btrfs: move functions for tree compare to send.c
Send is the only user of tree_compare, we can move it there along with the other helpers and definitions. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba
parent
4b231ae474
commit
18d0f5c6e1
362
fs/btrfs/ctree.c
362
fs/btrfs/ctree.c
|
|
@ -5246,368 +5246,6 @@ out:
|
||||||
return ret;
|
return ret;
|
||||||
}
|
}
|
||||||
|
|
||||||
static int tree_move_down(struct btrfs_path *path, int *level)
|
|
||||||
{
|
|
||||||
struct extent_buffer *eb;
|
|
||||||
|
|
||||||
BUG_ON(*level == 0);
|
|
||||||
eb = btrfs_read_node_slot(path->nodes[*level], path->slots[*level]);
|
|
||||||
if (IS_ERR(eb))
|
|
||||||
return PTR_ERR(eb);
|
|
||||||
|
|
||||||
path->nodes[*level - 1] = eb;
|
|
||||||
path->slots[*level - 1] = 0;
|
|
||||||
(*level)--;
|
|
||||||
return 0;
|
|
||||||
}
|
|
||||||
|
|
||||||
static int tree_move_next_or_upnext(struct btrfs_path *path,
|
|
||||||
int *level, int root_level)
|
|
||||||
{
|
|
||||||
int ret = 0;
|
|
||||||
int nritems;
|
|
||||||
nritems = btrfs_header_nritems(path->nodes[*level]);
|
|
||||||
|
|
||||||
path->slots[*level]++;
|
|
||||||
|
|
||||||
while (path->slots[*level] >= nritems) {
|
|
||||||
if (*level == root_level)
|
|
||||||
return -1;
|
|
||||||
|
|
||||||
/* move upnext */
|
|
||||||
path->slots[*level] = 0;
|
|
||||||
free_extent_buffer(path->nodes[*level]);
|
|
||||||
path->nodes[*level] = NULL;
|
|
||||||
(*level)++;
|
|
||||||
path->slots[*level]++;
|
|
||||||
|
|
||||||
nritems = btrfs_header_nritems(path->nodes[*level]);
|
|
||||||
ret = 1;
|
|
||||||
}
|
|
||||||
return ret;
|
|
||||||
}
|
|
||||||
|
|
||||||
/*
|
|
||||||
* Returns 1 if it had to move up and next. 0 is returned if it moved only next
|
|
||||||
* or down.
|
|
||||||
*/
|
|
||||||
static int tree_advance(struct btrfs_path *path,
|
|
||||||
int *level, int root_level,
|
|
||||||
int allow_down,
|
|
||||||
struct btrfs_key *key)
|
|
||||||
{
|
|
||||||
int ret;
|
|
||||||
|
|
||||||
if (*level == 0 || !allow_down) {
|
|
||||||
ret = tree_move_next_or_upnext(path, level, root_level);
|
|
||||||
} else {
|
|
||||||
ret = tree_move_down(path, level);
|
|
||||||
}
|
|
||||||
if (ret >= 0) {
|
|
||||||
if (*level == 0)
|
|
||||||
btrfs_item_key_to_cpu(path->nodes[*level], key,
|
|
||||||
path->slots[*level]);
|
|
||||||
else
|
|
||||||
btrfs_node_key_to_cpu(path->nodes[*level], key,
|
|
||||||
path->slots[*level]);
|
|
||||||
}
|
|
||||||
return ret;
|
|
||||||
}
|
|
||||||
|
|
||||||
static int tree_compare_item(struct btrfs_path *left_path,
|
|
||||||
struct btrfs_path *right_path,
|
|
||||||
char *tmp_buf)
|
|
||||||
{
|
|
||||||
int cmp;
|
|
||||||
int len1, len2;
|
|
||||||
unsigned long off1, off2;
|
|
||||||
|
|
||||||
len1 = btrfs_item_size_nr(left_path->nodes[0], left_path->slots[0]);
|
|
||||||
len2 = btrfs_item_size_nr(right_path->nodes[0], right_path->slots[0]);
|
|
||||||
if (len1 != len2)
|
|
||||||
return 1;
|
|
||||||
|
|
||||||
off1 = btrfs_item_ptr_offset(left_path->nodes[0], left_path->slots[0]);
|
|
||||||
off2 = btrfs_item_ptr_offset(right_path->nodes[0],
|
|
||||||
right_path->slots[0]);
|
|
||||||
|
|
||||||
read_extent_buffer(left_path->nodes[0], tmp_buf, off1, len1);
|
|
||||||
|
|
||||||
cmp = memcmp_extent_buffer(right_path->nodes[0], tmp_buf, off2, len1);
|
|
||||||
if (cmp)
|
|
||||||
return 1;
|
|
||||||
return 0;
|
|
||||||
}
|
|
||||||
|
|
||||||
#define ADVANCE 1
|
|
||||||
#define ADVANCE_ONLY_NEXT -1
|
|
||||||
|
|
||||||
/*
|
|
||||||
* This function compares two trees and calls the provided callback for
|
|
||||||
* every changed/new/deleted item it finds.
|
|
||||||
* If shared tree blocks are encountered, whole subtrees are skipped, making
|
|
||||||
* the compare pretty fast on snapshotted subvolumes.
|
|
||||||
*
|
|
||||||
* This currently works on commit roots only. As commit roots are read only,
|
|
||||||
* we don't do any locking. The commit roots are protected with transactions.
|
|
||||||
* Transactions are ended and rejoined when a commit is tried in between.
|
|
||||||
*
|
|
||||||
* This function checks for modifications done to the trees while comparing.
|
|
||||||
* If it detects a change, it aborts immediately.
|
|
||||||
*/
|
|
||||||
int btrfs_compare_trees(struct btrfs_root *left_root,
|
|
||||||
struct btrfs_root *right_root,
|
|
||||||
btrfs_changed_cb_t changed_cb, void *ctx)
|
|
||||||
{
|
|
||||||
struct btrfs_fs_info *fs_info = left_root->fs_info;
|
|
||||||
int ret;
|
|
||||||
int cmp;
|
|
||||||
struct btrfs_path *left_path = NULL;
|
|
||||||
struct btrfs_path *right_path = NULL;
|
|
||||||
struct btrfs_key left_key;
|
|
||||||
struct btrfs_key right_key;
|
|
||||||
char *tmp_buf = NULL;
|
|
||||||
int left_root_level;
|
|
||||||
int right_root_level;
|
|
||||||
int left_level;
|
|
||||||
int right_level;
|
|
||||||
int left_end_reached;
|
|
||||||
int right_end_reached;
|
|
||||||
int advance_left;
|
|
||||||
int advance_right;
|
|
||||||
u64 left_blockptr;
|
|
||||||
u64 right_blockptr;
|
|
||||||
u64 left_gen;
|
|
||||||
u64 right_gen;
|
|
||||||
|
|
||||||
left_path = btrfs_alloc_path();
|
|
||||||
if (!left_path) {
|
|
||||||
ret = -ENOMEM;
|
|
||||||
goto out;
|
|
||||||
}
|
|
||||||
right_path = btrfs_alloc_path();
|
|
||||||
if (!right_path) {
|
|
||||||
ret = -ENOMEM;
|
|
||||||
goto out;
|
|
||||||
}
|
|
||||||
|
|
||||||
tmp_buf = kvmalloc(fs_info->nodesize, GFP_KERNEL);
|
|
||||||
if (!tmp_buf) {
|
|
||||||
ret = -ENOMEM;
|
|
||||||
goto out;
|
|
||||||
}
|
|
||||||
|
|
||||||
left_path->search_commit_root = 1;
|
|
||||||
left_path->skip_locking = 1;
|
|
||||||
right_path->search_commit_root = 1;
|
|
||||||
right_path->skip_locking = 1;
|
|
||||||
|
|
||||||
/*
|
|
||||||
* Strategy: Go to the first items of both trees. Then do
|
|
||||||
*
|
|
||||||
* If both trees are at level 0
|
|
||||||
* Compare keys of current items
|
|
||||||
* If left < right treat left item as new, advance left tree
|
|
||||||
* and repeat
|
|
||||||
* If left > right treat right item as deleted, advance right tree
|
|
||||||
* and repeat
|
|
||||||
* If left == right do deep compare of items, treat as changed if
|
|
||||||
* needed, advance both trees and repeat
|
|
||||||
* If both trees are at the same level but not at level 0
|
|
||||||
* Compare keys of current nodes/leafs
|
|
||||||
* If left < right advance left tree and repeat
|
|
||||||
* If left > right advance right tree and repeat
|
|
||||||
* If left == right compare blockptrs of the next nodes/leafs
|
|
||||||
* If they match advance both trees but stay at the same level
|
|
||||||
* and repeat
|
|
||||||
* If they don't match advance both trees while allowing to go
|
|
||||||
* deeper and repeat
|
|
||||||
* If tree levels are different
|
|
||||||
* Advance the tree that needs it and repeat
|
|
||||||
*
|
|
||||||
* Advancing a tree means:
|
|
||||||
* If we are at level 0, try to go to the next slot. If that's not
|
|
||||||
* possible, go one level up and repeat. Stop when we found a level
|
|
||||||
* where we could go to the next slot. We may at this point be on a
|
|
||||||
* node or a leaf.
|
|
||||||
*
|
|
||||||
* If we are not at level 0 and not on shared tree blocks, go one
|
|
||||||
* level deeper.
|
|
||||||
*
|
|
||||||
* If we are not at level 0 and on shared tree blocks, go one slot to
|
|
||||||
* the right if possible or go up and right.
|
|
||||||
*/
|
|
||||||
|
|
||||||
down_read(&fs_info->commit_root_sem);
|
|
||||||
left_level = btrfs_header_level(left_root->commit_root);
|
|
||||||
left_root_level = left_level;
|
|
||||||
left_path->nodes[left_level] =
|
|
||||||
btrfs_clone_extent_buffer(left_root->commit_root);
|
|
||||||
if (!left_path->nodes[left_level]) {
|
|
||||||
up_read(&fs_info->commit_root_sem);
|
|
||||||
ret = -ENOMEM;
|
|
||||||
goto out;
|
|
||||||
}
|
|
||||||
|
|
||||||
right_level = btrfs_header_level(right_root->commit_root);
|
|
||||||
right_root_level = right_level;
|
|
||||||
right_path->nodes[right_level] =
|
|
||||||
btrfs_clone_extent_buffer(right_root->commit_root);
|
|
||||||
if (!right_path->nodes[right_level]) {
|
|
||||||
up_read(&fs_info->commit_root_sem);
|
|
||||||
ret = -ENOMEM;
|
|
||||||
goto out;
|
|
||||||
}
|
|
||||||
up_read(&fs_info->commit_root_sem);
|
|
||||||
|
|
||||||
if (left_level == 0)
|
|
||||||
btrfs_item_key_to_cpu(left_path->nodes[left_level],
|
|
||||||
&left_key, left_path->slots[left_level]);
|
|
||||||
else
|
|
||||||
btrfs_node_key_to_cpu(left_path->nodes[left_level],
|
|
||||||
&left_key, left_path->slots[left_level]);
|
|
||||||
if (right_level == 0)
|
|
||||||
btrfs_item_key_to_cpu(right_path->nodes[right_level],
|
|
||||||
&right_key, right_path->slots[right_level]);
|
|
||||||
else
|
|
||||||
btrfs_node_key_to_cpu(right_path->nodes[right_level],
|
|
||||||
&right_key, right_path->slots[right_level]);
|
|
||||||
|
|
||||||
left_end_reached = right_end_reached = 0;
|
|
||||||
advance_left = advance_right = 0;
|
|
||||||
|
|
||||||
while (1) {
|
|
||||||
if (advance_left && !left_end_reached) {
|
|
||||||
ret = tree_advance(left_path, &left_level,
|
|
||||||
left_root_level,
|
|
||||||
advance_left != ADVANCE_ONLY_NEXT,
|
|
||||||
&left_key);
|
|
||||||
if (ret == -1)
|
|
||||||
left_end_reached = ADVANCE;
|
|
||||||
else if (ret < 0)
|
|
||||||
goto out;
|
|
||||||
advance_left = 0;
|
|
||||||
}
|
|
||||||
if (advance_right && !right_end_reached) {
|
|
||||||
ret = tree_advance(right_path, &right_level,
|
|
||||||
right_root_level,
|
|
||||||
advance_right != ADVANCE_ONLY_NEXT,
|
|
||||||
&right_key);
|
|
||||||
if (ret == -1)
|
|
||||||
right_end_reached = ADVANCE;
|
|
||||||
else if (ret < 0)
|
|
||||||
goto out;
|
|
||||||
advance_right = 0;
|
|
||||||
}
|
|
||||||
|
|
||||||
if (left_end_reached && right_end_reached) {
|
|
||||||
ret = 0;
|
|
||||||
goto out;
|
|
||||||
} else if (left_end_reached) {
|
|
||||||
if (right_level == 0) {
|
|
||||||
ret = changed_cb(left_path, right_path,
|
|
||||||
&right_key,
|
|
||||||
BTRFS_COMPARE_TREE_DELETED,
|
|
||||||
ctx);
|
|
||||||
if (ret < 0)
|
|
||||||
goto out;
|
|
||||||
}
|
|
||||||
advance_right = ADVANCE;
|
|
||||||
continue;
|
|
||||||
} else if (right_end_reached) {
|
|
||||||
if (left_level == 0) {
|
|
||||||
ret = changed_cb(left_path, right_path,
|
|
||||||
&left_key,
|
|
||||||
BTRFS_COMPARE_TREE_NEW,
|
|
||||||
ctx);
|
|
||||||
if (ret < 0)
|
|
||||||
goto out;
|
|
||||||
}
|
|
||||||
advance_left = ADVANCE;
|
|
||||||
continue;
|
|
||||||
}
|
|
||||||
|
|
||||||
if (left_level == 0 && right_level == 0) {
|
|
||||||
cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
|
|
||||||
if (cmp < 0) {
|
|
||||||
ret = changed_cb(left_path, right_path,
|
|
||||||
&left_key,
|
|
||||||
BTRFS_COMPARE_TREE_NEW,
|
|
||||||
ctx);
|
|
||||||
if (ret < 0)
|
|
||||||
goto out;
|
|
||||||
advance_left = ADVANCE;
|
|
||||||
} else if (cmp > 0) {
|
|
||||||
ret = changed_cb(left_path, right_path,
|
|
||||||
&right_key,
|
|
||||||
BTRFS_COMPARE_TREE_DELETED,
|
|
||||||
ctx);
|
|
||||||
if (ret < 0)
|
|
||||||
goto out;
|
|
||||||
advance_right = ADVANCE;
|
|
||||||
} else {
|
|
||||||
enum btrfs_compare_tree_result result;
|
|
||||||
|
|
||||||
WARN_ON(!extent_buffer_uptodate(left_path->nodes[0]));
|
|
||||||
ret = tree_compare_item(left_path, right_path,
|
|
||||||
tmp_buf);
|
|
||||||
if (ret)
|
|
||||||
result = BTRFS_COMPARE_TREE_CHANGED;
|
|
||||||
else
|
|
||||||
result = BTRFS_COMPARE_TREE_SAME;
|
|
||||||
ret = changed_cb(left_path, right_path,
|
|
||||||
&left_key, result, ctx);
|
|
||||||
if (ret < 0)
|
|
||||||
goto out;
|
|
||||||
advance_left = ADVANCE;
|
|
||||||
advance_right = ADVANCE;
|
|
||||||
}
|
|
||||||
} else if (left_level == right_level) {
|
|
||||||
cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
|
|
||||||
if (cmp < 0) {
|
|
||||||
advance_left = ADVANCE;
|
|
||||||
} else if (cmp > 0) {
|
|
||||||
advance_right = ADVANCE;
|
|
||||||
} else {
|
|
||||||
left_blockptr = btrfs_node_blockptr(
|
|
||||||
left_path->nodes[left_level],
|
|
||||||
left_path->slots[left_level]);
|
|
||||||
right_blockptr = btrfs_node_blockptr(
|
|
||||||
right_path->nodes[right_level],
|
|
||||||
right_path->slots[right_level]);
|
|
||||||
left_gen = btrfs_node_ptr_generation(
|
|
||||||
left_path->nodes[left_level],
|
|
||||||
left_path->slots[left_level]);
|
|
||||||
right_gen = btrfs_node_ptr_generation(
|
|
||||||
right_path->nodes[right_level],
|
|
||||||
right_path->slots[right_level]);
|
|
||||||
if (left_blockptr == right_blockptr &&
|
|
||||||
left_gen == right_gen) {
|
|
||||||
/*
|
|
||||||
* As we're on a shared block, don't
|
|
||||||
* allow to go deeper.
|
|
||||||
*/
|
|
||||||
advance_left = ADVANCE_ONLY_NEXT;
|
|
||||||
advance_right = ADVANCE_ONLY_NEXT;
|
|
||||||
} else {
|
|
||||||
advance_left = ADVANCE;
|
|
||||||
advance_right = ADVANCE;
|
|
||||||
}
|
|
||||||
}
|
|
||||||
} else if (left_level < right_level) {
|
|
||||||
advance_right = ADVANCE;
|
|
||||||
} else {
|
|
||||||
advance_left = ADVANCE;
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
out:
|
|
||||||
btrfs_free_path(left_path);
|
|
||||||
btrfs_free_path(right_path);
|
|
||||||
kvfree(tmp_buf);
|
|
||||||
return ret;
|
|
||||||
}
|
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* this is similar to btrfs_next_leaf, but does not try to preserve
|
* this is similar to btrfs_next_leaf, but does not try to preserve
|
||||||
* and fixup the path. It looks for and returns the next key in the
|
* and fixup the path. It looks for and returns the next key in the
|
||||||
|
|
|
||||||
|
|
@ -2590,20 +2590,6 @@ int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
|
||||||
struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent,
|
struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent,
|
||||||
int slot);
|
int slot);
|
||||||
|
|
||||||
enum btrfs_compare_tree_result {
|
|
||||||
BTRFS_COMPARE_TREE_NEW,
|
|
||||||
BTRFS_COMPARE_TREE_DELETED,
|
|
||||||
BTRFS_COMPARE_TREE_CHANGED,
|
|
||||||
BTRFS_COMPARE_TREE_SAME,
|
|
||||||
};
|
|
||||||
typedef int (*btrfs_changed_cb_t)(struct btrfs_path *left_path,
|
|
||||||
struct btrfs_path *right_path,
|
|
||||||
struct btrfs_key *key,
|
|
||||||
enum btrfs_compare_tree_result result,
|
|
||||||
void *ctx);
|
|
||||||
int btrfs_compare_trees(struct btrfs_root *left_root,
|
|
||||||
struct btrfs_root *right_root,
|
|
||||||
btrfs_changed_cb_t cb, void *ctx);
|
|
||||||
int btrfs_cow_block(struct btrfs_trans_handle *trans,
|
int btrfs_cow_block(struct btrfs_trans_handle *trans,
|
||||||
struct btrfs_root *root, struct extent_buffer *buf,
|
struct btrfs_root *root, struct extent_buffer *buf,
|
||||||
struct extent_buffer *parent, int parent_slot,
|
struct extent_buffer *parent, int parent_slot,
|
||||||
|
|
|
||||||
374
fs/btrfs/send.c
374
fs/btrfs/send.c
|
|
@ -260,6 +260,21 @@ struct name_cache_entry {
|
||||||
char name[];
|
char name[];
|
||||||
};
|
};
|
||||||
|
|
||||||
|
#define ADVANCE 1
|
||||||
|
#define ADVANCE_ONLY_NEXT -1
|
||||||
|
|
||||||
|
enum btrfs_compare_tree_result {
|
||||||
|
BTRFS_COMPARE_TREE_NEW,
|
||||||
|
BTRFS_COMPARE_TREE_DELETED,
|
||||||
|
BTRFS_COMPARE_TREE_CHANGED,
|
||||||
|
BTRFS_COMPARE_TREE_SAME,
|
||||||
|
};
|
||||||
|
typedef int (*btrfs_changed_cb_t)(struct btrfs_path *left_path,
|
||||||
|
struct btrfs_path *right_path,
|
||||||
|
struct btrfs_key *key,
|
||||||
|
enum btrfs_compare_tree_result result,
|
||||||
|
void *ctx);
|
||||||
|
|
||||||
__cold
|
__cold
|
||||||
static void inconsistent_snapshot_error(struct send_ctx *sctx,
|
static void inconsistent_snapshot_error(struct send_ctx *sctx,
|
||||||
enum btrfs_compare_tree_result result,
|
enum btrfs_compare_tree_result result,
|
||||||
|
|
@ -6514,6 +6529,365 @@ out:
|
||||||
return ret;
|
return ret;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
static int tree_move_down(struct btrfs_path *path, int *level)
|
||||||
|
{
|
||||||
|
struct extent_buffer *eb;
|
||||||
|
|
||||||
|
BUG_ON(*level == 0);
|
||||||
|
eb = btrfs_read_node_slot(path->nodes[*level], path->slots[*level]);
|
||||||
|
if (IS_ERR(eb))
|
||||||
|
return PTR_ERR(eb);
|
||||||
|
|
||||||
|
path->nodes[*level - 1] = eb;
|
||||||
|
path->slots[*level - 1] = 0;
|
||||||
|
(*level)--;
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int tree_move_next_or_upnext(struct btrfs_path *path,
|
||||||
|
int *level, int root_level)
|
||||||
|
{
|
||||||
|
int ret = 0;
|
||||||
|
int nritems;
|
||||||
|
nritems = btrfs_header_nritems(path->nodes[*level]);
|
||||||
|
|
||||||
|
path->slots[*level]++;
|
||||||
|
|
||||||
|
while (path->slots[*level] >= nritems) {
|
||||||
|
if (*level == root_level)
|
||||||
|
return -1;
|
||||||
|
|
||||||
|
/* move upnext */
|
||||||
|
path->slots[*level] = 0;
|
||||||
|
free_extent_buffer(path->nodes[*level]);
|
||||||
|
path->nodes[*level] = NULL;
|
||||||
|
(*level)++;
|
||||||
|
path->slots[*level]++;
|
||||||
|
|
||||||
|
nritems = btrfs_header_nritems(path->nodes[*level]);
|
||||||
|
ret = 1;
|
||||||
|
}
|
||||||
|
return ret;
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Returns 1 if it had to move up and next. 0 is returned if it moved only next
|
||||||
|
* or down.
|
||||||
|
*/
|
||||||
|
static int tree_advance(struct btrfs_path *path,
|
||||||
|
int *level, int root_level,
|
||||||
|
int allow_down,
|
||||||
|
struct btrfs_key *key)
|
||||||
|
{
|
||||||
|
int ret;
|
||||||
|
|
||||||
|
if (*level == 0 || !allow_down) {
|
||||||
|
ret = tree_move_next_or_upnext(path, level, root_level);
|
||||||
|
} else {
|
||||||
|
ret = tree_move_down(path, level);
|
||||||
|
}
|
||||||
|
if (ret >= 0) {
|
||||||
|
if (*level == 0)
|
||||||
|
btrfs_item_key_to_cpu(path->nodes[*level], key,
|
||||||
|
path->slots[*level]);
|
||||||
|
else
|
||||||
|
btrfs_node_key_to_cpu(path->nodes[*level], key,
|
||||||
|
path->slots[*level]);
|
||||||
|
}
|
||||||
|
return ret;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int tree_compare_item(struct btrfs_path *left_path,
|
||||||
|
struct btrfs_path *right_path,
|
||||||
|
char *tmp_buf)
|
||||||
|
{
|
||||||
|
int cmp;
|
||||||
|
int len1, len2;
|
||||||
|
unsigned long off1, off2;
|
||||||
|
|
||||||
|
len1 = btrfs_item_size_nr(left_path->nodes[0], left_path->slots[0]);
|
||||||
|
len2 = btrfs_item_size_nr(right_path->nodes[0], right_path->slots[0]);
|
||||||
|
if (len1 != len2)
|
||||||
|
return 1;
|
||||||
|
|
||||||
|
off1 = btrfs_item_ptr_offset(left_path->nodes[0], left_path->slots[0]);
|
||||||
|
off2 = btrfs_item_ptr_offset(right_path->nodes[0],
|
||||||
|
right_path->slots[0]);
|
||||||
|
|
||||||
|
read_extent_buffer(left_path->nodes[0], tmp_buf, off1, len1);
|
||||||
|
|
||||||
|
cmp = memcmp_extent_buffer(right_path->nodes[0], tmp_buf, off2, len1);
|
||||||
|
if (cmp)
|
||||||
|
return 1;
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* This function compares two trees and calls the provided callback for
|
||||||
|
* every changed/new/deleted item it finds.
|
||||||
|
* If shared tree blocks are encountered, whole subtrees are skipped, making
|
||||||
|
* the compare pretty fast on snapshotted subvolumes.
|
||||||
|
*
|
||||||
|
* This currently works on commit roots only. As commit roots are read only,
|
||||||
|
* we don't do any locking. The commit roots are protected with transactions.
|
||||||
|
* Transactions are ended and rejoined when a commit is tried in between.
|
||||||
|
*
|
||||||
|
* This function checks for modifications done to the trees while comparing.
|
||||||
|
* If it detects a change, it aborts immediately.
|
||||||
|
*/
|
||||||
|
static int btrfs_compare_trees(struct btrfs_root *left_root,
|
||||||
|
struct btrfs_root *right_root,
|
||||||
|
btrfs_changed_cb_t changed_cb, void *ctx)
|
||||||
|
{
|
||||||
|
struct btrfs_fs_info *fs_info = left_root->fs_info;
|
||||||
|
int ret;
|
||||||
|
int cmp;
|
||||||
|
struct btrfs_path *left_path = NULL;
|
||||||
|
struct btrfs_path *right_path = NULL;
|
||||||
|
struct btrfs_key left_key;
|
||||||
|
struct btrfs_key right_key;
|
||||||
|
char *tmp_buf = NULL;
|
||||||
|
int left_root_level;
|
||||||
|
int right_root_level;
|
||||||
|
int left_level;
|
||||||
|
int right_level;
|
||||||
|
int left_end_reached;
|
||||||
|
int right_end_reached;
|
||||||
|
int advance_left;
|
||||||
|
int advance_right;
|
||||||
|
u64 left_blockptr;
|
||||||
|
u64 right_blockptr;
|
||||||
|
u64 left_gen;
|
||||||
|
u64 right_gen;
|
||||||
|
|
||||||
|
left_path = btrfs_alloc_path();
|
||||||
|
if (!left_path) {
|
||||||
|
ret = -ENOMEM;
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
|
right_path = btrfs_alloc_path();
|
||||||
|
if (!right_path) {
|
||||||
|
ret = -ENOMEM;
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
|
|
||||||
|
tmp_buf = kvmalloc(fs_info->nodesize, GFP_KERNEL);
|
||||||
|
if (!tmp_buf) {
|
||||||
|
ret = -ENOMEM;
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
|
|
||||||
|
left_path->search_commit_root = 1;
|
||||||
|
left_path->skip_locking = 1;
|
||||||
|
right_path->search_commit_root = 1;
|
||||||
|
right_path->skip_locking = 1;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Strategy: Go to the first items of both trees. Then do
|
||||||
|
*
|
||||||
|
* If both trees are at level 0
|
||||||
|
* Compare keys of current items
|
||||||
|
* If left < right treat left item as new, advance left tree
|
||||||
|
* and repeat
|
||||||
|
* If left > right treat right item as deleted, advance right tree
|
||||||
|
* and repeat
|
||||||
|
* If left == right do deep compare of items, treat as changed if
|
||||||
|
* needed, advance both trees and repeat
|
||||||
|
* If both trees are at the same level but not at level 0
|
||||||
|
* Compare keys of current nodes/leafs
|
||||||
|
* If left < right advance left tree and repeat
|
||||||
|
* If left > right advance right tree and repeat
|
||||||
|
* If left == right compare blockptrs of the next nodes/leafs
|
||||||
|
* If they match advance both trees but stay at the same level
|
||||||
|
* and repeat
|
||||||
|
* If they don't match advance both trees while allowing to go
|
||||||
|
* deeper and repeat
|
||||||
|
* If tree levels are different
|
||||||
|
* Advance the tree that needs it and repeat
|
||||||
|
*
|
||||||
|
* Advancing a tree means:
|
||||||
|
* If we are at level 0, try to go to the next slot. If that's not
|
||||||
|
* possible, go one level up and repeat. Stop when we found a level
|
||||||
|
* where we could go to the next slot. We may at this point be on a
|
||||||
|
* node or a leaf.
|
||||||
|
*
|
||||||
|
* If we are not at level 0 and not on shared tree blocks, go one
|
||||||
|
* level deeper.
|
||||||
|
*
|
||||||
|
* If we are not at level 0 and on shared tree blocks, go one slot to
|
||||||
|
* the right if possible or go up and right.
|
||||||
|
*/
|
||||||
|
|
||||||
|
down_read(&fs_info->commit_root_sem);
|
||||||
|
left_level = btrfs_header_level(left_root->commit_root);
|
||||||
|
left_root_level = left_level;
|
||||||
|
left_path->nodes[left_level] =
|
||||||
|
btrfs_clone_extent_buffer(left_root->commit_root);
|
||||||
|
if (!left_path->nodes[left_level]) {
|
||||||
|
up_read(&fs_info->commit_root_sem);
|
||||||
|
ret = -ENOMEM;
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
|
|
||||||
|
right_level = btrfs_header_level(right_root->commit_root);
|
||||||
|
right_root_level = right_level;
|
||||||
|
right_path->nodes[right_level] =
|
||||||
|
btrfs_clone_extent_buffer(right_root->commit_root);
|
||||||
|
if (!right_path->nodes[right_level]) {
|
||||||
|
up_read(&fs_info->commit_root_sem);
|
||||||
|
ret = -ENOMEM;
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
|
up_read(&fs_info->commit_root_sem);
|
||||||
|
|
||||||
|
if (left_level == 0)
|
||||||
|
btrfs_item_key_to_cpu(left_path->nodes[left_level],
|
||||||
|
&left_key, left_path->slots[left_level]);
|
||||||
|
else
|
||||||
|
btrfs_node_key_to_cpu(left_path->nodes[left_level],
|
||||||
|
&left_key, left_path->slots[left_level]);
|
||||||
|
if (right_level == 0)
|
||||||
|
btrfs_item_key_to_cpu(right_path->nodes[right_level],
|
||||||
|
&right_key, right_path->slots[right_level]);
|
||||||
|
else
|
||||||
|
btrfs_node_key_to_cpu(right_path->nodes[right_level],
|
||||||
|
&right_key, right_path->slots[right_level]);
|
||||||
|
|
||||||
|
left_end_reached = right_end_reached = 0;
|
||||||
|
advance_left = advance_right = 0;
|
||||||
|
|
||||||
|
while (1) {
|
||||||
|
if (advance_left && !left_end_reached) {
|
||||||
|
ret = tree_advance(left_path, &left_level,
|
||||||
|
left_root_level,
|
||||||
|
advance_left != ADVANCE_ONLY_NEXT,
|
||||||
|
&left_key);
|
||||||
|
if (ret == -1)
|
||||||
|
left_end_reached = ADVANCE;
|
||||||
|
else if (ret < 0)
|
||||||
|
goto out;
|
||||||
|
advance_left = 0;
|
||||||
|
}
|
||||||
|
if (advance_right && !right_end_reached) {
|
||||||
|
ret = tree_advance(right_path, &right_level,
|
||||||
|
right_root_level,
|
||||||
|
advance_right != ADVANCE_ONLY_NEXT,
|
||||||
|
&right_key);
|
||||||
|
if (ret == -1)
|
||||||
|
right_end_reached = ADVANCE;
|
||||||
|
else if (ret < 0)
|
||||||
|
goto out;
|
||||||
|
advance_right = 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
if (left_end_reached && right_end_reached) {
|
||||||
|
ret = 0;
|
||||||
|
goto out;
|
||||||
|
} else if (left_end_reached) {
|
||||||
|
if (right_level == 0) {
|
||||||
|
ret = changed_cb(left_path, right_path,
|
||||||
|
&right_key,
|
||||||
|
BTRFS_COMPARE_TREE_DELETED,
|
||||||
|
ctx);
|
||||||
|
if (ret < 0)
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
|
advance_right = ADVANCE;
|
||||||
|
continue;
|
||||||
|
} else if (right_end_reached) {
|
||||||
|
if (left_level == 0) {
|
||||||
|
ret = changed_cb(left_path, right_path,
|
||||||
|
&left_key,
|
||||||
|
BTRFS_COMPARE_TREE_NEW,
|
||||||
|
ctx);
|
||||||
|
if (ret < 0)
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
|
advance_left = ADVANCE;
|
||||||
|
continue;
|
||||||
|
}
|
||||||
|
|
||||||
|
if (left_level == 0 && right_level == 0) {
|
||||||
|
cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
|
||||||
|
if (cmp < 0) {
|
||||||
|
ret = changed_cb(left_path, right_path,
|
||||||
|
&left_key,
|
||||||
|
BTRFS_COMPARE_TREE_NEW,
|
||||||
|
ctx);
|
||||||
|
if (ret < 0)
|
||||||
|
goto out;
|
||||||
|
advance_left = ADVANCE;
|
||||||
|
} else if (cmp > 0) {
|
||||||
|
ret = changed_cb(left_path, right_path,
|
||||||
|
&right_key,
|
||||||
|
BTRFS_COMPARE_TREE_DELETED,
|
||||||
|
ctx);
|
||||||
|
if (ret < 0)
|
||||||
|
goto out;
|
||||||
|
advance_right = ADVANCE;
|
||||||
|
} else {
|
||||||
|
enum btrfs_compare_tree_result result;
|
||||||
|
|
||||||
|
WARN_ON(!extent_buffer_uptodate(left_path->nodes[0]));
|
||||||
|
ret = tree_compare_item(left_path, right_path,
|
||||||
|
tmp_buf);
|
||||||
|
if (ret)
|
||||||
|
result = BTRFS_COMPARE_TREE_CHANGED;
|
||||||
|
else
|
||||||
|
result = BTRFS_COMPARE_TREE_SAME;
|
||||||
|
ret = changed_cb(left_path, right_path,
|
||||||
|
&left_key, result, ctx);
|
||||||
|
if (ret < 0)
|
||||||
|
goto out;
|
||||||
|
advance_left = ADVANCE;
|
||||||
|
advance_right = ADVANCE;
|
||||||
|
}
|
||||||
|
} else if (left_level == right_level) {
|
||||||
|
cmp = btrfs_comp_cpu_keys(&left_key, &right_key);
|
||||||
|
if (cmp < 0) {
|
||||||
|
advance_left = ADVANCE;
|
||||||
|
} else if (cmp > 0) {
|
||||||
|
advance_right = ADVANCE;
|
||||||
|
} else {
|
||||||
|
left_blockptr = btrfs_node_blockptr(
|
||||||
|
left_path->nodes[left_level],
|
||||||
|
left_path->slots[left_level]);
|
||||||
|
right_blockptr = btrfs_node_blockptr(
|
||||||
|
right_path->nodes[right_level],
|
||||||
|
right_path->slots[right_level]);
|
||||||
|
left_gen = btrfs_node_ptr_generation(
|
||||||
|
left_path->nodes[left_level],
|
||||||
|
left_path->slots[left_level]);
|
||||||
|
right_gen = btrfs_node_ptr_generation(
|
||||||
|
right_path->nodes[right_level],
|
||||||
|
right_path->slots[right_level]);
|
||||||
|
if (left_blockptr == right_blockptr &&
|
||||||
|
left_gen == right_gen) {
|
||||||
|
/*
|
||||||
|
* As we're on a shared block, don't
|
||||||
|
* allow to go deeper.
|
||||||
|
*/
|
||||||
|
advance_left = ADVANCE_ONLY_NEXT;
|
||||||
|
advance_right = ADVANCE_ONLY_NEXT;
|
||||||
|
} else {
|
||||||
|
advance_left = ADVANCE;
|
||||||
|
advance_right = ADVANCE;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
} else if (left_level < right_level) {
|
||||||
|
advance_right = ADVANCE;
|
||||||
|
} else {
|
||||||
|
advance_left = ADVANCE;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
out:
|
||||||
|
btrfs_free_path(left_path);
|
||||||
|
btrfs_free_path(right_path);
|
||||||
|
kvfree(tmp_buf);
|
||||||
|
return ret;
|
||||||
|
}
|
||||||
|
|
||||||
static int send_subvol(struct send_ctx *sctx)
|
static int send_subvol(struct send_ctx *sctx)
|
||||||
{
|
{
|
||||||
int ret;
|
int ret;
|
||||||
|
|
|
||||||
Loading…
Reference in New Issue