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(-)
--- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -32,13 +32,16 @@ static char ovl_whatisit(struct inode *i 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, @@ -59,8 +62,7 @@ static int ovl_change_flags(struct file 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)) @@ -113,7 +115,7 @@ static int ovl_real_fdget_meta(const str }
/* 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;