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@@ -272,6 +272,7 @@ enum btrfs_trans_type {
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TRANS_JOIN,
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TRANS_USERSPACE,
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TRANS_JOIN_NOLOCK,
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+ TRANS_JOIN_FREEZE,
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};
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static int may_wait_transaction(struct btrfs_root *root, int type)
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@@ -341,7 +342,11 @@ again:
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if (!h)
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return ERR_PTR(-ENOMEM);
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- sb_start_intwrite(root->fs_info->sb);
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+ if (!__sb_start_write(root->fs_info->sb, SB_FREEZE_FS, false)) {
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+ if (type == TRANS_JOIN_FREEZE)
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+ return ERR_PTR(-EPERM);
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+ sb_start_intwrite(root->fs_info->sb);
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+ }
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if (may_wait_transaction(root, type))
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wait_current_trans(root);
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@@ -424,6 +429,11 @@ struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root
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return start_transaction(root, 0, TRANS_USERSPACE, 0);
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}
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+struct btrfs_trans_handle *btrfs_join_transaction_freeze(struct btrfs_root *root)
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+{
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+ return start_transaction(root, 0, TRANS_JOIN_FREEZE, 0);
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+}
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+
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/* wait for a transaction commit to be fully complete */
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static noinline void wait_for_commit(struct btrfs_root *root,
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struct btrfs_transaction *commit)
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