Re: [PATCH v5 4/7] CIFS: Use NT_CREATE_ANDX command for forcemand mounts

[Jeff Layton]

On Tue,  9 Apr 2013 16:40:24 +0400
Pavel Shilovsky  wrote:
> forcemand mount option now lets us use Windows mandatory style of
> byte-range locks even if server supports posix ones - switches on
> Windows locking mechanism. Share flags is another locking mehanism
> provided by Windows semantic that can be used by NT_CREATE_ANDX
> command. This patch combines all Windows locking mechanism in one
> mount option by using NT_CREATE_ANDX to open files if forcemand is on.
> Signed-off-by: Pavel Shilovsky
>
> fs/cifs/dir.c  | 1 +
>  fs/cifs/file.c | 6 ++++--
>  2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
> index d4331de..8587021 100644
> --- a/fs/cifs/dir.c
> +++ b/fs/cifs/dir.c
> @@ -217,6 +217,7 @@ cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned int xid,
>    }
>
> if (tcon->unix_ext && cap_unix(tcon->ses) && !tcon->broken_posix_open &&
> -
>    ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0) &&
>  (CIFS_UNIX_POSIX_PATH_OPS_CAP &
> le64_to_cpu(tcon->fsUnixInfo.Capability))) {
> rc = cifs_posix_open(full_path, &newinode, inode->i_sb, mode,
>
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index 9394b2b..19038a4 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -455,8 +455,9 @@ int cifs_open(struct inode *inode, struct file *file)
>    else
>    	oplock = 0;
> - if (!tcon->broken_posix_open && tcon->unix_ext &&
> -
>    cap_unix(tcon->ses) && (CIFS_UNIX_POSIX_PATH_OPS_CAP &
> - if (!tcon->broken_posix_open && tcon->unix_ext && cap_unix(tcon->ses)
> -
>    && ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0) &&
> -
>    (CIFS_UNIX_POSIX_PATH_OPS_CAP &
> 	le64_to_cpu(tcon->fsUnixInfo.Capability))) {
> /* can not refresh inode info since size could be stale */
>   rc = cifs_posix_open(full_path, &inode, inode->i_sb,
>
> @@ -624,6 +625,7 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
>    	oplock = 0;
>
> if (tcon->unix_ext && cap_unix(tcon->ses) &&
> -
>    ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0) &&
>  (CIFS_UNIX_POSIX_PATH_OPS_CAP &
> 	le64_to_cpu(tcon->fsUnixInfo.Capability))) {
> /*

I'm trying to understand why "forcemand" would matter here. Wouldn't
you just want to switch to using NT_CREATE_ANDX if O_DENY* is set
instead? What happens if I didn't mount with forcemand and then try to
use O_DENY*?