linux/fs/btrfs/ref-verify.c

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// 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 that's 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 occurred 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)
{
btrfs: ref-verify: Simplify stack trace retrieval Replace the indirection through struct stack_trace with an invocation of the storage array based interface. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: David Sterba <dsterba@suse.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: linux-btrfs@vger.kernel.org Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Alexander Potapenko <glider@google.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: linux-mm@kvack.org Cc: David Rientjes <rientjes@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: kasan-dev@googlegroups.com Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Akinobu Mita <akinobu.mita@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: iommu@lists.linux-foundation.org Cc: Robin Murphy <robin.murphy@arm.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: dm-devel@redhat.com Cc: Mike Snitzer <snitzer@redhat.com> Cc: Alasdair Kergon <agk@redhat.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: intel-gfx@lists.freedesktop.org Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: dri-devel@lists.freedesktop.org Cc: David Airlie <airlied@linux.ie> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Miroslav Benes <mbenes@suse.cz> Cc: linux-arch@vger.kernel.org Link: https://lkml.kernel.org/r/20190425094802.338890064@linutronix.de
2019-04-25 09:45:06 +00:00
ra->trace_len = stack_trace_save(ra->trace, MAX_TRACE, 2);
}
static void __print_stack_trace(struct btrfs_fs_info *fs_info,
struct ref_action *ra)
{
if (ra->trace_len == 0) {
btrfs_err(fs_info, " ref-verify: no stacktrace");
return;
}
btrfs: ref-verify: Simplify stack trace retrieval Replace the indirection through struct stack_trace with an invocation of the storage array based interface. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: David Sterba <dsterba@suse.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: linux-btrfs@vger.kernel.org Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Alexander Potapenko <glider@google.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: linux-mm@kvack.org Cc: David Rientjes <rientjes@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: kasan-dev@googlegroups.com Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Akinobu Mita <akinobu.mita@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: iommu@lists.linux-foundation.org Cc: Robin Murphy <robin.murphy@arm.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: dm-devel@redhat.com Cc: Mike Snitzer <snitzer@redhat.com> Cc: Alasdair Kergon <agk@redhat.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: intel-gfx@lists.freedesktop.org Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: dri-devel@lists.freedesktop.org Cc: David Airlie <airlied@linux.ie> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Miroslav Benes <mbenes@suse.cz> Cc: linux-arch@vger.kernel.org Link: https://lkml.kernel.org/r/20190425094802.338890064@linutronix.de
2019-04-25 09:45:06 +00:00
stack_trace_print(ra->trace, ra->trace_len, 2);
}
#else
static inline void __save_stack_trace(struct ref_action *ra)
{
}
static inline void __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;
btrfs: stop doing GFP_KERNEL memory allocations in the ref verify tool In commit 351cbf6e4410e7 ("btrfs: use nofs allocations for running delayed items") we wrapped all btree updates when running delayed items with memalloc_nofs_save() and memalloc_nofs_restore(), due to a lock inversion detected by lockdep involving reclaim and the mutex of delayed nodes. The problem is because the ref verify tool does some memory allocations with GFP_KERNEL, which can trigger reclaim and reclaim can trigger inode eviction, which requires locking the mutex of an inode's delayed node. On the other hand the ref verify tool is called when allocating metadata extents as part of operations that modify a btree, which is a problem when running delayed nodes, where we do btree updates while holding the mutex of a delayed node. This is what caused the lockdep warning. Instead of wrapping every btree update when running delayed nodes, change the ref verify tool to never do GFP_KERNEL allocations, because: 1) We get less repeated code, which at the moment does not even have a comment mentioning why we need to setup the NOFS context, which is a recommended good practice as mentioned at Documentation/core-api/gfp_mask-from-fs-io.rst 2) The ref verify tool is something meant only for debugging and not something that should be enabled on non-debug / non-development kernels; 3) We may have yet more places outside delayed-inode.c where we have similar problem: doing btree updates while holding some lock and then having the GFP_KERNEL memory allocations, from the ref verify tool, trigger reclaim and trying again to acquire the same lock through the reclaim path. Or we could get more such cases in the future, therefore this change prevents getting into similar cases when using the ref verify tool. Curiously most of the memory allocations done by the ref verify tool were already using GFP_NOFS, except a few ones for no apparent reason. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-07-20 15:05:23 +00:00
re = kzalloc(sizeof(struct root_entry), GFP_NOFS);
be = kzalloc(sizeof(struct block_entry), GFP_NOFS);
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);
} else {
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;
btrfs: stop doing GFP_KERNEL memory allocations in the ref verify tool In commit 351cbf6e4410e7 ("btrfs: use nofs allocations for running delayed items") we wrapped all btree updates when running delayed items with memalloc_nofs_save() and memalloc_nofs_restore(), due to a lock inversion detected by lockdep involving reclaim and the mutex of delayed nodes. The problem is because the ref verify tool does some memory allocations with GFP_KERNEL, which can trigger reclaim and reclaim can trigger inode eviction, which requires locking the mutex of an inode's delayed node. On the other hand the ref verify tool is called when allocating metadata extents as part of operations that modify a btree, which is a problem when running delayed nodes, where we do btree updates while holding the mutex of a delayed node. This is what caused the lockdep warning. Instead of wrapping every btree update when running delayed nodes, change the ref verify tool to never do GFP_KERNEL allocations, because: 1) We get less repeated code, which at the moment does not even have a comment mentioning why we need to setup the NOFS context, which is a recommended good practice as mentioned at Documentation/core-api/gfp_mask-from-fs-io.rst 2) The ref verify tool is something meant only for debugging and not something that should be enabled on non-debug / non-development kernels; 3) We may have yet more places outside delayed-inode.c where we have similar problem: doing btree updates while holding some lock and then having the GFP_KERNEL memory allocations, from the ref verify tool, trigger reclaim and trying again to acquire the same lock through the reclaim path. Or we could get more such cases in the future, therefore this change prevents getting into similar cases when using the ref verify tool. Curiously most of the memory allocations done by the ref verify tool were already using GFP_NOFS, except a few ones for no apparent reason. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-07-20 15:05:23 +00:00
ref = kmalloc(sizeof(struct ref_entry), GFP_NOFS);
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;
btrfs: stop doing GFP_KERNEL memory allocations in the ref verify tool In commit 351cbf6e4410e7 ("btrfs: use nofs allocations for running delayed items") we wrapped all btree updates when running delayed items with memalloc_nofs_save() and memalloc_nofs_restore(), due to a lock inversion detected by lockdep involving reclaim and the mutex of delayed nodes. The problem is because the ref verify tool does some memory allocations with GFP_KERNEL, which can trigger reclaim and reclaim can trigger inode eviction, which requires locking the mutex of an inode's delayed node. On the other hand the ref verify tool is called when allocating metadata extents as part of operations that modify a btree, which is a problem when running delayed nodes, where we do btree updates while holding the mutex of a delayed node. This is what caused the lockdep warning. Instead of wrapping every btree update when running delayed nodes, change the ref verify tool to never do GFP_KERNEL allocations, because: 1) We get less repeated code, which at the moment does not even have a comment mentioning why we need to setup the NOFS context, which is a recommended good practice as mentioned at Documentation/core-api/gfp_mask-from-fs-io.rst 2) The ref verify tool is something meant only for debugging and not something that should be enabled on non-debug / non-development kernels; 3) We may have yet more places outside delayed-inode.c where we have similar problem: doing btree updates while holding some lock and then having the GFP_KERNEL memory allocations, from the ref verify tool, trigger reclaim and trying again to acquire the same lock through the reclaim path. Or we could get more such cases in the future, therefore this change prevents getting into similar cases when using the ref verify tool. Curiously most of the memory allocations done by the ref verify tool were already using GFP_NOFS, except a few ones for no apparent reason. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-07-20 15:05:23 +00:00
ref = kzalloc(sizeof(struct ref_entry), GFP_NOFS);
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);
btrfs: stop doing GFP_KERNEL memory allocations in the ref verify tool In commit 351cbf6e4410e7 ("btrfs: use nofs allocations for running delayed items") we wrapped all btree updates when running delayed items with memalloc_nofs_save() and memalloc_nofs_restore(), due to a lock inversion detected by lockdep involving reclaim and the mutex of delayed nodes. The problem is because the ref verify tool does some memory allocations with GFP_KERNEL, which can trigger reclaim and reclaim can trigger inode eviction, which requires locking the mutex of an inode's delayed node. On the other hand the ref verify tool is called when allocating metadata extents as part of operations that modify a btree, which is a problem when running delayed nodes, where we do btree updates while holding the mutex of a delayed node. This is what caused the lockdep warning. Instead of wrapping every btree update when running delayed nodes, change the ref verify tool to never do GFP_KERNEL allocations, because: 1) We get less repeated code, which at the moment does not even have a comment mentioning why we need to setup the NOFS context, which is a recommended good practice as mentioned at Documentation/core-api/gfp_mask-from-fs-io.rst 2) The ref verify tool is something meant only for debugging and not something that should be enabled on non-debug / non-development kernels; 3) We may have yet more places outside delayed-inode.c where we have similar problem: doing btree updates while holding some lock and then having the GFP_KERNEL memory allocations, from the ref verify tool, trigger reclaim and trying again to acquire the same lock through the reclaim path. Or we could get more such cases in the future, therefore this change prevents getting into similar cases when using the ref verify tool. Curiously most of the memory allocations done by the ref verify tool were already using GFP_NOFS, except a few ones for no apparent reason. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-07-20 15:05:23 +00:00
ref = kzalloc(sizeof(struct ref_entry), GFP_NOFS);
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(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,
int *tree_block_level)
{
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, ret = 0;
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;
fallthrough;
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,
int *tree_block_level)
{
struct extent_buffer *eb;
int ret = 0;
while (level >= 0) {
if (level) {
eb = btrfs_read_node_slot(path->nodes[level],
path->slots[level]);
if (IS_ERR(eb))
return PTR_ERR(eb);
btrfs_tree_read_lock(eb);
path->nodes[level-1] = eb;
path->slots[level-1] = 0;
path->locks[level-1] = BTRFS_READ_LOCK;
} else {
ret = process_leaf(root, path, bytenr, num_bytes,
tree_block_level);
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
*
* 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_fs_info *fs_info,
struct btrfs_ref *generic_ref)
{
struct ref_entry *ref = NULL, *exist;
struct ref_action *ra = NULL;
struct block_entry *be = NULL;
struct root_entry *re = NULL;
int action = generic_ref->action;
int ret = 0;
bool metadata;
u64 bytenr = generic_ref->bytenr;
u64 num_bytes = generic_ref->len;
u64 parent = generic_ref->parent;
u64 ref_root = 0;
u64 owner = 0;
u64 offset = 0;
if (!btrfs_test_opt(fs_info, REF_VERIFY))
return 0;
if (generic_ref->type == BTRFS_REF_METADATA) {
if (!parent)
ref_root = generic_ref->tree_ref.owning_root;
owner = generic_ref->tree_ref.level;
} else if (!parent) {
ref_root = generic_ref->data_ref.owning_root;
owner = generic_ref->data_ref.ino;
offset = generic_ref->data_ref.offset;
}
metadata = owner < BTRFS_FIRST_FREE_OBJECTID;
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;
}
ref->parent = parent;
ref->owner = owner;
ref->root_objectid = ref_root;
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 = generic_ref->real_root;
/*
* 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(fs_info, bytenr, num_bytes, ref_root);
if (IS_ERR(be)) {
kfree(ref);
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);
kfree(ref);
kfree(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 = generic_ref->real_root;
re->root_objectid = generic_ref->real_root;
re->num_refs = 0;
}
spin_lock(&fs_info->ref_verify_lock);
be = lookup_block_entry(&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, bytenr, num_bytes);
dump_ref_action(fs_info, ra);
kfree(ref);
kfree(ra);
goto out_unlock;
} else if (be->num_refs == 0) {
btrfs_err(fs_info,
"trying to do action %d for a bytenr that has 0 total references",
action);
dump_block_entry(fs_info, be);
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(ref);
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(ref);
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(ref);
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 think of some other corner case.
*/
btrfs_err(fs_info, "failed to find root %llu for %llu",
generic_ref->real_root, 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(&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_root *extent_root;
struct btrfs_path *path;
struct extent_buffer *eb;
int tree_block_level = 0;
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;
extent_root = btrfs_extent_root(fs_info, 0);
eb = btrfs_read_lock_root_node(extent_root);
level = btrfs_header_level(eb);
path->nodes[level] = eb;
path->slots[level] = 0;
path->locks[level] = BTRFS_READ_LOCK;
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(extent_root, path, level,
&bytenr, &num_bytes, &tree_block_level);
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;
}