commit ee70999a988b8abc3490609142f50ebaa8344432 upstream. Patch series "nilfs2: fix issues with rename operations". This series fixes BUG_ON check failures reported by syzbot around rename operations, and a minor behavioral issue where the mtime of a child directory changes when it is renamed instead of moved. This patch (of 2): The directory manipulation routines nilfs_set_link() and nilfs_delete_entry() rewrite the directory entry in the folio/page previously read by nilfs_find_entry(), so error handling is omitted on the assumption that nilfs_prepare_chunk(), which prepares the buffer for rewriting, will always succeed for these. And if an error is returned, it triggers the legacy BUG_ON() checks in each routine. This assumption is wrong, as proven by syzbot: the buffer layer called by nilfs_prepare_chunk() may call nilfs_get_block() if necessary, which may fail due to metadata corruption or other reasons. This has been there all along, but improved sanity checks and error handling may have made it more reproducible in fuzzing tests. Fix this issue by adding missing error paths in nilfs_set_link(), nilfs_delete_entry(), and their caller nilfs_rename(). [konishi.ryusuke@xxxxxxxxx: adjusted for page/folio conversion] Link: https://lkml.kernel.org/r/20250111143518.7901-1-konishi.ryusuke@xxxxxxxxx Link: https://lkml.kernel.org/r/20250111143518.7901-2-konishi.ryusuke@xxxxxxxxx Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx> Reported-by: syzbot+32c3706ebf5d95046ea1@xxxxxxxxxxxxxxxxxxxxxxxxx Closes: https://syzkaller.appspot.com/bug?extid=32c3706ebf5d95046ea1 Reported-by: syzbot+1097e95f134f37d9395c@xxxxxxxxxxxxxxxxxxxxxxxxx Closes: https://syzkaller.appspot.com/bug?extid=1097e95f134f37d9395c Fixes: 2ba466d74ed7 ("nilfs2: directory entry operations") Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/nilfs2/dir.c | 13 ++++++++++--- fs/nilfs2/namei.c | 29 +++++++++++++++-------------- fs/nilfs2/nilfs.h | 4 ++-- 3 files changed, 27 insertions(+), 19 deletions(-) diff --git a/fs/nilfs2/dir.c b/fs/nilfs2/dir.c index c6dd8ef7d284..49ca762baa8f 100644 --- a/fs/nilfs2/dir.c +++ b/fs/nilfs2/dir.c @@ -444,7 +444,7 @@ int nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr, ino_t *ino) return 0; } -void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de, +int nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de, struct page *page, struct inode *inode) { unsigned int from = (char *)de - (char *)page_address(page); @@ -454,11 +454,15 @@ void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de, lock_page(page); err = nilfs_prepare_chunk(page, from, to); - BUG_ON(err); + if (unlikely(err)) { + unlock_page(page); + return err; + } de->inode = cpu_to_le64(inode->i_ino); nilfs_set_de_type(de, inode); nilfs_commit_chunk(page, mapping, from, to); dir->i_mtime = inode_set_ctime_current(dir); + return 0; } /* @@ -590,7 +594,10 @@ int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct page *page) from = (char *)pde - (char *)page_address(page); lock_page(page); err = nilfs_prepare_chunk(page, from, to); - BUG_ON(err); + if (unlikely(err)) { + unlock_page(page); + goto out; + } if (pde) pde->rec_len = nilfs_rec_len_to_disk(to - from); dir->inode = 0; diff --git a/fs/nilfs2/namei.c b/fs/nilfs2/namei.c index 4d60ccdd85f3..43f01fe556fe 100644 --- a/fs/nilfs2/namei.c +++ b/fs/nilfs2/namei.c @@ -406,8 +406,10 @@ static int nilfs_rename(struct mnt_idmap *idmap, err = PTR_ERR(new_de); goto out_dir; } - nilfs_set_link(new_dir, new_de, new_page, old_inode); + err = nilfs_set_link(new_dir, new_de, new_page, old_inode); nilfs_put_page(new_page); + if (unlikely(err)) + goto out_dir; nilfs_mark_inode_dirty(new_dir); inode_set_ctime_current(new_inode); if (dir_de) @@ -430,28 +432,27 @@ static int nilfs_rename(struct mnt_idmap *idmap, */ inode_set_ctime_current(old_inode); - nilfs_delete_entry(old_de, old_page); - - if (dir_de) { - nilfs_set_link(old_inode, dir_de, dir_page, new_dir); - nilfs_put_page(dir_page); - drop_nlink(old_dir); + err = nilfs_delete_entry(old_de, old_page); + if (likely(!err)) { + if (dir_de) { + err = nilfs_set_link(old_inode, dir_de, dir_page, + new_dir); + drop_nlink(old_dir); + } + nilfs_mark_inode_dirty(old_dir); } - nilfs_put_page(old_page); - - nilfs_mark_inode_dirty(old_dir); nilfs_mark_inode_dirty(old_inode); - err = nilfs_transaction_commit(old_dir->i_sb); - return err; - out_dir: if (dir_de) nilfs_put_page(dir_page); out_old: nilfs_put_page(old_page); out: - nilfs_transaction_abort(old_dir->i_sb); + if (likely(!err)) + err = nilfs_transaction_commit(old_dir->i_sb); + else + nilfs_transaction_abort(old_dir->i_sb); return err; } diff --git a/fs/nilfs2/nilfs.h b/fs/nilfs2/nilfs.h index fbf74c1cfd1d..4c4b76865484 100644 --- a/fs/nilfs2/nilfs.h +++ b/fs/nilfs2/nilfs.h @@ -240,8 +240,8 @@ nilfs_find_entry(struct inode *, const struct qstr *, struct page **); extern int nilfs_delete_entry(struct nilfs_dir_entry *, struct page *); extern int nilfs_empty_dir(struct inode *); extern struct nilfs_dir_entry *nilfs_dotdot(struct inode *, struct page **); -extern void nilfs_set_link(struct inode *, struct nilfs_dir_entry *, - struct page *, struct inode *); +int nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de, + struct page *page, struct inode *inode); static inline void nilfs_put_page(struct page *page) { -- 2.43.5
