btrfs: cleanup, stop casting for extent_map->lookup everywhere

commit 95617d69326ce386c95e33db7aeb832b45ee9f8f upstream.

Overloading extent_map->bdev to struct map_lookup * might have started out
as a means to an end, but it's a pattern that's used all over the place
now. Let's get rid of the casting and just add a union instead.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.16: drop changes in
 btrfs_start_trans_remove_block_group(),
 btrfs_update_commit_device_bytes_used()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 7ee449d0da8a19c6e00426f1171f79c0e0baba51..7542ba457f09cac0210c755407f9129b3261e08d 100644 (file)
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -614,7 +614,7 @@ static void btrfs_dev_replace_update_device_in_mapping_tree(
                em = lookup_extent_mapping(em_tree, start, (u64)-1);
                if (!em)
                        break;
-               map = (struct map_lookup *)em->bdev;
+               map = em->map_lookup;
                for (i = 0; i < map->num_stripes; i++)
                        if (srcdev == map->stripes[i].dev)
                                map->stripes[i].dev = tgtdev;

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 6a98bddd8f33a96e82d0fe856763e53b67e9b064..84fb56d5c018dbfea2a4b1970e4275ada5daa0fb 100644 (file)
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -76,7 +76,7 @@ void free_extent_map(struct extent_map *em)
                WARN_ON(extent_map_in_tree(em));
                WARN_ON(!list_empty(&em->list));
                if (test_bit(EXTENT_FLAG_FS_MAPPING, &em->flags))
-                       kfree(em->bdev);
+                       kfree(em->map_lookup);
                kmem_cache_free(extent_map_cache, em);
        }
 }

diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
index b2991fd8583efe8ed92de32904eb510542bc1f66..eb8b8fae036bc3c67ceea03220cdca503626546f 100644 (file)
--- a/fs/btrfs/extent_map.h
+++ b/fs/btrfs/extent_map.h
@@ -32,7 +32,15 @@ struct extent_map {
        u64 block_len;
        u64 generation;
        unsigned long flags;
-       struct block_device *bdev;
+       union {
+               struct block_device *bdev;
+
+               /*
+                * used for chunk mappings
+                * flags & EXTENT_FLAG_FS_MAPPING must be set
+                */
+               struct map_lookup *map_lookup;
+       };
        atomic_t refs;
        unsigned int compress_type;
        struct list_head list;

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 70edd60db654fc270cc1405b45fd8fe4f5411fc8..e3a687c472ec46e7d27ad71c25c271376b9bc7d8 100644 (file)
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -2637,7 +2637,7 @@ static noinline_for_stack int scrub_chunk(struct scrub_ctx *sctx,
        if (!em)
                return -EINVAL;
 
-       map = (struct map_lookup *)em->bdev;
+       map = em->map_lookup;
        if (em->start != chunk_offset)
                goto out;
 

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index bd2429fc3809dd8a4f51b4c1550a035b17cc57f2..fcb5c5a9f7cdc248893c77a67f685acac9452c97 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1047,7 +1047,7 @@ static int contains_pending_extent(struct btrfs_trans_handle *trans,
                struct map_lookup *map;
                int i;
 
-               map = (struct map_lookup *)em->bdev;
+               map = em->map_lookup;
                for (i = 0; i < map->num_stripes; i++) {
                        if (map->stripes[i].dev != device)
                                continue;
@@ -2533,7 +2533,7 @@ static int btrfs_relocate_chunk(struct btrfs_root *root,
 
        BUG_ON(!em || em->start > chunk_offset ||
               em->start + em->len < chunk_offset);
-       map = (struct map_lookup *)em->bdev;
+       map = em->map_lookup;
 
        for (i = 0; i < map->num_stripes; i++) {
                ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
@@ -4322,7 +4322,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
                goto error;
        }
        set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
-       em->bdev = (struct block_device *)map;
+       em->map_lookup = map;
        em->start = start;
        em->len = num_bytes;
        em->block_start = 0;
@@ -4405,7 +4405,7 @@ int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
                return -EINVAL;
        }
 
-       map = (struct map_lookup *)em->bdev;
+       map = em->map_lookup;
        item_size = btrfs_chunk_item_size(map->num_stripes);
        stripe_size = em->orig_block_len;
 
@@ -4547,7 +4547,7 @@ int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
                return 0;
        }
 
-       map = (struct map_lookup *)em->bdev;
+       map = em->map_lookup;
        for (i = 0; i < map->num_stripes; i++) {
                if (!map->stripes[i].dev->writeable) {
                        readonly = 1;
@@ -4613,7 +4613,7 @@ int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
                return 1;
        }
 
-       map = (struct map_lookup *)em->bdev;
+       map = em->map_lookup;
        if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
                ret = map->num_stripes;
        else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
@@ -4649,7 +4649,7 @@ unsigned long btrfs_full_stripe_len(struct btrfs_root *root,
        BUG_ON(!em);
 
        BUG_ON(em->start > logical || em->start + em->len < logical);
-       map = (struct map_lookup *)em->bdev;
+       map = em->map_lookup;
        if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
                         BTRFS_BLOCK_GROUP_RAID6)) {
                len = map->stripe_len * nr_data_stripes(map);
@@ -4672,7 +4672,7 @@ int btrfs_is_parity_mirror(struct btrfs_mapping_tree *map_tree,
        BUG_ON(!em);
 
        BUG_ON(em->start > logical || em->start + em->len < logical);
-       map = (struct map_lookup *)em->bdev;
+       map = em->map_lookup;
        if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
                         BTRFS_BLOCK_GROUP_RAID6))
                ret = 1;
@@ -4794,7 +4794,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
                return -EINVAL;
        }
 
-       map = (struct map_lookup *)em->bdev;
+       map = em->map_lookup;
        offset = logical - em->start;
 
        stripe_len = map->stripe_len;
@@ -5321,7 +5321,7 @@ int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
                free_extent_map(em);
                return -EIO;
        }
-       map = (struct map_lookup *)em->bdev;
+       map = em->map_lookup;
 
        length = em->len;
        rmap_len = map->stripe_len;
@@ -5846,7 +5846,7 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
        }
 
        set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
-       em->bdev = (struct block_device *)map;
+       em->map_lookup = map;
        em->start = logical;
        em->len = length;
        em->orig_start = 0;