diff mbox series

[5.4,3/5] cifs: Introduce helpers for finding TCP connection

Message ID 20230623213406.5596-4-risbhat@amazon.com (mailing list archive)
State New, archived
Headers show
Series CIFS DFS fixes for 5.4 | expand

Commit Message

Rishabh Bhatnagar June 23, 2023, 9:34 p.m. UTC 
From: "Paulo Alcantara (SUSE)" <pc@cjr.nz>

commit 345c1a4a9e09dc5842b7bbb6728a77910db69c52 upstream.

Add helpers for finding TCP connections that are good candidates for
being used by DFS refresh worker.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Rishabh Bhatnagar <risbhat@amazon.com>
---
 fs/cifs/dfs_cache.c | 44 +++++++++++++++++++++++++++++++-------------
 1 file changed, 31 insertions(+), 13 deletions(-)

Comments

Shyam Prasad N June 26, 2023, 6:04 a.m. UTC | #1 
On Sat, Jun 24, 2023 at 3:14 AM Rishabh Bhatnagar <risbhat@amazon.com> wrote:
>
> From: "Paulo Alcantara (SUSE)" <pc@cjr.nz>
>
> commit 345c1a4a9e09dc5842b7bbb6728a77910db69c52 upstream.
>
> Add helpers for finding TCP connections that are good candidates for
> being used by DFS refresh worker.
>
> Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
> Reviewed-by: Aurelien Aptel <aaptel@suse.com>
> Signed-off-by: Steve French <stfrench@microsoft.com>
> Signed-off-by: Rishabh Bhatnagar <risbhat@amazon.com>
> ---
>  fs/cifs/dfs_cache.c | 44 +++++++++++++++++++++++++++++++-------------
>  1 file changed, 31 insertions(+), 13 deletions(-)
>
> diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c
> index 3ca65051b55c..31b3dc09e109 100644
> --- a/fs/cifs/dfs_cache.c
> +++ b/fs/cifs/dfs_cache.c
> @@ -1305,6 +1305,30 @@ static char *get_dfs_root(const char *path)
>         return npath;
>  }
>
> +static inline void put_tcp_server(struct TCP_Server_Info *server)
> +{
> +       cifs_put_tcp_session(server, 0);
> +}
> +
> +static struct TCP_Server_Info *get_tcp_server(struct smb_vol *vol)
> +{
> +       struct TCP_Server_Info *server;
> +
> +       server = cifs_find_tcp_session(vol);
> +       if (IS_ERR_OR_NULL(server))
> +               return NULL;
> +
> +       spin_lock(&GlobalMid_Lock);
> +       if (server->tcpStatus != CifsGood) {
> +               spin_unlock(&GlobalMid_Lock);
> +               put_tcp_server(server);
> +               return NULL;
> +       }
> +       spin_unlock(&GlobalMid_Lock);

We've moved away from using GlobalMid_Lock for anything other than MIDs.
Please use server->srv_lock instead.

> +
> +       return server;
> +}
> +
>  /* Find root SMB session out of a DFS link path */
>  static struct cifs_ses *find_root_ses(struct vol_info *vi,
>                                       struct cifs_tcon *tcon,
> @@ -1347,13 +1371,8 @@ static struct cifs_ses *find_root_ses(struct vol_info *vi,
>                 goto out;
>         }
>
> -       server = cifs_find_tcp_session(&vol);
> -       if (IS_ERR_OR_NULL(server)) {
> -               ses = ERR_PTR(-EHOSTDOWN);
> -               goto out;
> -       }
> -       if (server->tcpStatus != CifsGood) {
> -               cifs_put_tcp_session(server, 0);
> +       server = get_tcp_server(&vol);
> +       if (!server) {
>                 ses = ERR_PTR(-EHOSTDOWN);
>                 goto out;
>         }
> @@ -1451,19 +1470,18 @@ static void refresh_cache_worker(struct work_struct *work)
>         mutex_lock(&vol_lock);
>
>         list_for_each_entry(vi, &vol_list, list) {
> -               server = cifs_find_tcp_session(&vi->smb_vol);
> -               if (IS_ERR_OR_NULL(server))
> +               server = get_tcp_server(&vi->smb_vol);
> +               if (!server)
>                         continue;
> -               if (server->tcpStatus != CifsGood)
> -                       goto next;
> +
>                 get_tcons(server, &list);
>                 list_for_each_entry_safe(tcon, ntcon, &list, ulist) {
>                         refresh_tcon(vi, tcon);
>                         list_del_init(&tcon->ulist);
>                         cifs_put_tcon(tcon);
>                 }
> -next:
> -               cifs_put_tcp_session(server, 0);
> +
> +               put_tcp_server(server);
>         }
>         queue_delayed_work(dfscache_wq, &refresh_task, cache_ttl * HZ);
>         mutex_unlock(&vol_lock);
> --
> 2.40.1
>
Greg Kroah-Hartman June 26, 2023, 6:13 a.m. UTC | #2 
On Mon, Jun 26, 2023 at 11:34:44AM +0530, Shyam Prasad N wrote:
> On Sat, Jun 24, 2023 at 3:14 AM Rishabh Bhatnagar <risbhat@amazon.com> wrote:
> >
> > From: "Paulo Alcantara (SUSE)" <pc@cjr.nz>
> >
> > commit 345c1a4a9e09dc5842b7bbb6728a77910db69c52 upstream.
> >
> > Add helpers for finding TCP connections that are good candidates for
> > being used by DFS refresh worker.
> >
> > Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
> > Reviewed-by: Aurelien Aptel <aaptel@suse.com>
> > Signed-off-by: Steve French <stfrench@microsoft.com>
> > Signed-off-by: Rishabh Bhatnagar <risbhat@amazon.com>
> > ---
> >  fs/cifs/dfs_cache.c | 44 +++++++++++++++++++++++++++++++-------------
> >  1 file changed, 31 insertions(+), 13 deletions(-)
> >
> > diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c
> > index 3ca65051b55c..31b3dc09e109 100644
> > --- a/fs/cifs/dfs_cache.c
> > +++ b/fs/cifs/dfs_cache.c
> > @@ -1305,6 +1305,30 @@ static char *get_dfs_root(const char *path)
> >         return npath;
> >  }
> >
> > +static inline void put_tcp_server(struct TCP_Server_Info *server)
> > +{
> > +       cifs_put_tcp_session(server, 0);
> > +}
> > +
> > +static struct TCP_Server_Info *get_tcp_server(struct smb_vol *vol)
> > +{
> > +       struct TCP_Server_Info *server;
> > +
> > +       server = cifs_find_tcp_session(vol);
> > +       if (IS_ERR_OR_NULL(server))
> > +               return NULL;
> > +
> > +       spin_lock(&GlobalMid_Lock);
> > +       if (server->tcpStatus != CifsGood) {
> > +               spin_unlock(&GlobalMid_Lock);
> > +               put_tcp_server(server);
> > +               return NULL;
> > +       }
> > +       spin_unlock(&GlobalMid_Lock);
> 
> We've moved away from using GlobalMid_Lock for anything other than MIDs.
> Please use server->srv_lock instead.

This is just a backport of a commit that showed up in the 5.6 release.
It's not new development.

thanks,

greg k-h
Shyam Prasad N June 26, 2023, 6:30 a.m. UTC | #3 
On Mon, Jun 26, 2023 at 11:43 AM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Mon, Jun 26, 2023 at 11:34:44AM +0530, Shyam Prasad N wrote:
> > On Sat, Jun 24, 2023 at 3:14 AM Rishabh Bhatnagar <risbhat@amazon.com> wrote:
> > >
> > > From: "Paulo Alcantara (SUSE)" <pc@cjr.nz>
> > >
> > > commit 345c1a4a9e09dc5842b7bbb6728a77910db69c52 upstream.
> > >
> > > Add helpers for finding TCP connections that are good candidates for
> > > being used by DFS refresh worker.
> > >
> > > Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
> > > Reviewed-by: Aurelien Aptel <aaptel@suse.com>
> > > Signed-off-by: Steve French <stfrench@microsoft.com>
> > > Signed-off-by: Rishabh Bhatnagar <risbhat@amazon.com>
> > > ---
> > >  fs/cifs/dfs_cache.c | 44 +++++++++++++++++++++++++++++++-------------
> > >  1 file changed, 31 insertions(+), 13 deletions(-)
> > >
> > > diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c
> > > index 3ca65051b55c..31b3dc09e109 100644
> > > --- a/fs/cifs/dfs_cache.c
> > > +++ b/fs/cifs/dfs_cache.c
> > > @@ -1305,6 +1305,30 @@ static char *get_dfs_root(const char *path)
> > >         return npath;
> > >  }
> > >
> > > +static inline void put_tcp_server(struct TCP_Server_Info *server)
> > > +{
> > > +       cifs_put_tcp_session(server, 0);
> > > +}
> > > +
> > > +static struct TCP_Server_Info *get_tcp_server(struct smb_vol *vol)
> > > +{
> > > +       struct TCP_Server_Info *server;
> > > +
> > > +       server = cifs_find_tcp_session(vol);
> > > +       if (IS_ERR_OR_NULL(server))
> > > +               return NULL;
> > > +
> > > +       spin_lock(&GlobalMid_Lock);
> > > +       if (server->tcpStatus != CifsGood) {
> > > +               spin_unlock(&GlobalMid_Lock);
> > > +               put_tcp_server(server);
> > > +               return NULL;
> > > +       }
> > > +       spin_unlock(&GlobalMid_Lock);
> >
> > We've moved away from using GlobalMid_Lock for anything other than MIDs.
> > Please use server->srv_lock instead.
>
> This is just a backport of a commit that showed up in the 5.6 release.
> It's not new development.
>
> thanks,
>
> greg k-h

Ah. I get it now.
Sorry for the confusion.
diff mbox series

Patch

diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c
index 3ca65051b55c..31b3dc09e109 100644
--- a/fs/cifs/dfs_cache.c
+++ b/fs/cifs/dfs_cache.c
@@ -1305,6 +1305,30 @@  static char *get_dfs_root(const char *path)
 	return npath;
 }
 
+static inline void put_tcp_server(struct TCP_Server_Info *server)
+{
+	cifs_put_tcp_session(server, 0);
+}
+
+static struct TCP_Server_Info *get_tcp_server(struct smb_vol *vol)
+{
+	struct TCP_Server_Info *server;
+
+	server = cifs_find_tcp_session(vol);
+	if (IS_ERR_OR_NULL(server))
+		return NULL;
+
+	spin_lock(&GlobalMid_Lock);
+	if (server->tcpStatus != CifsGood) {
+		spin_unlock(&GlobalMid_Lock);
+		put_tcp_server(server);
+		return NULL;
+	}
+	spin_unlock(&GlobalMid_Lock);
+
+	return server;
+}
+
 /* Find root SMB session out of a DFS link path */
 static struct cifs_ses *find_root_ses(struct vol_info *vi,
 				      struct cifs_tcon *tcon,
@@ -1347,13 +1371,8 @@  static struct cifs_ses *find_root_ses(struct vol_info *vi,
 		goto out;
 	}
 
-	server = cifs_find_tcp_session(&vol);
-	if (IS_ERR_OR_NULL(server)) {
-		ses = ERR_PTR(-EHOSTDOWN);
-		goto out;
-	}
-	if (server->tcpStatus != CifsGood) {
-		cifs_put_tcp_session(server, 0);
+	server = get_tcp_server(&vol);
+	if (!server) {
 		ses = ERR_PTR(-EHOSTDOWN);
 		goto out;
 	}
@@ -1451,19 +1470,18 @@  static void refresh_cache_worker(struct work_struct *work)
 	mutex_lock(&vol_lock);
 
 	list_for_each_entry(vi, &vol_list, list) {
-		server = cifs_find_tcp_session(&vi->smb_vol);
-		if (IS_ERR_OR_NULL(server))
+		server = get_tcp_server(&vi->smb_vol);
+		if (!server)
 			continue;
-		if (server->tcpStatus != CifsGood)
-			goto next;
+
 		get_tcons(server, &list);
 		list_for_each_entry_safe(tcon, ntcon, &list, ulist) {
 			refresh_tcon(vi, tcon);
 			list_del_init(&tcon->ulist);
 			cifs_put_tcon(tcon);
 		}
-next:
-		cifs_put_tcp_session(server, 0);
+
+		put_tcp_server(server);
 	}
 	queue_delayed_work(dfscache_wq, &refresh_task, cache_ttl * HZ);
 	mutex_unlock(&vol_lock);