[PATCH 4.2.y-ckt 77/98] jffs2: reduce the breakage on recovery from halfway failed rename()

From: Kamal Mostafa
Date: Tue Mar 15 2016 - 19:33:57 EST


4.2.8-ckt6 -stable review patch. If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

commit f93812846f31381d35c04c6c577d724254355e7f upstream.

d_instantiate(new_dentry, old_inode) is absolutely wrong thing to
do - it will oops if new_dentry used to be positive, for starters.
What we need is d_invalidate() the target and be done with that.

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
fs/jffs2/dir.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c
index 8118002..da37f2e 100644
--- a/fs/jffs2/dir.c
+++ b/fs/jffs2/dir.c
@@ -846,9 +846,14 @@ static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,

pr_notice("%s(): Link succeeded, unlink failed (err %d). You now have a hard link\n",
__func__, ret);
- /* Might as well let the VFS know */
- d_instantiate(new_dentry, d_inode(old_dentry));
- ihold(d_inode(old_dentry));
+ /*
+ * We can't keep the target in dcache after that.
+ * For one thing, we can't afford dentry aliases for directories.
+ * For another, if there was a victim, we _can't_ set new inode
+ * for that sucker and we have to trigger mount eviction - the
+ * caller won't do it on its own since we are returning an error.
+ */
+ d_invalidate(new_dentry);
new_dir_i->i_mtime = new_dir_i->i_ctime = ITIME(now);
return ret;
}
--
2.7.0