tentatively merged into cifs-2.6.git for-next pending additional
review and testing
On Sun, Apr 16, 2023 at 1:38 PM Paulo Alcantara <pc@xxxxxxxxxxxxx> wrote:
>
> @server->origin_fullpath already contains the tree name + optional
> prefix, so avoid calling __build_path_from_dentry_optional_prefix() as
> it might end up duplicating prefix path from @cifs_sb->prepath into
> final full path.
>
> Instead, generate DFS full path by simply merging
> @server->origin_fullpath with dentry's path.
>
> This fixes the following case
>
> mount.cifs //root/dfs/dir /mnt/ -o ...
> ls /mnt/link
>
> where cifs_dfs_do_automount() will call smb3_parse_devname() with
> @devname set to "//root/dfs/dir/link" instead of
> "//root/dfs/dir/dir/link".
>
> Fixes: 7ad54b98fc1f ("cifs: use origin fullpath for automounts")
> Signed-off-by: Paulo Alcantara (SUSE) <pc@xxxxxxxxxxxxx>
> ---
> FYI, updated DFS tests to include the above case and avoid regressions.
>
> fs/cifs/cifs_dfs_ref.c | 2 --
> fs/cifs/dfs.h | 22 ++++++++++++++++++----
> 2 files changed, 18 insertions(+), 6 deletions(-)
>
> diff --git a/fs/cifs/cifs_dfs_ref.c b/fs/cifs/cifs_dfs_ref.c
> index cb40074feb3e..0329a907bdfe 100644
> --- a/fs/cifs/cifs_dfs_ref.c
> +++ b/fs/cifs/cifs_dfs_ref.c
> @@ -171,8 +171,6 @@ static struct vfsmount *cifs_dfs_do_automount(struct path *path)
> mnt = ERR_CAST(full_path);
> goto out;
> }
> -
> - convert_delimiter(full_path, '/');
> cifs_dbg(FYI, "%s: full_path: %s\n", __func__, full_path);
>
> tmp = *cur_ctx;
> diff --git a/fs/cifs/dfs.h b/fs/cifs/dfs.h
> index 13f26e01f7b9..0b8cbf721fff 100644
> --- a/fs/cifs/dfs.h
> +++ b/fs/cifs/dfs.h
> @@ -34,19 +34,33 @@ static inline int dfs_get_referral(struct cifs_mount_ctx *mnt_ctx, const char *p
> cifs_remap(cifs_sb), path, ref, tl);
> }
>
> +/* Return DFS full path out of a dentry set for automount */
> static inline char *dfs_get_automount_devname(struct dentry *dentry, void *page)
> {
> struct cifs_sb_info *cifs_sb = CIFS_SB(dentry->d_sb);
> struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
> struct TCP_Server_Info *server = tcon->ses->server;
> + size_t len;
> + char *s;
>
> if (unlikely(!server->origin_fullpath))
> return ERR_PTR(-EREMOTE);
>
> - return __build_path_from_dentry_optional_prefix(dentry, page,
> - server->origin_fullpath,
> - strlen(server->origin_fullpath),
> - true);
> + s = dentry_path_raw(dentry, page, PATH_MAX);
> + if (IS_ERR(s))
> + return s;
> + /* for root, we want "" */
> + if (!s[1])
> + s++;
> +
> + len = strlen(server->origin_fullpath);
> + if (s < (char *)page + len)
> + return ERR_PTR(-ENAMETOOLONG);
> +
> + s -= len;
> + memcpy(s, server->origin_fullpath, len);
> + convert_delimiter(s, '/');
> + return s;
> }
>
> static inline void dfs_put_root_smb_sessions(struct list_head *head)
> --
> 2.40.0
>
--
Thanks,
Steve
