diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index 89116afda7a2..e5d85311d5d5 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -1483,7 +1483,7 @@ int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr, ulist_init(roots); ulist_init(tmp); - trans = btrfs_attach_transaction(root); + trans = btrfs_join_transaction_nostart(root); if (IS_ERR(trans)) { if (PTR_ERR(trans) != -ENOENT && PTR_ERR(trans) != -EROFS) { ret = PTR_ERR(trans); diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index 39b7bcde3c6f..e3adb714c04b 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -28,15 +28,18 @@ static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = { [TRANS_STATE_COMMIT_START] = (__TRANS_START | __TRANS_ATTACH), [TRANS_STATE_COMMIT_DOING] = (__TRANS_START | __TRANS_ATTACH | - __TRANS_JOIN), + __TRANS_JOIN | + __TRANS_JOIN_NOSTART), [TRANS_STATE_UNBLOCKED] = (__TRANS_START | __TRANS_ATTACH | __TRANS_JOIN | - __TRANS_JOIN_NOLOCK), + __TRANS_JOIN_NOLOCK | + __TRANS_JOIN_NOSTART), [TRANS_STATE_COMPLETED] = (__TRANS_START | __TRANS_ATTACH | __TRANS_JOIN | - __TRANS_JOIN_NOLOCK), + __TRANS_JOIN_NOLOCK | + __TRANS_JOIN_NOSTART), }; void btrfs_put_transaction(struct btrfs_transaction *transaction) @@ -543,7 +546,8 @@ start_transaction(struct btrfs_root *root, unsigned int num_items, ret = join_transaction(fs_info, type); if (ret == -EBUSY) { wait_current_trans(fs_info); - if (unlikely(type == TRANS_ATTACH)) + if (unlikely(type == TRANS_ATTACH || + type == TRANS_JOIN_NOSTART)) ret = -ENOENT; } } while (ret == -EBUSY); @@ -659,6 +663,16 @@ struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root BTRFS_RESERVE_NO_FLUSH, true); } +/* + * Similar to regular join but it never starts a transaction when none is + * running or after waiting for the current one to finish. + */ +struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root) +{ + return start_transaction(root, 0, TRANS_JOIN_NOSTART, + BTRFS_RESERVE_NO_FLUSH, true); +} + /* * btrfs_attach_transaction() - catch the running transaction * diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h index 527ea94b57d9..2c5a6f6e5bb0 100644 --- a/fs/btrfs/transaction.h +++ b/fs/btrfs/transaction.h @@ -94,11 +94,13 @@ struct btrfs_transaction { #define __TRANS_JOIN (1U << 11) #define __TRANS_JOIN_NOLOCK (1U << 12) #define __TRANS_DUMMY (1U << 13) +#define __TRANS_JOIN_NOSTART (1U << 14) #define TRANS_START (__TRANS_START | __TRANS_FREEZABLE) #define TRANS_ATTACH (__TRANS_ATTACH) #define TRANS_JOIN (__TRANS_JOIN | __TRANS_FREEZABLE) #define TRANS_JOIN_NOLOCK (__TRANS_JOIN_NOLOCK) +#define TRANS_JOIN_NOSTART (__TRANS_JOIN_NOSTART) #define TRANS_EXTWRITERS (__TRANS_START | __TRANS_ATTACH) @@ -183,6 +185,7 @@ struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv( int min_factor); 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_join_transaction_nostart(struct btrfs_root *root); struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root); struct btrfs_trans_handle *btrfs_attach_transaction_barrier( struct btrfs_root *root);