v4.19.13 snapshot.
diff --git a/fs/btrfs/ref-verify.c b/fs/btrfs/ref-verify.c
new file mode 100644
index 0000000..e5b9e59
--- /dev/null
+++ b/fs/btrfs/ref-verify.c
@@ -0,0 +1,1021 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2014 Facebook. All rights reserved.
+ */
+
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+#include "ctree.h"
+#include "disk-io.h"
+#include "locking.h"
+#include "delayed-ref.h"
+#include "ref-verify.h"
+
+/*
+ * Used to keep track the roots and number of refs each root has for a given
+ * bytenr. This just tracks the number of direct references, no shared
+ * references.
+ */
+struct root_entry {
+ u64 root_objectid;
+ u64 num_refs;
+ struct rb_node node;
+};
+
+/*
+ * These are meant to represent what should exist in the extent tree, these can
+ * be used to verify the extent tree is consistent as these should all match
+ * what the extent tree says.
+ */
+struct ref_entry {
+ u64 root_objectid;
+ u64 parent;
+ u64 owner;
+ u64 offset;
+ u64 num_refs;
+ struct rb_node node;
+};
+
+#define MAX_TRACE 16
+
+/*
+ * Whenever we add/remove a reference we record the action. The action maps
+ * back to the delayed ref action. We hold the ref we are changing in the
+ * action so we can account for the history properly, and we record the root we
+ * were called with since it could be different from ref_root. We also store
+ * stack traces because thats how I roll.
+ */
+struct ref_action {
+ int action;
+ u64 root;
+ struct ref_entry ref;
+ struct list_head list;
+ unsigned long trace[MAX_TRACE];
+ unsigned int trace_len;
+};
+
+/*
+ * One of these for every block we reference, it holds the roots and references
+ * to it as well as all of the ref actions that have occured to it. We never
+ * free it until we unmount the file system in order to make sure re-allocations
+ * are happening properly.
+ */
+struct block_entry {
+ u64 bytenr;
+ u64 len;
+ u64 num_refs;
+ int metadata;
+ int from_disk;
+ struct rb_root roots;
+ struct rb_root refs;
+ struct rb_node node;
+ struct list_head actions;
+};
+
+static struct block_entry *insert_block_entry(struct rb_root *root,
+ struct block_entry *be)
+{
+ struct rb_node **p = &root->rb_node;
+ struct rb_node *parent_node = NULL;
+ struct block_entry *entry;
+
+ while (*p) {
+ parent_node = *p;
+ entry = rb_entry(parent_node, struct block_entry, node);
+ if (entry->bytenr > be->bytenr)
+ p = &(*p)->rb_left;
+ else if (entry->bytenr < be->bytenr)
+ p = &(*p)->rb_right;
+ else
+ return entry;
+ }
+
+ rb_link_node(&be->node, parent_node, p);
+ rb_insert_color(&be->node, root);
+ return NULL;
+}
+
+static struct block_entry *lookup_block_entry(struct rb_root *root, u64 bytenr)
+{
+ struct rb_node *n;
+ struct block_entry *entry = NULL;
+
+ n = root->rb_node;
+ while (n) {
+ entry = rb_entry(n, struct block_entry, node);
+ if (entry->bytenr < bytenr)
+ n = n->rb_right;
+ else if (entry->bytenr > bytenr)
+ n = n->rb_left;
+ else
+ return entry;
+ }
+ return NULL;
+}
+
+static struct root_entry *insert_root_entry(struct rb_root *root,
+ struct root_entry *re)
+{
+ struct rb_node **p = &root->rb_node;
+ struct rb_node *parent_node = NULL;
+ struct root_entry *entry;
+
+ while (*p) {
+ parent_node = *p;
+ entry = rb_entry(parent_node, struct root_entry, node);
+ if (entry->root_objectid > re->root_objectid)
+ p = &(*p)->rb_left;
+ else if (entry->root_objectid < re->root_objectid)
+ p = &(*p)->rb_right;
+ else
+ return entry;
+ }
+
+ rb_link_node(&re->node, parent_node, p);
+ rb_insert_color(&re->node, root);
+ return NULL;
+
+}
+
+static int comp_refs(struct ref_entry *ref1, struct ref_entry *ref2)
+{
+ if (ref1->root_objectid < ref2->root_objectid)
+ return -1;
+ if (ref1->root_objectid > ref2->root_objectid)
+ return 1;
+ if (ref1->parent < ref2->parent)
+ return -1;
+ if (ref1->parent > ref2->parent)
+ return 1;
+ if (ref1->owner < ref2->owner)
+ return -1;
+ if (ref1->owner > ref2->owner)
+ return 1;
+ if (ref1->offset < ref2->offset)
+ return -1;
+ if (ref1->offset > ref2->offset)
+ return 1;
+ return 0;
+}
+
+static struct ref_entry *insert_ref_entry(struct rb_root *root,
+ struct ref_entry *ref)
+{
+ struct rb_node **p = &root->rb_node;
+ struct rb_node *parent_node = NULL;
+ struct ref_entry *entry;
+ int cmp;
+
+ while (*p) {
+ parent_node = *p;
+ entry = rb_entry(parent_node, struct ref_entry, node);
+ cmp = comp_refs(entry, ref);
+ if (cmp > 0)
+ p = &(*p)->rb_left;
+ else if (cmp < 0)
+ p = &(*p)->rb_right;
+ else
+ return entry;
+ }
+
+ rb_link_node(&ref->node, parent_node, p);
+ rb_insert_color(&ref->node, root);
+ return NULL;
+
+}
+
+static struct root_entry *lookup_root_entry(struct rb_root *root, u64 objectid)
+{
+ struct rb_node *n;
+ struct root_entry *entry = NULL;
+
+ n = root->rb_node;
+ while (n) {
+ entry = rb_entry(n, struct root_entry, node);
+ if (entry->root_objectid < objectid)
+ n = n->rb_right;
+ else if (entry->root_objectid > objectid)
+ n = n->rb_left;
+ else
+ return entry;
+ }
+ return NULL;
+}
+
+#ifdef CONFIG_STACKTRACE
+static void __save_stack_trace(struct ref_action *ra)
+{
+ struct stack_trace stack_trace;
+
+ stack_trace.max_entries = MAX_TRACE;
+ stack_trace.nr_entries = 0;
+ stack_trace.entries = ra->trace;
+ stack_trace.skip = 2;
+ save_stack_trace(&stack_trace);
+ ra->trace_len = stack_trace.nr_entries;
+}
+
+static void __print_stack_trace(struct btrfs_fs_info *fs_info,
+ struct ref_action *ra)
+{
+ struct stack_trace trace;
+
+ if (ra->trace_len == 0) {
+ btrfs_err(fs_info, " ref-verify: no stacktrace");
+ return;
+ }
+ trace.nr_entries = ra->trace_len;
+ trace.entries = ra->trace;
+ print_stack_trace(&trace, 2);
+}
+#else
+static void inline __save_stack_trace(struct ref_action *ra)
+{
+}
+
+static void inline __print_stack_trace(struct btrfs_fs_info *fs_info,
+ struct ref_action *ra)
+{
+ btrfs_err(fs_info, " ref-verify: no stacktrace support");
+}
+#endif
+
+static void free_block_entry(struct block_entry *be)
+{
+ struct root_entry *re;
+ struct ref_entry *ref;
+ struct ref_action *ra;
+ struct rb_node *n;
+
+ while ((n = rb_first(&be->roots))) {
+ re = rb_entry(n, struct root_entry, node);
+ rb_erase(&re->node, &be->roots);
+ kfree(re);
+ }
+
+ while((n = rb_first(&be->refs))) {
+ ref = rb_entry(n, struct ref_entry, node);
+ rb_erase(&ref->node, &be->refs);
+ kfree(ref);
+ }
+
+ while (!list_empty(&be->actions)) {
+ ra = list_first_entry(&be->actions, struct ref_action,
+ list);
+ list_del(&ra->list);
+ kfree(ra);
+ }
+ kfree(be);
+}
+
+static struct block_entry *add_block_entry(struct btrfs_fs_info *fs_info,
+ u64 bytenr, u64 len,
+ u64 root_objectid)
+{
+ struct block_entry *be = NULL, *exist;
+ struct root_entry *re = NULL;
+
+ re = kzalloc(sizeof(struct root_entry), GFP_KERNEL);
+ be = kzalloc(sizeof(struct block_entry), GFP_KERNEL);
+ if (!be || !re) {
+ kfree(re);
+ kfree(be);
+ return ERR_PTR(-ENOMEM);
+ }
+ be->bytenr = bytenr;
+ be->len = len;
+
+ re->root_objectid = root_objectid;
+ re->num_refs = 0;
+
+ spin_lock(&fs_info->ref_verify_lock);
+ exist = insert_block_entry(&fs_info->block_tree, be);
+ if (exist) {
+ if (root_objectid) {
+ struct root_entry *exist_re;
+
+ exist_re = insert_root_entry(&exist->roots, re);
+ if (exist_re)
+ kfree(re);
+ }
+ kfree(be);
+ return exist;
+ }
+
+ be->num_refs = 0;
+ be->metadata = 0;
+ be->from_disk = 0;
+ be->roots = RB_ROOT;
+ be->refs = RB_ROOT;
+ INIT_LIST_HEAD(&be->actions);
+ if (root_objectid)
+ insert_root_entry(&be->roots, re);
+ else
+ kfree(re);
+ return be;
+}
+
+static int add_tree_block(struct btrfs_fs_info *fs_info, u64 ref_root,
+ u64 parent, u64 bytenr, int level)
+{
+ struct block_entry *be;
+ struct root_entry *re;
+ struct ref_entry *ref = NULL, *exist;
+
+ ref = kmalloc(sizeof(struct ref_entry), GFP_KERNEL);
+ if (!ref)
+ return -ENOMEM;
+
+ if (parent)
+ ref->root_objectid = 0;
+ else
+ ref->root_objectid = ref_root;
+ ref->parent = parent;
+ ref->owner = level;
+ ref->offset = 0;
+ ref->num_refs = 1;
+
+ be = add_block_entry(fs_info, bytenr, fs_info->nodesize, ref_root);
+ if (IS_ERR(be)) {
+ kfree(ref);
+ return PTR_ERR(be);
+ }
+ be->num_refs++;
+ be->from_disk = 1;
+ be->metadata = 1;
+
+ if (!parent) {
+ ASSERT(ref_root);
+ re = lookup_root_entry(&be->roots, ref_root);
+ ASSERT(re);
+ re->num_refs++;
+ }
+ exist = insert_ref_entry(&be->refs, ref);
+ if (exist) {
+ exist->num_refs++;
+ kfree(ref);
+ }
+ spin_unlock(&fs_info->ref_verify_lock);
+
+ return 0;
+}
+
+static int add_shared_data_ref(struct btrfs_fs_info *fs_info,
+ u64 parent, u32 num_refs, u64 bytenr,
+ u64 num_bytes)
+{
+ struct block_entry *be;
+ struct ref_entry *ref;
+
+ ref = kzalloc(sizeof(struct ref_entry), GFP_KERNEL);
+ if (!ref)
+ return -ENOMEM;
+ be = add_block_entry(fs_info, bytenr, num_bytes, 0);
+ if (IS_ERR(be)) {
+ kfree(ref);
+ return PTR_ERR(be);
+ }
+ be->num_refs += num_refs;
+
+ ref->parent = parent;
+ ref->num_refs = num_refs;
+ if (insert_ref_entry(&be->refs, ref)) {
+ spin_unlock(&fs_info->ref_verify_lock);
+ btrfs_err(fs_info, "existing shared ref when reading from disk?");
+ kfree(ref);
+ return -EINVAL;
+ }
+ spin_unlock(&fs_info->ref_verify_lock);
+ return 0;
+}
+
+static int add_extent_data_ref(struct btrfs_fs_info *fs_info,
+ struct extent_buffer *leaf,
+ struct btrfs_extent_data_ref *dref,
+ u64 bytenr, u64 num_bytes)
+{
+ struct block_entry *be;
+ struct ref_entry *ref;
+ struct root_entry *re;
+ u64 ref_root = btrfs_extent_data_ref_root(leaf, dref);
+ u64 owner = btrfs_extent_data_ref_objectid(leaf, dref);
+ u64 offset = btrfs_extent_data_ref_offset(leaf, dref);
+ u32 num_refs = btrfs_extent_data_ref_count(leaf, dref);
+
+ ref = kzalloc(sizeof(struct ref_entry), GFP_KERNEL);
+ if (!ref)
+ return -ENOMEM;
+ be = add_block_entry(fs_info, bytenr, num_bytes, ref_root);
+ if (IS_ERR(be)) {
+ kfree(ref);
+ return PTR_ERR(be);
+ }
+ be->num_refs += num_refs;
+
+ ref->parent = 0;
+ ref->owner = owner;
+ ref->root_objectid = ref_root;
+ ref->offset = offset;
+ ref->num_refs = num_refs;
+ if (insert_ref_entry(&be->refs, ref)) {
+ spin_unlock(&fs_info->ref_verify_lock);
+ btrfs_err(fs_info, "existing ref when reading from disk?");
+ kfree(ref);
+ return -EINVAL;
+ }
+
+ re = lookup_root_entry(&be->roots, ref_root);
+ if (!re) {
+ spin_unlock(&fs_info->ref_verify_lock);
+ btrfs_err(fs_info, "missing root in new block entry?");
+ return -EINVAL;
+ }
+ re->num_refs += num_refs;
+ spin_unlock(&fs_info->ref_verify_lock);
+ return 0;
+}
+
+static int process_extent_item(struct btrfs_fs_info *fs_info,
+ struct btrfs_path *path, struct btrfs_key *key,
+ int slot, int *tree_block_level)
+{
+ struct btrfs_extent_item *ei;
+ struct btrfs_extent_inline_ref *iref;
+ struct btrfs_extent_data_ref *dref;
+ struct btrfs_shared_data_ref *sref;
+ struct extent_buffer *leaf = path->nodes[0];
+ u32 item_size = btrfs_item_size_nr(leaf, slot);
+ unsigned long end, ptr;
+ u64 offset, flags, count;
+ int type, ret;
+
+ ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
+ flags = btrfs_extent_flags(leaf, ei);
+
+ if ((key->type == BTRFS_EXTENT_ITEM_KEY) &&
+ flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
+ struct btrfs_tree_block_info *info;
+
+ info = (struct btrfs_tree_block_info *)(ei + 1);
+ *tree_block_level = btrfs_tree_block_level(leaf, info);
+ iref = (struct btrfs_extent_inline_ref *)(info + 1);
+ } else {
+ if (key->type == BTRFS_METADATA_ITEM_KEY)
+ *tree_block_level = key->offset;
+ iref = (struct btrfs_extent_inline_ref *)(ei + 1);
+ }
+
+ ptr = (unsigned long)iref;
+ end = (unsigned long)ei + item_size;
+ while (ptr < end) {
+ iref = (struct btrfs_extent_inline_ref *)ptr;
+ type = btrfs_extent_inline_ref_type(leaf, iref);
+ offset = btrfs_extent_inline_ref_offset(leaf, iref);
+ switch (type) {
+ case BTRFS_TREE_BLOCK_REF_KEY:
+ ret = add_tree_block(fs_info, offset, 0, key->objectid,
+ *tree_block_level);
+ break;
+ case BTRFS_SHARED_BLOCK_REF_KEY:
+ ret = add_tree_block(fs_info, 0, offset, key->objectid,
+ *tree_block_level);
+ break;
+ case BTRFS_EXTENT_DATA_REF_KEY:
+ dref = (struct btrfs_extent_data_ref *)(&iref->offset);
+ ret = add_extent_data_ref(fs_info, leaf, dref,
+ key->objectid, key->offset);
+ break;
+ case BTRFS_SHARED_DATA_REF_KEY:
+ sref = (struct btrfs_shared_data_ref *)(iref + 1);
+ count = btrfs_shared_data_ref_count(leaf, sref);
+ ret = add_shared_data_ref(fs_info, offset, count,
+ key->objectid, key->offset);
+ break;
+ default:
+ btrfs_err(fs_info, "invalid key type in iref");
+ ret = -EINVAL;
+ break;
+ }
+ if (ret)
+ break;
+ ptr += btrfs_extent_inline_ref_size(type);
+ }
+ return ret;
+}
+
+static int process_leaf(struct btrfs_root *root,
+ struct btrfs_path *path, u64 *bytenr, u64 *num_bytes)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct extent_buffer *leaf = path->nodes[0];
+ struct btrfs_extent_data_ref *dref;
+ struct btrfs_shared_data_ref *sref;
+ u32 count;
+ int i = 0, tree_block_level = 0, ret;
+ struct btrfs_key key;
+ int nritems = btrfs_header_nritems(leaf);
+
+ for (i = 0; i < nritems; i++) {
+ btrfs_item_key_to_cpu(leaf, &key, i);
+ switch (key.type) {
+ case BTRFS_EXTENT_ITEM_KEY:
+ *num_bytes = key.offset;
+ case BTRFS_METADATA_ITEM_KEY:
+ *bytenr = key.objectid;
+ ret = process_extent_item(fs_info, path, &key, i,
+ &tree_block_level);
+ break;
+ case BTRFS_TREE_BLOCK_REF_KEY:
+ ret = add_tree_block(fs_info, key.offset, 0,
+ key.objectid, tree_block_level);
+ break;
+ case BTRFS_SHARED_BLOCK_REF_KEY:
+ ret = add_tree_block(fs_info, 0, key.offset,
+ key.objectid, tree_block_level);
+ break;
+ case BTRFS_EXTENT_DATA_REF_KEY:
+ dref = btrfs_item_ptr(leaf, i,
+ struct btrfs_extent_data_ref);
+ ret = add_extent_data_ref(fs_info, leaf, dref, *bytenr,
+ *num_bytes);
+ break;
+ case BTRFS_SHARED_DATA_REF_KEY:
+ sref = btrfs_item_ptr(leaf, i,
+ struct btrfs_shared_data_ref);
+ count = btrfs_shared_data_ref_count(leaf, sref);
+ ret = add_shared_data_ref(fs_info, key.offset, count,
+ *bytenr, *num_bytes);
+ break;
+ default:
+ break;
+ }
+ if (ret)
+ break;
+ }
+ return ret;
+}
+
+/* Walk down to the leaf from the given level */
+static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
+ int level, u64 *bytenr, u64 *num_bytes)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct extent_buffer *eb;
+ u64 block_bytenr, gen;
+ int ret = 0;
+
+ while (level >= 0) {
+ if (level) {
+ struct btrfs_key first_key;
+
+ block_bytenr = btrfs_node_blockptr(path->nodes[level],
+ path->slots[level]);
+ gen = btrfs_node_ptr_generation(path->nodes[level],
+ path->slots[level]);
+ btrfs_node_key_to_cpu(path->nodes[level], &first_key,
+ path->slots[level]);
+ eb = read_tree_block(fs_info, block_bytenr, gen,
+ level - 1, &first_key);
+ if (IS_ERR(eb))
+ return PTR_ERR(eb);
+ if (!extent_buffer_uptodate(eb)) {
+ free_extent_buffer(eb);
+ return -EIO;
+ }
+ btrfs_tree_read_lock(eb);
+ btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
+ path->nodes[level-1] = eb;
+ path->slots[level-1] = 0;
+ path->locks[level-1] = BTRFS_READ_LOCK_BLOCKING;
+ } else {
+ ret = process_leaf(root, path, bytenr, num_bytes);
+ if (ret)
+ break;
+ }
+ level--;
+ }
+ return ret;
+}
+
+/* Walk up to the next node that needs to be processed */
+static int walk_up_tree(struct btrfs_path *path, int *level)
+{
+ int l;
+
+ for (l = 0; l < BTRFS_MAX_LEVEL; l++) {
+ if (!path->nodes[l])
+ continue;
+ if (l) {
+ path->slots[l]++;
+ if (path->slots[l] <
+ btrfs_header_nritems(path->nodes[l])) {
+ *level = l;
+ return 0;
+ }
+ }
+ btrfs_tree_unlock_rw(path->nodes[l], path->locks[l]);
+ free_extent_buffer(path->nodes[l]);
+ path->nodes[l] = NULL;
+ path->slots[l] = 0;
+ path->locks[l] = 0;
+ }
+
+ return 1;
+}
+
+static void dump_ref_action(struct btrfs_fs_info *fs_info,
+ struct ref_action *ra)
+{
+ btrfs_err(fs_info,
+" Ref action %d, root %llu, ref_root %llu, parent %llu, owner %llu, offset %llu, num_refs %llu",
+ ra->action, ra->root, ra->ref.root_objectid, ra->ref.parent,
+ ra->ref.owner, ra->ref.offset, ra->ref.num_refs);
+ __print_stack_trace(fs_info, ra);
+}
+
+/*
+ * Dumps all the information from the block entry to printk, it's going to be
+ * awesome.
+ */
+static void dump_block_entry(struct btrfs_fs_info *fs_info,
+ struct block_entry *be)
+{
+ struct ref_entry *ref;
+ struct root_entry *re;
+ struct ref_action *ra;
+ struct rb_node *n;
+
+ btrfs_err(fs_info,
+"dumping block entry [%llu %llu], num_refs %llu, metadata %d, from disk %d",
+ be->bytenr, be->len, be->num_refs, be->metadata,
+ be->from_disk);
+
+ for (n = rb_first(&be->refs); n; n = rb_next(n)) {
+ ref = rb_entry(n, struct ref_entry, node);
+ btrfs_err(fs_info,
+" ref root %llu, parent %llu, owner %llu, offset %llu, num_refs %llu",
+ ref->root_objectid, ref->parent, ref->owner,
+ ref->offset, ref->num_refs);
+ }
+
+ for (n = rb_first(&be->roots); n; n = rb_next(n)) {
+ re = rb_entry(n, struct root_entry, node);
+ btrfs_err(fs_info, " root entry %llu, num_refs %llu",
+ re->root_objectid, re->num_refs);
+ }
+
+ list_for_each_entry(ra, &be->actions, list)
+ dump_ref_action(fs_info, ra);
+}
+
+/*
+ * btrfs_ref_tree_mod: called when we modify a ref for a bytenr
+ * @root: the root we are making this modification from.
+ * @bytenr: the bytenr we are modifying.
+ * @num_bytes: number of bytes.
+ * @parent: the parent bytenr.
+ * @ref_root: the original root owner of the bytenr.
+ * @owner: level in the case of metadata, inode in the case of data.
+ * @offset: 0 for metadata, file offset for data.
+ * @action: the action that we are doing, this is the same as the delayed ref
+ * action.
+ *
+ * This will add an action item to the given bytenr and do sanity checks to make
+ * sure we haven't messed something up. If we are making a new allocation and
+ * this block entry has history we will delete all previous actions as long as
+ * our sanity checks pass as they are no longer needed.
+ */
+int btrfs_ref_tree_mod(struct btrfs_root *root, u64 bytenr, u64 num_bytes,
+ u64 parent, u64 ref_root, u64 owner, u64 offset,
+ int action)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct ref_entry *ref = NULL, *exist;
+ struct ref_action *ra = NULL;
+ struct block_entry *be = NULL;
+ struct root_entry *re = NULL;
+ int ret = 0;
+ bool metadata = owner < BTRFS_FIRST_FREE_OBJECTID;
+
+ if (!btrfs_test_opt(root->fs_info, REF_VERIFY))
+ return 0;
+
+ ref = kzalloc(sizeof(struct ref_entry), GFP_NOFS);
+ ra = kmalloc(sizeof(struct ref_action), GFP_NOFS);
+ if (!ra || !ref) {
+ kfree(ref);
+ kfree(ra);
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ if (parent) {
+ ref->parent = parent;
+ } else {
+ ref->root_objectid = ref_root;
+ ref->owner = owner;
+ ref->offset = offset;
+ }
+ ref->num_refs = (action == BTRFS_DROP_DELAYED_REF) ? -1 : 1;
+
+ memcpy(&ra->ref, ref, sizeof(struct ref_entry));
+ /*
+ * Save the extra info from the delayed ref in the ref action to make it
+ * easier to figure out what is happening. The real ref's we add to the
+ * ref tree need to reflect what we save on disk so it matches any
+ * on-disk refs we pre-loaded.
+ */
+ ra->ref.owner = owner;
+ ra->ref.offset = offset;
+ ra->ref.root_objectid = ref_root;
+ __save_stack_trace(ra);
+
+ INIT_LIST_HEAD(&ra->list);
+ ra->action = action;
+ ra->root = root->objectid;
+
+ /*
+ * This is an allocation, preallocate the block_entry in case we haven't
+ * used it before.
+ */
+ ret = -EINVAL;
+ if (action == BTRFS_ADD_DELAYED_EXTENT) {
+ /*
+ * For subvol_create we'll just pass in whatever the parent root
+ * is and the new root objectid, so let's not treat the passed
+ * in root as if it really has a ref for this bytenr.
+ */
+ be = add_block_entry(root->fs_info, bytenr, num_bytes, ref_root);
+ if (IS_ERR(be)) {
+ kfree(ra);
+ ret = PTR_ERR(be);
+ goto out;
+ }
+ be->num_refs++;
+ if (metadata)
+ be->metadata = 1;
+
+ if (be->num_refs != 1) {
+ btrfs_err(fs_info,
+ "re-allocated a block that still has references to it!");
+ dump_block_entry(fs_info, be);
+ dump_ref_action(fs_info, ra);
+ goto out_unlock;
+ }
+
+ while (!list_empty(&be->actions)) {
+ struct ref_action *tmp;
+
+ tmp = list_first_entry(&be->actions, struct ref_action,
+ list);
+ list_del(&tmp->list);
+ kfree(tmp);
+ }
+ } else {
+ struct root_entry *tmp;
+
+ if (!parent) {
+ re = kmalloc(sizeof(struct root_entry), GFP_NOFS);
+ if (!re) {
+ kfree(ref);
+ kfree(ra);
+ ret = -ENOMEM;
+ goto out;
+ }
+ /*
+ * This is the root that is modifying us, so it's the
+ * one we want to lookup below when we modify the
+ * re->num_refs.
+ */
+ ref_root = root->objectid;
+ re->root_objectid = root->objectid;
+ re->num_refs = 0;
+ }
+
+ spin_lock(&root->fs_info->ref_verify_lock);
+ be = lookup_block_entry(&root->fs_info->block_tree, bytenr);
+ if (!be) {
+ btrfs_err(fs_info,
+"trying to do action %d to bytenr %llu num_bytes %llu but there is no existing entry!",
+ action, (unsigned long long)bytenr,
+ (unsigned long long)num_bytes);
+ dump_ref_action(fs_info, ra);
+ kfree(ref);
+ kfree(ra);
+ goto out_unlock;
+ }
+
+ if (!parent) {
+ tmp = insert_root_entry(&be->roots, re);
+ if (tmp) {
+ kfree(re);
+ re = tmp;
+ }
+ }
+ }
+
+ exist = insert_ref_entry(&be->refs, ref);
+ if (exist) {
+ if (action == BTRFS_DROP_DELAYED_REF) {
+ if (exist->num_refs == 0) {
+ btrfs_err(fs_info,
+"dropping a ref for a existing root that doesn't have a ref on the block");
+ dump_block_entry(fs_info, be);
+ dump_ref_action(fs_info, ra);
+ kfree(ra);
+ goto out_unlock;
+ }
+ exist->num_refs--;
+ if (exist->num_refs == 0) {
+ rb_erase(&exist->node, &be->refs);
+ kfree(exist);
+ }
+ } else if (!be->metadata) {
+ exist->num_refs++;
+ } else {
+ btrfs_err(fs_info,
+"attempting to add another ref for an existing ref on a tree block");
+ dump_block_entry(fs_info, be);
+ dump_ref_action(fs_info, ra);
+ kfree(ra);
+ goto out_unlock;
+ }
+ kfree(ref);
+ } else {
+ if (action == BTRFS_DROP_DELAYED_REF) {
+ btrfs_err(fs_info,
+"dropping a ref for a root that doesn't have a ref on the block");
+ dump_block_entry(fs_info, be);
+ dump_ref_action(fs_info, ra);
+ kfree(ra);
+ goto out_unlock;
+ }
+ }
+
+ if (!parent && !re) {
+ re = lookup_root_entry(&be->roots, ref_root);
+ if (!re) {
+ /*
+ * This shouldn't happen because we will add our re
+ * above when we lookup the be with !parent, but just in
+ * case catch this case so we don't panic because I
+ * didn't thik of some other corner case.
+ */
+ btrfs_err(fs_info, "failed to find root %llu for %llu",
+ root->objectid, be->bytenr);
+ dump_block_entry(fs_info, be);
+ dump_ref_action(fs_info, ra);
+ kfree(ra);
+ goto out_unlock;
+ }
+ }
+ if (action == BTRFS_DROP_DELAYED_REF) {
+ if (re)
+ re->num_refs--;
+ be->num_refs--;
+ } else if (action == BTRFS_ADD_DELAYED_REF) {
+ be->num_refs++;
+ if (re)
+ re->num_refs++;
+ }
+ list_add_tail(&ra->list, &be->actions);
+ ret = 0;
+out_unlock:
+ spin_unlock(&root->fs_info->ref_verify_lock);
+out:
+ if (ret)
+ btrfs_clear_opt(fs_info->mount_opt, REF_VERIFY);
+ return ret;
+}
+
+/* Free up the ref cache */
+void btrfs_free_ref_cache(struct btrfs_fs_info *fs_info)
+{
+ struct block_entry *be;
+ struct rb_node *n;
+
+ if (!btrfs_test_opt(fs_info, REF_VERIFY))
+ return;
+
+ spin_lock(&fs_info->ref_verify_lock);
+ while ((n = rb_first(&fs_info->block_tree))) {
+ be = rb_entry(n, struct block_entry, node);
+ rb_erase(&be->node, &fs_info->block_tree);
+ free_block_entry(be);
+ cond_resched_lock(&fs_info->ref_verify_lock);
+ }
+ spin_unlock(&fs_info->ref_verify_lock);
+}
+
+void btrfs_free_ref_tree_range(struct btrfs_fs_info *fs_info, u64 start,
+ u64 len)
+{
+ struct block_entry *be = NULL, *entry;
+ struct rb_node *n;
+
+ if (!btrfs_test_opt(fs_info, REF_VERIFY))
+ return;
+
+ spin_lock(&fs_info->ref_verify_lock);
+ n = fs_info->block_tree.rb_node;
+ while (n) {
+ entry = rb_entry(n, struct block_entry, node);
+ if (entry->bytenr < start) {
+ n = n->rb_right;
+ } else if (entry->bytenr > start) {
+ n = n->rb_left;
+ } else {
+ be = entry;
+ break;
+ }
+ /* We want to get as close to start as possible */
+ if (be == NULL ||
+ (entry->bytenr < start && be->bytenr > start) ||
+ (entry->bytenr < start && entry->bytenr > be->bytenr))
+ be = entry;
+ }
+
+ /*
+ * Could have an empty block group, maybe have something to check for
+ * this case to verify we were actually empty?
+ */
+ if (!be) {
+ spin_unlock(&fs_info->ref_verify_lock);
+ return;
+ }
+
+ n = &be->node;
+ while (n) {
+ be = rb_entry(n, struct block_entry, node);
+ n = rb_next(n);
+ if (be->bytenr < start && be->bytenr + be->len > start) {
+ btrfs_err(fs_info,
+ "block entry overlaps a block group [%llu,%llu]!",
+ start, len);
+ dump_block_entry(fs_info, be);
+ continue;
+ }
+ if (be->bytenr < start)
+ continue;
+ if (be->bytenr >= start + len)
+ break;
+ if (be->bytenr + be->len > start + len) {
+ btrfs_err(fs_info,
+ "block entry overlaps a block group [%llu,%llu]!",
+ start, len);
+ dump_block_entry(fs_info, be);
+ }
+ rb_erase(&be->node, &fs_info->block_tree);
+ free_block_entry(be);
+ }
+ spin_unlock(&fs_info->ref_verify_lock);
+}
+
+/* Walk down all roots and build the ref tree, meant to be called at mount */
+int btrfs_build_ref_tree(struct btrfs_fs_info *fs_info)
+{
+ struct btrfs_path *path;
+ struct extent_buffer *eb;
+ u64 bytenr = 0, num_bytes = 0;
+ int ret, level;
+
+ if (!btrfs_test_opt(fs_info, REF_VERIFY))
+ return 0;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ eb = btrfs_read_lock_root_node(fs_info->extent_root);
+ btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
+ level = btrfs_header_level(eb);
+ path->nodes[level] = eb;
+ path->slots[level] = 0;
+ path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
+
+ while (1) {
+ /*
+ * We have to keep track of the bytenr/num_bytes we last hit
+ * because we could have run out of space for an inline ref, and
+ * would have had to added a ref key item which may appear on a
+ * different leaf from the original extent item.
+ */
+ ret = walk_down_tree(fs_info->extent_root, path, level,
+ &bytenr, &num_bytes);
+ if (ret)
+ break;
+ ret = walk_up_tree(path, &level);
+ if (ret < 0)
+ break;
+ if (ret > 0) {
+ ret = 0;
+ break;
+ }
+ }
+ if (ret) {
+ btrfs_clear_opt(fs_info->mount_opt, REF_VERIFY);
+ btrfs_free_ref_cache(fs_info);
+ }
+ btrfs_free_path(path);
+ return ret;
+}