[PATCH 0/3] btrfs: Move btrfs_raid_array to public

[PATCH 0/3] btrfs: Move btrfs_raid_array to public

[Zhao Lei]

This array is used to record attributes of each raid type,
make it public, and many functions will benifit with this array.

For example, num_tolerated_disk_barrier_failures(), we can
avoid complex conditions in this function, and get raid attribute
simply by accessing above array.

It can also make code logic simple, reduce duplication code, and
increase maintainability.

We can also add more raid attributes in this array, to make it
widely used.

Zhao Lei (3):
  btrfs: Move btrfs_raid_array to public
  btrfs: use btrfs_raid_array for
    btrfs_get_num_tolerated_disk_barrier_failures()
  btrfs: use btrfs_raid_array in btrfs_reduce_alloc_profile

 fs/btrfs/disk-io.c     |  35 ++++++++-----
 fs/btrfs/extent-tree.c |  48 ++++++++----------
 fs/btrfs/volumes.c     | 135 ++++++++++++++++++++++++++++---------------------
 fs/btrfs/volumes.h     |   5 ++
 4 files changed, 125 insertions(+), 98 deletions(-)

-- 
1.8.5.1

[PATCH 1/3] btrfs: Move btrfs_raid_array to public

[Zhao Lei]

This array is used to record attributes of each raid type,
make it public, and many functions will benifit with this array.

For example, num_tolerated_disk_barrier_failures(), we can
avoid complex conditions in this function, and get raid attribute
simply by accessing above array.

It can also make code logic simple, reduce duplication code, and
increase maintainability.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
---
 fs/btrfs/volumes.c | 128 +++++++++++++++++++++++++++++------------------------
 fs/btrfs/volumes.h |   4 ++
 2 files changed, 73 insertions(+), 59 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 6fc73586..2a65d2d 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -42,6 +42,75 @@
 #include "dev-replace.h"
 #include "sysfs.h"
 
+const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
+	[BTRFS_RAID_RAID10] = {
+		.sub_stripes	= 2,
+		.dev_stripes	= 1,
+		.devs_max	= 0,	/* 0 == as many as possible */
+		.devs_min	= 4,
+		.devs_increment	= 2,
+		.ncopies	= 2,
+	},
+	[BTRFS_RAID_RAID1] = {
+		.sub_stripes	= 1,
+		.dev_stripes	= 1,
+		.devs_max	= 2,
+		.devs_min	= 2,
+		.devs_increment	= 2,
+		.ncopies	= 2,
+	},
+	[BTRFS_RAID_DUP] = {
+		.sub_stripes	= 1,
+		.dev_stripes	= 2,
+		.devs_max	= 1,
+		.devs_min	= 1,
+		.devs_increment	= 1,
+		.ncopies	= 2,
+	},
+	[BTRFS_RAID_RAID0] = {
+		.sub_stripes	= 1,
+		.dev_stripes	= 1,
+		.devs_max	= 0,
+		.devs_min	= 2,
+		.devs_increment	= 1,
+		.ncopies	= 1,
+	},
+	[BTRFS_RAID_SINGLE] = {
+		.sub_stripes	= 1,
+		.dev_stripes	= 1,
+		.devs_max	= 1,
+		.devs_min	= 1,
+		.devs_increment	= 1,
+		.ncopies	= 1,
+	},
+	[BTRFS_RAID_RAID5] = {
+		.sub_stripes	= 1,
+		.dev_stripes	= 1,
+		.devs_max	= 0,
+		.devs_min	= 2,
+		.devs_increment	= 1,
+		.ncopies	= 2,
+	},
+	[BTRFS_RAID_RAID6] = {
+		.sub_stripes	= 1,
+		.dev_stripes	= 1,
+		.devs_max	= 0,
+		.devs_min	= 3,
+		.devs_increment	= 1,
+		.ncopies	= 3,
+	},
+};
+
+const u64 const btrfs_raid_group[BTRFS_NR_RAID_TYPES] = {
+	[BTRFS_RAID_RAID10] = BTRFS_BLOCK_GROUP_RAID10,
+	[BTRFS_RAID_RAID1]  = BTRFS_BLOCK_GROUP_RAID1,
+	[BTRFS_RAID_DUP]    = BTRFS_BLOCK_GROUP_DUP,
+	[BTRFS_RAID_RAID0]  = BTRFS_BLOCK_GROUP_RAID0,
+	[BTRFS_RAID_SINGLE] = 0,
+	[BTRFS_RAID_RAID5]  = BTRFS_BLOCK_GROUP_RAID5,
+	[BTRFS_RAID_RAID6]  = BTRFS_BLOCK_GROUP_RAID6,
+};
+
 static int init_first_rw_device(struct btrfs_trans_handle *trans,
 				struct btrfs_root *root,
 				struct btrfs_device *device);
@@ -4285,65 +4354,6 @@ static int btrfs_cmp_device_info(const void *a, const void *b)
 	return 0;
 }
 
-static const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
-	[BTRFS_RAID_RAID10] = {
-		.sub_stripes	= 2,
-		.dev_stripes	= 1,
-		.devs_max	= 0,	/* 0 == as many as possible */
-		.devs_min	= 4,
-		.devs_increment	= 2,
-		.ncopies	= 2,
-	},
-	[BTRFS_RAID_RAID1] = {
-		.sub_stripes	= 1,
-		.dev_stripes	= 1,
-		.devs_max	= 2,
-		.devs_min	= 2,
-		.devs_increment	= 2,
-		.ncopies	= 2,
-	},
-	[BTRFS_RAID_DUP] = {
-		.sub_stripes	= 1,
-		.dev_stripes	= 2,
-		.devs_max	= 1,
-		.devs_min	= 1,
-		.devs_increment	= 1,
-		.ncopies	= 2,
-	},
-	[BTRFS_RAID_RAID0] = {
-		.sub_stripes	= 1,
-		.dev_stripes	= 1,
-		.devs_max	= 0,
-		.devs_min	= 2,
-		.devs_increment	= 1,
-		.ncopies	= 1,
-	},
-	[BTRFS_RAID_SINGLE] = {
-		.sub_stripes	= 1,
-		.dev_stripes	= 1,
-		.devs_max	= 1,
-		.devs_min	= 1,
-		.devs_increment	= 1,
-		.ncopies	= 1,
-	},
-	[BTRFS_RAID_RAID5] = {
-		.sub_stripes	= 1,
-		.dev_stripes	= 1,
-		.devs_max	= 0,
-		.devs_min	= 2,
-		.devs_increment	= 1,
-		.ncopies	= 2,
-	},
-	[BTRFS_RAID_RAID6] = {
-		.sub_stripes	= 1,
-		.dev_stripes	= 1,
-		.devs_max	= 0,
-		.devs_min	= 3,
-		.devs_increment	= 1,
-		.ncopies	= 3,
-	},
-};
-
 static u32 find_raid56_stripe_len(u32 data_devices, u32 dev_stripe_target)
 {
 	/* TODO allow them to set a preferred stripe size */
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 2ca784a..75d6083 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -338,6 +338,10 @@ struct btrfs_raid_attr {
 	int ncopies;		/* how many copies to data has */
 };
 
+extern const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES];
+
+extern const u64 btrfs_raid_group[BTRFS_NR_RAID_TYPES];
+
 struct map_lookup {
 	u64 type;
 	int io_align;
-- 
1.8.5.1

Re: [PATCH 1/3] btrfs: Move btrfs_raid_array to public

[David Sterba]

On Tue, Sep 15, 2015 at 09:08:06PM +0800, Zhao Lei wrote:
> This array is used to record attributes of each raid type,
> make it public, and many functions will benifit with this array.
> 
> For example, num_tolerated_disk_barrier_failures(), we can
> avoid complex conditions in this function, and get raid attribute
> simply by accessing above array.
> 
> It can also make code logic simple, reduce duplication code, and
> increase maintainability.
> 
> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>

Reviewed-by: David Sterba <dsterba@suse.com>

[PATCH 2/3] btrfs: use btrfs_raid_array for btrfs_get_num_tolerated_disk_barrier_failures()

[Zhao Lei]

btrfs_raid_array[] is used to define all raid attributes, use it
to get tolerated_failures in btrfs_get_num_tolerated_disk_barrier_failures(),
instead of complex condition in function.

It can make code simple and auto-support other possible raid-type in
future.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
---
 fs/btrfs/disk-io.c | 35 ++++++++++++++++++++++-------------
 fs/btrfs/volumes.c |  7 +++++++
 fs/btrfs/volumes.h |  1 +
 3 files changed, 30 insertions(+), 13 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 0d98aee..126baab 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3445,22 +3445,31 @@ static int barrier_all_devices(struct btrfs_fs_info *info)
 
 int btrfs_get_num_tolerated_disk_barrier_failures(u64 flags)
 {
-	if ((flags & (BTRFS_BLOCK_GROUP_DUP |
-		      BTRFS_BLOCK_GROUP_RAID0 |
-		      BTRFS_AVAIL_ALLOC_BIT_SINGLE)) ||
-	    ((flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0))
-		return 0;
+	int raid_type;
+	int min_tolerated = INT_MAX;
 
-	if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
-		     BTRFS_BLOCK_GROUP_RAID5 |
-		     BTRFS_BLOCK_GROUP_RAID10))
-		return 1;
+	if ((flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0 ||
+	    (flags & BTRFS_AVAIL_ALLOC_BIT_SINGLE))
+		min_tolerated = min(min_tolerated,
+				    btrfs_raid_array[BTRFS_RAID_SINGLE].
+				    tolerated_failures);
 
-	if (flags & BTRFS_BLOCK_GROUP_RAID6)
-		return 2;
+	for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
+		if (raid_type == BTRFS_RAID_SINGLE)
+			continue;
+		if (!(flags & btrfs_raid_group[raid_type]))
+			continue;
+		min_tolerated = min(min_tolerated,
+				    btrfs_raid_array[raid_type].
+				    tolerated_failures);
+	}
 
-	pr_warn("BTRFS: unknown raid type: %llu\n", flags);
-	return 0;
+	if (min_tolerated == INT_MAX) {
+		pr_warn("BTRFS: unknown raid flag: %llu\n", flags);
+		min_tolerated = 0;
+	}
+
+	return min_tolerated;
 }
 
 int btrfs_calc_num_tolerated_disk_barrier_failures(
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 2a65d2d..7b53390 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -48,6 +48,7 @@ const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
 		.dev_stripes	= 1,
 		.devs_max	= 0,	/* 0 == as many as possible */
 		.devs_min	= 4,
+		.tolerated_failures = 1,
 		.devs_increment	= 2,
 		.ncopies	= 2,
 	},
@@ -56,6 +57,7 @@ const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
 		.dev_stripes	= 1,
 		.devs_max	= 2,
 		.devs_min	= 2,
+		.tolerated_failures = 1,
 		.devs_increment	= 2,
 		.ncopies	= 2,
 	},
@@ -64,6 +66,7 @@ const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
 		.dev_stripes	= 2,
 		.devs_max	= 1,
 		.devs_min	= 1,
+		.tolerated_failures = 0,
 		.devs_increment	= 1,
 		.ncopies	= 2,
 	},
@@ -72,6 +75,7 @@ const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
 		.dev_stripes	= 1,
 		.devs_max	= 0,
 		.devs_min	= 2,
+		.tolerated_failures = 0,
 		.devs_increment	= 1,
 		.ncopies	= 1,
 	},
@@ -80,6 +84,7 @@ const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
 		.dev_stripes	= 1,
 		.devs_max	= 1,
 		.devs_min	= 1,
+		.tolerated_failures = 0,
 		.devs_increment	= 1,
 		.ncopies	= 1,
 	},
@@ -88,6 +93,7 @@ const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
 		.dev_stripes	= 1,
 		.devs_max	= 0,
 		.devs_min	= 2,
+		.tolerated_failures = 1,
 		.devs_increment	= 1,
 		.ncopies	= 2,
 	},
@@ -96,6 +102,7 @@ const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
 		.dev_stripes	= 1,
 		.devs_max	= 0,
 		.devs_min	= 3,
+		.tolerated_failures = 2,
 		.devs_increment	= 1,
 		.ncopies	= 3,
 	},
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 75d6083..04ff0ef 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -334,6 +334,7 @@ struct btrfs_raid_attr {
 	int dev_stripes;	/* stripes per dev */
 	int devs_max;		/* max devs to use */
 	int devs_min;		/* min devs needed */
+	int tolerated_failures; /* max tolerated fail devs */
 	int devs_increment;	/* ndevs has to be a multiple of this */
 	int ncopies;		/* how many copies to data has */
 };
-- 
1.8.5.1

Re: [PATCH 2/3] btrfs: use btrfs_raid_array for btrfs_get_num_tolerated_disk_barrier_failures()

[David Sterba]

On Tue, Sep 15, 2015 at 09:08:07PM +0800, Zhao Lei wrote:
> btrfs_raid_array[] is used to define all raid attributes, use it
> to get tolerated_failures in btrfs_get_num_tolerated_disk_barrier_failures(),
> instead of complex condition in function.
> 
> It can make code simple and auto-support other possible raid-type in
> future.
> 
> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>

Reviewed-by: David Sterba <dsterba@suse.com>

[PATCH 3/3] btrfs: use btrfs_raid_array in btrfs_reduce_alloc_profile

[Zhao Lei]

btrfs_raid_array[] holds attributes of all raid types.

Use btrfs_raid_array[].devs_min is best way for request
in btrfs_reduce_alloc_profile(), instead of use complex
condition of each raid types.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
---
 fs/btrfs/extent-tree.c | 48 ++++++++++++++++++++++--------------------------
 1 file changed, 22 insertions(+), 26 deletions(-)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 5411f0a..0d93cad 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3822,7 +3822,8 @@ static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
 {
 	u64 num_devices = root->fs_info->fs_devices->rw_devices;
 	u64 target;
-	u64 tmp;
+	u64 raid_type;
+	u64 allowed = 0;
 
 	/*
 	 * see if restripe for this chunk_type is in progress, if so
@@ -3840,31 +3841,26 @@ static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
 	spin_unlock(&root->fs_info->balance_lock);
 
 	/* First, mask out the RAID levels which aren't possible */
-	if (num_devices == 1)
-		flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0 |
-			   BTRFS_BLOCK_GROUP_RAID5);
-	if (num_devices < 3)
-		flags &= ~BTRFS_BLOCK_GROUP_RAID6;
-	if (num_devices < 4)
-		flags &= ~BTRFS_BLOCK_GROUP_RAID10;
-
-	tmp = flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
-		       BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID5 |
-		       BTRFS_BLOCK_GROUP_RAID6 | BTRFS_BLOCK_GROUP_RAID10);
-	flags &= ~tmp;
-
-	if (tmp & BTRFS_BLOCK_GROUP_RAID6)
-		tmp = BTRFS_BLOCK_GROUP_RAID6;
-	else if (tmp & BTRFS_BLOCK_GROUP_RAID5)
-		tmp = BTRFS_BLOCK_GROUP_RAID5;
-	else if (tmp & BTRFS_BLOCK_GROUP_RAID10)
-		tmp = BTRFS_BLOCK_GROUP_RAID10;
-	else if (tmp & BTRFS_BLOCK_GROUP_RAID1)
-		tmp = BTRFS_BLOCK_GROUP_RAID1;
-	else if (tmp & BTRFS_BLOCK_GROUP_RAID0)
-		tmp = BTRFS_BLOCK_GROUP_RAID0;
-
-	return extended_to_chunk(flags | tmp);
+	for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
+		if (num_devices >= btrfs_raid_array[raid_type].devs_min)
+			allowed |= btrfs_raid_group[raid_type];
+	}
+	allowed &= flags;
+
+	if (allowed & BTRFS_BLOCK_GROUP_RAID6)
+		allowed = BTRFS_BLOCK_GROUP_RAID6;
+	else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
+		allowed = BTRFS_BLOCK_GROUP_RAID5;
+	else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
+		allowed = BTRFS_BLOCK_GROUP_RAID10;
+	else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
+		allowed = BTRFS_BLOCK_GROUP_RAID1;
+	else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
+		allowed = BTRFS_BLOCK_GROUP_RAID0;
+
+	flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
+
+	return extended_to_chunk(flags | allowed);
 }
 
 static u64 get_alloc_profile(struct btrfs_root *root, u64 orig_flags)
-- 
1.8.5.1

Re: [PATCH 3/3] btrfs: use btrfs_raid_array in btrfs_reduce_alloc_profile

[David Sterba]

On Tue, Sep 15, 2015 at 09:08:08PM +0800, Zhao Lei wrote:
> btrfs_raid_array[] holds attributes of all raid types.
> 
> Use btrfs_raid_array[].devs_min is best way for request
> in btrfs_reduce_alloc_profile(), instead of use complex
> condition of each raid types.
> 
> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>

Reviewed-by: David Sterba <dsterba@suse.com>