Re: [PATCH] cifs: drop the lease for cached directories on rmdir or rename

[Tom Talpey <tom@talpey.com>]

On 10/18/2022 3:39 AM, Ronnie Sahlberg wrote:
> When we delete or rename a directory we must also drop any cached lease we have
> on the directory.

Just curious, why drop the lease on rename? I guess this is related
to setting ReplaceIfExists, but that would apply to a lease on the
existing (replaced) directory, which would then become deleted?

I'm probably undercaffeinated, if not.

Tom.

> Fixes: a350d6e73f5e ("cifs: enable caching of directories for which a lease
> is held")
> Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
> ---
>   fs/cifs/cached_dir.c | 21 +++++++++++++++++++++
>   fs/cifs/cached_dir.h |  4 ++++
>   fs/cifs/smb2inode.c  |  2 ++
>   3 files changed, 27 insertions(+)
> 
> diff --git a/fs/cifs/cached_dir.c b/fs/cifs/cached_dir.c
> index ffc924296e59..6e689c4c8d1b 100644
> --- a/fs/cifs/cached_dir.c
> +++ b/fs/cifs/cached_dir.c
> @@ -340,6 +340,27 @@ smb2_close_cached_fid(struct kref *ref)
>   	free_cached_dir(cfid);
>   }
>   
> +void drop_cached_dir_by_name(const unsigned int xid, struct cifs_tcon *tcon,
> +			     const char *name, struct cifs_sb_info *cifs_sb)
> +{
> +	struct cached_fid *cfid = NULL;
> +	int rc;
> +
> +	rc = open_cached_dir(xid, tcon, name, cifs_sb, true, &cfid);
> +	if (rc) {
> +		cifs_dbg(FYI, "no cached dir found for rmdir(%s)\n", name);
> +		return;
> +	}
> +	spin_lock(&cfid->cfids->cfid_list_lock);
> +	if (cfid->has_lease) {
> +		cfid->has_lease = false;
> +		kref_put(&cfid->refcount, smb2_close_cached_fid);
> +	}
> +	spin_unlock(&cfid->cfids->cfid_list_lock);
> +	close_cached_dir(cfid);
> +}
> +
> +
>   void close_cached_dir(struct cached_fid *cfid)
>   {
>   	kref_put(&cfid->refcount, smb2_close_cached_fid);
> diff --git a/fs/cifs/cached_dir.h b/fs/cifs/cached_dir.h
> index e536304ca2ce..2f4e764c9ca9 100644
> --- a/fs/cifs/cached_dir.h
> +++ b/fs/cifs/cached_dir.h
> @@ -69,6 +69,10 @@ extern int open_cached_dir_by_dentry(struct cifs_tcon *tcon,
>   				     struct dentry *dentry,
>   				     struct cached_fid **cfid);
>   extern void close_cached_dir(struct cached_fid *cfid);
> +extern void drop_cached_dir_by_name(const unsigned int xid,
> +				    struct cifs_tcon *tcon,
> +				    const char *name,
> +				    struct cifs_sb_info *cifs_sb);
>   extern void close_all_cached_dirs(struct cifs_sb_info *cifs_sb);
>   extern void invalidate_all_cached_dirs(struct cifs_tcon *tcon);
>   extern int cached_dir_lease_break(struct cifs_tcon *tcon, __u8 lease_key[16]);
> diff --git a/fs/cifs/smb2inode.c b/fs/cifs/smb2inode.c
> index a6640e6ea58b..68e08c85fbb8 100644
> --- a/fs/cifs/smb2inode.c
> +++ b/fs/cifs/smb2inode.c
> @@ -655,6 +655,7 @@ int
>   smb2_rmdir(const unsigned int xid, struct cifs_tcon *tcon, const char *name,
>   	   struct cifs_sb_info *cifs_sb)
>   {
> +	drop_cached_dir_by_name(xid, tcon, name, cifs_sb);
>   	return smb2_compound_op(xid, tcon, cifs_sb, name, DELETE, FILE_OPEN,
>   				CREATE_NOT_FILE, ACL_NO_MODE,
>   				NULL, SMB2_OP_RMDIR, NULL, NULL, NULL);
> @@ -698,6 +699,7 @@ smb2_rename_path(const unsigned int xid, struct cifs_tcon *tcon,
>   {
>   	struct cifsFileInfo *cfile;
>   
> +	drop_cached_dir_by_name(xid, tcon, from_name, cifs_sb);
>   	cifs_get_writable_path(tcon, from_name, FIND_WR_WITH_DELETE, &cfile);
>   
>   	return smb2_set_path_attr(xid, tcon, from_name, to_name,