Merge branch 'for-2.6.33' of git://git.kernel.dk/linux-2.6-block

* 'for-2.6.33' of git://git.kernel.dk/linux-2.6-block: (113 commits)
  cfq-iosched: Do not access cfqq after freeing it
  block: include linux/err.h to use ERR_PTR
  cfq-iosched: use call_rcu() instead of doing grace period stall on queue exit
  blkio: Allow CFQ group IO scheduling even when CFQ is a module
  blkio: Implement dynamic io controlling policy registration
  blkio: Export some symbols from blkio as its user CFQ can be a module
  block: Fix io_context leak after failure of clone with CLONE_IO
  block: Fix io_context leak after clone with CLONE_IO
  cfq-iosched: make nonrot check logic consistent
  io controller: quick fix for blk-cgroup and modular CFQ
  cfq-iosched: move IO controller declerations to a header file
  cfq-iosched: fix compile problem with !CONFIG_CGROUP
  blkio: Documentation
  blkio: Wait on sync-noidle queue even if rq_noidle = 1
  blkio: Implement group_isolation tunable
  blkio: Determine async workload length based on total number of queues
  blkio: Wait for cfq queue to get backlogged if group is empty
  blkio: Propagate cgroup weight updation to cfq groups
  blkio: Drop the reference to queue once the task changes cgroup
  blkio: Provide some isolation between groups
  ...

Documentation/blockdev/drbd/README.txt

@@ -0,0 +1,16 @@
+Description
+
+  DRBD is a shared-nothing, synchronously replicated block device. It
+  is designed to serve as a building block for high availability
+  clusters and in this context, is a "drop-in" replacement for shared
+  storage. Simplistically, you could see it as a network RAID 1.
+
+  Please visit http://www.drbd.org to find out more.
+
+The here included files are intended to help understand the implementation
+
+DRBD-8.3-data-packets.svg, DRBD-data-packets.svg  
+  relates some functions, and write packets.
+
+conn-states-8.dot, disk-states-8.dot, node-states-8.dot
+  The sub graphs of DRBD's state transitions

Documentation/blockdev/drbd/conn-states-8.dot

@@ -0,0 +1,18 @@
+digraph conn_states {
+	StandAllone  -> WFConnection   [ label = "ioctl_set_net()" ]
+	WFConnection -> Unconnected    [ label = "unable to bind()" ]
+	WFConnection -> WFReportParams [ label = "in connect() after accept" ]
+	WFReportParams -> StandAllone  [ label = "checks in receive_param()" ]
+	WFReportParams -> Connected    [ label = "in receive_param()" ]
+	WFReportParams -> WFBitMapS    [ label = "sync_handshake()" ]
+	WFReportParams -> WFBitMapT    [ label = "sync_handshake()" ]
+	WFBitMapS -> SyncSource        [ label = "receive_bitmap()" ]
+	WFBitMapT -> SyncTarget        [ label = "receive_bitmap()" ]
+	SyncSource -> Connected
+	SyncTarget -> Connected
+	SyncSource -> PausedSyncS
+	SyncTarget -> PausedSyncT
+	PausedSyncS -> SyncSource
+	PausedSyncT -> SyncTarget
+	Connected   -> WFConnection    [ label = "* on network error" ]
+}

Documentation/blockdev/drbd/disk-states-8.dot

@@ -0,0 +1,16 @@
+digraph disk_states {
+	Diskless -> Inconsistent       [ label = "ioctl_set_disk()" ]
+	Diskless -> Consistent         [ label = "ioctl_set_disk()" ]
+	Diskless -> Outdated           [ label = "ioctl_set_disk()" ]
+	Consistent -> Outdated         [ label = "receive_param()" ]
+	Consistent -> UpToDate         [ label = "receive_param()" ]
+	Consistent -> Inconsistent     [ label = "start resync" ]
+	Outdated   -> Inconsistent     [ label = "start resync" ]
+	UpToDate   -> Inconsistent     [ label = "ioctl_replicate" ]
+	Inconsistent -> UpToDate       [ label = "resync completed" ]
+	Consistent -> Failed           [ label = "io completion error" ]
+	Outdated   -> Failed           [ label = "io completion error" ]
+	UpToDate   -> Failed           [ label = "io completion error" ]
+	Inconsistent -> Failed         [ label = "io completion error" ]
+	Failed -> Diskless             [ label = "sending notify to peer" ]
+}

Documentation/blockdev/drbd/drbd-connection-state-overview.dot

@@ -0,0 +1,85 @@
+// vim: set sw=2 sts=2 :
+digraph {
+  rankdir=BT
+  bgcolor=white
+
+  node [shape=plaintext]
+  node [fontcolor=black]
+
+  StandAlone     [ style=filled,fillcolor=gray,label=StandAlone ]
+
+  node [fontcolor=lightgray]
+
+  Unconnected    [ label=Unconnected ]
+
+  CommTrouble [ shape=record,
+    label="{communication loss|{Timeout|BrokenPipe|NetworkFailure}}" ]
+
+  node [fontcolor=gray]
+
+  subgraph cluster_try_connect {
+    label="try to connect, handshake"
+    rank=max
+    WFConnection   [ label=WFConnection ]
+    WFReportParams [ label=WFReportParams ]
+  }
+
+  TearDown       [ label=TearDown ]
+
+  Connected      [ label=Connected,style=filled,fillcolor=green,fontcolor=black ]
+
+  node [fontcolor=lightblue]
+
+  StartingSyncS  [ label=StartingSyncS ]
+  StartingSyncT  [ label=StartingSyncT ]
+
+  subgraph cluster_bitmap_exchange {
+    node [fontcolor=red]
+    fontcolor=red
+    label="new application (WRITE?) requests blocked\lwhile bitmap is exchanged"
+
+    WFBitMapT      [ label=WFBitMapT ]
+    WFSyncUUID     [ label=WFSyncUUID ]
+    WFBitMapS      [ label=WFBitMapS ]
+  }
+
+  node [fontcolor=blue]
+
+  cluster_resync [ shape=record,label="{<any>resynchronisation process running\l'concurrent' application requests allowed|{{<T>PausedSyncT\nSyncTarget}|{<S>PausedSyncS\nSyncSource}}}" ]
+
+  node [shape=box,fontcolor=black]
+
+  // drbdadm [label="drbdadm connect"]
+  // handshake [label="drbd_connect()\ndrbd_do_handshake\ndrbd_sync_handshake() etc."]
+  // comm_error [label="communication trouble"]
+
+  //
+  // edges
+  // --------------------------------------
+
+  StandAlone -> Unconnected [ label="drbdadm connect" ]
+  Unconnected -> StandAlone  [ label="drbdadm disconnect\lor serious communication trouble" ]
+  Unconnected -> WFConnection [ label="receiver thread is started" ]
+  WFConnection -> WFReportParams [ headlabel="accept()\land/or                        \lconnect()\l" ]
+
+  WFReportParams -> StandAlone [ label="during handshake\lpeers do not agree\labout something essential" ]
+  WFReportParams -> Connected [ label="data identical\lno sync needed",color=green,fontcolor=green ]
+
+    WFReportParams -> WFBitMapS
+    WFReportParams -> WFBitMapT
+    WFBitMapT -> WFSyncUUID [minlen=0.1,constraint=false]
+
+      WFBitMapS -> cluster_resync:S
+      WFSyncUUID -> cluster_resync:T
+
+  edge [color=green]
+  cluster_resync:any -> Connected [ label="resnyc done",fontcolor=green ]
+
+  edge [color=red]
+  WFReportParams -> CommTrouble
+  Connected -> CommTrouble
+  cluster_resync:any -> CommTrouble
+  edge [color=black]
+  CommTrouble -> Unconnected [label="receiver thread is stopped" ]
+
+}

Documentation/blockdev/drbd/node-states-8.dot

@@ -0,0 +1,14 @@
+digraph node_states {
+	Secondary -> Primary           [ label = "ioctl_set_state()" ]
+	Primary   -> Secondary 	       [ label = "ioctl_set_state()" ]
+}
+
+digraph peer_states {
+	Secondary -> Primary           [ label = "recv state packet" ]
+	Primary   -> Secondary 	       [ label = "recv state packet" ]
+	Primary   -> Unknown 	       [ label = "connection lost" ]
+	Secondary  -> Unknown  	       [ label = "connection lost" ]
+	Unknown   -> Primary           [ label = "connected" ]
+	Unknown   -> Secondary         [ label = "connected" ]
+}
+

Documentation/cgroups/blkio-controller.txt

@@ -0,0 +1,135 @@
+				Block IO Controller
+				===================
+Overview
+========
+cgroup subsys "blkio" implements the block io controller. There seems to be
+a need of various kinds of IO control policies (like proportional BW, max BW)
+both at leaf nodes as well as at intermediate nodes in a storage hierarchy.
+Plan is to use the same cgroup based management interface for blkio controller
+and based on user options switch IO policies in the background.
+
+In the first phase, this patchset implements proportional weight time based
+division of disk policy. It is implemented in CFQ. Hence this policy takes
+effect only on leaf nodes when CFQ is being used.
+
+HOWTO
+=====
+You can do a very simple testing of running two dd threads in two different
+cgroups. Here is what you can do.
+
+- Enable group scheduling in CFQ
+	CONFIG_CFQ_GROUP_IOSCHED=y
+
+- Compile and boot into kernel and mount IO controller (blkio).
+
+	mount -t cgroup -o blkio none /cgroup
+
+- Create two cgroups
+	mkdir -p /cgroup/test1/ /cgroup/test2
+
+- Set weights of group test1 and test2
+	echo 1000 > /cgroup/test1/blkio.weight
+	echo 500 > /cgroup/test2/blkio.weight
+
+- Create two same size files (say 512MB each) on same disk (file1, file2) and
+  launch two dd threads in different cgroup to read those files.
+
+	sync
+	echo 3 > /proc/sys/vm/drop_caches
+
+	dd if=/mnt/sdb/zerofile1 of=/dev/null &
+	echo $! > /cgroup/test1/tasks
+	cat /cgroup/test1/tasks
+
+	dd if=/mnt/sdb/zerofile2 of=/dev/null &
+	echo $! > /cgroup/test2/tasks
+	cat /cgroup/test2/tasks
+
+- At macro level, first dd should finish first. To get more precise data, keep
+  on looking at (with the help of script), at blkio.disk_time and
+  blkio.disk_sectors files of both test1 and test2 groups. This will tell how
+  much disk time (in milli seconds), each group got and how many secotors each
+  group dispatched to the disk. We provide fairness in terms of disk time, so
+  ideally io.disk_time of cgroups should be in proportion to the weight.
+
+Various user visible config options
+===================================
+CONFIG_CFQ_GROUP_IOSCHED
+	- Enables group scheduling in CFQ. Currently only 1 level of group
+	  creation is allowed.
+
+CONFIG_DEBUG_CFQ_IOSCHED
+	- Enables some debugging messages in blktrace. Also creates extra
+	  cgroup file blkio.dequeue.
+
+Config options selected automatically
+=====================================
+These config options are not user visible and are selected/deselected
+automatically based on IO scheduler configuration.
+
+CONFIG_BLK_CGROUP
+	- Block IO controller. Selected by CONFIG_CFQ_GROUP_IOSCHED.
+
+CONFIG_DEBUG_BLK_CGROUP
+	- Debug help. Selected by CONFIG_DEBUG_CFQ_IOSCHED.
+
+Details of cgroup files
+=======================
+- blkio.weight
+	- Specifies per cgroup weight.
+
+	  Currently allowed range of weights is from 100 to 1000.
+
+- blkio.time
+	- disk time allocated to cgroup per device in milliseconds. First
+	  two fields specify the major and minor number of the device and
+	  third field specifies the disk time allocated to group in
+	  milliseconds.
+
+- blkio.sectors
+	- number of sectors transferred to/from disk by the group. First
+	  two fields specify the major and minor number of the device and
+	  third field specifies the number of sectors transferred by the
+	  group to/from the device.
+
+- blkio.dequeue
+	- Debugging aid only enabled if CONFIG_DEBUG_CFQ_IOSCHED=y. This
+	  gives the statistics about how many a times a group was dequeued
+	  from service tree of the device. First two fields specify the major
+	  and minor number of the device and third field specifies the number
+	  of times a group was dequeued from a particular device.
+
+CFQ sysfs tunable
+=================
+/sys/block/<disk>/queue/iosched/group_isolation
+
+If group_isolation=1, it provides stronger isolation between groups at the
+expense of throughput. By default group_isolation is 0. In general that
+means that if group_isolation=0, expect fairness for sequential workload
+only. Set group_isolation=1 to see fairness for random IO workload also.
+
+Generally CFQ will put random seeky workload in sync-noidle category. CFQ
+will disable idling on these queues and it does a collective idling on group
+of such queues. Generally these are slow moving queues and if there is a
+sync-noidle service tree in each group, that group gets exclusive access to
+disk for certain period. That means it will bring the throughput down if
+group does not have enough IO to drive deeper queue depths and utilize disk
+capacity to the fullest in the slice allocated to it. But the flip side is
+that even a random reader should get better latencies and overall throughput
+if there are lots of sequential readers/sync-idle workload running in the
+system.
+
+If group_isolation=0, then CFQ automatically moves all the random seeky queues
+in the root group. That means there will be no service differentiation for
+that kind of workload. This leads to better throughput as we do collective
+idling on root sync-noidle tree.
+
+By default one should run with group_isolation=0. If that is not sufficient
+and one wants stronger isolation between groups, then set group_isolation=1
+but this will come at cost of reduced throughput.
+
+What works
+==========
+- Currently only sync IO queues are support. All the buffered writes are
+  still system wide and not per group. Hence we will not see service
+  differentiation between buffered writes between groups.

MAINTAINERS

@@ -1848,6 +1848,19 @@ S:	Maintained
 F:	drivers/scsi/dpt*
 F:	drivers/scsi/dpt/
 
+DRBD DRIVER
+P:     Philipp Reisner
+P:     Lars Ellenberg
+M:     drbd-dev@lists.linbit.com
+L:     drbd-user@lists.linbit.com
+W:     http://www.drbd.org
+T:     git git://git.drbd.org/linux-2.6-drbd.git drbd
+T:     git git://git.drbd.org/drbd-8.3.git
+S:     Supported
+F:     drivers/block/drbd/
+F:     lib/lru_cache.c
+F:     Documentation/blockdev/drbd/
+
 DRIVER CORE, KOBJECTS, AND SYSFS
 M:	Greg Kroah-Hartman <gregkh@suse.de>
 T:	quilt kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/

arch/alpha/include/asm/cacheflush.h

@@ -9,6 +9,7 @@
 #define flush_cache_dup_mm(mm)			do { } while (0)
 #define flush_cache_range(vma, start, end)	do { } while (0)
 #define flush_cache_page(vma, vmaddr, pfn)	do { } while (0)
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 #define flush_dcache_page(page)			do { } while (0)
 #define flush_dcache_mmap_lock(mapping)		do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)	do { } while (0)

arch/arm/include/asm/cacheflush.h

@@ -418,6 +418,7 @@ extern void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
  * about to change to user space.  This is the same method as used on SPARC64.
  * See update_mmu_cache for the user space part.
  */
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 extern void flush_dcache_page(struct page *);
 
 static inline void __flush_icache_all(void)

arch/avr32/include/asm/cacheflush.h

@@ -107,6 +107,7 @@ extern void flush_icache_page(struct vm_area_struct *vma, struct page *page);
  * do something here, but only for certain configurations.  No such
  * configurations exist at this time.
  */
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 #define flush_dcache_page(page)			do { } while (0)
 #define flush_dcache_mmap_lock(page)		do { } while (0)
 #define flush_dcache_mmap_unlock(page)		do { } while (0)

arch/blackfin/include/asm/cacheflush.h

@@ -68,9 +68,11 @@ do { memcpy(dst, src, len);						\
 #endif
 #if defined(CONFIG_BFIN_EXTMEM_WRITEBACK) || defined(CONFIG_BFIN_L2_WRITEBACK)
 # define flush_dcache_range(start,end)		blackfin_dcache_flush_range((start), (end))
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 # define flush_dcache_page(page)		blackfin_dflush_page(page_address(page))
 #else
 # define flush_dcache_range(start,end)		do { } while (0)
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 # define flush_dcache_page(page)		do { } while (0)
 #endif
 

arch/cris/include/asm/cacheflush.h

@@ -12,6 +12,7 @@
 #define flush_cache_dup_mm(mm)			do { } while (0)
 #define flush_cache_range(vma, start, end)	do { } while (0)
 #define flush_cache_page(vma, vmaddr, pfn)	do { } while (0)
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 #define flush_dcache_page(page)			do { } while (0)
 #define flush_dcache_mmap_lock(mapping)		do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)	do { } while (0)

arch/frv/include/asm/cacheflush.h

@@ -47,6 +47,7 @@ static inline void __flush_cache_all(void)
 }
 
 /* dcache/icache coherency... */
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 #ifdef CONFIG_MMU
 extern void flush_dcache_page(struct page *page);
 #else

arch/h8300/include/asm/cacheflush.h

@@ -15,6 +15,7 @@
 #define	flush_cache_dup_mm(mm)		do { } while (0)
 #define	flush_cache_range(vma,a,b)
 #define	flush_cache_page(vma,p,pfn)
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
 #define	flush_dcache_page(page)
 #define	flush_dcache_mmap_lock(mapping)
 #define	flush_dcache_mmap_unlock(mapping)

arch/ia64/include/asm/cacheflush.h

@@ -25,6 +25,7 @@
 #define flush_cache_vmap(start, end)		do { } while (0)
 #define flush_cache_vunmap(start, end)		do { } while (0)
 
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 #define flush_dcache_page(page)			\
 do {						\
 	clear_bit(PG_arch_1, &(page)->flags);	\