btrfs: fix return value check of btrfs_join_transaction() The error check of btrfs_join_transaction()/btrfs_join_transaction_nolock() is added, and the mistake of the error check in several places is corrected. For more stable Btrfs, I think that we should reduce BUG_ON(). But, I think that long time is necessary for this. So, I propose this patch as a short-term solution. With this patch: - To more stable Btrfs, the part that should be corrected is clarified. - The panic isn't done by the NULL pointer reference etc. (even if BUG_ON() is increased temporarily) - The error code is returned in the place where the error can be easily returned. As a long-term plan: - BUG_ON() is reduced by using the forced-readonly framework, etc. Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 2887b8b..b36eeef 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c
@@ -1550,6 +1550,7 @@ spin_unlock(&root->fs_info->new_trans_lock); trans = btrfs_join_transaction(root, 1); + BUG_ON(IS_ERR(trans)); if (transid == trans->transid) { ret = btrfs_commit_transaction(trans, root); BUG_ON(ret); @@ -2464,10 +2465,14 @@ up_write(&root->fs_info->cleanup_work_sem); trans = btrfs_join_transaction(root, 1); + if (IS_ERR(trans)) + return PTR_ERR(trans); ret = btrfs_commit_transaction(trans, root); BUG_ON(ret); /* run commit again to drop the original snapshot */ trans = btrfs_join_transaction(root, 1); + if (IS_ERR(trans)) + return PTR_ERR(trans); btrfs_commit_transaction(trans, root); ret = btrfs_write_and_wait_transaction(NULL, root); BUG_ON(ret);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index bcf3032..98ee139 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c
@@ -7478,7 +7478,7 @@ BUG_ON(reloc_root->commit_root != NULL); while (1) { trans = btrfs_join_transaction(root, 1); - BUG_ON(!trans); + BUG_ON(IS_ERR(trans)); mutex_lock(&root->fs_info->drop_mutex); ret = btrfs_drop_snapshot(trans, reloc_root);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 2b7d251..40fee13 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c
@@ -416,7 +416,7 @@ } if (start == 0) { trans = btrfs_join_transaction(root, 1); - BUG_ON(!trans); + BUG_ON(IS_ERR(trans)); btrfs_set_trans_block_group(trans, inode); trans->block_rsv = &root->fs_info->delalloc_block_rsv; @@ -612,6 +612,7 @@ GFP_NOFS); trans = btrfs_join_transaction(root, 1); + BUG_ON(IS_ERR(trans)); ret = btrfs_reserve_extent(trans, root, async_extent->compressed_size, async_extent->compressed_size, @@ -771,7 +772,7 @@ BUG_ON(root == root->fs_info->tree_root); trans = btrfs_join_transaction(root, 1); - BUG_ON(!trans); + BUG_ON(IS_ERR(trans)); btrfs_set_trans_block_group(trans, inode); trans->block_rsv = &root->fs_info->delalloc_block_rsv; @@ -1049,7 +1050,7 @@ } else { trans = btrfs_join_transaction(root, 1); } - BUG_ON(!trans); + BUG_ON(IS_ERR(trans)); cow_start = (u64)-1; cur_offset = start; @@ -1704,7 +1705,7 @@ trans = btrfs_join_transaction_nolock(root, 1); else trans = btrfs_join_transaction(root, 1); - BUG_ON(!trans); + BUG_ON(IS_ERR(trans)); btrfs_set_trans_block_group(trans, inode); trans->block_rsv = &root->fs_info->delalloc_block_rsv; ret = btrfs_update_inode(trans, root, inode); @@ -1721,6 +1722,7 @@ trans = btrfs_join_transaction_nolock(root, 1); else trans = btrfs_join_transaction(root, 1); + BUG_ON(IS_ERR(trans)); btrfs_set_trans_block_group(trans, inode); trans->block_rsv = &root->fs_info->delalloc_block_rsv; @@ -2382,6 +2384,7 @@ if (root->orphan_block_rsv || root->orphan_item_inserted) { trans = btrfs_join_transaction(root, 1); + BUG_ON(IS_ERR(trans)); btrfs_end_transaction(trans, root); } @@ -4350,6 +4353,8 @@ trans = btrfs_join_transaction_nolock(root, 1); else trans = btrfs_join_transaction(root, 1); + if (IS_ERR(trans)) + return PTR_ERR(trans); btrfs_set_trans_block_group(trans, inode); if (nolock) ret = btrfs_end_transaction_nolock(trans, root); @@ -4375,6 +4380,7 @@ return; trans = btrfs_join_transaction(root, 1); + BUG_ON(IS_ERR(trans)); btrfs_set_trans_block_group(trans, inode); ret = btrfs_update_inode(trans, root, inode); @@ -5179,6 +5185,8 @@ em = NULL; btrfs_release_path(root, path); trans = btrfs_join_transaction(root, 1); + if (IS_ERR(trans)) + return ERR_CAST(trans); goto again; } map = kmap(page); @@ -5283,8 +5291,8 @@ btrfs_drop_extent_cache(inode, start, start + len - 1, 0); trans = btrfs_join_transaction(root, 0); - if (!trans) - return ERR_PTR(-ENOMEM); + if (IS_ERR(trans)) + return ERR_CAST(trans); trans->block_rsv = &root->fs_info->delalloc_block_rsv; @@ -5508,7 +5516,7 @@ * while we look for nocow cross refs */ trans = btrfs_join_transaction(root, 0); - if (!trans) + if (IS_ERR(trans)) goto must_cow; if (can_nocow_odirect(trans, inode, start, len) == 1) { @@ -5643,7 +5651,7 @@ BUG_ON(!ordered); trans = btrfs_join_transaction(root, 1); - if (!trans) { + if (IS_ERR(trans)) { err = -ENOMEM; goto out; }
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index edd82be..04b4fb9 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c
@@ -203,7 +203,7 @@ trans = btrfs_join_transaction(root, 1); - BUG_ON(!trans); + BUG_ON(IS_ERR(trans)); ret = btrfs_update_inode(trans, root, inode); BUG_ON(ret);
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 045c9c2..ea99654 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c
@@ -2147,6 +2147,12 @@ } trans = btrfs_join_transaction(rc->extent_root, 1); + if (IS_ERR(trans)) { + if (!err) + btrfs_block_rsv_release(rc->extent_root, + rc->block_rsv, num_bytes); + return PTR_ERR(trans); + } if (!err) { if (num_bytes != rc->merging_rsv_size) { @@ -3222,6 +3228,7 @@ trans = btrfs_join_transaction(root, 0); if (IS_ERR(trans)) { btrfs_free_path(path); + ret = PTR_ERR(trans); goto out; } @@ -3628,6 +3635,7 @@ set_reloc_control(rc); trans = btrfs_join_transaction(rc->extent_root, 1); + BUG_ON(IS_ERR(trans)); btrfs_commit_transaction(trans, rc->extent_root); return 0; } @@ -3804,7 +3812,10 @@ /* get rid of pinned extents */ trans = btrfs_join_transaction(rc->extent_root, 1); - btrfs_commit_transaction(trans, rc->extent_root); + if (IS_ERR(trans)) + err = PTR_ERR(trans); + else + btrfs_commit_transaction(trans, rc->extent_root); out_free: btrfs_free_block_rsv(rc->extent_root, rc->block_rsv); btrfs_free_path(path); @@ -4125,6 +4136,11 @@ set_reloc_control(rc); trans = btrfs_join_transaction(rc->extent_root, 1); + if (IS_ERR(trans)) { + unset_reloc_control(rc); + err = PTR_ERR(trans); + goto out_free; + } rc->merge_reloc_tree = 1; @@ -4154,9 +4170,13 @@ unset_reloc_control(rc); trans = btrfs_join_transaction(rc->extent_root, 1); - btrfs_commit_transaction(trans, rc->extent_root); -out: + if (IS_ERR(trans)) + err = PTR_ERR(trans); + else + btrfs_commit_transaction(trans, rc->extent_root); +out_free: kfree(rc); +out: while (!list_empty(&reloc_roots)) { reloc_root = list_entry(reloc_roots.next, struct btrfs_root, root_list);
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index bae5c7b..3d73c8d 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c
@@ -1161,6 +1161,11 @@ INIT_DELAYED_WORK(&ac->work, do_async_commit); ac->root = root; ac->newtrans = btrfs_join_transaction(root, 0); + if (IS_ERR(ac->newtrans)) { + int err = PTR_ERR(ac->newtrans); + kfree(ac); + return err; + } /* take transaction reference */ mutex_lock(&root->fs_info->trans_mutex);