From d0c97d52f5e1de125394d748be7bd5763fd9ed9e Mon Sep 17 00:00:00 2001 From: Xue jiufei Date: Fri, 4 Sep 2015 15:44:48 -0700 Subject: [PATCH] ocfs2: do not set fs read-only if rec[0] is empty while committing truncate While appending an extent to a file, it will call these functions: ocfs2_insert_extent -> call ocfs2_grow_tree() if there's no free rec -> ocfs2_add_branch add a new branch to extent tree, now rec[0] in the leaf of rightmost path is empty -> ocfs2_do_insert_extent -> ocfs2_rotate_tree_right -> ocfs2_extend_rotate_transaction -> jbd2_journal_restart if jbd2_journal_extend fail -> ocfs2_insert_path -> ocfs2_extend_trans -> jbd2_journal_restart if jbd2_journal_extend fail -> ocfs2_insert_at_leaf -> ocfs2_et_update_clusters Function jbd2_journal_restart() may be called and it may happened that buffers dirtied in ocfs2_add_branch() are committed while buffers dirtied in ocfs2_insert_at_leaf() and ocfs2_et_update_clusters() are not. So an empty rec[0] is left in rightmost path which will cause read-only filesystem when call ocfs2_commit_truncate() with the error message: "Inode %lu has an empty extent record". This is not a serious problem, so remove the rightmost path when call ocfs2_commit_truncate(). Signed-off-by: joyce.xue Reviewed-by: Mark Fasheh Cc: Joel Becker Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ocfs2/alloc.c | 44 ++++++++++++++++++++++++++++++++++++++------ 1 file changed, 38 insertions(+), 6 deletions(-) diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c index 9a0fd494fe74..77cbd1e3c950 100644 --- a/fs/ocfs2/alloc.c +++ b/fs/ocfs2/alloc.c @@ -3131,6 +3131,30 @@ static int ocfs2_remove_rightmost_path(handle_t *handle, return ret; } +static int ocfs2_remove_rightmost_empty_extent(struct ocfs2_super *osb, + struct ocfs2_extent_tree *et, + struct ocfs2_path *path, + struct ocfs2_cached_dealloc_ctxt *dealloc) +{ + handle_t *handle; + int ret; + int credits = path->p_tree_depth * 2 + 1; + + handle = ocfs2_start_trans(osb, credits); + if (IS_ERR(handle)) { + ret = PTR_ERR(handle); + mlog_errno(ret); + return ret; + } + + ret = ocfs2_remove_rightmost_path(handle, et, path, dealloc); + if (ret) + mlog_errno(ret); + + ocfs2_commit_trans(osb, handle); + return ret; +} + /* * Left rotation of btree records. * @@ -7108,15 +7132,23 @@ int ocfs2_commit_truncate(struct ocfs2_super *osb, * to check it up here before changing the tree. */ if (root_el->l_tree_depth && rec->e_int_clusters == 0) { - ocfs2_error(inode->i_sb, "Inode %lu has an empty " + mlog(ML_ERROR, "Inode %lu has an empty " "extent record, depth %u\n", inode->i_ino, le16_to_cpu(root_el->l_tree_depth)); - status = -EROFS; - goto bail; + status = ocfs2_remove_rightmost_empty_extent(osb, + &et, path, &dealloc); + if (status) { + mlog_errno(status); + goto bail; + } + + ocfs2_reinit_path(path, 1); + goto start; + } else { + trunc_cpos = le32_to_cpu(rec->e_cpos); + trunc_len = 0; + blkno = 0; } - trunc_cpos = le32_to_cpu(rec->e_cpos); - trunc_len = 0; - blkno = 0; } else if (le32_to_cpu(rec->e_cpos) >= new_highest_cpos) { /* * Truncate entire record. -- GitLab