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-rw-r--r--fs/btrfs/transaction.c37
1 files changed, 34 insertions, 3 deletions
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 67e84939b758..e18eb75e6fa3 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -454,7 +454,7 @@ start_transaction(struct btrfs_root *root, unsigned int num_items,
bool enforce_qgroups)
{
struct btrfs_fs_info *fs_info = root->fs_info;
-
+ struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
struct btrfs_trans_handle *h;
struct btrfs_transaction *cur_trans;
u64 num_bytes = 0;
@@ -483,13 +483,28 @@ start_transaction(struct btrfs_root *root, unsigned int num_items,
* the appropriate flushing if need be.
*/
if (num_items && root != fs_info->chunk_root) {
+ struct btrfs_block_rsv *rsv = &fs_info->trans_block_rsv;
+ u64 delayed_refs_bytes = 0;
+
qgroup_reserved = num_items * fs_info->nodesize;
ret = btrfs_qgroup_reserve_meta_pertrans(root, qgroup_reserved,
enforce_qgroups);
if (ret)
return ERR_PTR(ret);
+ /*
+ * We want to reserve all the bytes we may need all at once, so
+ * we only do 1 enospc flushing cycle per transaction start. We
+ * accomplish this by simply assuming we'll do 2 x num_items
+ * worth of delayed refs updates in this trans handle, and
+ * refill that amount for whatever is missing in the reserve.
+ */
num_bytes = btrfs_calc_trans_metadata_size(fs_info, num_items);
+ if (delayed_refs_rsv->full == 0) {
+ delayed_refs_bytes = num_bytes;
+ num_bytes <<= 1;
+ }
+
/*
* Do the reservation for the relocation root creation
*/
@@ -498,8 +513,24 @@ start_transaction(struct btrfs_root *root, unsigned int num_items,
reloc_reserved = true;
}
- ret = btrfs_block_rsv_add(root, &fs_info->trans_block_rsv,
- num_bytes, flush);
+ ret = btrfs_block_rsv_add(root, rsv, num_bytes, flush);
+ if (ret)
+ goto reserve_fail;
+ if (delayed_refs_bytes) {
+ btrfs_migrate_to_delayed_refs_rsv(fs_info, rsv,
+ delayed_refs_bytes);
+ num_bytes -= delayed_refs_bytes;
+ }
+ } else if (num_items == 0 && flush == BTRFS_RESERVE_FLUSH_ALL &&
+ !delayed_refs_rsv->full) {
+ /*
+ * Some people call with btrfs_start_transaction(root, 0)
+ * because they can be throttled, but have some other mechanism
+ * for reserving space. We still want these guys to refill the
+ * delayed block_rsv so just add 1 items worth of reservation
+ * here.
+ */
+ ret = btrfs_delayed_refs_rsv_refill(fs_info, flush);
if (ret)
goto reserve_fail;
}
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