Merge branch 'master' of /pub/scm/linux/kernel/git/torvalds/linux-2.6

1 files changed, 74 insertions, 14 deletions

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 31056abca89d..24b2b1e32fae 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -10,6 +10,7 @@
 #include "dm-hw-handler.h"
 #include "dm-bio-list.h"
 #include "dm-bio-record.h"
+#include "dm-uevent.h"
 
 #include <linux/ctype.h>
 #include <linux/init.h>
@@ -75,6 +76,8 @@ struct multipath {
         unsigned queue_io;              /* Must we queue all I/O? */
         unsigned queue_if_no_path;      /* Queue I/O if last path fails? */
         unsigned saved_queue_if_no_path;/* Saved state during suspension */
+        unsigned pg_init_retries;       /* Number of times to retry pg_init */
+        unsigned pg_init_count;         /* Number of times pg_init called */
 
         struct work_struct process_queued_ios;
         struct bio_list queued_ios;
@@ -225,6 +228,8 @@ static void __switch_pg(struct multipath *m, struct pgpath *pgpath)
                 m->pg_init_required = 0;
                 m->queue_io = 0;
         }
+
+        m->pg_init_count = 0;
 }
 
 static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg)
@@ -424,6 +429,7 @@ static void process_queued_ios(struct work_struct *work)
                 must_queue = 0;
 
         if (m->pg_init_required && !m->pg_init_in_progress) {
+                m->pg_init_count++;
                 m->pg_init_required = 0;
                 m->pg_init_in_progress = 1;
                 init_required = 1;
@@ -689,9 +695,11 @@ static int parse_features(struct arg_set *as, struct multipath *m)
         int r;
         unsigned argc;
         struct dm_target *ti = m->ti;
+        const char *param_name;
 
         static struct param _params[] = {
-                {0, 1, "invalid number of feature args"},
+                {0, 3, "invalid number of feature args"},
+                {1, 50, "pg_init_retries must be between 1 and 50"},
         };
 
         r = read_param(_params, shift(as), &argc, &ti->error);
@@ -701,12 +709,28 @@ static int parse_features(struct arg_set *as, struct multipath *m)
         if (!argc)
                 return 0;
 
-        if (!strnicmp(shift(as), MESG_STR("queue_if_no_path")))
-                return queue_if_no_path(m, 1, 0);
-        else {
+        do {
+                param_name = shift(as);
+                argc--;
+
+                if (!strnicmp(param_name, MESG_STR("queue_if_no_path"))) {
+                        r = queue_if_no_path(m, 1, 0);
+                        continue;
+                }
+
+                if (!strnicmp(param_name, MESG_STR("pg_init_retries")) &&
+                    (argc >= 1)) {
+                        r = read_param(_params + 1, shift(as),
+                                       &m->pg_init_retries, &ti->error);
+                        argc--;
+                        continue;
+                }
+
                 ti->error = "Unrecognised multipath feature request";
-                return -EINVAL;
-        }
+                r = -EINVAL;
+        } while (argc && !r);
+
+        return r;
 }
 
 static int multipath_ctr(struct dm_target *ti, unsigned int argc,
@@ -834,6 +858,9 @@ static int fail_path(struct pgpath *pgpath)
         if (pgpath == m->current_pgpath)
                 m->current_pgpath = NULL;
 
+        dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti,
+                      pgpath->path.dev->name, m->nr_valid_paths);
+
         queue_work(kmultipathd, &m->trigger_event);
 
 out:
@@ -873,6 +900,9 @@ static int reinstate_path(struct pgpath *pgpath)
         if (!m->nr_valid_paths++ && m->queue_size)
                 queue_work(kmultipathd, &m->process_queued_ios);
 
+        dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti,
+                      pgpath->path.dev->name, m->nr_valid_paths);
+
         queue_work(kmultipathd, &m->trigger_event);
 
 out:
@@ -976,6 +1006,26 @@ static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed)
 }
 
 /*
+ * Should we retry pg_init immediately?
+ */
+static int pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath)
+{
+        unsigned long flags;
+        int limit_reached = 0;
+
+        spin_lock_irqsave(&m->lock, flags);
+
+        if (m->pg_init_count <= m->pg_init_retries)
+                m->pg_init_required = 1;
+        else
+                limit_reached = 1;
+
+        spin_unlock_irqrestore(&m->lock, flags);
+
+        return limit_reached;
+}
+
+/*
  * pg_init must call this when it has completed its initialisation
  */
 void dm_pg_init_complete(struct dm_path *path, unsigned err_flags)
@@ -985,8 +1035,14 @@ void dm_pg_init_complete(struct dm_path *path, unsigned err_flags)
         struct multipath *m = pg->m;
         unsigned long flags;
 
-        /* We insist on failing the path if the PG is already bypassed. */
-        if (err_flags && pg->bypassed)
+        /*
+         * If requested, retry pg_init until maximum number of retries exceeded.
+         * If retry not requested and PG already bypassed, always fail the path.
+         */
+        if (err_flags & MP_RETRY) {
+                if (pg_init_limit_reached(m, pgpath))
+                        err_flags |= MP_FAIL_PATH;
+        } else if (err_flags && pg->bypassed)
                 err_flags |= MP_FAIL_PATH;
 
         if (err_flags & MP_FAIL_PATH)
@@ -996,7 +1052,7 @@ void dm_pg_init_complete(struct dm_path *path, unsigned err_flags)
                 bypass_pg(m, pg, 1);
 
         spin_lock_irqsave(&m->lock, flags);
-        if (err_flags) {
+        if (err_flags & ~MP_RETRY) {
                 m->current_pgpath = NULL;
                 m->current_pg = NULL;
         } else if (!m->pg_init_required)
@@ -1148,11 +1204,15 @@ static int multipath_status(struct dm_target *ti, status_type_t type,
 
         /* Features */
         if (type == STATUSTYPE_INFO)
-                DMEMIT("1 %u ", m->queue_size);
-        else if (m->queue_if_no_path)
-                DMEMIT("1 queue_if_no_path ");
-        else
-                DMEMIT("0 ");
+                DMEMIT("2 %u %u ", m->queue_size, m->pg_init_count);
+        else {
+                DMEMIT("%u ", m->queue_if_no_path +
+                              (m->pg_init_retries > 0) * 2);
+                if (m->queue_if_no_path)
+                        DMEMIT("queue_if_no_path ");
+                if (m->pg_init_retries)
+                        DMEMIT("pg_init_retries %u ", m->pg_init_retries);
+        }
 
         if (hwh->type && hwh->type->status)
                 sz += hwh->type->status(hwh, type, result + sz, maxlen - sz);