[RFC,v2,2/5] btrfs: Add btrfs_start_transaction_freeze() to start transaction in btrfs_freeze()

Commit Message

Qu Wenruo Jan. 20, 2015, 9:05 a.m. UTC

Add btrfs_start_transaction_freeze() function.

This is needed for btrfs_freeze() to handle the pending changes.
If there is no running transaction when btrfs_freeze() is called,
btrfs_freeze() needs to start a transaction to handle the pending
changes, and it can't initial a sb_start_intwrite() call.

Signed-off-by: Qu Wenruo <[e-mail]>
---
 fs/btrfs/transaction.c | 8 ++++++++
 fs/btrfs/transaction.h | 2 ++
 2 files changed, 10 insertions(+)

Patch

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index e88b59d..13a2b67 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -570,6 +570,14 @@  struct btrfs_trans_handle *btrfs_start_transaction_lflush(
 				 BTRFS_RESERVE_FLUSH_LIMIT);
 }
 
+/* Only used in btrfs_freeze() */
+struct btrfs_trans_handle *btrfs_start_transaction_freeze(
+					struct btrfs_root *root, int num_items)
+{
+	return start_transaction(root, num_items, __TRANS_START,
+				 BTRFS_RESERVE_FLUSH_ALL);
+}
+
 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
 {
 	return start_transaction(root, 0, TRANS_JOIN, 0);
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index 00ed29c..49bd7eb 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -140,6 +140,8 @@  struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
 						   int num_items);
 struct btrfs_trans_handle *btrfs_start_transaction_lflush(
 					struct btrfs_root *root, int num_items);
+struct btrfs_trans_handle *btrfs_start_transaction_freeze(
+					struct btrfs_root *root, int num_items);
 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root);
 struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root);
 struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root);