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
* and fixup the path. It looks for and returns the next key in the
struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent,
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,
struct btrfs_root *root, struct extent_buffer *buf,
struct extent_buffer *parent, int parent_slot,
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
static void inconsistent_snapshot_error(struct send_ctx *sctx,
enum btrfs_compare_tree_result result,
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)
{
int ret;
projects / platform / kernel / linux-rpi.git / commitdiff