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Message-ID: <3e1ed108-44c5-4616-922e-542524c0657e@suse.com>
Date: Fri, 15 Sep 2023 09:56:35 +0930
From: Qu Wenruo <wqu@...e.com>
To: Johannes Thumshirn <johannes.thumshirn@....com>,
Chris Mason <clm@...com>, Josef Bacik <josef@...icpanda.com>,
David Sterba <dsterba@...e.com>
Cc: Christoph Hellwig <hch@....de>,
Naohiro Aota <naohiro.aota@....com>,
Damien Le Moal <dlemoal@...nel.org>,
linux-btrfs@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v9 01/11] btrfs: add raid stripe tree definitions
On 2023/9/15 09:52, Qu Wenruo wrote:
>
>
> On 2023/9/15 01:36, Johannes Thumshirn wrote:
>> Add definitions for the raid stripe tree. This tree will hold information
>> about the on-disk layout of the stripes in a RAID set.
>>
>> Each stripe extent has a 1:1 relationship with an on-disk extent item and
>> is doing the logical to per-drive physical address translation for the
>> extent item in question.
>>
>> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@....com>
>> ---
>> fs/btrfs/accessors.h | 10 ++++++++++
>> fs/btrfs/locking.c | 1 +
>> include/uapi/linux/btrfs_tree.h | 31 +++++++++++++++++++++++++++++++
>> 3 files changed, 42 insertions(+)
>>
>> diff --git a/fs/btrfs/accessors.h b/fs/btrfs/accessors.h
>> index f958eccff477..977ff160a024 100644
>> --- a/fs/btrfs/accessors.h
>> +++ b/fs/btrfs/accessors.h
>> @@ -306,6 +306,16 @@ BTRFS_SETGET_FUNCS(timespec_nsec, struct
>> btrfs_timespec, nsec, 32);
>> BTRFS_SETGET_STACK_FUNCS(stack_timespec_sec, struct btrfs_timespec,
>> sec, 64);
>> BTRFS_SETGET_STACK_FUNCS(stack_timespec_nsec, struct btrfs_timespec,
>> nsec, 32);
>> +BTRFS_SETGET_FUNCS(stripe_extent_encoding, struct
>> btrfs_stripe_extent, encoding, 8);
>> +BTRFS_SETGET_FUNCS(raid_stride_devid, struct btrfs_raid_stride,
>> devid, 64);
>> +BTRFS_SETGET_FUNCS(raid_stride_physical, struct btrfs_raid_stride,
>> physical, 64);
>> +BTRFS_SETGET_FUNCS(raid_stride_length, struct btrfs_raid_stride,
>> length, 64);
>> +BTRFS_SETGET_STACK_FUNCS(stack_stripe_extent_encoding,
>> + struct btrfs_stripe_extent, encoding, 8);
>> +BTRFS_SETGET_STACK_FUNCS(stack_raid_stride_devid, struct
>> btrfs_raid_stride, devid, 64);
>> +BTRFS_SETGET_STACK_FUNCS(stack_raid_stride_physical, struct
>> btrfs_raid_stride, physical, 64);
>> +BTRFS_SETGET_STACK_FUNCS(stack_raid_stride_length, struct
>> btrfs_raid_stride, length, 64);
>> +
>> /* struct btrfs_dev_extent */
>> BTRFS_SETGET_FUNCS(dev_extent_chunk_tree, struct btrfs_dev_extent,
>> chunk_tree, 64);
>> BTRFS_SETGET_FUNCS(dev_extent_chunk_objectid, struct btrfs_dev_extent,
>> diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
>> index 6ac4fd8cc8dc..74d8e2003f58 100644
>> --- a/fs/btrfs/locking.c
>> +++ b/fs/btrfs/locking.c
>> @@ -74,6 +74,7 @@ static struct btrfs_lockdep_keyset {
>> { .id = BTRFS_UUID_TREE_OBJECTID, DEFINE_NAME("uuid") },
>> { .id = BTRFS_FREE_SPACE_TREE_OBJECTID,
>> DEFINE_NAME("free-space") },
>> { .id = BTRFS_BLOCK_GROUP_TREE_OBJECTID,
>> DEFINE_NAME("block-group") },
>> + { .id = BTRFS_RAID_STRIPE_TREE_OBJECTID,
>> DEFINE_NAME("raid-stripe") },
>> { .id = 0, DEFINE_NAME("tree") },
>> };
>> diff --git a/include/uapi/linux/btrfs_tree.h
>> b/include/uapi/linux/btrfs_tree.h
>> index fc3c32186d7e..6d9c43416b6e 100644
>> --- a/include/uapi/linux/btrfs_tree.h
>> +++ b/include/uapi/linux/btrfs_tree.h
>> @@ -73,6 +73,9 @@
>> /* Holds the block group items for extent tree v2. */
>> #define BTRFS_BLOCK_GROUP_TREE_OBJECTID 11ULL
>> +/* Tracks RAID stripes in block groups. */
>> +#define BTRFS_RAID_STRIPE_TREE_OBJECTID 12ULL
>> +
>> /* device stats in the device tree */
>> #define BTRFS_DEV_STATS_OBJECTID 0ULL
>> @@ -261,6 +264,8 @@
>> #define BTRFS_DEV_ITEM_KEY 216
>> #define BTRFS_CHUNK_ITEM_KEY 228
>> +#define BTRFS_RAID_STRIPE_KEY 230
>> +
>> /*
>> * Records the overall state of the qgroups.
>> * There's only one instance of this key present,
>> @@ -719,6 +724,32 @@ struct btrfs_free_space_header {
>> __le64 num_bitmaps;
>> } __attribute__ ((__packed__));
>> +struct btrfs_raid_stride {
>> + /* The btrfs device-id this raid extent lives on */
>> + __le64 devid;
>> + /* The physical location on disk */
>> + __le64 physical;
>> + /* The length of stride on this disk */
>> + __le64 length;
Forgot to mention, for btrfs_stripe_extent structure, its key is
(PHYSICAL, RAID_STRIPE_KEY, LENGTH) right?
So is the length in the btrfs_raid_stride duplicated and we can save 8
bytes?
Thanks,
Qu
>> +} __attribute__ ((__packed__));
>> +
>> +/* The stripe_extent::encoding, 1:1 mapping of enum btrfs_raid_types */
>> +#define BTRFS_STRIPE_RAID0 1
>> +#define BTRFS_STRIPE_RAID1 2
>> +#define BTRFS_STRIPE_DUP 3
>> +#define BTRFS_STRIPE_RAID10 4
>> +#define BTRFS_STRIPE_RAID5 5
>> +#define BTRFS_STRIPE_RAID6 6
>> +#define BTRFS_STRIPE_RAID1C3 7
>> +#define BTRFS_STRIPE_RAID1C4 8
>> +
>> +struct btrfs_stripe_extent {
>> + __u8 encoding;
>
> Considerng the encoding for now is 1:1 map of btrfs_raid_types, and
> normally we use variable like @raid_index for such usage, have
> considered rename it to "raid_index" or "profile_index" instead?
>
> Another thing is, you may want to add extra tree-checker code to verify
> the btrfs_stripe_extent members.
>
> For encoding, it should be all be the known numbers, and item size for
> alignment.
>
> The same for physical/length alignment checks.
>
> Thanks,
> Qu
>> + __u8 reserved[7];
>> + /* An array of raid strides this stripe is composed of */
>> + struct btrfs_raid_stride strides[];
>> +} __attribute__ ((__packed__));
>> +
>> #define BTRFS_HEADER_FLAG_WRITTEN (1ULL << 0)
>> #define BTRFS_HEADER_FLAG_RELOC (1ULL << 1)
>>
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