[PATCH] device-mapper: handle __lock_fs error

Handle error from __lock_fs()

Signed-Off-By: Alasdair G Kergon <agk@redhat.com>
From: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 14 insertions, 8 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 9687a084b5ff..83f53a46c2d4 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1048,6 +1048,7 @@ int dm_suspend(struct mapped_device *md)
 {
         struct dm_table *map;
         DECLARE_WAITQUEUE(wait, current);
+        int error;
 
         /* Flush I/O to the device. */
         down_read(&md->lock);
@@ -1056,25 +1057,29 @@ int dm_suspend(struct mapped_device *md)
                 return -EINVAL;
         }
 
+        error = __lock_fs(md);
+        if (error) {
+                up_read(&md->lock);
+                return error;
+        }
+
         map = dm_get_table(md);
         if (map)
                 dm_table_presuspend_targets(map);
-        __lock_fs(md);
 
         up_read(&md->lock);
 
         /*
-         * First we set the BLOCK_IO flag so no more ios will be
-         * mapped.
+         * First we set the BLOCK_IO flag so no more ios will be mapped.
+         *
+         * If the flag is already set we know another thread is trying to
+         * suspend as well, so we leave the fs locked for this thread.
          */
         down_write(&md->lock);
         if (test_bit(DMF_BLOCK_IO, &md->flags)) {
-                /*
-                 * If we get here we know another thread is
-                 * trying to suspend as well, so we leave the fs
-                 * locked for this thread.
-                 */
                 up_write(&md->lock);
+                if (map)
+                        dm_table_put(map);
                 return -EINVAL;
         }
 
@@ -1107,6 +1112,7 @@ int dm_suspend(struct mapped_device *md)
 
         /* were we interrupted ? */
         if (atomic_read(&md->pending)) {
+                /* FIXME Undo the presuspend_targets */
                 __unlock_fs(md);
                 clear_bit(DMF_BLOCK_IO, &md->flags);
                 up_write(&md->lock);