linux-kernel - Re: [PATCH v3 09/13] filelock: lift the ban on directory leases in generic

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Message-ID: <g7r2bffekbosexqbatj5mb7ljc5rn5rw3dwfehipsxdb6hewyp@heriwuhgh3zo>
Date: Wed, 22 Oct 2025 11:03:19 +0200
From: Jan Kara <jack@...e.cz>
To: Jeff Layton <jlayton@...nel.org>
Cc: Miklos Szeredi <miklos@...redi.hu>, 
	Alexander Viro <viro@...iv.linux.org.uk>, Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>, 
	Chuck Lever <chuck.lever@...cle.com>, Alexander Aring <alex.aring@...il.com>, 
	Trond Myklebust <trondmy@...nel.org>, Anna Schumaker <anna@...nel.org>, 
	Steve French <sfrench@...ba.org>, Paulo Alcantara <pc@...guebit.org>, 
	Ronnie Sahlberg <ronniesahlberg@...il.com>, Shyam Prasad N <sprasad@...rosoft.com>, 
	Tom Talpey <tom@...pey.com>, Bharath SM <bharathsm@...rosoft.com>, 
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>, "Rafael J. Wysocki" <rafael@...nel.org>, 
	Danilo Krummrich <dakr@...nel.org>, David Howells <dhowells@...hat.com>, 
	Tyler Hicks <code@...icks.com>, NeilBrown <neil@...wn.name>, 
	Olga Kornievskaia <okorniev@...hat.com>, Dai Ngo <Dai.Ngo@...cle.com>, 
	Amir Goldstein <amir73il@...il.com>, Namjae Jeon <linkinjeon@...nel.org>, 
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	"David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, Simon Horman <horms@...nel.org>, 
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org, linux-nfs@...r.kernel.org, 
	linux-cifs@...r.kernel.org, samba-technical@...ts.samba.org, netfs@...ts.linux.dev, 
	ecryptfs@...r.kernel.org, linux-unionfs@...r.kernel.org, linux-xfs@...r.kernel.org, 
	netdev@...r.kernel.org
Subject: Re: [PATCH v3 09/13] filelock: lift the ban on directory leases in
 generic_setlease

On Tue 21-10-25 11:25:44, Jeff Layton wrote:
> With the addition of the try_break_lease calls in directory changing
> operations, allow generic_setlease to hand them out. Write leases on
> directories are never allowed however, so continue to reject them.
> 
> For now, there is no API for requesting delegations from userland, so
> ensure that userland is prevented from acquiring a lease on a directory.
> 
> Reviewed-by: NeilBrown <neil@...wn.name>
> Signed-off-by: Jeff Layton <jlayton@...nel.org>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@...e.cz>

								Honza

> ---
>  fs/locks.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/locks.c b/fs/locks.c
> index 0b16921fb52e602ea2e0c3de39d9d772af98ba7d..b47552106769ec5a189babfe12518e34aa59c759 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -1929,14 +1929,19 @@ static int generic_delete_lease(struct file *filp, void *owner)
>  int generic_setlease(struct file *filp, int arg, struct file_lease **flp,
>  			void **priv)
>  {
> -	if (!S_ISREG(file_inode(filp)->i_mode))
> +	struct inode *inode = file_inode(filp);
> +
> +	if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
>  		return -EINVAL;
>  
>  	switch (arg) {
>  	case F_UNLCK:
>  		return generic_delete_lease(filp, *priv);
> -	case F_RDLCK:
>  	case F_WRLCK:
> +		if (S_ISDIR(inode->i_mode))
> +			return -EINVAL;
> +		fallthrough;
> +	case F_RDLCK:
>  		if (!(*flp)->fl_lmops->lm_break) {
>  			WARN_ON_ONCE(1);
>  			return -ENOLCK;
> @@ -2065,6 +2070,9 @@ static int do_fcntl_add_lease(unsigned int fd, struct file *filp, int arg)
>   */
>  int fcntl_setlease(unsigned int fd, struct file *filp, int arg)
>  {
> +	if (S_ISDIR(file_inode(filp)->i_mode))
> +		return -EINVAL;
> +
>  	if (arg == F_UNLCK)
>  		return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp);
>  	return do_fcntl_add_lease(fd, filp, arg);
> 
> -- 
> 2.51.0
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR