3.17-stable patches

added patches:
	dm-thin-grab-a-virtual-cell-before-looking-up-the-mapping.patch
	fix-thinko-in-iov_iter_single_seg_count.patch

diff --git a/queue-3.17/dm-thin-grab-a-virtual-cell-before-looking-up-the-mapping.patch b/queue-3.17/dm-thin-grab-a-virtual-cell-before-looking-up-the-mapping.patch
new file mode 100644 (file)
index 0000000..6c84c2c
--- /dev/null
+++ b/queue-3.17/dm-thin-grab-a-virtual-cell-before-looking-up-the-mapping.patch
@@ -0,0 +1,75 @@
+From c822ed967cba38505713d59ed40a114386ef6c01 Mon Sep 17 00:00:00 2001
+From: Joe Thornber <ejt@redhat.com>
+Date: Fri, 10 Oct 2014 09:41:09 +0100
+Subject: dm thin: grab a virtual cell before looking up the mapping
+
+From: Joe Thornber <ejt@redhat.com>
+
+commit c822ed967cba38505713d59ed40a114386ef6c01 upstream.
+
+Avoids normal IO racing with discard.
+
+Signed-off-by: Joe Thornber <ejt@redhat.com>
+Signed-off-by: Mike Snitzer <snitzer@redhat.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/md/dm-thin.c |   16 ++++++++++++----
+ 1 file changed, 12 insertions(+), 4 deletions(-)
+
+--- a/drivers/md/dm-thin.c
++++ b/drivers/md/dm-thin.c
+@@ -1936,6 +1936,14 @@ static int thin_bio_map(struct dm_target
+               return DM_MAPIO_SUBMITTED;
+       }
+ 
++      /*
++       * We must hold the virtual cell before doing the lookup, otherwise
++       * there's a race with discard.
++       */
++      build_virtual_key(tc->td, block, &key);
++      if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1, &cell_result))
++              return DM_MAPIO_SUBMITTED;
++
+       r = dm_thin_find_block(td, block, 0, &result);
+ 
+       /*
+@@ -1959,13 +1967,10 @@ static int thin_bio_map(struct dm_target
+                        * shared flag will be set in their case.
+                        */
+                       thin_defer_bio(tc, bio);
++                      cell_defer_no_holder_no_free(tc, &cell1);
+                       return DM_MAPIO_SUBMITTED;
+               }
+ 
+-              build_virtual_key(tc->td, block, &key);
+-              if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1, &cell_result))
+-                      return DM_MAPIO_SUBMITTED;
+-
+               build_data_key(tc->td, result.block, &key);
+               if (dm_bio_detain(tc->pool->prison, &key, bio, &cell2, &cell_result)) {
+                       cell_defer_no_holder_no_free(tc, &cell1);
+@@ -1986,6 +1991,7 @@ static int thin_bio_map(struct dm_target
+                        * of doing so.
+                        */
+                       handle_unserviceable_bio(tc->pool, bio);
++                      cell_defer_no_holder_no_free(tc, &cell1);
+                       return DM_MAPIO_SUBMITTED;
+               }
+               /* fall through */
+@@ -1996,6 +2002,7 @@ static int thin_bio_map(struct dm_target
+                * provide the hint to load the metadata into cache.
+                */
+               thin_defer_bio(tc, bio);
++              cell_defer_no_holder_no_free(tc, &cell1);
+               return DM_MAPIO_SUBMITTED;
+ 
+       default:
+@@ -2005,6 +2012,7 @@ static int thin_bio_map(struct dm_target
+                * pool is switched to fail-io mode.
+                */
+               bio_io_error(bio);
++              cell_defer_no_holder_no_free(tc, &cell1);
+               return DM_MAPIO_SUBMITTED;
+       }
+ }

diff --git a/queue-3.17/fix-thinko-in-iov_iter_single_seg_count.patch b/queue-3.17/fix-thinko-in-iov_iter_single_seg_count.patch
new file mode 100644 (file)
index 0000000..52340a8
--- /dev/null
+++ b/queue-3.17/fix-thinko-in-iov_iter_single_seg_count.patch
@@ -0,0 +1,45 @@
+From ad0eab9293485d1c06237e9249f6d4dfa3d93d4d Mon Sep 17 00:00:00 2001
+From: Paul Mackerras <paulus@samba.org>
+Date: Thu, 13 Nov 2014 20:15:23 +1100
+Subject: Fix thinko in iov_iter_single_seg_count
+
+From: Paul Mackerras <paulus@samba.org>
+
+commit ad0eab9293485d1c06237e9249f6d4dfa3d93d4d upstream.
+
+The branches of the if (i->type & ITER_BVEC) statement in
+iov_iter_single_seg_count() are the wrong way around; if ITER_BVEC is
+clear then we use i->bvec, when we should be using i->iov.  This fixes
+it.
+
+In my case, the symptom that this caused was that a KVM guest doing
+filesystem operations on a virtual disk would result in one of qemu's
+threads on the host going into an infinite loop in
+generic_perform_write().  The loop would hit the copied == 0 case and
+call iov_iter_single_seg_count() to reduce the number of bytes to try
+to process, but because of the error, iov_iter_single_seg_count()
+would just return i->count and the loop made no progress and continued
+forever.
+
+Signed-off-by: Paul Mackerras <paulus@samba.org>
+Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ mm/iov_iter.c |    4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/mm/iov_iter.c
++++ b/mm/iov_iter.c
+@@ -699,9 +699,9 @@ size_t iov_iter_single_seg_count(const s
+       if (i->nr_segs == 1)
+               return i->count;
+       else if (i->type & ITER_BVEC)
+-              return min(i->count, i->iov->iov_len - i->iov_offset);
+-      else
+               return min(i->count, i->bvec->bv_len - i->iov_offset);
++      else
++              return min(i->count, i->iov->iov_len - i->iov_offset);
+ }
+ EXPORT_SYMBOL(iov_iter_single_seg_count);
+ 

diff --git a/queue-3.17/series b/queue-3.17/series
index ef0a7eaf480b23f0137dc8ddfb68f443fa7d9f52..75a49933b1b0743faeed5b8cf8b854877aad8281 100644 (file)
--- a/queue-3.17/series
+++ b/queue-3.17/series
@@ -72,3 +72,5 @@ arm-8191-1-decompressor-ensure-i-side-picks-up-relocated-code.patch
 arm-dts-am335x-evm-fix-5th-nand-partition-s-name.patch
 arm-mvebu-armada-xp-generalize-use-of-i2c-quirk.patch
 pinctrl-dra-dt-bindings-fix-output-pull-up-down.patch
+fix-thinko-in-iov_iter_single_seg_count.patch
+dm-thin-grab-a-virtual-cell-before-looking-up-the-mapping.patch