path: root/sys-cluster/lustre/files/0003-LU-3319-procfs-fix-symlink-handling.patch

From ce693d2759e274a114a668e477264d1af8181159 Mon Sep 17 00:00:00 2001
From: James Simmons <uja.ornl@gmail.com>
Date: Fri, 31 Jan 2014 11:37:53 -0500
Subject: [PATCH 03/13] LU-3319 procfs: fix symlink handling

While working on symlink handling for seq files I noticed a
long outstanding bug. Code was developed to link osc obds
to target_obds of the lov layer. The target_obds directory
was never created for the symlinks. This patches enables
this long forgotten feature. Also addressed is the race
condition experinced with server side code ported to
seq_files that used symlinks. To avoid the race the handle
obd_proc_private was moved from struct obd_device to
struct obd_type which now allows earlier registeration that
only happens once.

Change-Id: Ib158ec4444ed7abc0f3c3e820ee4a333631a58d1
Signed-off-by: James Simmons <uja.ornl@gmail.com>
---
 lustre/include/obd.h     |  17 ++++----
 lustre/lmv/lmv_obd.c     |  49 +++++++++--------------
 lustre/lov/lov_obd.c     | 100 +++++++++++++++++++++++++++--------------------
 lustre/obdclass/genops.c |   3 ++
 4 files changed, 87 insertions(+), 82 deletions(-)

diff --git a/lustre/include/obd.h b/lustre/include/obd.h
index c18052b..8fd2ce7 100644
--- a/lustre/include/obd.h
+++ b/lustre/include/obd.h
@@ -183,13 +183,15 @@ struct obd_info {
 };
 
 struct obd_type {
-        cfs_list_t typ_chain;
-        struct obd_ops *typ_dt_ops;
-        struct md_ops *typ_md_ops;
-        cfs_proc_dir_entry_t *typ_procroot;
-        char *typ_name;
-        int  typ_refcnt;
-        struct lu_device_type *typ_lu;
+	struct list_head typ_chain;
+	struct obd_ops *typ_dt_ops;
+	struct md_ops *typ_md_ops;
+	cfs_proc_dir_entry_t *typ_procroot;
+	cfs_proc_dir_entry_t *typ_procsym;
+	__u32 typ_sym_filter;
+	char *typ_name;
+	int  typ_refcnt;
+	struct lu_device_type *typ_lu;
 	spinlock_t obd_type_lock;
 };
 
@@ -825,7 +827,6 @@ struct obd_device {
 
 	struct proc_dir_entry	*obd_proc_entry;
 	struct proc_dir_entry	*obd_proc_exports_entry;
-	void			*obd_proc_private;	/* type private PDEs */
 	struct proc_dir_entry	*obd_svc_procroot;
 	struct lprocfs_stats	*obd_svc_stats;
 	struct lprocfs_seq_vars	*obd_vars;
diff --git a/lustre/lmv/lmv_obd.c b/lustre/lmv/lmv_obd.c
index e0941c9..7e1738e 100644
--- a/lustre/lmv/lmv_obd.c
+++ b/lustre/lmv/lmv_obd.c
@@ -242,9 +242,6 @@ static int lmv_connect(const struct lu_env *env,
                        struct obd_uuid *cluuid, struct obd_connect_data *data,
                        void *localdata)
 {
-#ifdef __KERNEL__
-        struct proc_dir_entry *lmv_proc_dir;
-#endif
         struct lmv_obd        *lmv = &obd->u.lmv;
         struct lustre_handle  conn = { 0 };
         int                    rc = 0;
@@ -277,18 +274,15 @@ static int lmv_connect(const struct lu_env *env,
                 lmv->conn_data = *data;
 
 #ifdef __KERNEL__
-	if (obd->obd_proc_private != NULL) {
-		lmv_proc_dir = obd->obd_proc_private;
-	} else {
-		lmv_proc_dir = lprocfs_seq_register("target_obds",
-						    obd->obd_proc_entry,
-						    NULL, NULL);
-		if (IS_ERR(lmv_proc_dir)) {
+	if (obd->obd_type->typ_procsym == NULL) {
+		obd->obd_type->typ_procsym = lprocfs_seq_register("target_obds",
+							 obd->obd_proc_entry,
+							 NULL, NULL);
+		if (IS_ERR(obd->obd_type->typ_procsym)) {
 			CERROR("could not register /proc/fs/lustre/%s/%s/target_obds.",
 			       obd->obd_type->typ_name, obd->obd_name);
-			lmv_proc_dir = NULL;
+			obd->obd_type->typ_procsym = NULL;
 		}
-		obd->obd_proc_private = lmv_proc_dir;
 	}
 #endif
 
@@ -302,9 +296,9 @@ static int lmv_connect(const struct lu_env *env,
                 rc = lmv_check_connect(obd);
 
 #ifdef __KERNEL__
-	if (rc && lmv_proc_dir) {
-		lprocfs_remove(&lmv_proc_dir);
-		obd->obd_proc_private = NULL;
+	if (rc && obd->obd_type->typ_procsym != NULL) {
+		lprocfs_remove(&obd->obd_type->typ_procsym);
+		obd->obd_type->typ_procsym = NULL;
 	}
 #endif
         RETURN(rc);
@@ -384,9 +378,6 @@ static int lmv_init_ea_size(struct obd_export *exp, int easize,
 
 int lmv_connect_mdc(struct obd_device *obd, struct lmv_tgt_desc *tgt)
 {
-#ifdef __KERNEL__
-        struct proc_dir_entry   *lmv_proc_dir;
-#endif
         struct lmv_obd          *lmv = &obd->u.lmv;
         struct obd_uuid         *cluuid = &lmv->cluuid;
         struct obd_uuid          lmv_mdc_uuid = { "LMV_MDC_UUID" };
@@ -466,14 +457,13 @@ int lmv_connect_mdc(struct obd_device *obd, struct lmv_tgt_desc *tgt)
                 cfs_atomic_read(&obd->obd_refcount));
 
 #ifdef __KERNEL__
-	lmv_proc_dir = obd->obd_proc_private;
-	if (lmv_proc_dir) {
+	if (obd->obd_type->typ_procsym != NULL) {
 		struct proc_dir_entry *mdc_symlink;
 
 		LASSERT(mdc_obd->obd_type != NULL);
 		LASSERT(mdc_obd->obd_type->typ_name != NULL);
 		mdc_symlink = lprocfs_add_symlink(mdc_obd->obd_name,
-						  lmv_proc_dir,
+						  obd->obd_type->typ_procsym,
 						  "../../../%s/%s",
 						  mdc_obd->obd_type->typ_name,
 						  mdc_obd->obd_name);
@@ -482,8 +472,8 @@ int lmv_connect_mdc(struct obd_device *obd, struct lmv_tgt_desc *tgt)
 			       "/proc/fs/lustre/%s/%s/target_obds/%s.",
 			       obd->obd_type->typ_name, obd->obd_name,
 			       mdc_obd->obd_name);
-			lprocfs_remove(&lmv_proc_dir);
-			obd->obd_proc_private = NULL;
+			lprocfs_remove(&obd->obd_type->typ_procsym);
+			obd->obd_type->typ_procsym = NULL;
 		}
 	}
 #endif
@@ -675,9 +665,6 @@ int lmv_check_connect(struct obd_device *obd)
 
 static int lmv_disconnect_mdc(struct obd_device *obd, struct lmv_tgt_desc *tgt)
 {
-#ifdef __KERNEL__
-        struct proc_dir_entry  *lmv_proc_dir;
-#endif
         struct lmv_obd         *lmv = &obd->u.lmv;
         struct obd_device      *mdc_obd;
         int                     rc;
@@ -695,9 +682,9 @@ static int lmv_disconnect_mdc(struct obd_device *obd, struct lmv_tgt_desc *tgt)
         }
 
 #ifdef __KERNEL__
-	lmv_proc_dir = obd->obd_proc_private;
-	if (lmv_proc_dir)
-		lprocfs_remove_proc_entry(mdc_obd->obd_name, lmv_proc_dir);
+	if (obd->obd_type->typ_procsym != NULL)
+		lprocfs_remove_proc_entry(mdc_obd->obd_name,
+					  obd->obd_type->typ_procsym);
 #endif
 	rc = obd_fid_fini(tgt->ltd_exp->exp_obd);
 	if (rc)
@@ -747,8 +734,8 @@ static int lmv_disconnect(struct obd_export *exp)
         }
 
 #ifdef __KERNEL__
-	if (obd->obd_proc_private)
-		lprocfs_remove((struct proc_dir_entry **)&obd->obd_proc_private);
+	if (obd->obd_type->typ_procsym != NULL)
+		lprocfs_remove(&obd->obd_type->typ_procsym);
 	else
 		CERROR("/proc/fs/lustre/%s/%s/target_obds missing\n",
 		       obd->obd_type->typ_name, obd->obd_name);
diff --git a/lustre/lov/lov_obd.c b/lustre/lov/lov_obd.c
index 286cd15..b52a263 100644
--- a/lustre/lov/lov_obd.c
+++ b/lustre/lov/lov_obd.c
@@ -127,19 +127,16 @@ static int lov_notify(struct obd_device *obd, struct obd_device *watched,
 int lov_connect_obd(struct obd_device *obd, __u32 index, int activate,
                     struct obd_connect_data *data)
 {
-        struct lov_obd *lov = &obd->u.lov;
-        struct obd_uuid *tgt_uuid;
-        struct obd_device *tgt_obd;
-        static struct obd_uuid lov_osc_uuid = { "LOV_OSC_UUID" };
-        struct obd_import *imp;
-#ifdef __KERNEL__
-	struct proc_dir_entry *lov_proc_dir;
-#endif
-        int rc;
-        ENTRY;
+	struct lov_obd *lov = &obd->u.lov;
+	struct obd_uuid *tgt_uuid;
+	struct obd_device *tgt_obd;
+	static struct obd_uuid lov_osc_uuid = { "LOV_OSC_UUID" };
+	struct obd_import *imp;
+	int rc;
+	ENTRY;
 
-        if (!lov->lov_tgts[index])
-                RETURN(-EINVAL);
+	if (lov->lov_tgts[index] == NULL)
+		RETURN(-EINVAL);
 
         tgt_uuid = &lov->lov_tgts[index]->ltd_uuid;
         tgt_obd = lov->lov_tgts[index]->ltd_obd;
@@ -195,27 +192,26 @@ int lov_connect_obd(struct obd_device *obd, __u32 index, int activate,
                obd_uuid2str(tgt_uuid), tgt_obd->obd_name, activate ? "":"in");
 
 #ifdef __KERNEL__
-	lov_proc_dir = obd->obd_proc_private;
-        if (lov_proc_dir) {
-                struct obd_device *osc_obd = lov->lov_tgts[index]->ltd_exp->exp_obd;
+	if (obd->obd_type->typ_procsym != NULL) {
+		struct obd_device *osc_obd = lov->lov_tgts[index]->ltd_exp->exp_obd;
 		struct proc_dir_entry *osc_symlink;
 
-                LASSERT(osc_obd != NULL);
-                LASSERT(osc_obd->obd_magic == OBD_DEVICE_MAGIC);
-                LASSERT(osc_obd->obd_type->typ_name != NULL);
-
-                osc_symlink = lprocfs_add_symlink(osc_obd->obd_name,
-                                                  lov_proc_dir,
-                                                  "../../../%s/%s",
-                                                  osc_obd->obd_type->typ_name,
-                                                  osc_obd->obd_name);
-                if (osc_symlink == NULL) {
-                        CERROR("could not register LOV target "
-                                "/proc/fs/lustre/%s/%s/target_obds/%s.",
-                                obd->obd_type->typ_name, obd->obd_name,
-                                osc_obd->obd_name);
-                        lprocfs_remove(&lov_proc_dir);
-			obd->obd_proc_private = NULL;
+		LASSERT(osc_obd != NULL);
+		LASSERT(osc_obd->obd_magic == OBD_DEVICE_MAGIC);
+		LASSERT(osc_obd->obd_type->typ_name != NULL);
+
+		osc_symlink = lprocfs_add_symlink(osc_obd->obd_name,
+						  obd->obd_type->typ_procsym,
+						  "../../../%s/%s",
+						  osc_obd->obd_type->typ_name,
+						  osc_obd->obd_name);
+		if (osc_symlink == NULL) {
+			CERROR("could not register LOV target "
+			       "/proc/fs/lustre/%s/%s/target_obds/%s.",
+			       obd->obd_type->typ_name, obd->obd_name,
+			       osc_obd->obd_name);
+			lprocfs_remove(&obd->obd_type->typ_procsym);
+			obd->obd_type->typ_procsym = NULL;
                 }
         }
 #endif
@@ -250,6 +246,17 @@ static int lov_connect(const struct lu_env *env,
         if (data)
                 lov->lov_ocd = *data;
 
+#ifdef __KERNEL__
+	obd->obd_type->typ_procsym = lprocfs_seq_register("target_obds",
+						 obd->obd_proc_entry,
+						 NULL, NULL);
+	if (IS_ERR(obd->obd_type->typ_procsym)) {
+		CERROR("could not register /proc/fs/lustre/%s/%s/target_obds.",
+		       obd->obd_type->typ_name, obd->obd_name);
+		obd->obd_type->typ_procsym = NULL;
+	}
+#endif
+
         obd_getref(obd);
         for (i = 0; i < lov->desc.ld_tgt_count; i++) {
                 tgt = lov->lov_tgts[i];
@@ -280,7 +287,6 @@ static int lov_connect(const struct lu_env *env,
 
 static int lov_disconnect_obd(struct obd_device *obd, struct lov_tgt_desc *tgt)
 {
-	struct proc_dir_entry *lov_proc_dir;
         struct lov_obd *lov = &obd->u.lov;
         struct obd_device *osc_obd;
         int rc;
@@ -296,18 +302,18 @@ static int lov_disconnect_obd(struct obd_device *obd, struct lov_tgt_desc *tgt)
                 tgt->ltd_exp->exp_obd->obd_inactive = 1;
         }
 
-	lov_proc_dir = obd->obd_proc_private;
-	if (lov_proc_dir)
-		lprocfs_remove_proc_entry(osc_obd->obd_name, lov_proc_dir);
+	if (obd->obd_type->typ_procsym)
+		lprocfs_remove_proc_entry(osc_obd->obd_name,
+					  obd->obd_type->typ_procsym);
 
-        if (osc_obd) {
-                /* Pass it on to our clients.
-                 * XXX This should be an argument to disconnect,
-                 * XXX not a back-door flag on the OBD.  Ah well.
-                 */
-                osc_obd->obd_force = obd->obd_force;
-                osc_obd->obd_fail = obd->obd_fail;
-                osc_obd->obd_no_recov = obd->obd_no_recov;
+	if (osc_obd) {
+		/* Pass it on to our clients.
+		 * XXX This should be an argument to disconnect,
+		 * XXX not a back-door flag on the OBD.  Ah well.
+		 */
+		osc_obd->obd_force = obd->obd_force;
+		osc_obd->obd_fail = obd->obd_fail;
+		osc_obd->obd_no_recov = obd->obd_no_recov;
         }
 
         obd_register_observer(osc_obd, NULL);
@@ -353,6 +359,14 @@ static int lov_disconnect(struct obd_export *exp)
         }
         obd_putref(obd);
 
+#ifdef __KERNEL__
+	if (obd->obd_type->typ_procsym)
+		lprocfs_remove(&obd->obd_type->typ_procsym);
+	else
+		CERROR("/proc/fs/lustre/%s/%s/target_obds missing\n",
+		       obd->obd_type->typ_name, obd->obd_name);
+#endif
+
 out:
         rc = class_disconnect(exp); /* bz 9811 */
         RETURN(rc);
diff --git a/lustre/obdclass/genops.c b/lustre/obdclass/genops.c
index c9d8a4e..b9606bb 100644
--- a/lustre/obdclass/genops.c
+++ b/lustre/obdclass/genops.c
@@ -220,6 +220,7 @@ int class_register_type(struct obd_ops *dt_ops, struct md_ops *md_ops,
 		type->typ_procroot = NULL;
 		GOTO (failed, rc);
 	}
+	type->typ_procsym = NULL;
 #endif
         if (ldt != NULL) {
                 type->typ_lu = ldt;
@@ -242,6 +243,8 @@ int class_register_type(struct obd_ops *dt_ops, struct md_ops *md_ops,
         if (type->typ_dt_ops != NULL)
                 OBD_FREE_PTR(type->typ_dt_ops);
 #ifdef LPROCFS
+	if (type->typ_procsym != NULL)
+		lprocfs_remove(&type->typ_procsym);
 #ifndef HAVE_ONLY_PROCFS_SEQ
 	lprocfs_try_remove_proc_entry(type->typ_name, proc_lustre_root);
 #else
-- 
1.8.5.3