b=17895

i=adilger
i=alex

While using HA for Lustre servers with Linux RAID, it is possible that MMP will not detect multiple mounts. To make this work we need to unplug the device queue in RAID when the MMP block is being written. Also while reading the MMP block, we should read it from disk and not the cached one.

diff --git a/lustre/ChangeLog b/lustre/ChangeLog
index 5db2ee0..2d6cf88 100644 (file)
--- a/lustre/ChangeLog
+++ b/lustre/ChangeLog
@@ -1931,6 +1931,16 @@ Details    : enable OBD_CONNECT_MDT flag when connecting from the MDS so that
             from a different NID, so we do not need to wait for the export to be
             evicted
 
+Severity   : major
+Frequency  : rare, only if using MMP with Linux RAID
+Bugzilla   : 17895
+Description: MMP doesn't work with Linux RAID
+Details    : While using HA for Lustre servers with Linux RAID, it is possible
+             that MMP will not detect multiple mounts. To make this work we
+             need to unplug the device queue in RAID when the MMP block is being
+             written. Also while reading the MMP block, we should read it from
+             disk and not the cached one.
+
 --------------------------------------------------------------------------------
 
 2007-08-10         Cluster File Systems, Inc. <info@clusterfs.com>

diff --git a/lustre/kernel_patches/patches/md-mmp-unplug-dev-sles10.patch b/lustre/kernel_patches/patches/md-mmp-unplug-dev-sles10.patch
new file mode 100644 (file)
index 0000000..8bfdef3
--- /dev/null
+++ b/lustre/kernel_patches/patches/md-mmp-unplug-dev-sles10.patch
@@ -0,0 +1,22 @@
+Index: linux-2.6.16.60-0.33/drivers/md/raid5.c
+===================================================================
+--- linux-2.6.16.60-0.33.orig/drivers/md/raid5.c
++++ linux-2.6.16.60-0.33/drivers/md/raid5.c
+@@ -900,6 +900,8 @@ static int add_stripe_bio(struct stripe_
+               bi->bi_next = *bip;
+       *bip = bi;
+       bi->bi_phys_segments ++;
++      if (bio_sync(bi) && !forwrite)
++              clear_bit(R5_UPTODATE, &sh->dev[dd_idx].flags); /* force to read from disk. */
+       spin_unlock_irq(&conf->device_lock);
+       spin_unlock(&sh->lock);
+ 
+@@ -1617,6 +1619,8 @@ static int make_request (request_queue_t
+               bi->bi_end_io(bi, bytes, 0);
+       }
+       spin_unlock_irq(&conf->device_lock);
++      if (bio_sync(bi))
++              raid5_unplug_device(q);
+       return 0;
+ }
+ 

diff --git a/lustre/kernel_patches/patches/md-mmp-unplug-dev.patch b/lustre/kernel_patches/patches/md-mmp-unplug-dev.patch
new file mode 100644 (file)
index 0000000..0334abd
--- /dev/null
+++ b/lustre/kernel_patches/patches/md-mmp-unplug-dev.patch
@@ -0,0 +1,22 @@
+Index: linux-2.6.22.14/drivers/md/raid5.c
+===================================================================
+--- linux-2.6.22.14.orig/drivers/md/raid5.c
++++ linux-2.6.22.14/drivers/md/raid5.c
+@@ -1268,6 +1268,8 @@ static int add_stripe_bio(struct stripe_
+               bi->bi_next = *bip;
+       *bip = bi;
+       bi->bi_phys_segments ++;
++      if (bio_sync(bi) && !forwrite)
++              clear_bit(R5_UPTODATE, &sh->dev[dd_idx].flags); /* force to read from disk. */
+       spin_unlock_irq(&conf->device_lock);
+       spin_unlock(&sh->lock);
+ 
+@@ -2972,6 +2974,8 @@ static int make_request(request_queue_t 
+                             test_bit(BIO_UPTODATE, &bi->bi_flags)
+                               ? 0 : -EIO);
+       }
++      if (bio_sync(bi))
++              raid5_unplug_device(q);
+       return 0;
+ }
+ 

diff --git a/lustre/kernel_patches/series/2.6-rhel5.series b/lustre/kernel_patches/series/2.6-rhel5.series
index 0fc2b97..97060fd 100644 (file)
--- a/lustre/kernel_patches/series/2.6-rhel5.series
+++ b/lustre/kernel_patches/series/2.6-rhel5.series
@@ -21,3 +21,4 @@ md-rebuild-policy.patch
 md-soft-lockups.patch
 jbd-journal-chksum-2.6.18-vanilla.patch
 quota-large-limits-rhel5.patch
+md-mmp-unplug-dev.patch

diff --git a/lustre/kernel_patches/series/2.6-sles10.series b/lustre/kernel_patches/series/2.6-sles10.series
index 070f943..dc85e99 100644 (file)
--- a/lustre/kernel_patches/series/2.6-sles10.series
+++ b/lustre/kernel_patches/series/2.6-sles10.series
@@ -16,3 +16,4 @@ proc-sleep-2.6.16-sles10.patch
 export-nr_free_buffer_pages.patch 
 fmode-exec-2.6-sles10.patch
 quota-large-limits-sles10.patch
+md-mmp-unplug-dev-sles10.patch

diff --git a/lustre/kernel_patches/series/2.6.22-vanilla.series b/lustre/kernel_patches/series/2.6.22-vanilla.series
index fe32803..6fad0bd 100644 (file)
--- a/lustre/kernel_patches/series/2.6.22-vanilla.series
+++ b/lustre/kernel_patches/series/2.6.22-vanilla.series
@@ -12,3 +12,4 @@ export-2.6.18-vanilla.patch
 export-show_task-2.6.18-vanilla.patch 
 sd_iostats-2.6.22-vanilla.patch
 quota-large-limits-rhel5.patch
+md-mmp-unplug-dev.patch