Hi Liubo,
I couldn't apply your V4 patch against the btrfs-next HEAD. Do you have
a github branch which I can checkout?
Thanks,
Itaru
On Wed, Oct 31, 2012 at 9:55 PM, Liu Bo <bo.li.liu@xxxxxxxxxx> wrote:
> On 10/31/2012 08:13 PM, Itaru Kitayama wrote:
>> Hi LiuBo:
>>
>> I am seeing another warning with your patch applied btrfs-next.
>>
>
> Hi Itaru,
>
> Thanks for testing, you seems to be using an old version, since in the new version
> record_extent_backrefs() does not own a WARN_ON().
>
> Could you please test it again with the new patches applied?
>
> thanks,
> liubo
>
>
>> [ 5224.531560] ------------[ cut here ]------------
>> [ 5224.531565] WARNING: at fs/btrfs/inode.c:2054
>> record_extent_backrefs+0x87/0xe0()
>> [ 5224.531567] Hardware name: Bochs
>> [ 5224.531568] Modules linked in: microcode ppdev psmouse nfsd nfs_acl
>> auth_rpcgss serio_raw nfs fscache lockd binfmt_misc sunrpc cirrus
>> parport_pc ttm drm_kms_helper drm sysimgblt i2c_piix4 sysfillrect
>> syscopyarea i2c_core lp parport floppy
>> [ 5224.531591] Pid: 2485, comm: btrfs-endio-wri Tainted: G W
>> 3.7.0-rc1-v11+ #53
>> [ 5224.531592] Call Trace:
>> [ 5224.531598] [<ffffffff81061c63>] warn_slowpath_common+0x93/0xc0
>> [ 5224.531600] [<ffffffff81061caa>] warn_slowpath_null+0x1a/0x20
>> [ 5224.531603] [<ffffffff81322287>] record_extent_backrefs+0x87/0xe0
>> [ 5224.531606] [<ffffffff8132d10b>] btrfs_finish_ordered_io+0x8bb/0xa80
>> [ 5224.531611] [<ffffffff810ce300>] ? trace_hardirqs_off_caller+0xb0/0x140
>> [ 5224.531614] [<ffffffff8132d2e5>] finish_ordered_fn+0x15/0x20
>> [ 5224.531617] [<ffffffff8134beb7>] worker_loop+0x157/0x580
>> [ 5224.531620] [<ffffffff8134bd60>] ? btrfs_queue_worker+0x2f0/0x2f0
>> [ 5224.531624] [<ffffffff81090aa8>] kthread+0xe8/0xf0
>> [ 5224.531627] [<ffffffff810ce3c2>] ? get_lock_stats+0x22/0x70
>> [ 5224.531630] [<ffffffff810909c0>] ? kthread_create_on_node+0x160/0x160
>> [ 5224.531634] [<ffffffff817c1c6c>] ret_from_fork+0x7c/0xb0
>> [ 5224.531636] [<ffffffff810909c0>] ? kthread_create_on_node+0x160/0x160
>> [ 5224.531638] ---[ end trace 0256d2b5a195208c ]---
>>
>> I've compared some of the old extents logical addresses with the corresponding
>> object ids and offsets from the extent tree; some are just 8k off from
>> the found extents
>> and some keys are totally off.
>>
>> Itaru
>>
>> On Sat, Oct 27, 2012 at 7:28 PM, Liu Bo <bo.li.liu@xxxxxxxxxx> wrote:
>>> This comes from one of btrfs's project ideas,
>>> As we defragment files, we break any sharing from other snapshots.
>>> The balancing code will preserve the sharing, and defrag needs to grow this
>>> as well.
>>>
>>> Now we're able to fill the blank with this patch, in which we make full use of
>>> backref walking stuff.
>>>
>>> Here is the basic idea,
>>> o set the writeback ranges started by defragment with flag EXTENT_DEFRAG
>>> o at endio, after we finish updating fs tree, we use backref walking to find
>>> all parents of the ranges and re-link them with the new COWed file layout by
>>> adding corresponding backrefs.
>>>
>>> Originally patch by Li Zefan <lizf@xxxxxxxxxxxxxx>
>>> Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
>>> ---
>>> v3->v4:
>>> - fix duplicated refs bugs detected by mounting with autodefrag, thanks
>>> for the bug report from Mitch and Chris.
>>>
>>> fs/btrfs/inode.c | 609 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>> 1 files changed, 609 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
>>> index 85a1e50..35e6993 100644
>>> --- a/fs/btrfs/inode.c
>>> +++ b/fs/btrfs/inode.c
>>> @@ -54,6 +54,7 @@
>>> #include "locking.h"
>>> #include "free-space-cache.h"
>>> #include "inode-map.h"
>>> +#include "backref.h"
>>>
>>> struct btrfs_iget_args {
>>> u64 ino;
>>> @@ -1839,6 +1840,600 @@ out:
>>> return ret;
>>> }
>>>
>>> +/* snapshot-aware defrag */
>>> +struct sa_defrag_extent_backref {
>>> + struct rb_node node;
>>> + struct old_sa_defrag_extent *old;
>>> + u64 root_id;
>>> + u64 inum;
>>> + u64 file_pos;
>>> + u64 extent_offset;
>>> + u64 num_bytes;
>>> + u64 generation;
>>> +};
>>> +
>>> +struct old_sa_defrag_extent {
>>> + struct list_head list;
>>> + struct new_sa_defrag_extent *new;
>>> +
>>> + u64 extent_offset;
>>> + u64 bytenr;
>>> + u64 offset;
>>> + u64 len;
>>> + int count;
>>> +};
>>> +
>>> +struct new_sa_defrag_extent {
>>> + struct rb_root root;
>>> + struct list_head head;
>>> + struct btrfs_path *path;
>>> + struct inode *inode;
>>> + u64 file_pos;
>>> + u64 len;
>>> + u64 bytenr;
>>> + u64 disk_len;
>>> + u8 compress_type;
>>> +};
>>> +
>>> +static int backref_comp(struct sa_defrag_extent_backref *b1,
>>> + struct sa_defrag_extent_backref *b2)
>>> +{
>>> + if (b1->root_id < b2->root_id)
>>> + return -1;
>>> + else if (b1->root_id > b2->root_id)
>>> + return 1;
>>> +
>>> + if (b1->inum < b2->inum)
>>> + return -1;
>>> + else if (b1->inum > b2->inum)
>>> + return 1;
>>> +
>>> + if (b1->file_pos < b2->file_pos)
>>> + return -1;
>>> + else if (b1->file_pos > b2->file_pos)
>>> + return 1;
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static void backref_insert(struct rb_root *root,
>>> + struct sa_defrag_extent_backref *backref)
>>> +{
>>> + struct rb_node **p = &root->rb_node;
>>> + struct rb_node *parent = NULL;
>>> + struct sa_defrag_extent_backref *entry;
>>> + int ret;
>>> +
>>> + while (*p) {
>>> + parent = *p;
>>> + entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
>>> +
>>> + ret = backref_comp(backref, entry);
>>> + if (ret < 0)
>>> + p = &(*p)->rb_left;
>>> + else
>>> + /*
>>> + * Since space can be shared, so there can be
>>> + * some backrefs(extent tree to fs/file tree)
>>> + * whoes fs/file extents map to the same address.
>>> + * If so, we just put it after what we've found.
>>> + */
>>> + p = &(*p)->rb_right;
>>> + }
>>> +
>>> + rb_link_node(&backref->node, parent, p);
>>> + rb_insert_color(&backref->node, root);
>>> +}
>>> +
>>> +/*
>>> + * Note the backref might has changed, and in this case we just return 0.
>>> + */
>>> +static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
>>> + void *ctx)
>>> +{
>>> + struct btrfs_file_extent_item *extent;
>>> + struct btrfs_fs_info *fs_info;
>>> + struct old_sa_defrag_extent *old = ctx;
>>> + struct new_sa_defrag_extent *new = old->new;
>>> + struct btrfs_path *path = new->path;
>>> + struct btrfs_key key;
>>> + struct btrfs_root *root;
>>> + struct sa_defrag_extent_backref *backref;
>>> + struct extent_buffer *leaf;
>>> + struct inode *inode = new->inode;
>>> + int slot;
>>> + int ret;
>>> + u64 extent_offset;
>>> + u64 num_bytes;
>>> +
>>> + if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
>>> + inum == btrfs_ino(inode))
>>> + return 0;
>>> +
>>> + key.objectid = root_id;
>>> + key.type = BTRFS_ROOT_ITEM_KEY;
>>> + key.offset = (u64)-1;
>>> +
>>> + fs_info = BTRFS_I(inode)->root->fs_info;
>>> + root = btrfs_read_fs_root_no_name(fs_info, &key);
>>> + if (IS_ERR(root)) {
>>> + if (PTR_ERR(root) == -ENOENT)
>>> + return 0;
>>> + WARN_ON(1);
>>> + pr_debug("inum=%llu, offset=%llu, root_id=%llu\n",
>>> + inum, offset, root_id);
>>> + return PTR_ERR(root);
>>> + }
>>> +
>>> + key.objectid = inum;
>>> + key.type = BTRFS_EXTENT_DATA_KEY;
>>> + if (offset > (u64)-1 << 32)
>>> + key.offset = 0;
>>> + else
>>> + key.offset = offset;
>>> +
>>> + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
>>> + if (ret < 0) {
>>> + WARN_ON(1);
>>> + return ret;
>>> + }
>>> +
>>> + while (1) {
>>> + cond_resched();
>>> +
>>> + leaf = path->nodes[0];
>>> + slot = path->slots[0];
>>> +
>>> + if (slot >= btrfs_header_nritems(leaf)) {
>>> + ret = btrfs_next_leaf(root, path);
>>> + if (ret < 0) {
>>> + goto out;
>>> + } else if (ret > 0) {
>>> + ret = 0;
>>> + goto out;
>>> + }
>>> + continue;
>>> + }
>>> +
>>> + path->slots[0]++;
>>> +
>>> + btrfs_item_key_to_cpu(leaf, &key, slot);
>>> +
>>> + if (key.objectid > inum)
>>> + goto out;
>>> +
>>> + if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
>>> + continue;
>>> +
>>> + extent = btrfs_item_ptr(leaf, slot,
>>> + struct btrfs_file_extent_item);
>>> +
>>> + if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
>>> + continue;
>>> +
>>> + extent_offset = btrfs_file_extent_offset(leaf, extent);
>>> + if (key.offset - extent_offset != offset)
>>> + continue;
>>> +
>>> + num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
>>> + if (extent_offset >= old->extent_offset + old->offset +
>>> + old->len || extent_offset + num_bytes <=
>>> + old->extent_offset + old->offset)
>>> + continue;
>>> +
>>> + break;
>>> + }
>>> +
>>> + backref = kmalloc(sizeof(*backref), GFP_NOFS);
>>> + if (!backref) {
>>> + ret = -ENOENT;
>>> + goto out;
>>> + }
>>> +
>>> + backref->root_id = root_id;
>>> + backref->inum = inum;
>>> + backref->file_pos = offset + extent_offset;
>>> + backref->num_bytes = num_bytes;
>>> + backref->extent_offset = extent_offset;
>>> + backref->generation = btrfs_file_extent_generation(leaf, extent);
>>> + backref->old = old;
>>> + backref_insert(&new->root, backref);
>>> + old->count++;
>>> +out:
>>> + btrfs_release_path(path);
>>> + WARN_ON(ret);
>>> + return ret;
>>> +}
>>> +
>>> +static noinline bool record_extent_backrefs(struct btrfs_path *path,
>>> + struct new_sa_defrag_extent *new)
>>> +{
>>> + struct btrfs_fs_info *fs_info = BTRFS_I(new->inode)->root->fs_info;
>>> + struct old_sa_defrag_extent *old, *tmp;
>>> + int ret;
>>> +
>>> + new->path = path;
>>> +
>>> + list_for_each_entry_safe(old, tmp, &new->head, list) {
>>> + ret = iterate_inodes_from_logical(old->bytenr, fs_info,
>>> + path, record_one_backref,
>>> + old);
>>> + BUG_ON(ret < 0 && ret != -ENOENT);
>>> +
>>> + /* no backref to be processed for this extent */
>>> + if (!old->count) {
>>> + list_del(&old->list);
>>> + kfree(old);
>>> + }
>>> + }
>>> +
>>> + if (list_empty(&new->head))
>>> + return false;
>>> +
>>> + return true;
>>> +}
>>> +
>>> +/*
>>> + * Note the backref might has changed, and in this case we just return 0.
>>> + */
>>> +static noinline int relink_extent_backref(struct btrfs_path *path,
>>> + struct sa_defrag_extent_backref *prev,
>>> + struct sa_defrag_extent_backref *backref)
>>> +{
>>> + struct btrfs_file_extent_item *extent;
>>> + struct btrfs_file_extent_item *item;
>>> + struct btrfs_ordered_extent *ordered;
>>> + struct btrfs_trans_handle *trans;
>>> + struct btrfs_fs_info *fs_info;
>>> + struct btrfs_root *root;
>>> + struct btrfs_key key;
>>> + struct extent_buffer *leaf;
>>> + struct old_sa_defrag_extent *old = backref->old;
>>> + struct new_sa_defrag_extent *new = old->new;
>>> + struct inode *src_inode = new->inode;
>>> + struct inode *inode;
>>> + struct extent_state *cached = NULL;
>>> + int ret = 0;
>>> + u64 start;
>>> + u64 len;
>>> + u64 lock_start;
>>> + u64 lock_end;
>>> + bool merge = false;
>>> +
>>> + if (prev && prev->root_id == backref->root_id &&
>>> + prev->inum == backref->inum &&
>>> + prev->file_pos + prev->num_bytes == backref->file_pos)
>>> + merge = true;
>>> +
>>> + key.objectid = backref->root_id;
>>> + key.type = BTRFS_ROOT_ITEM_KEY;
>>> + key.offset = (u64)-1;
>>> +
>>> + fs_info = BTRFS_I(src_inode)->root->fs_info;
>>> + root = btrfs_read_fs_root_no_name(fs_info, &key);
>>> + if (IS_ERR(root)) {
>>> + if (PTR_ERR(root) == -ENOENT)
>>> + return 0;
>>> + return PTR_ERR(root);
>>> + }
>>> +
>>> + key.objectid = backref->inum;
>>> + key.type = BTRFS_INODE_ITEM_KEY;
>>> + key.offset = 0;
>>> +
>>> + inode = btrfs_iget(fs_info->sb, &key, root, NULL);
>>> + if (IS_ERR_OR_NULL(inode) || is_bad_inode(inode)) {
>>> + if (inode && !IS_ERR(inode))
>>> + iput(inode);
>>> + return 0;
>>> + }
>>> +
>>> + lock_start = backref->file_pos;
>>> + lock_end = backref->file_pos + backref->num_bytes - 1;
>>> + lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
>>> + 0, &cached);
>>> +
>>> + ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
>>> + if (ordered) {
>>> + btrfs_put_ordered_extent(ordered);
>>> + goto out_unlock;
>>> + }
>>> +
>>> + trans = btrfs_join_transaction(root);
>>> + if (IS_ERR(trans)) {
>>> + ret = PTR_ERR(trans);
>>> + goto out_unlock;
>>> + }
>>> +
>>> + key.objectid = backref->inum;
>>> + key.type = BTRFS_EXTENT_DATA_KEY;
>>> + key.offset = backref->file_pos;
>>> +
>>> + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
>>> + if (ret < 0) {
>>> + goto out_free_path;
>>> + } else if (ret > 0) {
>>> + ret = 0;
>>> + goto out_free_path;
>>> + }
>>> +
>>> + extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
>>> + struct btrfs_file_extent_item);
>>> +
>>> + if (btrfs_file_extent_generation(path->nodes[0], extent) !=
>>> + backref->generation)
>>> + goto out_free_path;
>>> +
>>> + btrfs_release_path(path);
>>> +
>>> + start = backref->file_pos;
>>> + if (backref->extent_offset < old->extent_offset + old->offset)
>>> + start += old->extent_offset + old->offset -
>>> + backref->extent_offset;
>>> +
>>> + len = min(backref->extent_offset + backref->num_bytes,
>>> + old->extent_offset + old->offset + old->len);
>>> + len -= max(backref->extent_offset, old->extent_offset + old->offset);
>>> +
>>> + ret = btrfs_drop_extents(trans, root, inode, start,
>>> + start + len, 1);
>>> + if (ret)
>>> + goto out_free_path;
>>> +again:
>>> + key.objectid = btrfs_ino(inode);
>>> + key.type = BTRFS_EXTENT_DATA_KEY;
>>> + key.offset = start;
>>> +
>>> + if (merge) {
>>> + struct btrfs_file_extent_item *fi;
>>> + u64 extent_len;
>>> + struct btrfs_key found_key;
>>> +
>>> + ret = btrfs_search_slot(trans, root, &key, path, 1, 1);
>>> + if (ret < 0)
>>> + goto out_free_path;
>>> +
>>> + path->slots[0]--;
>>> + leaf = path->nodes[0];
>>> + btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
>>> +
>>> + fi = btrfs_item_ptr(leaf, path->slots[0],
>>> + struct btrfs_file_extent_item);
>>> + extent_len = btrfs_file_extent_num_bytes(leaf, fi);
>>> +
>>> + if (btrfs_file_extent_disk_bytenr(leaf, fi) == new->bytenr &&
>>> + btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_REG &&
>>> + !btrfs_file_extent_compression(leaf, fi) &&
>>> + !btrfs_file_extent_encryption(leaf, fi) &&
>>> + !btrfs_file_extent_other_encoding(leaf, fi) &&
>>> + extent_len + found_key.offset == start) {
>>> + btrfs_set_file_extent_num_bytes(leaf, fi,
>>> + extent_len + len);
>>> + btrfs_mark_buffer_dirty(leaf);
>>> + inode_add_bytes(inode, len);
>>> +
>>> + ret = 1;
>>> + goto out_free_path;
>>> + } else {
>>> + merge = false;
>>> + btrfs_release_path(path);
>>> + goto again;
>>> + }
>>> + }
>>> +
>>> + ret = btrfs_insert_empty_item(trans, root, path, &key,
>>> + sizeof(*extent));
>>> + if (ret) {
>>> + btrfs_abort_transaction(trans, root, ret);
>>> + goto out_free_path;
>>> + }
>>> +
>>> + leaf = path->nodes[0];
>>> + item = btrfs_item_ptr(leaf, path->slots[0],
>>> + struct btrfs_file_extent_item);
>>> + btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
>>> + btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
>>> + btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
>>> + btrfs_set_file_extent_num_bytes(leaf, item, len);
>>> + btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
>>> + btrfs_set_file_extent_generation(leaf, item, trans->transid);
>>> + btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
>>> + btrfs_set_file_extent_compression(leaf, item, new->compress_type);
>>> + btrfs_set_file_extent_encryption(leaf, item, 0);
>>> + btrfs_set_file_extent_other_encoding(leaf, item, 0);
>>> +
>>> + btrfs_mark_buffer_dirty(leaf);
>>> + inode_add_bytes(inode, len);
>>> +
>>> + ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
>>> + new->disk_len, 0,
>>> + backref->root_id, backref->inum,
>>> + new->file_pos, 0); /* start - extent_offset */
>>> + if (ret) {
>>> + btrfs_abort_transaction(trans, root, ret);
>>> + goto out_free_path;
>>> + }
>>> +
>>> + ret = 1;
>>> +out_free_path:
>>> + btrfs_release_path(path);
>>> + btrfs_end_transaction(trans, root);
>>> +out_unlock:
>>> + unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
>>> + &cached, GFP_NOFS);
>>> + iput(inode);
>>> + return ret;
>>> +}
>>> +
>>> +static void relink_file_extents(struct new_sa_defrag_extent *new)
>>> +{
>>> + struct btrfs_path *path;
>>> + struct old_sa_defrag_extent *old, *tmp;
>>> + struct sa_defrag_extent_backref *backref;
>>> + struct sa_defrag_extent_backref *prev = NULL;
>>> + struct inode *inode;
>>> + struct btrfs_root *root;
>>> + struct rb_node *node;
>>> + int ret;
>>> +
>>> + inode = new->inode;
>>> + root = BTRFS_I(inode)->root;
>>> +
>>> + path = btrfs_alloc_path();
>>> + if (!path)
>>> + return;
>>> +
>>> + if (!record_extent_backrefs(path, new)) {
>>> + btrfs_free_path(path);
>>> + goto out;
>>> + }
>>> + btrfs_release_path(path);
>>> +
>>> + while (1) {
>>> + node = rb_first(&new->root);
>>> + if (!node)
>>> + break;
>>> + rb_erase(node, &new->root);
>>> +
>>> + backref = rb_entry(node, struct sa_defrag_extent_backref, node);
>>> +
>>> + ret = relink_extent_backref(path, prev, backref);
>>> + WARN_ON(ret < 0);
>>> +
>>> + kfree(prev);
>>> +
>>> + if (ret == 1)
>>> + prev = backref;
>>> + else
>>> + prev = NULL;
>>> + cond_resched();
>>> + }
>>> + kfree(prev);
>>> +
>>> + btrfs_free_path(path);
>>> +
>>> + list_for_each_entry_safe(old, tmp, &new->head, list) {
>>> + list_del(&old->list);
>>> + kfree(old);
>>> + }
>>> +out:
>>> + atomic_dec(&root->fs_info->defrag_running);
>>> + wake_up(&root->fs_info->transaction_wait);
>>> +
>>> + kfree(new);
>>> +}
>>> +
>>> +static struct new_sa_defrag_extent *
>>> +record_old_file_extents(struct inode *inode,
>>> + struct btrfs_ordered_extent *ordered)
>>> +{
>>> + struct btrfs_root *root = BTRFS_I(inode)->root;
>>> + struct btrfs_path *path;
>>> + struct btrfs_key key;
>>> + struct old_sa_defrag_extent *old, *tmp;
>>> + struct new_sa_defrag_extent *new;
>>> + int ret;
>>> +
>>> + new = kmalloc(sizeof(*new), GFP_NOFS);
>>> + if (!new)
>>> + return NULL;
>>> +
>>> + new->inode = inode;
>>> + new->file_pos = ordered->file_offset;
>>> + new->len = ordered->len;
>>> + new->bytenr = ordered->start;
>>> + new->disk_len = ordered->disk_len;
>>> + new->compress_type = ordered->compress_type;
>>> + new->root = RB_ROOT;
>>> + INIT_LIST_HEAD(&new->head);
>>> +
>>> + path = btrfs_alloc_path();
>>> + if (!path)
>>> + goto out_kfree;
>>> +
>>> + key.objectid = btrfs_ino(inode);
>>> + key.type = BTRFS_EXTENT_DATA_KEY;
>>> + key.offset = new->file_pos;
>>> +
>>> + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
>>> + if (ret < 0)
>>> + goto out_free_path;
>>> + if (ret > 0 && path->slots[0] > 0)
>>> + path->slots[0]--;
>>> +
>>> + /* find out all the old extents for the file range */
>>> + while (1) {
>>> + struct btrfs_file_extent_item *extent;
>>> + struct extent_buffer *l;
>>> + int slot;
>>> + u64 num_bytes;
>>> + u64 offset;
>>> + u64 end;
>>> +
>>> + l = path->nodes[0];
>>> + slot = path->slots[0];
>>> +
>>> + if (slot >= btrfs_header_nritems(l)) {
>>> + ret = btrfs_next_leaf(root, path);
>>> + if (ret < 0)
>>> + goto out_free_list;
>>> + else if (ret > 0)
>>> + break;
>>> + continue;
>>> + }
>>> +
>>> + btrfs_item_key_to_cpu(l, &key, slot);
>>> +
>>> + if (key.objectid != btrfs_ino(inode))
>>> + break;
>>> + if (key.type != BTRFS_EXTENT_DATA_KEY)
>>> + break;
>>> + if (key.offset >= new->file_pos + new->len)
>>> + break;
>>> +
>>> + extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
>>> +
>>> + num_bytes = btrfs_file_extent_num_bytes(l, extent);
>>> + if (key.offset + num_bytes < new->file_pos)
>>> + goto next;
>>> +
>>> + old = kmalloc(sizeof(*old), GFP_NOFS);
>>> + if (!old)
>>> + goto out_free_list;
>>> +
>>> + offset = max(new->file_pos, key.offset);
>>> + end = min(new->file_pos + new->len, key.offset + num_bytes);
>>> +
>>> + old->bytenr = btrfs_file_extent_disk_bytenr(l, extent);
>>> + BUG_ON(!old->bytenr);
>>> + old->extent_offset = btrfs_file_extent_offset(l, extent);
>>> + old->offset = offset - key.offset;
>>> + old->len = end - offset;
>>> + old->new = new;
>>> + old->count = 0;
>>> + list_add_tail(&old->list, &new->head);
>>> +next:
>>> + path->slots[0]++;
>>> + cond_resched();
>>> + }
>>> +
>>> + btrfs_free_path(path);
>>> + atomic_inc(&root->fs_info->defrag_running);
>>> +
>>> + return new;
>>> +
>>> +out_free_list:
>>> + list_for_each_entry_safe(old, tmp, &new->head, list) {
>>> + list_del(&old->list);
>>> + kfree(old);
>>> + }
>>> +out_free_path:
>>> + btrfs_free_path(path);
>>> +out_kfree:
>>> + kfree(new);
>>> + return NULL;
>>> +}
>>> +
>>> /*
>>> * helper function for btrfs_finish_ordered_io, this
>>> * just reads in some of the csum leaves to prime them into ram
>>> @@ -1856,6 +2451,7 @@ static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
>>> struct btrfs_trans_handle *trans = NULL;
>>> struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
>>> struct extent_state *cached_state = NULL;
>>> + struct new_sa_defrag_extent *new = NULL;
>>> int compress_type = 0;
>>> int ret;
>>> bool nolock;
>>> @@ -1892,6 +2488,15 @@ static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
>>> ordered_extent->file_offset + ordered_extent->len - 1,
>>> 0, &cached_state);
>>>
>>> + ret = test_range_bit(io_tree, ordered_extent->file_offset,
>>> + ordered_extent->file_offset + ordered_extent->len - 1,
>>> + EXTENT_DEFRAG, 1, cached_state);
>>> + if (ret && btrfs_root_last_snapshot(&root->root_item) >=
>>> + BTRFS_I(inode)->generation) {
>>> + /* the inode is shared */
>>> + new = record_old_file_extents(inode, ordered_extent);
>>> + }
>>> +
>>> if (nolock)
>>> trans = btrfs_join_transaction_nolock(root);
>>> else
>>> @@ -1965,6 +2570,10 @@ out:
>>> */
>>> btrfs_remove_ordered_extent(inode, ordered_extent);
>>>
>>> + /* for snapshot-aware defrag */
>>> + if (new)
>>> + relink_file_extents(new);
>>> +
>>> /* once for us */
>>> btrfs_put_ordered_extent(ordered_extent);
>>> /* once for the tree */
>>> --
>>> 1.7.7.6
>>>
>>> --
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