Introduce a new function, btrfs_get_chunk_stripe_len() to get correct
stripe length.
This is very handy for lowmem mode, which checks the mapping between
device extent and chunk item.
Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com>
---
volumes.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
volumes.h | 3 +++
2 files changed, 47 insertions(+)
diff --git a/volumes.c b/volumes.c
index 57534314..1c291edb 100644
--- a/volumes.c
+++ b/volumes.c
@@ -2285,3 +2285,47 @@ out:
return ret;
}
+
+/*
+ * Get stripe length from chunk item and its stripe items
+ *
+ * Caller should only call this function after validating the chunk item
+ * by using btrfs_check_chunk_valid().
+ */
+u64 btrfs_stripe_length(struct btrfs_fs_info *fs_info,
+ struct extent_buffer *leaf,
+ struct btrfs_chunk *chunk)
+{
+ u64 stripe_len;
+ u64 chunk_len;
+ u32 num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
+ u64 profile = btrfs_chunk_type(leaf, chunk) &
+ BTRFS_BLOCK_GROUP_PROFILE_MASK;
+
+ chunk_len = btrfs_chunk_length(leaf, chunk);
+
+ switch (profile) {
+ case 0: /* Single profile */
+ case BTRFS_BLOCK_GROUP_RAID1:
+ case BTRFS_BLOCK_GROUP_DUP:
+ stripe_len = chunk_len;
+ break;
+ case BTRFS_BLOCK_GROUP_RAID0:
+ stripe_len = chunk_len / num_stripes;
+ break;
+ case BTRFS_BLOCK_GROUP_RAID5:
+ stripe_len = chunk_len / (num_stripes - 1);
+ break;
+ case BTRFS_BLOCK_GROUP_RAID6:
+ stripe_len = chunk_len / (num_stripes - 2);
+ break;
+ case BTRFS_BLOCK_GROUP_RAID10:
+ stripe_len = chunk_len / (num_stripes /
+ btrfs_chunk_sub_stripes(leaf, chunk));
+ break;
+ default:
+ /* Invalid chunk profile found */
+ BUG_ON(1);
+ }
+ return stripe_len;
+}
diff --git a/volumes.h b/volumes.h
index 699b0bae..fc0a775b 100644
--- a/volumes.h
+++ b/volumes.h
@@ -246,4 +246,7 @@ int btrfs_check_chunk_valid(struct btrfs_root *root,
struct extent_buffer *leaf,
struct btrfs_chunk *chunk,
int slot, u64 logical);
+u64 btrfs_stripe_length(struct btrfs_fs_info *fs_info,
+ struct extent_buffer *leaf,
+ struct btrfs_chunk *chunk);
#endif
--
2.13.0
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