diff options
Diffstat (limited to 'fs/btrfs/ref-verify.c')
| -rw-r--r-- | fs/btrfs/ref-verify.c | 1031 |
1 files changed, 1031 insertions, 0 deletions
diff --git a/fs/btrfs/ref-verify.c b/fs/btrfs/ref-verify.c new file mode 100644 index 000000000000..34878699d363 --- /dev/null +++ b/fs/btrfs/ref-verify.c @@ -0,0 +1,1031 @@ +/* + * Copyright (C) 2014 Facebook. All rights reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License v2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public + * License along with this program; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 021110-1307, USA. + */ + +#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) { + block_bytenr = btrfs_node_blockptr(path->nodes[level], + path->slots[level]); + gen = btrfs_node_ptr_generation(path->nodes[level], + path->slots[level]); + eb = read_tree_block(fs_info, block_bytenr, gen); + 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_root *root, 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 btrfs_root *root; + 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(root, 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; +} |