Hi,
you are adding a new smp_mb, can you please explain why it's needed and
document it?
thanks,
dave
On Fri, Mar 18, 2011 at 04:55:07PM +0100, Arne Jansen wrote:
> This adds several synchronizations:
> - for a transaction commit, the scrub gets paused before the
> tree roots are committed until the super are safely on disk
> - during a log commit, scrubbing of supers is disabled
> - on unmount, the scrub gets cancelled
> - on device removal, the scrub for the particular device gets cancelled
>
> Signed-off-by: Arne Jansen <sensille@xxxxxxx>
> ---
> fs/btrfs/disk-io.c | 1 +
> fs/btrfs/transaction.c | 3 +++
> fs/btrfs/tree-log.c | 2 ++
> fs/btrfs/volumes.c | 2 ++
> 4 files changed, 8 insertions(+), 0 deletions(-)
>
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 3e1ea3e..924a366 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -2493,6 +2493,7 @@ int close_ctree(struct btrfs_root *root)
> fs_info->closing = 1;
> smp_mb();
>
> + btrfs_scrub_cancel(root);
> btrfs_put_block_group_cache(fs_info);
>
> /*
> diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
> index 3d73c8d..5a43b20 100644
> --- a/fs/btrfs/transaction.c
> +++ b/fs/btrfs/transaction.c
> @@ -1310,6 +1310,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
>
> WARN_ON(cur_trans != trans->transaction);
>
> + btrfs_scrub_pause(root);
> /* 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
> @@ -1391,6 +1392,8 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
>
> mutex_unlock(&root->fs_info->trans_mutex);
>
> + btrfs_scrub_continue(root);
> +
> if (current->journal_info == trans)
> current->journal_info = NULL;
>
> diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
> index 1f6788f..2be84fa 100644
> --- a/fs/btrfs/tree-log.c
> +++ b/fs/btrfs/tree-log.c
> @@ -2098,7 +2098,9 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
> * the running transaction open, so a full commit can't hop
> * in and cause problems either.
> */
> + btrfs_scrub_pause_super(root);
> write_ctree_super(trans, root->fs_info->tree_root, 1);
> + btrfs_scrub_continue_super(root);
> ret = 0;
>
> mutex_lock(&root->log_mutex);
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 7dc9fa5..ad3ea88 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -1330,6 +1330,8 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
> goto error_undo;
>
> device->in_fs_metadata = 0;
> + smp_mb();
^^^^^^^^
> + btrfs_scrub_cancel_dev(root, device);
>
> /*
> * the device list mutex makes sure that we don't change
> --
> 1.7.3.4
>
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