Re: [PATCH v4 3/7] CIFS: Add O_DENY* open flags support

[Jeff Layton]

On Fri,  5 Apr 2013 20:57:51 +0400
Pavel Shilovsky <piastry@xxxxxxxxxxx> wrote:

> Construct share_access value from O_DENY* flags and send it to
> the server.
> 
> Signed-off-by: Pavel Shilovsky <piastry@xxxxxxxxxxx>
> ---
>  fs/cifs/cifsglob.h | 16 +++++++++++++++-
>  fs/cifs/dir.c      |  3 +++
>  fs/cifs/file.c     |  4 ++++
>  fs/locks.c         |  8 ++++++++
>  4 files changed, 30 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index cd4bbf3..7e876b9 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -465,7 +465,7 @@ struct smb_vol {
>  			 CIFS_MOUNT_CIFS_BACKUPUID | CIFS_MOUNT_CIFS_BACKUPGID)
>  
>  #define CIFS_MS_MASK (MS_RDONLY | MS_MANDLOCK | MS_NOEXEC | MS_NOSUID | \
> -		      MS_NODEV | MS_SYNCHRONOUS)
> +		      MS_NODEV | MS_SYNCHRONOUS | MS_SHARELOCK)
>  
>  struct cifs_mnt_data {
>  	struct cifs_sb_info *cifs_sb;
> @@ -947,6 +947,20 @@ struct cifsFileInfo {
>  	struct work_struct oplock_break; /* work for oplock breaks */
>  };
>  
> +static inline int
> +cifs_get_share_flags(unsigned int flags)
> +{
> +	int share_access = 0;
> +
> +	if (!(flags & O_DENYREAD))
> +		share_access |= FILE_SHARE_READ;
> +	if (!(flags & O_DENYWRITE))
> +		share_access |= FILE_SHARE_WRITE;
> +	if (!(flags & O_DENYDELETE))
> +		share_access |= FILE_SHARE_DELETE;
> +	return share_access;
> +}
> +
>  struct cifs_io_parms {
>  	__u16 netfid;
>  #ifdef CONFIG_CIFS_SMB2
> diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
> index 267b608..d4331de 100644
> --- a/fs/cifs/dir.c
> +++ b/fs/cifs/dir.c
> @@ -294,6 +294,9 @@ cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned int xid,
>  	else
>  		cFYI(1, "Create flag not set in create function");
>  
> +	if (IS_SHARELOCK(inode))
> +		share_access = cifs_get_share_flags(oflags);
> +
>  	/*
>  	 * BB add processing to set equivalent of mode - e.g. via CreateX with
>  	 * ACLs
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index 0d524a7..9394b2b 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -210,6 +210,8 @@ cifs_nt_open(char *full_path, struct inode *inode, struct cifs_sb_info *cifs_sb,
>   *********************************************************************/
>  
>  	disposition = cifs_get_disposition(f_flags);
> +	if (IS_SHARELOCK(inode))
> +		share_access = cifs_get_share_flags(f_flags);
>  
>  	/* BB pass O_SYNC flag through on file attributes .. BB */
>  
> @@ -645,6 +647,8 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
>  	}
>  
>  	desired_access = cifs_convert_flags(cfile->f_flags);
> +	if (IS_SHARELOCK(inode))
> +		share_access = cifs_get_share_flags(cfile->f_flags);
>  
>  	if (backup_cred(cifs_sb))
>  		create_options |= CREATE_OPEN_BACKUP_INTENT;
> diff --git a/fs/locks.c b/fs/locks.c
> index 1eccc75..2184ddd 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -846,10 +846,18 @@ deny_lock_file(struct file *filp)
>  {
>  	struct file_lock *lock;
>  	int error = 0;
> +	const char *fsname = filp->f_path.dentry->d_inode->i_sb->s_type->name;
>  
>  	if (!IS_SHARELOCK(filp->f_path.dentry->d_inode))
>  		return error;
>  
> +	/*
> +	 * Don't set a lock on CIFS file systems because they can process it
> +	 * themselves.
> +	 */
> +	if (!strncmp(fsname, "cifs", 4))
> +		return error;
> +

NAK....

This is really nasty. Instead of doing this, you should instead create
a new file_system_type->fs_flags value. Then, set that flag for cifs
and nfs4, and test it here.


>  	error = flock_make_lock(filp, &lock, deny_flags_to_cmd(filp->f_flags));
>  	if (error)
>  		return error;


-- 
Jeff Layton <jlayton@xxxxxxxxxx>
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