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btrfs: move ulist allocation out of transaction in quota enable

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The allocation happens with GFP_KERNEL after a transaction has been
started, this can potentially cause deadlock if reclaim tries to get the
memory by flushing filesystem data.

The fs_info::qgroup_ulist is not used during transaction start when
quotas are not enabled. The status bit BTRFS_FS_QUOTA_ENABLED is set
later in btrfs_quota_enable so it's safe to move it before the
transaction start.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2018-12-19 19:47:37 +01:00
parent aea6f028d0
commit 7503b83d80
1 changed files with 6 additions and 7 deletions
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13
fs/btrfs/qgroup.c
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@ -894,6 +894,12 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info)
if (fs_info->quota_root)
goto out;
fs_info->qgroup_ulist = ulist_alloc(GFP_KERNEL);
if (!fs_info->qgroup_ulist) {
ret = -ENOMEM;
goto out;
}
/*
* 1 for quota root item
* 1 for BTRFS_QGROUP_STATUS item
@ -909,13 +915,6 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info)
goto out;
}
fs_info->qgroup_ulist = ulist_alloc(GFP_KERNEL);
if (!fs_info->qgroup_ulist) {
ret = -ENOMEM;
btrfs_abort_transaction(trans, ret);
goto out;
}
/*
* initially create the quota tree
*/