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btrfs: Remove V0 extent support
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The v0 compat code was introduced in commit 5d4f98a
("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>
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Nikolay Borisov authored and David Sterba committed Aug 6, 2018
1 parent 4de426c commit a79865c
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Showing 5 changed files with 4 additions and 394 deletions.
6 changes: 1 addition & 5 deletions fs/btrfs/ctree.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -888,11 +888,7 @@ int btrfs_block_can_be_shared(struct btrfs_root *root,
btrfs_root_last_snapshot(&root->root_item) ||
btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)))
return 1;
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
return 1;
#endif

return 0;
}

Expand Down
2 changes: 0 additions & 2 deletions fs/btrfs/ctree.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -55,8 +55,6 @@ struct btrfs_ordered_sum;

#define BTRFS_OLDEST_GENERATION 0ULL

#define BTRFS_COMPAT_EXTENT_TREE_V0

/*
* the max metadata block size. This limit is somewhat artificial,
* but the memmove costs go through the roof for larger blocks.
Expand Down
209 changes: 1 addition & 208 deletions fs/btrfs/extent-tree.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -867,17 +867,7 @@ int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
num_refs = btrfs_extent_refs(leaf, ei);
extent_flags = btrfs_extent_flags(leaf, ei);
} else {
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
struct btrfs_extent_item_v0 *ei0;
BUG_ON(item_size != sizeof(*ei0));
ei0 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_item_v0);
num_refs = btrfs_extent_refs_v0(leaf, ei0);
/* FIXME: this isn't correct for data */
extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
#else
BUG();
#endif
}
BUG_ON(num_refs == 0);
} else {
Expand Down Expand Up @@ -1036,89 +1026,6 @@ int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
* tree block info structure.
*/

#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
struct btrfs_path *path,
u64 owner, u32 extra_size)
{
struct btrfs_root *root = fs_info->extent_root;
struct btrfs_extent_item *item;
struct btrfs_extent_item_v0 *ei0;
struct btrfs_extent_ref_v0 *ref0;
struct btrfs_tree_block_info *bi;
struct extent_buffer *leaf;
struct btrfs_key key;
struct btrfs_key found_key;
u32 new_size = sizeof(*item);
u64 refs;
int ret;

leaf = path->nodes[0];
BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));

btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
ei0 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_item_v0);
refs = btrfs_extent_refs_v0(leaf, ei0);

if (owner == (u64)-1) {
while (1) {
if (path->slots[0] >= btrfs_header_nritems(leaf)) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
return ret;
BUG_ON(ret > 0); /* Corruption */
leaf = path->nodes[0];
}
btrfs_item_key_to_cpu(leaf, &found_key,
path->slots[0]);
BUG_ON(key.objectid != found_key.objectid);
if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
path->slots[0]++;
continue;
}
ref0 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_ref_v0);
owner = btrfs_ref_objectid_v0(leaf, ref0);
break;
}
}
btrfs_release_path(path);

if (owner < BTRFS_FIRST_FREE_OBJECTID)
new_size += sizeof(*bi);

new_size -= sizeof(*ei0);
ret = btrfs_search_slot(trans, root, &key, path,
new_size + extra_size, 1);
if (ret < 0)
return ret;
BUG_ON(ret); /* Corruption */

btrfs_extend_item(fs_info, path, new_size);

leaf = path->nodes[0];
item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
btrfs_set_extent_refs(leaf, item, refs);
/* FIXME: get real generation */
btrfs_set_extent_generation(leaf, item, 0);
if (owner < BTRFS_FIRST_FREE_OBJECTID) {
btrfs_set_extent_flags(leaf, item,
BTRFS_EXTENT_FLAG_TREE_BLOCK |
BTRFS_BLOCK_FLAG_FULL_BACKREF);
bi = (struct btrfs_tree_block_info *)(item + 1);
/* FIXME: get first key of the block */
memzero_extent_buffer(leaf, (unsigned long)bi, sizeof(*bi));
btrfs_set_tree_block_level(leaf, bi, (int)owner);
} else {
btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
}
btrfs_mark_buffer_dirty(leaf);
return 0;
}
#endif

/*
* is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required,
* is_data == BTRFS_REF_TYPE_DATA, data type is requried,
Expand Down Expand Up @@ -1247,17 +1154,6 @@ static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
if (parent) {
if (!ret)
return 0;
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
key.type = BTRFS_EXTENT_REF_V0_KEY;
btrfs_release_path(path);
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret < 0) {
err = ret;
goto fail;
}
if (!ret)
return 0;
#endif
goto fail;
}

Expand Down Expand Up @@ -1400,13 +1296,6 @@ static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
ref2 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_shared_data_ref);
num_refs = btrfs_shared_data_ref_count(leaf, ref2);
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
} else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
struct btrfs_extent_ref_v0 *ref0;
ref0 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_ref_v0);
num_refs = btrfs_ref_count_v0(leaf, ref0);
#endif
} else {
BUG();
}
Expand All @@ -1422,14 +1311,6 @@ static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
else {
struct btrfs_extent_ref_v0 *ref0;
ref0 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_ref_v0);
btrfs_set_ref_count_v0(leaf, ref0, num_refs);
}
#endif
btrfs_mark_buffer_dirty(leaf);
}
return ret;
Expand Down Expand Up @@ -1469,13 +1350,6 @@ static noinline u32 extent_data_ref_count(struct btrfs_path *path,
ref2 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_shared_data_ref);
num_refs = btrfs_shared_data_ref_count(leaf, ref2);
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
} else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
struct btrfs_extent_ref_v0 *ref0;
ref0 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_ref_v0);
num_refs = btrfs_ref_count_v0(leaf, ref0);
#endif
} else {
WARN_ON(1);
}
Expand Down Expand Up @@ -1503,15 +1377,6 @@ static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0)
ret = -ENOENT;
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
if (ret == -ENOENT && parent) {
btrfs_release_path(path);
key.type = BTRFS_EXTENT_REF_V0_KEY;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0)
ret = -ENOENT;
}
#endif
return ret;
}

Expand Down Expand Up @@ -1676,22 +1541,6 @@ int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,

leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
if (item_size < sizeof(*ei)) {
if (!insert) {
err = -ENOENT;
goto out;
}
ret = convert_extent_item_v0(trans, fs_info, path, owner,
extra_size);
if (ret < 0) {
err = ret;
goto out;
}
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
}
#endif
BUG_ON(item_size < sizeof(*ei));

ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
Expand Down Expand Up @@ -2416,17 +2265,6 @@ static int run_delayed_extent_op(struct btrfs_trans_handle *trans,

leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
if (item_size < sizeof(*ei)) {
ret = convert_extent_item_v0(trans, fs_info, path, (u64)-1, 0);
if (ret < 0) {
err = ret;
goto out;
}
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
}
#endif
BUG_ON(item_size < sizeof(*ei));
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
__run_delayed_extent_op(extent_op, leaf, ei);
Expand Down Expand Up @@ -3238,12 +3076,6 @@ static noinline int check_committed_ref(struct btrfs_root *root,

ret = 1;
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
if (item_size < sizeof(*ei)) {
WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
goto out;
}
#endif
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);

if (item_size != sizeof(*ei) +
Expand Down Expand Up @@ -6888,11 +6720,7 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
break;
extent_slot--;
}
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
if (found_extent && item_size < sizeof(*ei))
found_extent = 0;
#endif

if (!found_extent) {
BUG_ON(iref);
ret = remove_extent_backref(trans, path, NULL,
Expand Down Expand Up @@ -6968,41 +6796,6 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans,

leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, extent_slot);
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
if (item_size < sizeof(*ei)) {
BUG_ON(found_extent || extent_slot != path->slots[0]);
ret = convert_extent_item_v0(trans, info, path, owner_objectid,
0);
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
goto out;
}

btrfs_release_path(path);
path->leave_spinning = 1;

key.objectid = bytenr;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = num_bytes;

ret = btrfs_search_slot(trans, extent_root, &key, path,
-1, 1);
if (ret) {
btrfs_err(info,
"umm, got %d back from search, was looking for %llu",
ret, bytenr);
btrfs_print_leaf(path->nodes[0]);
}
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
goto out;
}

extent_slot = path->slots[0];
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, extent_slot);
}
#endif
BUG_ON(item_size < sizeof(*ei));
ei = btrfs_item_ptr(leaf, extent_slot,
struct btrfs_extent_item);
Expand Down
30 changes: 1 addition & 29 deletions fs/btrfs/print-tree.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down Expand Up @@ -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)
{
Expand Down Expand Up @@ -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,
Expand Down
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