[PATCH] dm table: add target preresume

This patch adds a target preresume hook.

It is called before the targets are resumed and if it returns an error the
resume gets cancelled.

The crypt target will use this to indicate that it is unable to process I/O
because no encryption key has been supplied.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 19 insertions, 4 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 75fe9493e6af..47412ae98fb9 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -939,9 +939,20 @@ void dm_table_postsuspend_targets(struct dm_table *t)
         return suspend_targets(t, 1);
 }
 
-void dm_table_resume_targets(struct dm_table *t)
+int dm_table_resume_targets(struct dm_table *t)
 {
-        int i;
+        int i, r = 0;
+
+        for (i = 0; i < t->num_targets; i++) {
+                struct dm_target *ti = t->targets + i;
+
+                if (!ti->type->preresume)
+                        continue;
+
+                r = ti->type->preresume(ti);
+                if (r)
+                        return r;
+        }
 
         for (i = 0; i < t->num_targets; i++) {
                 struct dm_target *ti = t->targets + i;
@@ -949,6 +960,8 @@ void dm_table_resume_targets(struct dm_table *t)
                 if (ti->type->resume)
                         ti->type->resume(ti);
         }
+
+        return 0;
 }
 
 int dm_table_any_congested(struct dm_table *t, int bdi_bits)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 883860c3565b..aeb63a3ac330 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1360,7 +1360,9 @@ int dm_resume(struct mapped_device *md)
         if (!map || !dm_table_get_size(map))
                 goto out;
 
-        dm_table_resume_targets(map);
+        r = dm_table_resume_targets(map);
+        if (r)
+                goto out;
 
         down_write(&md->io_lock);
         clear_bit(DMF_BLOCK_IO, &md->flags);
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index fe701c4834fe..a48ec5e3c1f4 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -57,7 +57,7 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q);
 struct list_head *dm_table_get_devices(struct dm_table *t);
 void dm_table_presuspend_targets(struct dm_table *t);
 void dm_table_postsuspend_targets(struct dm_table *t);
-void dm_table_resume_targets(struct dm_table *t);
+int dm_table_resume_targets(struct dm_table *t);
 int dm_table_any_congested(struct dm_table *t, int bdi_bits);
 void dm_table_unplug_all(struct dm_table *t);
 int dm_table_flush_all(struct dm_table *t);