Xue jiufei
2015-Apr-27 02:51 UTC
[Ocfs2-devel] [PATCH 2/3] 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 at huawei.com>
---
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 286a392..ebb2cc4 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -3104,6 +3104,30 @@ out:
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.
*
@@ -7134,15 +7158,23 @@ start:
* 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.
--
1.8.4.3