From: Amir Goldstein <amir73il@gmail.com> 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: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- fs/overlayfs/file.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index fa5ac5de807c..73c3e2c21edb 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -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; -- 2.25.1