ovl: do not generate duplicate fsnotify events for "fake" path (d9899030) · Commits · 戴 / test

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: ("ovl: stack file ops") Signed-off-by:

Amir Goldstein <amir73il@gmail.com> Signed-off-by:

Miklos Szeredi <mszeredi@redhat.com>

fs/overlayfs/file.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -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))

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