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btrfs: Remove V0 extent support

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The v0 compat code was introduced in commit 5d4f98a28c
("Btrfs: Mixed back reference  (FORWARD ROLLING FORMAT CHANGE)") 9
years ago, which was merged in 2.6.31. This means that the code is
there to support filesystems which are _VERY_ old and if you are using
btrfs on such an old kernel, you have much bigger problems. This coupled
with the fact that no one is likely testing/maintining this code likely
means it has bugs lurking. All things considered I think 43 kernel
releases later it's high time this remnant of the past got removed.

This patch removes all code wrapped in #ifdefs but leaves the BUG_ONs in case
we have a v0 with no support intact as a sort of safety-net.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Nikolay Borisov
2018-06-21 09:45:00 +03:00
committed by David Sterba
parent 4de426cd39
commit a79865c680
5 changed files with 4 additions and 394 deletions
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30
fs/btrfs/print-tree.c
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@@ -52,18 +52,8 @@ static void print_extent_item(struct extent_buffer *eb, int slot, int type)
u64 offset;
int ref_index = 0;
if (item_size < sizeof(*ei)) {
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
struct btrfs_extent_item_v0 *ei0;
BUG_ON(item_size != sizeof(*ei0));
ei0 = btrfs_item_ptr(eb, slot, struct btrfs_extent_item_v0);
pr_info("\t\textent refs %u\n",
btrfs_extent_refs_v0(eb, ei0));
return;
#else
if (item_size < sizeof(*ei))
BUG();
#endif
}
ei = btrfs_item_ptr(eb, slot, struct btrfs_extent_item);
flags = btrfs_extent_flags(eb, ei);
@@ -133,20 +123,6 @@ static void print_extent_item(struct extent_buffer *eb, int slot, int type)
WARN_ON(ptr > end);
}
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
static void print_extent_ref_v0(struct extent_buffer *eb, int slot)
{
struct btrfs_extent_ref_v0 *ref0;
ref0 = btrfs_item_ptr(eb, slot, struct btrfs_extent_ref_v0);
printk("\t\textent back ref root %llu gen %llu owner %llu num_refs %lu\n",
btrfs_ref_root_v0(eb, ref0),
btrfs_ref_generation_v0(eb, ref0),
btrfs_ref_objectid_v0(eb, ref0),
(unsigned long)btrfs_ref_count_v0(eb, ref0));
}
#endif
static void print_uuid_item(struct extent_buffer *l, unsigned long offset,
u32 item_size)
{
@@ -280,11 +256,7 @@ void btrfs_print_leaf(struct extent_buffer *l)
btrfs_file_extent_ram_bytes(l, fi));
break;
case BTRFS_EXTENT_REF_V0_KEY:
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
print_extent_ref_v0(l, i);
#else
BUG();
#endif
break;
case BTRFS_BLOCK_GROUP_ITEM_KEY:
bi = btrfs_item_ptr(l, i,