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Tue, 16 Apr 2019 07:48:18 +0000 (UTC) Subject: Re: [PATCH 3/3] btrfs-progs: Handle error properly in btrfs_commit_transaction() To: Qu Wenruo , linux-btrfs@vger.kernel.org References: <20190416071526.3576-1-wqu@suse.com> <20190416071526.3576-4-wqu@suse.com> From: Nikolay Borisov Openpgp: preference=signencrypt Autocrypt: addr=nborisov@suse.com; prefer-encrypt=mutual; keydata= mQINBFiKBz4BEADNHZmqwhuN6EAzXj9SpPpH/nSSP8YgfwoOqwrP+JR4pIqRK0AWWeWCSwmZ T7g+RbfPFlmQp+EwFWOtABXlKC54zgSf+uulGwx5JAUFVUIRBmnHOYi/lUiE0yhpnb1KCA7f u/W+DkwGerXqhhe9TvQoGwgCKNfzFPZoM+gZrm+kWv03QLUCr210n4cwaCPJ0Nr9Z3c582xc bCUVbsjt7BN0CFa2BByulrx5xD9sDAYIqfLCcZetAqsTRGxM7LD0kh5WlKzOeAXj5r8DOrU2 GdZS33uKZI/kZJZVytSmZpswDsKhnGzRN1BANGP8sC+WD4eRXajOmNh2HL4P+meO1TlM3GLl EQd2shHFY0qjEo7wxKZI1RyZZ5AgJnSmehrPCyuIyVY210CbMaIKHUIsTqRgY5GaNME24w7h TyyVCy2qAM8fLJ4Vw5bycM/u5xfWm7gyTb9V1TkZ3o1MTrEsrcqFiRrBY94Rs0oQkZvunqia c+NprYSaOG1Cta14o94eMH271Kka/reEwSZkC7T+o9hZ4zi2CcLcY0DXj0qdId7vUKSJjEep c++s8ncFekh1MPhkOgNj8pk17OAESanmDwksmzh1j12lgA5lTFPrJeRNu6/isC2zyZhTwMWs k3LkcTa8ZXxh0RfWAqgx/ogKPk4ZxOXQEZetkEyTFghbRH2BIwARAQABtCNOaWtvbGF5IEJv cmlzb3YgPG5ib3Jpc292QHN1c2UuY29tPokCOAQTAQIAIgUCWIo48QIbAwYLCQgHAwIGFQgC CQoLBBYCAwECHgECF4AACgkQcb6CRuU/KFc0eg/9GLD3wTQz9iZHMFbjiqTCitD7B6dTLV1C ddZVlC8Hm/TophPts1bWZORAmYIihHHI1EIF19+bfIr46pvfTu0yFrJDLOADMDH+Ufzsfy2v HSqqWV/nOSWGXzh8bgg/ncLwrIdEwBQBN9SDS6aqsglagvwFD91UCg/TshLlRxD5BOnuzfzI Leyx2c6YmH7Oa1R4MX9Jo79SaKwdHt2yRN3SochVtxCyafDlZsE/efp21pMiaK1HoCOZTBp5 VzrIP85GATh18pN7YR9CuPxxN0V6IzT7IlhS4Jgj0NXh6vi1DlmKspr+FOevu4RVXqqcNTSS E2rycB2v6cttH21UUdu/0FtMBKh+rv8+yD49FxMYnTi1jwVzr208vDdRU2v7Ij/TxYt/v4O8 V+jNRKy5Fevca/1xroQBICXsNoFLr10X5IjmhAhqIH8Atpz/89ItS3+HWuE4BHB6RRLM0gy8 T7rN6ja+KegOGikp/VTwBlszhvfLhyoyjXI44Tf3oLSFM+8+qG3B7MNBHOt60CQlMkq0fGXd mm4xENl/SSeHsiomdveeq7cNGpHi6i6ntZK33XJLwvyf00PD7tip/GUj0Dic/ZUsoPSTF/mG EpuQiUZs8X2xjK/AS/l3wa4Kz2tlcOKSKpIpna7V1+CMNkNzaCOlbv7QwprAerKYywPCoOSC 7P25Ag0EWIoHPgEQAMiUqvRBZNvPvki34O/dcTodvLSyOmK/MMBDrzN8Cnk302XfnGlW/YAQ csMWISKKSpStc6tmD+2Y0z9WjyRqFr3EGfH1RXSv9Z1vmfPzU42jsdZn667UxrRcVQXUgoKg QYx055Q2FdUeaZSaivoIBD9WtJq/66UPXRRr4H/+Y5FaUZx+gWNGmBT6a0S/GQnHb9g3nonD jmDKGw+YO4P6aEMxyy3k9PstaoiyBXnzQASzdOi39BgWQuZfIQjN0aW+Dm8kOAfT5i/yk59h VV6v3NLHBjHVw9kHli3jwvsizIX9X2W8tb1SefaVxqvqO1132AO8V9CbE1DcVT8fzICvGi42 FoV/k0QOGwq+LmLf0t04Q0csEl+h69ZcqeBSQcIMm/Ir+NorfCr6HjrB6lW7giBkQl6hhomn l1mtDP6MTdbyYzEiBFcwQD4terc7S/8ELRRybWQHQp7sxQM/Lnuhs77MgY/e6c5AVWnMKd/z MKm4ru7A8+8gdHeydrRQSWDaVbfy3Hup0Ia76J9FaolnjB8YLUOJPdhI2vbvNCQ2ipxw3Y3c KhVIpGYqwdvFIiz0Fej7wnJICIrpJs/+XLQHyqcmERn3s/iWwBpeogrx2Lf8AGezqnv9woq7 OSoWlwXDJiUdaqPEB/HmGfqoRRN20jx+OOvuaBMPAPb+aKJyle8zABEBAAGJAh8EGAECAAkF AliKBz4CGwwACgkQcb6CRuU/KFdacg/+M3V3Ti9JYZEiIyVhqs+yHb6NMI1R0kkAmzsGQ1jU zSQUz9AVMR6T7v2fIETTT/f5Oout0+Hi9cY8uLpk8CWno9V9eR/B7Ifs2pAA8lh2nW43FFwp IDiSuDbH6oTLmiGCB206IvSuaQCp1fed8U6yuqGFcnf0ZpJm/sILG2ECdFK9RYnMIaeqlNQm iZicBY2lmlYFBEaMXHoy+K7nbOuizPWdUKoKHq+tmZ3iA+qL5s6Qlm4trH28/fPpFuOmgP8P K+7LpYLNSl1oQUr+WlqilPAuLcCo5Vdl7M7VFLMq4xxY/dY99aZx0ZJQYFx0w/6UkbDdFLzN upT7NIN68lZRucImffiWyN7CjH23X3Tni8bS9ubo7OON68NbPz1YIaYaHmnVQCjDyDXkQoKC R82Vf9mf5slj0Vlpf+/Wpsv/TH8X32ajva37oEQTkWNMsDxyw3aPSps6MaMafcN7k60y2Wk/ TCiLsRHFfMHFY6/lq/c0ZdOsGjgpIK0G0z6et9YU6MaPuKwNY4kBdjPNBwHreucrQVUdqRRm RcxmGC6ohvpqVGfhT48ZPZKZEWM+tZky0mO7bhZYxMXyVjBn4EoNTsXy1et9Y1dU3HVJ8fod 5UqrNrzIQFbdeM0/JqSLrtlTcXKJ7cYFa9ZM2AP7UIN9n1UWxq+OPY9YMOewVfYtL8M= Message-ID: Date: Tue, 16 Apr 2019 10:48:17 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190416071526.3576-4-wqu@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 16.04.19 г. 10:15 ч., Qu Wenruo wrote: > [BUG] > When running fuzz-tests/003 and fuzz-tests/009, btrfs-progs will crash > due to BUG_ON(). > > [CAUSE] > We abused BUG_ON() in btrfs_commit_transaction(), which is one of the > most error prone function for fuzzed images. > > Currently to cleanup the aborted transaction, we only need to clean up > the only per-transaction data: delayed refs. > > This patch will introduce a new function, btrfs_destroy_delayed_refs() > to cleanup delayed refs when we failed to commit transaction. > > With that function, we will gently destroy per-trans delayed ref, and > remove the BUG_ON()s in btrfs_commit_transaction(). > > Signed-off-by: Qu Wenruo Reviewed-by: Nikolay Borisov Though see below for a suggestion of further cleanup > --- > delayed-ref.c | 24 ++++++++++++++++++++++++ > delayed-ref.h | 5 +++++ > extent-tree.c | 6 +++--- > transaction.c | 20 ++++++++++++++------ > 4 files changed, 46 insertions(+), 9 deletions(-) > > diff --git a/delayed-ref.c b/delayed-ref.c > index 9974dbbd4c6b..69f8be34fe18 100644 > --- a/delayed-ref.c > +++ b/delayed-ref.c > @@ -605,3 +605,27 @@ free_ref: > > return -ENOMEM; > } > + > +void btrfs_destroy_delayed_refs(struct btrfs_trans_handle *trans) > +{ > + struct btrfs_fs_info *fs_info = trans->fs_info; > + struct rb_node *node; > + struct btrfs_delayed_ref_root *delayed_refs; > + > + delayed_refs = &trans->delayed_refs; > + if (RB_EMPTY_ROOT(&delayed_refs->href_root)) > + return; > + while ((node = rb_first(&delayed_refs->href_root)) != NULL) { > + struct btrfs_delayed_ref_head *head; > + struct btrfs_delayed_ref_node *ref; > + struct rb_node *n; > + > + head = rb_entry(node, struct btrfs_delayed_ref_head, href_node); > + while ((n = rb_first(&head->ref_tree)) != NULL) { > + ref = rb_entry(n, struct btrfs_delayed_ref_node, > + ref_node); > + drop_delayed_ref(trans, delayed_refs, head, ref); > + } > + ASSERT(cleanup_ref_head(trans, fs_info, head) == 0); > + } > +} > diff --git a/delayed-ref.h b/delayed-ref.h > index 30a68b2a278c..4ff3eaa929ba 100644 > --- a/delayed-ref.h > +++ b/delayed-ref.h > @@ -205,4 +205,9 @@ btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node) > { > return container_of(node, struct btrfs_delayed_tree_ref, node); > } > + > +int cleanup_ref_head(struct btrfs_trans_handle *trans, > + struct btrfs_fs_info *fs_info, > + struct btrfs_delayed_ref_head *head); > +void btrfs_destroy_delayed_refs(struct btrfs_trans_handle *trans); > #endif > diff --git a/extent-tree.c b/extent-tree.c > index 1140ebfc61ff..e62ee8c2ba13 100644 > --- a/extent-tree.c > +++ b/extent-tree.c > @@ -4085,9 +4085,9 @@ static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_ref > delayed_refs->num_heads_ready++; > } > > -static int cleanup_ref_head(struct btrfs_trans_handle *trans, > - struct btrfs_fs_info *fs_info, > - struct btrfs_delayed_ref_head *head) > +int cleanup_ref_head(struct btrfs_trans_handle *trans, > + struct btrfs_fs_info *fs_info, > + struct btrfs_delayed_ref_head *head) You can create a followup patch that removes the fs_info argument from cleanup_ref_head to make it identical to the kernel version. > { > struct btrfs_delayed_ref_root *delayed_refs; > > diff --git a/transaction.c b/transaction.c > index 8d15eb11c7b5..138e10f0d6cc 100644 > --- a/transaction.c > +++ b/transaction.c > @@ -17,6 +17,7 @@ > #include "kerncompat.h" > #include "disk-io.h" > #include "transaction.h" > +#include "delayed-ref.h" > > #include "messages.h" > > @@ -165,7 +166,8 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, > * consistent > */ > ret = btrfs_run_delayed_refs(trans, -1); > - BUG_ON(ret); > + if (ret < 0) > + goto error; > > if (root->commit_root == root->node) > goto commit_tree; > @@ -182,21 +184,24 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, > root->root_item.level = btrfs_header_level(root->node); > ret = btrfs_update_root(trans, root->fs_info->tree_root, > &root->root_key, &root->root_item); > - BUG_ON(ret); > + if (ret < 0) > + goto error; > > commit_tree: > ret = commit_tree_roots(trans, fs_info); > - BUG_ON(ret); > + if (ret < 0) > + goto error; > /* > * Ensure that all committed roots are properly accounted in the > * extent tree > */ > ret = btrfs_run_delayed_refs(trans, -1); > - BUG_ON(ret); > + if (ret < 0) > + goto error; > btrfs_write_dirty_block_groups(trans); > __commit_transaction(trans, root); > if (ret < 0) > - goto out; > + goto error; > ret = write_ctree_super(trans); > btrfs_finish_extent_commit(trans); > kfree(trans); > @@ -204,7 +209,10 @@ commit_tree: > root->commit_root = NULL; > fs_info->running_transaction = NULL; > fs_info->last_trans_committed = transid; > -out: > + return ret; > +error: > + btrfs_destroy_delayed_refs(trans); > + free(trans); > return ret; > } > >