overlayfs: don't hold ->i_mutex over opening the real directory

just use it to serialize the assignment

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2014-10-23 22:56:05 -04:00
parent 1be47b387a
commit 3d268c9b13

View File

@ -458,21 +458,28 @@ static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
if (!od->is_upper && ovl_path_type(dentry) == OVL_PATH_MERGE) {
struct inode *inode = file_inode(file);
mutex_lock(&inode->i_mutex);
realfile = od->upperfile;
if (!realfile) {
struct path upperpath;
ovl_path_upper(dentry, &upperpath);
realfile = ovl_path_open(&upperpath, O_RDONLY);
mutex_lock(&inode->i_mutex);
if (!od->upperfile) {
if (IS_ERR(realfile)) {
mutex_unlock(&inode->i_mutex);
return PTR_ERR(realfile);
}
od->upperfile = realfile;
} else {
/* somebody has beaten us to it */
if (!IS_ERR(realfile))
fput(realfile);
realfile = od->upperfile;
}
mutex_unlock(&inode->i_mutex);
}
}
return vfs_fsync_range(realfile, start, end, datasync);
}