Re: [PATCH v3 14/70] nstree: allow lookup solely based on inode
From: Jeff Layton <jlayton@kernel.org>
Date: 2025-10-27 13:48:18
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On Fri, 2025-10-24 at 12:52 +0200, Christian Brauner wrote:
The namespace file handle struct nsfs_file_handle is uapi and userspace is expressly allowed to generate file handles without going through name_to_handle_at(). Allow userspace to generate a file handle where both the inode number and the namespace type are zero and just pass in the unique namespace id. The kernel uses the unified namespace tree to find the namespace and open the file handle. When the kernel creates a file handle via name_to_handle_at() it will always fill in the type and the inode number allowing userspace to retrieve core information.
Where is the nsfs filehandle format documented? I didn't see any reference to it in the manpages.
quoted hunk ↗ jump to hunk
Signed-off-by: Christian Brauner <brauner@kernel.org> --- fs/nsfs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)diff --git a/fs/nsfs.c b/fs/nsfs.c index 8b9bebd11c49..19dc28742a42 100644 --- a/fs/nsfs.c +++ b/fs/nsfs.c@@ -502,8 +502,8 @@ static struct dentry *nsfs_fh_to_dentry(struct super_block *sb, struct fid *fh, return NULL; VFS_WARN_ON_ONCE(ns->ns_id != fid->ns_id); - VFS_WARN_ON_ONCE(ns->ns_type != fid->ns_type); - VFS_WARN_ON_ONCE(ns->inum != fid->ns_inum); + if (fid->ns_inum && (fid->ns_inum != ns->inum)) + return NULL; /* * This is racy because we're not actually taking an
-- Jeff Layton [off-list ref]