Btrfs: implement online profile changing
Profile changing is done by launching a balance with
BTRFS_BALANCE_CONVERT bits set and target fields of respective
btrfs_balance_args structs initialized. Profile reducing code in this
case will pick restriper's target profile if it's available instead of
doing a blind reduce. If target profile is not yet available it goes
back to a plain reduce.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index a1a18ea..e6a832e 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3030,7 +3030,9 @@
/*
* @flags: available profiles in extended format (see ctree.h)
*
- * Returns reduced profile in chunk format.
+ * Returns reduced profile in chunk format. If profile changing is in
+ * progress (either running or paused) picks the target profile (if it's
+ * already available), otherwise falls back to plain reducing.
*/
u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
{
@@ -3042,6 +3044,34 @@
u64 num_devices = root->fs_info->fs_devices->rw_devices +
root->fs_info->fs_devices->missing_devices;
+ /* pick restriper's target profile if it's available */
+ spin_lock(&root->fs_info->balance_lock);
+ if (root->fs_info->balance_ctl) {
+ struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
+ u64 tgt = 0;
+
+ if ((flags & BTRFS_BLOCK_GROUP_DATA) &&
+ (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
+ (flags & bctl->data.target)) {
+ tgt = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
+ } else if ((flags & BTRFS_BLOCK_GROUP_SYSTEM) &&
+ (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
+ (flags & bctl->sys.target)) {
+ tgt = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
+ } else if ((flags & BTRFS_BLOCK_GROUP_METADATA) &&
+ (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
+ (flags & bctl->meta.target)) {
+ tgt = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
+ }
+
+ if (tgt) {
+ spin_unlock(&root->fs_info->balance_lock);
+ flags = tgt;
+ goto out;
+ }
+ }
+ spin_unlock(&root->fs_info->balance_lock);
+
if (num_devices == 1)
flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
if (num_devices < 4)
@@ -3065,6 +3095,7 @@
flags &= ~BTRFS_BLOCK_GROUP_RAID0;
}
+out:
/* extended -> chunk profile */
flags &= ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
return flags;
@@ -6795,6 +6826,29 @@
u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
+ if (root->fs_info->balance_ctl) {
+ struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
+ u64 tgt = 0;
+
+ /* pick restriper's target profile and return */
+ if (flags & BTRFS_BLOCK_GROUP_DATA &&
+ bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
+ tgt = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
+ } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
+ bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
+ tgt = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
+ } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
+ bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
+ tgt = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
+ }
+
+ if (tgt) {
+ /* extended -> chunk profile */
+ tgt &= ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
+ return tgt;
+ }
+ }
+
/*
* we add in the count of missing devices because we want
* to make sure that any RAID levels on a degraded FS
