On 23.08.2011 22:01, Ilya Dryomov wrote:
> Implement an ioctl for pausing restriper. This pauses the relocation,
> but restripe is still considered to be "in progress": restriper item is
> not deleted, other volume operations cannot be started, etc. If paused
> in the middle of profile changing operation we will continue making
> allocations with the target profile.
>
> Add a hook to close_ctree() to be able to pause restriper and free it's
> data structures on unmount. (It's safe to unmount when restriper is in
> 'paused' state, we will resume with the same parameters on the next
> mount)
>
> Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
> ---
> fs/btrfs/disk-io.c | 3 +++
> fs/btrfs/ioctl.c | 2 ++
> fs/btrfs/ioctl.h | 1 +
> fs/btrfs/volumes.c | 44 ++++++++++++++++++++++++++++++++++++++++++--
> fs/btrfs/volumes.h | 2 ++
> 5 files changed, 50 insertions(+), 2 deletions(-)
>
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 662a6e6..7db5c50 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -2542,6 +2542,9 @@ int close_ctree(struct btrfs_root *root)
> fs_info->closing = 1;
> smp_mb();
>
> + /* pause restriper and free restripe_ctl */
> + btrfs_pause_restripe(root->fs_info, 1);
> +
> btrfs_scrub_cancel(root);
>
> /* wait for any defraggers to finish */
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index d8bdb67..61978ac 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -2921,6 +2921,8 @@ static long btrfs_ioctl_restripe_ctl(struct btrfs_root *root,
> switch (cmd) {
> case BTRFS_RESTRIPE_CTL_CANCEL:
> return btrfs_cancel_restripe(root->fs_info);
> + case BTRFS_RESTRIPE_CTL_PAUSE:
> + return btrfs_pause_restripe(root->fs_info, 0);
> }
>
> return -EINVAL;
> diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
> index 4f6ead5..e468d5b 100644
> --- a/fs/btrfs/ioctl.h
> +++ b/fs/btrfs/ioctl.h
> @@ -110,6 +110,7 @@ struct btrfs_ioctl_fs_info_args {
> };
>
> #define BTRFS_RESTRIPE_CTL_CANCEL 1
> +#define BTRFS_RESTRIPE_CTL_PAUSE 2
>
> struct btrfs_restripe_args {
> __u64 profiles;
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index cd43368..65deaa7 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -2555,7 +2555,8 @@ static int __btrfs_restripe(struct btrfs_root *dev_root)
> while (1) {
> struct btrfs_fs_info *fs_info = dev_root->fs_info;
>
> - if (test_bit(RESTRIPE_CANCEL_REQ, &fs_info->restripe_state)) {
> + if (test_bit(RESTRIPE_CANCEL_REQ, &fs_info->restripe_state) ||
> + test_bit(RESTRIPE_PAUSE_REQ, &fs_info->restripe_state)) {
> ret = -ECANCELED;
> goto error;
> }
> @@ -2730,7 +2731,9 @@ do_restripe:
> mutex_lock(&fs_info->restripe_mutex);
> clear_bit(RESTRIPE_RUNNING, &fs_info->restripe_state);
>
> - if (test_bit(RESTRIPE_CANCEL_REQ, &fs_info->restripe_state)) {
> + if (test_bit(RESTRIPE_CANCEL_REQ, &fs_info->restripe_state) ||
> + (!test_bit(RESTRIPE_PAUSE_REQ, &fs_info->restripe_state) &&
> + !test_bit(RESTRIPE_CANCEL_REQ, &fs_info->restripe_state))) {
> mutex_lock(&fs_info->volume_mutex);
>
> unset_restripe_control(fs_info);
> @@ -2858,6 +2861,43 @@ out:
> return ret;
> }
I don't see a difference in what CANCEL_REQ and PAUSE_REQ do, so it seems
one of them would be enough.
>
> +int btrfs_pause_restripe(struct btrfs_fs_info *fs_info, int unset)
> +{
> + int ret = 0;
> +
> + mutex_lock(&fs_info->restripe_mutex);
> + if (!fs_info->restripe_ctl) {
> + ret = -ENOTCONN;
> + goto out;
> + }
> +
> + /* only running restripe can be paused */
> + if (!test_bit(RESTRIPE_RUNNING, &fs_info->restripe_state)) {
> + ret = -ENOTCONN;
> + goto out_unset;
> + }
> +
> + set_bit(RESTRIPE_PAUSE_REQ, &fs_info->restripe_state);
> + while (test_bit(RESTRIPE_RUNNING, &fs_info->restripe_state)) {
> + mutex_unlock(&fs_info->restripe_mutex);
> + wait_event(fs_info->restripe_wait,
> + !test_bit(RESTRIPE_RUNNING,
> + &fs_info->restripe_state));
> + mutex_lock(&fs_info->restripe_mutex);
> + }
> + clear_bit(RESTRIPE_PAUSE_REQ, &fs_info->restripe_state);
> +
> +out_unset:
> + if (unset) {
> + mutex_lock(&fs_info->volume_mutex);
> + unset_restripe_control(fs_info);
> + mutex_unlock(&fs_info->volume_mutex);
> + }
> +out:
> + mutex_unlock(&fs_info->restripe_mutex);
> + return ret;
> +}
> +
This looks very similar to cancel_restripe. It should be easy to
merge them to one function without making a mess out of it.
> /*
> * shrinking a device means finding all of the device extents past
> * the new size, and then following the back refs to the chunks.
> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
> index dd1fa7f..b8c234a 100644
> --- a/fs/btrfs/volumes.h
> +++ b/fs/btrfs/volumes.h
> @@ -204,6 +204,7 @@ struct map_lookup {
> */
> #define RESTRIPE_RUNNING 0
> #define RESTRIPE_CANCEL_REQ 1
> +#define RESTRIPE_PAUSE_REQ 2
>
> struct btrfs_restripe_args;
> struct restripe_control {
> @@ -261,6 +262,7 @@ int btrfs_balance(struct btrfs_root *dev_root);
> int btrfs_restripe(struct restripe_control *rctl, int resume);
> int btrfs_recover_restripe(struct btrfs_root *tree_root);
> int btrfs_cancel_restripe(struct btrfs_fs_info *fs_info);
> +int btrfs_pause_restripe(struct btrfs_fs_info *fs_info, int unset);
> int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset);
> int find_free_dev_extent(struct btrfs_trans_handle *trans,
> struct btrfs_device *device, u64 num_bytes,
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