staging: lustre: llite: Add client mount opt to ignore suppress_pings

When Lustre servers enable 'suppress_pings', all clients will stop
pinging. However, some clients may not have external mechanism
to notify Lustre servers for node death and therefore need to
preserve the Lustre ping.

This patch provides a mount option 'always_ping' so that the
client will not stop pinging even if the server has enabled
'suppress_pings'.
Signed-off-by: Wally Wang <wang@cray.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6391
Reviewed-on: http://review.whamcloud.com/14127Reviewed-by: Li Wei <wei.g.li@intel.com>
Reviewed-by: Chris Horn <hornc@cray.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/llite/llite_internal.h

@@ -391,6 +391,8 @@ enum stats_track_type {
 #define LL_SBI_USER_FID2PATH  0x40000 /* allow fid2path by unprivileged users */
 #define LL_SBI_XATTR_CACHE    0x80000 /* support for xattr cache */
 #define LL_SBI_NOROOTSQUASH	0x100000 /* do not apply root squash */
+#define LL_SBI_ALWAYS_PING	0x200000 /* always ping even if server
+					  * suppress_pings */
 
 #define LL_SBI_FLAGS {	\
 	"nolck",	\
@@ -414,6 +416,7 @@ enum stats_track_type {
 	"user_fid2path",\
 	"xattr_cache",	\
 	"norootsquash",	\
+	"always_ping",	\
 }
 
 /*

drivers/staging/lustre/lustre/llite/llite_lib.c

@@ -224,6 +224,10 @@ static int client_common_fill_super(struct super_block *sb, char *md, char *dt,
 	/* real client */
 	data->ocd_connect_flags |= OBD_CONNECT_REAL;
 
+	/* always ping even if server suppress_pings */
+	if (sbi->ll_flags & LL_SBI_ALWAYS_PING)
+		data->ocd_connect_flags &= ~OBD_CONNECT_PINGLESS;
+
 	data->ocd_brw_size = MD_MAX_BRW_SIZE;
 
 	err = obd_connect(NULL, &sbi->ll_md_exp, obd, &sbi->ll_sb_uuid,
@@ -373,6 +377,10 @@ static int client_common_fill_super(struct super_block *sb, char *md, char *dt,
 
 	data->ocd_connect_flags |= OBD_CONNECT_LRU_RESIZE;
 
+	/* always ping even if server suppress_pings */
+	if (sbi->ll_flags & LL_SBI_ALWAYS_PING)
+		data->ocd_connect_flags &= ~OBD_CONNECT_PINGLESS;
+
 	CDEBUG(D_RPCTRACE, "ocd_connect_flags: %#llx ocd_version: %d ocd_grant: %d\n",
 	       data->ocd_connect_flags,
 	       data->ocd_version, data->ocd_grant);
@@ -788,6 +796,11 @@ static int ll_options(char *options, int *flags)
 			*flags &= ~tmp;
 			goto next;
 		}
+		tmp = ll_set_opt("always_ping", s1, LL_SBI_ALWAYS_PING);
+		if (tmp) {
+			*flags |= tmp;
+			goto next;
+		}
 		LCONSOLE_ERROR_MSG(0x152, "Unknown option '%s', won't mount.\n",
 				   s1);
 		return -EINVAL;
@@ -2361,6 +2374,9 @@ int ll_show_options(struct seq_file *seq, struct dentry *dentry)
 	if (sbi->ll_flags & LL_SBI_USER_FID2PATH)
 		seq_puts(seq, ",user_fid2path");
 
+	if (sbi->ll_flags & LL_SBI_ALWAYS_PING)
+		seq_puts(seq, ",always_ping");
+
 	return 0;
 }