122920&q=p3 Many thanks for Kitayama-san's help! Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Reviewed-by: David Sterba <dave@jikos.cz> Tested-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com> Tested-by: Itaru Kitayama <kitayama@cl.bb4u.ne.jp> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-04-22 18:12:22 +08:00
int btrfs_end_transaction_dmeta(struct btrfs_trans_handle *trans,
struct btrfs_root *root);
Btrfs: Introduce global metadata reservation Reserve metadata space for extent tree, checksum tree and root tree Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-05-16 22:49:58 +08:00
int btrfs_should_end_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root);
Btrfs: Throttle operations if the reference cache gets too large A large reference cache is directly related to a lot of work pending for the cleaner thread. This throttles back new operations based on the size of the reference cache so the cleaner thread will be able to keep up. Overall, this actually makes the FS faster because the cleaner thread will be more likely to find things in cache. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-07-30 04:15:18 +08:00
void btrfs_throttle(struct btrfs_root *root);
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE) This commit introduces a new kind of back reference for btrfs metadata. Once a filesystem has been mounted with this commit, IT WILL NO LONGER BE MOUNTABLE BY OLDER KERNELS. When a tree block in subvolume tree is cow'd, the reference counts of all extents it points to are increased by one. At transaction commit time, the old root of the subvolume is recorded in a "dead root" data structure, and the btree it points to is later walked, dropping reference counts and freeing any blocks where the reference count goes to 0. The increments done during cow and decrements done after commit cancel out, and the walk is a very expensive way to go about freeing the blocks that are no longer referenced by the new btree root. This commit reduces the transaction overhead by avoiding the need for dead root records. When a non-shared tree block is cow'd, we free the old block at once, and the new block inherits old block's references. When a tree block with reference count > 1 is cow'd, we increase the reference counts of all extents the new block points to by one, and decrease the old block's reference count by one. This dead tree avoidance code removes the need to modify the reference counts of lower level extents when a non-shared tree block is cow'd. But we still need to update back ref for all pointers in the block. This is because the location of the block is recorded in the back ref item. We can solve this by introducing a new type of back ref. The new back ref provides information about pointer's key, level and in which tree the pointer lives. This information allow us to find the pointer by searching the tree. The shortcoming of the new back ref is that it only works for pointers in tree blocks referenced by their owner trees. This is mostly a problem for snapshots, where resolving one of these fuzzy back references would be O(number_of_snapshots) and quite slow. The solution used here is to use the fuzzy back references in the common case where a given tree block is only referenced by one root, and use the full back references when multiple roots have a reference on a given block. This commit adds per subvolume red-black tree to keep trace of cached inodes. The red-black tree helps the balancing code to find cached inodes whose inode numbers within a given range. This commit improves the balancing code by introducing several data structures to keep the state of balancing. The most important one is the back ref cache. It caches how the upper level tree blocks are referenced. This greatly reduce the overhead of checking back ref. The improved balancing code scales significantly better with a large number of snapshots. This is a very large commit and was written in a number of pieces. But, they depend heavily on the disk format change and were squashed together to make sure git bisect didn't end up in a bad state wrt space balancing or the format change. Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 22:45:14 +08:00
int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
struct btrfs_root *root);
Btrfs: Record dirty pages tree-log pages in an extent_io tree This is the same way the transaction code makes sure that all the other tree blocks are safely on disk. There's an extent_io tree for each root, and any blocks allocated to the tree logs are recorded in that tree. At tree-log sync, the extent_io tree is walked to flush down the dirty pages and wait for them. The main benefit is less time spent walking the tree log and skipping clean pages, and getting sequential IO down to the drive. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-12 04:17:57 +08:00
int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
Btrfs: Avoid superfluous tree-log writeout We allow two log transactions at a time, but use same flag to mark dirty tree-log btree blocks. So we may flush dirty blocks belonging to newer log transaction when committing a log transaction. This patch fixes the issue by using two flags to mark dirty tree-log btree blocks. Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-12 17:33:26 +08:00
struct extent_io_tree *dirty_pages, int mark);
Btrfs: streamline tree-log btree block writeout Syncing the tree log is a 3 phase operation. 1) write and wait for all the tree log blocks for a given root. 2) write and wait for all the tree log blocks for the tree of tree log roots. 3) write and wait for the super blocks (barriers here) This isn't as efficient as it could be because there is no requirement to wait for the blocks from step one to hit the disk before we start writing the blocks from step two. This commit changes the sequence so that we don't start waiting until all the tree blocks from both steps one and two have been sent to disk. We do this by breaking up btrfs_write_wait_marked_extents into two functions, which is trivial because it was already broken up into two parts. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-10-14 01:29:19 +08:00
int btrfs_write_marked_extents(struct btrfs_root *root,
Btrfs: Avoid superfluous tree-log writeout We allow two log transactions at a time, but use same flag to mark dirty tree-log btree blocks. So we may flush dirty blocks belonging to newer log transaction when committing a log transaction. This patch fixes the issue by using two flags to mark dirty tree-log btree blocks. Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-12 17:33:26 +08:00
struct extent_io_tree *dirty_pages, int mark);
Btrfs: streamline tree-log btree block writeout Syncing the tree log is a 3 phase operation. 1) write and wait for all the tree log blocks for a given root. 2) write and wait for all the tree log blocks for the tree of tree log roots. 3) write and wait for the super blocks (barriers here) This isn't as efficient as it could be because there is no requirement to wait for the blocks from step one to hit the disk before we start writing the blocks from step two. This commit changes the sequence so that we don't start waiting until all the tree blocks from both steps one and two have been sent to disk. We do this by breaking up btrfs_write_wait_marked_extents into two functions, which is trivial because it was already broken up into two parts. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-10-14 01:29:19 +08:00
int btrfs_wait_marked_extents(struct btrfs_root *root,
Btrfs: Avoid superfluous tree-log writeout We allow two log transactions at a time, but use same flag to mark dirty tree-log btree blocks. So we may flush dirty blocks belonging to newer log transaction when committing a log transaction. This patch fixes the issue by using two flags to mark dirty tree-log btree blocks. Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-11-12 17:33:26 +08:00
struct extent_io_tree *dirty_pages, int mark);
Btrfs: Introduce global metadata reservation Reserve metadata space for extent tree, checksum tree and root tree Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-05-16 22:49:58 +08:00
int btrfs_transaction_blocked(struct btrfs_fs_info *info);
Btrfs: be more polite in the async caching threads The semaphore used by the async caching threads can prevent a transaction commit, which can make the FS appear to stall. This releases the semaphore more often when a transaction commit is in progress. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-30 22:04:48 +08:00
int btrfs_transaction_in_commit(struct btrfs_fs_info *info);
Btrfs: transaction handles everywhere Signed-off-by: Chris Mason <chris.mason@oracle.com>
2007-03-17 04:20:31 +08:00
#endif