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btrfs: fix truncate throttling
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We have a bunch of magic to make sure we're throttling delayed refs when
truncating a file.  Now that we have a delayed refs rsv and a mechanism
for refilling that reserve simply use that instead of all of this magic.

Reviewed-by: Nikolay Borisov <[email protected]>
Signed-off-by: Josef Bacik <[email protected]>
Signed-off-by: David Sterba <[email protected]>
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josefbacik authored and kdave committed Dec 17, 2018
1 parent db2462a commit 28bad21
Showing 1 changed file with 17 additions and 62 deletions.
79 changes: 17 additions & 62 deletions fs/btrfs/inode.c
Original file line number Diff line number Diff line change
Expand Up @@ -4442,31 +4442,6 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
return err;
}

static int truncate_space_check(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 bytes_deleted)
{
struct btrfs_fs_info *fs_info = root->fs_info;
int ret;

/*
* This is only used to apply pressure to the enospc system, we don't
* intend to use this reservation at all.
*/
bytes_deleted = btrfs_csum_bytes_to_leaves(fs_info, bytes_deleted);
bytes_deleted *= fs_info->nodesize;
ret = btrfs_block_rsv_add(root, &fs_info->trans_block_rsv,
bytes_deleted, BTRFS_RESERVE_NO_FLUSH);
if (!ret) {
trace_btrfs_space_reservation(fs_info, "transaction",
trans->transid,
bytes_deleted, 1);
trans->bytes_reserved += bytes_deleted;
}
return ret;

}

/*
* Return this if we need to call truncate_block for the last bit of the
* truncate.
Expand Down Expand Up @@ -4511,7 +4486,6 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
u64 bytes_deleted = 0;
bool be_nice = false;
bool should_throttle = false;
bool should_end = false;

BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);

Expand Down Expand Up @@ -4724,15 +4698,7 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
btrfs_abort_transaction(trans, ret);
break;
}
if (btrfs_should_throttle_delayed_refs(trans))
btrfs_async_run_delayed_refs(fs_info,
trans->delayed_ref_updates * 2,
trans->transid, 0);
if (be_nice) {
if (truncate_space_check(trans, root,
extent_num_bytes)) {
should_end = true;
}
if (btrfs_should_throttle_delayed_refs(trans))
should_throttle = true;
}
Expand All @@ -4743,7 +4709,7 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,

if (path->slots[0] == 0 ||
path->slots[0] != pending_del_slot ||
should_throttle || should_end) {
should_throttle) {
if (pending_del_nr) {
ret = btrfs_del_items(trans, root, path,
pending_del_slot,
Expand All @@ -4755,23 +4721,24 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
pending_del_nr = 0;
}
btrfs_release_path(path);
if (should_throttle) {
unsigned long updates = trans->delayed_ref_updates;
if (updates) {
trans->delayed_ref_updates = 0;
ret = btrfs_run_delayed_refs(trans,
updates * 2);
if (ret)
break;
}
}

/*
* if we failed to refill our space rsv, bail out
* and let the transaction restart
* We can generate a lot of delayed refs, so we need to
* throttle every once and a while and make sure we're
* adding enough space to keep up with the work we are
* generating. Since we hold a transaction here we
* can't flush, and we don't want to FLUSH_LIMIT because
* we could have generated too many delayed refs to
* actually allocate, so just bail if we're short and
* let the normal reservation dance happen higher up.
*/
if (should_end) {
ret = -EAGAIN;
break;
if (should_throttle) {
ret = btrfs_delayed_refs_rsv_refill(fs_info,
BTRFS_RESERVE_NO_FLUSH);
if (ret) {
ret = -EAGAIN;
break;
}
}
goto search_again;
} else {
Expand All @@ -4797,18 +4764,6 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
}

btrfs_free_path(path);

if (be_nice && bytes_deleted > SZ_32M && (ret >= 0 || ret == -EAGAIN)) {
unsigned long updates = trans->delayed_ref_updates;
int err;

if (updates) {
trans->delayed_ref_updates = 0;
err = btrfs_run_delayed_refs(trans, updates * 2);
if (err)
ret = err;
}
}
return ret;
}

Expand Down

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