5cffa333a2
commit 5b0a414d06c3ed2097e32ef7944a4abb644b89bd upstream.
This regression can be reproduced with ntfs-3g and overlayfs:
mkdir lower upper work overlay
dd if=/dev/zero of=ntfs.raw bs=1M count=2
mkntfs -F ntfs.raw
mount ntfs.raw lower
touch lower/file.txt
mount -t overlay -o lowerdir=lower,upperdir=upper,workdir=work - overlay
mv overlay/file.txt overlay/file2.txt
mv fails and (misleadingly) prints
mv: cannot move 'overlay/file.txt' to a subdirectory of itself, 'overlay/file2.txt'
The reason is that ovl_copy_fileattr() is triggered due to S_NOATIME being
set on all inodes (by fuse) regardless of fileattr.
ovl_copy_fileattr() tries to retrieve file attributes from lower file, but
that fails because filesystem does not support this ioctl (this should fail
with ENOTTY, but ntfs-3g return EINVAL instead). This failure is
propagated to origial operation (in this case rename) that triggered the
copy-up.
The fix is to ignore ENOTTY and EINVAL errors from fileattr_get() in copy
up. This also requires turning the internal ENOIOCTLCMD into ENOTTY.
As a further measure to prevent unnecessary failures, only try the
fileattr_get/set on upper if there are any flags to copy up.
Side note: a number of filesystems set S_NOATIME (and sometimes other inode
flags) irrespective of fileattr flags. This causes unnecessary calls
during copy up, which might lead to a performance issue, especially if
latency is high. To fix this, the kernel would need to differentiate
between the two cases. E.g. introduce SB_NOATIME_UPDATE, a per-sb variant
of S_NOATIME. SB_NOATIME doesn't work, because that's interpreted as
"filesystem doesn't store an atime attribute"
Reported-and-tested-by: Kevin Locke <kevin@kevinlocke.name>
Fixes: 72db82115d2b ("ovl: copy up sync/noatime fileattr flags")
Cc: <stable@vger.kernel.org> # v5.15
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.