[PATCH 000 of 29] md: Introduction : patchbomb for 2.6.27 merge window

[PATCH 000 of 29] md: Introduction : patchbomb for 2.6.27 merge window

[NeilBrown]

Following are 29 patches for md suitable for 2.6.27.

The first three are for bugs that can trigger oops or data corruption.
They are possibly suitable for 2.6.26 and for -stable.

There are some bug fixes, some minor feature enhancement (mostly
related to sysfs control of arrays) and some raid5 cleanups

Thanks,
NeilBrown


 [PATCH 001 of 29] md: Ensure interrupted recovery completed properly (v1 metadata plus bitmap)
 [PATCH 002 of 29] md: Don't acknowlege that stripe-expand is complete until it really is.
 [PATCH 003 of 29] md: Fix error paths if md_probe fails.
 [PATCH 004 of 29] md: linear: correct disk numbering error check
 [PATCH 005 of 29] md: use bio_endio instead of a call to bi_end_io
 [PATCH 006 of 29] md: Improve setting of "events_cleared" for write-intent bitmaps.
 [PATCH 007 of 29] md: Allow setting start point for requested check/repair
 [PATCH 008 of 29] md: Close race in md_probe
 [PATCH 009 of 29] md: Don't try to make md arrays dirty if that is not meaningful.
 [PATCH 010 of 29] md: Enable setting of 'offset' and 'size' of a hot-added spare.
 [PATCH 011 of 29] md: Support adding a spare to a live md array with external metadata.
 [PATCH 012 of 29] md: rationalise return value for ->hot_add_disk method.
 [PATCH 013 of 29] md: Don't reject HOT_REMOVE_DISK request for an array that is not yet started.
 [PATCH 014 of 29] md: Make sure all changes to md/array_state are notified.
 [PATCH 015 of 29] md: Make sure all changes to md/sync_action are notified.
 [PATCH 016 of 29] md: Make sure all changes to md/degraded are notified.
 [PATCH 017 of 29] md: Make sure all changes to md/dev-XX/state are notified
 [PATCH 018 of 29] md: Support changing rdev size on running arrays.
 [PATCH 019 of 29] md: md: kill STRIPE_OP_MOD_DMA in raid5 offload
 [PATCH 020 of 29] md: md: kill STRIPE_OP_IO flag
 [PATCH 021 of 29] md: md: use stripe_head_state in ops_run_io()
 [PATCH 022 of 29] md: md: unify raid5/6 i/o submission
 [PATCH 023 of 29] md: md: replace STRIPE_OP_CHECK with 'check_states'
 [PATCH 024 of 29] md: md: replace STRIPE_OP_BIOFILL with STRIPE_BIOFILL_RUN
 [PATCH 025 of 29] md: md: replace STRIPE_OP_COMPUTE_BLK with STRIPE_COMPUTE_RUN
 [PATCH 026 of 29] md: md: replace STRIPE_OP_{BIODRAIN,PREXOR,POSTXOR} with 'reconstruct_states'
 [PATCH 027 of 29] md: md: replace R5_WantPrexor with R5_WantDrain, add 'prexor' reconstruct_states
 [PATCH 028 of 29] md: md: handle operation chaining in raid5_run_ops
 [PATCH 029 of 29] md: md: rationalize raid5 function names

[PATCH 000 of 29] md: Introduction : patchbomb for 2.6.27 merge window

[NeilBrown]

Following are 29 patches for md suitable for 2.6.27.

The first three are for bugs that can trigger oops or data corruption.
They are possibly suitable for 2.6.26 and for -stable.

There are some bug fixes, some minor feature enhancement (mostly
related to sysfs control of arrays) and some raid5 cleanups

Thanks,
NeilBrown


 [PATCH 001 of 29] md: Ensure interrupted recovery completed properly (v1 metadata plus bitmap)
 [PATCH 002 of 29] md: Don't acknowlege that stripe-expand is complete until it really is.
 [PATCH 003 of 29] md: Fix error paths if md_probe fails.
 [PATCH 004 of 29] md: linear: correct disk numbering error check
 [PATCH 005 of 29] md: use bio_endio instead of a call to bi_end_io
 [PATCH 006 of 29] md: Improve setting of "events_cleared" for write-intent bitmaps.
 [PATCH 007 of 29] md: Allow setting start point for requested check/repair
 [PATCH 008 of 29] md: Close race in md_probe
 [PATCH 009 of 29] md: Don't try to make md arrays dirty if that is not meaningful.
 [PATCH 010 of 29] md: Enable setting of 'offset' and 'size' of a hot-added spare.
 [PATCH 011 of 29] md: Support adding a spare to a live md array with external metadata.
 [PATCH 012 of 29] md: rationalise return value for ->hot_add_disk method.
 [PATCH 013 of 29] md: Don't reject HOT_REMOVE_DISK request for an array that is not yet started.
 [PATCH 014 of 29] md: Make sure all changes to md/array_state are notified.
 [PATCH 015 of 29] md: Make sure all changes to md/sync_action are notified.
 [PATCH 016 of 29] md: Make sure all changes to md/degraded are notified.
 [PATCH 017 of 29] md: Make sure all changes to md/dev-XX/state are notified
 [PATCH 018 of 29] md: Support changing rdev size on running arrays.
 [PATCH 019 of 29] md: md: kill STRIPE_OP_MOD_DMA in raid5 offload
 [PATCH 020 of 29] md: md: kill STRIPE_OP_IO flag
 [PATCH 021 of 29] md: md: use stripe_head_state in ops_run_io()
 [PATCH 022 of 29] md: md: unify raid5/6 i/o submission
 [PATCH 023 of 29] md: md: replace STRIPE_OP_CHECK with 'check_states'
 [PATCH 024 of 29] md: md: replace STRIPE_OP_BIOFILL with STRIPE_BIOFILL_RUN
 [PATCH 025 of 29] md: md: replace STRIPE_OP_COMPUTE_BLK with STRIPE_COMPUTE_RUN
 [PATCH 026 of 29] md: md: replace STRIPE_OP_{BIODRAIN,PREXOR,POSTXOR} with 'reconstruct_states'
 [PATCH 027 of 29] md: md: replace R5_WantPrexor with R5_WantDrain, add 'prexor' reconstruct_states
 [PATCH 028 of 29] md: md: handle operation chaining in raid5_run_ops
 [PATCH 029 of 29] md: md: rationalize raid5 function names

[PATCH 001 of 29] md: Ensure interrupted recovery completed properly (v1 metadata plus bitmap)

[NeilBrown]

If, while assembling an array, we find a device which is not fully
in-sync with the array, it is important to set the "fullsync" flags.
This is an exact analog to the setting of this flag in hot_add_disk
methods.

Currently, only v1.x metadata supports having devices in an array
which are not fully in-sync (it keep track of how in sync they are).
The 'fullsync' flag only makes a difference when a write-intent bitmap
is being used.  In this case it tells recovery to ignore the bitmap
and recovery all blocks.

This fix is already in place for raid1, but not raid5/6 or raid10.

So without this fix, a raid1 ir raid4/5/6 array with version 1.x
metadata and a write intent bitmaps, that is stopped in the middle
of a recovery, will appear to complete the recovery instantly
after it is reassembled, but the recovery will not be correct.

If you might have an array like that, issueing
   echo repair > /sys/block/mdXX/md/sync_action

will make sure recovery completes properly.

Cc: <stable@kernel.org>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid10.c |    2 ++
 ./drivers/md/raid5.c  |    4 +++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff .prev/drivers/md/raid10.c ./drivers/md/raid10.c
--- .prev/drivers/md/raid10.c	2008-06-27 15:14:05.000000000 +1000
+++ ./drivers/md/raid10.c	2008-06-27 15:19:36.000000000 +1000
@@ -2137,6 +2137,8 @@ static int run(mddev_t *mddev)
 		    !test_bit(In_sync, &disk->rdev->flags)) {
 			disk->head_position = 0;
 			mddev->degraded++;
+			if (disk->rdev)
+				conf->fullsync = 1;
 		}
 	}
 

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 15:14:05.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 15:19:36.000000000 +1000
@@ -4305,7 +4305,9 @@ static int run(mddev_t *mddev)
 				" disk %d\n", bdevname(rdev->bdev,b),
 				raid_disk);
 			working_disks++;
-		}
+		} else
+			/* Cannot rely on bitmap to complete recovery */
+			conf->fullsync = 1;
 	}
 
 	/*

[PATCH 001 of 29] md: Ensure interrupted recovery completed properly (v1 metadata plus bitmap)

[NeilBrown]

If, while assembling an array, we find a device which is not fully
in-sync with the array, it is important to set the "fullsync" flags.
This is an exact analog to the setting of this flag in hot_add_disk
methods.

Currently, only v1.x metadata supports having devices in an array
which are not fully in-sync (it keep track of how in sync they are).
The 'fullsync' flag only makes a difference when a write-intent bitmap
is being used.  In this case it tells recovery to ignore the bitmap
and recovery all blocks.

This fix is already in place for raid1, but not raid5/6 or raid10.

So without this fix, a raid1 ir raid4/5/6 array with version 1.x
metadata and a write intent bitmaps, that is stopped in the middle
of a recovery, will appear to complete the recovery instantly
after it is reassembled, but the recovery will not be correct.

If you might have an array like that, issueing
   echo repair > /sys/block/mdXX/md/sync_action

will make sure recovery completes properly.

Cc: <stable@kernel.org>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid10.c |    2 ++
 ./drivers/md/raid5.c  |    4 +++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff .prev/drivers/md/raid10.c ./drivers/md/raid10.c
--- .prev/drivers/md/raid10.c	2008-06-27 15:14:05.000000000 +1000
+++ ./drivers/md/raid10.c	2008-06-27 15:19:36.000000000 +1000
@@ -2137,6 +2137,8 @@ static int run(mddev_t *mddev)
 		    !test_bit(In_sync, &disk->rdev->flags)) {
 			disk->head_position = 0;
 			mddev->degraded++;
+			if (disk->rdev)
+				conf->fullsync = 1;
 		}
 	}
 

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 15:14:05.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 15:19:36.000000000 +1000
@@ -4305,7 +4305,9 @@ static int run(mddev_t *mddev)
 				" disk %d\n", bdevname(rdev->bdev,b),
 				raid_disk);
 			working_disks++;
-		}
+		} else
+			/* Cannot rely on bitmap to complete recovery */
+			conf->fullsync = 1;
 	}
 
 	/*

[PATCH 002 of 29] md: Don't acknowlege that stripe-expand is complete until it really is.

[NeilBrown]

We shouldn't acknowledge that a stripe has been expanded (When
reshaping a raid5 by adding a device) until the moved data has
actually been written out.  However we are currently
acknowledging (by calling md_done_sync) when the POST_XOR
is complete and before the write.

So track in s.locked whether there are pending writes, and don't
call md_done_sync yet if there are.

Note: we all set R5_LOCKED on devices which are are about to
read from.  This probably isn't technically necessary, but is
usually done when writing a block, and justifies the use of
s.locked here.

This bug can lead to a crash if an array is stopped while an reshape
is in progress.

Cc: <stable@kernel.org>
Signed-off-by: Neil Brown <neilb@suse.de>



### Diffstat output
 ./drivers/md/raid5.c |    3 +++
 1 file changed, 3 insertions(+)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 15:30:19.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 15:22:48.000000000 +1000
@@ -2898,6 +2898,8 @@ static void handle_stripe5(struct stripe
 
 		for (i = conf->raid_disks; i--; ) {
 			set_bit(R5_Wantwrite, &sh->dev[i].flags);
+			set_bit(R5_LOCKED, &dev->flags);
+			s.locked++;
 			if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
 				sh->ops.count++;
 		}
@@ -2911,6 +2913,7 @@ static void handle_stripe5(struct stripe
 			conf->raid_disks);
 		s.locked += handle_write_operations5(sh, 1, 1);
 	} else if (s.expanded &&
+		   s.locked == 0 &&
 		!test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
 		clear_bit(STRIPE_EXPAND_READY, &sh->state);
 		atomic_dec(&conf->reshape_stripes);

[PATCH 002 of 29] md: Don't acknowlege that stripe-expand is complete until it really is.

[NeilBrown]

We shouldn't acknowledge that a stripe has been expanded (When
reshaping a raid5 by adding a device) until the moved data has
actually been written out.  However we are currently
acknowledging (by calling md_done_sync) when the POST_XOR
is complete and before the write.

So track in s.locked whether there are pending writes, and don't
call md_done_sync yet if there are.

Note: we all set R5_LOCKED on devices which are are about to
read from.  This probably isn't technically necessary, but is
usually done when writing a block, and justifies the use of
s.locked here.

This bug can lead to a crash if an array is stopped while an reshape
is in progress.

Cc: <stable@kernel.org>
Signed-off-by: Neil Brown <neilb@suse.de>



### Diffstat output
 ./drivers/md/raid5.c |    3 +++
 1 file changed, 3 insertions(+)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 15:30:19.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 15:22:48.000000000 +1000
@@ -2898,6 +2898,8 @@ static void handle_stripe5(struct stripe
 
 		for (i = conf->raid_disks; i--; ) {
 			set_bit(R5_Wantwrite, &sh->dev[i].flags);
+			set_bit(R5_LOCKED, &dev->flags);
+			s.locked++;
 			if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
 				sh->ops.count++;
 		}
@@ -2911,6 +2913,7 @@ static void handle_stripe5(struct stripe
 			conf->raid_disks);
 		s.locked += handle_write_operations5(sh, 1, 1);
 	} else if (s.expanded &&
+		   s.locked == 0 &&
 		!test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
 		clear_bit(STRIPE_EXPAND_READY, &sh->state);
 		atomic_dec(&conf->reshape_stripes);

[PATCH 003 of 29] md: Fix error paths if md_probe fails.

[NeilBrown]

md_probe can fail (e.g. alloc_disk could fail) without
returning an error (as it alway returns NULL).
So when we call mddev_find immediately afterwards, we need
to check that md_probe actually succeeded.  This means checking
that mdev->gendisk is non-NULL.

cc: <stable@kernel.org>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/md.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff .prev/drivers/md/md.c ./drivers/md/md.c
--- .prev/drivers/md/md.c	2008-06-27 15:14:04.000000000 +1000
+++ ./drivers/md/md.c	2008-06-27 15:31:08.000000000 +1000
@@ -3897,8 +3897,10 @@ static void autorun_devices(int part)
 
 		md_probe(dev, NULL, NULL);
 		mddev = mddev_find(dev);
-		if (!mddev) {
-			printk(KERN_ERR 
+		if (!mddev || !mddev->gendisk) {
+			if (mddev)
+				mddev_put(mddev);
+			printk(KERN_ERR
 				"md: cannot allocate memory for md drive.\n");
 			break;
 		}

[PATCH 003 of 29] md: Fix error paths if md_probe fails.

[NeilBrown]

md_probe can fail (e.g. alloc_disk could fail) without
returning an error (as it alway returns NULL).
So when we call mddev_find immediately afterwards, we need
to check that md_probe actually succeeded.  This means checking
that mdev->gendisk is non-NULL.

cc: <stable@kernel.org>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/md.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff .prev/drivers/md/md.c ./drivers/md/md.c
--- .prev/drivers/md/md.c	2008-06-27 15:14:04.000000000 +1000
+++ ./drivers/md/md.c	2008-06-27 15:31:08.000000000 +1000
@@ -3897,8 +3897,10 @@ static void autorun_devices(int part)
 
 		md_probe(dev, NULL, NULL);
 		mddev = mddev_find(dev);
-		if (!mddev) {
-			printk(KERN_ERR 
+		if (!mddev || !mddev->gendisk) {
+			if (mddev)
+				mddev_put(mddev);
+			printk(KERN_ERR
 				"md: cannot allocate memory for md drive.\n");
 			break;
 		}

[PATCH 004 of 29] md: linear: correct disk numbering error check

[NeilBrown]

From: "Nikanth Karthikesan" <knikanth@novell.com>

Correct disk numbering problem check.

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/linear.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff .prev/drivers/md/linear.c ./drivers/md/linear.c
--- .prev/drivers/md/linear.c	2008-06-27 15:19:55.000000000 +1000
+++ ./drivers/md/linear.c	2008-06-27 15:31:20.000000000 +1000
@@ -126,7 +126,7 @@ static linear_conf_t *linear_conf(mddev_
 		int j = rdev->raid_disk;
 		dev_info_t *disk = conf->disks + j;
 
-		if (j < 0 || j > raid_disks || disk->rdev) {
+		if (j < 0 || j >= raid_disks || disk->rdev) {
 			printk("linear: disk numbering problem. Aborting!\n");
 			goto out;
 		}

[PATCH 004 of 29] md: linear: correct disk numbering error check

[NeilBrown]

From: "Nikanth Karthikesan" <knikanth@novell.com>

Correct disk numbering problem check.

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/linear.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff .prev/drivers/md/linear.c ./drivers/md/linear.c
--- .prev/drivers/md/linear.c	2008-06-27 15:19:55.000000000 +1000
+++ ./drivers/md/linear.c	2008-06-27 15:31:20.000000000 +1000
@@ -126,7 +126,7 @@ static linear_conf_t *linear_conf(mddev_
 		int j = rdev->raid_disk;
 		dev_info_t *disk = conf->disks + j;
 
-		if (j < 0 || j > raid_disks || disk->rdev) {
+		if (j < 0 || j >= raid_disks || disk->rdev) {
 			printk("linear: disk numbering problem. Aborting!\n");
 			goto out;
 		}

[PATCH 005 of 29] md: use bio_endio instead of a call to bi_end_io

[NeilBrown]

Turn calls to bi->bi_end_io() into bio_endio(). Apparently bio_endio does
exactly the same error processing as is hardcoded at these places.

bio_endio() avoids recursion (or will soon), so it should be used.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c |   16 ++++------------
 1 file changed, 4 insertions(+), 12 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 15:22:48.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 15:31:23.000000000 +1000
@@ -115,9 +115,7 @@ static void return_io(struct bio *return
 		return_bi = bi->bi_next;
 		bi->bi_next = NULL;
 		bi->bi_size = 0;
-		bi->bi_end_io(bi,
-			      test_bit(BIO_UPTODATE, &bi->bi_flags)
-			        ? 0 : -EIO);
+		bio_endio(bi, 0);
 		bi = return_bi;
 	}
 }
@@ -3700,9 +3698,7 @@ static int make_request(struct request_q
 		if ( rw == WRITE )
 			md_write_end(mddev);
 
-		bi->bi_end_io(bi,
-			      test_bit(BIO_UPTODATE, &bi->bi_flags)
-			        ? 0 : -EIO);
+		bio_endio(bi, 0);
 	}
 	return 0;
 }
@@ -4005,12 +4001,8 @@ static int  retry_aligned_read(raid5_con
 	spin_lock_irq(&conf->device_lock);
 	remaining = --raid_bio->bi_phys_segments;
 	spin_unlock_irq(&conf->device_lock);
-	if (remaining == 0) {
-
-		raid_bio->bi_end_io(raid_bio,
-			      test_bit(BIO_UPTODATE, &raid_bio->bi_flags)
-			        ? 0 : -EIO);
-	}
+	if (remaining == 0)
+		bio_endio(raid_bio, 0);
 	if (atomic_dec_and_test(&conf->active_aligned_reads))
 		wake_up(&conf->wait_for_stripe);
 	return handled;

[PATCH 005 of 29] md: use bio_endio instead of a call to bi_end_io

[NeilBrown]

Turn calls to bi->bi_end_io() into bio_endio(). Apparently bio_endio does
exactly the same error processing as is hardcoded at these places.

bio_endio() avoids recursion (or will soon), so it should be used.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c |   16 ++++------------
 1 file changed, 4 insertions(+), 12 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 15:22:48.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 15:31:23.000000000 +1000
@@ -115,9 +115,7 @@ static void return_io(struct bio *return
 		return_bi = bi->bi_next;
 		bi->bi_next = NULL;
 		bi->bi_size = 0;
-		bi->bi_end_io(bi,
-			      test_bit(BIO_UPTODATE, &bi->bi_flags)
-			        ? 0 : -EIO);
+		bio_endio(bi, 0);
 		bi = return_bi;
 	}
 }
@@ -3700,9 +3698,7 @@ static int make_request(struct request_q
 		if ( rw == WRITE )
 			md_write_end(mddev);
 
-		bi->bi_end_io(bi,
-			      test_bit(BIO_UPTODATE, &bi->bi_flags)
-			        ? 0 : -EIO);
+		bio_endio(bi, 0);
 	}
 	return 0;
 }
@@ -4005,12 +4001,8 @@ static int  retry_aligned_read(raid5_con
 	spin_lock_irq(&conf->device_lock);
 	remaining = --raid_bio->bi_phys_segments;
 	spin_unlock_irq(&conf->device_lock);
-	if (remaining == 0) {
-
-		raid_bio->bi_end_io(raid_bio,
-			      test_bit(BIO_UPTODATE, &raid_bio->bi_flags)
-			        ? 0 : -EIO);
-	}
+	if (remaining == 0)
+		bio_endio(raid_bio, 0);
 	if (atomic_dec_and_test(&conf->active_aligned_reads))
 		wake_up(&conf->wait_for_stripe);
 	return handled;

[PATCH 006 of 29] md: Improve setting of "events_cleared" for write-intent bitmaps.

[NeilBrown]

When an array is degraded, bits in the write-intent bitmap are not
cleared, so that if the missing device is re-added, it can be synced
by only updated those parts of the device that have changed since
it was removed.

The enable this a 'events_cleared' value is stored. It is the event
counter for the array the last time that any bits were cleared.

Sometimes - if a device disappears from an array while it is 'clean' -
the events_cleared value gets updated incorrectly (there are subtle
ordering issues between updateing events in the main metadata and the
bitmap metadata) resulting in the missing device appearing to require
a full resync when it is re-added.

With this patch, we update events_cleared precisely when we are about
to clear a bit in the bitmap.  We record events_cleared when we clear
the bit internally, and copy that to the superblock which is written
out before the bit on storage.  This makes it more "obviously correct".

We also need to update events_cleared when the event_count is going
backwards (as happens on a dirty->clean transition of a non-degraded
array).

Thanks to Mike Snitzer for identifying this problem and testing early
"fixes".


Cc:  "Mike Snitzer" <snitzer@gmail.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/bitmap.c         |   29 ++++++++++++++++++++++++-----
 ./include/linux/raid/bitmap.h |    1 +
 2 files changed, 25 insertions(+), 5 deletions(-)

diff .prev/drivers/md/bitmap.c ./drivers/md/bitmap.c
--- .prev/drivers/md/bitmap.c	2008-06-27 15:14:04.000000000 +1000
+++ ./drivers/md/bitmap.c	2008-06-27 15:31:25.000000000 +1000
@@ -454,8 +454,11 @@ void bitmap_update_sb(struct bitmap *bit
 	spin_unlock_irqrestore(&bitmap->lock, flags);
 	sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 	sb->events = cpu_to_le64(bitmap->mddev->events);
-	if (!bitmap->mddev->degraded)
-		sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
+	if (bitmap->mddev->events < bitmap->events_cleared) {
+		/* rocking back to read-only */
+		bitmap->events_cleared = bitmap->mddev->events;
+		sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
+	}
 	kunmap_atomic(sb, KM_USER0);
 	write_page(bitmap, bitmap->sb_page, 1);
 }
@@ -1085,9 +1088,19 @@ void bitmap_daemon_work(struct bitmap *b
 			} else
 				spin_unlock_irqrestore(&bitmap->lock, flags);
 			lastpage = page;
-/*
-			printk("bitmap clean at page %lu\n", j);
-*/
+
+			/* We are possibly going to clear some bits, so make
+			 * sure that events_cleared is up-to-date.
+			 */
+			if (bitmap->need_sync) {
+				bitmap_super_t *sb;
+				bitmap->need_sync = 0;
+				sb = kmap_atomic(bitmap->sb_page, KM_USER0);
+				sb->events_cleared =
+					cpu_to_le64(bitmap->events_cleared);
+				kunmap_atomic(sb, KM_USER0);
+				write_page(bitmap, bitmap->sb_page, 1);
+			}
 			spin_lock_irqsave(&bitmap->lock, flags);
 			clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
 		}
@@ -1257,6 +1270,12 @@ void bitmap_endwrite(struct bitmap *bitm
 			return;
 		}
 
+		if (success &&
+		    bitmap->events_cleared < bitmap->mddev->events) {
+			bitmap->events_cleared = bitmap->mddev->events;
+			bitmap->need_sync = 1;
+		}
+
 		if (!success && ! (*bmc & NEEDED_MASK))
 			*bmc |= NEEDED_MASK;
 

diff .prev/include/linux/raid/bitmap.h ./include/linux/raid/bitmap.h
--- .prev/include/linux/raid/bitmap.h	2008-06-27 15:14:04.000000000 +1000
+++ ./include/linux/raid/bitmap.h	2008-06-27 15:31:25.000000000 +1000
@@ -221,6 +221,7 @@ struct bitmap {
 	unsigned long syncchunk;
 
 	__u64	events_cleared;
+	int need_sync;
 
 	/* bitmap spinlock */
 	spinlock_t lock;

[PATCH 006 of 29] md: Improve setting of "events_cleared" for write-intent bitmaps.

[NeilBrown]

When an array is degraded, bits in the write-intent bitmap are not
cleared, so that if the missing device is re-added, it can be synced
by only updated those parts of the device that have changed since
it was removed.

The enable this a 'events_cleared' value is stored. It is the event
counter for the array the last time that any bits were cleared.

Sometimes - if a device disappears from an array while it is 'clean' -
the events_cleared value gets updated incorrectly (there are subtle
ordering issues between updateing events in the main metadata and the
bitmap metadata) resulting in the missing device appearing to require
a full resync when it is re-added.

With this patch, we update events_cleared precisely when we are about
to clear a bit in the bitmap.  We record events_cleared when we clear
the bit internally, and copy that to the superblock which is written
out before the bit on storage.  This makes it more "obviously correct".

We also need to update events_cleared when the event_count is going
backwards (as happens on a dirty->clean transition of a non-degraded
array).

Thanks to Mike Snitzer for identifying this problem and testing early
"fixes".


Cc:  "Mike Snitzer" <snitzer@gmail.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/bitmap.c         |   29 ++++++++++++++++++++++++-----
 ./include/linux/raid/bitmap.h |    1 +
 2 files changed, 25 insertions(+), 5 deletions(-)

diff .prev/drivers/md/bitmap.c ./drivers/md/bitmap.c
--- .prev/drivers/md/bitmap.c	2008-06-27 15:14:04.000000000 +1000
+++ ./drivers/md/bitmap.c	2008-06-27 15:31:25.000000000 +1000
@@ -454,8 +454,11 @@ void bitmap_update_sb(struct bitmap *bit
 	spin_unlock_irqrestore(&bitmap->lock, flags);
 	sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
 	sb->events = cpu_to_le64(bitmap->mddev->events);
-	if (!bitmap->mddev->degraded)
-		sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
+	if (bitmap->mddev->events < bitmap->events_cleared) {
+		/* rocking back to read-only */
+		bitmap->events_cleared = bitmap->mddev->events;
+		sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
+	}
 	kunmap_atomic(sb, KM_USER0);
 	write_page(bitmap, bitmap->sb_page, 1);
 }
@@ -1085,9 +1088,19 @@ void bitmap_daemon_work(struct bitmap *b
 			} else
 				spin_unlock_irqrestore(&bitmap->lock, flags);
 			lastpage = page;
-/*
-			printk("bitmap clean at page %lu\n", j);
-*/
+
+			/* We are possibly going to clear some bits, so make
+			 * sure that events_cleared is up-to-date.
+			 */
+			if (bitmap->need_sync) {
+				bitmap_super_t *sb;
+				bitmap->need_sync = 0;
+				sb = kmap_atomic(bitmap->sb_page, KM_USER0);
+				sb->events_cleared =
+					cpu_to_le64(bitmap->events_cleared);
+				kunmap_atomic(sb, KM_USER0);
+				write_page(bitmap, bitmap->sb_page, 1);
+			}
 			spin_lock_irqsave(&bitmap->lock, flags);
 			clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
 		}
@@ -1257,6 +1270,12 @@ void bitmap_endwrite(struct bitmap *bitm
 			return;
 		}
 
+		if (success &&
+		    bitmap->events_cleared < bitmap->mddev->events) {
+			bitmap->events_cleared = bitmap->mddev->events;
+			bitmap->need_sync = 1;
+		}
+
 		if (!success && ! (*bmc & NEEDED_MASK))
 			*bmc |= NEEDED_MASK;
 

diff .prev/include/linux/raid/bitmap.h ./include/linux/raid/bitmap.h
--- .prev/include/linux/raid/bitmap.h	2008-06-27 15:14:04.000000000 +1000
+++ ./include/linux/raid/bitmap.h	2008-06-27 15:31:25.000000000 +1000
@@ -221,6 +221,7 @@ struct bitmap {
 	unsigned long syncchunk;
 
 	__u64	events_cleared;
+	int need_sync;
 
 	/* bitmap spinlock */
 	spinlock_t lock;

[PATCH 007 of 29] md: Allow setting start point for requested check/repair

[NeilBrown]

This makes it possible to just resync a small part of an array.
e.g. if a drive reports that it has questionable sectors,
a 'repair' of just the region covering those sectors will 
cause them to be read and, if there is an error, re-written
with correct data.


Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/md.c           |   47 +++++++++++++++++++++++++++++++++++++++-----
 ./include/linux/raid/md_k.h |    2 +
 2 files changed, 44 insertions(+), 5 deletions(-)

diff .prev/drivers/md/md.c ./drivers/md/md.c
--- .prev/drivers/md/md.c	2008-06-27 15:31:08.000000000 +1000
+++ ./drivers/md/md.c	2008-06-27 15:31:27.000000000 +1000
@@ -278,6 +278,7 @@ static mddev_t * mddev_find(dev_t unit)
 	init_waitqueue_head(&new->sb_wait);
 	init_waitqueue_head(&new->recovery_wait);
 	new->reshape_position = MaxSector;
+	new->resync_min = 0;
 	new->resync_max = MaxSector;
 	new->level = LEVEL_NONE;
 
@@ -3075,6 +3076,36 @@ sync_completed_show(mddev_t *mddev, char
 static struct md_sysfs_entry md_sync_completed = __ATTR_RO(sync_completed);
 
 static ssize_t
+min_sync_show(mddev_t *mddev, char *page)
+{
+	return sprintf(page, "%llu\n",
+		       (unsigned long long)mddev->resync_min);
+}
+static ssize_t
+min_sync_store(mddev_t *mddev, const char *buf, size_t len)
+{
+	unsigned long long min;
+	if (strict_strtoull(buf, 10, &min))
+		return -EINVAL;
+	if (min > mddev->resync_max)
+		return -EINVAL;
+	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
+		return -EBUSY;
+
+	/* Must be a multiple of chunk_size */
+	if (mddev->chunk_size) {
+		if (min & (sector_t)((mddev->chunk_size>>9)-1))
+			return -EINVAL;
+	}
+	mddev->resync_min = min;
+
+	return len;
+}
+
+static struct md_sysfs_entry md_min_sync =
+__ATTR(sync_min, S_IRUGO|S_IWUSR, min_sync_show, min_sync_store);
+
+static ssize_t
 max_sync_show(mddev_t *mddev, char *page)
 {
 	if (mddev->resync_max == MaxSector)
@@ -3089,9 +3120,10 @@ max_sync_store(mddev_t *mddev, const cha
 	if (strncmp(buf, "max", 3) == 0)
 		mddev->resync_max = MaxSector;
 	else {
-		char *ep;
-		unsigned long long max = simple_strtoull(buf, &ep, 10);
-		if (ep == buf || (*ep != 0 && *ep != '\n'))
+		unsigned long long max;
+		if (strict_strtoull(buf, 10, &max))
+			return -EINVAL;
+		if (max < mddev->resync_min)
 			return -EINVAL;
 		if (max < mddev->resync_max &&
 		    test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
@@ -3222,6 +3254,7 @@ static struct attribute *md_redundancy_a
 	&md_sync_speed.attr,
 	&md_sync_force_parallel.attr,
 	&md_sync_completed.attr,
+	&md_min_sync.attr,
 	&md_max_sync.attr,
 	&md_suspend_lo.attr,
 	&md_suspend_hi.attr,
@@ -3777,6 +3810,7 @@ static int do_md_stop(mddev_t * mddev, i
 		mddev->size = 0;
 		mddev->raid_disks = 0;
 		mddev->recovery_cp = 0;
+		mddev->resync_min = 0;
 		mddev->resync_max = MaxSector;
 		mddev->reshape_position = MaxSector;
 		mddev->external = 0;
@@ -5625,9 +5659,11 @@ void md_do_sync(mddev_t *mddev)
 		max_sectors = mddev->resync_max_sectors;
 		mddev->resync_mismatches = 0;
 		/* we don't use the checkpoint if there's a bitmap */
-		if (!mddev->bitmap &&
-		    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
+		if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
+			j = mddev->resync_min;
+		else if (!mddev->bitmap)
 			j = mddev->recovery_cp;
+
 	} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
 		max_sectors = mddev->size << 1;
 	else {
@@ -5796,6 +5832,7 @@ void md_do_sync(mddev_t *mddev)
 
  skip:
 	mddev->curr_resync = 0;
+	mddev->resync_min = 0;
 	mddev->resync_max = MaxSector;
 	sysfs_notify(&mddev->kobj, NULL, "sync_completed");
 	wake_up(&resync_wait);

diff .prev/include/linux/raid/md_k.h ./include/linux/raid/md_k.h
--- .prev/include/linux/raid/md_k.h	2008-06-27 15:14:04.000000000 +1000
+++ ./include/linux/raid/md_k.h	2008-06-27 15:31:27.000000000 +1000
@@ -227,6 +227,8 @@ struct mddev_s
 	atomic_t			recovery_active; /* blocks scheduled, but not written */
 	wait_queue_head_t		recovery_wait;
 	sector_t			recovery_cp;
+	sector_t			resync_min;	/* user requested sync
+							 * starts here */
 	sector_t			resync_max;	/* resync should pause
 							 * when it gets here */
 

[PATCH 008 of 29] md: Close race in md_probe

[NeilBrown]

There is a possible race in md_probe.  If two threads call md_probe
for the same device, then one could exit (having checked that
->gendisk exists) before the other has called kobject_init_and_add,
thus returning an incomplete kobj which will cause problems when
we try to add children to it.

So extend the range of protection of disks_mutex slightly to
avoid this possibility.

Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/md.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff .prev/drivers/md/md.c ./drivers/md/md.c
--- .prev/drivers/md/md.c	2008-06-27 15:31:27.000000000 +1000
+++ ./drivers/md/md.c	2008-06-27 15:31:35.000000000 +1000
@@ -3359,9 +3359,9 @@ static struct kobject *md_probe(dev_t de
 	disk->queue = mddev->queue;
 	add_disk(disk);
 	mddev->gendisk = disk;
-	mutex_unlock(&disks_mutex);
 	error = kobject_init_and_add(&mddev->kobj, &md_ktype, &disk->dev.kobj,
 				     "%s", "md");
+	mutex_unlock(&disks_mutex);
 	if (error)
 		printk(KERN_WARNING "md: cannot register %s/md - name in use\n",
 		       disk->disk_name);

[PATCH 009 of 29] md: Don't try to make md arrays dirty if that is not meaningful.

[NeilBrown]

Arrays personalities such as 'raid0' and 'linear' have no redundancy,
and so marking them as 'clean' or 'dirty' is not meaningful.
So always allow write requests without requiring a superblock update.

Such arrays types are detected by ->sync_request being NULL.  If it is
not possible to send a sync request we don't need a 'dirty' flag because
all a dirty flag does is trigger some sync_requests.

Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/md.c |    2 ++
 1 file changed, 2 insertions(+)

diff .prev/drivers/md/md.c ./drivers/md/md.c
--- .prev/drivers/md/md.c	2008-06-27 15:31:35.000000000 +1000
+++ ./drivers/md/md.c	2008-06-27 15:33:00.000000000 +1000
@@ -5536,6 +5536,8 @@ void md_allow_write(mddev_t *mddev)
 		return;
 	if (mddev->ro)
 		return;
+	if (!mddev->pers->sync_request)
+		return;
 
 	spin_lock_irq(&mddev->write_lock);
 	if (mddev->in_sync) {

[PATCH 010 of 29] md: Enable setting of 'offset' and 'size' of a hot-added spare.

[NeilBrown]

offset_store and rdev_size_store allow control of the region of a
device which is to be using in an md/raid array.
They only allow these values to be set when an array is being assembled,
as changing them on an active array could be dangerous.
However when adding a spare device to an array, we might need to
set the offset and size before starting recovery.  So allow
these values to be set also if "->raid_disk < 0" which indicates that
the device is still a spare.

Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/md.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff .prev/drivers/md/md.c ./drivers/md/md.c
--- .prev/drivers/md/md.c	2008-06-27 15:33:00.000000000 +1000
+++ ./drivers/md/md.c	2008-06-27 15:33:01.000000000 +1000
@@ -1984,7 +1984,7 @@ offset_store(mdk_rdev_t *rdev, const cha
 	unsigned long long offset = simple_strtoull(buf, &e, 10);
 	if (e==buf || (*e && *e != '\n'))
 		return -EINVAL;
-	if (rdev->mddev->pers)
+	if (rdev->mddev->pers && rdev->raid_disk >= 0)
 		return -EBUSY;
 	if (rdev->size && rdev->mddev->external)
 		/* Must set offset before size, so overlap checks
@@ -2023,7 +2023,7 @@ rdev_size_store(mdk_rdev_t *rdev, const 
 
 	if (e==buf || (*e && *e != '\n'))
 		return -EINVAL;
-	if (my_mddev->pers)
+	if (my_mddev->pers && rdev->raid_disk >= 0)
 		return -EBUSY;
 	rdev->size = size;
 	if (size > oldsize && rdev->mddev->external) {

[PATCH 011 of 29] md: Support adding a spare to a live md array with external metadata.

[NeilBrown]

i.e. extend the 'md/dev-XXX/slot' attribute so that you can
tell a device to fill an vacant slot in an and md array.


Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/md.c        |   42 +++++++++++++++++++++++++++++++++++++++---
 ./drivers/md/multipath.c |    7 ++++++-
 ./drivers/md/raid1.c     |    7 ++++++-
 ./drivers/md/raid10.c    |   10 ++++++++--
 ./drivers/md/raid5.c     |   10 ++++++++--
 5 files changed, 67 insertions(+), 9 deletions(-)

diff .prev/drivers/md/md.c ./drivers/md/md.c
--- .prev/drivers/md/md.c	2008-06-27 15:33:01.000000000 +1000
+++ ./drivers/md/md.c	2008-06-27 15:33:01.000000000 +1000
@@ -1932,7 +1932,7 @@ slot_store(mdk_rdev_t *rdev, const char 
 		slot = -1;
 	else if (e==buf || (*e && *e!= '\n'))
 		return -EINVAL;
-	if (rdev->mddev->pers) {
+	if (rdev->mddev->pers && slot == -1) {
 		/* Setting 'slot' on an active array requires also
 		 * updating the 'rd%d' link, and communicating
 		 * with the personality with ->hot_*_disk.
@@ -1940,8 +1940,6 @@ slot_store(mdk_rdev_t *rdev, const char 
 		 * failed/spare devices.  This normally happens automatically,
 		 * but not when the metadata is externally managed.
 		 */
-		if (slot != -1)
-			return -EBUSY;
 		if (rdev->raid_disk == -1)
 			return -EEXIST;
 		/* personality does all needed checks */
@@ -1955,6 +1953,44 @@ slot_store(mdk_rdev_t *rdev, const char 
 		sysfs_remove_link(&rdev->mddev->kobj, nm);
 		set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
 		md_wakeup_thread(rdev->mddev->thread);
+	} else if (rdev->mddev->pers) {
+		mdk_rdev_t *rdev2;
+		struct list_head *tmp;
+		/* Activating a spare .. or possibly reactivating
+		 * if we every get bitmaps working here.
+		 */
+
+		if (rdev->raid_disk != -1)
+			return -EBUSY;
+
+		if (rdev->mddev->pers->hot_add_disk == NULL)
+			return -EINVAL;
+
+		rdev_for_each(rdev2, tmp, rdev->mddev)
+			if (rdev2->raid_disk == slot)
+				return -EEXIST;
+
+		rdev->raid_disk = slot;
+		if (test_bit(In_sync, &rdev->flags))
+			rdev->saved_raid_disk = slot;
+		else
+			rdev->saved_raid_disk = -1;
+		err = rdev->mddev->pers->
+			hot_add_disk(rdev->mddev, rdev);
+		if (err != 1) {
+			rdev->raid_disk = -1;
+			if (err == 0)
+				return -EEXIST;
+			return err;
+		}
+		sprintf(nm, "rd%d", rdev->raid_disk);
+		if (sysfs_create_link(&rdev->mddev->kobj, &rdev->kobj, nm))
+			printk(KERN_WARNING
+			       "md: cannot register "
+			       "%s for %s\n",
+			       nm, mdname(rdev->mddev));
+
+		/* don't wakeup anyone, leave that to userspace. */
 	} else {
 		if (slot >= rdev->mddev->raid_disks)
 			return -ENOSPC;

diff .prev/drivers/md/multipath.c ./drivers/md/multipath.c
--- .prev/drivers/md/multipath.c	2008-06-27 15:14:03.000000000 +1000
+++ ./drivers/md/multipath.c	2008-06-27 15:33:01.000000000 +1000
@@ -284,10 +284,15 @@ static int multipath_add_disk(mddev_t *m
 	int found = 0;
 	int path;
 	struct multipath_info *p;
+	int first = 0;
+	int last = mddev->raid_disks - 1;
+
+	if (rdev->raid_disk >= 0)
+		first = last = rdev->raid_disk;
 
 	print_multipath_conf(conf);
 
-	for (path=0; path<mddev->raid_disks; path++) 
+	for (path = first; path <= last; path++)
 		if ((p=conf->multipaths+path)->rdev == NULL) {
 			q = rdev->bdev->bd_disk->queue;
 			blk_queue_stack_limits(mddev->queue, q);

diff .prev/drivers/md/raid10.c ./drivers/md/raid10.c
--- .prev/drivers/md/raid10.c	2008-06-27 15:19:36.000000000 +1000
+++ ./drivers/md/raid10.c	2008-06-27 15:33:01.000000000 +1000
@@ -1116,6 +1116,8 @@ static int raid10_add_disk(mddev_t *mdde
 	int found = 0;
 	int mirror;
 	mirror_info_t *p;
+	int first = 0;
+	int last = mddev->raid_disks - 1;
 
 	if (mddev->recovery_cp < MaxSector)
 		/* only hot-add to in-sync arrays, as recovery is
@@ -1125,12 +1127,16 @@ static int raid10_add_disk(mddev_t *mdde
 	if (!enough(conf))
 		return 0;
 
+	if (rdev->raid_disk)
+		first = last = rdev->raid_disk;
+
 	if (rdev->saved_raid_disk >= 0 &&
+	    rdev->saved_raid_disk >= first &&
 	    conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
 		mirror = rdev->saved_raid_disk;
 	else
-		mirror = 0;
-	for ( ; mirror < mddev->raid_disks; mirror++)
+		mirror = first;
+	for ( ; mirror <= last ; mirror++)
 		if ( !(p=conf->mirrors+mirror)->rdev) {
 
 			blk_queue_stack_limits(mddev->queue,

diff .prev/drivers/md/raid1.c ./drivers/md/raid1.c
--- .prev/drivers/md/raid1.c	2008-06-27 15:14:03.000000000 +1000
+++ ./drivers/md/raid1.c	2008-06-27 15:33:01.000000000 +1000
@@ -1103,8 +1103,13 @@ static int raid1_add_disk(mddev_t *mddev
 	int found = 0;
 	int mirror = 0;
 	mirror_info_t *p;
+	int first = 0;
+	int last = mddev->raid_disks - 1;
 
-	for (mirror=0; mirror < mddev->raid_disks; mirror++)
+	if (rdev->raid_disk >= 0)
+		first = last = rdev->raid_disk;
+
+	for (mirror = first; mirror <= last; mirror++)
 		if ( !(p=conf->mirrors+mirror)->rdev) {
 
 			blk_queue_stack_limits(mddev->queue,

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 15:31:23.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 15:33:01.000000000 +1000
@@ -4607,21 +4607,27 @@ static int raid5_add_disk(mddev_t *mddev
 	int found = 0;
 	int disk;
 	struct disk_info *p;
+	int first = 0;
+	int last = conf->raid_disks - 1;
 
 	if (mddev->degraded > conf->max_degraded)
 		/* no point adding a device */
 		return 0;
 
+	if (rdev->raid_disk >= 0)
+		first = last = rdev->raid_disk;
+
 	/*
 	 * find the disk ... but prefer rdev->saved_raid_disk
 	 * if possible.
 	 */
 	if (rdev->saved_raid_disk >= 0 &&
+	    rdev->saved_raid_disk >= first &&
 	    conf->disks[rdev->saved_raid_disk].rdev == NULL)
 		disk = rdev->saved_raid_disk;
 	else
-		disk = 0;
-	for ( ; disk < conf->raid_disks; disk++)
+		disk = first;
+	for ( ; disk <= last ; disk++)
 		if ((p=conf->disks + disk)->rdev == NULL) {
 			clear_bit(In_sync, &rdev->flags);
 			rdev->raid_disk = disk;

[PATCH 012 of 29] md: rationalise return value for ->hot_add_disk method.

[NeilBrown]

For all array types but linear, ->hot_add_disk returns 1 on
success, 0 on failure.
For linear, it returns 0 on success and -errno on failure.

This doesn't cause a functional problem because the ->hot_add_disk
function of linear is used quite differently to the others.
However it is confusing.

So convert all to return 0 for success or -errno on failure
and fix call sites to match.

Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/md.c        |    7 +++----
 ./drivers/md/multipath.c |    8 +++++---
 ./drivers/md/raid1.c     |    6 +++---
 ./drivers/md/raid10.c    |   10 +++++-----
 ./drivers/md/raid5.c     |   10 +++++-----
 5 files changed, 21 insertions(+), 20 deletions(-)

diff .prev/drivers/md/md.c ./drivers/md/md.c
--- .prev/drivers/md/md.c	2008-06-27 16:20:35.000000000 +1000
+++ ./drivers/md/md.c	2008-06-27 16:20:38.000000000 +1000
@@ -1977,10 +1977,8 @@ slot_store(mdk_rdev_t *rdev, const char 
 			rdev->saved_raid_disk = -1;
 		err = rdev->mddev->pers->
 			hot_add_disk(rdev->mddev, rdev);
-		if (err != 1) {
+		if (err) {
 			rdev->raid_disk = -1;
-			if (err == 0)
-				return -EEXIST;
 			return err;
 		}
 		sprintf(nm, "rd%d", rdev->raid_disk);
@@ -5920,7 +5918,8 @@ static int remove_and_add_spares(mddev_t
 			if (rdev->raid_disk < 0
 			    && !test_bit(Faulty, &rdev->flags)) {
 				rdev->recovery_offset = 0;
-				if (mddev->pers->hot_add_disk(mddev,rdev)) {
+				if (mddev->pers->
+				    hot_add_disk(mddev, rdev) == 0) {
 					char nm[20];
 					sprintf(nm, "rd%d", rdev->raid_disk);
 					if (sysfs_create_link(&mddev->kobj,

diff .prev/drivers/md/multipath.c ./drivers/md/multipath.c
--- .prev/drivers/md/multipath.c	2008-06-27 16:20:35.000000000 +1000
+++ ./drivers/md/multipath.c	2008-06-27 16:20:38.000000000 +1000
@@ -281,7 +281,7 @@ static int multipath_add_disk(mddev_t *m
 {
 	multipath_conf_t *conf = mddev->private;
 	struct request_queue *q;
-	int found = 0;
+	int err = -EEXIST;
 	int path;
 	struct multipath_info *p;
 	int first = 0;
@@ -312,11 +312,13 @@ static int multipath_add_disk(mddev_t *m
 			rdev->raid_disk = path;
 			set_bit(In_sync, &rdev->flags);
 			rcu_assign_pointer(p->rdev, rdev);
-			found = 1;
+			err = 0;
+			break;
 		}
 
 	print_multipath_conf(conf);
-	return found;
+
+	return err;
 }
 
 static int multipath_remove_disk(mddev_t *mddev, int number)

diff .prev/drivers/md/raid10.c ./drivers/md/raid10.c
--- .prev/drivers/md/raid10.c	2008-06-27 16:20:35.000000000 +1000
+++ ./drivers/md/raid10.c	2008-06-27 16:20:38.000000000 +1000
@@ -1113,7 +1113,7 @@ static int raid10_spare_active(mddev_t *
 static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 {
 	conf_t *conf = mddev->private;
-	int found = 0;
+	int err = -EEXIST;
 	int mirror;
 	mirror_info_t *p;
 	int first = 0;
@@ -1123,9 +1123,9 @@ static int raid10_add_disk(mddev_t *mdde
 		/* only hot-add to in-sync arrays, as recovery is
 		 * very different from resync
 		 */
-		return 0;
+		return -EBUSY;
 	if (!enough(conf))
-		return 0;
+		return -EINVAL;
 
 	if (rdev->raid_disk)
 		first = last = rdev->raid_disk;
@@ -1151,7 +1151,7 @@ static int raid10_add_disk(mddev_t *mdde
 
 			p->head_position = 0;
 			rdev->raid_disk = mirror;
-			found = 1;
+			err = 0;
 			if (rdev->saved_raid_disk != mirror)
 				conf->fullsync = 1;
 			rcu_assign_pointer(p->rdev, rdev);
@@ -1159,7 +1159,7 @@ static int raid10_add_disk(mddev_t *mdde
 		}
 
 	print_conf(conf);
-	return found;
+	return err;
 }
 
 static int raid10_remove_disk(mddev_t *mddev, int number)

diff .prev/drivers/md/raid1.c ./drivers/md/raid1.c
--- .prev/drivers/md/raid1.c	2008-06-27 16:20:35.000000000 +1000
+++ ./drivers/md/raid1.c	2008-06-27 16:20:38.000000000 +1000
@@ -1100,7 +1100,7 @@ static int raid1_spare_active(mddev_t *m
 static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 {
 	conf_t *conf = mddev->private;
-	int found = 0;
+	int err = -EEXIST;
 	int mirror = 0;
 	mirror_info_t *p;
 	int first = 0;
@@ -1124,7 +1124,7 @@ static int raid1_add_disk(mddev_t *mddev
 
 			p->head_position = 0;
 			rdev->raid_disk = mirror;
-			found = 1;
+			err = 0;
 			/* As all devices are equivalent, we don't need a full recovery
 			 * if this was recently any drive of the array
 			 */
@@ -1135,7 +1135,7 @@ static int raid1_add_disk(mddev_t *mddev
 		}
 
 	print_conf(conf);
-	return found;
+	return err;
 }
 
 static int raid1_remove_disk(mddev_t *mddev, int number)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:20:35.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:20:58.000000000 +1000
@@ -4604,7 +4604,7 @@ abort:
 static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 {
 	raid5_conf_t *conf = mddev->private;
-	int found = 0;
+	int err = -EEXIST;
 	int disk;
 	struct disk_info *p;
 	int first = 0;
@@ -4612,7 +4612,7 @@ static int raid5_add_disk(mddev_t *mddev
 
 	if (mddev->degraded > conf->max_degraded)
 		/* no point adding a device */
-		return 0;
+		return -EINVAL;
 
 	if (rdev->raid_disk >= 0)
 		first = last = rdev->raid_disk;
@@ -4631,14 +4631,14 @@ static int raid5_add_disk(mddev_t *mddev
 		if ((p=conf->disks + disk)->rdev == NULL) {
 			clear_bit(In_sync, &rdev->flags);
 			rdev->raid_disk = disk;
-			found = 1;
+			err = 0;
 			if (rdev->saved_raid_disk != disk)
 				conf->fullsync = 1;
 			rcu_assign_pointer(p->rdev, rdev);
 			break;
 		}
 	print_raid5_conf(conf);
-	return found;
+	return err;
 }
 
 static int raid5_resize(mddev_t *mddev, sector_t sectors)
@@ -4739,7 +4739,7 @@ static int raid5_start_reshape(mddev_t *
 	rdev_for_each(rdev, rtmp, mddev)
 		if (rdev->raid_disk < 0 &&
 		    !test_bit(Faulty, &rdev->flags)) {
-			if (raid5_add_disk(mddev, rdev)) {
+			if (raid5_add_disk(mddev, rdev) == 0) {
 				char nm[20];
 				set_bit(In_sync, &rdev->flags);
 				added_devices++;

[PATCH 013 of 29] md: Don't reject HOT_REMOVE_DISK request for an array that is not yet started.

[NeilBrown]

There is really no need for this test here, and there are valid
cases for selectively removing devices from an array that
it not actually active.

Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/md.c |    3 ---
 1 file changed, 3 deletions(-)

diff .prev/drivers/md/md.c ./drivers/md/md.c
--- .prev/drivers/md/md.c	2008-06-27 16:20:38.000000000 +1000
+++ ./drivers/md/md.c	2008-06-27 16:22:01.000000000 +1000
@@ -4300,9 +4300,6 @@ static int hot_remove_disk(mddev_t * mdd
 	char b[BDEVNAME_SIZE];
 	mdk_rdev_t *rdev;
 
-	if (!mddev->pers)
-		return -ENODEV;
-
 	rdev = find_rdev(mddev, dev);
 	if (!rdev)
 		return -ENXIO;

[PATCH 014 of 29] md: Make sure all changes to md/array_state are notified.

[NeilBrown]

Changes in md/array_state could be of interest to a monitoring
program.  So make sure all changes trigger a notification.

Exceptions:
   changing active_idle to active is not reported because it
      is frequent and not interesting.
   changing active to active_idle is only reported on arrays
      with externally managed metadata, as it is not interesting
      otherwise.
      
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./Documentation/md.txt |    5 +++++
 ./drivers/md/md.c      |   29 ++++++++++++++++++++++++-----
 2 files changed, 29 insertions(+), 5 deletions(-)

diff .prev/Documentation/md.txt ./Documentation/md.txt
--- .prev/Documentation/md.txt	2008-06-27 16:20:34.000000000 +1000
+++ ./Documentation/md.txt	2008-06-27 16:22:01.000000000 +1000
@@ -236,6 +236,11 @@ All md devices contain:
      writing the word for the desired state, however some states
      cannot be explicitly set, and some transitions are not allowed.
 
+     Select/poll works on this file.  All changes except between
+     	active_idle and active (which can be frequent and are not
+	very interesting) are notified.  active->active_idle is
+	reported if the metadata is externally managed.
+
      clear
          No devices, no size, no level
          Writing is equivalent to STOP_ARRAY ioctl

diff .prev/drivers/md/md.c ./drivers/md/md.c
--- .prev/drivers/md/md.c	2008-06-27 16:22:01.000000000 +1000
+++ ./drivers/md/md.c	2008-06-27 16:22:01.000000000 +1000
@@ -2716,8 +2716,10 @@ array_state_store(mddev_t *mddev, const 
 	}
 	if (err)
 		return err;
-	else
+	else {
+		sysfs_notify(&mddev->kobj, NULL, "array_state");
 		return len;
+	}
 }
 static struct md_sysfs_entry md_array_state =
 __ATTR(array_state, S_IRUGO|S_IWUSR, array_state_show, array_state_store);
@@ -3408,7 +3410,11 @@ static void md_safemode_timeout(unsigned
 {
 	mddev_t *mddev = (mddev_t *) data;
 
-	mddev->safemode = 1;
+	if (!atomic_read(&mddev->writes_pending)) {
+		mddev->safemode = 1;
+		if (mddev->external)
+			sysfs_notify(&mddev->kobj, NULL, "array_state");
+	}
 	md_wakeup_thread(mddev->thread);
 }
 
@@ -3675,6 +3681,7 @@ static int do_md_run(mddev_t * mddev)
 
 	mddev->changed = 1;
 	md_new_event(mddev);
+	sysfs_notify(&mddev->kobj, NULL, "array_state");
 	kobject_uevent(&mddev->gendisk->dev.kobj, KOBJ_CHANGE);
 	return 0;
 }
@@ -3709,6 +3716,8 @@ static int restart_array(mddev_t *mddev)
 		md_wakeup_thread(mddev->thread);
 		md_wakeup_thread(mddev->sync_thread);
 		err = 0;
+		sysfs_notify(&mddev->kobj, NULL, "array_state");
+
 	} else
 		err = -EINVAL;
 
@@ -3879,6 +3888,7 @@ static int do_md_stop(mddev_t * mddev, i
 			mdname(mddev));
 	err = 0;
 	md_new_event(mddev);
+	sysfs_notify(&mddev->kobj, NULL, "array_state");
 out:
 	return err;
 }
@@ -4876,8 +4886,9 @@ static int md_ioctl(struct inode *inode,
 	    mddev->ro && mddev->pers) {
 		if (mddev->ro == 2) {
 			mddev->ro = 0;
-		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
-		md_wakeup_thread(mddev->thread);
+			sysfs_notify(&mddev->kobj, NULL, "array_state");
+			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+			md_wakeup_thread(mddev->thread);
 
 		} else {
 			err = -EROFS;
@@ -5516,6 +5527,7 @@ void md_done_sync(mddev_t *mddev, int bl
  */
 void md_write_start(mddev_t *mddev, struct bio *bi)
 {
+	int did_change = 0;
 	if (bio_data_dir(bi) != WRITE)
 		return;
 
@@ -5526,6 +5538,7 @@ void md_write_start(mddev_t *mddev, stru
 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 		md_wakeup_thread(mddev->thread);
 		md_wakeup_thread(mddev->sync_thread);
+		did_change = 1;
 	}
 	atomic_inc(&mddev->writes_pending);
 	if (mddev->safemode == 1)
@@ -5536,10 +5549,12 @@ void md_write_start(mddev_t *mddev, stru
 			mddev->in_sync = 0;
 			set_bit(MD_CHANGE_CLEAN, &mddev->flags);
 			md_wakeup_thread(mddev->thread);
+			did_change = 1;
 		}
 		spin_unlock_irq(&mddev->write_lock);
-		sysfs_notify(&mddev->kobj, NULL, "array_state");
 	}
+	if (did_change)
+		sysfs_notify(&mddev->kobj, NULL, "array_state");
 	wait_event(mddev->sb_wait,
 		   !test_bit(MD_CHANGE_CLEAN, &mddev->flags) &&
 		   !test_bit(MD_CHANGE_PENDING, &mddev->flags));
@@ -5991,18 +6006,22 @@ void md_check_recovery(mddev_t *mddev)
 		int spares = 0;
 
 		if (!mddev->external) {
+			int did_change = 0;
 			spin_lock_irq(&mddev->write_lock);
 			if (mddev->safemode &&
 			    !atomic_read(&mddev->writes_pending) &&
 			    !mddev->in_sync &&
 			    mddev->recovery_cp == MaxSector) {
 				mddev->in_sync = 1;
+				did_change = 1;
 				if (mddev->persistent)
 					set_bit(MD_CHANGE_CLEAN, &mddev->flags);
 			}
 			if (mddev->safemode == 1)
 				mddev->safemode = 0;
 			spin_unlock_irq(&mddev->write_lock);
+			if (did_change)
+				sysfs_notify(&mddev->kobj, NULL, "array_state");
 		}
 
 		if (mddev->flags)

[PATCH 015 of 29] md: Make sure all changes to md/sync_action are notified.

[NeilBrown]

When the 'resync' thread starts or stops, when we explicitly
set sync_action, or when we determine that there is definitely nothing
to do, we notify sync_action.

To stop "sync_action" from occasionally showing the wrong value,
we introduce a new flags - MD_RECOVERY_RECOVER - to say that a 
recovery is probably needed or happening, and we make sure
that we set MD_RECOVERY_RUNNING before clearing MD_RECOVERY_NEEDED.

Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./Documentation/md.txt      |    6 ++++++
 ./drivers/md/md.c           |   34 ++++++++++++++++++++++++++++------
 ./include/linux/raid/md_k.h |    2 ++
 3 files changed, 36 insertions(+), 6 deletions(-)

diff .prev/Documentation/md.txt ./Documentation/md.txt
--- .prev/Documentation/md.txt	2008-06-27 16:22:01.000000000 +1000
+++ ./Documentation/md.txt	2008-06-27 16:22:02.000000000 +1000
@@ -386,6 +386,12 @@ also have
 	'check' and 'repair' will start the appropriate process
            providing the current state is 'idle'.
 
+      This file responds to select/poll.  Any important change in the value
+      triggers a poll event.  Sometimes the value will briefly be
+      "recover" if a recovery seems to be needed, but cannot be
+      achieved. In that case, the transition to "recover" isn't
+      notified, but the transition away is.
+
    mismatch_count
       When performing 'check' and 'repair', and possibly when
       performing 'resync', md will count the number of errors that are

diff .prev/drivers/md/md.c ./drivers/md/md.c
--- .prev/drivers/md/md.c	2008-06-27 16:22:01.000000000 +1000
+++ ./drivers/md/md.c	2008-06-27 16:22:02.000000000 +1000
@@ -169,7 +169,6 @@ void md_new_event(mddev_t *mddev)
 {
 	atomic_inc(&md_event_count);
 	wake_up(&md_event_waiters);
-	sysfs_notify(&mddev->kobj, NULL, "sync_action");
 }
 EXPORT_SYMBOL_GPL(md_new_event);
 
@@ -2936,7 +2935,7 @@ action_show(mddev_t *mddev, char *page)
 				type = "check";
 			else
 				type = "repair";
-		} else
+		} else if (test_bit(MD_RECOVERY_RECOVER, &mddev->recovery))
 			type = "recover";
 	}
 	return sprintf(page, "%s\n", type);
@@ -2958,9 +2957,12 @@ action_store(mddev_t *mddev, const char 
 	} else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
 		   test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
 		return -EBUSY;
-	else if (cmd_match(page, "resync") || cmd_match(page, "recover"))
+	else if (cmd_match(page, "resync"))
+		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+	else if (cmd_match(page, "recover")) {
+		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
-	else if (cmd_match(page, "reshape")) {
+	} else if (cmd_match(page, "reshape")) {
 		int err;
 		if (mddev->pers->start_reshape == NULL)
 			return -EINVAL;
@@ -2977,6 +2979,7 @@ action_store(mddev_t *mddev, const char 
 	}
 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 	md_wakeup_thread(mddev->thread);
+	sysfs_notify(&mddev->kobj, NULL, "sync_action");
 	return len;
 }
 
@@ -3682,6 +3685,7 @@ static int do_md_run(mddev_t * mddev)
 	mddev->changed = 1;
 	md_new_event(mddev);
 	sysfs_notify(&mddev->kobj, NULL, "array_state");
+	sysfs_notify(&mddev->kobj, NULL, "sync_action");
 	kobject_uevent(&mddev->gendisk->dev.kobj, KOBJ_CHANGE);
 	return 0;
 }
@@ -4252,6 +4256,8 @@ static int add_new_disk(mddev_t * mddev,
 			export_rdev(rdev);
 
 		md_update_sb(mddev, 1);
+		if (mddev->degraded)
+			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 		md_wakeup_thread(mddev->thread);
 		return err;
@@ -5105,6 +5111,8 @@ void md_error(mddev_t *mddev, mdk_rdev_t
 	if (!mddev->pers->error_handler)
 		return;
 	mddev->pers->error_handler(mddev,rdev);
+	if (mddev->degraded)
+		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 	md_wakeup_thread(mddev->thread);
@@ -6055,13 +6063,18 @@ void md_check_recovery(mddev_t *mddev)
 			mddev->recovery = 0;
 			/* flag recovery needed just to double check */
 			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+			sysfs_notify(&mddev->kobj, NULL, "sync_action");
 			md_new_event(mddev);
 			goto unlock;
 		}
+		/* Set RUNNING before clearing NEEDED to avoid
+		 * any transients in the value of "sync_action".
+		 */
+		set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
+		clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 		/* Clear some bits that don't mean anything, but
 		 * might be left set
 		 */
-		clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 		clear_bit(MD_RECOVERY_INTR, &mddev->recovery);
 		clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
 
@@ -6079,17 +6092,19 @@ void md_check_recovery(mddev_t *mddev)
 				/* Cannot proceed */
 				goto unlock;
 			set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
+			clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
 		} else if ((spares = remove_and_add_spares(mddev))) {
 			clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
 			clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
+			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
 		} else if (mddev->recovery_cp < MaxSector) {
 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
+			clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
 		} else if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
 			/* nothing to be done ... */
 			goto unlock;
 
 		if (mddev->pers->sync_request) {
-			set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
 			if (spares && mddev->bitmap && ! mddev->bitmap->file) {
 				/* We are adding a device or devices to an array
 				 * which has the bitmap stored on all devices.
@@ -6108,9 +6123,16 @@ void md_check_recovery(mddev_t *mddev)
 				mddev->recovery = 0;
 			} else
 				md_wakeup_thread(mddev->sync_thread);
+			sysfs_notify(&mddev->kobj, NULL, "sync_action");
 			md_new_event(mddev);
 		}
 	unlock:
+		if (!mddev->sync_thread) {
+			clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
+			if (test_and_clear_bit(MD_RECOVERY_RECOVER,
+					       &mddev->recovery))
+				sysfs_notify(&mddev->kobj, NULL, "sync_action");
+		}
 		mddev_unlock(mddev);
 	}
 }

diff .prev/include/linux/raid/md_k.h ./include/linux/raid/md_k.h
--- .prev/include/linux/raid/md_k.h	2008-06-27 16:20:34.000000000 +1000
+++ ./include/linux/raid/md_k.h	2008-06-27 16:22:02.000000000 +1000
@@ -188,6 +188,7 @@ struct mddev_s
 	 * NEEDED:   we might need to start a resync/recover
 	 * RUNNING:  a thread is running, or about to be started
 	 * SYNC:     actually doing a resync, not a recovery
+	 * RECOVER:  doing recovery, or need to try it.
 	 * INTR:     resync needs to be aborted for some reason
 	 * DONE:     thread is done and is waiting to be reaped
 	 * REQUEST:  user-space has requested a sync (used with SYNC)
@@ -198,6 +199,7 @@ struct mddev_s
 	 */
 #define	MD_RECOVERY_RUNNING	0
 #define	MD_RECOVERY_SYNC	1
+#define	MD_RECOVERY_RECOVER	2
 #define	MD_RECOVERY_INTR	3
 #define	MD_RECOVERY_DONE	4
 #define	MD_RECOVERY_NEEDED	5

[PATCH 016 of 29] md: Make sure all changes to md/degraded are notified.

[NeilBrown]

When a device fails, when a spare is activated, when
an array is reshaped, or when an array is started,
the extent to which the array is degraded can change.

Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./Documentation/md.txt |    7 +++++++
 ./drivers/md/md.c      |    6 +++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff .prev/Documentation/md.txt ./Documentation/md.txt
--- .prev/Documentation/md.txt	2008-06-27 16:22:02.000000000 +1000
+++ ./Documentation/md.txt	2008-06-27 16:22:02.000000000 +1000
@@ -392,6 +392,13 @@ also have
       achieved. In that case, the transition to "recover" isn't
       notified, but the transition away is.
 
+   degraded
+      This contains a count of the number of devices by which the
+      arrays is degraded.  So an optimal array with show '0'.  A
+      single failed/missing drive will show '1', etc.
+      This file responds to select/poll, any increase or decrease
+      in the count of missing devices will trigger an event.
+
    mismatch_count
       When performing 'check' and 'repair', and possibly when
       performing 'resync', md will count the number of errors that are

diff .prev/drivers/md/md.c ./drivers/md/md.c
--- .prev/drivers/md/md.c	2008-06-27 16:22:02.000000000 +1000
+++ ./drivers/md/md.c	2008-06-27 16:22:02.000000000 +1000
@@ -2969,6 +2969,7 @@ action_store(mddev_t *mddev, const char 
 		err = mddev->pers->start_reshape(mddev);
 		if (err)
 			return err;
+		sysfs_notify(&mddev->kobj, NULL, "degraded");
 	} else {
 		if (cmd_match(page, "check"))
 			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
@@ -3686,6 +3687,7 @@ static int do_md_run(mddev_t * mddev)
 	md_new_event(mddev);
 	sysfs_notify(&mddev->kobj, NULL, "array_state");
 	sysfs_notify(&mddev->kobj, NULL, "sync_action");
+	sysfs_notify(&mddev->kobj, NULL, "degraded");
 	kobject_uevent(&mddev->gendisk->dev.kobj, KOBJ_CHANGE);
 	return 0;
 }
@@ -6049,7 +6051,9 @@ void md_check_recovery(mddev_t *mddev)
 			if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
 				/* success...*/
 				/* activate any spares */
-				mddev->pers->spare_active(mddev);
+				if (mddev->pers->spare_active(mddev))
+					sysfs_notify(&mddev->kobj, NULL,
+						     "degraded");
 			}
 			md_update_sb(mddev, 1);
 

[PATCH 017 of 29] md: Make sure all changes to md/dev-XX/state are notified

[NeilBrown]

The important state change happens during an interrupt
in md_error.  So just set a flag there and call sysfs_notify
later in process context.

Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./Documentation/md.txt      |   10 ++++++++++
 ./drivers/md/md.c           |   14 +++++++++++++-
 ./include/linux/raid/md_k.h |    3 +++
 3 files changed, 26 insertions(+), 1 deletion(-)

diff .prev/Documentation/md.txt ./Documentation/md.txt
--- .prev/Documentation/md.txt	2008-06-27 16:22:02.000000000 +1000
+++ ./Documentation/md.txt	2008-06-27 16:22:03.000000000 +1000
@@ -297,6 +297,10 @@ Each directory contains:
 	      writemostly - device will only be subject to read
 		         requests if there are no other options.
 			 This applies only to raid1 arrays.
+	      blocked  - device has failed, metadata is "external",
+	                 and the failure hasn't been acknowledged yet.
+			 Writes that would write to this device if
+			 it were not faulty are blocked.
 	      spare    - device is working, but not a full member.
 			 This includes spares that are in the process
 			 of being recovered to
@@ -306,6 +310,12 @@ Each directory contains:
 	Writing "remove" removes the device from the array.
 	Writing "writemostly" sets the writemostly flag.
 	Writing "-writemostly" clears the writemostly flag.
+	Writing "blocked" sets the "blocked" flag.
+	Writing "-blocked" clear the "blocked" flag and allows writes
+		to complete.
+
+	This file responds to select/poll. Any change to 'faulty'
+	or 'blocked' causes an event.
 
       errors
 	An approximate count of read errors that have been detected on

diff .prev/drivers/md/md.c ./drivers/md/md.c
--- .prev/drivers/md/md.c	2008-06-27 16:22:02.000000000 +1000
+++ ./drivers/md/md.c	2008-06-27 16:22:03.000000000 +1000
@@ -1886,6 +1886,8 @@ state_store(mdk_rdev_t *rdev, const char
 
 		err = 0;
 	}
+	if (!err)
+		sysfs_notify(&rdev->kobj, NULL, "state");
 	return err ? err : len;
 }
 static struct rdev_sysfs_entry rdev_state =
@@ -1979,7 +1981,8 @@ slot_store(mdk_rdev_t *rdev, const char 
 		if (err) {
 			rdev->raid_disk = -1;
 			return err;
-		}
+		} else
+			sysfs_notify(&rdev->kobj, NULL, "state");
 		sprintf(nm, "rd%d", rdev->raid_disk);
 		if (sysfs_create_link(&rdev->mddev->kobj, &rdev->kobj, nm))
 			printk(KERN_WARNING
@@ -1996,6 +1999,7 @@ slot_store(mdk_rdev_t *rdev, const char 
 		clear_bit(Faulty, &rdev->flags);
 		clear_bit(WriteMostly, &rdev->flags);
 		set_bit(In_sync, &rdev->flags);
+		sysfs_notify(&rdev->kobj, NULL, "state");
 	}
 	return len;
 }
@@ -3525,6 +3529,7 @@ static int do_md_run(mddev_t * mddev)
 				return -EINVAL;
 			}
 		}
+		sysfs_notify(&rdev->kobj, NULL, "state");
 	}
 
 	md_probe(mddev->unit, NULL, NULL);
@@ -4256,6 +4261,8 @@ static int add_new_disk(mddev_t * mddev,
 		}
 		if (err)
 			export_rdev(rdev);
+		else
+			sysfs_notify(&rdev->kobj, NULL, "state");
 
 		md_update_sb(mddev, 1);
 		if (mddev->degraded)
@@ -5115,6 +5122,7 @@ void md_error(mddev_t *mddev, mdk_rdev_t
 	mddev->pers->error_handler(mddev,rdev);
 	if (mddev->degraded)
 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
+	set_bit(StateChanged, &rdev->flags);
 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 	md_wakeup_thread(mddev->thread);
@@ -6037,6 +6045,10 @@ void md_check_recovery(mddev_t *mddev)
 		if (mddev->flags)
 			md_update_sb(mddev, 0);
 
+		rdev_for_each(rdev, rtmp, mddev)
+			if (test_and_clear_bit(StateChanged, &rdev->flags))
+				sysfs_notify(&rdev->kobj, NULL, "state");
+
 
 		if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
 		    !test_bit(MD_RECOVERY_DONE, &mddev->recovery)) {

diff .prev/include/linux/raid/md_k.h ./include/linux/raid/md_k.h
--- .prev/include/linux/raid/md_k.h	2008-06-27 16:22:02.000000000 +1000
+++ ./include/linux/raid/md_k.h	2008-06-27 16:22:03.000000000 +1000
@@ -87,6 +87,9 @@ struct mdk_rdev_s
 #define Blocked		8		/* An error occured on an externally
 					 * managed array, don't allow writes
 					 * until it is cleared */
+#define StateChanged	9		/* Faulty or Blocked has changed during
+					 * interrupt, so it needs to be
+					 * notified by the thread */
 	wait_queue_head_t blocked_wait;
 
 	int desc_nr;			/* descriptor index in the superblock */

[PATCH 018 of 29] md: Support changing rdev size on running arrays.

[NeilBrown]

From: Chris Webb <chris@arachsys.com>

Allow /sys/block/mdX/md/rdY/size to change on running arrays, moving the
superblock if necessary for this metadata version. We prevent the available
space from shrinking to less than the used size, and allow it to be set to zero
to fill all the available space on the underlying device.

Signed-off-by: Chris Webb <chris@arachsys.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/md.c |  100 ++++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 87 insertions(+), 13 deletions(-)

diff .prev/drivers/md/md.c ./drivers/md/md.c
--- .prev/drivers/md/md.c	2008-06-27 16:22:03.000000000 +1000
+++ ./drivers/md/md.c	2008-06-27 16:22:03.000000000 +1000
@@ -658,11 +658,14 @@ static unsigned int calc_sb_csum(mdp_sup
  */
 
 struct super_type  {
-	char 		*name;
-	struct module	*owner;
-	int		(*load_super)(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version);
-	int		(*validate_super)(mddev_t *mddev, mdk_rdev_t *rdev);
-	void		(*sync_super)(mddev_t *mddev, mdk_rdev_t *rdev);
+	char		    *name;
+	struct module	    *owner;
+	int		    (*load_super)(mdk_rdev_t *rdev, mdk_rdev_t *refdev,
+					  int minor_version);
+	int		    (*validate_super)(mddev_t *mddev, mdk_rdev_t *rdev);
+	void		    (*sync_super)(mddev_t *mddev, mdk_rdev_t *rdev);
+	unsigned long long  (*rdev_size_change)(mdk_rdev_t *rdev,
+						unsigned long long size);
 };
 
 /*
@@ -1004,6 +1007,27 @@ static void super_90_sync(mddev_t *mddev
 }
 
 /*
+ * rdev_size_change for 0.90.0
+ */
+static unsigned long long
+super_90_rdev_size_change(mdk_rdev_t *rdev, unsigned long long size)
+{
+	if (size && size < rdev->mddev->size)
+		return 0; /* component must fit device */
+	size *= 2; /* convert to sectors */
+	if (rdev->mddev->bitmap_offset)
+		return 0; /* can't move bitmap */
+	rdev->sb_offset = calc_dev_sboffset(rdev->bdev);
+	if (!size || size > rdev->sb_offset*2)
+		size = rdev->sb_offset*2;
+	md_super_write(rdev->mddev, rdev, rdev->sb_offset << 1, rdev->sb_size,
+		       rdev->sb_page);
+	md_super_wait(rdev->mddev);
+	return size/2; /* kB for sysfs */
+}
+
+
+/*
  * version 1 superblock
  */
 
@@ -1328,21 +1352,59 @@ static void super_1_sync(mddev_t *mddev,
 	sb->sb_csum = calc_sb_1_csum(sb);
 }
 
+static unsigned long long
+super_1_rdev_size_change(mdk_rdev_t *rdev, unsigned long long size)
+{
+	struct mdp_superblock_1 *sb;
+	unsigned long long max_size;
+	if (size && size < rdev->mddev->size)
+		return 0; /* component must fit device */
+	size *= 2; /* convert to sectors */
+	if (rdev->sb_offset < rdev->data_offset/2) {
+		/* minor versions 1 and 2; superblock before data */
+		max_size = (rdev->bdev->bd_inode->i_size >> 9);
+		max_size -= rdev->data_offset;
+		if (!size || size > max_size)
+			size = max_size;
+	} else if (rdev->mddev->bitmap_offset) {
+		/* minor version 0 with bitmap we can't move */
+		return 0;
+	} else {
+		/* minor version 0; superblock after data */
+		sector_t sb_offset;
+		sb_offset = (rdev->bdev->bd_inode->i_size >> 9) - 8*2;
+		sb_offset &= ~(sector_t)(4*2 - 1);
+		max_size = rdev->size*2 + sb_offset - rdev->sb_offset*2;
+		if (!size || size > max_size)
+			size = max_size;
+		rdev->sb_offset = sb_offset/2;
+	}
+	sb = (struct mdp_superblock_1 *) page_address(rdev->sb_page);
+	sb->data_size = cpu_to_le64(size);
+	sb->super_offset = rdev->sb_offset*2;
+	sb->sb_csum = calc_sb_1_csum(sb);
+	md_super_write(rdev->mddev, rdev, rdev->sb_offset << 1, rdev->sb_size,
+		       rdev->sb_page);
+	md_super_wait(rdev->mddev);
+	return size/2; /* kB for sysfs */
+}
 
 static struct super_type super_types[] = {
 	[0] = {
 		.name	= "0.90.0",
 		.owner	= THIS_MODULE,
-		.load_super	= super_90_load,
-		.validate_super	= super_90_validate,
-		.sync_super	= super_90_sync,
+		.load_super	    = super_90_load,
+		.validate_super	    = super_90_validate,
+		.sync_super	    = super_90_sync,
+		.rdev_size_change   = super_90_rdev_size_change,
 	},
 	[1] = {
 		.name	= "md-1",
 		.owner	= THIS_MODULE,
-		.load_super	= super_1_load,
-		.validate_super	= super_1_validate,
-		.sync_super	= super_1_sync,
+		.load_super	    = super_1_load,
+		.validate_super	    = super_1_validate,
+		.sync_super	    = super_1_sync,
+		.rdev_size_change   = super_1_rdev_size_change,
 	},
 };
 
@@ -2060,8 +2122,20 @@ rdev_size_store(mdk_rdev_t *rdev, const 
 
 	if (e==buf || (*e && *e != '\n'))
 		return -EINVAL;
-	if (my_mddev->pers && rdev->raid_disk >= 0)
-		return -EBUSY;
+	if (my_mddev->pers && rdev->raid_disk >= 0) {
+		if (rdev->mddev->persistent) {
+			size = super_types[rdev->mddev->major_version].
+				rdev_size_change(rdev, size);
+			if (!size)
+				return -EBUSY;
+		} else if (!size) {
+			size = (rdev->bdev->bd_inode->i_size >> 10);
+			size -= rdev->data_offset/2;
+		}
+		if (size < rdev->mddev->size)
+			return -EINVAL; /* component must fit device */
+	}
+
 	rdev->size = size;
 	if (size > oldsize && rdev->mddev->external) {
 		/* need to check that all other rdevs with the same ->bdev

[PATCH 018 of 29] md: Support changing rdev size on running arrays.

[NeilBrown]

From: Chris Webb <chris@arachsys.com>

Allow /sys/block/mdX/md/rdY/size to change on running arrays, moving the
superblock if necessary for this metadata version. We prevent the available
space from shrinking to less than the used size, and allow it to be set to zero
to fill all the available space on the underlying device.

Signed-off-by: Chris Webb <chris@arachsys.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/md.c |  100 ++++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 87 insertions(+), 13 deletions(-)

diff .prev/drivers/md/md.c ./drivers/md/md.c
--- .prev/drivers/md/md.c	2008-06-27 16:22:03.000000000 +1000
+++ ./drivers/md/md.c	2008-06-27 16:22:03.000000000 +1000
@@ -658,11 +658,14 @@ static unsigned int calc_sb_csum(mdp_sup
  */
 
 struct super_type  {
-	char 		*name;
-	struct module	*owner;
-	int		(*load_super)(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version);
-	int		(*validate_super)(mddev_t *mddev, mdk_rdev_t *rdev);
-	void		(*sync_super)(mddev_t *mddev, mdk_rdev_t *rdev);
+	char		    *name;
+	struct module	    *owner;
+	int		    (*load_super)(mdk_rdev_t *rdev, mdk_rdev_t *refdev,
+					  int minor_version);
+	int		    (*validate_super)(mddev_t *mddev, mdk_rdev_t *rdev);
+	void		    (*sync_super)(mddev_t *mddev, mdk_rdev_t *rdev);
+	unsigned long long  (*rdev_size_change)(mdk_rdev_t *rdev,
+						unsigned long long size);
 };
 
 /*
@@ -1004,6 +1007,27 @@ static void super_90_sync(mddev_t *mddev
 }
 
 /*
+ * rdev_size_change for 0.90.0
+ */
+static unsigned long long
+super_90_rdev_size_change(mdk_rdev_t *rdev, unsigned long long size)
+{
+	if (size && size < rdev->mddev->size)
+		return 0; /* component must fit device */
+	size *= 2; /* convert to sectors */
+	if (rdev->mddev->bitmap_offset)
+		return 0; /* can't move bitmap */
+	rdev->sb_offset = calc_dev_sboffset(rdev->bdev);
+	if (!size || size > rdev->sb_offset*2)
+		size = rdev->sb_offset*2;
+	md_super_write(rdev->mddev, rdev, rdev->sb_offset << 1, rdev->sb_size,
+		       rdev->sb_page);
+	md_super_wait(rdev->mddev);
+	return size/2; /* kB for sysfs */
+}
+
+
+/*
  * version 1 superblock
  */
 
@@ -1328,21 +1352,59 @@ static void super_1_sync(mddev_t *mddev,
 	sb->sb_csum = calc_sb_1_csum(sb);
 }
 
+static unsigned long long
+super_1_rdev_size_change(mdk_rdev_t *rdev, unsigned long long size)
+{
+	struct mdp_superblock_1 *sb;
+	unsigned long long max_size;
+	if (size && size < rdev->mddev->size)
+		return 0; /* component must fit device */
+	size *= 2; /* convert to sectors */
+	if (rdev->sb_offset < rdev->data_offset/2) {
+		/* minor versions 1 and 2; superblock before data */
+		max_size = (rdev->bdev->bd_inode->i_size >> 9);
+		max_size -= rdev->data_offset;
+		if (!size || size > max_size)
+			size = max_size;
+	} else if (rdev->mddev->bitmap_offset) {
+		/* minor version 0 with bitmap we can't move */
+		return 0;
+	} else {
+		/* minor version 0; superblock after data */
+		sector_t sb_offset;
+		sb_offset = (rdev->bdev->bd_inode->i_size >> 9) - 8*2;
+		sb_offset &= ~(sector_t)(4*2 - 1);
+		max_size = rdev->size*2 + sb_offset - rdev->sb_offset*2;
+		if (!size || size > max_size)
+			size = max_size;
+		rdev->sb_offset = sb_offset/2;
+	}
+	sb = (struct mdp_superblock_1 *) page_address(rdev->sb_page);
+	sb->data_size = cpu_to_le64(size);
+	sb->super_offset = rdev->sb_offset*2;
+	sb->sb_csum = calc_sb_1_csum(sb);
+	md_super_write(rdev->mddev, rdev, rdev->sb_offset << 1, rdev->sb_size,
+		       rdev->sb_page);
+	md_super_wait(rdev->mddev);
+	return size/2; /* kB for sysfs */
+}
 
 static struct super_type super_types[] = {
 	[0] = {
 		.name	= "0.90.0",
 		.owner	= THIS_MODULE,
-		.load_super	= super_90_load,
-		.validate_super	= super_90_validate,
-		.sync_super	= super_90_sync,
+		.load_super	    = super_90_load,
+		.validate_super	    = super_90_validate,
+		.sync_super	    = super_90_sync,
+		.rdev_size_change   = super_90_rdev_size_change,
 	},
 	[1] = {
 		.name	= "md-1",
 		.owner	= THIS_MODULE,
-		.load_super	= super_1_load,
-		.validate_super	= super_1_validate,
-		.sync_super	= super_1_sync,
+		.load_super	    = super_1_load,
+		.validate_super	    = super_1_validate,
+		.sync_super	    = super_1_sync,
+		.rdev_size_change   = super_1_rdev_size_change,
 	},
 };
 
@@ -2060,8 +2122,20 @@ rdev_size_store(mdk_rdev_t *rdev, const 
 
 	if (e==buf || (*e && *e != '\n'))
 		return -EINVAL;
-	if (my_mddev->pers && rdev->raid_disk >= 0)
-		return -EBUSY;
+	if (my_mddev->pers && rdev->raid_disk >= 0) {
+		if (rdev->mddev->persistent) {
+			size = super_types[rdev->mddev->major_version].
+				rdev_size_change(rdev, size);
+			if (!size)
+				return -EBUSY;
+		} else if (!size) {
+			size = (rdev->bdev->bd_inode->i_size >> 10);
+			size -= rdev->data_offset/2;
+		}
+		if (size < rdev->mddev->size)
+			return -EINVAL; /* component must fit device */
+	}
+
 	rdev->size = size;
 	if (size > oldsize && rdev->mddev->external) {
 		/* need to check that all other rdevs with the same ->bdev

[PATCH 019 of 29] md: md: kill STRIPE_OP_MOD_DMA in raid5 offload

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

This micro-optimization allowed the raid code to skip a re-read of the
parity block after checking parity.  It took advantage of the fact that
xor-offload-engines have their own internal result buffer and can check
parity without writing to memory.  Remove it for the following reasons:

1/ It is a layering violation for MD to need to manage the DMA and
   non-DMA paths within async_xor_zero_sum
2/ Bad precedent to toggle the 'ops' flags outside the lock
3/ Hard to realize a performance gain as reads will not need an updated
   parity block and writes will dirty it anyways.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c         |   10 ----------
 ./include/linux/raid/raid5.h |    2 --
 2 files changed, 12 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:20:58.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:22:03.000000000 +1000
@@ -837,15 +837,10 @@ ops_run_postxor(struct stripe_head *sh, 
 static void ops_complete_check(void *stripe_head_ref)
 {
 	struct stripe_head *sh = stripe_head_ref;
-	int pd_idx = sh->pd_idx;
 
 	pr_debug("%s: stripe %llu\n", __func__,
 		(unsigned long long)sh->sector);
 
-	if (test_and_clear_bit(STRIPE_OP_MOD_DMA_CHECK, &sh->ops.pending) &&
-		sh->ops.zero_sum_result == 0)
-		set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
-
 	set_bit(STRIPE_OP_CHECK, &sh->ops.complete);
 	set_bit(STRIPE_HANDLE, &sh->state);
 	release_stripe(sh);
@@ -873,11 +868,6 @@ static void ops_run_check(struct stripe_
 	tx = async_xor_zero_sum(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
 		&sh->ops.zero_sum_result, 0, NULL, NULL, NULL);
 
-	if (tx)
-		set_bit(STRIPE_OP_MOD_DMA_CHECK, &sh->ops.pending);
-	else
-		clear_bit(STRIPE_OP_MOD_DMA_CHECK, &sh->ops.pending);
-
 	atomic_inc(&sh->count);
 	tx = async_trigger_callback(ASYNC_TX_DEP_ACK | ASYNC_TX_ACK, tx,
 		ops_complete_check, sh);

diff .prev/include/linux/raid/raid5.h ./include/linux/raid/raid5.h
--- .prev/include/linux/raid/raid5.h	2008-06-27 16:20:33.000000000 +1000
+++ ./include/linux/raid/raid5.h	2008-06-27 16:22:03.000000000 +1000
@@ -267,10 +267,8 @@ struct r6_state {
 
 /* modifiers to the base operations
  * STRIPE_OP_MOD_REPAIR_PD - compute the parity block and write it back
- * STRIPE_OP_MOD_DMA_CHECK - parity is not corrupted by the check
  */
 #define STRIPE_OP_MOD_REPAIR_PD 7
-#define STRIPE_OP_MOD_DMA_CHECK 8
 
 /*
  * Plugging:

[PATCH 019 of 29] md: md: kill STRIPE_OP_MOD_DMA in raid5 offload

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

This micro-optimization allowed the raid code to skip a re-read of the
parity block after checking parity.  It took advantage of the fact that
xor-offload-engines have their own internal result buffer and can check
parity without writing to memory.  Remove it for the following reasons:

1/ It is a layering violation for MD to need to manage the DMA and
   non-DMA paths within async_xor_zero_sum
2/ Bad precedent to toggle the 'ops' flags outside the lock
3/ Hard to realize a performance gain as reads will not need an updated
   parity block and writes will dirty it anyways.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c         |   10 ----------
 ./include/linux/raid/raid5.h |    2 --
 2 files changed, 12 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:20:58.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:22:03.000000000 +1000
@@ -837,15 +837,10 @@ ops_run_postxor(struct stripe_head *sh, 
 static void ops_complete_check(void *stripe_head_ref)
 {
 	struct stripe_head *sh = stripe_head_ref;
-	int pd_idx = sh->pd_idx;
 
 	pr_debug("%s: stripe %llu\n", __func__,
 		(unsigned long long)sh->sector);
 
-	if (test_and_clear_bit(STRIPE_OP_MOD_DMA_CHECK, &sh->ops.pending) &&
-		sh->ops.zero_sum_result == 0)
-		set_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
-
 	set_bit(STRIPE_OP_CHECK, &sh->ops.complete);
 	set_bit(STRIPE_HANDLE, &sh->state);
 	release_stripe(sh);
@@ -873,11 +868,6 @@ static void ops_run_check(struct stripe_
 	tx = async_xor_zero_sum(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
 		&sh->ops.zero_sum_result, 0, NULL, NULL, NULL);
 
-	if (tx)
-		set_bit(STRIPE_OP_MOD_DMA_CHECK, &sh->ops.pending);
-	else
-		clear_bit(STRIPE_OP_MOD_DMA_CHECK, &sh->ops.pending);
-
 	atomic_inc(&sh->count);
 	tx = async_trigger_callback(ASYNC_TX_DEP_ACK | ASYNC_TX_ACK, tx,
 		ops_complete_check, sh);

diff .prev/include/linux/raid/raid5.h ./include/linux/raid/raid5.h
--- .prev/include/linux/raid/raid5.h	2008-06-27 16:20:33.000000000 +1000
+++ ./include/linux/raid/raid5.h	2008-06-27 16:22:03.000000000 +1000
@@ -267,10 +267,8 @@ struct r6_state {
 
 /* modifiers to the base operations
  * STRIPE_OP_MOD_REPAIR_PD - compute the parity block and write it back
- * STRIPE_OP_MOD_DMA_CHECK - parity is not corrupted by the check
  */
 #define STRIPE_OP_MOD_REPAIR_PD 7
-#define STRIPE_OP_MOD_DMA_CHECK 8
 
 /*
  * Plugging:

[PATCH 020 of 29] md: md: kill STRIPE_OP_IO flag

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

The R5_Want{Read,Write} flags already gate i/o.  So, this flag is
superfluous and we can unconditionally call ops_run_io().

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c         |   32 +++++---------------------------
 ./include/linux/raid/raid5.h |    1 -
 2 files changed, 5 insertions(+), 28 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:22:03.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:22:04.000000000 +1000
@@ -373,8 +373,6 @@ static unsigned long get_stripe_work(str
 	test_and_ack_op(STRIPE_OP_BIODRAIN, pending);
 	test_and_ack_op(STRIPE_OP_POSTXOR, pending);
 	test_and_ack_op(STRIPE_OP_CHECK, pending);
-	if (test_and_clear_bit(STRIPE_OP_IO, &sh->ops.pending))
-		ack++;
 
 	sh->ops.count -= ack;
 	if (unlikely(sh->ops.count < 0)) {
@@ -399,7 +397,6 @@ static void ops_run_io(struct stripe_hea
 
 	might_sleep();
 
-	set_bit(STRIPE_IO_STARTED, &sh->state);
 	for (i = disks; i--; ) {
 		int rw;
 		struct bio *bi;
@@ -433,6 +430,8 @@ static void ops_run_io(struct stripe_hea
 				test_bit(STRIPE_EXPAND_READY, &sh->state))
 				md_sync_acct(rdev->bdev, STRIPE_SECTORS);
 
+			set_bit(STRIPE_IO_STARTED, &sh->state);
+
 			bi->bi_bdev = rdev->bdev;
 			pr_debug("%s: for %llu schedule op %ld on disc %d\n",
 				__func__, (unsigned long long)sh->sector,
@@ -900,9 +899,6 @@ static void raid5_run_ops(struct stripe_
 	if (test_bit(STRIPE_OP_CHECK, &pending))
 		ops_run_check(sh);
 
-	if (test_bit(STRIPE_OP_IO, &pending))
-		ops_run_io(sh);
-
 	if (overlap_clear)
 		for (i = disks; i--; ) {
 			struct r5dev *dev = &sh->dev[i];
@@ -2013,8 +2009,6 @@ static int __handle_issuing_new_read_req
 			 */
 			set_bit(R5_LOCKED, &dev->flags);
 			set_bit(R5_Wantread, &dev->flags);
-			if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
-				sh->ops.count++;
 			s->locked++;
 			pr_debug("Reading block %d (sync=%d)\n", disk_idx,
 				s->syncing);
@@ -2208,9 +2202,6 @@ static void handle_issuing_new_write_req
 						"%d for r-m-w\n", i);
 					set_bit(R5_LOCKED, &dev->flags);
 					set_bit(R5_Wantread, &dev->flags);
-					if (!test_and_set_bit(
-						STRIPE_OP_IO, &sh->ops.pending))
-						sh->ops.count++;
 					s->locked++;
 				} else {
 					set_bit(STRIPE_DELAYED, &sh->state);
@@ -2234,9 +2225,6 @@ static void handle_issuing_new_write_req
 						"%d for Reconstruct\n", i);
 					set_bit(R5_LOCKED, &dev->flags);
 					set_bit(R5_Wantread, &dev->flags);
-					if (!test_and_set_bit(
-						STRIPE_OP_IO, &sh->ops.pending))
-						sh->ops.count++;
 					s->locked++;
 				} else {
 					set_bit(STRIPE_DELAYED, &sh->state);
@@ -2444,8 +2432,6 @@ static void handle_parity_checks5(raid5_
 
 		set_bit(R5_LOCKED, &dev->flags);
 		set_bit(R5_Wantwrite, &dev->flags);
-		if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
-			sh->ops.count++;
 
 		clear_bit(STRIPE_DEGRADED, &sh->state);
 		s->locked++;
@@ -2801,9 +2787,6 @@ static void handle_stripe5(struct stripe
 				(i == sh->pd_idx || dev->written)) {
 				pr_debug("Writing block %d\n", i);
 				set_bit(R5_Wantwrite, &dev->flags);
-				if (!test_and_set_bit(
-				    STRIPE_OP_IO, &sh->ops.pending))
-					sh->ops.count++;
 				if (prexor)
 					continue;
 				if (!test_bit(R5_Insync, &dev->flags) ||
@@ -2857,16 +2840,12 @@ static void handle_stripe5(struct stripe
 		dev = &sh->dev[s.failed_num];
 		if (!test_bit(R5_ReWrite, &dev->flags)) {
 			set_bit(R5_Wantwrite, &dev->flags);
-			if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
-				sh->ops.count++;
 			set_bit(R5_ReWrite, &dev->flags);
 			set_bit(R5_LOCKED, &dev->flags);
 			s.locked++;
 		} else {
 			/* let's read it back */
 			set_bit(R5_Wantread, &dev->flags);
-			if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
-				sh->ops.count++;
 			set_bit(R5_LOCKED, &dev->flags);
 			s.locked++;
 		}
@@ -2884,13 +2863,10 @@ static void handle_stripe5(struct stripe
 		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.ack);
 		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.complete);
 
-		for (i = conf->raid_disks; i--; ) {
+		for (i = conf->raid_disks; i--; )
 			set_bit(R5_Wantwrite, &sh->dev[i].flags);
 			set_bit(R5_LOCKED, &dev->flags);
 			s.locked++;
-			if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
-				sh->ops.count++;
-		}
 	}
 
 	if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
@@ -2926,6 +2902,8 @@ static void handle_stripe5(struct stripe
 	if (pending)
 		raid5_run_ops(sh, pending);
 
+	ops_run_io(sh);
+
 	return_io(return_bi);
 
 }

diff .prev/include/linux/raid/raid5.h ./include/linux/raid/raid5.h
--- .prev/include/linux/raid/raid5.h	2008-06-27 16:22:03.000000000 +1000
+++ ./include/linux/raid/raid5.h	2008-06-27 16:22:04.000000000 +1000
@@ -263,7 +263,6 @@ struct r6_state {
 #define STRIPE_OP_BIODRAIN	3
 #define STRIPE_OP_POSTXOR	4
 #define STRIPE_OP_CHECK	5
-#define STRIPE_OP_IO		6
 
 /* modifiers to the base operations
  * STRIPE_OP_MOD_REPAIR_PD - compute the parity block and write it back

[PATCH 020 of 29] md: md: kill STRIPE_OP_IO flag

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

The R5_Want{Read,Write} flags already gate i/o.  So, this flag is
superfluous and we can unconditionally call ops_run_io().

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c         |   32 +++++---------------------------
 ./include/linux/raid/raid5.h |    1 -
 2 files changed, 5 insertions(+), 28 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:22:03.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:22:04.000000000 +1000
@@ -373,8 +373,6 @@ static unsigned long get_stripe_work(str
 	test_and_ack_op(STRIPE_OP_BIODRAIN, pending);
 	test_and_ack_op(STRIPE_OP_POSTXOR, pending);
 	test_and_ack_op(STRIPE_OP_CHECK, pending);
-	if (test_and_clear_bit(STRIPE_OP_IO, &sh->ops.pending))
-		ack++;
 
 	sh->ops.count -= ack;
 	if (unlikely(sh->ops.count < 0)) {
@@ -399,7 +397,6 @@ static void ops_run_io(struct stripe_hea
 
 	might_sleep();
 
-	set_bit(STRIPE_IO_STARTED, &sh->state);
 	for (i = disks; i--; ) {
 		int rw;
 		struct bio *bi;
@@ -433,6 +430,8 @@ static void ops_run_io(struct stripe_hea
 				test_bit(STRIPE_EXPAND_READY, &sh->state))
 				md_sync_acct(rdev->bdev, STRIPE_SECTORS);
 
+			set_bit(STRIPE_IO_STARTED, &sh->state);
+
 			bi->bi_bdev = rdev->bdev;
 			pr_debug("%s: for %llu schedule op %ld on disc %d\n",
 				__func__, (unsigned long long)sh->sector,
@@ -900,9 +899,6 @@ static void raid5_run_ops(struct stripe_
 	if (test_bit(STRIPE_OP_CHECK, &pending))
 		ops_run_check(sh);
 
-	if (test_bit(STRIPE_OP_IO, &pending))
-		ops_run_io(sh);
-
 	if (overlap_clear)
 		for (i = disks; i--; ) {
 			struct r5dev *dev = &sh->dev[i];
@@ -2013,8 +2009,6 @@ static int __handle_issuing_new_read_req
 			 */
 			set_bit(R5_LOCKED, &dev->flags);
 			set_bit(R5_Wantread, &dev->flags);
-			if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
-				sh->ops.count++;
 			s->locked++;
 			pr_debug("Reading block %d (sync=%d)\n", disk_idx,
 				s->syncing);
@@ -2208,9 +2202,6 @@ static void handle_issuing_new_write_req
 						"%d for r-m-w\n", i);
 					set_bit(R5_LOCKED, &dev->flags);
 					set_bit(R5_Wantread, &dev->flags);
-					if (!test_and_set_bit(
-						STRIPE_OP_IO, &sh->ops.pending))
-						sh->ops.count++;
 					s->locked++;
 				} else {
 					set_bit(STRIPE_DELAYED, &sh->state);
@@ -2234,9 +2225,6 @@ static void handle_issuing_new_write_req
 						"%d for Reconstruct\n", i);
 					set_bit(R5_LOCKED, &dev->flags);
 					set_bit(R5_Wantread, &dev->flags);
-					if (!test_and_set_bit(
-						STRIPE_OP_IO, &sh->ops.pending))
-						sh->ops.count++;
 					s->locked++;
 				} else {
 					set_bit(STRIPE_DELAYED, &sh->state);
@@ -2444,8 +2432,6 @@ static void handle_parity_checks5(raid5_
 
 		set_bit(R5_LOCKED, &dev->flags);
 		set_bit(R5_Wantwrite, &dev->flags);
-		if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
-			sh->ops.count++;
 
 		clear_bit(STRIPE_DEGRADED, &sh->state);
 		s->locked++;
@@ -2801,9 +2787,6 @@ static void handle_stripe5(struct stripe
 				(i == sh->pd_idx || dev->written)) {
 				pr_debug("Writing block %d\n", i);
 				set_bit(R5_Wantwrite, &dev->flags);
-				if (!test_and_set_bit(
-				    STRIPE_OP_IO, &sh->ops.pending))
-					sh->ops.count++;
 				if (prexor)
 					continue;
 				if (!test_bit(R5_Insync, &dev->flags) ||
@@ -2857,16 +2840,12 @@ static void handle_stripe5(struct stripe
 		dev = &sh->dev[s.failed_num];
 		if (!test_bit(R5_ReWrite, &dev->flags)) {
 			set_bit(R5_Wantwrite, &dev->flags);
-			if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
-				sh->ops.count++;
 			set_bit(R5_ReWrite, &dev->flags);
 			set_bit(R5_LOCKED, &dev->flags);
 			s.locked++;
 		} else {
 			/* let's read it back */
 			set_bit(R5_Wantread, &dev->flags);
-			if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
-				sh->ops.count++;
 			set_bit(R5_LOCKED, &dev->flags);
 			s.locked++;
 		}
@@ -2884,13 +2863,10 @@ static void handle_stripe5(struct stripe
 		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.ack);
 		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.complete);
 
-		for (i = conf->raid_disks; i--; ) {
+		for (i = conf->raid_disks; i--; )
 			set_bit(R5_Wantwrite, &sh->dev[i].flags);
 			set_bit(R5_LOCKED, &dev->flags);
 			s.locked++;
-			if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
-				sh->ops.count++;
-		}
 	}
 
 	if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
@@ -2926,6 +2902,8 @@ static void handle_stripe5(struct stripe
 	if (pending)
 		raid5_run_ops(sh, pending);
 
+	ops_run_io(sh);
+
 	return_io(return_bi);
 
 }

diff .prev/include/linux/raid/raid5.h ./include/linux/raid/raid5.h
--- .prev/include/linux/raid/raid5.h	2008-06-27 16:22:03.000000000 +1000
+++ ./include/linux/raid/raid5.h	2008-06-27 16:22:04.000000000 +1000
@@ -263,7 +263,6 @@ struct r6_state {
 #define STRIPE_OP_BIODRAIN	3
 #define STRIPE_OP_POSTXOR	4
 #define STRIPE_OP_CHECK	5
-#define STRIPE_OP_IO		6
 
 /* modifiers to the base operations
  * STRIPE_OP_MOD_REPAIR_PD - compute the parity block and write it back

[PATCH 021 of 29] md: md: use stripe_head_state in ops_run_io()

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

In handle_stripe after taking sh->lock we sample some bits into 's' (struct
stripe_head_state):

	s.syncing = test_bit(STRIPE_SYNCING, &sh->state);
	s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
	s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);

Use these values from 's' in ops_run_io() rather than re-sampling the bits.
This ensures a consistent snapshot (as seen under sh->lock) is used.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c |    9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:22:04.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:22:04.000000000 +1000
@@ -390,7 +390,7 @@ raid5_end_read_request(struct bio *bi, i
 static void
 raid5_end_write_request(struct bio *bi, int error);
 
-static void ops_run_io(struct stripe_head *sh)
+static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 {
 	raid5_conf_t *conf = sh->raid_conf;
 	int i, disks = sh->disks;
@@ -425,9 +425,7 @@ static void ops_run_io(struct stripe_hea
 		rcu_read_unlock();
 
 		if (rdev) {
-			if (test_bit(STRIPE_SYNCING, &sh->state) ||
-				test_bit(STRIPE_EXPAND_SOURCE, &sh->state) ||
-				test_bit(STRIPE_EXPAND_READY, &sh->state))
+			if (s->syncing || s->expanding || s->expanded)
 				md_sync_acct(rdev->bdev, STRIPE_SECTORS);
 
 			set_bit(STRIPE_IO_STARTED, &sh->state);
@@ -2902,10 +2900,9 @@ static void handle_stripe5(struct stripe
 	if (pending)
 		raid5_run_ops(sh, pending);
 
-	ops_run_io(sh);
+	ops_run_io(sh, &s);
 
 	return_io(return_bi);
-
 }
 
 static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)

[PATCH 021 of 29] md: md: use stripe_head_state in ops_run_io()

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

In handle_stripe after taking sh->lock we sample some bits into 's' (struct
stripe_head_state):

	s.syncing = test_bit(STRIPE_SYNCING, &sh->state);
	s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
	s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);

Use these values from 's' in ops_run_io() rather than re-sampling the bits.
This ensures a consistent snapshot (as seen under sh->lock) is used.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c |    9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:22:04.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:22:04.000000000 +1000
@@ -390,7 +390,7 @@ raid5_end_read_request(struct bio *bi, i
 static void
 raid5_end_write_request(struct bio *bi, int error);
 
-static void ops_run_io(struct stripe_head *sh)
+static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 {
 	raid5_conf_t *conf = sh->raid_conf;
 	int i, disks = sh->disks;
@@ -425,9 +425,7 @@ static void ops_run_io(struct stripe_hea
 		rcu_read_unlock();
 
 		if (rdev) {
-			if (test_bit(STRIPE_SYNCING, &sh->state) ||
-				test_bit(STRIPE_EXPAND_SOURCE, &sh->state) ||
-				test_bit(STRIPE_EXPAND_READY, &sh->state))
+			if (s->syncing || s->expanding || s->expanded)
 				md_sync_acct(rdev->bdev, STRIPE_SECTORS);
 
 			set_bit(STRIPE_IO_STARTED, &sh->state);
@@ -2902,10 +2900,9 @@ static void handle_stripe5(struct stripe
 	if (pending)
 		raid5_run_ops(sh, pending);
 
-	ops_run_io(sh);
+	ops_run_io(sh, &s);
 
 	return_io(return_bi);
-
 }
 
 static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)

[PATCH 022 of 29] md: md: unify raid5/6 i/o submission

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

Let the raid6 path call ops_run_io to get pending i/o submitted.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c |   63 +--------------------------------------------------
 1 file changed, 2 insertions(+), 61 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:22:04.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:22:05.000000000 +1000
@@ -3114,68 +3114,9 @@ static void handle_stripe6(struct stripe
 	if (unlikely(blocked_rdev))
 		md_wait_for_blocked_rdev(blocked_rdev, conf->mddev);
 
-	return_io(return_bi);
-
-	for (i=disks; i-- ;) {
-		int rw;
-		struct bio *bi;
-		mdk_rdev_t *rdev;
-		if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags))
-			rw = WRITE;
-		else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
-			rw = READ;
-		else
-			continue;
-
-		set_bit(STRIPE_IO_STARTED, &sh->state);
-
-		bi = &sh->dev[i].req;
-
-		bi->bi_rw = rw;
-		if (rw == WRITE)
-			bi->bi_end_io = raid5_end_write_request;
-		else
-			bi->bi_end_io = raid5_end_read_request;
+	ops_run_io(sh, &s);
 
-		rcu_read_lock();
-		rdev = rcu_dereference(conf->disks[i].rdev);
-		if (rdev && test_bit(Faulty, &rdev->flags))
-			rdev = NULL;
-		if (rdev)
-			atomic_inc(&rdev->nr_pending);
-		rcu_read_unlock();
-
-		if (rdev) {
-			if (s.syncing || s.expanding || s.expanded)
-				md_sync_acct(rdev->bdev, STRIPE_SECTORS);
-
-			bi->bi_bdev = rdev->bdev;
-			pr_debug("for %llu schedule op %ld on disc %d\n",
-				(unsigned long long)sh->sector, bi->bi_rw, i);
-			atomic_inc(&sh->count);
-			bi->bi_sector = sh->sector + rdev->data_offset;
-			bi->bi_flags = 1 << BIO_UPTODATE;
-			bi->bi_vcnt = 1;
-			bi->bi_max_vecs = 1;
-			bi->bi_idx = 0;
-			bi->bi_io_vec = &sh->dev[i].vec;
-			bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
-			bi->bi_io_vec[0].bv_offset = 0;
-			bi->bi_size = STRIPE_SIZE;
-			bi->bi_next = NULL;
-			if (rw == WRITE &&
-			    test_bit(R5_ReWrite, &sh->dev[i].flags))
-				atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
-			generic_make_request(bi);
-		} else {
-			if (rw == WRITE)
-				set_bit(STRIPE_DEGRADED, &sh->state);
-			pr_debug("skip op %ld on disc %d for sector %llu\n",
-				bi->bi_rw, i, (unsigned long long)sh->sector);
-			clear_bit(R5_LOCKED, &sh->dev[i].flags);
-			set_bit(STRIPE_HANDLE, &sh->state);
-		}
-	}
+	return_io(return_bi);
 }
 
 static void handle_stripe(struct stripe_head *sh, struct page *tmp_page)

[PATCH 022 of 29] md: md: unify raid5/6 i/o submission

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

Let the raid6 path call ops_run_io to get pending i/o submitted.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c |   63 +--------------------------------------------------
 1 file changed, 2 insertions(+), 61 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:22:04.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:22:05.000000000 +1000
@@ -3114,68 +3114,9 @@ static void handle_stripe6(struct stripe
 	if (unlikely(blocked_rdev))
 		md_wait_for_blocked_rdev(blocked_rdev, conf->mddev);
 
-	return_io(return_bi);
-
-	for (i=disks; i-- ;) {
-		int rw;
-		struct bio *bi;
-		mdk_rdev_t *rdev;
-		if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags))
-			rw = WRITE;
-		else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
-			rw = READ;
-		else
-			continue;
-
-		set_bit(STRIPE_IO_STARTED, &sh->state);
-
-		bi = &sh->dev[i].req;
-
-		bi->bi_rw = rw;
-		if (rw == WRITE)
-			bi->bi_end_io = raid5_end_write_request;
-		else
-			bi->bi_end_io = raid5_end_read_request;
+	ops_run_io(sh, &s);
 
-		rcu_read_lock();
-		rdev = rcu_dereference(conf->disks[i].rdev);
-		if (rdev && test_bit(Faulty, &rdev->flags))
-			rdev = NULL;
-		if (rdev)
-			atomic_inc(&rdev->nr_pending);
-		rcu_read_unlock();
-
-		if (rdev) {
-			if (s.syncing || s.expanding || s.expanded)
-				md_sync_acct(rdev->bdev, STRIPE_SECTORS);
-
-			bi->bi_bdev = rdev->bdev;
-			pr_debug("for %llu schedule op %ld on disc %d\n",
-				(unsigned long long)sh->sector, bi->bi_rw, i);
-			atomic_inc(&sh->count);
-			bi->bi_sector = sh->sector + rdev->data_offset;
-			bi->bi_flags = 1 << BIO_UPTODATE;
-			bi->bi_vcnt = 1;
-			bi->bi_max_vecs = 1;
-			bi->bi_idx = 0;
-			bi->bi_io_vec = &sh->dev[i].vec;
-			bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
-			bi->bi_io_vec[0].bv_offset = 0;
-			bi->bi_size = STRIPE_SIZE;
-			bi->bi_next = NULL;
-			if (rw == WRITE &&
-			    test_bit(R5_ReWrite, &sh->dev[i].flags))
-				atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
-			generic_make_request(bi);
-		} else {
-			if (rw == WRITE)
-				set_bit(STRIPE_DEGRADED, &sh->state);
-			pr_debug("skip op %ld on disc %d for sector %llu\n",
-				bi->bi_rw, i, (unsigned long long)sh->sector);
-			clear_bit(R5_LOCKED, &sh->dev[i].flags);
-			set_bit(STRIPE_HANDLE, &sh->state);
-		}
-	}
+	return_io(return_bi);
 }
 
 static void handle_stripe(struct stripe_head *sh, struct page *tmp_page)

[PATCH 023 of 29] md: md: replace STRIPE_OP_CHECK with 'check_states'

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

The STRIPE_OP_* flags record the state of stripe operations which are
performed outside the stripe lock.  Their use in indicating which
operations need to be run is straightforward; however, interpolating what
the next state of the stripe should be based on a given combination of
these flags is not straightforward, and has led to bugs.  An easier to read
implementation with minimal degrees of freedom is needed.

Towards this goal, this patch introduces explicit states to replace what was
previously interpolated from the STRIPE_OP_* flags.  For now this only converts
the handle_parity_checks5 path, removing a user of the
ops.{pending,ack,complete,count} fields of struct stripe_operations.

This conversion also found a remaining issue with the current code.  There is
a small window for a drive to fail between when we schedule a repair and when
the parity calculation for that repair completes.  When this happens we will
writeback to 'failed_num' when we really want to write back to 'pd_idx'.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c         |  170 ++++++++++++++++++++-----------------------
 ./include/linux/raid/raid5.h |   46 ++++++++++-
 2 files changed, 122 insertions(+), 94 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:22:05.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:22:05.000000000 +1000
@@ -605,7 +605,11 @@ static void ops_complete_compute5(void *
 	set_bit(R5_UPTODATE, &tgt->flags);
 	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
 	clear_bit(R5_Wantcompute, &tgt->flags);
-	set_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete);
+	clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
+	if (sh->check_state == check_state_compute_run)
+		sh->check_state = check_state_compute_result;
+	else
+		set_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete);
 	set_bit(STRIPE_HANDLE, &sh->state);
 	release_stripe(sh);
 }
@@ -838,7 +842,7 @@ static void ops_complete_check(void *str
 	pr_debug("%s: stripe %llu\n", __func__,
 		(unsigned long long)sh->sector);
 
-	set_bit(STRIPE_OP_CHECK, &sh->ops.complete);
+	sh->check_state = check_state_check_result;
 	set_bit(STRIPE_HANDLE, &sh->state);
 	release_stripe(sh);
 }
@@ -870,7 +874,8 @@ static void ops_run_check(struct stripe_
 		ops_complete_check, sh);
 }
 
-static void raid5_run_ops(struct stripe_head *sh, unsigned long pending)
+static void raid5_run_ops(struct stripe_head *sh, unsigned long pending,
+			  unsigned long ops_request)
 {
 	int overlap_clear = 0, i, disks = sh->disks;
 	struct dma_async_tx_descriptor *tx = NULL;
@@ -880,7 +885,8 @@ static void raid5_run_ops(struct stripe_
 		overlap_clear++;
 	}
 
-	if (test_bit(STRIPE_OP_COMPUTE_BLK, &pending))
+	if (test_bit(STRIPE_OP_COMPUTE_BLK, &pending) ||
+	    test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request))
 		tx = ops_run_compute5(sh, pending);
 
 	if (test_bit(STRIPE_OP_PREXOR, &pending))
@@ -894,7 +900,7 @@ static void raid5_run_ops(struct stripe_
 	if (test_bit(STRIPE_OP_POSTXOR, &pending))
 		ops_run_postxor(sh, tx, pending);
 
-	if (test_bit(STRIPE_OP_CHECK, &pending))
+	if (test_bit(STRIPE_OP_CHECK, &ops_request))
 		ops_run_check(sh);
 
 	if (overlap_clear)
@@ -1961,8 +1967,7 @@ static int __handle_issuing_new_read_req
 	/* don't schedule compute operations or reads on the parity block while
 	 * a check is in flight
 	 */
-	if ((disk_idx == sh->pd_idx) &&
-	     test_bit(STRIPE_OP_CHECK, &sh->ops.pending))
+	if (disk_idx == sh->pd_idx && sh->check_state)
 		return ~0;
 
 	/* is the data in this block needed, and can we get it? */
@@ -1983,9 +1988,8 @@ static int __handle_issuing_new_read_req
 		 * 3/ We hold off parity block re-reads until check operations
 		 * have quiesced.
 		 */
-		if ((s->uptodate == disks - 1) &&
-		    (s->failed && disk_idx == s->failed_num) &&
-		    !test_bit(STRIPE_OP_CHECK, &sh->ops.pending)) {
+		if ((s->uptodate == disks - 1) && !sh->check_state &&
+		    (s->failed && disk_idx == s->failed_num)) {
 			set_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending);
 			set_bit(R5_Wantcompute, &dev->flags);
 			sh->ops.target = disk_idx;
@@ -2021,12 +2025,8 @@ static void handle_issuing_new_read_requ
 {
 	int i;
 
-	/* Clear completed compute operations.  Parity recovery
-	 * (STRIPE_OP_MOD_REPAIR_PD) implies a write-back which is handled
-	 * later on in this routine
-	 */
-	if (test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete) &&
-		!test_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending)) {
+	/* Clear completed compute operations */
+	if (test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete)) {
 		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete);
 		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.ack);
 		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending);
@@ -2350,90 +2350,85 @@ static void handle_issuing_new_write_req
 static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh,
 				struct stripe_head_state *s, int disks)
 {
-	int canceled_check = 0;
+	struct r5dev *dev = NULL;
 
 	set_bit(STRIPE_HANDLE, &sh->state);
 
-	/* complete a check operation */
-	if (test_and_clear_bit(STRIPE_OP_CHECK, &sh->ops.complete)) {
-		clear_bit(STRIPE_OP_CHECK, &sh->ops.ack);
-		clear_bit(STRIPE_OP_CHECK, &sh->ops.pending);
+	switch (sh->check_state) {
+	case check_state_idle:
+		/* start a new check operation if there are no failures */
 		if (s->failed == 0) {
-			if (sh->ops.zero_sum_result == 0)
-				/* parity is correct (on disc,
-				 * not in buffer any more)
-				 */
-				set_bit(STRIPE_INSYNC, &sh->state);
-			else {
-				conf->mddev->resync_mismatches +=
-					STRIPE_SECTORS;
-				if (test_bit(
-				     MD_RECOVERY_CHECK, &conf->mddev->recovery))
-					/* don't try to repair!! */
-					set_bit(STRIPE_INSYNC, &sh->state);
-				else {
-					set_bit(STRIPE_OP_COMPUTE_BLK,
-						&sh->ops.pending);
-					set_bit(STRIPE_OP_MOD_REPAIR_PD,
-						&sh->ops.pending);
-					set_bit(R5_Wantcompute,
-						&sh->dev[sh->pd_idx].flags);
-					sh->ops.target = sh->pd_idx;
-					sh->ops.count++;
-					s->uptodate++;
-				}
-			}
-		} else
-			canceled_check = 1; /* STRIPE_INSYNC is not set */
-	}
-
-	/* start a new check operation if there are no failures, the stripe is
-	 * not insync, and a repair is not in flight
-	 */
-	if (s->failed == 0 &&
-	    !test_bit(STRIPE_INSYNC, &sh->state) &&
-	    !test_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending)) {
-		if (!test_and_set_bit(STRIPE_OP_CHECK, &sh->ops.pending)) {
 			BUG_ON(s->uptodate != disks);
+			sh->check_state = check_state_run;
+			set_bit(STRIPE_OP_CHECK, &s->ops_request);
 			clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
-			sh->ops.count++;
 			s->uptodate--;
+			break;
 		}
-	}
-
-	/* check if we can clear a parity disk reconstruct */
-	if (test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete) &&
-	    test_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending)) {
-
-		clear_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending);
-		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete);
-		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.ack);
-		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending);
-	}
+		dev = &sh->dev[s->failed_num];
+		/* fall through */
+	case check_state_compute_result:
+		sh->check_state = check_state_idle;
+		if (!dev)
+			dev = &sh->dev[sh->pd_idx];
 
+		/* check that a write has not made the stripe insync */
+		if (test_bit(STRIPE_INSYNC, &sh->state))
+			break;
 
-	/* Wait for check parity and compute block operations to complete
-	 * before write-back.  If a failure occurred while the check operation
-	 * was in flight we need to cycle this stripe through handle_stripe
-	 * since the parity block may not be uptodate
-	 */
-	if (!canceled_check && !test_bit(STRIPE_INSYNC, &sh->state) &&
-	    !test_bit(STRIPE_OP_CHECK, &sh->ops.pending) &&
-	    !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending)) {
-		struct r5dev *dev;
 		/* either failed parity check, or recovery is happening */
-		if (s->failed == 0)
-			s->failed_num = sh->pd_idx;
-		dev = &sh->dev[s->failed_num];
 		BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
 		BUG_ON(s->uptodate != disks);
 
 		set_bit(R5_LOCKED, &dev->flags);
+		s->locked++;
 		set_bit(R5_Wantwrite, &dev->flags);
 
 		clear_bit(STRIPE_DEGRADED, &sh->state);
-		s->locked++;
 		set_bit(STRIPE_INSYNC, &sh->state);
+		break;
+	case check_state_run:
+		break; /* we will be called again upon completion */
+	case check_state_check_result:
+		sh->check_state = check_state_idle;
+
+		/* if a failure occurred during the check operation, leave
+		 * STRIPE_INSYNC not set and let the stripe be handled again
+		 */
+		if (s->failed)
+			break;
+
+		/* handle a successful check operation, if parity is correct
+		 * we are done.  Otherwise update the mismatch count and repair
+		 * parity if !MD_RECOVERY_CHECK
+		 */
+		if (sh->ops.zero_sum_result == 0)
+			/* parity is correct (on disc,
+			 * not in buffer any more)
+			 */
+			set_bit(STRIPE_INSYNC, &sh->state);
+		else {
+			conf->mddev->resync_mismatches += STRIPE_SECTORS;
+			if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
+				/* don't try to repair!! */
+				set_bit(STRIPE_INSYNC, &sh->state);
+			else {
+				sh->check_state = check_state_compute_run;
+				set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
+				set_bit(R5_Wantcompute,
+					&sh->dev[sh->pd_idx].flags);
+				sh->ops.target = sh->pd_idx;
+				s->uptodate++;
+			}
+		}
+		break;
+	case check_state_compute_run:
+		break;
+	default:
+		printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n",
+		       __func__, sh->check_state,
+		       (unsigned long long) sh->sector);
+		BUG();
 	}
 }
 
@@ -2807,7 +2802,7 @@ static void handle_stripe5(struct stripe
 	 *    block.
 	 */
 	if (s.to_write && !test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending) &&
-			  !test_bit(STRIPE_OP_CHECK, &sh->ops.pending))
+	    !sh->check_state)
 		handle_issuing_new_write_requests5(conf, sh, &s, disks);
 
 	/* maybe we need to check and possibly fix the parity for this stripe
@@ -2815,11 +2810,10 @@ static void handle_stripe5(struct stripe
 	 * data is available.  The parity check is held off while parity
 	 * dependent operations are in flight.
 	 */
-	if ((s.syncing && s.locked == 0 &&
+	if (sh->check_state ||
+	    (s.syncing && s.locked == 0 &&
 	     !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending) &&
-	     !test_bit(STRIPE_INSYNC, &sh->state)) ||
-	      test_bit(STRIPE_OP_CHECK, &sh->ops.pending) ||
-	      test_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending))
+	     !test_bit(STRIPE_INSYNC, &sh->state)))
 		handle_parity_checks5(conf, sh, &s, disks);
 
 	if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
@@ -2897,8 +2891,8 @@ static void handle_stripe5(struct stripe
 	if (unlikely(blocked_rdev))
 		md_wait_for_blocked_rdev(blocked_rdev, conf->mddev);
 
-	if (pending)
-		raid5_run_ops(sh, pending);
+	if (pending || s.ops_request)
+		raid5_run_ops(sh, pending, s.ops_request);
 
 	ops_run_io(sh, &s);
 

diff .prev/include/linux/raid/raid5.h ./include/linux/raid/raid5.h
--- .prev/include/linux/raid/raid5.h	2008-06-27 16:22:04.000000000 +1000
+++ ./include/linux/raid/raid5.h	2008-06-27 16:22:05.000000000 +1000
@@ -158,6 +158,41 @@
  *    the compute block completes.
  */
 
+/*
+ * Operations state - intermediate states that are visible outside of sh->lock
+ * In general _idle indicates nothing is running, _run indicates a data
+ * processing operation is active, and _result means the data processing result
+ * is stable and can be acted upon.  For simple operations like biofill and
+ * compute that only have an _idle and _run state they are indicated with
+ * sh->state flags (STRIPE_BIOFILL_RUN and STRIPE_COMPUTE_RUN)
+ */
+/**
+ * enum check_states - handles syncing / repairing a stripe
+ * @check_state_idle - check operations are quiesced
+ * @check_state_run - check operation is running
+ * @check_state_result - set outside lock when check result is valid
+ * @check_state_compute_run - check failed and we are repairing
+ * @check_state_compute_result - set outside lock when compute result is valid
+ */
+enum check_states {
+	check_state_idle = 0,
+	check_state_run, /* parity check */
+	check_state_check_result,
+	check_state_compute_run, /* parity repair */
+	check_state_compute_result,
+};
+
+/**
+ * enum reconstruct_states - handles writing or expanding a stripe
+ */
+enum reconstruct_states {
+	reconstruct_state_idle = 0,
+	reconstruct_state_drain_run,		/* write */
+	reconstruct_state_run,			/* expand */
+	reconstruct_state_drain_result,
+	reconstruct_state_result,
+};
+
 struct stripe_head {
 	struct hlist_node	hash;
 	struct list_head	lru;			/* inactive_list or handle_list */
@@ -169,6 +204,7 @@ struct stripe_head {
 	spinlock_t		lock;
 	int			bm_seq;	/* sequence number for bitmap flushes */
 	int			disks;			/* disks in stripe */
+	enum check_states	check_state;
 	/* stripe_operations
 	 * @pending - pending ops flags (set for request->issue->complete)
 	 * @ack - submitted ops flags (set for issue->complete)
@@ -202,6 +238,7 @@ struct stripe_head_state {
 	int locked, uptodate, to_read, to_write, failed, written;
 	int to_fill, compute, req_compute, non_overwrite;
 	int failed_num;
+	unsigned long ops_request;
 };
 
 /* r6_state - extra state data only relevant to r6 */
@@ -254,8 +291,10 @@ struct r6_state {
 #define	STRIPE_EXPAND_READY	11
 #define	STRIPE_IO_STARTED	12 /* do not count towards 'bypass_count' */
 #define	STRIPE_FULL_WRITE	13 /* all blocks are set to be overwritten */
+#define	STRIPE_BIOFILL_RUN	14
+#define	STRIPE_COMPUTE_RUN	15
 /*
- * Operations flags (in issue order)
+ * Operation request flags
  */
 #define STRIPE_OP_BIOFILL	0
 #define STRIPE_OP_COMPUTE_BLK	1
@@ -264,11 +303,6 @@ struct r6_state {
 #define STRIPE_OP_POSTXOR	4
 #define STRIPE_OP_CHECK	5
 
-/* modifiers to the base operations
- * STRIPE_OP_MOD_REPAIR_PD - compute the parity block and write it back
- */
-#define STRIPE_OP_MOD_REPAIR_PD 7
-
 /*
  * Plugging:
  *

[PATCH 023 of 29] md: md: replace STRIPE_OP_CHECK with 'check_states'

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

The STRIPE_OP_* flags record the state of stripe operations which are
performed outside the stripe lock.  Their use in indicating which
operations need to be run is straightforward; however, interpolating what
the next state of the stripe should be based on a given combination of
these flags is not straightforward, and has led to bugs.  An easier to read
implementation with minimal degrees of freedom is needed.

Towards this goal, this patch introduces explicit states to replace what was
previously interpolated from the STRIPE_OP_* flags.  For now this only converts
the handle_parity_checks5 path, removing a user of the
ops.{pending,ack,complete,count} fields of struct stripe_operations.

This conversion also found a remaining issue with the current code.  There is
a small window for a drive to fail between when we schedule a repair and when
the parity calculation for that repair completes.  When this happens we will
writeback to 'failed_num' when we really want to write back to 'pd_idx'.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c         |  170 ++++++++++++++++++++-----------------------
 ./include/linux/raid/raid5.h |   46 ++++++++++-
 2 files changed, 122 insertions(+), 94 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:22:05.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:22:05.000000000 +1000
@@ -605,7 +605,11 @@ static void ops_complete_compute5(void *
 	set_bit(R5_UPTODATE, &tgt->flags);
 	BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
 	clear_bit(R5_Wantcompute, &tgt->flags);
-	set_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete);
+	clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
+	if (sh->check_state == check_state_compute_run)
+		sh->check_state = check_state_compute_result;
+	else
+		set_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete);
 	set_bit(STRIPE_HANDLE, &sh->state);
 	release_stripe(sh);
 }
@@ -838,7 +842,7 @@ static void ops_complete_check(void *str
 	pr_debug("%s: stripe %llu\n", __func__,
 		(unsigned long long)sh->sector);
 
-	set_bit(STRIPE_OP_CHECK, &sh->ops.complete);
+	sh->check_state = check_state_check_result;
 	set_bit(STRIPE_HANDLE, &sh->state);
 	release_stripe(sh);
 }
@@ -870,7 +874,8 @@ static void ops_run_check(struct stripe_
 		ops_complete_check, sh);
 }
 
-static void raid5_run_ops(struct stripe_head *sh, unsigned long pending)
+static void raid5_run_ops(struct stripe_head *sh, unsigned long pending,
+			  unsigned long ops_request)
 {
 	int overlap_clear = 0, i, disks = sh->disks;
 	struct dma_async_tx_descriptor *tx = NULL;
@@ -880,7 +885,8 @@ static void raid5_run_ops(struct stripe_
 		overlap_clear++;
 	}
 
-	if (test_bit(STRIPE_OP_COMPUTE_BLK, &pending))
+	if (test_bit(STRIPE_OP_COMPUTE_BLK, &pending) ||
+	    test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request))
 		tx = ops_run_compute5(sh, pending);
 
 	if (test_bit(STRIPE_OP_PREXOR, &pending))
@@ -894,7 +900,7 @@ static void raid5_run_ops(struct stripe_
 	if (test_bit(STRIPE_OP_POSTXOR, &pending))
 		ops_run_postxor(sh, tx, pending);
 
-	if (test_bit(STRIPE_OP_CHECK, &pending))
+	if (test_bit(STRIPE_OP_CHECK, &ops_request))
 		ops_run_check(sh);
 
 	if (overlap_clear)
@@ -1961,8 +1967,7 @@ static int __handle_issuing_new_read_req
 	/* don't schedule compute operations or reads on the parity block while
 	 * a check is in flight
 	 */
-	if ((disk_idx == sh->pd_idx) &&
-	     test_bit(STRIPE_OP_CHECK, &sh->ops.pending))
+	if (disk_idx == sh->pd_idx && sh->check_state)
 		return ~0;
 
 	/* is the data in this block needed, and can we get it? */
@@ -1983,9 +1988,8 @@ static int __handle_issuing_new_read_req
 		 * 3/ We hold off parity block re-reads until check operations
 		 * have quiesced.
 		 */
-		if ((s->uptodate == disks - 1) &&
-		    (s->failed && disk_idx == s->failed_num) &&
-		    !test_bit(STRIPE_OP_CHECK, &sh->ops.pending)) {
+		if ((s->uptodate == disks - 1) && !sh->check_state &&
+		    (s->failed && disk_idx == s->failed_num)) {
 			set_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending);
 			set_bit(R5_Wantcompute, &dev->flags);
 			sh->ops.target = disk_idx;
@@ -2021,12 +2025,8 @@ static void handle_issuing_new_read_requ
 {
 	int i;
 
-	/* Clear completed compute operations.  Parity recovery
-	 * (STRIPE_OP_MOD_REPAIR_PD) implies a write-back which is handled
-	 * later on in this routine
-	 */
-	if (test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete) &&
-		!test_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending)) {
+	/* Clear completed compute operations */
+	if (test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete)) {
 		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete);
 		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.ack);
 		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending);
@@ -2350,90 +2350,85 @@ static void handle_issuing_new_write_req
 static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh,
 				struct stripe_head_state *s, int disks)
 {
-	int canceled_check = 0;
+	struct r5dev *dev = NULL;
 
 	set_bit(STRIPE_HANDLE, &sh->state);
 
-	/* complete a check operation */
-	if (test_and_clear_bit(STRIPE_OP_CHECK, &sh->ops.complete)) {
-		clear_bit(STRIPE_OP_CHECK, &sh->ops.ack);
-		clear_bit(STRIPE_OP_CHECK, &sh->ops.pending);
+	switch (sh->check_state) {
+	case check_state_idle:
+		/* start a new check operation if there are no failures */
 		if (s->failed == 0) {
-			if (sh->ops.zero_sum_result == 0)
-				/* parity is correct (on disc,
-				 * not in buffer any more)
-				 */
-				set_bit(STRIPE_INSYNC, &sh->state);
-			else {
-				conf->mddev->resync_mismatches +=
-					STRIPE_SECTORS;
-				if (test_bit(
-				     MD_RECOVERY_CHECK, &conf->mddev->recovery))
-					/* don't try to repair!! */
-					set_bit(STRIPE_INSYNC, &sh->state);
-				else {
-					set_bit(STRIPE_OP_COMPUTE_BLK,
-						&sh->ops.pending);
-					set_bit(STRIPE_OP_MOD_REPAIR_PD,
-						&sh->ops.pending);
-					set_bit(R5_Wantcompute,
-						&sh->dev[sh->pd_idx].flags);
-					sh->ops.target = sh->pd_idx;
-					sh->ops.count++;
-					s->uptodate++;
-				}
-			}
-		} else
-			canceled_check = 1; /* STRIPE_INSYNC is not set */
-	}
-
-	/* start a new check operation if there are no failures, the stripe is
-	 * not insync, and a repair is not in flight
-	 */
-	if (s->failed == 0 &&
-	    !test_bit(STRIPE_INSYNC, &sh->state) &&
-	    !test_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending)) {
-		if (!test_and_set_bit(STRIPE_OP_CHECK, &sh->ops.pending)) {
 			BUG_ON(s->uptodate != disks);
+			sh->check_state = check_state_run;
+			set_bit(STRIPE_OP_CHECK, &s->ops_request);
 			clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
-			sh->ops.count++;
 			s->uptodate--;
+			break;
 		}
-	}
-
-	/* check if we can clear a parity disk reconstruct */
-	if (test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete) &&
-	    test_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending)) {
-
-		clear_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending);
-		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete);
-		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.ack);
-		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending);
-	}
+		dev = &sh->dev[s->failed_num];
+		/* fall through */
+	case check_state_compute_result:
+		sh->check_state = check_state_idle;
+		if (!dev)
+			dev = &sh->dev[sh->pd_idx];
 
+		/* check that a write has not made the stripe insync */
+		if (test_bit(STRIPE_INSYNC, &sh->state))
+			break;
 
-	/* Wait for check parity and compute block operations to complete
-	 * before write-back.  If a failure occurred while the check operation
-	 * was in flight we need to cycle this stripe through handle_stripe
-	 * since the parity block may not be uptodate
-	 */
-	if (!canceled_check && !test_bit(STRIPE_INSYNC, &sh->state) &&
-	    !test_bit(STRIPE_OP_CHECK, &sh->ops.pending) &&
-	    !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending)) {
-		struct r5dev *dev;
 		/* either failed parity check, or recovery is happening */
-		if (s->failed == 0)
-			s->failed_num = sh->pd_idx;
-		dev = &sh->dev[s->failed_num];
 		BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
 		BUG_ON(s->uptodate != disks);
 
 		set_bit(R5_LOCKED, &dev->flags);
+		s->locked++;
 		set_bit(R5_Wantwrite, &dev->flags);
 
 		clear_bit(STRIPE_DEGRADED, &sh->state);
-		s->locked++;
 		set_bit(STRIPE_INSYNC, &sh->state);
+		break;
+	case check_state_run:
+		break; /* we will be called again upon completion */
+	case check_state_check_result:
+		sh->check_state = check_state_idle;
+
+		/* if a failure occurred during the check operation, leave
+		 * STRIPE_INSYNC not set and let the stripe be handled again
+		 */
+		if (s->failed)
+			break;
+
+		/* handle a successful check operation, if parity is correct
+		 * we are done.  Otherwise update the mismatch count and repair
+		 * parity if !MD_RECOVERY_CHECK
+		 */
+		if (sh->ops.zero_sum_result == 0)
+			/* parity is correct (on disc,
+			 * not in buffer any more)
+			 */
+			set_bit(STRIPE_INSYNC, &sh->state);
+		else {
+			conf->mddev->resync_mismatches += STRIPE_SECTORS;
+			if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
+				/* don't try to repair!! */
+				set_bit(STRIPE_INSYNC, &sh->state);
+			else {
+				sh->check_state = check_state_compute_run;
+				set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
+				set_bit(R5_Wantcompute,
+					&sh->dev[sh->pd_idx].flags);
+				sh->ops.target = sh->pd_idx;
+				s->uptodate++;
+			}
+		}
+		break;
+	case check_state_compute_run:
+		break;
+	default:
+		printk(KERN_ERR "%s: unknown check_state: %d sector: %llu\n",
+		       __func__, sh->check_state,
+		       (unsigned long long) sh->sector);
+		BUG();
 	}
 }
 
@@ -2807,7 +2802,7 @@ static void handle_stripe5(struct stripe
 	 *    block.
 	 */
 	if (s.to_write && !test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending) &&
-			  !test_bit(STRIPE_OP_CHECK, &sh->ops.pending))
+	    !sh->check_state)
 		handle_issuing_new_write_requests5(conf, sh, &s, disks);
 
 	/* maybe we need to check and possibly fix the parity for this stripe
@@ -2815,11 +2810,10 @@ static void handle_stripe5(struct stripe
 	 * data is available.  The parity check is held off while parity
 	 * dependent operations are in flight.
 	 */
-	if ((s.syncing && s.locked == 0 &&
+	if (sh->check_state ||
+	    (s.syncing && s.locked == 0 &&
 	     !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending) &&
-	     !test_bit(STRIPE_INSYNC, &sh->state)) ||
-	      test_bit(STRIPE_OP_CHECK, &sh->ops.pending) ||
-	      test_bit(STRIPE_OP_MOD_REPAIR_PD, &sh->ops.pending))
+	     !test_bit(STRIPE_INSYNC, &sh->state)))
 		handle_parity_checks5(conf, sh, &s, disks);
 
 	if (s.syncing && s.locked == 0 && test_bit(STRIPE_INSYNC, &sh->state)) {
@@ -2897,8 +2891,8 @@ static void handle_stripe5(struct stripe
 	if (unlikely(blocked_rdev))
 		md_wait_for_blocked_rdev(blocked_rdev, conf->mddev);
 
-	if (pending)
-		raid5_run_ops(sh, pending);
+	if (pending || s.ops_request)
+		raid5_run_ops(sh, pending, s.ops_request);
 
 	ops_run_io(sh, &s);
 

diff .prev/include/linux/raid/raid5.h ./include/linux/raid/raid5.h
--- .prev/include/linux/raid/raid5.h	2008-06-27 16:22:04.000000000 +1000
+++ ./include/linux/raid/raid5.h	2008-06-27 16:22:05.000000000 +1000
@@ -158,6 +158,41 @@
  *    the compute block completes.
  */
 
+/*
+ * Operations state - intermediate states that are visible outside of sh->lock
+ * In general _idle indicates nothing is running, _run indicates a data
+ * processing operation is active, and _result means the data processing result
+ * is stable and can be acted upon.  For simple operations like biofill and
+ * compute that only have an _idle and _run state they are indicated with
+ * sh->state flags (STRIPE_BIOFILL_RUN and STRIPE_COMPUTE_RUN)
+ */
+/**
+ * enum check_states - handles syncing / repairing a stripe
+ * @check_state_idle - check operations are quiesced
+ * @check_state_run - check operation is running
+ * @check_state_result - set outside lock when check result is valid
+ * @check_state_compute_run - check failed and we are repairing
+ * @check_state_compute_result - set outside lock when compute result is valid
+ */
+enum check_states {
+	check_state_idle = 0,
+	check_state_run, /* parity check */
+	check_state_check_result,
+	check_state_compute_run, /* parity repair */
+	check_state_compute_result,
+};
+
+/**
+ * enum reconstruct_states - handles writing or expanding a stripe
+ */
+enum reconstruct_states {
+	reconstruct_state_idle = 0,
+	reconstruct_state_drain_run,		/* write */
+	reconstruct_state_run,			/* expand */
+	reconstruct_state_drain_result,
+	reconstruct_state_result,
+};
+
 struct stripe_head {
 	struct hlist_node	hash;
 	struct list_head	lru;			/* inactive_list or handle_list */
@@ -169,6 +204,7 @@ struct stripe_head {
 	spinlock_t		lock;
 	int			bm_seq;	/* sequence number for bitmap flushes */
 	int			disks;			/* disks in stripe */
+	enum check_states	check_state;
 	/* stripe_operations
 	 * @pending - pending ops flags (set for request->issue->complete)
 	 * @ack - submitted ops flags (set for issue->complete)
@@ -202,6 +238,7 @@ struct stripe_head_state {
 	int locked, uptodate, to_read, to_write, failed, written;
 	int to_fill, compute, req_compute, non_overwrite;
 	int failed_num;
+	unsigned long ops_request;
 };
 
 /* r6_state - extra state data only relevant to r6 */
@@ -254,8 +291,10 @@ struct r6_state {
 #define	STRIPE_EXPAND_READY	11
 #define	STRIPE_IO_STARTED	12 /* do not count towards 'bypass_count' */
 #define	STRIPE_FULL_WRITE	13 /* all blocks are set to be overwritten */
+#define	STRIPE_BIOFILL_RUN	14
+#define	STRIPE_COMPUTE_RUN	15
 /*
- * Operations flags (in issue order)
+ * Operation request flags
  */
 #define STRIPE_OP_BIOFILL	0
 #define STRIPE_OP_COMPUTE_BLK	1
@@ -264,11 +303,6 @@ struct r6_state {
 #define STRIPE_OP_POSTXOR	4
 #define STRIPE_OP_CHECK	5
 
-/* modifiers to the base operations
- * STRIPE_OP_MOD_REPAIR_PD - compute the parity block and write it back
- */
-#define STRIPE_OP_MOD_REPAIR_PD 7
-
 /*
  * Plugging:
  *

[PATCH 024 of 29] md: md: replace STRIPE_OP_BIOFILL with STRIPE_BIOFILL_RUN

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

Track the state of read operations (copying data from the stripe cache to bio
buffers outside the lock) with a state flag.  Reduce the scope of the
STRIPE_OP_BIOFILL flag to only tracking whether a biofill operation has been
requested via the ops_request field of struct stripe_head_state.

This is another step towards the removal of ops.{pending,ack,complete,count},
i.e. STRIPE_OP_BIOFILL only requests an operation and does not track the state
of the operation.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c |   33 ++++++++++++---------------------
 1 file changed, 12 insertions(+), 21 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:22:05.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:22:05.000000000 +1000
@@ -523,38 +523,34 @@ static void ops_complete_biofill(void *s
 		(unsigned long long)sh->sector);
 
 	/* clear completed biofills */
+	spin_lock_irq(&conf->device_lock);
 	for (i = sh->disks; i--; ) {
 		struct r5dev *dev = &sh->dev[i];
 
 		/* acknowledge completion of a biofill operation */
 		/* and check if we need to reply to a read request,
 		 * new R5_Wantfill requests are held off until
-		 * !test_bit(STRIPE_OP_BIOFILL, &sh->ops.pending)
+		 * !STRIPE_BIOFILL_RUN
 		 */
 		if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
 			struct bio *rbi, *rbi2;
 
-			/* The access to dev->read is outside of the
-			 * spin_lock_irq(&conf->device_lock), but is protected
-			 * by the STRIPE_OP_BIOFILL pending bit
-			 */
 			BUG_ON(!dev->read);
 			rbi = dev->read;
 			dev->read = NULL;
 			while (rbi && rbi->bi_sector <
 				dev->sector + STRIPE_SECTORS) {
 				rbi2 = r5_next_bio(rbi, dev->sector);
-				spin_lock_irq(&conf->device_lock);
 				if (--rbi->bi_phys_segments == 0) {
 					rbi->bi_next = return_bi;
 					return_bi = rbi;
 				}
-				spin_unlock_irq(&conf->device_lock);
 				rbi = rbi2;
 			}
 		}
 	}
-	set_bit(STRIPE_OP_BIOFILL, &sh->ops.complete);
+	spin_unlock_irq(&conf->device_lock);
+	clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
 
 	return_io(return_bi);
 
@@ -880,7 +876,7 @@ static void raid5_run_ops(struct stripe_
 	int overlap_clear = 0, i, disks = sh->disks;
 	struct dma_async_tx_descriptor *tx = NULL;
 
-	if (test_bit(STRIPE_OP_BIOFILL, &pending)) {
+	if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
 		ops_run_biofill(sh);
 		overlap_clear++;
 	}
@@ -2630,15 +2626,8 @@ static void handle_stripe5(struct stripe
 	s.syncing = test_bit(STRIPE_SYNCING, &sh->state);
 	s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
 	s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
-	/* Now to look around and see what can be done */
-
-	/* clean-up completed biofill operations */
-	if (test_bit(STRIPE_OP_BIOFILL, &sh->ops.complete)) {
-		clear_bit(STRIPE_OP_BIOFILL, &sh->ops.pending);
-		clear_bit(STRIPE_OP_BIOFILL, &sh->ops.ack);
-		clear_bit(STRIPE_OP_BIOFILL, &sh->ops.complete);
-	}
 
+	/* Now to look around and see what can be done */
 	rcu_read_lock();
 	for (i=disks; i--; ) {
 		mdk_rdev_t *rdev;
@@ -2652,10 +2641,10 @@ static void handle_stripe5(struct stripe
 		/* maybe we can request a biofill operation
 		 *
 		 * new wantfill requests are only permitted while
-		 * STRIPE_OP_BIOFILL is clear
+		 * ops_complete_biofill is guaranteed to be inactive
 		 */
 		if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
-			!test_bit(STRIPE_OP_BIOFILL, &sh->ops.pending))
+		    !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
 			set_bit(R5_Wantfill, &dev->flags);
 
 		/* now count some things */
@@ -2699,8 +2688,10 @@ static void handle_stripe5(struct stripe
 		goto unlock;
 	}
 
-	if (s.to_fill && !test_and_set_bit(STRIPE_OP_BIOFILL, &sh->ops.pending))
-		sh->ops.count++;
+	if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
+		set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
+		set_bit(STRIPE_BIOFILL_RUN, &sh->state);
+	}
 
 	pr_debug("locked=%d uptodate=%d to_read=%d"
 		" to_write=%d failed=%d failed_num=%d\n",

[PATCH 024 of 29] md: md: replace STRIPE_OP_BIOFILL with STRIPE_BIOFILL_RUN

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

Track the state of read operations (copying data from the stripe cache to bio
buffers outside the lock) with a state flag.  Reduce the scope of the
STRIPE_OP_BIOFILL flag to only tracking whether a biofill operation has been
requested via the ops_request field of struct stripe_head_state.

This is another step towards the removal of ops.{pending,ack,complete,count},
i.e. STRIPE_OP_BIOFILL only requests an operation and does not track the state
of the operation.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c |   33 ++++++++++++---------------------
 1 file changed, 12 insertions(+), 21 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:22:05.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:22:05.000000000 +1000
@@ -523,38 +523,34 @@ static void ops_complete_biofill(void *s
 		(unsigned long long)sh->sector);
 
 	/* clear completed biofills */
+	spin_lock_irq(&conf->device_lock);
 	for (i = sh->disks; i--; ) {
 		struct r5dev *dev = &sh->dev[i];
 
 		/* acknowledge completion of a biofill operation */
 		/* and check if we need to reply to a read request,
 		 * new R5_Wantfill requests are held off until
-		 * !test_bit(STRIPE_OP_BIOFILL, &sh->ops.pending)
+		 * !STRIPE_BIOFILL_RUN
 		 */
 		if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
 			struct bio *rbi, *rbi2;
 
-			/* The access to dev->read is outside of the
-			 * spin_lock_irq(&conf->device_lock), but is protected
-			 * by the STRIPE_OP_BIOFILL pending bit
-			 */
 			BUG_ON(!dev->read);
 			rbi = dev->read;
 			dev->read = NULL;
 			while (rbi && rbi->bi_sector <
 				dev->sector + STRIPE_SECTORS) {
 				rbi2 = r5_next_bio(rbi, dev->sector);
-				spin_lock_irq(&conf->device_lock);
 				if (--rbi->bi_phys_segments == 0) {
 					rbi->bi_next = return_bi;
 					return_bi = rbi;
 				}
-				spin_unlock_irq(&conf->device_lock);
 				rbi = rbi2;
 			}
 		}
 	}
-	set_bit(STRIPE_OP_BIOFILL, &sh->ops.complete);
+	spin_unlock_irq(&conf->device_lock);
+	clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
 
 	return_io(return_bi);
 
@@ -880,7 +876,7 @@ static void raid5_run_ops(struct stripe_
 	int overlap_clear = 0, i, disks = sh->disks;
 	struct dma_async_tx_descriptor *tx = NULL;
 
-	if (test_bit(STRIPE_OP_BIOFILL, &pending)) {
+	if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
 		ops_run_biofill(sh);
 		overlap_clear++;
 	}
@@ -2630,15 +2626,8 @@ static void handle_stripe5(struct stripe
 	s.syncing = test_bit(STRIPE_SYNCING, &sh->state);
 	s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
 	s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
-	/* Now to look around and see what can be done */
-
-	/* clean-up completed biofill operations */
-	if (test_bit(STRIPE_OP_BIOFILL, &sh->ops.complete)) {
-		clear_bit(STRIPE_OP_BIOFILL, &sh->ops.pending);
-		clear_bit(STRIPE_OP_BIOFILL, &sh->ops.ack);
-		clear_bit(STRIPE_OP_BIOFILL, &sh->ops.complete);
-	}
 
+	/* Now to look around and see what can be done */
 	rcu_read_lock();
 	for (i=disks; i--; ) {
 		mdk_rdev_t *rdev;
@@ -2652,10 +2641,10 @@ static void handle_stripe5(struct stripe
 		/* maybe we can request a biofill operation
 		 *
 		 * new wantfill requests are only permitted while
-		 * STRIPE_OP_BIOFILL is clear
+		 * ops_complete_biofill is guaranteed to be inactive
 		 */
 		if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
-			!test_bit(STRIPE_OP_BIOFILL, &sh->ops.pending))
+		    !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
 			set_bit(R5_Wantfill, &dev->flags);
 
 		/* now count some things */
@@ -2699,8 +2688,10 @@ static void handle_stripe5(struct stripe
 		goto unlock;
 	}
 
-	if (s.to_fill && !test_and_set_bit(STRIPE_OP_BIOFILL, &sh->ops.pending))
-		sh->ops.count++;
+	if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
+		set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
+		set_bit(STRIPE_BIOFILL_RUN, &sh->state);
+	}
 
 	pr_debug("locked=%d uptodate=%d to_read=%d"
 		" to_write=%d failed=%d failed_num=%d\n",

[PATCH 025 of 29] md: md: replace STRIPE_OP_COMPUTE_BLK with STRIPE_COMPUTE_RUN

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

Track the state of compute operations (recalculating a block from all the other
blocks in a stripe) with a state flag.  Reduces the scope of the
STRIPE_OP_COMPUTE_BLK flag to only tracking whether a compute operation has
been requested via the ops_request field of struct stripe_head_state.

Note, the compute operation that is performed in the course of doing a 'repair'
operation (check the parity block, recalculate it and write it back if the
check result is not zero) is tracked separately with the 'check_state'
variable.  Compute operations are held off while a 'check' is in progress, and
moving this check out to handle_issuing_new_read_requests5 the helper routine
__handle_issuing_new_read_requests5 can be simplified.

This is another step towards the removal of ops.{pending,ack,complete,count},
i.e. STRIPE_OP_COMPUTE_BLK only requests an operation and does not track the
state of the operation.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c |   65 ++++++++++++++-------------------------------------
 1 file changed, 18 insertions(+), 47 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:22:05.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:22:06.000000000 +1000
@@ -604,8 +604,6 @@ static void ops_complete_compute5(void *
 	clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
 	if (sh->check_state == check_state_compute_run)
 		sh->check_state = check_state_compute_result;
-	else
-		set_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete);
 	set_bit(STRIPE_HANDLE, &sh->state);
 	release_stripe(sh);
 }
@@ -881,8 +879,7 @@ static void raid5_run_ops(struct stripe_
 		overlap_clear++;
 	}
 
-	if (test_bit(STRIPE_OP_COMPUTE_BLK, &pending) ||
-	    test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request))
+	if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request))
 		tx = ops_run_compute5(sh, pending);
 
 	if (test_bit(STRIPE_OP_PREXOR, &pending))
@@ -1960,12 +1957,6 @@ static int __handle_issuing_new_read_req
 	struct r5dev *dev = &sh->dev[disk_idx];
 	struct r5dev *failed_dev = &sh->dev[s->failed_num];
 
-	/* don't schedule compute operations or reads on the parity block while
-	 * a check is in flight
-	 */
-	if (disk_idx == sh->pd_idx && sh->check_state)
-		return ~0;
-
 	/* is the data in this block needed, and can we get it? */
 	if (!test_bit(R5_LOCKED, &dev->flags) &&
 	    !test_bit(R5_UPTODATE, &dev->flags) && (dev->toread ||
@@ -1974,23 +1965,16 @@ static int __handle_issuing_new_read_req
 	     (failed_dev->toread || (failed_dev->towrite &&
 	     !test_bit(R5_OVERWRITE, &failed_dev->flags)
 	     ))))) {
-		/* 1/ We would like to get this block, possibly by computing it,
-		 * but we might not be able to.
-		 *
-		 * 2/ Since parity check operations potentially make the parity
-		 * block !uptodate it will need to be refreshed before any
-		 * compute operations on data disks are scheduled.
-		 *
-		 * 3/ We hold off parity block re-reads until check operations
-		 * have quiesced.
+		/* We would like to get this block, possibly by computing it,
+		 * otherwise read it if the backing disk is insync
 		 */
-		if ((s->uptodate == disks - 1) && !sh->check_state &&
+		if ((s->uptodate == disks - 1) &&
 		    (s->failed && disk_idx == s->failed_num)) {
-			set_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending);
+			set_bit(STRIPE_COMPUTE_RUN, &sh->state);
+			set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
 			set_bit(R5_Wantcompute, &dev->flags);
 			sh->ops.target = disk_idx;
 			s->req_compute = 1;
-			sh->ops.count++;
 			/* Careful: from this point on 'uptodate' is in the eye
 			 * of raid5_run_ops which services 'compute' operations
 			 * before writes. R5_Wantcompute flags a block that will
@@ -1999,12 +1983,7 @@ static int __handle_issuing_new_read_req
 			 */
 			s->uptodate++;
 			return 0; /* uptodate + compute == disks */
-		} else if ((s->uptodate < disks - 1) &&
-			test_bit(R5_Insync, &dev->flags)) {
-			/* Note: we hold off compute operations while checks are
-			 * in flight, but we still prefer 'compute' over 'read'
-			 * hence we only read if (uptodate < * disks-1)
-			 */
+		} else if (test_bit(R5_Insync, &dev->flags)) {
 			set_bit(R5_LOCKED, &dev->flags);
 			set_bit(R5_Wantread, &dev->flags);
 			s->locked++;
@@ -2021,20 +2000,13 @@ static void handle_issuing_new_read_requ
 {
 	int i;
 
-	/* Clear completed compute operations */
-	if (test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete)) {
-		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete);
-		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.ack);
-		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending);
-	}
-
 	/* look for blocks to read/compute, skip this if a compute
 	 * is already in flight, or if the stripe contents are in the
 	 * midst of changing due to a write
 	 */
-	if (!test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending) &&
-		!test_bit(STRIPE_OP_PREXOR, &sh->ops.pending) &&
-		!test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
+	if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
+	    !test_bit(STRIPE_OP_PREXOR, &sh->ops.pending) &&
+	    !test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
 		for (i = disks; i--; )
 			if (__handle_issuing_new_read_requests5(
 				sh, s, i, disks) == 0)
@@ -2236,10 +2208,9 @@ static void handle_issuing_new_write_req
 	 * simultaneously.  If this is not the case then new writes need to be
 	 * held off until the compute completes.
 	 */
-	if ((s->req_compute ||
-	    !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending)) &&
-		(s->locked == 0 && (rcw == 0 || rmw == 0) &&
-		!test_bit(STRIPE_BIT_DELAY, &sh->state)))
+	if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
+	    (s->locked == 0 && (rcw == 0 || rmw == 0) &&
+	    !test_bit(STRIPE_BIT_DELAY, &sh->state)))
 		s->locked += handle_write_operations5(sh, rcw == 0, 0);
 }
 
@@ -2410,6 +2381,7 @@ static void handle_parity_checks5(raid5_
 				set_bit(STRIPE_INSYNC, &sh->state);
 			else {
 				sh->check_state = check_state_compute_run;
+				set_bit(STRIPE_COMPUTE_RUN, &sh->state);
 				set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
 				set_bit(R5_Wantcompute,
 					&sh->dev[sh->pd_idx].flags);
@@ -2725,8 +2697,7 @@ static void handle_stripe5(struct stripe
 	 * or to load a block that is being partially written.
 	 */
 	if (s.to_read || s.non_overwrite ||
-	    (s.syncing && (s.uptodate + s.compute < disks)) || s.expanding ||
-	    test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending))
+	    (s.syncing && (s.uptodate + s.compute < disks)) || s.expanding)
 		handle_issuing_new_read_requests5(sh, &s, disks);
 
 	/* Now we check to see if any write operations have recently
@@ -2803,7 +2774,7 @@ static void handle_stripe5(struct stripe
 	 */
 	if (sh->check_state ||
 	    (s.syncing && s.locked == 0 &&
-	     !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending) &&
+	     !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
 	     !test_bit(STRIPE_INSYNC, &sh->state)))
 		handle_parity_checks5(conf, sh, &s, disks);
 
@@ -2869,7 +2840,7 @@ static void handle_stripe5(struct stripe
 	}
 
 	if (s.expanding && s.locked == 0 &&
-	    !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending))
+	    !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
 		handle_stripe_expansion(conf, sh, NULL);
 
 	if (sh->ops.count)
@@ -3089,7 +3060,7 @@ static void handle_stripe6(struct stripe
 	}
 
 	if (s.expanding && s.locked == 0 &&
-	    !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending))
+	    !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
 		handle_stripe_expansion(conf, sh, &r6s);
 
  unlock:

[PATCH 025 of 29] md: md: replace STRIPE_OP_COMPUTE_BLK with STRIPE_COMPUTE_RUN

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

Track the state of compute operations (recalculating a block from all the other
blocks in a stripe) with a state flag.  Reduces the scope of the
STRIPE_OP_COMPUTE_BLK flag to only tracking whether a compute operation has
been requested via the ops_request field of struct stripe_head_state.

Note, the compute operation that is performed in the course of doing a 'repair'
operation (check the parity block, recalculate it and write it back if the
check result is not zero) is tracked separately with the 'check_state'
variable.  Compute operations are held off while a 'check' is in progress, and
moving this check out to handle_issuing_new_read_requests5 the helper routine
__handle_issuing_new_read_requests5 can be simplified.

This is another step towards the removal of ops.{pending,ack,complete,count},
i.e. STRIPE_OP_COMPUTE_BLK only requests an operation and does not track the
state of the operation.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c |   65 ++++++++++++++-------------------------------------
 1 file changed, 18 insertions(+), 47 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:22:05.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:22:06.000000000 +1000
@@ -604,8 +604,6 @@ static void ops_complete_compute5(void *
 	clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
 	if (sh->check_state == check_state_compute_run)
 		sh->check_state = check_state_compute_result;
-	else
-		set_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete);
 	set_bit(STRIPE_HANDLE, &sh->state);
 	release_stripe(sh);
 }
@@ -881,8 +879,7 @@ static void raid5_run_ops(struct stripe_
 		overlap_clear++;
 	}
 
-	if (test_bit(STRIPE_OP_COMPUTE_BLK, &pending) ||
-	    test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request))
+	if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request))
 		tx = ops_run_compute5(sh, pending);
 
 	if (test_bit(STRIPE_OP_PREXOR, &pending))
@@ -1960,12 +1957,6 @@ static int __handle_issuing_new_read_req
 	struct r5dev *dev = &sh->dev[disk_idx];
 	struct r5dev *failed_dev = &sh->dev[s->failed_num];
 
-	/* don't schedule compute operations or reads on the parity block while
-	 * a check is in flight
-	 */
-	if (disk_idx == sh->pd_idx && sh->check_state)
-		return ~0;
-
 	/* is the data in this block needed, and can we get it? */
 	if (!test_bit(R5_LOCKED, &dev->flags) &&
 	    !test_bit(R5_UPTODATE, &dev->flags) && (dev->toread ||
@@ -1974,23 +1965,16 @@ static int __handle_issuing_new_read_req
 	     (failed_dev->toread || (failed_dev->towrite &&
 	     !test_bit(R5_OVERWRITE, &failed_dev->flags)
 	     ))))) {
-		/* 1/ We would like to get this block, possibly by computing it,
-		 * but we might not be able to.
-		 *
-		 * 2/ Since parity check operations potentially make the parity
-		 * block !uptodate it will need to be refreshed before any
-		 * compute operations on data disks are scheduled.
-		 *
-		 * 3/ We hold off parity block re-reads until check operations
-		 * have quiesced.
+		/* We would like to get this block, possibly by computing it,
+		 * otherwise read it if the backing disk is insync
 		 */
-		if ((s->uptodate == disks - 1) && !sh->check_state &&
+		if ((s->uptodate == disks - 1) &&
 		    (s->failed && disk_idx == s->failed_num)) {
-			set_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending);
+			set_bit(STRIPE_COMPUTE_RUN, &sh->state);
+			set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
 			set_bit(R5_Wantcompute, &dev->flags);
 			sh->ops.target = disk_idx;
 			s->req_compute = 1;
-			sh->ops.count++;
 			/* Careful: from this point on 'uptodate' is in the eye
 			 * of raid5_run_ops which services 'compute' operations
 			 * before writes. R5_Wantcompute flags a block that will
@@ -1999,12 +1983,7 @@ static int __handle_issuing_new_read_req
 			 */
 			s->uptodate++;
 			return 0; /* uptodate + compute == disks */
-		} else if ((s->uptodate < disks - 1) &&
-			test_bit(R5_Insync, &dev->flags)) {
-			/* Note: we hold off compute operations while checks are
-			 * in flight, but we still prefer 'compute' over 'read'
-			 * hence we only read if (uptodate < * disks-1)
-			 */
+		} else if (test_bit(R5_Insync, &dev->flags)) {
 			set_bit(R5_LOCKED, &dev->flags);
 			set_bit(R5_Wantread, &dev->flags);
 			s->locked++;
@@ -2021,20 +2000,13 @@ static void handle_issuing_new_read_requ
 {
 	int i;
 
-	/* Clear completed compute operations */
-	if (test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete)) {
-		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.complete);
-		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.ack);
-		clear_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending);
-	}
-
 	/* look for blocks to read/compute, skip this if a compute
 	 * is already in flight, or if the stripe contents are in the
 	 * midst of changing due to a write
 	 */
-	if (!test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending) &&
-		!test_bit(STRIPE_OP_PREXOR, &sh->ops.pending) &&
-		!test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
+	if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
+	    !test_bit(STRIPE_OP_PREXOR, &sh->ops.pending) &&
+	    !test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
 		for (i = disks; i--; )
 			if (__handle_issuing_new_read_requests5(
 				sh, s, i, disks) == 0)
@@ -2236,10 +2208,9 @@ static void handle_issuing_new_write_req
 	 * simultaneously.  If this is not the case then new writes need to be
 	 * held off until the compute completes.
 	 */
-	if ((s->req_compute ||
-	    !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending)) &&
-		(s->locked == 0 && (rcw == 0 || rmw == 0) &&
-		!test_bit(STRIPE_BIT_DELAY, &sh->state)))
+	if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
+	    (s->locked == 0 && (rcw == 0 || rmw == 0) &&
+	    !test_bit(STRIPE_BIT_DELAY, &sh->state)))
 		s->locked += handle_write_operations5(sh, rcw == 0, 0);
 }
 
@@ -2410,6 +2381,7 @@ static void handle_parity_checks5(raid5_
 				set_bit(STRIPE_INSYNC, &sh->state);
 			else {
 				sh->check_state = check_state_compute_run;
+				set_bit(STRIPE_COMPUTE_RUN, &sh->state);
 				set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
 				set_bit(R5_Wantcompute,
 					&sh->dev[sh->pd_idx].flags);
@@ -2725,8 +2697,7 @@ static void handle_stripe5(struct stripe
 	 * or to load a block that is being partially written.
 	 */
 	if (s.to_read || s.non_overwrite ||
-	    (s.syncing && (s.uptodate + s.compute < disks)) || s.expanding ||
-	    test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending))
+	    (s.syncing && (s.uptodate + s.compute < disks)) || s.expanding)
 		handle_issuing_new_read_requests5(sh, &s, disks);
 
 	/* Now we check to see if any write operations have recently
@@ -2803,7 +2774,7 @@ static void handle_stripe5(struct stripe
 	 */
 	if (sh->check_state ||
 	    (s.syncing && s.locked == 0 &&
-	     !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending) &&
+	     !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
 	     !test_bit(STRIPE_INSYNC, &sh->state)))
 		handle_parity_checks5(conf, sh, &s, disks);
 
@@ -2869,7 +2840,7 @@ static void handle_stripe5(struct stripe
 	}
 
 	if (s.expanding && s.locked == 0 &&
-	    !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending))
+	    !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
 		handle_stripe_expansion(conf, sh, NULL);
 
 	if (sh->ops.count)
@@ -3089,7 +3060,7 @@ static void handle_stripe6(struct stripe
 	}
 
 	if (s.expanding && s.locked == 0 &&
-	    !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending))
+	    !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
 		handle_stripe_expansion(conf, sh, &r6s);
 
  unlock:

[PATCH 026 of 29] md: md: replace STRIPE_OP_{BIODRAIN,PREXOR,POSTXOR} with 'reconstruct_states'

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

Track the state of reconstruct operations (recalculating the parity block
usually due to incoming writes, or as part of array expansion)  Reduces the
scope of the STRIPE_OP_{BIODRAIN,PREXOR,POSTXOR} flags to only tracking whether
a reconstruct operation has been requested via the ops_request field of struct
stripe_head_state.

This is the final step in the removal of ops.{pending,ack,complete,count}, i.e.
the STRIPE_OP_{BIODRAIN,PREXOR,POSTXOR} flags only request an operation and do
not track the state of the operation.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c         |  204 +++++++++++++------------------------------
 ./include/linux/raid/raid5.h |    9 -
 2 files changed, 63 insertions(+), 150 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:42:34.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:42:36.000000000 +1000
@@ -122,6 +122,13 @@ static void return_io(struct bio *return
 
 static void print_raid5_conf (raid5_conf_t *conf);
 
+static int stripe_operations_active(struct stripe_head *sh)
+{
+	return sh->check_state || sh->reconstruct_state ||
+	       test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
+	       test_bit(STRIPE_COMPUTE_RUN, &sh->state);
+}
+
 static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh)
 {
 	if (atomic_dec_and_test(&sh->count)) {
@@ -141,7 +148,7 @@ static void __release_stripe(raid5_conf_
 			}
 			md_wakeup_thread(conf->mddev->thread);
 		} else {
-			BUG_ON(sh->ops.pending);
+			BUG_ON(stripe_operations_active(sh));
 			if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
 				atomic_dec(&conf->preread_active_stripes);
 				if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
@@ -243,7 +250,7 @@ static void init_stripe(struct stripe_he
 
 	BUG_ON(atomic_read(&sh->count) != 0);
 	BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
-	BUG_ON(sh->ops.pending || sh->ops.ack || sh->ops.complete);
+	BUG_ON(stripe_operations_active(sh));
 
 	CHECK_DEVLOCK();
 	pr_debug("init_stripe called, stripe %llu\n",
@@ -344,47 +351,6 @@ static struct stripe_head *get_active_st
 	return sh;
 }
 
-/* test_and_ack_op() ensures that we only dequeue an operation once */
-#define test_and_ack_op(op, pend) \
-do {							\
-	if (test_bit(op, &sh->ops.pending) &&		\
-		!test_bit(op, &sh->ops.complete)) {	\
-		if (test_and_set_bit(op, &sh->ops.ack)) \
-			clear_bit(op, &pend);		\
-		else					\
-			ack++;				\
-	} else						\
-		clear_bit(op, &pend);			\
-} while (0)
-
-/* find new work to run, do not resubmit work that is already
- * in flight
- */
-static unsigned long get_stripe_work(struct stripe_head *sh)
-{
-	unsigned long pending;
-	int ack = 0;
-
-	pending = sh->ops.pending;
-
-	test_and_ack_op(STRIPE_OP_BIOFILL, pending);
-	test_and_ack_op(STRIPE_OP_COMPUTE_BLK, pending);
-	test_and_ack_op(STRIPE_OP_PREXOR, pending);
-	test_and_ack_op(STRIPE_OP_BIODRAIN, pending);
-	test_and_ack_op(STRIPE_OP_POSTXOR, pending);
-	test_and_ack_op(STRIPE_OP_CHECK, pending);
-
-	sh->ops.count -= ack;
-	if (unlikely(sh->ops.count < 0)) {
-		printk(KERN_ERR "pending: %#lx ops.pending: %#lx ops.ack: %#lx "
-			"ops.complete: %#lx\n", pending, sh->ops.pending,
-			sh->ops.ack, sh->ops.complete);
-		BUG();
-	}
-
-	return pending;
-}
-
 static void
 raid5_end_read_request(struct bio *bi, int error);
 static void
@@ -609,7 +575,7 @@ static void ops_complete_compute5(void *
 }
 
 static struct dma_async_tx_descriptor *
-ops_run_compute5(struct stripe_head *sh, unsigned long pending)
+ops_run_compute5(struct stripe_head *sh, unsigned long ops_request)
 {
 	/* kernel stack size limits the total number of disks */
 	int disks = sh->disks;
@@ -640,7 +606,7 @@ ops_run_compute5(struct stripe_head *sh,
 			ops_complete_compute5, sh);
 
 	/* ack now if postxor is not set to be run */
-	if (tx && !test_bit(STRIPE_OP_POSTXOR, &pending))
+	if (tx && !test_bit(STRIPE_OP_POSTXOR, &ops_request))
 		async_tx_ack(tx);
 
 	return tx;
@@ -652,8 +618,6 @@ static void ops_complete_prexor(void *st
 
 	pr_debug("%s: stripe %llu\n", __func__,
 		(unsigned long long)sh->sector);
-
-	set_bit(STRIPE_OP_PREXOR, &sh->ops.complete);
 }
 
 static struct dma_async_tx_descriptor *
@@ -686,7 +650,7 @@ ops_run_prexor(struct stripe_head *sh, s
 
 static struct dma_async_tx_descriptor *
 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx,
-		 unsigned long pending)
+		 unsigned long ops_request)
 {
 	int disks = sh->disks;
 	int pd_idx = sh->pd_idx, i;
@@ -694,7 +658,7 @@ ops_run_biodrain(struct stripe_head *sh,
 	/* check if prexor is active which means only process blocks
 	 * that are part of a read-modify-write (Wantprexor)
 	 */
-	int prexor = test_bit(STRIPE_OP_PREXOR, &pending);
+	int prexor = test_bit(STRIPE_OP_PREXOR, &ops_request);
 
 	pr_debug("%s: stripe %llu\n", __func__,
 		(unsigned long long)sh->sector);
@@ -744,7 +708,7 @@ static void ops_complete_postxor(void *s
 	pr_debug("%s: stripe %llu\n", __func__,
 		(unsigned long long)sh->sector);
 
-	set_bit(STRIPE_OP_POSTXOR, &sh->ops.complete);
+	sh->reconstruct_state = reconstruct_state_result;
 	set_bit(STRIPE_HANDLE, &sh->state);
 	release_stripe(sh);
 }
@@ -763,16 +727,14 @@ static void ops_complete_write(void *str
 			set_bit(R5_UPTODATE, &dev->flags);
 	}
 
-	set_bit(STRIPE_OP_BIODRAIN, &sh->ops.complete);
-	set_bit(STRIPE_OP_POSTXOR, &sh->ops.complete);
-
+	sh->reconstruct_state = reconstruct_state_drain_result;
 	set_bit(STRIPE_HANDLE, &sh->state);
 	release_stripe(sh);
 }
 
 static void
 ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx,
-		unsigned long pending)
+		unsigned long ops_request)
 {
 	/* kernel stack size limits the total number of disks */
 	int disks = sh->disks;
@@ -780,7 +742,7 @@ ops_run_postxor(struct stripe_head *sh, 
 
 	int count = 0, pd_idx = sh->pd_idx, i;
 	struct page *xor_dest;
-	int prexor = test_bit(STRIPE_OP_PREXOR, &pending);
+	int prexor = test_bit(STRIPE_OP_PREXOR, &ops_request);
 	unsigned long flags;
 	dma_async_tx_callback callback;
 
@@ -807,7 +769,7 @@ ops_run_postxor(struct stripe_head *sh, 
 	}
 
 	/* check whether this postxor is part of a write */
-	callback = test_bit(STRIPE_OP_BIODRAIN, &pending) ?
+	callback = test_bit(STRIPE_OP_BIODRAIN, &ops_request) ?
 		ops_complete_write : ops_complete_postxor;
 
 	/* 1/ if we prexor'd then the dest is reused as a source
@@ -868,8 +830,7 @@ static void ops_run_check(struct stripe_
 		ops_complete_check, sh);
 }
 
-static void raid5_run_ops(struct stripe_head *sh, unsigned long pending,
-			  unsigned long ops_request)
+static void raid5_run_ops(struct stripe_head *sh, unsigned long ops_request)
 {
 	int overlap_clear = 0, i, disks = sh->disks;
 	struct dma_async_tx_descriptor *tx = NULL;
@@ -880,18 +841,18 @@ static void raid5_run_ops(struct stripe_
 	}
 
 	if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request))
-		tx = ops_run_compute5(sh, pending);
+		tx = ops_run_compute5(sh, ops_request);
 
-	if (test_bit(STRIPE_OP_PREXOR, &pending))
+	if (test_bit(STRIPE_OP_PREXOR, &ops_request))
 		tx = ops_run_prexor(sh, tx);
 
-	if (test_bit(STRIPE_OP_BIODRAIN, &pending)) {
-		tx = ops_run_biodrain(sh, tx, pending);
+	if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
+		tx = ops_run_biodrain(sh, tx, ops_request);
 		overlap_clear++;
 	}
 
-	if (test_bit(STRIPE_OP_POSTXOR, &pending))
-		ops_run_postxor(sh, tx, pending);
+	if (test_bit(STRIPE_OP_POSTXOR, &ops_request))
+		ops_run_postxor(sh, tx, ops_request);
 
 	if (test_bit(STRIPE_OP_CHECK, &ops_request))
 		ops_run_check(sh);
@@ -1684,11 +1645,11 @@ static void compute_block_2(struct strip
 	}
 }
 
-static int
-handle_write_operations5(struct stripe_head *sh, int rcw, int expand)
+static void
+handle_write_operations5(struct stripe_head *sh, struct stripe_head_state *s,
+			 int rcw, int expand)
 {
 	int i, pd_idx = sh->pd_idx, disks = sh->disks;
-	int locked = 0;
 
 	if (rcw) {
 		/* if we are not expanding this is a proper write request, and
@@ -1696,12 +1657,12 @@ handle_write_operations5(struct stripe_h
 		 * stripe cache
 		 */
 		if (!expand) {
-			set_bit(STRIPE_OP_BIODRAIN, &sh->ops.pending);
-			sh->ops.count++;
-		}
+			sh->reconstruct_state = reconstruct_state_drain_run;
+			set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
+		} else
+			sh->reconstruct_state = reconstruct_state_run;
 
-		set_bit(STRIPE_OP_POSTXOR, &sh->ops.pending);
-		sh->ops.count++;
+		set_bit(STRIPE_OP_POSTXOR, &s->ops_request);
 
 		for (i = disks; i--; ) {
 			struct r5dev *dev = &sh->dev[i];
@@ -1710,21 +1671,20 @@ handle_write_operations5(struct stripe_h
 				set_bit(R5_LOCKED, &dev->flags);
 				if (!expand)
 					clear_bit(R5_UPTODATE, &dev->flags);
-				locked++;
+				s->locked++;
 			}
 		}
-		if (locked + 1 == disks)
+		if (s->locked + 1 == disks)
 			if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
 				atomic_inc(&sh->raid_conf->pending_full_writes);
 	} else {
 		BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
 			test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
 
-		set_bit(STRIPE_OP_PREXOR, &sh->ops.pending);
-		set_bit(STRIPE_OP_BIODRAIN, &sh->ops.pending);
-		set_bit(STRIPE_OP_POSTXOR, &sh->ops.pending);
-
-		sh->ops.count += 3;
+		sh->reconstruct_state = reconstruct_state_drain_run;
+		set_bit(STRIPE_OP_PREXOR, &s->ops_request);
+		set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
+		set_bit(STRIPE_OP_POSTXOR, &s->ops_request);
 
 		for (i = disks; i--; ) {
 			struct r5dev *dev = &sh->dev[i];
@@ -1742,7 +1702,7 @@ handle_write_operations5(struct stripe_h
 				set_bit(R5_Wantprexor, &dev->flags);
 				set_bit(R5_LOCKED, &dev->flags);
 				clear_bit(R5_UPTODATE, &dev->flags);
-				locked++;
+				s->locked++;
 			}
 		}
 	}
@@ -1752,13 +1712,11 @@ handle_write_operations5(struct stripe_h
 	 */
 	set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
 	clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
-	locked++;
+	s->locked++;
 
-	pr_debug("%s: stripe %llu locked: %d pending: %lx\n",
+	pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
 		__func__, (unsigned long long)sh->sector,
-		locked, sh->ops.pending);
-
-	return locked;
+		s->locked, s->ops_request);
 }
 
 /*
@@ -2005,8 +1963,7 @@ static void handle_issuing_new_read_requ
 	 * midst of changing due to a write
 	 */
 	if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
-	    !test_bit(STRIPE_OP_PREXOR, &sh->ops.pending) &&
-	    !test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
+	    !sh->reconstruct_state) {
 		for (i = disks; i--; )
 			if (__handle_issuing_new_read_requests5(
 				sh, s, i, disks) == 0)
@@ -2211,7 +2168,7 @@ static void handle_issuing_new_write_req
 	if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
 	    (s->locked == 0 && (rcw == 0 || rmw == 0) &&
 	    !test_bit(STRIPE_BIT_DELAY, &sh->state)))
-		s->locked += handle_write_operations5(sh, rcw == 0, 0);
+		handle_write_operations5(sh, s, rcw == 0, 0);
 }
 
 static void handle_issuing_new_write_requests6(raid5_conf_t *conf,
@@ -2581,15 +2538,14 @@ static void handle_stripe5(struct stripe
 	struct bio *return_bi = NULL;
 	struct stripe_head_state s;
 	struct r5dev *dev;
-	unsigned long pending = 0;
 	mdk_rdev_t *blocked_rdev = NULL;
 	int prexor;
 
 	memset(&s, 0, sizeof(s));
-	pr_debug("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d "
-		"ops=%lx:%lx:%lx\n", (unsigned long long)sh->sector, sh->state,
-		atomic_read(&sh->count), sh->pd_idx,
-		sh->ops.pending, sh->ops.ack, sh->ops.complete);
+	pr_debug("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d check:%d "
+		 "reconstruct:%d\n", (unsigned long long)sh->sector, sh->state,
+		 atomic_read(&sh->count), sh->pd_idx, sh->check_state,
+		 sh->reconstruct_state);
 
 	spin_lock(&sh->lock);
 	clear_bit(STRIPE_HANDLE, &sh->state);
@@ -2703,34 +2659,12 @@ static void handle_stripe5(struct stripe
 	/* Now we check to see if any write operations have recently
 	 * completed
 	 */
-
-	/* leave prexor set until postxor is done, allows us to distinguish
-	 * a rmw from a rcw during biodrain
-	 */
 	prexor = 0;
-	if (test_bit(STRIPE_OP_PREXOR, &sh->ops.complete) &&
-		test_bit(STRIPE_OP_POSTXOR, &sh->ops.complete)) {
-
-		prexor = 1;
-		clear_bit(STRIPE_OP_PREXOR, &sh->ops.complete);
-		clear_bit(STRIPE_OP_PREXOR, &sh->ops.ack);
-		clear_bit(STRIPE_OP_PREXOR, &sh->ops.pending);
-
+	if (sh->reconstruct_state == reconstruct_state_drain_result) {
+		sh->reconstruct_state = reconstruct_state_idle;
 		for (i = disks; i--; )
-			clear_bit(R5_Wantprexor, &sh->dev[i].flags);
-	}
-
-	/* if only POSTXOR is set then this is an 'expand' postxor */
-	if (test_bit(STRIPE_OP_BIODRAIN, &sh->ops.complete) &&
-		test_bit(STRIPE_OP_POSTXOR, &sh->ops.complete)) {
-
-		clear_bit(STRIPE_OP_BIODRAIN, &sh->ops.complete);
-		clear_bit(STRIPE_OP_BIODRAIN, &sh->ops.ack);
-		clear_bit(STRIPE_OP_BIODRAIN, &sh->ops.pending);
-
-		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.complete);
-		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.ack);
-		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.pending);
+			prexor += test_and_clear_bit(R5_Wantprexor,
+						     &sh->dev[i].flags);
 
 		/* All the 'written' buffers and the parity block are ready to
 		 * be written back to disk
@@ -2763,8 +2697,7 @@ static void handle_stripe5(struct stripe
 	 * 2/ A 'check' operation is in flight, as it may clobber the parity
 	 *    block.
 	 */
-	if (s.to_write && !test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending) &&
-	    !sh->check_state)
+	if (s.to_write && !sh->reconstruct_state && !sh->check_state)
 		handle_issuing_new_write_requests5(conf, sh, &s, disks);
 
 	/* maybe we need to check and possibly fix the parity for this stripe
@@ -2805,18 +2738,10 @@ static void handle_stripe5(struct stripe
 		}
 	}
 
-	/* Finish postxor operations initiated by the expansion
-	 * process
-	 */
-	if (test_bit(STRIPE_OP_POSTXOR, &sh->ops.complete) &&
-		!test_bit(STRIPE_OP_BIODRAIN, &sh->ops.pending)) {
-
+	/* Finish reconstruct operations initiated by the expansion process */
+	if (sh->reconstruct_state == reconstruct_state_result) {
+		sh->reconstruct_state = reconstruct_state_idle;
 		clear_bit(STRIPE_EXPANDING, &sh->state);
-
-		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.pending);
-		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.ack);
-		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.complete);
-
 		for (i = conf->raid_disks; i--; )
 			set_bit(R5_Wantwrite, &sh->dev[i].flags);
 			set_bit(R5_LOCKED, &dev->flags);
@@ -2824,15 +2749,13 @@ static void handle_stripe5(struct stripe
 	}
 
 	if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
-		!test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
+	    !sh->reconstruct_state) {
 		/* Need to write out all blocks after computing parity */
 		sh->disks = conf->raid_disks;
 		sh->pd_idx = stripe_to_pdidx(sh->sector, conf,
 			conf->raid_disks);
-		s.locked += handle_write_operations5(sh, 1, 1);
-	} else if (s.expanded &&
-		   s.locked == 0 &&
-		!test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
+		handle_write_operations5(sh, &s, 1, 1);
+	} else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
 		clear_bit(STRIPE_EXPAND_READY, &sh->state);
 		atomic_dec(&conf->reshape_stripes);
 		wake_up(&conf->wait_for_overlap);
@@ -2843,9 +2766,6 @@ static void handle_stripe5(struct stripe
 	    !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
 		handle_stripe_expansion(conf, sh, NULL);
 
-	if (sh->ops.count)
-		pending = get_stripe_work(sh);
-
  unlock:
 	spin_unlock(&sh->lock);
 
@@ -2853,8 +2773,8 @@ static void handle_stripe5(struct stripe
 	if (unlikely(blocked_rdev))
 		md_wait_for_blocked_rdev(blocked_rdev, conf->mddev);
 
-	if (pending || s.ops_request)
-		raid5_run_ops(sh, pending, s.ops_request);
+	if (s.ops_request)
+		raid5_run_ops(sh, s.ops_request);
 
 	ops_run_io(sh, &s);
 

diff .prev/include/linux/raid/raid5.h ./include/linux/raid/raid5.h
--- .prev/include/linux/raid/raid5.h	2008-06-27 16:42:34.000000000 +1000
+++ ./include/linux/raid/raid5.h	2008-06-27 16:42:36.000000000 +1000
@@ -205,19 +205,12 @@ struct stripe_head {
 	int			bm_seq;	/* sequence number for bitmap flushes */
 	int			disks;			/* disks in stripe */
 	enum check_states	check_state;
+	enum reconstruct_states reconstruct_state;
 	/* stripe_operations
-	 * @pending - pending ops flags (set for request->issue->complete)
-	 * @ack - submitted ops flags (set for issue->complete)
-	 * @complete - completed ops flags (set for complete)
 	 * @target - STRIPE_OP_COMPUTE_BLK target
-	 * @count - raid5_runs_ops is set to run when this is non-zero
 	 */
 	struct stripe_operations {
-		unsigned long	   pending;
-		unsigned long	   ack;
-		unsigned long	   complete;
 		int		   target;
-		int		   count;
 		u32		   zero_sum_result;
 	} ops;
 	struct r5dev {

[PATCH 026 of 29] md: md: replace STRIPE_OP_{BIODRAIN,PREXOR,POSTXOR} with 'reconstruct_states'

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

Track the state of reconstruct operations (recalculating the parity block
usually due to incoming writes, or as part of array expansion)  Reduces the
scope of the STRIPE_OP_{BIODRAIN,PREXOR,POSTXOR} flags to only tracking whether
a reconstruct operation has been requested via the ops_request field of struct
stripe_head_state.

This is the final step in the removal of ops.{pending,ack,complete,count}, i.e.
the STRIPE_OP_{BIODRAIN,PREXOR,POSTXOR} flags only request an operation and do
not track the state of the operation.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c         |  204 +++++++++++++------------------------------
 ./include/linux/raid/raid5.h |    9 -
 2 files changed, 63 insertions(+), 150 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:42:34.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:42:36.000000000 +1000
@@ -122,6 +122,13 @@ static void return_io(struct bio *return
 
 static void print_raid5_conf (raid5_conf_t *conf);
 
+static int stripe_operations_active(struct stripe_head *sh)
+{
+	return sh->check_state || sh->reconstruct_state ||
+	       test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
+	       test_bit(STRIPE_COMPUTE_RUN, &sh->state);
+}
+
 static void __release_stripe(raid5_conf_t *conf, struct stripe_head *sh)
 {
 	if (atomic_dec_and_test(&sh->count)) {
@@ -141,7 +148,7 @@ static void __release_stripe(raid5_conf_
 			}
 			md_wakeup_thread(conf->mddev->thread);
 		} else {
-			BUG_ON(sh->ops.pending);
+			BUG_ON(stripe_operations_active(sh));
 			if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
 				atomic_dec(&conf->preread_active_stripes);
 				if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
@@ -243,7 +250,7 @@ static void init_stripe(struct stripe_he
 
 	BUG_ON(atomic_read(&sh->count) != 0);
 	BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
-	BUG_ON(sh->ops.pending || sh->ops.ack || sh->ops.complete);
+	BUG_ON(stripe_operations_active(sh));
 
 	CHECK_DEVLOCK();
 	pr_debug("init_stripe called, stripe %llu\n",
@@ -344,47 +351,6 @@ static struct stripe_head *get_active_st
 	return sh;
 }
 
-/* test_and_ack_op() ensures that we only dequeue an operation once */
-#define test_and_ack_op(op, pend) \
-do {							\
-	if (test_bit(op, &sh->ops.pending) &&		\
-		!test_bit(op, &sh->ops.complete)) {	\
-		if (test_and_set_bit(op, &sh->ops.ack)) \
-			clear_bit(op, &pend);		\
-		else					\
-			ack++;				\
-	} else						\
-		clear_bit(op, &pend);			\
-} while (0)
-
-/* find new work to run, do not resubmit work that is already
- * in flight
- */
-static unsigned long get_stripe_work(struct stripe_head *sh)
-{
-	unsigned long pending;
-	int ack = 0;
-
-	pending = sh->ops.pending;
-
-	test_and_ack_op(STRIPE_OP_BIOFILL, pending);
-	test_and_ack_op(STRIPE_OP_COMPUTE_BLK, pending);
-	test_and_ack_op(STRIPE_OP_PREXOR, pending);
-	test_and_ack_op(STRIPE_OP_BIODRAIN, pending);
-	test_and_ack_op(STRIPE_OP_POSTXOR, pending);
-	test_and_ack_op(STRIPE_OP_CHECK, pending);
-
-	sh->ops.count -= ack;
-	if (unlikely(sh->ops.count < 0)) {
-		printk(KERN_ERR "pending: %#lx ops.pending: %#lx ops.ack: %#lx "
-			"ops.complete: %#lx\n", pending, sh->ops.pending,
-			sh->ops.ack, sh->ops.complete);
-		BUG();
-	}
-
-	return pending;
-}
-
 static void
 raid5_end_read_request(struct bio *bi, int error);
 static void
@@ -609,7 +575,7 @@ static void ops_complete_compute5(void *
 }
 
 static struct dma_async_tx_descriptor *
-ops_run_compute5(struct stripe_head *sh, unsigned long pending)
+ops_run_compute5(struct stripe_head *sh, unsigned long ops_request)
 {
 	/* kernel stack size limits the total number of disks */
 	int disks = sh->disks;
@@ -640,7 +606,7 @@ ops_run_compute5(struct stripe_head *sh,
 			ops_complete_compute5, sh);
 
 	/* ack now if postxor is not set to be run */
-	if (tx && !test_bit(STRIPE_OP_POSTXOR, &pending))
+	if (tx && !test_bit(STRIPE_OP_POSTXOR, &ops_request))
 		async_tx_ack(tx);
 
 	return tx;
@@ -652,8 +618,6 @@ static void ops_complete_prexor(void *st
 
 	pr_debug("%s: stripe %llu\n", __func__,
 		(unsigned long long)sh->sector);
-
-	set_bit(STRIPE_OP_PREXOR, &sh->ops.complete);
 }
 
 static struct dma_async_tx_descriptor *
@@ -686,7 +650,7 @@ ops_run_prexor(struct stripe_head *sh, s
 
 static struct dma_async_tx_descriptor *
 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx,
-		 unsigned long pending)
+		 unsigned long ops_request)
 {
 	int disks = sh->disks;
 	int pd_idx = sh->pd_idx, i;
@@ -694,7 +658,7 @@ ops_run_biodrain(struct stripe_head *sh,
 	/* check if prexor is active which means only process blocks
 	 * that are part of a read-modify-write (Wantprexor)
 	 */
-	int prexor = test_bit(STRIPE_OP_PREXOR, &pending);
+	int prexor = test_bit(STRIPE_OP_PREXOR, &ops_request);
 
 	pr_debug("%s: stripe %llu\n", __func__,
 		(unsigned long long)sh->sector);
@@ -744,7 +708,7 @@ static void ops_complete_postxor(void *s
 	pr_debug("%s: stripe %llu\n", __func__,
 		(unsigned long long)sh->sector);
 
-	set_bit(STRIPE_OP_POSTXOR, &sh->ops.complete);
+	sh->reconstruct_state = reconstruct_state_result;
 	set_bit(STRIPE_HANDLE, &sh->state);
 	release_stripe(sh);
 }
@@ -763,16 +727,14 @@ static void ops_complete_write(void *str
 			set_bit(R5_UPTODATE, &dev->flags);
 	}
 
-	set_bit(STRIPE_OP_BIODRAIN, &sh->ops.complete);
-	set_bit(STRIPE_OP_POSTXOR, &sh->ops.complete);
-
+	sh->reconstruct_state = reconstruct_state_drain_result;
 	set_bit(STRIPE_HANDLE, &sh->state);
 	release_stripe(sh);
 }
 
 static void
 ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx,
-		unsigned long pending)
+		unsigned long ops_request)
 {
 	/* kernel stack size limits the total number of disks */
 	int disks = sh->disks;
@@ -780,7 +742,7 @@ ops_run_postxor(struct stripe_head *sh, 
 
 	int count = 0, pd_idx = sh->pd_idx, i;
 	struct page *xor_dest;
-	int prexor = test_bit(STRIPE_OP_PREXOR, &pending);
+	int prexor = test_bit(STRIPE_OP_PREXOR, &ops_request);
 	unsigned long flags;
 	dma_async_tx_callback callback;
 
@@ -807,7 +769,7 @@ ops_run_postxor(struct stripe_head *sh, 
 	}
 
 	/* check whether this postxor is part of a write */
-	callback = test_bit(STRIPE_OP_BIODRAIN, &pending) ?
+	callback = test_bit(STRIPE_OP_BIODRAIN, &ops_request) ?
 		ops_complete_write : ops_complete_postxor;
 
 	/* 1/ if we prexor'd then the dest is reused as a source
@@ -868,8 +830,7 @@ static void ops_run_check(struct stripe_
 		ops_complete_check, sh);
 }
 
-static void raid5_run_ops(struct stripe_head *sh, unsigned long pending,
-			  unsigned long ops_request)
+static void raid5_run_ops(struct stripe_head *sh, unsigned long ops_request)
 {
 	int overlap_clear = 0, i, disks = sh->disks;
 	struct dma_async_tx_descriptor *tx = NULL;
@@ -880,18 +841,18 @@ static void raid5_run_ops(struct stripe_
 	}
 
 	if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request))
-		tx = ops_run_compute5(sh, pending);
+		tx = ops_run_compute5(sh, ops_request);
 
-	if (test_bit(STRIPE_OP_PREXOR, &pending))
+	if (test_bit(STRIPE_OP_PREXOR, &ops_request))
 		tx = ops_run_prexor(sh, tx);
 
-	if (test_bit(STRIPE_OP_BIODRAIN, &pending)) {
-		tx = ops_run_biodrain(sh, tx, pending);
+	if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
+		tx = ops_run_biodrain(sh, tx, ops_request);
 		overlap_clear++;
 	}
 
-	if (test_bit(STRIPE_OP_POSTXOR, &pending))
-		ops_run_postxor(sh, tx, pending);
+	if (test_bit(STRIPE_OP_POSTXOR, &ops_request))
+		ops_run_postxor(sh, tx, ops_request);
 
 	if (test_bit(STRIPE_OP_CHECK, &ops_request))
 		ops_run_check(sh);
@@ -1684,11 +1645,11 @@ static void compute_block_2(struct strip
 	}
 }
 
-static int
-handle_write_operations5(struct stripe_head *sh, int rcw, int expand)
+static void
+handle_write_operations5(struct stripe_head *sh, struct stripe_head_state *s,
+			 int rcw, int expand)
 {
 	int i, pd_idx = sh->pd_idx, disks = sh->disks;
-	int locked = 0;
 
 	if (rcw) {
 		/* if we are not expanding this is a proper write request, and
@@ -1696,12 +1657,12 @@ handle_write_operations5(struct stripe_h
 		 * stripe cache
 		 */
 		if (!expand) {
-			set_bit(STRIPE_OP_BIODRAIN, &sh->ops.pending);
-			sh->ops.count++;
-		}
+			sh->reconstruct_state = reconstruct_state_drain_run;
+			set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
+		} else
+			sh->reconstruct_state = reconstruct_state_run;
 
-		set_bit(STRIPE_OP_POSTXOR, &sh->ops.pending);
-		sh->ops.count++;
+		set_bit(STRIPE_OP_POSTXOR, &s->ops_request);
 
 		for (i = disks; i--; ) {
 			struct r5dev *dev = &sh->dev[i];
@@ -1710,21 +1671,20 @@ handle_write_operations5(struct stripe_h
 				set_bit(R5_LOCKED, &dev->flags);
 				if (!expand)
 					clear_bit(R5_UPTODATE, &dev->flags);
-				locked++;
+				s->locked++;
 			}
 		}
-		if (locked + 1 == disks)
+		if (s->locked + 1 == disks)
 			if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
 				atomic_inc(&sh->raid_conf->pending_full_writes);
 	} else {
 		BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
 			test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
 
-		set_bit(STRIPE_OP_PREXOR, &sh->ops.pending);
-		set_bit(STRIPE_OP_BIODRAIN, &sh->ops.pending);
-		set_bit(STRIPE_OP_POSTXOR, &sh->ops.pending);
-
-		sh->ops.count += 3;
+		sh->reconstruct_state = reconstruct_state_drain_run;
+		set_bit(STRIPE_OP_PREXOR, &s->ops_request);
+		set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
+		set_bit(STRIPE_OP_POSTXOR, &s->ops_request);
 
 		for (i = disks; i--; ) {
 			struct r5dev *dev = &sh->dev[i];
@@ -1742,7 +1702,7 @@ handle_write_operations5(struct stripe_h
 				set_bit(R5_Wantprexor, &dev->flags);
 				set_bit(R5_LOCKED, &dev->flags);
 				clear_bit(R5_UPTODATE, &dev->flags);
-				locked++;
+				s->locked++;
 			}
 		}
 	}
@@ -1752,13 +1712,11 @@ handle_write_operations5(struct stripe_h
 	 */
 	set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
 	clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
-	locked++;
+	s->locked++;
 
-	pr_debug("%s: stripe %llu locked: %d pending: %lx\n",
+	pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
 		__func__, (unsigned long long)sh->sector,
-		locked, sh->ops.pending);
-
-	return locked;
+		s->locked, s->ops_request);
 }
 
 /*
@@ -2005,8 +1963,7 @@ static void handle_issuing_new_read_requ
 	 * midst of changing due to a write
 	 */
 	if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
-	    !test_bit(STRIPE_OP_PREXOR, &sh->ops.pending) &&
-	    !test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
+	    !sh->reconstruct_state) {
 		for (i = disks; i--; )
 			if (__handle_issuing_new_read_requests5(
 				sh, s, i, disks) == 0)
@@ -2211,7 +2168,7 @@ static void handle_issuing_new_write_req
 	if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
 	    (s->locked == 0 && (rcw == 0 || rmw == 0) &&
 	    !test_bit(STRIPE_BIT_DELAY, &sh->state)))
-		s->locked += handle_write_operations5(sh, rcw == 0, 0);
+		handle_write_operations5(sh, s, rcw == 0, 0);
 }
 
 static void handle_issuing_new_write_requests6(raid5_conf_t *conf,
@@ -2581,15 +2538,14 @@ static void handle_stripe5(struct stripe
 	struct bio *return_bi = NULL;
 	struct stripe_head_state s;
 	struct r5dev *dev;
-	unsigned long pending = 0;
 	mdk_rdev_t *blocked_rdev = NULL;
 	int prexor;
 
 	memset(&s, 0, sizeof(s));
-	pr_debug("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d "
-		"ops=%lx:%lx:%lx\n", (unsigned long long)sh->sector, sh->state,
-		atomic_read(&sh->count), sh->pd_idx,
-		sh->ops.pending, sh->ops.ack, sh->ops.complete);
+	pr_debug("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d check:%d "
+		 "reconstruct:%d\n", (unsigned long long)sh->sector, sh->state,
+		 atomic_read(&sh->count), sh->pd_idx, sh->check_state,
+		 sh->reconstruct_state);
 
 	spin_lock(&sh->lock);
 	clear_bit(STRIPE_HANDLE, &sh->state);
@@ -2703,34 +2659,12 @@ static void handle_stripe5(struct stripe
 	/* Now we check to see if any write operations have recently
 	 * completed
 	 */
-
-	/* leave prexor set until postxor is done, allows us to distinguish
-	 * a rmw from a rcw during biodrain
-	 */
 	prexor = 0;
-	if (test_bit(STRIPE_OP_PREXOR, &sh->ops.complete) &&
-		test_bit(STRIPE_OP_POSTXOR, &sh->ops.complete)) {
-
-		prexor = 1;
-		clear_bit(STRIPE_OP_PREXOR, &sh->ops.complete);
-		clear_bit(STRIPE_OP_PREXOR, &sh->ops.ack);
-		clear_bit(STRIPE_OP_PREXOR, &sh->ops.pending);
-
+	if (sh->reconstruct_state == reconstruct_state_drain_result) {
+		sh->reconstruct_state = reconstruct_state_idle;
 		for (i = disks; i--; )
-			clear_bit(R5_Wantprexor, &sh->dev[i].flags);
-	}
-
-	/* if only POSTXOR is set then this is an 'expand' postxor */
-	if (test_bit(STRIPE_OP_BIODRAIN, &sh->ops.complete) &&
-		test_bit(STRIPE_OP_POSTXOR, &sh->ops.complete)) {
-
-		clear_bit(STRIPE_OP_BIODRAIN, &sh->ops.complete);
-		clear_bit(STRIPE_OP_BIODRAIN, &sh->ops.ack);
-		clear_bit(STRIPE_OP_BIODRAIN, &sh->ops.pending);
-
-		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.complete);
-		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.ack);
-		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.pending);
+			prexor += test_and_clear_bit(R5_Wantprexor,
+						     &sh->dev[i].flags);
 
 		/* All the 'written' buffers and the parity block are ready to
 		 * be written back to disk
@@ -2763,8 +2697,7 @@ static void handle_stripe5(struct stripe
 	 * 2/ A 'check' operation is in flight, as it may clobber the parity
 	 *    block.
 	 */
-	if (s.to_write && !test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending) &&
-	    !sh->check_state)
+	if (s.to_write && !sh->reconstruct_state && !sh->check_state)
 		handle_issuing_new_write_requests5(conf, sh, &s, disks);
 
 	/* maybe we need to check and possibly fix the parity for this stripe
@@ -2805,18 +2738,10 @@ static void handle_stripe5(struct stripe
 		}
 	}
 
-	/* Finish postxor operations initiated by the expansion
-	 * process
-	 */
-	if (test_bit(STRIPE_OP_POSTXOR, &sh->ops.complete) &&
-		!test_bit(STRIPE_OP_BIODRAIN, &sh->ops.pending)) {
-
+	/* Finish reconstruct operations initiated by the expansion process */
+	if (sh->reconstruct_state == reconstruct_state_result) {
+		sh->reconstruct_state = reconstruct_state_idle;
 		clear_bit(STRIPE_EXPANDING, &sh->state);
-
-		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.pending);
-		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.ack);
-		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.complete);
-
 		for (i = conf->raid_disks; i--; )
 			set_bit(R5_Wantwrite, &sh->dev[i].flags);
 			set_bit(R5_LOCKED, &dev->flags);
@@ -2824,15 +2749,13 @@ static void handle_stripe5(struct stripe
 	}
 
 	if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
-		!test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
+	    !sh->reconstruct_state) {
 		/* Need to write out all blocks after computing parity */
 		sh->disks = conf->raid_disks;
 		sh->pd_idx = stripe_to_pdidx(sh->sector, conf,
 			conf->raid_disks);
-		s.locked += handle_write_operations5(sh, 1, 1);
-	} else if (s.expanded &&
-		   s.locked == 0 &&
-		!test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
+		handle_write_operations5(sh, &s, 1, 1);
+	} else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
 		clear_bit(STRIPE_EXPAND_READY, &sh->state);
 		atomic_dec(&conf->reshape_stripes);
 		wake_up(&conf->wait_for_overlap);
@@ -2843,9 +2766,6 @@ static void handle_stripe5(struct stripe
 	    !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
 		handle_stripe_expansion(conf, sh, NULL);
 
-	if (sh->ops.count)
-		pending = get_stripe_work(sh);
-
  unlock:
 	spin_unlock(&sh->lock);
 
@@ -2853,8 +2773,8 @@ static void handle_stripe5(struct stripe
 	if (unlikely(blocked_rdev))
 		md_wait_for_blocked_rdev(blocked_rdev, conf->mddev);
 
-	if (pending || s.ops_request)
-		raid5_run_ops(sh, pending, s.ops_request);
+	if (s.ops_request)
+		raid5_run_ops(sh, s.ops_request);
 
 	ops_run_io(sh, &s);
 

diff .prev/include/linux/raid/raid5.h ./include/linux/raid/raid5.h
--- .prev/include/linux/raid/raid5.h	2008-06-27 16:42:34.000000000 +1000
+++ ./include/linux/raid/raid5.h	2008-06-27 16:42:36.000000000 +1000
@@ -205,19 +205,12 @@ struct stripe_head {
 	int			bm_seq;	/* sequence number for bitmap flushes */
 	int			disks;			/* disks in stripe */
 	enum check_states	check_state;
+	enum reconstruct_states reconstruct_state;
 	/* stripe_operations
-	 * @pending - pending ops flags (set for request->issue->complete)
-	 * @ack - submitted ops flags (set for issue->complete)
-	 * @complete - completed ops flags (set for complete)
 	 * @target - STRIPE_OP_COMPUTE_BLK target
-	 * @count - raid5_runs_ops is set to run when this is non-zero
 	 */
 	struct stripe_operations {
-		unsigned long	   pending;
-		unsigned long	   ack;
-		unsigned long	   complete;
 		int		   target;
-		int		   count;
 		u32		   zero_sum_result;
 	} ops;
 	struct r5dev {

[PATCH 027 of 29] md: md: replace R5_WantPrexor with R5_WantDrain, add 'prexor' reconstruct_states

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

Currently ops_run_biodrain and other locations have extra logic to determine
which blocks are processed in the prexor and non-prexor cases.  This can be
eliminated if handle_write_operations5 flags the blocks to be processed in all
cases via R5_Wantdrain.  The presence of the prexor operation is tracked in
sh->reconstruct_state.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c         |   89 ++++++++++++++-----------------------------
 ./include/linux/raid/raid5.h |    6 +-
 2 files changed, 32 insertions(+), 63 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:42:36.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:42:56.000000000 +1000
@@ -637,7 +637,7 @@ ops_run_prexor(struct stripe_head *sh, s
 	for (i = disks; i--; ) {
 		struct r5dev *dev = &sh->dev[i];
 		/* Only process blocks that are known to be uptodate */
-		if (dev->towrite && test_bit(R5_Wantprexor, &dev->flags))
+		if (test_bit(R5_Wantdrain, &dev->flags))
 			xor_srcs[count++] = dev->page;
 	}
 
@@ -649,16 +649,10 @@ ops_run_prexor(struct stripe_head *sh, s
 }
 
 static struct dma_async_tx_descriptor *
-ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx,
-		 unsigned long ops_request)
+ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
 {
 	int disks = sh->disks;
-	int pd_idx = sh->pd_idx, i;
-
-	/* check if prexor is active which means only process blocks
-	 * that are part of a read-modify-write (Wantprexor)
-	 */
-	int prexor = test_bit(STRIPE_OP_PREXOR, &ops_request);
+	int i;
 
 	pr_debug("%s: stripe %llu\n", __func__,
 		(unsigned long long)sh->sector);
@@ -666,20 +660,8 @@ ops_run_biodrain(struct stripe_head *sh,
 	for (i = disks; i--; ) {
 		struct r5dev *dev = &sh->dev[i];
 		struct bio *chosen;
-		int towrite;
 
-		towrite = 0;
-		if (prexor) { /* rmw */
-			if (dev->towrite &&
-			    test_bit(R5_Wantprexor, &dev->flags))
-				towrite = 1;
-		} else { /* rcw */
-			if (i != pd_idx && dev->towrite &&
-				test_bit(R5_LOCKED, &dev->flags))
-				towrite = 1;
-		}
-
-		if (towrite) {
+		if (test_and_clear_bit(R5_Wantdrain, &dev->flags)) {
 			struct bio *wbi;
 
 			spin_lock(&sh->lock);
@@ -704,18 +686,6 @@ ops_run_biodrain(struct stripe_head *sh,
 static void ops_complete_postxor(void *stripe_head_ref)
 {
 	struct stripe_head *sh = stripe_head_ref;
-
-	pr_debug("%s: stripe %llu\n", __func__,
-		(unsigned long long)sh->sector);
-
-	sh->reconstruct_state = reconstruct_state_result;
-	set_bit(STRIPE_HANDLE, &sh->state);
-	release_stripe(sh);
-}
-
-static void ops_complete_write(void *stripe_head_ref)
-{
-	struct stripe_head *sh = stripe_head_ref;
 	int disks = sh->disks, i, pd_idx = sh->pd_idx;
 
 	pr_debug("%s: stripe %llu\n", __func__,
@@ -727,14 +697,21 @@ static void ops_complete_write(void *str
 			set_bit(R5_UPTODATE, &dev->flags);
 	}
 
-	sh->reconstruct_state = reconstruct_state_drain_result;
+	if (sh->reconstruct_state == reconstruct_state_drain_run)
+		sh->reconstruct_state = reconstruct_state_drain_result;
+	else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
+		sh->reconstruct_state = reconstruct_state_prexor_drain_result;
+	else {
+		BUG_ON(sh->reconstruct_state != reconstruct_state_run);
+		sh->reconstruct_state = reconstruct_state_result;
+	}
+
 	set_bit(STRIPE_HANDLE, &sh->state);
 	release_stripe(sh);
 }
 
 static void
-ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx,
-		unsigned long ops_request)
+ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
 {
 	/* kernel stack size limits the total number of disks */
 	int disks = sh->disks;
@@ -742,9 +719,8 @@ ops_run_postxor(struct stripe_head *sh, 
 
 	int count = 0, pd_idx = sh->pd_idx, i;
 	struct page *xor_dest;
-	int prexor = test_bit(STRIPE_OP_PREXOR, &ops_request);
+	int prexor = 0;
 	unsigned long flags;
-	dma_async_tx_callback callback;
 
 	pr_debug("%s: stripe %llu\n", __func__,
 		(unsigned long long)sh->sector);
@@ -752,7 +728,8 @@ ops_run_postxor(struct stripe_head *sh, 
 	/* check if prexor is active which means only process blocks
 	 * that are part of a read-modify-write (written)
 	 */
-	if (prexor) {
+	if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
+		prexor = 1;
 		xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
 		for (i = disks; i--; ) {
 			struct r5dev *dev = &sh->dev[i];
@@ -768,10 +745,6 @@ ops_run_postxor(struct stripe_head *sh, 
 		}
 	}
 
-	/* check whether this postxor is part of a write */
-	callback = test_bit(STRIPE_OP_BIODRAIN, &ops_request) ?
-		ops_complete_write : ops_complete_postxor;
-
 	/* 1/ if we prexor'd then the dest is reused as a source
 	 * 2/ if we did not prexor then we are redoing the parity
 	 * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
@@ -785,10 +758,10 @@ ops_run_postxor(struct stripe_head *sh, 
 	if (unlikely(count == 1)) {
 		flags &= ~(ASYNC_TX_XOR_DROP_DST | ASYNC_TX_XOR_ZERO_DST);
 		tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE,
-			flags, tx, callback, sh);
+			flags, tx, ops_complete_postxor, sh);
 	} else
 		tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
-			flags, tx, callback, sh);
+			flags, tx, ops_complete_postxor, sh);
 }
 
 static void ops_complete_check(void *stripe_head_ref)
@@ -847,12 +820,12 @@ static void raid5_run_ops(struct stripe_
 		tx = ops_run_prexor(sh, tx);
 
 	if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
-		tx = ops_run_biodrain(sh, tx, ops_request);
+		tx = ops_run_biodrain(sh, tx);
 		overlap_clear++;
 	}
 
 	if (test_bit(STRIPE_OP_POSTXOR, &ops_request))
-		ops_run_postxor(sh, tx, ops_request);
+		ops_run_postxor(sh, tx);
 
 	if (test_bit(STRIPE_OP_CHECK, &ops_request))
 		ops_run_check(sh);
@@ -1669,6 +1642,7 @@ handle_write_operations5(struct stripe_h
 
 			if (dev->towrite) {
 				set_bit(R5_LOCKED, &dev->flags);
+				set_bit(R5_Wantdrain, &dev->flags);
 				if (!expand)
 					clear_bit(R5_UPTODATE, &dev->flags);
 				s->locked++;
@@ -1681,7 +1655,7 @@ handle_write_operations5(struct stripe_h
 		BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
 			test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
 
-		sh->reconstruct_state = reconstruct_state_drain_run;
+		sh->reconstruct_state = reconstruct_state_prexor_drain_run;
 		set_bit(STRIPE_OP_PREXOR, &s->ops_request);
 		set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
 		set_bit(STRIPE_OP_POSTXOR, &s->ops_request);
@@ -1691,15 +1665,10 @@ handle_write_operations5(struct stripe_h
 			if (i == pd_idx)
 				continue;
 
-			/* For a read-modify write there may be blocks that are
-			 * locked for reading while others are ready to be
-			 * written so we distinguish these blocks by the
-			 * R5_Wantprexor bit
-			 */
 			if (dev->towrite &&
 			    (test_bit(R5_UPTODATE, &dev->flags) ||
-			    test_bit(R5_Wantcompute, &dev->flags))) {
-				set_bit(R5_Wantprexor, &dev->flags);
+			     test_bit(R5_Wantcompute, &dev->flags))) {
+				set_bit(R5_Wantdrain, &dev->flags);
 				set_bit(R5_LOCKED, &dev->flags);
 				clear_bit(R5_UPTODATE, &dev->flags);
 				s->locked++;
@@ -2660,11 +2629,11 @@ static void handle_stripe5(struct stripe
 	 * completed
 	 */
 	prexor = 0;
-	if (sh->reconstruct_state == reconstruct_state_drain_result) {
+	if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
+		prexor = 1;
+	if (sh->reconstruct_state == reconstruct_state_drain_result ||
+	    sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
 		sh->reconstruct_state = reconstruct_state_idle;
-		for (i = disks; i--; )
-			prexor += test_and_clear_bit(R5_Wantprexor,
-						     &sh->dev[i].flags);
 
 		/* All the 'written' buffers and the parity block are ready to
 		 * be written back to disk

diff .prev/include/linux/raid/raid5.h ./include/linux/raid/raid5.h
--- .prev/include/linux/raid/raid5.h	2008-06-27 16:42:36.000000000 +1000
+++ ./include/linux/raid/raid5.h	2008-06-27 16:42:56.000000000 +1000
@@ -187,8 +187,10 @@ enum check_states {
  */
 enum reconstruct_states {
 	reconstruct_state_idle = 0,
+	reconstruct_state_prexor_drain_run,	/* prexor-write */
 	reconstruct_state_drain_run,		/* write */
 	reconstruct_state_run,			/* expand */
+	reconstruct_state_prexor_drain_result,
 	reconstruct_state_drain_result,
 	reconstruct_state_result,
 };
@@ -258,9 +260,7 @@ struct r6_state {
 #define	R5_Wantfill	12 /* dev->toread contains a bio that needs
 				    * filling
 				    */
-#define	R5_Wantprexor	13 /* distinguish blocks ready for rmw from
-				    * other "towrites"
-				    */
+#define R5_Wantdrain	13 /* dev->towrite needs to be drained */
 /*
  * Write method
  */

[PATCH 027 of 29] md: md: replace R5_WantPrexor with R5_WantDrain, add 'prexor' reconstruct_states

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

Currently ops_run_biodrain and other locations have extra logic to determine
which blocks are processed in the prexor and non-prexor cases.  This can be
eliminated if handle_write_operations5 flags the blocks to be processed in all
cases via R5_Wantdrain.  The presence of the prexor operation is tracked in
sh->reconstruct_state.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c         |   89 ++++++++++++++-----------------------------
 ./include/linux/raid/raid5.h |    6 +-
 2 files changed, 32 insertions(+), 63 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:42:36.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:42:56.000000000 +1000
@@ -637,7 +637,7 @@ ops_run_prexor(struct stripe_head *sh, s
 	for (i = disks; i--; ) {
 		struct r5dev *dev = &sh->dev[i];
 		/* Only process blocks that are known to be uptodate */
-		if (dev->towrite && test_bit(R5_Wantprexor, &dev->flags))
+		if (test_bit(R5_Wantdrain, &dev->flags))
 			xor_srcs[count++] = dev->page;
 	}
 
@@ -649,16 +649,10 @@ ops_run_prexor(struct stripe_head *sh, s
 }
 
 static struct dma_async_tx_descriptor *
-ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx,
-		 unsigned long ops_request)
+ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
 {
 	int disks = sh->disks;
-	int pd_idx = sh->pd_idx, i;
-
-	/* check if prexor is active which means only process blocks
-	 * that are part of a read-modify-write (Wantprexor)
-	 */
-	int prexor = test_bit(STRIPE_OP_PREXOR, &ops_request);
+	int i;
 
 	pr_debug("%s: stripe %llu\n", __func__,
 		(unsigned long long)sh->sector);
@@ -666,20 +660,8 @@ ops_run_biodrain(struct stripe_head *sh,
 	for (i = disks; i--; ) {
 		struct r5dev *dev = &sh->dev[i];
 		struct bio *chosen;
-		int towrite;
 
-		towrite = 0;
-		if (prexor) { /* rmw */
-			if (dev->towrite &&
-			    test_bit(R5_Wantprexor, &dev->flags))
-				towrite = 1;
-		} else { /* rcw */
-			if (i != pd_idx && dev->towrite &&
-				test_bit(R5_LOCKED, &dev->flags))
-				towrite = 1;
-		}
-
-		if (towrite) {
+		if (test_and_clear_bit(R5_Wantdrain, &dev->flags)) {
 			struct bio *wbi;
 
 			spin_lock(&sh->lock);
@@ -704,18 +686,6 @@ ops_run_biodrain(struct stripe_head *sh,
 static void ops_complete_postxor(void *stripe_head_ref)
 {
 	struct stripe_head *sh = stripe_head_ref;
-
-	pr_debug("%s: stripe %llu\n", __func__,
-		(unsigned long long)sh->sector);
-
-	sh->reconstruct_state = reconstruct_state_result;
-	set_bit(STRIPE_HANDLE, &sh->state);
-	release_stripe(sh);
-}
-
-static void ops_complete_write(void *stripe_head_ref)
-{
-	struct stripe_head *sh = stripe_head_ref;
 	int disks = sh->disks, i, pd_idx = sh->pd_idx;
 
 	pr_debug("%s: stripe %llu\n", __func__,
@@ -727,14 +697,21 @@ static void ops_complete_write(void *str
 			set_bit(R5_UPTODATE, &dev->flags);
 	}
 
-	sh->reconstruct_state = reconstruct_state_drain_result;
+	if (sh->reconstruct_state == reconstruct_state_drain_run)
+		sh->reconstruct_state = reconstruct_state_drain_result;
+	else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
+		sh->reconstruct_state = reconstruct_state_prexor_drain_result;
+	else {
+		BUG_ON(sh->reconstruct_state != reconstruct_state_run);
+		sh->reconstruct_state = reconstruct_state_result;
+	}
+
 	set_bit(STRIPE_HANDLE, &sh->state);
 	release_stripe(sh);
 }
 
 static void
-ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx,
-		unsigned long ops_request)
+ops_run_postxor(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
 {
 	/* kernel stack size limits the total number of disks */
 	int disks = sh->disks;
@@ -742,9 +719,8 @@ ops_run_postxor(struct stripe_head *sh, 
 
 	int count = 0, pd_idx = sh->pd_idx, i;
 	struct page *xor_dest;
-	int prexor = test_bit(STRIPE_OP_PREXOR, &ops_request);
+	int prexor = 0;
 	unsigned long flags;
-	dma_async_tx_callback callback;
 
 	pr_debug("%s: stripe %llu\n", __func__,
 		(unsigned long long)sh->sector);
@@ -752,7 +728,8 @@ ops_run_postxor(struct stripe_head *sh, 
 	/* check if prexor is active which means only process blocks
 	 * that are part of a read-modify-write (written)
 	 */
-	if (prexor) {
+	if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
+		prexor = 1;
 		xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
 		for (i = disks; i--; ) {
 			struct r5dev *dev = &sh->dev[i];
@@ -768,10 +745,6 @@ ops_run_postxor(struct stripe_head *sh, 
 		}
 	}
 
-	/* check whether this postxor is part of a write */
-	callback = test_bit(STRIPE_OP_BIODRAIN, &ops_request) ?
-		ops_complete_write : ops_complete_postxor;
-
 	/* 1/ if we prexor'd then the dest is reused as a source
 	 * 2/ if we did not prexor then we are redoing the parity
 	 * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
@@ -785,10 +758,10 @@ ops_run_postxor(struct stripe_head *sh, 
 	if (unlikely(count == 1)) {
 		flags &= ~(ASYNC_TX_XOR_DROP_DST | ASYNC_TX_XOR_ZERO_DST);
 		tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE,
-			flags, tx, callback, sh);
+			flags, tx, ops_complete_postxor, sh);
 	} else
 		tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
-			flags, tx, callback, sh);
+			flags, tx, ops_complete_postxor, sh);
 }
 
 static void ops_complete_check(void *stripe_head_ref)
@@ -847,12 +820,12 @@ static void raid5_run_ops(struct stripe_
 		tx = ops_run_prexor(sh, tx);
 
 	if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
-		tx = ops_run_biodrain(sh, tx, ops_request);
+		tx = ops_run_biodrain(sh, tx);
 		overlap_clear++;
 	}
 
 	if (test_bit(STRIPE_OP_POSTXOR, &ops_request))
-		ops_run_postxor(sh, tx, ops_request);
+		ops_run_postxor(sh, tx);
 
 	if (test_bit(STRIPE_OP_CHECK, &ops_request))
 		ops_run_check(sh);
@@ -1669,6 +1642,7 @@ handle_write_operations5(struct stripe_h
 
 			if (dev->towrite) {
 				set_bit(R5_LOCKED, &dev->flags);
+				set_bit(R5_Wantdrain, &dev->flags);
 				if (!expand)
 					clear_bit(R5_UPTODATE, &dev->flags);
 				s->locked++;
@@ -1681,7 +1655,7 @@ handle_write_operations5(struct stripe_h
 		BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
 			test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
 
-		sh->reconstruct_state = reconstruct_state_drain_run;
+		sh->reconstruct_state = reconstruct_state_prexor_drain_run;
 		set_bit(STRIPE_OP_PREXOR, &s->ops_request);
 		set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
 		set_bit(STRIPE_OP_POSTXOR, &s->ops_request);
@@ -1691,15 +1665,10 @@ handle_write_operations5(struct stripe_h
 			if (i == pd_idx)
 				continue;
 
-			/* For a read-modify write there may be blocks that are
-			 * locked for reading while others are ready to be
-			 * written so we distinguish these blocks by the
-			 * R5_Wantprexor bit
-			 */
 			if (dev->towrite &&
 			    (test_bit(R5_UPTODATE, &dev->flags) ||
-			    test_bit(R5_Wantcompute, &dev->flags))) {
-				set_bit(R5_Wantprexor, &dev->flags);
+			     test_bit(R5_Wantcompute, &dev->flags))) {
+				set_bit(R5_Wantdrain, &dev->flags);
 				set_bit(R5_LOCKED, &dev->flags);
 				clear_bit(R5_UPTODATE, &dev->flags);
 				s->locked++;
@@ -2660,11 +2629,11 @@ static void handle_stripe5(struct stripe
 	 * completed
 	 */
 	prexor = 0;
-	if (sh->reconstruct_state == reconstruct_state_drain_result) {
+	if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
+		prexor = 1;
+	if (sh->reconstruct_state == reconstruct_state_drain_result ||
+	    sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
 		sh->reconstruct_state = reconstruct_state_idle;
-		for (i = disks; i--; )
-			prexor += test_and_clear_bit(R5_Wantprexor,
-						     &sh->dev[i].flags);
 
 		/* All the 'written' buffers and the parity block are ready to
 		 * be written back to disk

diff .prev/include/linux/raid/raid5.h ./include/linux/raid/raid5.h
--- .prev/include/linux/raid/raid5.h	2008-06-27 16:42:36.000000000 +1000
+++ ./include/linux/raid/raid5.h	2008-06-27 16:42:56.000000000 +1000
@@ -187,8 +187,10 @@ enum check_states {
  */
 enum reconstruct_states {
 	reconstruct_state_idle = 0,
+	reconstruct_state_prexor_drain_run,	/* prexor-write */
 	reconstruct_state_drain_run,		/* write */
 	reconstruct_state_run,			/* expand */
+	reconstruct_state_prexor_drain_result,
 	reconstruct_state_drain_result,
 	reconstruct_state_result,
 };
@@ -258,9 +260,7 @@ struct r6_state {
 #define	R5_Wantfill	12 /* dev->toread contains a bio that needs
 				    * filling
 				    */
-#define	R5_Wantprexor	13 /* distinguish blocks ready for rmw from
-				    * other "towrites"
-				    */
+#define R5_Wantdrain	13 /* dev->towrite needs to be drained */
 /*
  * Write method
  */

[PATCH 028 of 29] md: md: handle operation chaining in raid5_run_ops

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

Neil said:
> At the end of ops_run_compute5 you have:
>         /* ack now if postxor is not set to be run */
>         if (tx && !test_bit(STRIPE_OP_POSTXOR, &s->ops_run))
>                 async_tx_ack(tx);
>
> It looks odd having that test there.  Would it fit in raid5_run_ops
> better?

The intended global interpretation is that raid5_run_ops can build a chain
of xor and memcpy operations.  When MD registers the compute-xor it tells
async_tx to keep the operation handle around so that another item in the
dependency chain can be submitted. If we are just computing a block to
satisfy a read then we can terminate the chain immediately.  raid5_run_ops
gives a better context for this test since it cares about the entire chain.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c |   15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:42:56.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:42:56.000000000 +1000
@@ -574,8 +574,7 @@ static void ops_complete_compute5(void *
 	release_stripe(sh);
 }
 
-static struct dma_async_tx_descriptor *
-ops_run_compute5(struct stripe_head *sh, unsigned long ops_request)
+static struct dma_async_tx_descriptor *ops_run_compute5(struct stripe_head *sh)
 {
 	/* kernel stack size limits the total number of disks */
 	int disks = sh->disks;
@@ -605,10 +604,6 @@ ops_run_compute5(struct stripe_head *sh,
 			ASYNC_TX_XOR_ZERO_DST, NULL,
 			ops_complete_compute5, sh);
 
-	/* ack now if postxor is not set to be run */
-	if (tx && !test_bit(STRIPE_OP_POSTXOR, &ops_request))
-		async_tx_ack(tx);
-
 	return tx;
 }
 
@@ -813,8 +808,12 @@ static void raid5_run_ops(struct stripe_
 		overlap_clear++;
 	}
 
-	if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request))
-		tx = ops_run_compute5(sh, ops_request);
+	if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
+		tx = ops_run_compute5(sh);
+		/* terminate the chain if postxor is not set to be run */
+		if (tx && !test_bit(STRIPE_OP_POSTXOR, &ops_request))
+			async_tx_ack(tx);
+	}
 
 	if (test_bit(STRIPE_OP_PREXOR, &ops_request))
 		tx = ops_run_prexor(sh, tx);

[PATCH 028 of 29] md: md: handle operation chaining in raid5_run_ops

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

Neil said:
> At the end of ops_run_compute5 you have:
>         /* ack now if postxor is not set to be run */
>         if (tx && !test_bit(STRIPE_OP_POSTXOR, &s->ops_run))
>                 async_tx_ack(tx);
>
> It looks odd having that test there.  Would it fit in raid5_run_ops
> better?

The intended global interpretation is that raid5_run_ops can build a chain
of xor and memcpy operations.  When MD registers the compute-xor it tells
async_tx to keep the operation handle around so that another item in the
dependency chain can be submitted. If we are just computing a block to
satisfy a read then we can terminate the chain immediately.  raid5_run_ops
gives a better context for this test since it cares about the entire chain.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c |   15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:42:56.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:42:56.000000000 +1000
@@ -574,8 +574,7 @@ static void ops_complete_compute5(void *
 	release_stripe(sh);
 }
 
-static struct dma_async_tx_descriptor *
-ops_run_compute5(struct stripe_head *sh, unsigned long ops_request)
+static struct dma_async_tx_descriptor *ops_run_compute5(struct stripe_head *sh)
 {
 	/* kernel stack size limits the total number of disks */
 	int disks = sh->disks;
@@ -605,10 +604,6 @@ ops_run_compute5(struct stripe_head *sh,
 			ASYNC_TX_XOR_ZERO_DST, NULL,
 			ops_complete_compute5, sh);
 
-	/* ack now if postxor is not set to be run */
-	if (tx && !test_bit(STRIPE_OP_POSTXOR, &ops_request))
-		async_tx_ack(tx);
-
 	return tx;
 }
 
@@ -813,8 +808,12 @@ static void raid5_run_ops(struct stripe_
 		overlap_clear++;
 	}
 
-	if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request))
-		tx = ops_run_compute5(sh, ops_request);
+	if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
+		tx = ops_run_compute5(sh);
+		/* terminate the chain if postxor is not set to be run */
+		if (tx && !test_bit(STRIPE_OP_POSTXOR, &ops_request))
+			async_tx_ack(tx);
+	}
 
 	if (test_bit(STRIPE_OP_PREXOR, &ops_request))
 		tx = ops_run_prexor(sh, tx);

[PATCH 029 of 29] md: md: rationalize raid5 function names

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

Commit a4456856 refactored some of the deep code paths in raid5.c into separate
functions.  The names chosen at the time do not consistently indicate what is
going to happen to the stripe.  So, update the names, and since a stripe is a
cache element use cache semantics like fill, dirty, and clean.

(also, fix up the indentation in fetch_block5)

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c |   76 ++++++++++++++++++++++++++-------------------------
 1 file changed, 40 insertions(+), 36 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:42:56.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:42:57.000000000 +1000
@@ -1618,7 +1618,7 @@ static void compute_block_2(struct strip
 }
 
 static void
-handle_write_operations5(struct stripe_head *sh, struct stripe_head_state *s,
+schedule_reconstruction5(struct stripe_head *sh, struct stripe_head_state *s,
 			 int rcw, int expand)
 {
 	int i, pd_idx = sh->pd_idx, disks = sh->disks;
@@ -1783,7 +1783,7 @@ static int stripe_to_pdidx(sector_t stri
 }
 
 static void
-handle_requests_to_failed_array(raid5_conf_t *conf, struct stripe_head *sh,
+handle_failed_stripe(raid5_conf_t *conf, struct stripe_head *sh,
 				struct stripe_head_state *s, int disks,
 				struct bio **return_bi)
 {
@@ -1874,23 +1874,28 @@ handle_requests_to_failed_array(raid5_co
 			md_wakeup_thread(conf->mddev->thread);
 }
 
-/* __handle_issuing_new_read_requests5 - returns 0 if there are no more disks
- * to process
+/* fetch_block5 - checks the given member device to see if its data needs
+ * to be read or computed to satisfy a request.
+ *
+ * Returns 1 when no more member devices need to be checked, otherwise returns
+ * 0 to tell the loop in handle_stripe_fill5 to continue
  */
-static int __handle_issuing_new_read_requests5(struct stripe_head *sh,
-			struct stripe_head_state *s, int disk_idx, int disks)
+static int fetch_block5(struct stripe_head *sh, struct stripe_head_state *s,
+			int disk_idx, int disks)
 {
 	struct r5dev *dev = &sh->dev[disk_idx];
 	struct r5dev *failed_dev = &sh->dev[s->failed_num];
 
 	/* is the data in this block needed, and can we get it? */
 	if (!test_bit(R5_LOCKED, &dev->flags) &&
-	    !test_bit(R5_UPTODATE, &dev->flags) && (dev->toread ||
-	    (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
-	     s->syncing || s->expanding || (s->failed &&
-	     (failed_dev->toread || (failed_dev->towrite &&
-	     !test_bit(R5_OVERWRITE, &failed_dev->flags)
-	     ))))) {
+	    !test_bit(R5_UPTODATE, &dev->flags) &&
+	    (dev->toread ||
+	     (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
+	     s->syncing || s->expanding ||
+	     (s->failed &&
+	      (failed_dev->toread ||
+	       (failed_dev->towrite &&
+		!test_bit(R5_OVERWRITE, &failed_dev->flags)))))) {
 		/* We would like to get this block, possibly by computing it,
 		 * otherwise read it if the backing disk is insync
 		 */
@@ -1908,7 +1913,7 @@ static int __handle_issuing_new_read_req
 			 * subsequent operation.
 			 */
 			s->uptodate++;
-			return 0; /* uptodate + compute == disks */
+			return 1; /* uptodate + compute == disks */
 		} else if (test_bit(R5_Insync, &dev->flags)) {
 			set_bit(R5_LOCKED, &dev->flags);
 			set_bit(R5_Wantread, &dev->flags);
@@ -1918,10 +1923,13 @@ static int __handle_issuing_new_read_req
 		}
 	}
 
-	return ~0;
+	return 0;
 }
 
-static void handle_issuing_new_read_requests5(struct stripe_head *sh,
+/**
+ * handle_stripe_fill5 - read or compute data to satisfy pending requests.
+ */
+static void handle_stripe_fill5(struct stripe_head *sh,
 			struct stripe_head_state *s, int disks)
 {
 	int i;
@@ -1931,16 +1939,14 @@ static void handle_issuing_new_read_requ
 	 * midst of changing due to a write
 	 */
 	if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
-	    !sh->reconstruct_state) {
+	    !sh->reconstruct_state)
 		for (i = disks; i--; )
-			if (__handle_issuing_new_read_requests5(
-				sh, s, i, disks) == 0)
+			if (fetch_block5(sh, s, i, disks))
 				break;
-	}
 	set_bit(STRIPE_HANDLE, &sh->state);
 }
 
-static void handle_issuing_new_read_requests6(struct stripe_head *sh,
+static void handle_stripe_fill6(struct stripe_head *sh,
 			struct stripe_head_state *s, struct r6_state *r6s,
 			int disks)
 {
@@ -1999,12 +2005,12 @@ static void handle_issuing_new_read_requ
 }
 
 
-/* handle_completed_write_requests
+/* handle_stripe_clean_event
  * any written block on an uptodate or failed drive can be returned.
  * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
  * never LOCKED, so we don't need to test 'failed' directly.
  */
-static void handle_completed_write_requests(raid5_conf_t *conf,
+static void handle_stripe_clean_event(raid5_conf_t *conf,
 	struct stripe_head *sh, int disks, struct bio **return_bi)
 {
 	int i;
@@ -2049,7 +2055,7 @@ static void handle_completed_write_reque
 			md_wakeup_thread(conf->mddev->thread);
 }
 
-static void handle_issuing_new_write_requests5(raid5_conf_t *conf,
+static void handle_stripe_dirtying5(raid5_conf_t *conf,
 		struct stripe_head *sh,	struct stripe_head_state *s, int disks)
 {
 	int rmw = 0, rcw = 0, i;
@@ -2136,10 +2142,10 @@ static void handle_issuing_new_write_req
 	if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
 	    (s->locked == 0 && (rcw == 0 || rmw == 0) &&
 	    !test_bit(STRIPE_BIT_DELAY, &sh->state)))
-		handle_write_operations5(sh, s, rcw == 0, 0);
+		schedule_reconstruction5(sh, s, rcw == 0, 0);
 }
 
-static void handle_issuing_new_write_requests6(raid5_conf_t *conf,
+static void handle_stripe_dirtying6(raid5_conf_t *conf,
 		struct stripe_head *sh,	struct stripe_head_state *s,
 		struct r6_state *r6s, int disks)
 {
@@ -2597,8 +2603,7 @@ static void handle_stripe5(struct stripe
 	 * need to be failed
 	 */
 	if (s.failed > 1 && s.to_read+s.to_write+s.written)
-		handle_requests_to_failed_array(conf, sh, &s, disks,
-						&return_bi);
+		handle_failed_stripe(conf, sh, &s, disks, &return_bi);
 	if (s.failed > 1 && s.syncing) {
 		md_done_sync(conf->mddev, STRIPE_SECTORS,0);
 		clear_bit(STRIPE_SYNCING, &sh->state);
@@ -2614,7 +2619,7 @@ static void handle_stripe5(struct stripe
 	       !test_bit(R5_LOCKED, &dev->flags) &&
 	       test_bit(R5_UPTODATE, &dev->flags)) ||
 	       (s.failed == 1 && s.failed_num == sh->pd_idx)))
-		handle_completed_write_requests(conf, sh, disks, &return_bi);
+		handle_stripe_clean_event(conf, sh, disks, &return_bi);
 
 	/* Now we might consider reading some blocks, either to check/generate
 	 * parity, or to satisfy requests
@@ -2622,7 +2627,7 @@ static void handle_stripe5(struct stripe
 	 */
 	if (s.to_read || s.non_overwrite ||
 	    (s.syncing && (s.uptodate + s.compute < disks)) || s.expanding)
-		handle_issuing_new_read_requests5(sh, &s, disks);
+		handle_stripe_fill5(sh, &s, disks);
 
 	/* Now we check to see if any write operations have recently
 	 * completed
@@ -2666,7 +2671,7 @@ static void handle_stripe5(struct stripe
 	 *    block.
 	 */
 	if (s.to_write && !sh->reconstruct_state && !sh->check_state)
-		handle_issuing_new_write_requests5(conf, sh, &s, disks);
+		handle_stripe_dirtying5(conf, sh, &s, disks);
 
 	/* maybe we need to check and possibly fix the parity for this stripe
 	 * Any reads will already have been scheduled, so we just see if enough
@@ -2722,7 +2727,7 @@ static void handle_stripe5(struct stripe
 		sh->disks = conf->raid_disks;
 		sh->pd_idx = stripe_to_pdidx(sh->sector, conf,
 			conf->raid_disks);
-		handle_write_operations5(sh, &s, 1, 1);
+		schedule_reconstruction5(sh, &s, 1, 1);
 	} else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
 		clear_bit(STRIPE_EXPAND_READY, &sh->state);
 		atomic_dec(&conf->reshape_stripes);
@@ -2854,8 +2859,7 @@ static void handle_stripe6(struct stripe
 	 * might need to be failed
 	 */
 	if (s.failed > 2 && s.to_read+s.to_write+s.written)
-		handle_requests_to_failed_array(conf, sh, &s, disks,
-						&return_bi);
+		handle_failed_stripe(conf, sh, &s, disks, &return_bi);
 	if (s.failed > 2 && s.syncing) {
 		md_done_sync(conf->mddev, STRIPE_SECTORS,0);
 		clear_bit(STRIPE_SYNCING, &sh->state);
@@ -2880,7 +2884,7 @@ static void handle_stripe6(struct stripe
 	     ( r6s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
 			     && !test_bit(R5_LOCKED, &qdev->flags)
 			     && test_bit(R5_UPTODATE, &qdev->flags)))))
-		handle_completed_write_requests(conf, sh, disks, &return_bi);
+		handle_stripe_clean_event(conf, sh, disks, &return_bi);
 
 	/* Now we might consider reading some blocks, either to check/generate
 	 * parity, or to satisfy requests
@@ -2888,11 +2892,11 @@ static void handle_stripe6(struct stripe
 	 */
 	if (s.to_read || s.non_overwrite || (s.to_write && s.failed) ||
 	    (s.syncing && (s.uptodate < disks)) || s.expanding)
-		handle_issuing_new_read_requests6(sh, &s, &r6s, disks);
+		handle_stripe_fill6(sh, &s, &r6s, disks);
 
 	/* now to consider writing and what else, if anything should be read */
 	if (s.to_write)
-		handle_issuing_new_write_requests6(conf, sh, &s, &r6s, disks);
+		handle_stripe_dirtying6(conf, sh, &s, &r6s, disks);
 
 	/* maybe we need to check and possibly fix the parity for this stripe
 	 * Any reads will already have been scheduled, so we just see if enough

[PATCH 029 of 29] md: md: rationalize raid5 function names

[NeilBrown]

From: Dan Williams <dan.j.williams@intel.com>

Commit a4456856 refactored some of the deep code paths in raid5.c into separate
functions.  The names chosen at the time do not consistently indicate what is
going to happen to the stripe.  So, update the names, and since a stripe is a
cache element use cache semantics like fill, dirty, and clean.

(also, fix up the indentation in fetch_block5)

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/md/raid5.c |   76 ++++++++++++++++++++++++++-------------------------
 1 file changed, 40 insertions(+), 36 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c	2008-06-27 16:42:56.000000000 +1000
+++ ./drivers/md/raid5.c	2008-06-27 16:42:57.000000000 +1000
@@ -1618,7 +1618,7 @@ static void compute_block_2(struct strip
 }
 
 static void
-handle_write_operations5(struct stripe_head *sh, struct stripe_head_state *s,
+schedule_reconstruction5(struct stripe_head *sh, struct stripe_head_state *s,
 			 int rcw, int expand)
 {
 	int i, pd_idx = sh->pd_idx, disks = sh->disks;
@@ -1783,7 +1783,7 @@ static int stripe_to_pdidx(sector_t stri
 }
 
 static void
-handle_requests_to_failed_array(raid5_conf_t *conf, struct stripe_head *sh,
+handle_failed_stripe(raid5_conf_t *conf, struct stripe_head *sh,
 				struct stripe_head_state *s, int disks,
 				struct bio **return_bi)
 {
@@ -1874,23 +1874,28 @@ handle_requests_to_failed_array(raid5_co
 			md_wakeup_thread(conf->mddev->thread);
 }
 
-/* __handle_issuing_new_read_requests5 - returns 0 if there are no more disks
- * to process
+/* fetch_block5 - checks the given member device to see if its data needs
+ * to be read or computed to satisfy a request.
+ *
+ * Returns 1 when no more member devices need to be checked, otherwise returns
+ * 0 to tell the loop in handle_stripe_fill5 to continue
  */
-static int __handle_issuing_new_read_requests5(struct stripe_head *sh,
-			struct stripe_head_state *s, int disk_idx, int disks)
+static int fetch_block5(struct stripe_head *sh, struct stripe_head_state *s,
+			int disk_idx, int disks)
 {
 	struct r5dev *dev = &sh->dev[disk_idx];
 	struct r5dev *failed_dev = &sh->dev[s->failed_num];
 
 	/* is the data in this block needed, and can we get it? */
 	if (!test_bit(R5_LOCKED, &dev->flags) &&
-	    !test_bit(R5_UPTODATE, &dev->flags) && (dev->toread ||
-	    (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
-	     s->syncing || s->expanding || (s->failed &&
-	     (failed_dev->toread || (failed_dev->towrite &&
-	     !test_bit(R5_OVERWRITE, &failed_dev->flags)
-	     ))))) {
+	    !test_bit(R5_UPTODATE, &dev->flags) &&
+	    (dev->toread ||
+	     (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
+	     s->syncing || s->expanding ||
+	     (s->failed &&
+	      (failed_dev->toread ||
+	       (failed_dev->towrite &&
+		!test_bit(R5_OVERWRITE, &failed_dev->flags)))))) {
 		/* We would like to get this block, possibly by computing it,
 		 * otherwise read it if the backing disk is insync
 		 */
@@ -1908,7 +1913,7 @@ static int __handle_issuing_new_read_req
 			 * subsequent operation.
 			 */
 			s->uptodate++;
-			return 0; /* uptodate + compute == disks */
+			return 1; /* uptodate + compute == disks */
 		} else if (test_bit(R5_Insync, &dev->flags)) {
 			set_bit(R5_LOCKED, &dev->flags);
 			set_bit(R5_Wantread, &dev->flags);
@@ -1918,10 +1923,13 @@ static int __handle_issuing_new_read_req
 		}
 	}
 
-	return ~0;
+	return 0;
 }
 
-static void handle_issuing_new_read_requests5(struct stripe_head *sh,
+/**
+ * handle_stripe_fill5 - read or compute data to satisfy pending requests.
+ */
+static void handle_stripe_fill5(struct stripe_head *sh,
 			struct stripe_head_state *s, int disks)
 {
 	int i;
@@ -1931,16 +1939,14 @@ static void handle_issuing_new_read_requ
 	 * midst of changing due to a write
 	 */
 	if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
-	    !sh->reconstruct_state) {
+	    !sh->reconstruct_state)
 		for (i = disks; i--; )
-			if (__handle_issuing_new_read_requests5(
-				sh, s, i, disks) == 0)
+			if (fetch_block5(sh, s, i, disks))
 				break;
-	}
 	set_bit(STRIPE_HANDLE, &sh->state);
 }
 
-static void handle_issuing_new_read_requests6(struct stripe_head *sh,
+static void handle_stripe_fill6(struct stripe_head *sh,
 			struct stripe_head_state *s, struct r6_state *r6s,
 			int disks)
 {
@@ -1999,12 +2005,12 @@ static void handle_issuing_new_read_requ
 }
 
 
-/* handle_completed_write_requests
+/* handle_stripe_clean_event
  * any written block on an uptodate or failed drive can be returned.
  * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
  * never LOCKED, so we don't need to test 'failed' directly.
  */
-static void handle_completed_write_requests(raid5_conf_t *conf,
+static void handle_stripe_clean_event(raid5_conf_t *conf,
 	struct stripe_head *sh, int disks, struct bio **return_bi)
 {
 	int i;
@@ -2049,7 +2055,7 @@ static void handle_completed_write_reque
 			md_wakeup_thread(conf->mddev->thread);
 }
 
-static void handle_issuing_new_write_requests5(raid5_conf_t *conf,
+static void handle_stripe_dirtying5(raid5_conf_t *conf,
 		struct stripe_head *sh,	struct stripe_head_state *s, int disks)
 {
 	int rmw = 0, rcw = 0, i;
@@ -2136,10 +2142,10 @@ static void handle_issuing_new_write_req
 	if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
 	    (s->locked == 0 && (rcw == 0 || rmw == 0) &&
 	    !test_bit(STRIPE_BIT_DELAY, &sh->state)))
-		handle_write_operations5(sh, s, rcw == 0, 0);
+		schedule_reconstruction5(sh, s, rcw == 0, 0);
 }
 
-static void handle_issuing_new_write_requests6(raid5_conf_t *conf,
+static void handle_stripe_dirtying6(raid5_conf_t *conf,
 		struct stripe_head *sh,	struct stripe_head_state *s,
 		struct r6_state *r6s, int disks)
 {
@@ -2597,8 +2603,7 @@ static void handle_stripe5(struct stripe
 	 * need to be failed
 	 */
 	if (s.failed > 1 && s.to_read+s.to_write+s.written)
-		handle_requests_to_failed_array(conf, sh, &s, disks,
-						&return_bi);
+		handle_failed_stripe(conf, sh, &s, disks, &return_bi);
 	if (s.failed > 1 && s.syncing) {
 		md_done_sync(conf->mddev, STRIPE_SECTORS,0);
 		clear_bit(STRIPE_SYNCING, &sh->state);
@@ -2614,7 +2619,7 @@ static void handle_stripe5(struct stripe
 	       !test_bit(R5_LOCKED, &dev->flags) &&
 	       test_bit(R5_UPTODATE, &dev->flags)) ||
 	       (s.failed == 1 && s.failed_num == sh->pd_idx)))
-		handle_completed_write_requests(conf, sh, disks, &return_bi);
+		handle_stripe_clean_event(conf, sh, disks, &return_bi);
 
 	/* Now we might consider reading some blocks, either to check/generate
 	 * parity, or to satisfy requests
@@ -2622,7 +2627,7 @@ static void handle_stripe5(struct stripe
 	 */
 	if (s.to_read || s.non_overwrite ||
 	    (s.syncing && (s.uptodate + s.compute < disks)) || s.expanding)
-		handle_issuing_new_read_requests5(sh, &s, disks);
+		handle_stripe_fill5(sh, &s, disks);
 
 	/* Now we check to see if any write operations have recently
 	 * completed
@@ -2666,7 +2671,7 @@ static void handle_stripe5(struct stripe
 	 *    block.
 	 */
 	if (s.to_write && !sh->reconstruct_state && !sh->check_state)
-		handle_issuing_new_write_requests5(conf, sh, &s, disks);
+		handle_stripe_dirtying5(conf, sh, &s, disks);
 
 	/* maybe we need to check and possibly fix the parity for this stripe
 	 * Any reads will already have been scheduled, so we just see if enough
@@ -2722,7 +2727,7 @@ static void handle_stripe5(struct stripe
 		sh->disks = conf->raid_disks;
 		sh->pd_idx = stripe_to_pdidx(sh->sector, conf,
 			conf->raid_disks);
-		handle_write_operations5(sh, &s, 1, 1);
+		schedule_reconstruction5(sh, &s, 1, 1);
 	} else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
 		clear_bit(STRIPE_EXPAND_READY, &sh->state);
 		atomic_dec(&conf->reshape_stripes);
@@ -2854,8 +2859,7 @@ static void handle_stripe6(struct stripe
 	 * might need to be failed
 	 */
 	if (s.failed > 2 && s.to_read+s.to_write+s.written)
-		handle_requests_to_failed_array(conf, sh, &s, disks,
-						&return_bi);
+		handle_failed_stripe(conf, sh, &s, disks, &return_bi);
 	if (s.failed > 2 && s.syncing) {
 		md_done_sync(conf->mddev, STRIPE_SECTORS,0);
 		clear_bit(STRIPE_SYNCING, &sh->state);
@@ -2880,7 +2884,7 @@ static void handle_stripe6(struct stripe
 	     ( r6s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
 			     && !test_bit(R5_LOCKED, &qdev->flags)
 			     && test_bit(R5_UPTODATE, &qdev->flags)))))
-		handle_completed_write_requests(conf, sh, disks, &return_bi);
+		handle_stripe_clean_event(conf, sh, disks, &return_bi);
 
 	/* Now we might consider reading some blocks, either to check/generate
 	 * parity, or to satisfy requests
@@ -2888,11 +2892,11 @@ static void handle_stripe6(struct stripe
 	 */
 	if (s.to_read || s.non_overwrite || (s.to_write && s.failed) ||
 	    (s.syncing && (s.uptodate < disks)) || s.expanding)
-		handle_issuing_new_read_requests6(sh, &s, &r6s, disks);
+		handle_stripe_fill6(sh, &s, &r6s, disks);
 
 	/* now to consider writing and what else, if anything should be read */
 	if (s.to_write)
-		handle_issuing_new_write_requests6(conf, sh, &s, &r6s, disks);
+		handle_stripe_dirtying6(conf, sh, &s, &r6s, disks);
 
 	/* maybe we need to check and possibly fix the parity for this stripe
 	 * Any reads will already have been scheduled, so we just see if enough

Re: [PATCH 008 of 29] md: Close race in md_probe

[Andre Noll]

[-- Attachment #1: Type: text/plain, Size: 2566 bytes --]

On 16:50, NeilBrown wrote:
> 
> There is a possible race in md_probe.  If two threads call md_probe
> for the same device, then one could exit (having checked that
> ->gendisk exists) before the other has called kobject_init_and_add,
> thus returning an incomplete kobj which will cause problems when
> we try to add children to it.
> 
> So extend the range of protection of disks_mutex slightly to
> avoid this possibility.
> 
> Signed-off-by: Neil Brown <neilb@suse.de>
> 
> ### Diffstat output
>  ./drivers/md/md.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff .prev/drivers/md/md.c ./drivers/md/md.c
> --- .prev/drivers/md/md.c	2008-06-27 15:31:27.000000000 +1000
> +++ ./drivers/md/md.c	2008-06-27 15:31:35.000000000 +1000
> @@ -3359,9 +3359,9 @@ static struct kobject *md_probe(dev_t de
>  	disk->queue = mddev->queue;
>  	add_disk(disk);
>  	mddev->gendisk = disk;
> -	mutex_unlock(&disks_mutex);
>  	error = kobject_init_and_add(&mddev->kobj, &md_ktype, &disk->dev.kobj,
>  				     "%s", "md");
> +	mutex_unlock(&disks_mutex);
>  	if (error)
>  		printk(KERN_WARNING "md: cannot register %s/md - name in use\n",
>  		       disk->disk_name);

Even with this patch, md_probe() calls mddev_find() without holding
the disks_mutex. Is this OK? If it isn't, something like the patch
below might be necessary.

Andre
---

From: Andre Noll <maan@systemlinux.org>

Fix possible race in md_probe().

The current code calls mddev_find() without any locks held.  It might
happen that mddev_find() succeeds but the returned mddev pointer
becomes stale just before the disks_mutex is aquired.

So close the race by calling mddev_find() with the disks mutex held.

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 647395b..6cb8773 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3184,17 +3184,20 @@ static int mdp_major;
 static struct kobject *md_probe(dev_t dev, int *part, void *data)
 {
 	static DEFINE_MUTEX(disks_mutex);
-	mddev_t *mddev = mddev_find(dev);
+	mddev_t *mddev;
 	struct gendisk *disk;
 	int partitioned = (MAJOR(dev) != MD_MAJOR);
 	int shift = partitioned ? MdpMinorShift : 0;
 	int unit = MINOR(dev) >> shift;
 	int error;
 
-	if (!mddev)
-		return NULL;
 
 	mutex_lock(&disks_mutex);
+	mddev = mddev_find(dev);
+	if (!mddev) {
+		mutex_unlock(&disks_mutex);
+		return NULL;
+	}
 	if (mddev->gendisk) {
 		mutex_unlock(&disks_mutex);
 		mddev_put(mddev);

-- 
The only person who always got his work done by Friday was Robinson Crusoe

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 189 bytes --]

Re: [PATCH 018 of 29] md: Support changing rdev size on running arrays.

[Markus Hochholdinger]

[-- Attachment #1: Type: text/plain, Size: 6322 bytes --]

Hi,

Am Freitag, 27. Juni 2008 08:51 schrieb NeilBrown:
> From: Chris Webb <chris@arachsys.com>
> Allow /sys/block/mdX/md/rdY/size to change on running arrays, moving the
> superblock if necessary for this metadata version. We prevent the available
> space from shrinking to less than the used size, and allow it to be set to
> zero to fill all the available space on the underlying device.

I'm very happy of this new feature. But I'm a little confused how to use it 
correctly.
Can md now recognize the change by itself and I only have to run mdadm --grow? 
Or have I manually update /sys/block/mdX/md/rdY/size and afterwards run 
mdadm --grow?

To be on the safe side I'd first lvresize one disk of the raid1, then do 
mdadm --grow to let md update/move the superblock of this disk. And after 
this is successful, lvresize the other disk and do mdadm --grow. So in case 
of a failure i wouldn't loose the whole raid1!?
Am I correct or am I missing something?


> Signed-off-by: Chris Webb <chris@arachsys.com>
> Signed-off-by: Neil Brown <neilb@suse.de>
>
> ### Diffstat output
>  ./drivers/md/md.c |  100
> ++++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 87
> insertions(+), 13 deletions(-)
>
> diff .prev/drivers/md/md.c ./drivers/md/md.c
> --- .prev/drivers/md/md.c	2008-06-27 16:22:03.000000000 +1000
> +++ ./drivers/md/md.c	2008-06-27 16:22:03.000000000 +1000
> @@ -658,11 +658,14 @@ static unsigned int calc_sb_csum(mdp_sup
>   */
>
>  struct super_type  {
> -	char 		*name;
> -	struct module	*owner;
> -	int		(*load_super)(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int
> minor_version); -	int		(*validate_super)(mddev_t *mddev, mdk_rdev_t *rdev);
> -	void		(*sync_super)(mddev_t *mddev, mdk_rdev_t *rdev);
> +	char		    *name;
> +	struct module	    *owner;
> +	int		    (*load_super)(mdk_rdev_t *rdev, mdk_rdev_t *refdev,
> +					  int minor_version);
> +	int		    (*validate_super)(mddev_t *mddev, mdk_rdev_t *rdev);
> +	void		    (*sync_super)(mddev_t *mddev, mdk_rdev_t *rdev);
> +	unsigned long long  (*rdev_size_change)(mdk_rdev_t *rdev,
> +						unsigned long long size);
>  };
>
>  /*
> @@ -1004,6 +1007,27 @@ static void super_90_sync(mddev_t *mddev
>  }
>
>  /*
> + * rdev_size_change for 0.90.0
> + */
> +static unsigned long long
> +super_90_rdev_size_change(mdk_rdev_t *rdev, unsigned long long size)
> +{
> +	if (size && size < rdev->mddev->size)
> +		return 0; /* component must fit device */
> +	size *= 2; /* convert to sectors */
> +	if (rdev->mddev->bitmap_offset)
> +		return 0; /* can't move bitmap */
> +	rdev->sb_offset = calc_dev_sboffset(rdev->bdev);
> +	if (!size || size > rdev->sb_offset*2)
> +		size = rdev->sb_offset*2;
> +	md_super_write(rdev->mddev, rdev, rdev->sb_offset << 1, rdev->sb_size,
> +		       rdev->sb_page);
> +	md_super_wait(rdev->mddev);
> +	return size/2; /* kB for sysfs */
> +}
> +
> +
> +/*
>   * version 1 superblock
>   */
>
> @@ -1328,21 +1352,59 @@ static void super_1_sync(mddev_t *mddev,
>  	sb->sb_csum = calc_sb_1_csum(sb);
>  }
>
> +static unsigned long long
> +super_1_rdev_size_change(mdk_rdev_t *rdev, unsigned long long size)
> +{
> +	struct mdp_superblock_1 *sb;
> +	unsigned long long max_size;
> +	if (size && size < rdev->mddev->size)
> +		return 0; /* component must fit device */
> +	size *= 2; /* convert to sectors */
> +	if (rdev->sb_offset < rdev->data_offset/2) {
> +		/* minor versions 1 and 2; superblock before data */
> +		max_size = (rdev->bdev->bd_inode->i_size >> 9);
> +		max_size -= rdev->data_offset;
> +		if (!size || size > max_size)
> +			size = max_size;
> +	} else if (rdev->mddev->bitmap_offset) {
> +		/* minor version 0 with bitmap we can't move */
> +		return 0;
> +	} else {
> +		/* minor version 0; superblock after data */
> +		sector_t sb_offset;
> +		sb_offset = (rdev->bdev->bd_inode->i_size >> 9) - 8*2;
> +		sb_offset &= ~(sector_t)(4*2 - 1);
> +		max_size = rdev->size*2 + sb_offset - rdev->sb_offset*2;
> +		if (!size || size > max_size)
> +			size = max_size;
> +		rdev->sb_offset = sb_offset/2;
> +	}
> +	sb = (struct mdp_superblock_1 *) page_address(rdev->sb_page);
> +	sb->data_size = cpu_to_le64(size);
> +	sb->super_offset = rdev->sb_offset*2;
> +	sb->sb_csum = calc_sb_1_csum(sb);
> +	md_super_write(rdev->mddev, rdev, rdev->sb_offset << 1, rdev->sb_size,
> +		       rdev->sb_page);
> +	md_super_wait(rdev->mddev);
> +	return size/2; /* kB for sysfs */
> +}
>
>  static struct super_type super_types[] = {
>  	[0] = {
>  		.name	= "0.90.0",
>  		.owner	= THIS_MODULE,
> -		.load_super	= super_90_load,
> -		.validate_super	= super_90_validate,
> -		.sync_super	= super_90_sync,
> +		.load_super	    = super_90_load,
> +		.validate_super	    = super_90_validate,
> +		.sync_super	    = super_90_sync,
> +		.rdev_size_change   = super_90_rdev_size_change,
>  	},
>  	[1] = {
>  		.name	= "md-1",
>  		.owner	= THIS_MODULE,
> -		.load_super	= super_1_load,
> -		.validate_super	= super_1_validate,
> -		.sync_super	= super_1_sync,
> +		.load_super	    = super_1_load,
> +		.validate_super	    = super_1_validate,
> +		.sync_super	    = super_1_sync,
> +		.rdev_size_change   = super_1_rdev_size_change,
>  	},
>  };
>
> @@ -2060,8 +2122,20 @@ rdev_size_store(mdk_rdev_t *rdev, const
>
>  	if (e==buf || (*e && *e != '\n'))
>  		return -EINVAL;
> -	if (my_mddev->pers && rdev->raid_disk >= 0)
> -		return -EBUSY;
> +	if (my_mddev->pers && rdev->raid_disk >= 0) {
> +		if (rdev->mddev->persistent) {
> +			size = super_types[rdev->mddev->major_version].
> +				rdev_size_change(rdev, size);
> +			if (!size)
> +				return -EBUSY;
> +		} else if (!size) {
> +			size = (rdev->bdev->bd_inode->i_size >> 10);
> +			size -= rdev->data_offset/2;
> +		}
> +		if (size < rdev->mddev->size)
> +			return -EINVAL; /* component must fit device */
> +	}
> +
>  	rdev->size = size;
>  	if (size > oldsize && rdev->mddev->external) {
>  		/* need to check that all other rdevs with the same ->bdev
> --
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

-- 
greetings

eMHa

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Re: [PATCH 008 of 29] md: Close race in md_probe

[Neil Brown]

On Friday June 27, maan@systemlinux.org wrote:
> On 16:50, NeilBrown wrote:
> > 
> > There is a possible race in md_probe.  If two threads call md_probe
> > for the same device, then one could exit (having checked that
> > ->gendisk exists) before the other has called kobject_init_and_add,
> > thus returning an incomplete kobj which will cause problems when
> > we try to add children to it.
...
> 
> Even with this patch, md_probe() calls mddev_find() without holding
> the disks_mutex. Is this OK? If it isn't, something like the patch
> below might be necessary.

Thanks for looking at this and asking.

No, the below patch is not necessary.

mddev_find gets a reference on the mddev, so it cannot become stale.
md_probe does not return what it gets from mddev_find until getting
the disks_mutex lock and checking the contents, so it is sure to
return a good mddev.

Thanks,
NeilBrown



> 
> Andre
> ---
> 
> From: Andre Noll <maan@systemlinux.org>
> 
> Fix possible race in md_probe().
> 
> The current code calls mddev_find() without any locks held.  It might
> happen that mddev_find() succeeds but the returned mddev pointer
> becomes stale just before the disks_mutex is aquired.
> 
> So close the race by calling mddev_find() with the disks mutex held.
> 
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 647395b..6cb8773 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -3184,17 +3184,20 @@ static int mdp_major;
>  static struct kobject *md_probe(dev_t dev, int *part, void *data)
>  {
>  	static DEFINE_MUTEX(disks_mutex);
> -	mddev_t *mddev = mddev_find(dev);
> +	mddev_t *mddev;
>  	struct gendisk *disk;
>  	int partitioned = (MAJOR(dev) != MD_MAJOR);
>  	int shift = partitioned ? MdpMinorShift : 0;
>  	int unit = MINOR(dev) >> shift;
>  	int error;
>  
> -	if (!mddev)
> -		return NULL;
>  
>  	mutex_lock(&disks_mutex);
> +	mddev = mddev_find(dev);
> +	if (!mddev) {
> +		mutex_unlock(&disks_mutex);
> +		return NULL;
> +	}
>  	if (mddev->gendisk) {
>  		mutex_unlock(&disks_mutex);
>  		mddev_put(mddev);
> 
> -- 
> The only person who always got his work done by Friday was Robinson Crusoe

Re: [PATCH 018 of 29] md: Support changing rdev size on running arrays.

[Neil Brown]

On Friday June 27, Markus@hochholdinger.net wrote:
> Hi,
> 
> Am Freitag, 27. Juni 2008 08:51 schrieb NeilBrown:
> > From: Chris Webb <chris@arachsys.com>
> > Allow /sys/block/mdX/md/rdY/size to change on running arrays, moving the
> > superblock if necessary for this metadata version. We prevent the available
> > space from shrinking to less than the used size, and allow it to be set to
> > zero to fill all the available space on the underlying device.
> 
> I'm very happy of this new feature. But I'm a little confused how to use it 
> correctly.
> Can md now recognize the change by itself and I only have to run mdadm --grow? 
> Or have I manually update /sys/block/mdX/md/rdY/size and afterwards run 
> mdadm --grow?

No, md does not recognise the change by itself.
Currently you need to update ..../size yourself before using 
   "mdadm --grow"
This should probably be incorporated into mdadm at some stage, but it
hasn't yet.

> 
> To be on the safe side I'd first lvresize one disk of the raid1, then do 
> mdadm --grow to let md update/move the superblock of this disk. And after 
> this is successful, lvresize the other disk and do mdadm --grow. So in case 
> of a failure i wouldn't loose the whole raid1!?
> Am I correct or am I missing something?

You don't want to "mdadm --grow" until everything has been resized.
First lvresize one disk, then write '0' to the .../size file.
Then do the same for the other disk.
Then "mdadm --grow /dev/mdX --size max".

NeilBrown

Re: [PATCH 008 of 29] md: Close race in md_probe

[Andre Noll]

[-- Attachment #1: Type: text/plain, Size: 396 bytes --]

On 09:38, Neil Brown wrote:

> mddev_find gets a reference on the mddev, so it cannot become stale.
> md_probe does not return what it gets from mddev_find until getting
> the disks_mutex lock and checking the contents, so it is sure to
> return a good mddev.

I see. Thanks for the clarification.

Andre
-- 
The only person who always got his work done by Friday was Robinson Crusoe

[-- Attachment #2: Digital signature --]
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Re: [PATCH 001 of 29] md: Ensure interrupted recovery completed properly (v1 metadata plus bitmap)

[Jan Engelhardt]

On Friday 2008-06-27 08:49, NeilBrown wrote:
>
>[...] In this case it tells recovery to ignore the bitmap
>and recovery all blocks.
>
>So without this fix, a raid1 ir raid4/5/6 array with version 1.x
>metadata and a write intent bitmaps, that is stopped in the middle
>of a recovery, will appear to complete the recovery instantly
>after it is reassembled, but the recovery will not be correct.

If the array is stopped in the middle of a recovery, should not
it restart recovery where it left off when reassembled?
That's what the write intent bitmap is for, is not it? Like..

wait_for(assemble)
for_all('1' bits in bitmap)
    if (resync == success)
        bitmap[pos] = '0';
    if (signalled)
        break;

and stopping the resync in the middle, the bitmap should still
have '1' bits left to be processed on the next assemble.
Or, where did I go wrong?

Re: [PATCH 018 of 29] md: Support changing rdev size on running arrays.

[Markus Hochholdinger]

[-- Attachment #1: Type: text/plain, Size: 3698 bytes --]

Hello,

Am 28.06.2008 um 01:41 Uhr schrieb Neil Brown <neilb@suse.de>:
> On Friday June 27, Markus@hochholdinger.net wrote:
> > Am Freitag, 27. Juni 2008 08:51 schrieb NeilBrown:
> > > From: Chris Webb <chris@arachsys.com>
> > > Allow /sys/block/mdX/md/rdY/size to change on running arrays, moving
> > > the superblock if necessary for this metadata version. We prevent the
> > > available space from shrinking to less than the used size, and allow it
> > > to be set to zero to fill all the available space on the underlying
> > > device.
> > I'm very happy of this new feature. But I'm a little confused how to use
> > it correctly.
> > Can md now recognize the change by itself and I only have to run mdadm
> > --grow? Or have I manually update /sys/block/mdX/md/rdY/size and
> > afterwards run mdadm --grow?
> No, md does not recognise the change by itself.
> Currently you need to update ..../size yourself before using
>    "mdadm --grow"
> This should probably be incorporated into mdadm at some stage, but it
> hasn't yet.

it's some time ago but today i'm able to test this (because now i have a xen 
kernel which recognizes size changes).
I tested with metadata version 0.9, 1.0 and 1.1 but didn't get it to work. I 
create a raid1:
mdadm --create /dev/md1 --level=1 --raid-disks=2 --metadata=1.0 /dev/xvda1 /dev/xvdb1

Then I change the size of xvda1 and get the following kernel message:
[ 3281.905317] Setting capacity to 4194304
[ 3281.905317] xvda1: detected capacity change from 1073741824 to 2147483648

After this i do:
echo "0" > /sys/block/md1/md/rd0/size
No kernel message so far and
  cat /sys/block/md1/md/rd0/size
still shows 1048570.

Then the same for xvdb1.

And then I tried to grow md1 in the hope it will somehow detect the new size 
correct, but i only get a very little grow:
[ 3345.133882] md1: detected capacity change from 1073729536 to 1073735680
[ 3345.140087] md: resync of RAID array md1
[ 3345.140098] md: minimum _guaranteed_  speed: 1000 KB/sec/disk.
[ 3345.140105] md: using maximum available idle IO bandwidth (but not more 
than 200000 KB/sec) for resync.
[ 3345.140121] md: using 128k window, over a total of 1048570 blocks.
[ 3345.140129] md: resuming resync of md1 from checkpoint.
[ 3345.140412] md: md1: resync done.
[ 3345.160064] RAID1 conf printout:
[ 3345.160071]  --- wd:2 rd:2
[ 3345.160076]  disk 0, wo:0, o:1, dev:xvda1
[ 3345.160081]  disk 1, wo:0, o:1, dev:xvdb1

Especially "md1: detected capacity change from 1073729536 to 1073735680" makes 
me wonder.


I also tried to set values to /sys/block/md1/md/rd1/size, but all i got was
  echo: write error: Invalid argument

And the output of /sys/block/md1/md/rd1/size never changes.


> > To be on the safe side I'd first lvresize one disk of the raid1, then do
> > mdadm --grow to let md update/move the superblock of this disk. And after
> > this is successful, lvresize the other disk and do mdadm --grow. So in
> > case of a failure i wouldn't loose the whole raid1!?
> > Am I correct or am I missing something?
> You don't want to "mdadm --grow" until everything has been resized.
> First lvresize one disk, then write '0' to the .../size file.
> Then do the same for the other disk.
> Then "mdadm --grow /dev/mdX --size max".

I tried mdadm version 3.0.3 and 3.1.1. Is it possible that something has 
changed inside mdadm?
I used kernel 2.6.32-4-xen-amd64 (debian squeeze).

Are am I doing something wrong? Has something changed so i'm on the wrong way? 
Is there another way to do online grow of an raid1 without full resync? 
Anyone any ideas?

Many thanks in advance.


-- 
greetings

eMHa

[-- Attachment #2: This is a digitally signed message part. --]
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Re: [PATCH 018 of 29] md: Support changing rdev size on running arrays.

[Neil Brown]

On Tue, 30 Mar 2010 16:52:13 +0200
Markus Hochholdinger <Markus@hochholdinger.net> wrote:

> Hello,
> 
> Am 28.06.2008 um 01:41 Uhr schrieb Neil Brown <neilb@suse.de>:
> > On Friday June 27, Markus@hochholdinger.net wrote:
> > > Am Freitag, 27. Juni 2008 08:51 schrieb NeilBrown:
> > > > From: Chris Webb <chris@arachsys.com>
> > > > Allow /sys/block/mdX/md/rdY/size to change on running arrays, moving
> > > > the superblock if necessary for this metadata version. We prevent the
> > > > available space from shrinking to less than the used size, and allow it
> > > > to be set to zero to fill all the available space on the underlying
> > > > device.
> > > I'm very happy of this new feature. But I'm a little confused how to use
> > > it correctly.
> > > Can md now recognize the change by itself and I only have to run mdadm
> > > --grow? Or have I manually update /sys/block/mdX/md/rdY/size and
> > > afterwards run mdadm --grow?
> > No, md does not recognise the change by itself.
> > Currently you need to update ..../size yourself before using
> >    "mdadm --grow"
> > This should probably be incorporated into mdadm at some stage, but it
> > hasn't yet.
> 
> it's some time ago but today i'm able to test this (because now i have a xen 
> kernel which recognizes size changes).
> I tested with metadata version 0.9, 1.0 and 1.1 but didn't get it to work. I 
> create a raid1:
> mdadm --create /dev/md1 --level=1 --raid-disks=2 --metadata=1.0 /dev/xvda1 /dev/xvdb1
> 
> Then I change the size of xvda1 and get the following kernel message:
> [ 3281.905317] Setting capacity to 4194304
> [ 3281.905317] xvda1: detected capacity change from 1073741824 to 2147483648
> 
> After this i do:
> echo "0" > /sys/block/md1/md/rd0/size
> No kernel message so far and
>   cat /sys/block/md1/md/rd0/size
> still shows 1048570.

That is very odd.  The number printed out in the "detected capacity change"
line is exactly the name that should be used when you write to "md/rd0/size".

You could try
   strace echo 0 > /sys/block/md1/md/rd0/size

to be sure there is no error return.
And maybe
   blockdev --getsz /dev/xvda1
and
   blockdev --getsz /dev/xvda

to double check that the block size looks right.

Are you sure the message didn't say "xvda: detected capacity change...", and
you still need to change the size of the partition?

NeilBrown


> 
> Then the same for xvdb1.
> 
> And then I tried to grow md1 in the hope it will somehow detect the new size 
> correct, but i only get a very little grow:
> [ 3345.133882] md1: detected capacity change from 1073729536 to 1073735680
> [ 3345.140087] md: resync of RAID array md1
> [ 3345.140098] md: minimum _guaranteed_  speed: 1000 KB/sec/disk.
> [ 3345.140105] md: using maximum available idle IO bandwidth (but not more 
> than 200000 KB/sec) for resync.
> [ 3345.140121] md: using 128k window, over a total of 1048570 blocks.
> [ 3345.140129] md: resuming resync of md1 from checkpoint.
> [ 3345.140412] md: md1: resync done.
> [ 3345.160064] RAID1 conf printout:
> [ 3345.160071]  --- wd:2 rd:2
> [ 3345.160076]  disk 0, wo:0, o:1, dev:xvda1
> [ 3345.160081]  disk 1, wo:0, o:1, dev:xvdb1
> 
> Especially "md1: detected capacity change from 1073729536 to 1073735680" makes 
> me wonder.
> 
> 
> I also tried to set values to /sys/block/md1/md/rd1/size, but all i got was
>   echo: write error: Invalid argument
> 
> And the output of /sys/block/md1/md/rd1/size never changes.

That is very odd.
> 
> 
> > > To be on the safe side I'd first lvresize one disk of the raid1, then do
> > > mdadm --grow to let md update/move the superblock of this disk. And after
> > > this is successful, lvresize the other disk and do mdadm --grow. So in
> > > case of a failure i wouldn't loose the whole raid1!?
> > > Am I correct or am I missing something?
> > You don't want to "mdadm --grow" until everything has been resized.
> > First lvresize one disk, then write '0' to the .../size file.
> > Then do the same for the other disk.
> > Then "mdadm --grow /dev/mdX --size max".
> 
> I tried mdadm version 3.0.3 and 3.1.1. Is it possible that something has 
> changed inside mdadm?
> I used kernel 2.6.32-4-xen-amd64 (debian squeeze).
> 
> Are am I doing something wrong? Has something changed so i'm on the wrong way? 
> Is there another way to do online grow of an raid1 without full resync? 
> Anyone any ideas?
> 
> Many thanks in advance.
> 
> 

Re: [PATCH 018 of 29] md: Support changing rdev size on running arrays.

[Markus Hochholdinger]

[-- Attachment #1: Type: text/plain, Size: 8777 bytes --]

Hello,

Am 31.03.2010 um 07:41 Uhr schrieb Neil Brown <neilb@suse.de>:
> On Tue, 30 Mar 2010 16:52:13 +0200
> Markus Hochholdinger <Markus@hochholdinger.net> wrote:
> > Am 28.06.2008 um 01:41 Uhr schrieb Neil Brown <neilb@suse.de>:
> > > On Friday June 27, Markus@hochholdinger.net wrote:
> > > > Am Freitag, 27. Juni 2008 08:51 schrieb NeilBrown:
> > > > > From: Chris Webb <chris@arachsys.com>
[..]
> > Then I change the size of xvda1 and get the following kernel message:
> > [ 3281.905317] Setting capacity to 4194304
> > [ 3281.905317] xvda1: detected capacity change from 1073741824 to
> > 2147483648
> > After this i do:
> > echo "0" > /sys/block/md1/md/rd0/size
> > No kernel message so far and
> >   cat /sys/block/md1/md/rd0/size
> > still shows 1048570.
> That is very odd.  The number printed out in the "detected capacity change"
> line is exactly the name that should be used when you write to
> "md/rd0/size".

it's good to hear this isn't normal, so the error must be on my side.

OK, from the beginning:
# dd if=/dev/zero of=/dev/xvda1 bs=16M
# dd if=/dev/zero of=/dev/xvdb1 bs=16M
# blockdev --getsz /dev/xvda1
4194304
# blockdev --getsz /dev/xvdb1
4194304
# 
mdadm --create /dev/md1 --raid-disks=2 --level=1 --metadata=0.9 /dev/xvda1 /dev/xvdb1
[  715.153257] md: bind<xvda1>
[  715.156154] md: bind<xvdb1>
[  715.192298] raid1: md1 is not clean -- starting background reconstruction
[  715.192298] raid1: raid set md1 active with 2 out of 2 mirrors
[  715.192320] md1: detected capacity change from 0 to 2147418112
mdadm: array /dev/md1 started.
[  715.197762]  md1: unknown partition table

=> resize xvda1 to 3GB

Here i need to say that the new size will show up until someone asks for the 
new size! I've done this with "fdisk -l". But now i see:
# blockdev --getsz /dev/xvda1
4194304
# fdisk -l /dev/xvda1
[  867.124950] Setting capacity to 6291456
[  867.124950] xvda1: detected capacity change from 2147483648 to 3221225472

Disk /dev/xvda1: 3221 MB, 3221225472 bytes
255 heads, 63 sectors/track, 391 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000

Disk /dev/xvda1 doesn't contain a valid partition table
# blockdev --getsz /dev/xvda1
6291456


For me it seems the "blockdev --getsz" was cached somehow.


> You could try
>    strace echo 0 > /sys/block/md1/md/rd0/size
# strace echo 0 > /sys/block/md1/md/rd0/size
execve("/bin/echo", ["echo", "0"], [/* 26 vars */]) = 0
brk(0)                                  = 0x2352000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 
0x7f5b648c8000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or 
directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 
0x7f5b648c6000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or 
directory)
open("/etc/ld.so.cache", O_RDONLY)      = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=15141, ...}) = 0
mmap(NULL, 15141, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f5b648c2000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or 
directory)
open("/lib/libc.so.6", O_RDONLY)        = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\320\353\1\0\0\0\0\0"..., 
832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1379752, ...}) = 0
mmap(NULL, 3487784, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 
0x7f5b64359000
mprotect(0x7f5b644a3000, 2097152, PROT_NONE) = 0
mmap(0x7f5b646a3000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|
MAP_DENYWRITE, 3, 0x14a000) = 0x7f5b646a3000
mmap(0x7f5b646a8000, 18472, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|
MAP_ANONYMOUS, -1, 0) = 0x7f5b646a8000
close(3)                                = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 
0x7f5b648c1000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 
0x7f5b648c0000
arch_prctl(ARCH_SET_FS, 0x7f5b648c06f0) = 0
mprotect(0x7f5b646a3000, 16384, PROT_READ) = 0
mprotect(0x7f5b648c9000, 4096, PROT_READ) = 0
munmap(0x7f5b648c2000, 15141)           = 0
brk(0)                                  = 0x2352000
brk(0x2373000)                          = 0x2373000
open("/usr/lib/locale/locale-archive", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=3519008, ...}) = 0
mmap(NULL, 3519008, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f5b63ffd000
close(3)                                = 0
fstat(1, {st_mode=S_IFREG|0644, st_size=4096, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 
0x7f5b648c5000
write(1, "0\n", 2)                      = -1 EINVAL (Invalid argument)
close(1)                                = 0
munmap(0x7f5b648c5000, 4096)            = 0
open("/usr/share/locale/locale.alias", O_RDONLY) = 1
fstat(1, {st_mode=S_IFREG|0644, st_size=2570, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 
0x7f5b648c5000
read(1, "# Locale name alias data base.\n#"..., 4096) = 2570
read(1, "", 4096)                       = 0
close(1)                                = 0
munmap(0x7f5b648c5000, 4096)            = 0
open("/usr/share/locale/en_US.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 
ENOENT (No such file or directory)
open("/usr/share/locale/en_US/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT 
(No such file or directory)
open("/usr/share/locale/en.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 
ENOENT (No such file or directory)
open("/usr/share/locale/en/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT 
(No such file or directory)
write(2, "echo: ", 6echo: )                   = 6
write(2, "write error", 11write error)             = 11
open("/usr/share/locale/en_US.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT 
(No such file or directory)
open("/usr/share/locale/en_US/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No 
such file or directory)
open("/usr/share/locale/en.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT 
(No such file or directory)
open("/usr/share/locale/en/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No 
such file or directory)
write(2, ": Invalid argument", 18: Invalid argument)      = 18
write(2, "\n", 1
)                       = 1
exit_group(1)                           = ?
# echo $?
1
# cat /sys/block/md1/md/rd0/size 
2097088


> to be sure there is no error return.

Hm, there seems to be some error, but i don't get it what it is.


> And maybe
>    blockdev --getsz /dev/xvda1

# blockdev --getsz /dev/xvda1
6291456


> and
>    blockdev --getsz /dev/xvda

There is no xvda! I use Xen and i can assign a logical volume directly to 
xvda1, so i don't have to put a partition table on this block device! Perhaps 
this is the error!?


> to double check that the block size looks right.

Yeah, the block size looks right.


> Are you sure the message didn't say "xvda: detected capacity change...",
> and you still need to change the size of the partition?

Yes, i'm sure and i used copy&paste, so no write error here. There is no xvda 
because i can assign a logical volume direct to xvda1 inside my virtual xen 
machine.

So i try to use partitions, assigning hole disks (xvdc and xvdd) to md1 
doesn't work also. But with partitions i have the problem that 
after "resizing" the partition, my partition xvdc1 seems to be not grown from 
the view of the linux system:
# blockdev --getsz /dev/xvdc1
2088387
# blockdev --getsz /dev/xvdc
4194304
# fdisk -l /dev/xvdc

Disk /dev/xvdc: 2147 MB, 2147483648 bytes
255 heads, 63 sectors/track, 261 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000

    Device Boot      Start         End      Blocks   Id  System
/dev/xvdc1               1         261     2096451   fd  Linux raid autodetect


Is it possible that this raid1 grow only works with lvm?

Another note to
  echo 0 > /sys/block/md1/md/rd0/size
The first time after a grow it works only once, giving a return code of 0 and 
no error message. And after that it will return:
# echo 0 > /sys/block/md1/md/rd0/size
-bash: echo: write error: Invalid argument
# echo $?
1

Is this supposed to work only once (after a grow)? But also if it has a return 
code of 0 the value of /sys/block/md1/md/rd0/size doesn't change. Still 
puzzled...

Which superblock version should i use for this grow? My live servers all have 
0.9 so i first try this with 0.9. But if you say this will only work with 
1.0, 1.1 or 1.2 i'll try all this with this specific superblock version.

Any further ideas what i can try?

Many thanks in advance.


-- 
greetings

eMHa

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Re: [PATCH 018 of 29] md: Support changing rdev size on running arrays.

[Markus Hochholdinger]

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Hello,

it's been a long time, but today I tried again and had success!

Am 28.06.2008 um 01:41 Uhr schrieb Neil Brown <neilb@suse.de>:
> On Friday June 27, Markus@hochholdinger.net wrote:
> > Am Freitag, 27. Juni 2008 08:51 schrieb NeilBrown:
> > > From: Chris Webb <chris@arachsys.com>
[..]
> You don't want to "mdadm --grow" until everything has been resized.
> First lvresize one disk, then write '0' to the .../size file.
> Then do the same for the other disk.
> Then "mdadm --grow /dev/mdX --size max".

it works for me, if I do:
  echo 0 > /sys/block/md2/md/rd0/size
  mdadm --grow /dev/md2 --size=max
  # till here, nothing happens
  echo 0 > /sys/block/md2/md/rd1/size
  mdadm --grow /dev/md2 --size=max
  # rebuild of the added space begins

If I do only:
  echo 0 > /sys/block/md2/md/rd0/size
  echo 0 > /sys/block/md2/md/rd1/size
  mdadm --grow /dev/md2 --size=max
nothing will change.

As I understand, with "echo 0" md sees the new size and only with --grow the 
superblock will be moved.

I'm doing this with 2.6.32-5-xen-686 within Debian (squeeze) 6.0.

Many thanks to you and all the other linux-raid developers for this feature!

I'm very happy about this :-)


-- 
greetings

eMHa

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Re: [PATCH 018 of 29] md: Support changing rdev size on running arrays.

[NeilBrown]

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On Sat, 24 Mar 2012 21:47:15 +0100 Markus Hochholdinger
<Markus@hochholdinger.net> wrote:

> Hello,
> 
> it's been a long time, but today I tried again and had success!
> 
> Am 28.06.2008 um 01:41 Uhr schrieb Neil Brown <neilb@suse.de>:
> > On Friday June 27, Markus@hochholdinger.net wrote:
> > > Am Freitag, 27. Juni 2008 08:51 schrieb NeilBrown:
> > > > From: Chris Webb <chris@arachsys.com>
> [..]
> > You don't want to "mdadm --grow" until everything has been resized.
> > First lvresize one disk, then write '0' to the .../size file.
> > Then do the same for the other disk.
> > Then "mdadm --grow /dev/mdX --size max".
> 
> it works for me, if I do:
>   echo 0 > /sys/block/md2/md/rd0/size
>   mdadm --grow /dev/md2 --size=max
>   # till here, nothing happens
>   echo 0 > /sys/block/md2/md/rd1/size
>   mdadm --grow /dev/md2 --size=max
>   # rebuild of the added space begins
> 
> If I do only:
>   echo 0 > /sys/block/md2/md/rd0/size
>   echo 0 > /sys/block/md2/md/rd1/size
>   mdadm --grow /dev/md2 --size=max
> nothing will change.

That is odd.. it certainly should.

And the current 'mdadm' will do the "echo 0 > size" for you so you just need
to "mdadm --grow  --size=max" command.

> 
> As I understand, with "echo 0" md sees the new size and only with --grow the 
> superblock will be moved.

No, the superblock is moved with the "echo 0", but the space isn't used until
the "--grow".


> 
> I'm doing this with 2.6.32-5-xen-686 within Debian (squeeze) 6.0.
> 
> Many thanks to you and all the other linux-raid developers for this feature!
> 
> I'm very happy about this :-)

Excellent!

Thanks,
NeilBrown


> 
> 


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Re: [PATCH 018 of 29] md: Support changing rdev size on running arrays.

[Markus Hochholdinger]

Hi,

Am Samstag, 24. März 2012, 21:47:15 CET schrieb Markus Hochholdinger:
> it's been a long time, but today I tried again and had success!
> Am 28.06.2008 um 01:41 Uhr schrieb Neil Brown <neilb@suse.de>:
> > On Friday June 27, Markus@hochholdinger.net wrote:
> > > Am Freitag, 27. Juni 2008 08:51 schrieb NeilBrown:
> > > > From: Chris Webb <chris@arachsys.com>
> [..]
> > You don't want to "mdadm --grow" until everything has been resized.
> > First lvresize one disk, then write '0' to the .../size file.
> > Then do the same for the other disk.
> > Then "mdadm --grow /dev/mdX --size max".
> it works for me, if I do:
>   echo 0 > /sys/block/md2/md/rd0/size
>   mdadm --grow /dev/md2 --size=max
>   # till here, nothing happens
>   echo 0 > /sys/block/md2/md/rd1/size
>   mdadm --grow /dev/md2 --size=max
>   # rebuild of the added space begins

This has been working for me till at least kernel 4.19.x and I first recognized  
it not working anymore with kernel 5.10.x . So inbetween something changed 
regarding the resize and grow of md raid1 with superblock version 1.0.
The grow still works and a rebuild is done, but afterwards the superblock 
isn't created/moved to the new end of the devices. The raid1 works until you 
stop it, but you won't be able to re-assemble it (re-creating works). While 
re-creating I recognized the grown filesystem (after the raid1 was grown) was 
too large (fsck complained).

I already tracked it down to the version of the metadata/superblock. With 
version 1.0 (superblock at the end) the above fails and it looks like the 
superblock on the grown device is somehow there but with wrong informations 
(mdadm --zero-superblock has removed something while mdadm -D .. tells me, 
there's no superblock).

All works fine with superblock version 1.2 (superblock at the beginning).

Any ideas what could have changed so the grow feature for raid1 with 
superblock version 1.0 isn't working anymore?

For now the workaround is to really remove a grown device from the raid1 and 
do a full rebuild before re-adding the other grown device.

I'll test the different kernel versions to see, where/when this feature was 
lost.


> If I do only:
>   echo 0 > /sys/block/md2/md/rd0/size
>   echo 0 > /sys/block/md2/md/rd1/size
>   mdadm --grow /dev/md2 --size=max
> nothing will change.
> As I understand, with "echo 0" md sees the new size and only with --grow the
> superblock will be moved.
> I'm doing this with 2.6.32-5-xen-686 within Debian (squeeze) 6.0.
> Many thanks to you and all the other linux-raid developers for this feature!
> I'm very happy about this :-)


-- 
Mfg

Markus Hochholdinger

Re: [PATCH 018 of 29] md: Support changing rdev size on running arrays.

[Markus Hochholdinger]

Hi,

Am Mittwoch, 10. November 2021, 14:09:53 CET schrieb Markus Hochholdinger:
> Am Samstag, 24. März 2012, 21:47:15 CET schrieb Markus Hochholdinger:
> > it's been a long time, but today I tried again and had success!
> > Am 28.06.2008 um 01:41 Uhr schrieb Neil Brown <neilb@suse.de>:
> > > On Friday June 27, Markus@hochholdinger.net wrote:
> > > > Am Freitag, 27. Juni 2008 08:51 schrieb NeilBrown:
> > > > > From: Chris Webb <chris@arachsys.com>
> > [..]
> > > You don't want to "mdadm --grow" until everything has been resized.
> > > First lvresize one disk, then write '0' to the .../size file.
> > > Then do the same for the other disk.
> > > Then "mdadm --grow /dev/mdX --size max".
> > it works for me, if I do:
> >   echo 0 > /sys/block/md2/md/rd0/size
> >   mdadm --grow /dev/md2 --size=max
> >   # till here, nothing happens
> >   echo 0 > /sys/block/md2/md/rd1/size
> >   mdadm --grow /dev/md2 --size=max
> >   # rebuild of the added space begins
> This has been working for me till at least kernel 4.19.x and I first
> recognized it not working anymore with kernel 5.10.x . So inbetween
> something changed regarding the resize and grow of md raid1 with superblock
> version 1.0. The grow still works and a rebuild is done, but afterwards the
> superblock isn't created/moved to the new end of the devices. The raid1
> works until you stop it, but you won't be able to re-assemble it
> (re-creating works). While re-creating I recognized the grown filesystem
> (after the raid1 was grown) was too large (fsck complained).
> I already tracked it down to the version of the metadata/superblock. With
> version 1.0 (superblock at the end) the above fails and it looks like the
> superblock on the grown device is somehow there but with wrong informations
> (mdadm --zero-superblock has removed something while mdadm -D .. tells me,
> there's no superblock).
> All works fine with superblock version 1.2 (superblock at the beginning).
> Any ideas what could have changed so the grow feature for raid1 with
> superblock version 1.0 isn't working anymore?
> For now the workaround is to really remove a grown device from the raid1 and
> do a full rebuild before re-adding the other grown device.
> I'll test the different kernel versions to see, where/when this feature was
> lost.

It is working es (I) expected till at least kernel 5.4.158.

It is not working with 5.10.x till 5.15.1.

On my old systems (kernel <= 5.4.x) after resizing one component
  mdadm -E /dev/xvda2
is able to see the moved superblock only after
  echo 0 > /sys/block/md2/md/rd0/size

On new systems (kernel >= 5.10.0) it doesn't matter if I issue
  echo 0 > /sys/block/md2/md/rd0/size
mdadm -E keeps complaining about no superblock on the grown device.
(The bitmap was removed before the echo 0 and I tried to remove the bitmap at 
all before resizing, still the same issue.)

It's only possible to remove the changed device and add with a full rebuild. 
But this isn't possible, if both devices were resized before. mdadm complains 
about no metadata available, no matter what I do while the md raid1 is still 
running (where is the superblock updated on the disks then?).


> > If I do only:
> >   echo 0 > /sys/block/md2/md/rd0/size
> >   echo 0 > /sys/block/md2/md/rd1/size
> >   mdadm --grow /dev/md2 --size=max
> > 
> > nothing will change.
> > As I understand, with "echo 0" md sees the new size and only with --grow
> > the superblock will be moved.
> > I'm doing this with 2.6.32-5-xen-686 within Debian (squeeze) 6.0.
> > Many thanks to you and all the other linux-raid developers for this
> > feature! I'm very happy about this :-)


-- 
Mfg

Markus Hochholdinger

Re: [PATCH 018 of 29] md: Support changing rdev size on running arrays.

[Markus Hochholdinger]

Hi,

Am Mittwoch, 10. November 2021, 18:51:19 CET schrieb Markus Hochholdinger:
> It is working es (I) expected till at least kernel 5.4.158.
> It is not working with 5.10.x till 5.15.1.

it is working with
  5.8.18
and is not working with
  5.9.16

Currently I'm looking into the diff md.c between these two kernel versions to 
find the error (I'll try to figure this out):

@@ -2184,13 +2212,22 @@ super_1_rdev_size_change(struct md_rdev *rdev, 
sector_t num_sectors)
                return 0;
        } else {
                /* minor version 0; superblock after data */
-               sector_t sb_start;
-               sb_start = (i_size_read(rdev->bdev->bd_inode) >> 9) - 8*2;
+               sector_t sb_start, bm_space;
+               sector_t dev_size = i_size_read(rdev->bdev->bd_inode) >> 9;
+
+               /* 8K is for superblock */
+               sb_start = dev_size - 8*2;
                sb_start &= ~(sector_t)(4*2 - 1);
-               max_sectors = rdev->sectors + sb_start - rdev->sb_start;
+
+               bm_space = super_1_choose_bm_space(dev_size);
+
+               /* Space that can be used to store date needs to decrease
+                * superblock bitmap space and bad block space(4K)
+                */
+               max_sectors = sb_start - bm_space - 4*2;
+
                if (!num_sectors || num_sectors > max_sectors)
                        num_sectors = max_sectors;
-               rdev->sb_start = sb_start;
        }
        sb = page_address(rdev->sb_page);
        sb->data_size = cpu_to_le64(num_sectors);


-- 
Mfg

Markus Hochholdinger

Re: [PATCH 018 of 29] md: Support changing rdev size on running arrays.

[Markus Hochholdinger]

It's possible, I've found the error:
  rdev->sb_start = sb_start;
is missing within md.c within /* minor version 0; superblock after data */
From my understanding, this means the new calculated superblock position isn't 
used.

I changed:
--- a/drivers/md/md.c    2021-09-30 08:11:08.000000000 +0000
+++ b/drivers/md/md.c     2021-11-11 14:54:10.535633028 +0000
@@ -2252,6 +2252,7 @@
 
                if (!num_sectors || num_sectors > max_sectors)
                        num_sectors = max_sectors;
+               rdev->sb_start = sb_start;
        }
        sb = page_address(rdev->sb_page);
        sb->data_size = cpu_to_le64(num_sectors);

I tested it with 5.10.46 and resizing with superblock version 1.0 is now 
working for me.

If this is correct, how can I get this into longterm 5.10.x and the current 
kernel upstream?

Many thanks in advance.


-- 
Mfg

Markus Hochholdinger

Re: [PATCH 018 of 29] md: Support changing rdev size on running arrays.

[Guoqing Jiang]

On 11/11/21 11:09 PM, Markus Hochholdinger wrote:
> It's possible, I've found the error:
>    rdev->sb_start = sb_start;
> is missing within md.c within /* minor version 0; superblock after data */
>  From my understanding, this means the new calculated superblock position isn't
> used.
>
> I changed:
> --- a/drivers/md/md.c    2021-09-30 08:11:08.000000000 +0000
> +++ b/drivers/md/md.c     2021-11-11 14:54:10.535633028 +0000
> @@ -2252,6 +2252,7 @@
>   
>                  if (!num_sectors || num_sectors > max_sectors)
>                          num_sectors = max_sectors;
> +               rdev->sb_start = sb_start;
>          }
>          sb = page_address(rdev->sb_page);
>          sb->data_size = cpu_to_le64(num_sectors);
>
> I tested it with 5.10.46 and resizing with superblock version 1.0 is now
> working for me.
>
> If this is correct, how can I get this into longterm 5.10.x and the current
> kernel upstream?

Please refer to submitting-patches.rst and stable-kernel-rules.rst which 
are under
Documentation.

And I think this tag need to be added in your patch.

Fixes: commit d9c0fa509eaf ("md: fix max sectors calculation for super 1.0")

Thanks,
Guoqing

Re: [PATCH 018 of 29] md: Support changing rdev size on running arrays.

[Markus Hochholdinger]

Am Freitag, 12. November 2021, 09:22:26 CET schrieb Guoqing Jiang:
> On 11/11/21 11:09 PM, Markus Hochholdinger wrote:
> > It's possible, I've found the error:
> >    rdev->sb_start = sb_start;
> > is missing within md.c within /* minor version 0; superblock after data */
> >  From my understanding, this means the new calculated superblock position
> >  isn't> 
> > used.
> > I changed:
> > --- a/drivers/md/md.c    2021-09-30 08:11:08.000000000 +0000
> > +++ b/drivers/md/md.c     2021-11-11 14:54:10.535633028 +0000
> > @@ -2252,6 +2252,7 @@
> >                  if (!num_sectors || num_sectors > max_sectors)
> >                          num_sectors = max_sectors;
> > +               rdev->sb_start = sb_start;
> >          }
> >          sb = page_address(rdev->sb_page);
> >          sb->data_size = cpu_to_le64(num_sectors);
> > I tested it with 5.10.46 and resizing with superblock version 1.0 is now
> > working for me.
> > If this is correct, how can I get this into longterm 5.10.x and the
> > current
> > kernel upstream?
> Please refer to submitting-patches.rst and stable-kernel-rules.rst which
> are under
> Documentation.
> And I think this tag need to be added in your patch.
> Fixes: commit d9c0fa509eaf ("md: fix max sectors calculation for super 1.0")

Many thanks, this was very helpful for me.


-- 
Mfg

Markus Hochholdinger