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Commit 00de23f4 authored by Amir Goldstein's avatar Amir Goldstein Committed by Greg Kroah-Hartman
Browse files

ovl: fix unneeded call to ovl_change_flags() 



commit 81a33c1ee941c3bb9ffc6bac8f676be13351344e upstream.

The check if user has changed the overlay file was wrong, causing unneeded
call to ovl_change_flags() including taking f_lock on every file access.

Fixes: d989903058a8 ("ovl: do not generate duplicate fsnotify events for "fake" path")
Cc: <stable@vger.kernel.org> # v4.19+
Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f03b3a03

fs/overlayfs/file.c

+6 −4
Original line number Diff line number Diff line
@@ -24,13 +24,16 @@ static char ovl_whatisit(struct inode *inode, struct inode *realinode) 
		return 'm';

}



/* No atime modificaton nor notify on underlying */

#define OVL_OPEN_FLAGS (O_NOATIME | FMODE_NONOTIFY)



static struct file *ovl_open_realfile(const struct file *file,

				      struct inode *realinode)

{

	struct inode *inode = file_inode(file);

	struct file *realfile;

	const struct cred *old_cred;

	int flags = file->f_flags | O_NOATIME | FMODE_NONOTIFY;

	int flags = file->f_flags | OVL_OPEN_FLAGS;



	old_cred = ovl_override_creds(inode->i_sb);

	realfile = open_with_fake_path(&file->f_path, flags, realinode,
@@ -51,8 +54,7 @@ static int ovl_change_flags(struct file *file, unsigned int flags) 
	struct inode *inode = file_inode(file);

	int err;



	/* No atime modificaton on underlying */

	flags |= O_NOATIME | FMODE_NONOTIFY;

	flags |= OVL_OPEN_FLAGS;



	/* If some flag changed that cannot be changed then something's amiss */

	if (WARN_ON((file->f_flags ^ flags) & ~OVL_SETFL_MASK))
@@ -105,7 +107,7 @@ static int ovl_real_fdget_meta(const struct file *file, struct fd *real, 
	}



	/* Did the flags change since open? */

	if (unlikely((file->f_flags ^ real->file->f_flags) & ~O_NOATIME))

	if (unlikely((file->f_flags ^ real->file->f_flags) & ~OVL_OPEN_FLAGS))

		return ovl_change_flags(real->file, file->f_flags);



	return 0;