On Fri, Sep 01, 2017 at 03:09:30AM -0400, jo...@toxicpanda.com wrote:
> From: Josef Bacik <jba...@fb.com>
>
> We were having corruption issues that were tied back to problems with the
> extent
> tree. In order to track them down I built this tool to try and find the
> culprit, which was pretty successful. If you compile with this tool on it
> will
> live verify every ref update that the fs makes and make sure it is consistent
> and valid. I've run this through with xfstests and haven't gotten any false
> positives. Thanks,
>
> Signed-off-by: Josef Bacik <jba...@fb.com>
> ---
> v2->v3:
> - fix use after free in an error case
Can you please split the patch into more parts? This is just too big.
* the parameter changes, one per patch
* add ref-veriy.*
* new mount option and enabling the ref-verify
Apart from the specific comments written inline, here's list of thing
that I saw repeatd in several places:
printk instead of the btrfs_* error helpers - the bare printk will not
tell youw which filesystem is affected so it's not helpful when there
are several btrfs filesytems active
please don't split long strings
please don't use %Lu or %Ld format string, %llu
GFP_NOFS -- it's used on the open_ctree path so GFP_KERNEL is the right
and safe flag
misc small coding style issues
I'm half way through reviewing it from the functional side, so far it
looks good.
> fs/btrfs/Kconfig | 10 +
> fs/btrfs/Makefile | 1 +
> fs/btrfs/ctree.c | 2 +-
> fs/btrfs/ctree.h | 14 +-
> fs/btrfs/disk-io.c | 15 +
> fs/btrfs/extent-tree.c | 44 ++-
> fs/btrfs/file.c | 10 +-
> fs/btrfs/inode.c | 9 +-
> fs/btrfs/ioctl.c | 2 +-
> fs/btrfs/ref-verify.c | 1019
> ++++++++++++++++++++++++++++++++++++++++++++++++
> fs/btrfs/ref-verify.h | 51 +++
> fs/btrfs/relocation.c | 14 +-
> fs/btrfs/super.c | 17 +
> fs/btrfs/tree-log.c | 2 +-
> 14 files changed, 1178 insertions(+), 32 deletions(-)
> create mode 100644 fs/btrfs/ref-verify.c
> create mode 100644 fs/btrfs/ref-verify.h
>
> diff --git a/fs/btrfs/Kconfig b/fs/btrfs/Kconfig
> index 80e9c18..77d7f74 100644
> --- a/fs/btrfs/Kconfig
> +++ b/fs/btrfs/Kconfig
> @@ -89,3 +89,13 @@ config BTRFS_ASSERT
> any of the assertions trip. This is meant for btrfs developers only.
>
> If unsure, say N.
> +
> +config BTRFS_FS_REF_VERIFY
> + bool "Btrfs with the ref verify tool compiled in"
> + depends on BTRFS_FS
must be N by default
> + help
> + Enable run-time extent reference verification instrumentation. This
> + is meant to be used by btrfs developers for tracking down extent
> + reference problems or verifying they didn't break something.
> +
> + If unsure, say N.
> diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
> index 128ce17..3172751 100644
> --- a/fs/btrfs/Makefile
> +++ b/fs/btrfs/Makefile
> @@ -13,6 +13,7 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o
> root-tree.o dir-item.o \
>
> btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o
> btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o
> +btrfs-$(CONFIG_BTRFS_FS_REF_VERIFY) += ref-verify.o
>
> btrfs-$(CONFIG_BTRFS_FS_RUN_SANITY_TESTS) += tests/free-space-tests.o \
> tests/extent-buffer-tests.o tests/btrfs-tests.o \
> diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
> index 6d49db7..a4812ce 100644
> --- a/fs/btrfs/ctree.c
> +++ b/fs/btrfs/ctree.c
> @@ -192,7 +192,7 @@ struct extent_buffer *btrfs_lock_root_node(struct
> btrfs_root *root)
> * tree until you end up with a lock on the root. A locked buffer
> * is returned, with a reference held.
> */
> -static struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root
> *root)
> +struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root)
> {
> struct extent_buffer *eb;
>
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index d49b045..4fa3ddd 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -1098,6 +1098,12 @@ struct btrfs_fs_info {
> u32 nodesize;
> u32 sectorsize;
> u32 stripesize;
> +
> +#ifdef CONFIG_BTRFS_FS_REF_VERIFY
> + spinlock_t ref_verify_lock;
> + struct rb_root block_tree;
> + bool ref_verify_enabled;
the on/off bit can be added to the fs_info::flags instead
> +#endif
> };
>
> static inline struct btrfs_fs_info *btrfs_sb(struct super_block *sb)
> @@ -1336,6 +1342,7 @@ static inline u32 BTRFS_MAX_XATTR_SIZE(const struct
> btrfs_fs_info *info)
> #define BTRFS_MOUNT_FRAGMENT_METADATA (1 << 25)
> #define BTRFS_MOUNT_FREE_SPACE_TREE (1 << 26)
> #define BTRFS_MOUNT_NOLOGREPLAY (1 << 27)
> +#define BTRFS_MOUNT_REF_VERIFY (1 << 28)
>
> #define BTRFS_DEFAULT_COMMIT_INTERVAL (30)
> #define BTRFS_DEFAULT_MAX_INLINE (2048)
> @@ -2627,7 +2634,7 @@ void btrfs_free_tree_block(struct btrfs_trans_handle
> *trans,
> struct extent_buffer *buf,
> u64 parent, int last_ref);
> int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
> - u64 root_objectid, u64 owner,
> + struct btrfs_root *root, u64 owner,
> u64 offset, u64 ram_bytes,
> struct btrfs_key *ins);
> int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
> @@ -2646,7 +2653,7 @@ int btrfs_set_disk_extent_flags(struct
> btrfs_trans_handle *trans,
> u64 bytenr, u64 num_bytes, u64 flags,
> int level, int is_data);
> int btrfs_free_extent(struct btrfs_trans_handle *trans,
> - struct btrfs_fs_info *fs_info,
> + struct btrfs_root *root,
> u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
> u64 owner, u64 offset);
>
> @@ -2658,7 +2665,7 @@ void btrfs_prepare_extent_commit(struct btrfs_fs_info
> *fs_info);
> int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
> struct btrfs_fs_info *fs_info);
> int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
> - struct btrfs_fs_info *fs_info,
> + struct btrfs_root *root,
> u64 bytenr, u64 num_bytes, u64 parent,
> u64 root_objectid, u64 owner, u64 offset);
>
> @@ -2803,6 +2810,7 @@ void btrfs_set_item_key_safe(struct btrfs_fs_info
> *fs_info,
> const struct btrfs_key *new_key);
> struct extent_buffer *btrfs_root_node(struct btrfs_root *root);
> struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root);
> +struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root);
> int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
> struct btrfs_key *key, int lowest_level,
> u64 min_trans);
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 4a41158..32215e5 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -50,6 +50,7 @@
> #include "sysfs.h"
> #include "qgroup.h"
> #include "compression.h"
> +#include "ref-verify.h"
>
> #ifdef CONFIG_X86
> #include <asm/cpufeature.h>
> @@ -2664,6 +2665,12 @@ int open_ctree(struct super_block *sb,
> INIT_RADIX_TREE(&fs_info->reada_tree, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
> spin_lock_init(&fs_info->reada_lock);
>
> +#ifdef CONFIG_BTRFS_FS_REF_VERIFY
> + spin_lock_init(&fs_info->ref_verify_lock);
> + fs_info->block_tree = RB_ROOT;
> + fs_info->ref_verify_enabled = true;
> +#endif
Please move that to a helper and avoid the #ifdef here
> +
> fs_info->thread_pool_size = min_t(unsigned long,
> num_online_cpus() + 2, 8);
>
> @@ -3079,6 +3086,13 @@ int open_ctree(struct super_block *sb,
> if (ret)
> goto fail_trans_kthread;
>
> +#ifdef CONFIG_BTRFS_FS_REF_VERIFY
> + if (btrfs_build_ref_tree(fs_info)) {
> + fs_info->ref_verify_enabled = false;
btrfs_build_ref_tree will return 0 when REF_VERIFY is off, using the
fs_info::flags for the enabled part will make it possible to get rid of
the ifdeffery
> + printk(KERN_ERR "BTRFS: couldn't build ref tree\n");
> + }
> +#endif
> +
> /* do not make disk changes in broken FS or nologreplay is given */
> if (btrfs_super_log_root(disk_super) != 0 &&
> !btrfs_test_opt(fs_info, NOLOGREPLAY)) {
> @@ -3936,6 +3950,7 @@ void close_ctree(struct btrfs_fs_info *fs_info)
> cleanup_srcu_struct(&fs_info->subvol_srcu);
>
> btrfs_free_stripe_hash_table(fs_info);
> + btrfs_free_ref_cache(fs_info);
>
> __btrfs_free_block_rsv(root->orphan_block_rsv);
> root->orphan_block_rsv = NULL;
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 1464678..b68fb8c 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -39,6 +39,7 @@
> #include "math.h"
> #include "sysfs.h"
> #include "qgroup.h"
> +#include "ref-verify.h"
>
> #undef SCRAMBLE_DELAYED_REFS
>
> @@ -2110,16 +2111,20 @@ int btrfs_discard_extent(struct btrfs_fs_info
> *fs_info, u64 bytenr,
>
> /* Can return -ENOMEM */
> int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
> - struct btrfs_fs_info *fs_info,
> + struct btrfs_root *root,
> u64 bytenr, u64 num_bytes, u64 parent,
> u64 root_objectid, u64 owner, u64 offset)
> {
> + struct btrfs_fs_info *fs_info = root->fs_info;
> int old_ref_mod, new_ref_mod;
> int ret;
>
> BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
> root_objectid == BTRFS_TREE_LOG_OBJECTID);
>
> + btrfs_ref_tree_mod(root, bytenr, num_bytes, parent, root_objectid,
> + owner, offset, BTRFS_ADD_DELAYED_REF);
> +
> if (owner < BTRFS_FIRST_FREE_OBJECTID) {
> ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
> num_bytes, parent,
> @@ -3270,7 +3275,7 @@ static int __btrfs_mod_ref(struct btrfs_trans_handle
> *trans,
> int level;
> int ret = 0;
> int (*process_func)(struct btrfs_trans_handle *,
> - struct btrfs_fs_info *,
> + struct btrfs_root *,
> u64, u64, u64, u64, u64, u64);
>
>
> @@ -3310,7 +3315,7 @@ static int __btrfs_mod_ref(struct btrfs_trans_handle
> *trans,
>
> num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
> key.offset -= btrfs_file_extent_offset(buf, fi);
> - ret = process_func(trans, fs_info, bytenr, num_bytes,
> + ret = process_func(trans, root, bytenr, num_bytes,
> parent, ref_root, key.objectid,
> key.offset);
> if (ret)
> @@ -3318,7 +3323,7 @@ static int __btrfs_mod_ref(struct btrfs_trans_handle
> *trans,
> } else {
> bytenr = btrfs_node_blockptr(buf, i);
> num_bytes = fs_info->nodesize;
> - ret = process_func(trans, fs_info, bytenr, num_bytes,
> + ret = process_func(trans, root, bytenr, num_bytes,
> parent, ref_root, level - 1, 0);
> if (ret)
> goto fail;
> @@ -7154,6 +7159,10 @@ void btrfs_free_tree_block(struct btrfs_trans_handle
> *trans,
> if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
> int old_ref_mod, new_ref_mod;
>
> + btrfs_ref_tree_mod(root, buf->start, buf->len, parent,
> + root->root_key.objectid,
> + btrfs_header_level(buf), 0,
> + BTRFS_DROP_DELAYED_REF);
> ret = btrfs_add_delayed_tree_ref(fs_info, trans, buf->start,
> buf->len, parent,
> root->root_key.objectid,
> @@ -7206,16 +7215,21 @@ void btrfs_free_tree_block(struct btrfs_trans_handle
> *trans,
>
> /* Can return -ENOMEM */
> int btrfs_free_extent(struct btrfs_trans_handle *trans,
> - struct btrfs_fs_info *fs_info,
> + struct btrfs_root *root,
> u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
> u64 owner, u64 offset)
> {
> + struct btrfs_fs_info *fs_info = root->fs_info;
> int old_ref_mod, new_ref_mod;
> int ret;
>
> if (btrfs_is_testing(fs_info))
> return 0;
>
> + if (root_objectid != BTRFS_TREE_LOG_OBJECTID)
> + btrfs_ref_tree_mod(root, bytenr, num_bytes, parent,
> + root_objectid, owner, offset,
> + BTRFS_DROP_DELAYED_REF);
>
> /*
> * tree log blocks never actually go into the extent allocation
> @@ -8183,17 +8197,22 @@ static int alloc_reserved_tree_block(struct
> btrfs_trans_handle *trans,
> }
>
> int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
> - u64 root_objectid, u64 owner,
> + struct btrfs_root *root, u64 owner,
> u64 offset, u64 ram_bytes,
> struct btrfs_key *ins)
> {
> - struct btrfs_fs_info *fs_info = trans->fs_info;
> + struct btrfs_fs_info *fs_info = root->fs_info;
> int ret;
>
> - BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
> + BUG_ON(root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
> +
> + btrfs_ref_tree_mod(root, ins->objectid, ins->offset, 0,
> + root->root_key.objectid, owner, offset,
> + BTRFS_ADD_DELAYED_EXTENT);
>
> ret = btrfs_add_delayed_data_ref(fs_info, trans, ins->objectid,
> - ins->offset, 0, root_objectid, owner,
> + ins->offset, 0,
> + root->root_key.objectid, owner,
> offset, ram_bytes,
> BTRFS_ADD_DELAYED_EXTENT, NULL, NULL);
> return ret;
> @@ -8415,6 +8434,9 @@ struct extent_buffer *btrfs_alloc_tree_block(struct
> btrfs_trans_handle *trans,
> extent_op->is_data = false;
> extent_op->level = level;
>
> + btrfs_ref_tree_mod(root, ins.objectid, ins.offset, parent,
> + root_objectid, level, 0,
> + BTRFS_ADD_DELAYED_EXTENT);
> ret = btrfs_add_delayed_tree_ref(fs_info, trans, ins.objectid,
> ins.offset, parent,
> root_objectid, level,
> @@ -8771,7 +8793,7 @@ static noinline int do_walk_down(struct
> btrfs_trans_handle *trans,
> ret);
> }
> }
> - ret = btrfs_free_extent(trans, fs_info, bytenr, blocksize,
> + ret = btrfs_free_extent(trans, root, bytenr, blocksize,
> parent, root->root_key.objectid,
> level - 1, 0);
> if (ret)
> @@ -10264,6 +10286,8 @@ int btrfs_remove_block_group(struct
> btrfs_trans_handle *trans,
> * remove it.
> */
> free_excluded_extents(fs_info, block_group);
> + btrfs_free_ref_tree_range(fs_info, block_group->key.objectid,
> + block_group->key.offset);
>
> memcpy(&key, &block_group->key, sizeof(key));
> index = get_block_group_index(block_group);
> diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
> index aeab384..7d01dc4 100644
> --- a/fs/btrfs/file.c
> +++ b/fs/btrfs/file.c
> @@ -856,7 +856,7 @@ int __btrfs_drop_extents(struct btrfs_trans_handle *trans,
> btrfs_mark_buffer_dirty(leaf);
>
> if (update_refs && disk_bytenr > 0) {
> - ret = btrfs_inc_extent_ref(trans, fs_info,
> + ret = btrfs_inc_extent_ref(trans, root,
> disk_bytenr, num_bytes, 0,
> root->root_key.objectid,
> new_key.objectid,
> @@ -940,7 +940,7 @@ int __btrfs_drop_extents(struct btrfs_trans_handle *trans,
> extent_end = ALIGN(extent_end,
> fs_info->sectorsize);
> } else if (update_refs && disk_bytenr > 0) {
> - ret = btrfs_free_extent(trans, fs_info,
> + ret = btrfs_free_extent(trans, root,
> disk_bytenr, num_bytes, 0,
> root->root_key.objectid,
> key.objectid, key.offset -
> @@ -1234,7 +1234,7 @@ int btrfs_mark_extent_written(struct btrfs_trans_handle
> *trans,
> extent_end - split);
> btrfs_mark_buffer_dirty(leaf);
>
> - ret = btrfs_inc_extent_ref(trans, fs_info, bytenr, num_bytes,
> + ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes,
> 0, root->root_key.objectid,
> ino, orig_offset);
> if (ret) {
> @@ -1268,7 +1268,7 @@ int btrfs_mark_extent_written(struct btrfs_trans_handle
> *trans,
> extent_end = other_end;
> del_slot = path->slots[0] + 1;
> del_nr++;
> - ret = btrfs_free_extent(trans, fs_info, bytenr, num_bytes,
> + ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
> 0, root->root_key.objectid,
> ino, orig_offset);
> if (ret) {
> @@ -1288,7 +1288,7 @@ int btrfs_mark_extent_written(struct btrfs_trans_handle
> *trans,
> key.offset = other_start;
> del_slot = path->slots[0];
> del_nr++;
> - ret = btrfs_free_extent(trans, fs_info, bytenr, num_bytes,
> + ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
> 0, root->root_key.objectid,
> ino, orig_offset);
> if (ret) {
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 0038de5..f9f9de5 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -2215,8 +2215,9 @@ static int insert_reserved_file_extent(struct
> btrfs_trans_handle *trans,
> if (ret < 0)
> goto out;
> qg_released = ret;
> - ret = btrfs_alloc_reserved_file_extent(trans, root->root_key.objectid,
> - btrfs_ino(BTRFS_I(inode)), file_pos, qg_released, &ins);
> + ret = btrfs_alloc_reserved_file_extent(trans, root,
> + btrfs_ino(BTRFS_I(inode)),
> + file_pos, qg_released, &ins);
> out:
> btrfs_free_path(path);
>
> @@ -2668,7 +2669,7 @@ static noinline int relink_extent_backref(struct
> btrfs_path *path,
> inode_add_bytes(inode, len);
> btrfs_release_path(path);
>
> - ret = btrfs_inc_extent_ref(trans, fs_info, new->bytenr,
> + ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
> new->disk_len, 0,
> backref->root_id, backref->inum,
> new->file_pos); /* start - extent_offset */
> @@ -4659,7 +4660,7 @@ int btrfs_truncate_inode_items(struct
> btrfs_trans_handle *trans,
> root == fs_info->tree_root)) {
> btrfs_set_path_blocking(path);
> bytes_deleted += extent_num_bytes;
> - ret = btrfs_free_extent(trans, fs_info, extent_start,
> + ret = btrfs_free_extent(trans, root, extent_start,
> extent_num_bytes, 0,
> btrfs_header_owner(leaf),
> ino, extent_offset);
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 137402f..d4e3eb6 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -3704,7 +3704,7 @@ static int btrfs_clone(struct inode *src, struct inode
> *inode,
> if (disko) {
> inode_add_bytes(inode, datal);
> ret = btrfs_inc_extent_ref(trans,
> - fs_info,
> + root,
> disko, diskl, 0,
> root->root_key.objectid,
>
> btrfs_ino(BTRFS_I(inode)),
> diff --git a/fs/btrfs/ref-verify.c b/fs/btrfs/ref-verify.c
> new file mode 100644
> index 0000000..5d3aa8b
> --- /dev/null
> +++ b/fs/btrfs/ref-verify.c
> @@ -0,0 +1,1019 @@
> +/*
> + * 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;
> + 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;
> +}
> +
> +static void update_block_entry(struct btrfs_root *root, struct block_entry
> *be,
> + struct root_entry *re)
> +{
> + struct root_entry *exist;
> +
> + exist = insert_root_entry(&be->roots, re);
> + if (exist) {
> + kfree(re);
> + re = exist;
> + }
> + be->num_refs++;
> +}
> +
> +#ifdef CONFIG_STACK_TRACE
> +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 ref_action *ra)
> +{
> + struct stack_trace trace;
> + 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 ref_action *ra)
> +{
> + printk(KERN_ERR " No stacktrace support\n");
> +}
> +#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_root *root, u64
> bytenr,
> + u64 len, u64 root_objectid)
> +{
> + struct btrfs_fs_info *fs_info = root->fs_info;
> + struct block_entry *be = NULL, *exist;
> + struct root_entry *re = NULL;
> +
> + re = kmalloc(sizeof(struct root_entry), GFP_NOFS);
> + be = kmalloc(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) {
> + update_block_entry(root, exist, re);
> + kfree(be);
> + be = exist;
> + goto out;
> + }
> +
> + be->num_refs = 1;
> + be->metadata = 0;
> + be->roots = RB_ROOT;
> + be->refs = RB_ROOT;
> + INIT_LIST_HEAD(&be->actions);
> + if (insert_root_entry(&be->roots, re)) {
> + rb_erase(&be->node, &fs_info->block_tree);
> + kfree(re);
> + kfree(be);
> + be = ERR_PTR(-EINVAL);
> + ASSERT(0);
> + }
> +out:
> + spin_unlock(&fs_info->ref_verify_lock);
> + return be;
> +}
> +
> +static int add_tree_block(struct btrfs_root *root, u64 parent, u64 bytenr,
> + int level)
> +{
> + struct btrfs_fs_info *fs_info = root->fs_info;
> + struct block_entry *be;
> + struct root_entry *re;
> + struct ref_entry *ref = NULL, *exist;
> + struct ref_action *ra;
> +
> + ref = kmalloc(sizeof(struct ref_entry), GFP_NOFS);
> + if (!ref)
> + return -ENOMEM;
> +
> + ra = kmalloc(sizeof(struct ref_action), GFP_NOFS);
> + if (!ra) {
> + kfree(ref);
> + return -ENOMEM;
> + }
> +
> + if (parent)
> + ref->root_objectid = 0;
> + else
> + ref->root_objectid = root->objectid;
> + ref->parent = parent;
> + ref->owner = level;
> + ref->offset = 0;
> + ref->num_refs = 1;
> +
> + /*
> + * Action is tied to the delayed ref actions, so just use
> + * UPDATE_DELAYED_HEAD to indicate we got this during a scan.
> + */
> + ra->action = BTRFS_UPDATE_DELAYED_HEAD;
> + ra->root = root->objectid;
> + memcpy(&ra->ref, ref, sizeof(struct ref_entry));
> + __save_stack_trace(ra);
> + INIT_LIST_HEAD(&ra->list);
> +
> + be = add_block_entry(root, bytenr, fs_info->nodesize, root->objectid);
> + if (IS_ERR(be)) {
> + kfree(ref);
> + kfree(ra);
> + return PTR_ERR(be);
> + }
> +
> + spin_lock(&fs_info->ref_verify_lock);
> + be->metadata = 1;
> +
> + if (!parent) {
> + re = lookup_root_entry(&be->roots, root->objectid);
> + ASSERT(re);
> + re->num_refs++;
> + }
> + exist = insert_ref_entry(&be->refs, ref);
> + if (exist) {
> + exist->num_refs++;
> + kfree(ref);
> + }
> + list_add_tail(&ra->list, &be->actions);
> + spin_unlock(&fs_info->ref_verify_lock);
> +
> + return 0;
> +}
> +
> +static int process_leaf(struct btrfs_root *root, struct btrfs_path *path,
> + int shared)
> +{
> + struct extent_buffer *leaf = path->nodes[0];
> + struct btrfs_file_extent_item *fi;
> + struct block_entry *be;
> + struct ref_entry *ref = NULL, *exist;
> + struct root_entry *re;
> + struct ref_action *ra;
> + u64 bytenr, num_bytes, offset;
> + struct btrfs_key key;
> + int i = 0;
> + int nritems = btrfs_header_nritems(leaf);
> + u8 type;
> +
> + for (i = 0; i < nritems; i++) {
> + btrfs_item_key_to_cpu(leaf, &key, i);
> + if (key.type != BTRFS_EXTENT_DATA_KEY)
> + continue;
> + fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
> + type = btrfs_file_extent_type(leaf, fi);
> + if (type == BTRFS_FILE_EXTENT_INLINE)
> + continue;
> + ASSERT(type == BTRFS_FILE_EXTENT_REG ||
> + type == BTRFS_FILE_EXTENT_PREALLOC);
> + bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
> + if (bytenr == 0)
> + continue;
> + num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
> + offset = key.offset - btrfs_file_extent_offset(leaf, fi);
> +
> + be = add_block_entry(root, bytenr, num_bytes, root->objectid);
> + if (IS_ERR(be))
> + return PTR_ERR(be);
> + ref = kmalloc(sizeof(struct ref_entry), GFP_NOFS);
> + if (!ref)
> + return -ENOMEM;
> + ra = kmalloc(sizeof(struct ref_action), GFP_NOFS);
> + if (!ra) {
> + kfree(ref);
> + return -ENOMEM;
> + }
> +
> + if (shared) {
> + ref->root_objectid = 0;
> + ref->parent = leaf->start;
> + } else {
> + ref->root_objectid = root->objectid;
> + ref->parent = 0;
> + }
> + ref->owner = key.objectid;
> + ref->offset = key.offset -
> + btrfs_file_extent_offset(leaf, fi);
> + ref->num_refs = 1;
> +
> + ra->action = BTRFS_UPDATE_DELAYED_HEAD;
> + ra->root = root->objectid;
> + memcpy(&ra->ref, ref, sizeof(struct ref_entry));
> + __save_stack_trace(ra);
> + INIT_LIST_HEAD(&ra->list);
> +
> + spin_lock(&root->fs_info->ref_verify_lock);
> +
> + if (!shared) {
> + re = lookup_root_entry(&be->roots, root->objectid);
> + ASSERT(re);
> + re->num_refs++;
> + }
> +
> + exist = insert_ref_entry(&be->refs, ref);
> + if (exist) {
> + kfree(ref);
> + exist->num_refs++;
> + }
> + list_add_tail(&ra->list, &be->actions);
> + spin_unlock(&root->fs_info->ref_verify_lock);
> + }
> +
> + return 0;
> +}
> +
> +static int add_shared_refs(struct btrfs_root *root, struct btrfs_path *path,
> + int level)
> +{
> + int i;
> + int ret = 0;
> +
> + if (level == 0)
> + return process_leaf(root, path, 1);
> +
> + for (i = 0; i < btrfs_header_nritems(path->nodes[level]); i++) {
> + u64 bytenr;
> +
> + bytenr = btrfs_node_blockptr(path->nodes[level], i);
> + ret = add_tree_block(root, path->nodes[level]->start, bytenr,
> + level-1);
level - 1
> + 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)
> +{
> + struct btrfs_fs_info *fs_info = root->fs_info;
> + struct extent_buffer *eb;
> + u64 bytenr, gen;
> + int ret = 0;
> +
> + while (level >= 0) {
> + if (btrfs_header_owner(path->nodes[level]) != root->objectid) {
> + u64 refs, flags;
missing newline
> + if (!btrfs_block_can_be_shared(root,
> path->nodes[level]))
> + break;
> + eb = path->nodes[level];
> + ret = btrfs_lookup_extent_info(NULL, fs_info,
> + eb->start, level, 1,
> + &refs, &flags);
> + if (ret)
> + break;
> + if (refs == 0) {
> + WARN_ON(1);
> + ret = -EINVAL;
> + break;
> + }
> +
> + if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
> + ret = add_shared_refs(root, path, level);
> + break;
> + }
> + if (level) {
> + 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, bytenr, gen);
> + if (!eb || !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;
> +
> + ret = add_tree_block(root, 0, bytenr, level-1);
> + if (ret)
> + break;
> + } else if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
> + root == root->fs_info->tree_root) {
> + ret = process_leaf(root, path, 0);
> + 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 = 0;
> +
> + while (l < BTRFS_MAX_LEVEL) {
This is a for cycle in disguise
> + if (!path->nodes[l]) {
> + l++;
> + continue;
> + }
> + if (!l)
> + goto drop;
> + path->slots[l]++;
> + if (path->slots[l] < btrfs_header_nritems(path->nodes[l])) {
> + *level = l;
> + return 0;
> + }
> +drop:
> + 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;
> + l++;
> + }
> +
> + return 1;
> +}
> +
> +static int build_ref_tree_for_root(struct btrfs_root *root)
> +{
> + struct btrfs_path *path;
> + struct extent_buffer *eb;
> + int level;
> + int ret = 0;
> +
> + path = btrfs_alloc_path();
> + if (!path)
> + return -ENOMEM;
> +
> + eb = btrfs_read_lock_root_node(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;
> +
> + ret = add_tree_block(root, 0, eb->start, level);
> + if (ret) {
> + btrfs_free_path(path);
> + return ret;
> + }
> +
> + while (1) {
> + ret = walk_down_tree(root, path, level);
> + if (ret)
> + break;
> + ret = walk_up_tree(root, path, &level);
> + if (ret < 0)
> + break;
> + if (ret > 0) {
> + ret = 0;
> + break;
> + }
> + }
> + if (ret)
> + btrfs_free_ref_cache(root->fs_info);
> + btrfs_free_path(path);
> + return ret;
> +}
> +
> +
> +static void dump_ref_action(struct ref_action *ra)
> +{
> + printk(KERN_ERR " Ref action %d, root %llu, ref_root %llu, parent "
> + "%llu, owner %llu, offset %llu, num_refs %llu\n",
> + ra->action, ra->root, ra->ref.root_objectid, ra->ref.parent,
> + ra->ref.owner, ra->ref.offset, ra->ref.num_refs);
> + __print_stack_trace(ra);
> +}
> +
> +/*
> + * Dumps all the information from the block entry to printk, it's going to be
> + * awesome.
> + */
> +static void dump_block_entry(struct block_entry *be)
> +{
> + struct ref_entry *ref;
> + struct root_entry *re;
> + struct ref_action *ra;
> + struct rb_node *n;
> +
> + printk(KERN_ERR "Dumping block entry [%llu %llu], num_refs %llu, "
> + "metadata %d\n", be->bytenr, be->len, be->num_refs,
> + be->metadata);
> +
> + for (n = rb_first(&be->refs); n; n = rb_next(n)) {
> + ref = rb_entry(n, struct ref_entry, node);
> + printk(KERN_ERR " Ref root %llu, parent %llu, owner %llu, "
> + "offset %llu, num_refs %llu\n", 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);
> + printk(KERN_ERR " Root entry %llu, num_refs %llu\n",
> + re->root_objectid, re->num_refs);
> + }
> +
> + list_for_each_entry(ra, &be->actions, list)
> + dump_ref_action(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 ref_entry *ref = NULL, *exist;
> + struct ref_action *ra = NULL;
> + struct block_entry *be = NULL;
> + struct root_entry *re;
> + int ret = 0;
> + bool metadata = owner < BTRFS_FIRST_FREE_OBJECTID;
> + bool update_caller_root = root->objectid != ref_root;
> +
> + if (!btrfs_test_opt(root->fs_info, REF_VERIFY))
> + return 0;
> +
> + if (!root->fs_info->ref_verify_enabled)
> + return 0;
> +
> + ref = kmalloc(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->root_objectid = 0;
> + } else {
> + ref->root_objectid = ref_root;
> + }
> + ref->parent = parent;
> + 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_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) {
> + update_caller_root = false;
> +
> + /*
> + * 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, bytenr, num_bytes, ref_root);
> + if (IS_ERR(be)) {
> + kfree(ra);
> + ret = PTR_ERR(be);
> + goto out;
> + }
> +
> + spin_lock(&root->fs_info->ref_verify_lock);
> + if (metadata)
> + be->metadata = 1;
> +
> + if (be->num_refs != 1) {
> + printk(KERN_ERR "re-allocated a block that still has "
> + "references to it!\n");
> + dump_block_entry(be);
> + dump_ref_action(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;
> +
> + re = kmalloc(sizeof(struct root_entry), GFP_NOFS);
> + if (!re) {
> + kfree(ref);
> + kfree(ra);
> + ret = -ENOMEM;
> + goto out;
> + }
> +
> + /*
> + * The ref root is the original owner, we want to lookup the
> + * root responsible for this modification.
> + */
> + 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) {
> + printk(KERN_ERR "Trying to do action %d to bytenr %Lu "
> + " num_bytes %Lu but there is no existing "
> + "entry!\n", action, bytenr, num_bytes);
> + dump_ref_action(ra);
> + kfree(ref);
> + kfree(ra);
> + goto out_unlock;
> + }
> +
> + tmp = insert_root_entry(&be->roots, re);
> + if (tmp)
> + kfree(re);
> + }
> +
> + exist = insert_ref_entry(&be->refs, ref);
> + if (exist) {
> + if (action == BTRFS_DROP_DELAYED_REF) {
> + if (exist->num_refs == 0) {
> + printk(KERN_ERR "Dropping a ref for a "
> + "existing root that doesn't have a ref "
> + "on the block\n");
> + dump_block_entry(be);
> + dump_ref_action(ra);
> + kfree(ra);
> + goto out_unlock;
> + }
> + exist->num_refs--;
> + if (exist->num_refs == 0) {
> + rb_erase(&exist->node, &be->refs);
> + kfree(exist);
> + }
> + } else {
> + exist->num_refs++;
> + }
> + kfree(ref);
> + } else {
> + if (action == BTRFS_DROP_DELAYED_REF) {
> + printk(KERN_ERR "Dropping a ref for a root that "
> + "doesn't have a ref on the block\n");
> + dump_block_entry(be);
> + dump_ref_action(ra);
> + kfree(ra);
> + goto out_unlock;
> + }
> + }
> +
> + re = lookup_root_entry(&be->roots, ref_root);
> + if (!re) {
> + /*
> + * This really shouldn't happen but there where bugs when I
> + * originally put this stuff together so I would hit it every
> + * once and a while. Now everything is working so it really
> + * won't get tripped, but if anybody starts messing around in
> + * here it will be a nice sanity check instead of a panic. We
> + * can remove it later if we need to.
> + */
> + printk(KERN_ERR "Failed to find root %llu for %llu",
> + ref_root, be->bytenr);
> + dump_block_entry(be);
> + dump_ref_action(ra);
> + kfree(ra);
> + goto out_unlock;
> + }
> + ASSERT(re);
> + if (action == BTRFS_DROP_DELAYED_REF) {
> + if (!parent)
> + re->num_refs--;
> + be->num_refs--;
> + } else if (action == BTRFS_ADD_DELAYED_REF) {
> + be->num_refs++;
> + if (!parent)
> + 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)
> + root->fs_info->ref_verify_enabled = false;
> + 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) {
> + printk(KERN_ERR "Block entry overlaps a block "
> + "group [%llu,%llu]!\n", start, len);
> + dump_block_entry(be);
> + continue;
> + }
> + if (be->bytenr < start)
> + continue;
> + if (be->bytenr >= start + len)
> + break;
> + if (be->bytenr + be->len > start + len) {
> + printk(KERN_ERR "Block entry overlaps a block "
> + "group [%llu,%llu]!\n", start, len);
> + dump_block_entry(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 btrfs_key key;
> + u64 last_objectid = BTRFS_EXTENT_TREE_OBJECTID;
> + int ret;
> +
> + if (!btrfs_test_opt(fs_info, REF_VERIFY))
> + return 0;
> +
> + path = btrfs_alloc_path();
> + if (!path)
> + return -ENOMEM;
> +
> + ret = build_ref_tree_for_root(fs_info->tree_root);
> + if (ret)
> + goto out;
> +
> + ret = build_ref_tree_for_root(fs_info->chunk_root);
> + if (ret)
> + goto out;
> +again:
> + key.objectid = last_objectid;
> + key.type = BTRFS_ROOT_ITEM_KEY;
> + key.offset = 0;
> +
> + ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
> + if (ret < 0)
> + goto out;
> + while (1) {
> + if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
> + ret = btrfs_next_leaf(fs_info->tree_root, path);
> + if (ret > 0) {
> + ret = 0;
> + break;
> + } else if (ret) {
> + break;
> + }
> + }
> + btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
> + if (key.type != BTRFS_ROOT_ITEM_KEY) {
> + path->slots[0]++;
> + continue;
> + }
> + btrfs_release_path(path);
> + root = btrfs_get_fs_root(fs_info, &key, false);
> + if (IS_ERR(root)) {
> + ret = PTR_ERR(root);
> + break;
> + }
> + last_objectid = key.objectid + 1;
> + ret = build_ref_tree_for_root(root);
> + if (ret)
> + break;
> + goto again;
> + }
> +out:
> + btrfs_free_path(path);
> + return ret;
> +}
> diff --git a/fs/btrfs/ref-verify.h b/fs/btrfs/ref-verify.h
> new file mode 100644
> index 0000000..8f508c0
> --- /dev/null
> +++ b/fs/btrfs/ref-verify.h
> @@ -0,0 +1,51 @@
> +/*
> + * 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.
> + */
> +#ifndef __REF_VERIFY__
> +#define __REF_VERIFY__
> +
> +#ifdef CONFIG_BTRFS_FS_REF_VERIFY
> +int btrfs_build_ref_tree(struct btrfs_fs_info *fs_info);
> +void btrfs_free_ref_cache(struct btrfs_fs_info *fs_info);
> +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);
> +void btrfs_free_ref_tree_range(struct btrfs_fs_info *fs_info, u64 start,
> + u64 len);
> +#else
> +static inline int btrfs_build_ref_tree(struct btrfs_fs_info *fs_info)
> +{
> + return 0;
> +}
> +
> +static inline void btrfs_free_ref_cache(struct btrfs_fs_info *fs_info)
> +{
> +}
> +
> +static inline 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)
> +{
> + return 0;
> +}
> +
> +static inline void btrfs_free_ref_tree_range(struct btrfs_fs_info *fs_info,
> + u64 start, u64 len)
> +{
> +}
> +#endif /* CONFIG_BTRFS_FS_REF_VERIFY */
> +#endif /* _REF_VERIFY__ */
> diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
> index b67844b..8a15464 100644
> --- a/fs/btrfs/relocation.c
> +++ b/fs/btrfs/relocation.c
> @@ -1733,7 +1733,7 @@ int replace_file_extents(struct btrfs_trans_handle
> *trans,
> dirty = 1;
>
> key.offset -= btrfs_file_extent_offset(leaf, fi);
> - ret = btrfs_inc_extent_ref(trans, fs_info, new_bytenr,
> + ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
> num_bytes, parent,
> btrfs_header_owner(leaf),
> key.objectid, key.offset);
> @@ -1742,7 +1742,7 @@ int replace_file_extents(struct btrfs_trans_handle
> *trans,
> break;
> }
>
> - ret = btrfs_free_extent(trans, fs_info, bytenr, num_bytes,
> + ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
> parent, btrfs_header_owner(leaf),
> key.objectid, key.offset);
> if (ret) {
> @@ -1943,21 +1943,21 @@ int replace_path(struct btrfs_trans_handle *trans,
> path->slots[level], old_ptr_gen);
> btrfs_mark_buffer_dirty(path->nodes[level]);
>
> - ret = btrfs_inc_extent_ref(trans, fs_info, old_bytenr,
> + ret = btrfs_inc_extent_ref(trans, src, old_bytenr,
> blocksize, path->nodes[level]->start,
> src->root_key.objectid, level - 1, 0);
> BUG_ON(ret);
> - ret = btrfs_inc_extent_ref(trans, fs_info, new_bytenr,
> + ret = btrfs_inc_extent_ref(trans, dest, new_bytenr,
> blocksize, 0, dest->root_key.objectid,
> level - 1, 0);
> BUG_ON(ret);
>
> - ret = btrfs_free_extent(trans, fs_info, new_bytenr, blocksize,
> + ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
> path->nodes[level]->start,
> src->root_key.objectid, level - 1, 0);
> BUG_ON(ret);
>
> - ret = btrfs_free_extent(trans, fs_info, old_bytenr, blocksize,
> + ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
> 0, dest->root_key.objectid, level - 1,
> 0);
> BUG_ON(ret);
> @@ -2799,7 +2799,7 @@ static int do_relocation(struct btrfs_trans_handle
> *trans,
> trans->transid);
> btrfs_mark_buffer_dirty(upper->eb);
>
> - ret = btrfs_inc_extent_ref(trans, root->fs_info,
> + ret = btrfs_inc_extent_ref(trans, root,
> node->eb->start, blocksize,
> upper->eb->start,
> btrfs_header_owner(upper->eb),
> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
> index 0b7a1d8..aad45dc 100644
> --- a/fs/btrfs/super.c
> +++ b/fs/btrfs/super.c
> @@ -326,6 +326,9 @@ enum {
> #ifdef CONFIG_BTRFS_DEBUG
> Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
> #endif
> +#ifdef CONFIG_BTRFS_FS_REF_VERIFY
> + Opt_ref_verify,
> +#endif
> Opt_err,
> };
>
> @@ -387,6 +390,9 @@ static const match_table_t tokens = {
> {Opt_fragment_metadata, "fragment=metadata"},
> {Opt_fragment_all, "fragment=all"},
> #endif
> +#ifdef CONFIG_BTRFS_FS_REF_VERIFY
> + {Opt_ref_verify, "ref_verify"},
> +#endif
> {Opt_err, NULL},
> };
>
> @@ -817,6 +823,13 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char
> *options,
> btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
> break;
> #endif
> +#ifdef CONFIG_BTRFS_FS_REF_VERIFY
> + case Opt_ref_verify:
> + btrfs_info(info, "doing ref verification");
> + btrfs_set_opt(info->mount_opt,
> + REF_VERIFY);
> + break;
> +#endif
> case Opt_err:
> btrfs_info(info, "unrecognized mount option '%s'", p);
> ret = -EINVAL;
> @@ -1295,6 +1308,10 @@ static int btrfs_show_options(struct seq_file *seq,
> struct dentry *dentry)
> if (btrfs_test_opt(info, FRAGMENT_METADATA))
> seq_puts(seq, ",fragment=metadata");
> #endif
> +#ifdef CONFIG_BTRFS_FS_REF_VERIFY
> + if (btrfs_test_opt(info, REF_VERIFY))
> + seq_puts(seq, ",ref_verify");
> +#endif
> seq_printf(seq, ",subvolid=%llu",
> BTRFS_I(d_inode(dentry))->root->root_key.objectid);
> seq_puts(seq, ",subvol=");
> diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
> index da9d802..34b6070 100644
> --- a/fs/btrfs/tree-log.c
> +++ b/fs/btrfs/tree-log.c
> @@ -717,7 +717,7 @@ static noinline int replay_one_extent(struct
> btrfs_trans_handle *trans,
> ret = btrfs_lookup_data_extent(fs_info, ins.objectid,
> ins.offset);
> if (ret == 0) {
> - ret = btrfs_inc_extent_ref(trans, fs_info,
> + ret = btrfs_inc_extent_ref(trans, root,
> ins.objectid, ins.offset,
> 0, root->root_key.objectid,
> key->objectid, offset);
> --
> 2.7.4
>
> --
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