On Thu, Apr 25, 2019 at 12:39 AM Amir Goldstein <amir73il@xxxxxxxxx> wrote: > > 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@xxxxxxxxx/ > Reported-by: Murphy Zhou <jencce.kernel@xxxxxxxxx> > Fixes: d1d04ef8572b ("ovl: stack file ops") > Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx> > --- > > Miklos, > > V1 was addressed to Jan and was trying to teach fsnotify about fake path. > V2 leaves fsnotify subsystem alone and just sets the FMODE_NONOTIFY > flag on realfile. All the rest of the complications with mark mounts > are irrelevant. > > Same extended fanotify06 that was used to verify V1 also verified V2. Thanks for fixing this! My overlayfs tests on this patch looks good. M > > Thanks, > Amir. > > fs/overlayfs/file.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c > index ddfd93f13cc5..7d2f01957e40 100644 > --- a/fs/overlayfs/file.c > +++ b/fs/overlayfs/file.c > @@ -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)) > -- > 2.17.1 >
