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Btrfs: allow for canceling restriper

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Implement an ioctl for canceling restriper.  Currently we wait until
relocation of the current block group is finished, in future this can be
done by triggering a commit.  Balance item is deleted and no memory
about the interrupted balance is kept.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This commit is contained in:
Ilya Dryomov
2012-01-16 22:04:49 +02:00
parent 837d5b6e46
commit a7e99c691a
6 changed files with 53 additions and 3 deletions
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47
fs/btrfs/volumes.c
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@@ -2492,7 +2492,8 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
key.type = BTRFS_CHUNK_ITEM_KEY;
while (1) {
if (atomic_read(&fs_info->balance_pause_req)) {
if (atomic_read(&fs_info->balance_pause_req) ||
atomic_read(&fs_info->balance_cancel_req)) {
ret = -ECANCELED;
goto error;
}
@@ -2560,7 +2561,10 @@ error:
static inline int balance_need_close(struct btrfs_fs_info *fs_info)
{
return atomic_read(&fs_info->balance_pause_req) == 0;
/* cancel requested || normal exit path */
return atomic_read(&fs_info->balance_cancel_req) ||
(atomic_read(&fs_info->balance_pause_req) == 0 &&
atomic_read(&fs_info->balance_cancel_req) == 0);
}
static void __cancel_balance(struct btrfs_fs_info *fs_info)
@@ -2586,7 +2590,8 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
int ret;
if (btrfs_fs_closing(fs_info) ||
atomic_read(&fs_info->balance_pause_req)) {
atomic_read(&fs_info->balance_pause_req) ||
atomic_read(&fs_info->balance_cancel_req)) {
ret = -EINVAL;
goto out;
}
@@ -2832,6 +2837,42 @@ int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
return ret;
}
int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
{
mutex_lock(&fs_info->balance_mutex);
if (!fs_info->balance_ctl) {
mutex_unlock(&fs_info->balance_mutex);
return -ENOTCONN;
}
atomic_inc(&fs_info->balance_cancel_req);
/*
* if we are running just wait and return, balance item is
* deleted in btrfs_balance in this case
*/
if (atomic_read(&fs_info->balance_running)) {
mutex_unlock(&fs_info->balance_mutex);
wait_event(fs_info->balance_wait_q,
atomic_read(&fs_info->balance_running) == 0);
mutex_lock(&fs_info->balance_mutex);
} else {
/* __cancel_balance needs volume_mutex */
mutex_unlock(&fs_info->balance_mutex);
mutex_lock(&fs_info->volume_mutex);
mutex_lock(&fs_info->balance_mutex);
if (fs_info->balance_ctl)
__cancel_balance(fs_info);
mutex_unlock(&fs_info->volume_mutex);
}
BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
atomic_dec(&fs_info->balance_cancel_req);
mutex_unlock(&fs_info->balance_mutex);
return 0;
}
/*
* shrinking a device means finding all of the device extents past
* the new size, and then following the back refs to the chunks.