diff mbox series

[RFC,ONLY,6/8] btrfs: add code to read raid extent

Message ID 2aa8aae2f6394b774f480d877f2701fed6fd74c4.1652711187.git.johannes.thumshirn@wdc.com (mailing list archive)
State New, archived
Headers show
Series btrfs: introduce raid-stripe-tree | expand

Commit Message

Johannes Thumshirn May 16, 2022, 2:31 p.m. UTC 
Add boilerplate code to lookup the physical address from the
raid-stripe-tree when a read on an RAID volume formatted with the
raid-stripe-tree was attempted.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 fs/btrfs/raid-stripe-tree.c | 68 +++++++++++++++++++++++++++++++++++++
 fs/btrfs/raid-stripe-tree.h |  3 ++
 fs/btrfs/volumes.c          | 23 +++++++++++--
 3 files changed, 91 insertions(+), 3 deletions(-)

Comments

Josef Bacik May 16, 2022, 2:55 p.m. UTC | #1 
On Mon, May 16, 2022 at 07:31:41AM -0700, Johannes Thumshirn wrote:
> Add boilerplate code to lookup the physical address from the
> raid-stripe-tree when a read on an RAID volume formatted with the
> raid-stripe-tree was attempted.
> 
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> ---
>  fs/btrfs/raid-stripe-tree.c | 68 +++++++++++++++++++++++++++++++++++++
>  fs/btrfs/raid-stripe-tree.h |  3 ++
>  fs/btrfs/volumes.c          | 23 +++++++++++--
>  3 files changed, 91 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/btrfs/raid-stripe-tree.c b/fs/btrfs/raid-stripe-tree.c
> index 370ea68fe343..ecc8205be760 100644
> --- a/fs/btrfs/raid-stripe-tree.c
> +++ b/fs/btrfs/raid-stripe-tree.c
> @@ -1,10 +1,78 @@
>  // SPDX-License-Identifier: GPL-2.0
>  
> +#include <linux/btrfs_tree.h>
> +
>  #include "ctree.h"
>  #include "transaction.h"
>  #include "disk-io.h"
>  #include "raid-stripe-tree.h"
>  #include "volumes.h"
> +#include "misc.h"
> +
> +int btrfs_get_raid_extent_offset(struct btrfs_fs_info *fs_info,
> +				 u64 logical, u64 length, u64 map_type,
> +				 u64 devid, u64 *physical)
> +{
> +	struct btrfs_root *stripe_root = fs_info->stripe_root;
> +	struct btrfs_dp_stripe *raid_stripe;
> +	struct btrfs_key stripe_key;
> +	struct btrfs_key found_key;
> +	struct btrfs_path *path;
> +	struct extent_buffer *leaf;
> +	u64 offset;
> +	u64 found_logical, found_length;
> +	int num_stripes;
> +	int slot;
> +	int ret;
> +	int i;
> +
> +	stripe_key.objectid = logical;
> +	stripe_key.type = BTRFS_RAID_STRIPE_KEY;
> +	stripe_key.offset = length;
> +
> +	path = btrfs_alloc_path();
> +	if (!path)
> +		return -ENOMEM;
> +
> +	num_stripes = btrfs_bg_type_to_factor(map_type);
> +
> +	ret = btrfs_search_slot_for_read(stripe_root, &stripe_key, path, 0, 0);
> +	if (ret < 0) {
> +		goto out;
> +	}
> +
> +	if (ret == 1)
> +		ret = 0;
> +
> +	while (1) {
> +		leaf = path->nodes[0];
> +		slot = path->slots[0];
> +
> +		btrfs_item_key_to_cpu(leaf, &found_key, slot);
> +		found_logical = found_key.objectid;
> +		found_length = found_key.offset;
> +
> +		if (!in_range(logical, found_logical, found_length))
> +		    goto next;
> +		offset = logical - found_logical;
> +
> +		raid_stripe = btrfs_item_ptr(leaf, slot, struct btrfs_dp_stripe);
> +		for (i = 0; i < num_stripes; i++) {
> +			if (btrfs_stripe_extent_devid_nr(leaf, raid_stripe, i) != devid)
> +				continue;
> +			*physical = btrfs_stripe_extent_offset_nr(leaf, raid_stripe, i) + offset;
> +			goto out;
> +		}
> +next:
> +		ret = btrfs_next_item(stripe_root, path);
> +		if (ret)

This will leak 1 if we don't find a stripe, probably should do EUCLEAN if we
don't have a raid stripe for this?  Thanks,

Josef
diff mbox series

Patch

diff --git a/fs/btrfs/raid-stripe-tree.c b/fs/btrfs/raid-stripe-tree.c
index 370ea68fe343..ecc8205be760 100644
--- a/fs/btrfs/raid-stripe-tree.c
+++ b/fs/btrfs/raid-stripe-tree.c
@@ -1,10 +1,78 @@ 
 // SPDX-License-Identifier: GPL-2.0
 
+#include <linux/btrfs_tree.h>
+
 #include "ctree.h"
 #include "transaction.h"
 #include "disk-io.h"
 #include "raid-stripe-tree.h"
 #include "volumes.h"
+#include "misc.h"
+
+int btrfs_get_raid_extent_offset(struct btrfs_fs_info *fs_info,
+				 u64 logical, u64 length, u64 map_type,
+				 u64 devid, u64 *physical)
+{
+	struct btrfs_root *stripe_root = fs_info->stripe_root;
+	struct btrfs_dp_stripe *raid_stripe;
+	struct btrfs_key stripe_key;
+	struct btrfs_key found_key;
+	struct btrfs_path *path;
+	struct extent_buffer *leaf;
+	u64 offset;
+	u64 found_logical, found_length;
+	int num_stripes;
+	int slot;
+	int ret;
+	int i;
+
+	stripe_key.objectid = logical;
+	stripe_key.type = BTRFS_RAID_STRIPE_KEY;
+	stripe_key.offset = length;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	num_stripes = btrfs_bg_type_to_factor(map_type);
+
+	ret = btrfs_search_slot_for_read(stripe_root, &stripe_key, path, 0, 0);
+	if (ret < 0) {
+		goto out;
+	}
+
+	if (ret == 1)
+		ret = 0;
+
+	while (1) {
+		leaf = path->nodes[0];
+		slot = path->slots[0];
+
+		btrfs_item_key_to_cpu(leaf, &found_key, slot);
+		found_logical = found_key.objectid;
+		found_length = found_key.offset;
+
+		if (!in_range(logical, found_logical, found_length))
+		    goto next;
+		offset = logical - found_logical;
+
+		raid_stripe = btrfs_item_ptr(leaf, slot, struct btrfs_dp_stripe);
+		for (i = 0; i < num_stripes; i++) {
+			if (btrfs_stripe_extent_devid_nr(leaf, raid_stripe, i) != devid)
+				continue;
+			*physical = btrfs_stripe_extent_offset_nr(leaf, raid_stripe, i) + offset;
+			goto out;
+		}
+next:
+		ret = btrfs_next_item(stripe_root, path);
+		if (ret)
+			break;
+	}
+out:
+	btrfs_free_path(path);
+
+	return ret;
+}
 
 int btrfs_delete_raid_extent(struct btrfs_trans_handle *trans, u64 start,
 			     u64 length)
diff --git a/fs/btrfs/raid-stripe-tree.h b/fs/btrfs/raid-stripe-tree.h
index 766634df8601..1bfa6274eef8 100644
--- a/fs/btrfs/raid-stripe-tree.h
+++ b/fs/btrfs/raid-stripe-tree.h
@@ -5,6 +5,9 @@ 
 
 #include "volumes.h"
 
+int btrfs_get_raid_extent_offset(struct btrfs_fs_info *fs_info,
+				 u64 logical, u64 length, u64 map_type,
+				 u64 devid, u64 *physical);
 int btrfs_delete_raid_extent(struct btrfs_trans_handle *trans, u64 start,
 			     u64 length);
 void btrfs_raid_stripe_tree_fn(struct work_struct *work);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 36acef2ae5d8..38329728425c 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6559,11 +6559,29 @@  static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
 		ret = -ENOMEM;
 		goto out;
 	}
+	bioc->map_type = map->type;
 
 	for (i = 0; i < num_stripes; i++) {
-		bioc->stripes[i].physical = map->stripes[stripe_index].physical +
-			stripe_offset + stripe_nr * map->stripe_len;
+		u64 physical;
+
 		bioc->stripes[i].dev = map->stripes[stripe_index].dev;
+
+		if (fs_info->stripe_root && op == BTRFS_MAP_READ &&
+		   btrfs_need_stripe_tree_update(bioc)) {
+			ret = btrfs_get_raid_extent_offset(fs_info, logical,
+							   map->stripe_len,
+							   map->type,
+							   bioc->stripes[i].dev->devid,
+							   &physical);
+			if (ret) {
+				btrfs_put_bioc(bioc);
+				goto out;
+			}
+		} else {
+			physical = map->stripes[stripe_index].physical +
+				stripe_offset + stripe_nr * map->stripe_len;
+		}
+		bioc->stripes[i].physical = physical;
 		stripe_index++;
 	}
 
@@ -6600,7 +6618,6 @@  static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
 	}
 
 	*bioc_ret = bioc;
-	bioc->map_type = map->type;
 	bioc->num_stripes = num_stripes;
 	bioc->max_errors = max_errors;
 	bioc->mirror_num = mirror_num;