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smb: client: relax session and tcon reconnect attempts

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When the client re-establishes connection to the server, it will queue
a worker thread that will attempt to reconnect sessions and tcons on
every two seconds, which is kinda overkill as it is a very common
scenario when having expired passwords or KRB5 TGT tickets, or deleted
shares.

Use an exponential backoff strategy to handle session/tcon reconnect
attempts in the worker thread to prevent the client from overloading
the system when it is very unlikely to re-establish any session/tcon
soon while client is idle.

Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Cc: Pierguido Lambri <plambri@redhat.com>
Cc: linux-cifs@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Paulo Alcantara
2025-12-04 15:06:23 -03:00
committed by Steve French
parent 4ae4dde6f3
commit 855982a52f
3 changed files with 26 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
fs/smb/client/cifsglob.h
View File

@@ -745,6 +745,7 @@ struct TCP_Server_Info {
struct session_key session_key;
unsigned long lstrp; /* when we got last response from this server */
unsigned long neg_start; /* when negotiate started (jiffies) */
unsigned long reconn_delay; /* when resched session and tcon reconnect */
struct cifs_secmech secmech; /* crypto sec mech functs, descriptors */
#define CIFS_NEGFLAVOR_UNENCAP 1 /* wct == 17, but no ext_sec */
#define CIFS_NEGFLAVOR_EXTENDED 2 /* wct == 17, ext_sec bit set */
@@ -2292,4 +2293,24 @@ struct cifs_calc_sig_ctx {
struct shash_desc *shash;
};
#define CIFS_RECONN_DELAY_SECS 30
#define CIFS_MAX_RECONN_DELAY (4 * CIFS_RECONN_DELAY_SECS)
static inline void cifs_queue_server_reconn(struct TCP_Server_Info *server)
{
if (!delayed_work_pending(&server->reconnect)) {
WRITE_ONCE(server->reconn_delay, 0);
mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
}
}
static inline void cifs_requeue_server_reconn(struct TCP_Server_Info *server)
{
unsigned long delay = READ_ONCE(server->reconn_delay);
delay = umin(delay + CIFS_RECONN_DELAY_SECS, CIFS_MAX_RECONN_DELAY);
WRITE_ONCE(server->reconn_delay, delay);
queue_delayed_work(cifsiod_wq, &server->reconnect, delay * HZ);
}
#endif /* _CIFS_GLOB_H */

4
fs/smb/client/connect.c
View File

@@ -425,7 +425,7 @@ static int __cifs_reconnect(struct TCP_Server_Info *server,
spin_unlock(&server->srv_lock);
cifs_swn_reset_server_dstaddr(server);
cifs_server_unlock(server);
mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
cifs_queue_server_reconn(server);
}
} while (server->tcpStatus == CifsNeedReconnect);
@@ -564,7 +564,7 @@ static int reconnect_dfs_server(struct TCP_Server_Info *server)
spin_unlock(&server->srv_lock);
cifs_swn_reset_server_dstaddr(server);
cifs_server_unlock(server);
mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
cifs_queue_server_reconn(server);
} while (server->tcpStatus == CifsNeedReconnect);
dfs_cache_noreq_update_tgthint(ref_path, target_hint);

6
fs/smb/client/smb2pdu.c
View File

@@ -497,7 +497,7 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon,
spin_unlock(&ses->ses_lock);
if (smb2_command != SMB2_INTERNAL_CMD)
mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
cifs_queue_server_reconn(server);
atomic_inc(&tconInfoReconnectCount);
out:
@@ -4316,7 +4316,7 @@ void smb2_reconnect_server(struct work_struct *work)
done:
cifs_dbg(FYI, "Reconnecting tcons and channels finished\n");
if (resched)
queue_delayed_work(cifsiod_wq, &server->reconnect, 2 * HZ);
cifs_requeue_server_reconn(server);
mutex_unlock(&pserver->reconnect_mutex);
/* now we can safely release srv struct */
@@ -4340,7 +4340,7 @@ SMB2_echo(struct TCP_Server_Info *server)
server->ops->need_neg(server)) {
spin_unlock(&server->srv_lock);
/* No need to send echo on newly established connections */
mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
cifs_queue_server_reconn(server);
return rc;
}
spin_unlock(&server->srv_lock);