LU-354 test: Change dev_set_rdonly() check to warning

[fs/lustre-release.git] / lustre / kernel_patches / patches / dev_read_only-2.6.18-vanilla.patch

diff --git a/lustre/kernel_patches/patches/dev_read_only-2.6.18-vanilla.patch b/lustre/kernel_patches/patches/dev_read_only-2.6.18-vanilla.patch
index b4704a5..a12fb3f 100644 (file)
--- a/lustre/kernel_patches/patches/dev_read_only-2.6.18-vanilla.patch
+++ b/lustre/kernel_patches/patches/dev_read_only-2.6.18-vanilla.patch
@@ -1,3 +1,24 @@
+This patch is no longer needed for Lustre.  It is only included
+for testing and ease of using the same kernel with older Lustre
+versions.  This testing functionality was replaced in Linux 3.0
+by the dm-flakey driver.
+
+This functionality is mainly used during testing, in order to
+simulate a server crash for ldiskfs by discarding all of the
+writes to the filesystem.  For recovery testing we could simulate
+this by using a special loopback or DM device that also discards
+writes to the device.
+
+This functionality is also used by target "failback" in order
+to speed up service shutdown and takeover by the other node
+during controlled operation.  However, it would also be possible
+to do this by simply allowing all of the in-flight requests to
+complete and then waiting for the service to stop.  This will
+also be needed by the DMU-OSD, because discarding of writes on
+a DMU-based target is not safe as it could trigger a storage
+failure if the data is ever read from disk again and the
+checksum does not match that expected by the block pointer.
+
 Index: linux-2.6.18.1/block/ll_rw_blk.c
 ===================================================================
 --- linux-2.6.18.1.orig/block/ll_rw_blk.c
@@ -15,13 +36,13 @@ Index: linux-2.6.18.1/block/ll_rw_blk.c
  
                if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)))
                        goto end_io;
-+              /* this is cfs's dev_rdonly check */
-+              if (bio->bi_rw == WRITE &&
-+                              dev_check_rdonly(bio->bi_bdev)) {
-+                      bio_endio(bio, bio->bi_size, 0);
-+                      break;
-+              }
- 
+
++               /* this is cfs's dev_rdonly check */
++               if (bio_rw(bio) == WRITE && dev_check_rdonly(bio->bi_bdev)) {
++                       bio_endio(bio, bio->bi_size, 0);
++                       break;
++               }
++
                /*
                 * If this device has partitions, remap block n
 @@ -3765,6 +3773,91 @@ void swap_io_context(struct io_context *