On 07/16/2011 02:29 AM, Josef Bacik wrote:
> Currently we reserve enough space to COW an entirely full btree for every
> extent
> we have reserved for an inode. This _sucks_, because you only need to COW
> once,
> and then everybody else is ok. Unfortunately we don't know we'll all be able
> to
> get into the same transaction so that's what we have had to do. But the
> global
> reserve holds a reservation large enough to cover a large percentage of all
> the
> metadata currently in the fs. So all we really need to account for is any new
> blocks that we may allocate. So fix this by
>
> 1) Passing to btrfs_alloc_free_block() wether this is a new block or a COW
> block. If it is a COW block we use the global reserve, if not we use the
> trans->block_rsv.
> 2) Reduce the amount of space we reserve. Since we don't need to account for
> cow'ing the tree we can just keep track of new blocks to reserve, which
> greatly
> reduces the reservation amount.
>
> This makes my basic random write test go from 3 mb/s to 75 mb/s. I've tested
> this with my horrible ENOSPC test and it seems to work out fine. Thanks,
>
Hi, Josef,
After I patched this and did a "tar xf source.tar", I got lots of warnings,
Would you like to look into this?
------------[ cut here ]------------
WARNING: at fs/btrfs/extent-tree.c:5695 btrfs_alloc_free_block+0x178/0x340
[btrfs]()
Hardware name: QiTianM7150
Modules linked in: btrfs iptable_nat nf_nat zlib_deflate libcrc32c ebtable_nat
ebtables bridge stp llc cpufreq_ondemand acpi_cpufreq freq_table mperf be2iscsi
iscsi_boot_sysfs bnx2i cnic uio cxgb3i libcxgbi cxgb3 mdio iscsi_tcp
libiscsi_tcp libiscsi scsi_transport_iscsi ext3 jbd dm_mirror dm_region_hash
dm_log dm_mod sg ppdev serio_raw pcspkr i2c_i801 iTCO_wdt iTCO_vendor_support
sky2 parport_pc parport ext4 mbcache jbd2 sd_mod crc_t10dif pata_acpi
ata_generic ata_piix i915 drm_kms_helper drm i2c_algo_bit i2c_core video [last
unloaded: btrfs]
Pid: 16008, comm: umount Tainted: G W 2.6.39+ #9
Call Trace:
[<ffffffff81053baf>] warn_slowpath_common+0x7f/0xc0
[<ffffffff81053c0a>] warn_slowpath_null+0x1a/0x20
[<ffffffffa04d37d8>] btrfs_alloc_free_block+0x178/0x340 [btrfs]
[<ffffffffa0501768>] ? read_extent_buffer+0xd8/0x1d0 [btrfs]
[<ffffffffa04be625>] __btrfs_cow_block+0x155/0x5f0 [btrfs]
[<ffffffffa04bebcb>] btrfs_cow_block+0x10b/0x240 [btrfs]
[<ffffffffa04c4c8e>] btrfs_search_slot+0x49e/0x7a0 [btrfs]
[<ffffffffa04d2399>] btrfs_write_dirty_block_groups+0x1a9/0x4d0 [btrfs]
[<ffffffffa0512e20>] ? btrfs_tree_unlock+0x50/0x50 [btrfs]
[<ffffffffa04df845>] commit_cowonly_roots+0x105/0x1e0 [btrfs]
[<ffffffffa04e0708>] btrfs_commit_transaction+0x428/0x850 [btrfs]
[<ffffffffa04df9b8>] ? wait_current_trans+0x28/0x100 [btrfs]
[<ffffffffa04e0c25>] ? join_transaction+0x25/0x250 [btrfs]
[<ffffffff81075590>] ? wake_up_bit+0x40/0x40
[<ffffffffa04bb187>] btrfs_sync_fs+0x67/0xd0 [btrfs]
[<ffffffff8116c27e>] __sync_filesystem+0x5e/0x90
[<ffffffff8116c38b>] sync_filesystem+0x4b/0x70
[<ffffffff811441c4>] generic_shutdown_super+0x34/0xf0
[<ffffffff81144316>] kill_anon_super+0x16/0x60
[<ffffffff81144a25>] deactivate_locked_super+0x45/0x70
[<ffffffff8114568a>] deactivate_super+0x4a/0x70
[<ffffffff8115efdc>] mntput_no_expire+0x13c/0x1c0
[<ffffffff8115f7bb>] sys_umount+0x7b/0x3a0
[<ffffffff81466b2b>] system_call_fastpath+0x16/0x1b
---[ end trace 9a65800674b03b84 ]---
thanks,
liubo
> Signed-off-by: Josef Bacik <jo...@redhat.com>
> ---
> fs/btrfs/ctree.c | 10 +++++-----
> fs/btrfs/ctree.h | 5 ++---
> fs/btrfs/disk-io.c | 3 ++-
> fs/btrfs/extent-tree.c | 20 +++++++++++++++-----
> fs/btrfs/ioctl.c | 2 +-
> 5 files changed, 25 insertions(+), 15 deletions(-)
>
> diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
> index 2e66786..fbd48e9 100644
> --- a/fs/btrfs/ctree.c
> +++ b/fs/btrfs/ctree.c
> @@ -206,7 +206,7 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
>
> cow = btrfs_alloc_free_block(trans, root, buf->len, 0,
> new_root_objectid, &disk_key, level,
> - buf->start, 0);
> + buf->start, 0, 1);
> if (IS_ERR(cow))
> return PTR_ERR(cow);
>
> @@ -412,7 +412,7 @@ static noinline int __btrfs_cow_block(struct
> btrfs_trans_handle *trans,
>
> cow = btrfs_alloc_free_block(trans, root, buf->len, parent_start,
> root->root_key.objectid, &disk_key,
> - level, search_start, empty_size);
> + level, search_start, empty_size, 0);
> if (IS_ERR(cow))
> return PTR_ERR(cow);
>
> @@ -1985,7 +1985,7 @@ static noinline int insert_new_root(struct
> btrfs_trans_handle *trans,
>
> c = btrfs_alloc_free_block(trans, root, root->nodesize, 0,
> root->root_key.objectid, &lower_key,
> - level, root->node->start, 0);
> + level, root->node->start, 0, 1);
> if (IS_ERR(c))
> return PTR_ERR(c);
>
> @@ -2112,7 +2112,7 @@ static noinline int split_node(struct
> btrfs_trans_handle *trans,
>
> split = btrfs_alloc_free_block(trans, root, root->nodesize, 0,
> root->root_key.objectid,
> - &disk_key, level, c->start, 0);
> + &disk_key, level, c->start, 0, 1);
> if (IS_ERR(split))
> return PTR_ERR(split);
>
> @@ -2937,7 +2937,7 @@ again:
>
> right = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
> root->root_key.objectid,
> - &disk_key, 0, l->start, 0);
> + &disk_key, 0, l->start, 0, 1);
> if (IS_ERR(right))
> return PTR_ERR(right);
>
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index 3ba4d5f..1accb56 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -2135,8 +2135,7 @@ static inline bool btrfs_mixed_space_info(struct
> btrfs_space_info *space_info)
> static inline u64 btrfs_calc_trans_metadata_size(struct btrfs_root *root,
> unsigned num_items)
> {
> - return (root->leafsize + root->nodesize * (BTRFS_MAX_LEVEL - 1)) *
> - 3 * num_items;
> + return root->leafsize * 3 * num_items;
> }
>
> void btrfs_put_block_group(struct btrfs_block_group_cache *cache);
> @@ -2161,7 +2160,7 @@ struct extent_buffer *btrfs_alloc_free_block(struct
> btrfs_trans_handle *trans,
> struct btrfs_root *root, u32 blocksize,
> u64 parent, u64 root_objectid,
> struct btrfs_disk_key *key, int level,
> - u64 hint, u64 empty_size);
> + u64 hint, u64 empty_size, int
> new_block);
> void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
> struct btrfs_root *root,
> struct extent_buffer *buf,
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 234a084..0245cad 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -1143,7 +1143,8 @@ static struct btrfs_root *alloc_log_tree(struct
> btrfs_trans_handle *trans,
> root->ref_cows = 0;
>
> leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
> - BTRFS_TREE_LOG_OBJECTID, NULL, 0, 0, 0);
> + BTRFS_TREE_LOG_OBJECTID, NULL, 0, 0, 0,
> + 1);
> if (IS_ERR(leaf)) {
> kfree(root);
> return ERR_CAST(leaf);
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 2e0f87b..e2dd833 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -5661,13 +5661,23 @@ struct extent_buffer *btrfs_init_new_buffer(struct
> btrfs_trans_handle *trans,
>
> static struct btrfs_block_rsv *
> use_block_rsv(struct btrfs_trans_handle *trans,
> - struct btrfs_root *root, u32 blocksize)
> + struct btrfs_root *root, u32 blocksize, int new_block)
> {
> - struct btrfs_block_rsv *block_rsv;
> + struct btrfs_block_rsv *block_rsv = NULL;
> struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
> int ret;
>
> - block_rsv = get_block_rsv(trans, root);
> + if (root->ref_cows) {
> + if (new_block)
> + block_rsv = trans->block_rsv;
> + else
> + block_rsv = global_rsv;
> + } else {
> + block_rsv = root->block_rsv;
> + }
> +
> + if (!block_rsv)
> + block_rsv = &root->fs_info->empty_block_rsv;
>
> if (block_rsv->size == 0) {
> ret = reserve_metadata_bytes(trans, root, block_rsv,
> @@ -5726,7 +5736,7 @@ struct extent_buffer *btrfs_alloc_free_block(struct
> btrfs_trans_handle *trans,
> struct btrfs_root *root, u32 blocksize,
> u64 parent, u64 root_objectid,
> struct btrfs_disk_key *key, int level,
> - u64 hint, u64 empty_size)
> + u64 hint, u64 empty_size, int new_block)
> {
> struct btrfs_key ins;
> struct btrfs_block_rsv *block_rsv;
> @@ -5735,7 +5745,7 @@ struct extent_buffer *btrfs_alloc_free_block(struct
> btrfs_trans_handle *trans,
> int ret;
>
>
> - block_rsv = use_block_rsv(trans, root, blocksize);
> + block_rsv = use_block_rsv(trans, root, blocksize, new_block);
> if (IS_ERR(block_rsv))
> return ERR_CAST(block_rsv);
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index fd252ff..39fb634 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -352,7 +352,7 @@ static noinline int create_subvol(struct btrfs_root *root,
> }
>
> leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
> - 0, objectid, NULL, 0, 0, 0);
> + 0, objectid, NULL, 0, 0, 0, 1);
> if (IS_ERR(leaf)) {
> ret = PTR_ERR(leaf);
> goto fail;
--
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