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authorNikolay Borisov2019-11-19 14:05:53 +0200
committerDavid Sterba2020-01-23 17:24:35 +0100
commit1776ad172e1ff09d4aa57daac74c56b4e1b0c636 (patch)
tree4c8dcce97a318dc47ed420bd9c491a19fc48c817 /fs/btrfs
parentbf2e2eb060fa29dd892fa42dd0a03f130815acf0 (diff)
btrfs: Refactor btrfs_rmap_block to improve readability
Move variables to appropriate scope. Remove last BUG_ON in the function and rework error handling accordingly. Make the duplicate detection code more straightforward. Use in_range macro. And give variables more descriptive name by explicitly distinguishing between IO stripe size (size recorded in the chunk item) and data stripe size (the size of an actual stripe, constituting a logical chunk/block group). Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/block-group.c55
1 files changed, 33 insertions, 22 deletions
diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 00cb40210b53..14851584e245 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1582,34 +1582,43 @@ int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
struct map_lookup *map;
u64 *buf;
u64 bytenr;
- u64 length;
- u64 stripe_nr;
- u64 rmap_len;
- int i, j, nr = 0;
+ u64 data_stripe_length;
+ u64 io_stripe_size;
+ int i, nr = 0;
+ int ret = 0;
em = btrfs_get_chunk_map(fs_info, chunk_start, 1);
if (IS_ERR(em))
return -EIO;
map = em->map_lookup;
- length = em->len;
- rmap_len = map->stripe_len;
+ data_stripe_length = em->len;
+ io_stripe_size = map->stripe_len;
if (map->type & BTRFS_BLOCK_GROUP_RAID10)
- length = div_u64(length, map->num_stripes / map->sub_stripes);
+ data_stripe_length = div_u64(data_stripe_length,
+ map->num_stripes / map->sub_stripes);
else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
- length = div_u64(length, map->num_stripes);
+ data_stripe_length = div_u64(data_stripe_length, map->num_stripes);
else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
- length = div_u64(length, nr_data_stripes(map));
- rmap_len = map->stripe_len * nr_data_stripes(map);
+ data_stripe_length = div_u64(data_stripe_length,
+ nr_data_stripes(map));
+ io_stripe_size = map->stripe_len * nr_data_stripes(map);
}
buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
- BUG_ON(!buf); /* -ENOMEM */
+ if (!buf) {
+ ret = -ENOMEM;
+ goto out;
+ }
for (i = 0; i < map->num_stripes; i++) {
- if (map->stripes[i].physical > physical ||
- map->stripes[i].physical + length <= physical)
+ bool already_inserted = false;
+ u64 stripe_nr;
+ int j;
+
+ if (!in_range(physical, map->stripes[i].physical,
+ data_stripe_length))
continue;
stripe_nr = physical - map->stripes[i].physical;
@@ -1627,24 +1636,26 @@ int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
* instead of map->stripe_len
*/
- bytenr = chunk_start + stripe_nr * rmap_len;
- WARN_ON(nr >= map->num_stripes);
+ bytenr = chunk_start + stripe_nr * io_stripe_size;
+
+ /* Ensure we don't add duplicate addresses */
for (j = 0; j < nr; j++) {
- if (buf[j] == bytenr)
+ if (buf[j] == bytenr) {
+ already_inserted = true;
break;
+ }
}
- if (j == nr) {
- WARN_ON(nr >= map->num_stripes);
+
+ if (!already_inserted)
buf[nr++] = bytenr;
- }
}
*logical = buf;
*naddrs = nr;
- *stripe_len = rmap_len;
-
+ *stripe_len = io_stripe_size;
+out:
free_extent_map(em);
- return 0;
+ return ret;
}
static int exclude_super_stripes(struct btrfs_block_group *cache)