[PATCH] UBIFS: Add log overlap assertions

[hujianyang <hujianyang@huawei.com>]

We use a circle area to record log node in ubifs. This log area
should not be overlapped. But after researching the code, I found
some condition may lead log head wrap log ltail. Although we've
fixed the problems discovered, there may be some other issues still
left.

This patch adds assertions when lhead changes to next leb to make
sure ltail is not wrapped.


Signed-off-by: hujianyang <hujianyang@huawei.com>
---
 fs/ubifs/log.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/ubifs/log.c b/fs/ubifs/log.c
index 7e818ec..c14628f 100644
--- a/fs/ubifs/log.c
+++ b/fs/ubifs/log.c
@@ -244,6 +244,7 @@ int ubifs_add_bud_to_log(struct ubifs_info *c, int jhead, int lnum, int offs)

        if (c->lhead_offs > c->leb_size - c->ref_node_alsz) {
                c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
+               ubifs_assert(c->lhead_lnum != c->ltail_lnum);
                c->lhead_offs = 0;
        }

@@ -408,6 +409,7 @@ int ubifs_log_start_commit(struct ubifs_info *c, int *ltail_lnum)
        /* Switch to the next log LEB */
        if (c->lhead_offs) {
                c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
+               ubifs_assert(c->lhead_lnum != c->ltail_lnum);
                c->lhead_offs = 0;
        }

-- 
1.8.1.4