- dev_read_only patch against 2.6.0-test6

NOTE: it differs from 2.4's patch:
      1) struct block_device * must be passed instead of kdev_t
      2) dev_set_rdonly() sets flag in request queue. after that
         queue becomes rdonly

diff --git a/lustre/kernel_patches/patches/dev_read_only_2.6.0.patch b/lustre/kernel_patches/patches/dev_read_only_2.6.0.patch
new file mode 100644 (file)
index 0000000..f0f79df
--- /dev/null
+++ b/lustre/kernel_patches/patches/dev_read_only_2.6.0.patch
@@ -0,0 +1,81 @@
+ drivers/block/ll_rw_blk.c |   49 ++++++++++++++++++++++++++++++++++++++++++++++
+ include/linux/blkdev.h    |    1 
+ 2 files changed, 50 insertions(+)
+
+--- linux-2.6.0-test6/drivers/block/ll_rw_blk.c~dev_read_only_2.6.0    2003-10-14 19:56:55.000000000 +0400
++++ linux-2.6.0-test6-alexey/drivers/block/ll_rw_blk.c 2003-10-22 01:35:56.000000000 +0400
+@@ -2213,6 +2213,9 @@ end_io:
+ 
+               if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))
+                       goto end_io;
++              if (test_bit(QUEUE_FLAG_RDONLY, &q->queue_flags)
++                              && bio->bi_rw == WRITE)
++                      goto end_io;
+ 
+               /*
+                * If this device has partitions, remap block n
+@@ -2867,6 +2870,52 @@ void blk_unregister_queue(struct gendisk
+       }
+ }
+ 
++#define MAX_RDONLY_DEVS               16
++
++static struct block_device *rdonly_devs[MAX_RDONLY_DEVS] = {0, };
++
++/*
++ * Debug code for turning block devices "read-only" (will discard writes
++ * silently).  This is for filesystem crash/recovery testing.
++ */
++void dev_set_rdonly(struct block_device *bdev, int no_write)
++{
++      if (bdev) {
++              request_queue_t *q;
++
++              q = bdev_get_queue(bdev);
++              if (!q) {
++                      printk(KERN_ERR
++                              "dev_set_rdonly() for non-existing device\n");
++                      return;
++              }
++              printk(KERN_WARNING "Turning device %s read-only\n",
++                              bdev->bd_disk ? bdev->bd_disk->disk_name : "?");
++              set_bit(QUEUE_FLAG_RDONLY, &q->queue_flags);
++              rdonly_devs[no_write] = bdev;
++      }
++}
++
++void dev_clear_rdonly(int no_write)
++{
++      request_queue_t *q;
++      
++      if (rdonly_devs[no_write] == NULL)
++              return;
++      
++      q = bdev_get_queue(rdonly_devs[no_write]);
++      if (!q) {
++              printk(KERN_ERR
++                      "dev_clear_rdonly: no queue for device at slot %d\n",
++                      no_write);
++              return;
++      }
++      clear_bit(QUEUE_FLAG_RDONLY, &q->queue_flags);
++      rdonly_devs[no_write] = NULL;
++}
++
++EXPORT_SYMBOL(dev_set_rdonly);
++EXPORT_SYMBOL(dev_clear_rdonly);
+ 
+ EXPORT_SYMBOL(process_that_request_first);
+ EXPORT_SYMBOL(end_that_request_first);
+--- linux-2.6.0-test6/include/linux/blkdev.h~dev_read_only_2.6.0       2003-10-14 19:57:05.000000000 +0400
++++ linux-2.6.0-test6-alexey/include/linux/blkdev.h    2003-10-21 23:31:18.000000000 +0400
+@@ -367,6 +367,7 @@ struct request_queue
+ #define       QUEUE_FLAG_READFULL     3       /* write queue has been filled */
+ #define QUEUE_FLAG_WRITEFULL  4       /* read queue has been filled */
+ #define QUEUE_FLAG_DEAD               5       /* queue being torn down */
++#define QUEUE_FLAG_RDONLY     6       /* queue accepts reads only */
+ 
+ #define blk_queue_plugged(q)  !list_empty(&(q)->plug_list)
+ #define blk_queue_tagged(q)   test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
+
+_