Btrfs: allow for canceling restriper
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>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 1afda75..dfc136c 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1216,6 +1216,7 @@
struct mutex balance_mutex;
atomic_t balance_running;
atomic_t balance_pause_req;
+ atomic_t balance_cancel_req;
struct btrfs_balance_control *balance_ctl;
wait_queue_head_t balance_wait_q;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 8ce8374..c23b82d 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2006,6 +2006,7 @@
mutex_init(&fs_info->balance_mutex);
atomic_set(&fs_info->balance_running, 0);
atomic_set(&fs_info->balance_pause_req, 0);
+ atomic_set(&fs_info->balance_cancel_req, 0);
fs_info->balance_ctl = NULL;
init_waitqueue_head(&fs_info->balance_wait_q);
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index f572c53..6085221 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3076,6 +3076,8 @@
bargs->state |= BTRFS_BALANCE_STATE_RUNNING;
if (atomic_read(&fs_info->balance_pause_req))
bargs->state |= BTRFS_BALANCE_STATE_PAUSE_REQ;
+ if (atomic_read(&fs_info->balance_cancel_req))
+ bargs->state |= BTRFS_BALANCE_STATE_CANCEL_REQ;
memcpy(&bargs->data, &bctl->data, sizeof(bargs->data));
memcpy(&bargs->meta, &bctl->meta, sizeof(bargs->meta));
@@ -3157,6 +3159,8 @@
switch (cmd) {
case BTRFS_BALANCE_CTL_PAUSE:
return btrfs_pause_balance(root->fs_info);
+ case BTRFS_BALANCE_CTL_CANCEL:
+ return btrfs_cancel_balance(root->fs_info);
}
return -EINVAL;
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index e972e11..cd19d10 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -111,6 +111,7 @@
/* balance control ioctl modes */
#define BTRFS_BALANCE_CTL_PAUSE 1
+#define BTRFS_BALANCE_CTL_CANCEL 2
/*
* this is packed, because it should be exactly the same as its disk
@@ -142,6 +143,7 @@
#define BTRFS_BALANCE_STATE_RUNNING (1ULL << 0)
#define BTRFS_BALANCE_STATE_PAUSE_REQ (1ULL << 1)
+#define BTRFS_BALANCE_STATE_CANCEL_REQ (1ULL << 2)
struct btrfs_ioctl_balance_args {
__u64 flags; /* in/out */
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index d32660c..c326673 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2492,7 +2492,8 @@
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 @@
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 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 @@
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.
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 80953af..caa9abd 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -274,6 +274,7 @@
struct btrfs_ioctl_balance_args *bargs);
int btrfs_recover_balance(struct btrfs_root *tree_root);
int btrfs_pause_balance(struct btrfs_fs_info *fs_info);
+int btrfs_cancel_balance(struct btrfs_fs_info *fs_info);
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,