Merge branch 'splice-2.6.23' of git://git.kernel.dk/data/git/linux-2.6-block

[sfrench/cifs-2.6.git] / drivers / md / dm-mpath.c

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index cf8bf052138e5e9926912ef87098211de510558c..de54b39e6ffe9fb78cbad18c2a5d5b559d54d870 100644 (file)
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -31,7 +31,7 @@ struct pgpath {
        struct priority_group *pg;      /* Owning PG */
        unsigned fail_count;            /* Cumulative failure count */
 
-       struct path path;
+       struct dm_path path;
 };
 
 #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path)
@@ -229,7 +229,7 @@ static void __switch_pg(struct multipath *m, struct pgpath *pgpath)
 
 static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg)
 {
-       struct path *path;
+       struct dm_path *path;
 
        path = pg->ps.type->select_path(&pg->ps, &m->repeat_count);
        if (!path)
@@ -282,10 +282,27 @@ failed:
        m->current_pg = NULL;
 }
 
+/*
+ * Check whether bios must be queued in the device-mapper core rather
+ * than here in the target.
+ *
+ * m->lock must be held on entry.
+ *
+ * If m->queue_if_no_path and m->saved_queue_if_no_path hold the
+ * same value then we are not between multipath_presuspend()
+ * and multipath_resume() calls and we have no need to check
+ * for the DMF_NOFLUSH_SUSPENDING flag.
+ */
+static int __must_push_back(struct multipath *m)
+{
+       return (m->queue_if_no_path != m->saved_queue_if_no_path &&
+               dm_noflush_suspending(m->ti));
+}
+
 static int map_io(struct multipath *m, struct bio *bio, struct mpath_io *mpio,
                  unsigned was_queued)
 {
-       int r = 1;
+       int r = DM_MAPIO_REMAPPED;
        unsigned long flags;
        struct pgpath *pgpath;
 
@@ -310,11 +327,13 @@ static int map_io(struct multipath *m, struct bio *bio, struct mpath_io *mpio,
                    !m->queue_io)
                        queue_work(kmultipathd, &m->process_queued_ios);
                pgpath = NULL;
-               r = 0;
-       } else if (!pgpath)
-               r = -EIO;               /* Failed */
-       else
+               r = DM_MAPIO_SUBMITTED;
+       } else if (pgpath)
                bio->bi_bdev = pgpath->path.dev->bdev;
+       else if (__must_push_back(m))
+               r = DM_MAPIO_REQUEUE;
+       else
+               r = -EIO;       /* Failed */
 
        mpio->pgpath = pgpath;
 
@@ -372,8 +391,10 @@ static void dispatch_queued_ios(struct multipath *m)
                r = map_io(m, bio, mpio, 1);
                if (r < 0)
                        bio_endio(bio, bio->bi_size, r);
-               else if (r == 1)
+               else if (r == DM_MAPIO_REMAPPED)
                        generic_make_request(bio);
+               else if (r == DM_MAPIO_REQUEUE)
+                       bio_endio(bio, bio->bi_size, -EIO);
 
                bio = next;
        }
@@ -647,6 +668,9 @@ static int parse_hw_handler(struct arg_set *as, struct multipath *m)
                return -EINVAL;
        }
 
+       m->hw_handler.md = dm_table_get_md(ti->table);
+       dm_put(m->hw_handler.md);
+
        r = hwht->create(&m->hw_handler, hw_argc - 1, as->argv);
        if (r) {
                dm_put_hw_handler(hwht);
@@ -783,7 +807,7 @@ static int multipath_map(struct dm_target *ti, struct bio *bio,
        map_context->ptr = mpio;
        bio->bi_rw |= (1 << BIO_RW_FAILFAST);
        r = map_io(m, bio, mpio, 0);
-       if (r < 0)
+       if (r < 0 || r == DM_MAPIO_REQUEUE)
                mempool_free(mpio, m->mpio_pool);
 
        return r;
@@ -957,7 +981,7 @@ static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed)
 /*
  * pg_init must call this when it has completed its initialisation
  */
-void dm_pg_init_complete(struct path *path, unsigned err_flags)
+void dm_pg_init_complete(struct dm_path *path, unsigned err_flags)
 {
        struct pgpath *pgpath = path_to_pgpath(path);
        struct priority_group *pg = pgpath->pg;
@@ -1007,7 +1031,10 @@ static int do_end_io(struct multipath *m, struct bio *bio,
 
        spin_lock_irqsave(&m->lock, flags);
        if (!m->nr_valid_paths) {
-               if (!m->queue_if_no_path) {
+               if (__must_push_back(m)) {
+                       spin_unlock_irqrestore(&m->lock, flags);
+                       return DM_ENDIO_REQUEUE;
+               } else if (!m->queue_if_no_path) {
                        spin_unlock_irqrestore(&m->lock, flags);
                        return -EIO;
                } else {
@@ -1042,7 +1069,7 @@ static int do_end_io(struct multipath *m, struct bio *bio,
                queue_work(kmultipathd, &m->process_queued_ios);
        spin_unlock_irqrestore(&m->lock, flags);
 
-       return 1;       /* io not complete */
+       return DM_ENDIO_INCOMPLETE;     /* io not complete */
 }
 
 static int multipath_end_io(struct dm_target *ti, struct bio *bio,
@@ -1060,7 +1087,7 @@ static int multipath_end_io(struct dm_target *ti, struct bio *bio,
                if (ps->type->end_io)
                        ps->type->end_io(ps, &pgpath->path);
        }
-       if (r <= 0)
+       if (r != DM_ENDIO_INCOMPLETE)
                mempool_free(mpio, m->mpio_pool);
 
        return r;
@@ -1272,7 +1299,7 @@ static int multipath_ioctl(struct dm_target *ti, struct inode *inode,
        struct dentry fake_dentry = {};
        int r = 0;
 
-       fake_file.f_dentry = &fake_dentry;
+       fake_file.f_path.dentry = &fake_dentry;
 
        spin_lock_irqsave(&m->lock, flags);