diff options
| -rw-r--r-- | fs/btrfs/ioctl.c | 5 | ||||
| -rw-r--r-- | fs/btrfs/transaction.c | 24 | ||||
| -rw-r--r-- | fs/btrfs/transaction.h | 2 |
3 files changed, 27 insertions, 4 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index eef5b300b9a9..90c11ddff6e5 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -805,10 +805,7 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir, goto fail; } - spin_lock(&fs_info->trans_lock); - list_add(&pending_snapshot->list, - &trans->transaction->pending_snapshots); - spin_unlock(&fs_info->trans_lock); + trans->pending_snapshot = pending_snapshot; ret = btrfs_commit_transaction(trans); if (ret) diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index 03de89b45f27..c43bbc7f623e 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -2000,6 +2000,27 @@ static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info) btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1); } +/* + * Add a pending snapshot associated with the given transaction handle to the + * respective handle. This must be called after the transaction commit started + * and while holding fs_info->trans_lock. + * This serves to guarantee a caller of btrfs_commit_transaction() that it can + * safely free the pending snapshot pointer in case btrfs_commit_transaction() + * returns an error. + */ +static void add_pending_snapshot(struct btrfs_trans_handle *trans) +{ + struct btrfs_transaction *cur_trans = trans->transaction; + + if (!trans->pending_snapshot) + return; + + lockdep_assert_held(&trans->fs_info->trans_lock); + ASSERT(cur_trans->state >= TRANS_STATE_COMMIT_START); + + list_add(&trans->pending_snapshot->list, &cur_trans->pending_snapshots); +} + int btrfs_commit_transaction(struct btrfs_trans_handle *trans) { struct btrfs_fs_info *fs_info = trans->fs_info; @@ -2073,6 +2094,8 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans) if (cur_trans->state >= TRANS_STATE_COMMIT_START) { enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED; + add_pending_snapshot(trans); + spin_unlock(&fs_info->trans_lock); refcount_inc(&cur_trans->use_count); @@ -2163,6 +2186,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans) * COMMIT_DOING so make sure to wait for num_writers to == 1 again. */ spin_lock(&fs_info->trans_lock); + add_pending_snapshot(trans); cur_trans->state = TRANS_STATE_COMMIT_DOING; spin_unlock(&fs_info->trans_lock); wait_event(cur_trans->writer_wait, diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h index 1852ed9de7fd..9402d8d94484 100644 --- a/fs/btrfs/transaction.h +++ b/fs/btrfs/transaction.h @@ -123,6 +123,8 @@ struct btrfs_trans_handle { struct btrfs_transaction *transaction; struct btrfs_block_rsv *block_rsv; struct btrfs_block_rsv *orig_rsv; + /* Set by a task that wants to create a snapshot. */ + struct btrfs_pending_snapshot *pending_snapshot; refcount_t use_count; unsigned int type; /* |