Commit d0c97d52 authored Sep 04, 2015 by Xue jiufei Committed by Linus Torvalds Sep 04, 2015

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 <xuejiufei@huawei.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 7f27ec97

fs/ocfs2/alloc.c

+38 −6

Original line number	Diff line number	Diff line
		@@ -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;
		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;
		}
		} else if (le32_to_cpu(rec->e_cpos) >= new_highest_cpos) {
		/*
		* Truncate entire record.