ovl: do not generate duplicate fsnotify events for "fake" path

Overlayfs "fake" path is used for stacked file operations on underlying
files.  Operations on files with "fake" path must not generate fsnotify
events with path data, because those events have already been generated at
overlayfs layer and because the reported event->fd for fanotify marks on
underlying inode/filesystem will have the wrong path (the overlayfs path).

Link: https://lore.kernel.org/linux-fsdevel/20190423065024.12695-1-jencce.kernel@gmail.com/
Reported-by: Murphy Zhou <jencce.kernel@gmail.com>
Fixes: d1d04ef857 ("ovl: stack file ops")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Amir Goldstein 2019-04-24 19:39:50 +03:00 committed by Miklos Szeredi
parent 9e46b840c7
commit d989903058

View File

@ -29,10 +29,11 @@ static struct file *ovl_open_realfile(const struct file *file,
struct inode *inode = file_inode(file);
struct file *realfile;
const struct cred *old_cred;
int flags = file->f_flags | O_NOATIME | FMODE_NONOTIFY;
old_cred = ovl_override_creds(inode->i_sb);
realfile = open_with_fake_path(&file->f_path, file->f_flags | O_NOATIME,
realinode, current_cred());
realfile = open_with_fake_path(&file->f_path, flags, realinode,
current_cred());
revert_creds(old_cred);
pr_debug("open(%p[%pD2/%c], 0%o) -> (%p, 0%o)\n",
@ -50,7 +51,7 @@ static int ovl_change_flags(struct file *file, unsigned int flags)
int err;
/* No atime modificaton on underlying */
flags |= O_NOATIME;
flags |= O_NOATIME | FMODE_NONOTIFY;
/* If some flag changed that cannot be changed then something's amiss */
if (WARN_ON((file->f_flags ^ flags) & ~OVL_SETFL_MASK))