configfs_detach_prep(): make sure that wait_mutex won't go away
grab a reference to dentry we'd got the sucker from, and return
that dentry via *wait, rather than just returning the address of
->i_mutex.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index ea59c89..48929c4 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -494,7 +494,7 @@
* If there is an error, the caller will reset the flags via
* configfs_detach_rollback().
*/
-static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex)
+static int configfs_detach_prep(struct dentry *dentry, struct dentry **wait)
{
struct configfs_dirent *parent_sd = dentry->d_fsdata;
struct configfs_dirent *sd;
@@ -515,8 +515,8 @@
if (sd->s_type & CONFIGFS_USET_DEFAULT) {
/* Abort if racing with mkdir() */
if (sd->s_type & CONFIGFS_USET_IN_MKDIR) {
- if (wait_mutex)
- *wait_mutex = &d_inode(sd->s_dentry)->i_mutex;
+ if (wait)
+ *wait= dget(sd->s_dentry);
return -EAGAIN;
}
@@ -524,7 +524,7 @@
* Yup, recursive. If there's a problem, blame
* deep nesting of default_groups
*/
- ret = configfs_detach_prep(sd->s_dentry, wait_mutex);
+ ret = configfs_detach_prep(sd->s_dentry, wait);
if (!ret)
continue;
} else
@@ -1458,7 +1458,7 @@
* the new link is temporarily attached
*/
do {
- struct mutex *wait_mutex;
+ struct dentry *wait;
mutex_lock(&configfs_symlink_mutex);
spin_lock(&configfs_dirent_lock);
@@ -1469,7 +1469,7 @@
*/
ret = sd->s_dependent_count ? -EBUSY : 0;
if (!ret) {
- ret = configfs_detach_prep(dentry, &wait_mutex);
+ ret = configfs_detach_prep(dentry, &wait);
if (ret)
configfs_detach_rollback(dentry);
}
@@ -1483,8 +1483,9 @@
}
/* Wait until the racing operation terminates */
- mutex_lock(wait_mutex);
- mutex_unlock(wait_mutex);
+ inode_lock(d_inode(wait));
+ inode_unlock(d_inode(wait));
+ dput(wait);
}
} while (ret == -EAGAIN);