btrfs: relocation: review the call sites which can be interrupted by signal
commit 44d354abf3
upstream.
Since most metadata reservation calls can return -EINTR when get
interrupted by fatal signal, we need to review the all the metadata
reservation call sites.
In relocation code, the metadata reservation happens in the following
sites:
- btrfs_block_rsv_refill() in merge_reloc_root()
merge_reloc_root() is a pretty critical section, we don't want to be
interrupted by signal, so change the flush status to
BTRFS_RESERVE_FLUSH_LIMIT, so it won't get interrupted by signal.
Since such change can be ENPSPC-prone, also shrink the amount of
metadata to reserve least amount avoid deadly ENOSPC there.
- btrfs_block_rsv_refill() in reserve_metadata_space()
It calls with BTRFS_RESERVE_FLUSH_LIMIT, which won't get interrupted
by signal.
- btrfs_block_rsv_refill() in prepare_to_relocate()
- btrfs_block_rsv_add() in prepare_to_relocate()
- btrfs_block_rsv_refill() in relocate_block_group()
- btrfs_delalloc_reserve_metadata() in relocate_file_extent_cluster()
- btrfs_start_transaction() in relocate_block_group()
- btrfs_start_transaction() in create_reloc_inode()
Can be interrupted by fatal signal and we can handle it easily.
For these call sites, just catch the -EINTR value in btrfs_balance()
and count them as canceled.
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
ae3f93cafd
commit
38ab14b1e2
|
@ -2312,12 +2312,20 @@ static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
|
|||
btrfs_unlock_up_safe(path, 0);
|
||||
}
|
||||
|
||||
min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
|
||||
/*
|
||||
* In merge_reloc_root(), we modify the upper level pointer to swap the
|
||||
* tree blocks between reloc tree and subvolume tree. Thus for tree
|
||||
* block COW, we COW at most from level 1 to root level for each tree.
|
||||
*
|
||||
* Thus the needed metadata size is at most root_level * nodesize,
|
||||
* and * 2 since we have two trees to COW.
|
||||
*/
|
||||
min_reserved = fs_info->nodesize * btrfs_root_level(root_item) * 2;
|
||||
memset(&next_key, 0, sizeof(next_key));
|
||||
|
||||
while (1) {
|
||||
ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
|
||||
BTRFS_RESERVE_FLUSH_ALL);
|
||||
BTRFS_RESERVE_FLUSH_LIMIT);
|
||||
if (ret) {
|
||||
err = ret;
|
||||
goto out;
|
||||
|
|
|
@ -4261,7 +4261,22 @@ int btrfs_balance(struct btrfs_fs_info *fs_info,
|
|||
mutex_lock(&fs_info->balance_mutex);
|
||||
if (ret == -ECANCELED && atomic_read(&fs_info->balance_pause_req))
|
||||
btrfs_info(fs_info, "balance: paused");
|
||||
else if (ret == -ECANCELED && atomic_read(&fs_info->balance_cancel_req))
|
||||
/*
|
||||
* Balance can be canceled by:
|
||||
*
|
||||
* - Regular cancel request
|
||||
* Then ret == -ECANCELED and balance_cancel_req > 0
|
||||
*
|
||||
* - Fatal signal to "btrfs" process
|
||||
* Either the signal caught by wait_reserve_ticket() and callers
|
||||
* got -EINTR, or caught by btrfs_should_cancel_balance() and
|
||||
* got -ECANCELED.
|
||||
* Either way, in this case balance_cancel_req = 0, and
|
||||
* ret == -EINTR or ret == -ECANCELED.
|
||||
*
|
||||
* So here we only check the return value to catch canceled balance.
|
||||
*/
|
||||
else if (ret == -ECANCELED || ret == -EINTR)
|
||||
btrfs_info(fs_info, "balance: canceled");
|
||||
else
|
||||
btrfs_info(fs_info, "balance: ended with status: %d", ret);
|
||||
|
|
Loading…
Reference in New Issue