2023-06-23 21:49:06

by Bhatnagar, Rishabh

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

From: "Paulo Alcantara (SUSE)" <[email protected]>

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) <[email protected]>
Reviewed-by: Aurelien Aptel <[email protected]>
Signed-off-by: Steve French <[email protected]>
Signed-off-by: Rishabh Bhatnagar <[email protected]>
---
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);
+
+ 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

2023-06-26 06:14:28

by Shyam Prasad N

Subject: Re: [PATCH 5.4 3/5] cifs: Introduce helpers for finding TCP connection

On Sat, Jun 24, 2023 at 3:14 AM Rishabh Bhatnagar <[email protected]> wrote:
>
> From: "Paulo Alcantara (SUSE)" <[email protected]>
>
> 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) <[email protected]>
> Reviewed-by: Aurelien Aptel <[email protected]>
> Signed-off-by: Steve French <[email protected]>
> Signed-off-by: Rishabh Bhatnagar <[email protected]>
> ---
> 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
>


--
Regards,
Shyam

2023-06-26 06:42:02

by Shyam Prasad N

Subject: Re: [PATCH 5.4 3/5] cifs: Introduce helpers for finding TCP connection

On Mon, Jun 26, 2023 at 11:43 AM Greg KH <[email protected]> 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 <[email protected]> wrote:
> > >
> > > From: "Paulo Alcantara (SUSE)" <[email protected]>
> > >
> > > 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) <[email protected]>
> > > Reviewed-by: Aurelien Aptel <[email protected]>
> > > Signed-off-by: Steve French <[email protected]>
> > > Signed-off-by: Rishabh Bhatnagar <[email protected]>
> > > ---
> > > 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.

--
Regards,
Shyam

2023-06-26 06:52:21

by Greg Kroah-Hartman

Subject: Re: [PATCH 5.4 3/5] cifs: Introduce helpers for finding TCP connection

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 <[email protected]> wrote:
> >
> > From: "Paulo Alcantara (SUSE)" <[email protected]>
> >
> > 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) <[email protected]>
> > Reviewed-by: Aurelien Aptel <[email protected]>
> > Signed-off-by: Steve French <[email protected]>
> > Signed-off-by: Rishabh Bhatnagar <[email protected]>
> > ---
> > 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